CHEMISTRY: 
General. Medical, and Pharmaceutical, 
INCLUDING 
THE CHEMISTRY OF THE U. S. PHARMACOPEIA. 
A MANUAL 
ON THE GENERAL PRINCIPLES OF THE SCIENCE, AND THEIR 
APPLICATIONS IN MEDICINE AND PHARMACY. 
BY 
JOHN ATTFIELD, F.R.S., 
M.A. A5D PH.D. OF THE UNIVERSITY OF TUBINGEN; F.I.C. J F.C.S. ; PROFESSOR OF PRACTICAL 
CHEMISTRY TO THE PHARMACEUTICAL SOCIETY OF GREAT BRITAIN ; FORMERLY DEMONSTRATOR 
OF CHEMISTRY AT ST. BARTHOLOMEWS HOSPITAL, LONDON ; HONORARY MEMBER OF PHAR- 
MACEUTICAL SOCIETIES OF GREAT BRITAIN, PARIS, ST. PETERSBURG, AUSTRIA, EAST 
FLANDERS, AND VICTORIA (AUSTRALIA) ; HONORARY MEMBER OF THE AMERICAN 
PHARMACEUTICAL ASSOCIATION ; HONORARY MEMBER OF THE COLLEGES OF 
PHARMACY OF PHILADELPHIA, NEW YORK, MASSACHUSETTS, CHICAGO, 
A>’n ONTARIO, AND OF THE PHARMACEUTICAL ASSOCIATIONS OF 
NEW HAMPSHIRE AND VIRGINIA; PRESIDENT OF THE 
BRITISH PHARMACEUTICAL CONFERENCE. 
TENTH EDITION, 
SPECIALLY REVISED BY THE AUTHOR FOR AMERICA. 
PHILADELPHIA: 
HENRY C. LEA’S SON & CO. 
1883. “But the greatest error of all is, mistaking the ultimate end of knowledge; for 
some men covet knowledge out of a natural curiosity and inquisitive temper; some 
to entertain the mind with variety and delight; some for ornament and reputation ; 
some for victory and contention ; many for lucre and a livelihood ; and but few for 
employing the divine gift of reason to the use and benefit of mankind. Thus some 
appear to seek in knowledge a couch for a searching spirit ; others, a walk for a 
wandering mind; others, a tower of state; others, a fort or commanding ground; 
and others, a shop for profit or sale; instead of a storehouse for the glory of the 
Creator and the endowment of human life.”—Lord Bacon. 
Entered according to Act of Cougress, in the year 1883, by 
HENRY C. LEA’S SON & CO., 
in the Office of the Librarian of Congress. All rights reserved. 
ELECTROTYPED BY 
WESTCOTT & THOMSON, PHIL A DA. 
COLLINS, PRINTER. PREFACE. 
Tiie short title on the hack of a book, and even the words 
on the title-page, are generally, and even necessarily, imperfect 
descriptions of the contents, and hence not unfrequently induce 
at the outset misconceptions in the minds of readers. The 
author of Chemistry: General, Medical, and Pharmaceutical, 
would at once state, therefore, that his chief aim is to teach 
the general truths of Chemistry to medical and pharmaceutical 
pupils. So far as laws and principles are concerned, the book 
is a work on General Chemistry; but, inasmuch as those laws 
and principles are elucidated and illustrated by that large por- 
tion of Chemistry which is directly interesting to medical prac- 
titioners and pharmacists, the book may be said to be a work on 
Medical Chemistry and Pharmaceutical Chemistry. Only in 
this conventional sense would the author speak of Medical and 
Pharmaceutical Chemistry, for the truths of Chemistry are 
the same for all students—crystalline verities which cannot be 
expanded or compressed to suit any class of workers. The 
leading principles of the science, however, can as easily he 
illustrated by or deduced from those facts which have interest 
as from those which have little or no special interest to the 
followers of medicine and pharmacy. The grand and simple 
leading truths of Chemistry, the lesser truths or principles, and 
nearly all the interesting relationships of elements and com- 
pounds—in a word, the science of Chemistry—can be taught to 
medical and pharmaceutical students with little other aid than 
that afforded by the materials which lie in rich abundance all 
around these workers. Such a mode of teaching “ the general 
principles of the science, and their applications in medicine and 
pharmacy,” is adopted in this volume. It is a mode which IV 
PREFACE. 
greatly increases tlie usefulness of the science to the class 
chiefly addressed, while it in no way diminishes the value of 
Chemistry as an instrument of mental culture—an instrument 
which sharpens and expands the powers of observation, which 
enlarges and strengthens memory and imagination, which gives 
point to the perceptive faculties, and which develops and elab- 
orates the powers of thought and of reason. 
This manual is intended, then, as a systematic exponent of 
the general truths of Chemistry, but is written mainly for the 
pupils, assistants, and principals engaged in medicine and 
pharmacy. It will be found equally useful as a reading-book 
for gentlemen having no opportunities of attending lectures or 
performing experiments, or, on the other hand, as a text-book 
for college pupils; while its comprehensive Index, containing 
eight thousand references, will fit the work for after-consulta- 
tion in the course of business or professional practice. 
From other chemical text-books it differs in three particu- 
lars : first, in the exclusion of matter relating to compounds 
which at present are only of interest to the scientific chemist; 
secondly, in containing more or less of the chemistry of every 
substance recognized officially or in general practice as a re- 
medial agent; thirdly, in the paragraphs being so cast that 
the volume may be used as a guide in studying the science 
experimentally. 
The order of subjects is that which, in the author’s opinion, 
best meets the requirements of medical and pharmaceutical 
students in Great Britain, Ireland, America, and the English 
colonies. Introductory pages are devoted to a few leading 
properties of the elements. A review of the facts thus unfolded 
affords opportunity for stating the views of philosophers respect- 
ing the manner in which these elements influence each other as 
components of terrestrial matter. The consideration in detail 
of the relations of the elementary and compound radicals fol- 
lows, synthetical and analytical bearings being pointed out, and 
attention frequently directed to connecting or underlying truths 
or general principles. The chemistry of substances naturally 
associated in vegetables and animals is next considered. Prac- PREFACE. 
V 
tical toxicology, and the chemical as well as microscopical cha- 
racters of morbid urine, urinary sediments, and calculi, are then 
given. The concluding sections form a laboratory-guide to 
the chemical and physical study of quantitative analysis. In 
the Appendix is a long table of tests for impurities in medi- 
cinal preparations; also a short one of the saturating powers 
of acids and alkalies, designed for use in prescribing and dis- 
pensing. 
In the course of the treatment outlined in the preceding 
paragraph it will be observed that the whole of the elements 
are first noticed very shortly, to give the pupil a general view 
of his course of study, and afterward at length and thoroughly; 
that the chemistry of the common metallic radicals precedes 
that of the rarer, and that the sections on the acidulous radicals 
are similarly divided ; while the hasylous radicals are arranged 
according to analytical relations, the common acidulous accord- 
ing to exchangeable value or quantivalence, and rarer acidulous 
radicals alphabetically. By this plan the more important facts 
and principles are repeatedly brought under consideration, the 
points of view, however, differing according as interest is con- 
centrated on physical, synthetical, analytical, or quantitative 
properties. This arrangement of matter was adopted, also, 
partly from the belief that the separate and general truths of 
Chemistry never enter the mind in the order of any scientific 
classification at present possible. In the current state of chem- 
ical knowledge consistency in the methodical arrangement even 
of elements can only be carried out in one direction, and is 
necessarily accompanied by inconsistencies in other directions— 
a result most perplexing to learners, and hence totally subver- 
sive of the chief advantage of classification. For this reason 
the writer has preferred to lead up to, rather than follow, scien- 
tific classification—has allowed analogies and affinities to sug- 
gest, rather than be suggested by, classification. Among the 
acidulous radicals, especially, any known system of classifica- 
tion would have given undue prominence to one set of relations 
and undeserved obscurity to others. Then, by separating more 
important from less important matter, instruction is adapted to VI 
PREFACE. 
the wants of gentlemen whose opportunities of studying Chem- 
istry vary greatly, and are unavoidably insufficient to enable 
them to gain a knowledge of the detail of the science, One 
great advantage of the mode of treatment is that difficulties of 
nomenclature, notation, chemical constitution, and even those 
arising from conventionality of language, are explained as they 
arise, instead of being massed under the head of “ Introductory 
Chapters,” “ Preliminary Considerations,” or “ General Re- 
marks,” which are not unfrequently too difficult to be under- 
stood by a beginner, too voluminous to be remembered except 
by the aid of subsequent lessons, and are consequently the 
cause of much trouble and confusion. This plan has also 
admitted of greater prominence being given to “ The General 
Principles of Chemical Philosophy,” the only section to which 
the student is asked frequently to return until he finds himself 
naturally employing those principles in the interpretation of 
the phenomena obtained by experiment. 
An elementary knowledge of the subjects of Gravitation, 
Heat, Light, Sound, Electricity, and Magnetism cannot be too 
strongly recommended to the student of Chemistry. The first 
portion of this manual would have been devoted to an exposi- 
tion of these branches of physics, so far as they bear on Chem- 
istry, did not the many special books on physics render such 
a course unnecessary. Quantitative chemical analysis fre- 
quently involving determinations of temperature, specific 
gravity, and atmospheric pressure, a few paragraphs on these 
subjects are made introductory to the sections on quantita- 
tive operations. 
The theories that matter consists of molecules and that mole- 
cules consist of atoms are freely adopted in this book, the 
author believing that in the present state of knowledge and 
education philosophic conceptions regarding Chemistry can 
only be taught to medical, pharmaceutical, and the great 
majority of general students by some objective aid. 
The chemical notation of the work is in accordance with 
modern theories. Equations illustrative of pharmacopoeial 
processes have a name attached to each formula. PREFACE. 
Chemical nomenclature has been modernized to the extent 
of defining the alkali-metal salts and the earthy compounds 
as those of potassium, sodium, ammonium, barium, calcium, 
magnesium, and aluminium, instead of potash, soda, ammonia, 
baryta, lime, magnesia, and alumina. The author confidently 
believes that this change, founded on views now adopted by 
all prominent writers on Chemistry, and used in the Pharmaco- 
poeia of the L nited States, will be accepted and become popular 
in medicine and pharmacy. It is a step in the direction of sim- 
plicity and consistency, and involves far less hypothesis than is 
contained in the old system. The name “ nitrate of potash,” for 
example, was based on the pure assumption that nitre contained 
oxide of potassium or potash and nitric anhydride, then errone- 
ously termed nitric acid. By the modern name, “ nitrate of 
potassium, all that is intended to be conveyed is that nitre 
contains the element common to all potassium compounds and 
the group of elements common to all nitrates. Under the old 
method students always experienced difficulty in distinguishing 
salts of the metal from salts of its oxide—salts of potassium, for 
instance, from salts of potash; under the new view no such 
difficulty arises. Sanies such as potassium nitrate or potassic 
nitrate are also consistent with modern views, but for general 
adoption are too unlike the original. The contractions in Latin 
for names like “nitrate of potassium” are identical with the 
contractions for names resembling “ nitrate of potash;” an 
accidental circumstance that will much facilitate the general 
introduction of the former among medical practitioners and 
pharmacists, and a practical advantage that must determine 
the choice over the other chemically equivalent names just 
mentioned. The author ventures to express some gratification 
that his use and advocacy of this system since the first edition 
of this manual was published in 1867 has resulted in its adop- 
tion, in 1873, in the “Pharmacopoeia of the United States,” 
and in the recommendation, from all medical, chemical, and 
pharmaceutical authorities in Ureat Britain, of its adoption in 
the next “ British Pharmacopoeia.” Pharmacy in these two 
countries will thus sooner or later, in the important matter of VIII 
PREFACE. 
chemical nomenclature, be in accord with the current state of 
chemical science. 
The Metric System of Weights and Measures (that which, 
doubtless, is destined to supersede all others) is alone used 
in the sections on Quantitative Analysis. In other parts of 
the manual avoirdupois weights and imperial measures are 
employed. 
It is hoped that the numerous etymological references scat- 
tered throughout the following pages will be found useful. 
Words in Greek have been rendered in English characters, 
letter for letter. The word “ official ” is used throughout for 
things recognized officially by the compilers of Pharmacopoeias ; 
“ officinal” in its original application to the ofiicina or shop. 
Students are strongly recommended to test their progress by 
frequent examination. To this end appropriate questions are 
appended to each subject. 
The author’s ideal of a manual of Chemistry for medical 
and pharmaceutical students is one in which not only the 
science of Chemistry is taught, but in which the chemistry of 
every substance having interest for the followers of medicine 
and pharmacy is noticed at more or less length in proportion to 
its importance, and at least its position in relation to the leading 
principles of Chemistry set forth with all attainable exactness. 
The extent to which he has realized this ideal he leaves to 
others to decide. Such a work will doubtless in certain parts 
partake of the character of a dictionary; but this is by no 
means a fault, especially if a good index be appended; for the 
points of contact between pure and applied chemistry are thus 
multiplied, and abundant outlets supplied by which a lover of 
the science may pass into other chemical domains by aid of 
other guides, or even into the regions of original research. 
Among the rarer alkaloids, bitter bodies, glucosides, salts of 
organic radicals, solid fats, fixed oils, volatile oils, resins, oleo- 
resins, gum-resins, balsams, and coloring-matters, mentioned 
in this volume, will be found many such points whence the 
ardent student may start for the obscure or untrodden paths 
of scientific chemistry. Within sixteen years a demand has arisen for ten large 
editions of this manual. The First, in 1867, was intended as 
a handbook of practical chemistry only; but the notes and re- 
marks made respecting most of the experiments were found 
to be so useful by students that this portion of the volume was 
in the Second Edition (1869) sufficiently extended to render the 
book more fairly complete in itself. In response to a call from 
professional friends in the United States in 1870, the work was 
revised by the author for the followers of medicine and phar- 
macy in America, the chemistry of the Preparations and 
Materia Medica of the United States Pharmacopoeia being 
introduced, and such other adaptations included as to form a 
Third Edition. A Fourth was presented to English workers 
in the autumn of 1872, and, founded on the Fourth, a Fifth 
Edition for American students in 1873. A very large Sixth 
Edition was published in England in 1875, a Seventh in 
America in 1876, an Eighth in 1879, and a Ninth in England 
in 1881. 
PREFACE. 
IX 
The present (Tenth) edition contains such alterations and 
additions as seemed necessary for the demonstration of the 
latest developments of chemical principles and the latest appli- 
cations of Chemistry in pharmacy. The work now includes the 
whole of the chemistry of the recently published United States 
Pharmacopoeia, and nearly all the chemistry of the British and 
Indian Pharmacopoeias. 
The Index contains eight thousand references. 
17 Bloomsbury Square, London, 
May 1, 1883. ADVICE TO STUDENTS. 
It is unnecessary to advise you to avoid studying merely by way 
of “ preparation for examination.” You will not so mistake the 
means for the end. You are studying to fit yourself for your posi- 
tion in the world. AVork diligently, study thoughtfully and delib- 
erately—above all, be thorough ; otherwise your knowledge will be 
transient, and will be unaccompanied by that enlightenment of the 
understanding, that mental training, mental discipline, and general 
elevation of the intellect, which constitute, in a word, education. 
AY hen you are thus educated, you will with ease and pleasure pass 
any examination in the knowledge you have thus acquired. 
All authorities on education, whether statesmen, teachers, or ex- 
aminers, regard “ Examination,” even by the most highly skilled 
“ Board,” with ample time at its disposal and a wide area from 
which to select questions, as but a partial test of knowledge and an 
extremely imperfect test of education. It is the best, however, that 
has been devised, and is especially useful when, following instead 
of leading education, it is restricted to the subjects of a well-de- 
fined, earnestly-followed, compulsory curriculum of study—a cur- 
riculum defined and directed by a competent representative body, 
wisely administered by properly qualified teachers, and earnestly 
followed by pupils possessing sound preliminary training. 
Students! in all honor and in the highest self-interest take care 
that any inefficiencies inseparable from “ examination ” are abun- 
dantly compensated by the extent and precision of your know- 
ledge and by the soundness and thoroughness of your whole 
education. 
List of Apparatus suitable for a three months’ course of practical 
chemistry in the summer session of medical schools or for any simi- 
lar series of lessons—including the preparation of elementary gases, 
analytical reactions of common metals and acidulous radicals, anal- 
ysis of single salts, chemical toxicology, and the examination of 
urine, urinary sediments, and calculi:— 
Apparatus for Experiments in Anaeysis. 
One dozen test-tubes. 
Test-tube stand. 
Test-tube cleaning-brush. 
A few pieces of glass tubing, 8 to 
16 in. long, with a few inches of 
India-rubber tubing to fit. 
Small flask. 
Two small beakers. 
Two small funnels. 
Two watch-glasses. 
Two or three glass rods. 
AVash-bottle. 
Small pestle and mortar. 
A 2-pint earthenware basin. 
A 2-inch and a 3-inch evap. basin. 
Two porcelain crucibles. 
Blowpipe. 
Crucible tongs. 
Round file. 
Triangular file. 
Small retort-stand. 
Sand-tray. 
AVire triangles. 
Platinum wire and foil. APPA RATUS. 
Test-paper. 
Filtei’-paper. 
Towel. 
Two dozen corks. 
(This set, packed in a deal box, can be obtained of any chemical- 
apparatus maker for about seven dollars.) 
Apparatus for Experiments in Synthesis and Analysis. 
A larger set, suitable for the performance of most of the synthet- 
ical as well as analytical experiments described in this manual:— 
A set of evaporating-basins, of 
the following sizes :— 
One One 4-inch. 
One 7J-inch. Two 3-inch. 
One Gj-inch. 
One retort-stand and three rings. 
Two test-glasses. 
One half-pint flask. 
One half quire of filter-paper. 
Two porcelain crucibles. 
One measure-glass, 5 oz. 
Blowpipe, 8-inch, Black’s. 
Two glass funnels. 
One doz. test-tubes (German glass). 
One test-tube brush. 
One pair of 8-inch brass crucible- 
tongs. 
Two soup-plates. 
One flat plate. 
Two spatula-knives. 
One pair of scissors. 
One round file. 
One triangular file. 
One half pound of glass rod. 
One half pound of glass tubing. 
One ft. small India-rubber tubing. 
Three dozen corks of various sizes. 
Platinum wire and foil. 
Test-papers. 
A nest of three beakers. 
(This set, packed in a case, can be obtained of any chemical-ap- 
paratus maker for about twelve dollars.) 
A sponge, towels, and note-book may be included. 
Furniture op a Laboratory. 
The following apparatus should be ready to the hands of students 
following an extended course of practical chemistry in a room set 
apart for the purpose:— 
A bench or table and stool. 
Water-supply and waste-pipe. 
A cupboard attached to a chimney 
with an outward draught. 
A furnace fed with coke; tongs, 
hot-plate, or sand-bath, etc. 
A waste-box. 
Shelves for chemicals and other 
materials in jars or bottles. 
Gas-supply and lamp with flexible 
tube (or a spirit-lamp and spirit). 
Test-tube rack, two dozen holes. 
Iron stand or cylinder for support- 
ing large dishes. 
Iron adapters for fitting dishes to 
cylinder. 
Pestle and mortar, 5 or 6 inches. 
One 6-inch funnel. 
Brown pan, 1- or 2-gallon. 
White jug, 1-gallon. 
Water-bottle, quart. 
Twenty-eight test-bottles, 6-oz. 
Other articles, such as flasks, retorts, receivers, condensers, large 
evaporating-dishes, may be obtained as wanted. In Quantitative 
Analysis the apparatus described in the sections on that subject will 
be required. REAGENTS—CHEMICALS. 
Reagents. 
Certain chemicals are used so frequently in analytical processes 
that it is desirable to have small quantities placed in bottles in front 
of the operator. As these “ reagents ” or “ test-solutions ” are gen- 
erally employed in a state of solution, nearly all the solid salts may 
at once be dissolved (in distilled water). The bottles employed 
should be well stoppered, and of five or six ounces capacity. The 
bottles should not be more than three-quarters full; single drops, 
if required, can then be poured out with ease and precision. The 
following list of test-solutions is recommended; directions for 
methods of preparing those not readily purchasable will be found 
by referring to the Index :— 
Sulphuric Acid, strong. 
Nitric Acid, strong. 
Hydrochloric Acid, strong 
Acetic Acid, strong. 
Sol. of Potash, 5 per cent, or B. P. 
“ Soda, 5 to 15 per cent. 
“ Ammon., 10 per ct. or B. P. 
Lime-water, saturated. 
The next nine may contain about 10 per cent, of solid salt 
Carbonate of Ammonium, with a 
little solution of Ammonia 
added. 
Chloride of Ammonium. 
Phosphate or Arseniate of Am- 
monium. 
Sulphydrate of Ammonium. 
Chloride of Barium. 
Chloride of Calcium. 
Phosphate of Sodium. 
Neutral Chromate. 
The succeeding seven may have a strength of about 5 per cent.:— 
Ferrocyanide of Potassium. 
Ferridcyanide of Potassium. 
Iodide of Potassium. 
Oxalate of Ammonium. 
Perehloride of Iron. 
Nitrate of Silver. 
Perehloride of Platinum. 
List of Chemicals. 
List of chemicals necessary for the practical study of the non- 
metallic elements mentioned on pp. 13 to 31. The quantities are 
sufficient for several experiments. 
Chlorate of Potassium . . 1 oz. 
Black Oxide of Manganese 1 oz. 
Zinc 1 oz. 
Oil of Vitriol 2 oz. 
Phosphorus f oz. 
Hydrochloric Acid - . . .1 oz. 
Sulphur 2 oz. 
Iodine } oz. 
List of chemicals necessary for the analytical study of the metal- 
lic and acidulous radicals (pp. 60 to 376). The quantities will de- 
pend on the frequency with which experiments are repeated or anal- 
yses performed; those mentioned are sufficient for one or two 
students. The articles are given in the order in which they 
will be required. The eight substances mentioned in the above 
list are included :— CHEMICALS. 
The set of test-solutions described 
on the previous page. 
Carbonate of Potassium . 1 oz. 
Tartaric Acid 1 oz. 
Litmus J oz. 
Sulphate of Magnesium . I oz. 
Sulphate of Zinc . . . . 1 oz. 
Alum 1 oz. 
Sulphide of Iron . . . . 1 lb. 
Oak-galls 1 oz. 
Sulphocyanate of Potassium £ oz. 
White Arsenic £ oz. 
Zinc \ lb. 
Charcoal £ lb. 
Sulphate of Iron . . . . 1 oz. 
Copper foil 1 oz. 
Sulphate of Copper ... 1 oz. 
Tartar Emetic | oz. 
M ercury 1 oz. 
Corrosive Sublimate . . . | oz. 
Calomel } oz. 
Tin 1 oz. 
Bicarbonate of Sodium . . 1 oz. 
Acetate of Lead . . . . 1 oz. 
Cyanide of Potassium . . J oz. 
Hyposulphite of Sodium . 1 oz. 
A Lithium Salt . . . 10 grs. 
Nitrate of Strontium . . J oz. 
Black Oxide of Manganese \ lb. 
Chloride of Manganese . | oz. 
Chloride of Cobalt . . 50 grs. 
Nitrate of Nickel . . \ oz. 
Chloride of Chromium . . \ oz. 
Gold leaves 2 or 3 
Chloride of Cadmium . . | oz. 
Nitrate of Bismuth . . . J oz. 
Bromide of Potassium . . \ oz. 
Starch 1 oz. 
Nitrate of Potassium . . 1 oz. 
Copper borings or turnings 1 oz. 
Indigo \ oz. 
Chlorate of Potassium . . 1 oz. 
Iodine | oz. 
Spirit of Wine . . . . 1 oz. 
Sulphur 1 oz. 
Acid Oxalate of Potassium 1 oz. 
Citric Acid 1 oz. 
Phosphorus 1 oz. 
Borax 1 oz. 
Turmeric 1 oz. 
Benzoic Acid .... 50 grs. 
Fluor Spar 1 oz. 
Tannic Acid .... 50 grs. 
Gallic Acid 50 grs. 
Pyrogallic Acid ... 50 grs. 
The quantities of materials required for the study of Chemistry 
synthetically will necessarily vary with the desires and tastes of 
the operator, or according to the number and requirements of stu- 
dents working together. CONTENTS. 
Preface iii 
Advice to Students xi 
Apparatus xi 
Reagents xiii 
Lists of Chemicals xiii 
Introduction.. 13 
General Properties of the Non-Metallic Elements 15 
Symbols and Derivation of Names of Elements 31 
The General Principles of Chemical Philosophy 36 
Common Metallic Elements, tiieir Official Preparations 
and Tests :— 
Salts of Potassium, Sodium, Ammonium, Barium, Calcium, 
Magnesium, Zinc, Aluminium, Iron, Arsenicum, Anti- 
mony, Copper, Mercury, Lead, Silver 59 
Analytical Charts for Ordinary Metals 218 
Rarer Metallic Elements, tiieir Official Preparations 
and Tests :— 
Salts of Lithium, Strontium, Manganese, Cobalt, Nickel, 
Chromium, Tin, Gold, Platinum, Cadmium, Bismuth.... 222 
Analytical Charts for all Metals 254 
Common Acidulous Radicals, Official Acids, and Tests :— 
Chlorides, Bromides, Iodides, Cyanides, Nitrates, Chlo- 
rates, Acetates, Sulphides, Sulphites, Sulphates, Car- 
bonates, Oxalates, Tartrates, Citrates, Phosphates, 
Borates 
Salts of Rarer Acidulous Radicals:— 
Benzoates, Cyanates, Formates, Hipppurates, Ferrocy- 
anides, Ferridcyanides, Fluorides, TIypopiiospiiites, IIy- 
PAGE XVI 
CONTENTS. 
posulphites, Lactates, M ALATES, Meconates, Metapiios- 
phates, Nitrites, Phosphites, Pyrophosphates, Sili- 
cates, SULPIIOCYANATES, TaNNATES, GaLLATES, URATES, 
Valerianates 332 
Analytical Chart for Acidulous Radicals 364 
Systematic Analysis 367 
Alkaloids, Amylaceous and Saccharine Substances, Glu- 
cosides, Alcohol and Allied Bodies, Albumenoid and 
Gelatigenous Substances, Pepsine, Fatty Bodies, Res- 
inoid Substances, Coloring-matters 376 
Toxicology 492 
Examination of Morbid Urine and Calculi 503 
Official Galenical Preparations 517 
Official Chemical Preparations 519 
Quantitative Analysis :— 
Introductory Remarks 519 
Determination of Atmospheric Pressure 521 
Determination of Temperature 522 
Estimation of Weight 528 
Weights and Measures 528 
Specific Gravity -. 541 
Correction of the Volume of Gases for Pressure 
and Temperature 547 
Volumetric Analysis 554 
Gravimetric Analysis 581 
Dialysis 633 
Appendix :— 
Table of Official Tests for Impurities in Prepara- 
tions of the United States Pharmacopceia 637 
Saturation Tables 658 
Table of the Proportion by Weight of Absolute Alco- 
hol in Spirits of different Specific Gravities 659 
The Elements, tiieir Symbols and Atomic Weights.... 660 
PAGE 
Index 663 CHEMISTRY: 
GENERAL, MEDICAL, AND PHARMACEUTICAL. 
INTRODUCTION* 
The infinite variety of solid, liquid, and gaseous substances 
of which our earth and atmosphere are composed, may be re- 
solved with more or less difficulty into distinct forms of matter 
appropriately termed Elements, for by no known means can 
they be further decomposed. Sixty-seven elements have been 
proved to exist. A few (such as gold) occur naturally in the 
uncombined state, but the greater number are combined in so 
subtle a manner as to conceal them from ordinary methods of 
observation. Thus none of the common properties of water 
indicate that it is composed of two elements, both gases, but 
differing much from each other: nor can the senses of sight, 
touch, and taste, or other common means of examination, de- 
tect in their concealment the three elements of which sugar is 
composed. The art by which these and all other compound 
substances are resolved into their elements is termed Chemis- 
try, a name derived possibly from the Arabic word kamai, to 
conceal.)- The art of chemistry also includes the construction 
of compounds from elements, and the conversion of substances 
of one character into those of another. The general principles 
* Students using this book as a guide iir following chemistry prac- 
tically should read the first three pages, and then commence work by 
preparing oxygen. All students should read the prefatory pages. 
f The idea that common metals contained valuable metals con- 
cealed within them was the one seed from which mainly sprung 
chemical knowledge. The men who endeavored to find the secret 
of such concealment were appropriately termed alchemists, and their 
efforts spoken of as alchemy (al kimia, from kamai, to conceal). Their 
persistent labors, generation after generation, were unsuccessful so 
far as the transmutation of baser metals into gold was concerned, yet 
were invaluable to posterity. For new substances were discovered 
and truths of nature unveiled; from these discoveries multiplication 
of discoveries resulted, and thus grew the still-growing branch of 
knowledge called Chemistry. 14 
THE ELEMENTS. 
or leading truths relating to the elements, to the manner in 
which they severally combine, and to the properties of the 
compound substances formed by their union, constitute the 
science of chemistry.* 
From these few words concerning the nature of the art and 
science of chemistry, it will be seen that in most of the occu- 
pations that engage the attention of man chemistry plays an 
important part—in few more so than in the practice of Thera- 
peuticsf and Pharmacy.J 
* Persons who practise the art and science of Chemistry are known 
as Chemists. Some two hundred or more years ago, and before chem- 
istry was a science, the “chemists” were the makers or vendors of 
chemicals, then only used as medicines. They were the successors of 
the Alchemists. In Great Britain these chemists and the herbalists, 
otherwise drug-grocers, otherwise druggists, gradually associated to 
form the “Chemists and Druggists.” Between the “Chemist and 
Druggist” and the Physician there existed the Apothecary—the 
putter together of medicines or compounder of physicians’ prescrip- 
tions. The Apothecary has since become a medical practitioner, pre- 
scriptions now being “made up” by the Chemist and Druggist. The 
latter in Great Britain, since the year 1868, has the title of Chemist 
and Druggist, his higher title being Pharmaceutical Chemist; these 
respective designations he legally assumes on passing the Minor and 
Major Examinations, conducted by the Pharmaceutical Society of 
Great Britain in accordance with the provisions of the Pharmacy Acts 
of 1852 and 1868. The whole class is often spoken of as that of 
Pharmacists or Pharmaceutists, terms also used in the United States. 
Other classes of chemists are the Analytical Chemists, who give spe- 
cial attention to Analysis: Manufacturing Chemists, who restrict their 
labors to the preparation of chemicals; while others devote a portion 
of their knowledge and energies to Chemical Education or to Chemical 
Research, or are appealed to as Consulting Chemists by the persons, 
firms, corporations, or governments needing chemical advice respect- 
ing industrial processes, hygienic matters, etc. The callings of the 
Consulting and Analytical Chemist are generally united, and the pro- 
fessional gentlemen who follow these conjoint avocations also not un- 
frequently occupy professorial or other tutorial positions, sometimes 
adding to these labors more or less work at original chemical research. 
In England, Scotland, and Ireland, nearly all the leading professional 
chemists are Fellows of the Institute of Chemistry of Great Britain and 
Ireland. 
f Therapeutics (depanevriKo^, therapeutikos, from dtpanevu, therapeuo, 
to nurse, serve, or cure) is that branch of medicine which treats of 
the application of remedies for diseases; it includes dietetics. The 
therapeutist also takes cognizance of hygiene, that department of 
medicine which respects the preservation of health. 
J Pharmacy (from ddfi/iatmv, pharmakon, a drug) is the generic name 
for the operations of preparing or compounding medicines, whether 
performed by the Medical Practitioner or by the Chemist and Drug- 
gist. It is also sometimes applied, like the corresponding term “ Sur- 
gery,” to the apartment in which the operations are conducted. THE ELEMENTS. 
15 
Air, water, food, drugs, and chemicals, in short all material 
substances, are composed of a few elements. An intimate 
knowledge of the properties of these, and of the various sub- 
stances they form by combining with each other, a knowledge 
of the power or force (the chemical force, or chemical affinity) 
by which the elements contained in those compounds are held 
together, and an application of such knowledge to Pharmacy 
and Medicine, must be the objects sought to be attained by the 
learner, for whom this work has been especially written. 
The Elements.—Of the sixty-seven known elements thirty- 
nine are of medical or pharmaceutical interest; of these, about 
two-thirds are metals, and one-third non-metals; the remainder* 
are so seldom met with in nature as to have received no prac- 
tical application either in medicine, art, or manufacture. Be- 
fore intimately studying the elements, it is desirable to acquire 
some general notions concerning them : such a procedure will 
also serve to introduce the practical student to his apparatus, 
and make him better acquainted with the various methods of 
manipulation.f 
Metallic Elements.—With regard to the metallic elements, it 
may be safely assumed that the reader has sufficient knowledge 
for present purposes; but little, therefore, need now be said 
respecting them. He has an idea of the appearance, relative 
weight, hardness, etc., of such metals as gold, silver, copper, 
lead, tin, zinc and iron. If he has not a similar knowledge 
of mercury, antimony, arsenicum, platinum, nickel, aluminium, 
magnesium, potassium, and sodium, he should commence his 
studies by seeing and handling specimens of each of these 
metals. 
Non-Metallic Elements—With regard to the non-metallic 
* A complete list of the elements will be found at the end of the volume. 
fThis allusion to apparatus need not discourage the youngest pupil. 
With the aid of a few phials, wine-glasses, or other similar vessels 
always at hand, he may, by studying the following pages, learn the 
chemical reactions which are constantly occurring in the course of 
making up medicines, understand the process by which medicinal 
preparations are manufactured, and detect adulterations, impurities, 
or faults of manufacture. Among the substances used in medicine, 
will be found nearly all the chemicals required. If, in addition, a 
dozen test-tubes and a few feet of glass tubing be procured, many of 
the experiments described may be performed. For full lists of appa- 
ratus and chemicals see introductory pages. 
X These bodies are sometimes termed metalloids (from fieraXXov, 
metallm, a metal, and elder, eidos, likeness); but the name is not ap- 
propriate, for the non-metallic elements have no likeness to metals. 16 
NON-M ETALLIC ELEMENTS. 
elements, it is here supposed that the student has no general 
knowledge. He should commence his studies therefore by a 
series of operations as follows, on eight out of their number. 
OXYGEN. 
Preparation.—As oxygen is the most abundant element in nature, 
forming, though in a combined state, about one-half of the whole 
weight of our globe, it may safely be assumed that this element can 
readily be obtained in the free condition in a state of purity. In 
fact, the air itself contains about one-fifth of its bulk of oxygen, 
though from the air it cannot be separated, at least not easily and 
readily, for experimental purposes. It is preferable to apply heat 
—that force which will often be noticed as antagonistic, so to speak, 
to chemical union; heat generally separating particles of matter 
further from each other, while chemical attraction tends to bind 
them closer together—it is better to heat certain compounds con- 
taining oxygen; the latter is then evolved in its normal, natural 
condition of gas. Several substances, when heated, yield oxygen; 
but for convenience and economy, the crystalline body known as 
chlorate of potassium is best fitted for the experiment. The size 
and form of the vessel in which to heat it will mainly depend on the 
quantity required; but for the purposes of the student the best is a 
test-tube, an instrument in constant requisition in studying practical 
chemistry. It is simply a thin tube of glass, a few inches in length, 
and half or three-quarters of an inch in diameter, closed by fusion 
at one end. It is made of thin glass, in order that it may be rapidly 
heated or cooled without risk of fracture. (See Fig. 1.) 
Outline of the Process.—Heat chlorate of potassium (say, as 
much as will lie on a shilling) in a test-tube, by means of a 
spirit- or gas-flame ; gaseous oxygen is quickly envolved. Be- 
fore applying heat, however, provision should be made for col- 
lecting the gas. (See Fig. 3.) 
Collection of Gases.—Procure a piece of glass tubing about 
the thickness of a quill pen, and a foot or eighteen inches long, 
and fit it accurately to the test-tube by means of a cork. 
(Longer tubes may be neatly cut to any size by smartly draw- 
ing the edge of a triangular file across the glass at the re- 
quired point, then clasping the tube, the scratch being between 
the hands, and pulling the portions asunder, force being ex- 
erted in a slightly curved direction so as to open out the crack 
which the file has commenced.) The tube is fixed in the cork 
through a round hole made by the aid of a red-hot wire, or, 
better, a rat-tail file, or, best of all, by one of a set of cork- 
borers—pieces of brass tubing sharpened at one end and hav- 
ing a flat head at the other. Setting aside the test-tube for a 
few minutes, proceed to bend the long piece of tubing to the 
most convenient shape for collecting the gas. OXYGEX. 
17 
To Bend Glass Tabes.—Hold the part of the tube required 
to be bent in any gas- or spirit-flame (a fish-tail gas-jet answers 
Fig. 1. 
Softening and bending Glass Tubes. 
very well), constantly rotating it, so that about an inch of the 
glass becomes heated. It will soon be felt to soften, and will 
then, yielding to the gentle pressure 
of the fingers, assume any required 
angle. In the present case, the tube 
should be heated at about four inches 
from the extremity to which the cork 
is attached, and bent to an angle of 
about 90 degrees. 
Source of Heat.—The source of heat 
for the test-tube may be the flame of 
an ordinary spirit-lamp, or, still better 
where coal-gas is procurable, a mixture 
of the latter with air. Gas-lamps espe- 
cially constructed to burn a mixture of 
coal-gas and air are sold by chemical- 
apparatus manufacturers. (See Figs. 
3 and 7). 
Collection, etc. (continued).— Fit 
the cork and bent tube into the test- 
tube ; the apparatus will then be 
ready for delivering gas at a convenient distance from the 
heated portion of the arrangement. To collect it, have ready 
three or four test-tubes (or small wide-mouthed bottles) filled 
with water, and inverted in a basin, or other similar vessel, 
also containing water, taking care to keep the mouths of the 
tubes a little below the surface. Now apply heat to the chlo- 
rate contained in the test-tube, and so arrange the open end of 
the bent tube under the water that the gas which presently 
issues may bubble into and gradually fill the inverted test-tubes. 
The first tubeful may be rejected, as it probably consists of 
little more than the air originally in the apparatus, and which 
has been displaced by the oxygen. That which comes after- 
wards will be pure oxygen. 
Fig. 2. 18 
NON-METALLIC ELEMENTS. 
Fig. 3. 
T]>is engraving represents the preparation, collection, and storage of small quantities 
of oxygen gas. A test-tube and bent glass tube, joined together by a perforated cork, 
are supported by the arm of an iron stand. (The apparatus might be held by the 
fingers.) The tube is heated by a gas-lamp. (The spirit-lamp shown at the back might 
be used instead.) Gas evolved from the heated substance in the test-tube is displacing 
water from an inverted test-tube. Spare tubes in a test-tube rack are at hand, and tubes 
already filled are set aside till wanted. A nest of cork-borers, a round file, a triangular 
file, and a test-tube cleaning brush are lying on the table or student’s bench. Below are 
cupboards for apparatus, above are bottles containing testing liquids, etc. 
As each tube or bottle becomes full, its mouth (still under 
the surface of the water) may be closed by a cork and set OXYGEN. 
19 
aside; or a little cup (such as a porcelain crucible or small 
gallipot) may be brought under the mouth, and the cup, with 
the mouth of the tube in it, be lifted out of the water and 
placed close by till wanted, the water remaining in the cup 
effectually preventing the gas from escaping. 
On the large scale, oxygen may be made in the same way, larger 
vessels (glass flasks or iron bottles) being employed. Less heat also 
will be necessary if the chlorate of potassium be previously mixed 
with very fine sand, or, still better, with about an equal weight of 
common black oxide of manganese. 
Note on the Collection and Storage of Gases.—It may be as well 
to state that nearly all gases, whether for experimental or practical 
purposes, are collected and stored in a similar manner. Even coal- 
gas is generated at gas-works in iron retorts very much the shape of 
test-tubes, only they are as many feet long as a test-tube is inches: 
and the well-known gigantic gas-holders may be viewed as inverted 
iron test-tubes of great diameter. 
Properties.—Oxygen is a colorless gas. Cailletet and Pictet 
succeeded in liquefying it. Wroblewski and Olszewski have 
obtained it in some amount as a definite, colorless, transparent 
fluid. Obviously it is not very soluble in water, or it could 
not be collected by the aid of that liquid. 
Oxygen is soluble to a certain extent, however (about 3 volumes 
in 100 at common temperatures), or fishes could not breathe. 
Other noticeable features are its want of taste and smell. 
Next, to show the relation of oxygen to combustion, remove 
one of the tubes from the water by placing the thumb over 
its mouth, apply for a second a lighted wood match to the 
orifice; the gas will be found to be incombustible. Extin- 
guish the flame of the match, and then quickly introduce the 
still incandescent carbonaceous extremity of the wood half- 
way down the test-tube ; the wood will at once burst into flame 
owing to the extreme violence with which oxygen supports 
combustion. These tests of the presence of oxygen may also 
be applied at the extremity of the delivery-tube whilst the gas 
is being evolved. (It is desirable to retain two tubes of the 
gas for use in subsequent experiments; also one tube in which 
only one-third of the water has been displaced by oxygen.) 
Relation of Oxygen to Animal and Vegetable Life.—Not only the 
carbon at the end of a piece of charred wood, hut any other sub- 
stance that will burn in air (which, as will be seen presently, is 
diluted oxygen) will burn more brilliantly in pure oxygen. The 
warmth of the body of animals is kept up by the continuous burn- 
ing of the tissues in the oxygen (of the air) drawn into the system 20 
NON-METALLIC ELEMENTS. 
through the lungs. The product of this combustion is a gaseous 
compound of carbon and oxygen termed carbonic acid gas, a gas 
which, in sunlight, is decomposed in the cells of plants, with fix- 
ation of the carbon and liberation of the oxygen; hence the atmo- 
sphere is kept constant in composition. 
Memorandum.—At present it is not advisable that the reader 
should trouble himself with the consideration of the chemical action 
which occurs either in the elimination of oxygen from its compounds, 
or in the separation of any of the following non-metallic elements 
from their combinations. It is to the properties of the elements 
themselves that he should restrict his attention. Working thus from 
simple to more complex facts, he will in due time find that the com- 
prehension of such actions as occur in the preparation of these few 
elements will be easier than if he attempted their full study now. 
HYDROGEN. 
Preparation and Collection.—The element hydrogen is also 
a gas,* and is obtainable from its commonest compound, water 
(of which one-ninth by weight is hydrogen), by the agency 
of hot zinc or iron, but more conveniently by the action of 
either of these metals on cold diluted sulphuric acid. The 
apparatus used for making oxygen may be employed for this 
experiment; but no lamp is required. Place several pieces of 
thin zinc f in the generating-tube (Fig. 4), or in any common 
glass bottle (Fig. 5) or flask, and cover them with water. The 
collecting-tubes (these may be wide-mouthed bottles) being 
ready, add strong sulphuric acid (oil of vitriol) to the zinc and 
wTater, in the proportion of about one volume of acid to five of 
water, and fit on the delivery-tube, or pour the acid down such 
a funnel-tube J as is shown in Fig. 5 ; the hydrogen is at once 
* Graham obtained alloys of hydrogen with palladium and other 
metals, compounds in which several hundred times its bulk of gas 
is retained by the metal in vacuo or even at a red heat. This was 
physical confirmation of the opinion long held by chemists, that 
hydrogen is a gaseous metal. Graham termed it hydrogenium (other 
chemists hydrium), and considered its relative weight in the solid state 
to be nearly three-fourths that of water. Cailletet and Pictet have 
since actually liquefied and solidified this element. 
f The best form is granulated zinc (Zincum, U. S. 1\), made by heating 
scraps of common sheet zinc in a ladle over a fire, and as soon as 
melted pouring, in a slow stream, into a pail of water from a height 
of 8 or 10 feet. Each drop of zinc thus yields a thin little bell, which, 
for its weight, presents a large surface to the action of the acid water. 
If the zinc is allowed to become hotter than necessary, the little bells 
will not be formed. 
J Funnel-tubes may be purchased of the apparatus-maker, or, if the 
pupil has access to a table blowpipe and the advantage of a tutor to 
direct his operations, they may be made by himself. HYDROGEN. 
evolved. Having rejected the first portions (or having waited 
until the air originally in the bottle may be considered to be 
all expelled), collect four or five tubes of the gas in the manner 
described under Oxygen. 
Fig. 4. 
Fig. 5. 
Preparation of Hydrogen. 
In making larger quantities bottles of appropriate size may be 
employed. 
Other metals, notably potassium and sodium, liberate hydrogen 
the moment they come into contact with water; but the processes 
are not economical. 
Properties.—Like oxygen, hydrogen gas is invisible, inodor- 
ous, and tasteless. If made with iron it has a strong smell, 
hut this is due to impurities derived from the iron. 
Apply a flame to the mouth of the delivery-tube (care being 
taken that the gas is coming off- briskly—a guarantee that no 
air remains in the generating vessel) ; ignition of the hydrogen 
ensues, showing that, unlike oxygen, it is combustible. 
Plunge a lighted match well into a tube (or wide-mouthed 
bottle) containing hydrogen ; the.gas is ignited, hut the match 
becomes extinguished. This shows that hydrogen is not a sup- 
porter of combustion. 
Hydrogen in burning unites with the oxygen of the air and 
forms water, which may be condensed on a cool glass or other 
surface. Prove this by holding a glass vessel a few inches 
above a hydrogen flame. In burning the hydrogen contained 
in one of the tubes or bottles, the flame is best seen when the 
tube is held mouth upwards, and water poured in so as to force 
out the gas gradually. 
If, instead of this gradual combination of the two elements 
oxygen and hydrogen, they be mixed together in bulk in the 
right proportions and then ignited, they will rapidly combine, 22 
NON-M ETA LLIC El. EM ENTS. 
and explosion will result. Prepare a mixture of this kind by 
filling up with hydrogen a test-tube from which one-third of 
the water has been expelled by oxygen. Iiemove the tube from 
the water, placing a finger over the mouth, and, having a 
lighted match ready, apply the flame ; a slight explosion ensues, 
owing to the instantaneous combination of the two elements, 
and the expansive force of the highly heated steam produced. 
If anything larger than a test-tube is employed in this experi- 
ment, it should be a soda-water bottle, or some such vessel 
equally strong. 
These two gases thus unite at a temperature far higher than that 
of boiling water, two volumes of hydrogen and one of oxygen yield- 
ing two volumes of gaseous water (true steam). 
The noise of such explosions is caused by concussion between the 
suddenly expanded gaseous body and the air. 
The force of the explosion, or, in other words, the force of the 
suddenly heated, and therefore suddenly expanded, steam, is below 
that necessary to break the test-tube. Some force, however, is ex- 
erted, and hence the necessity of the precaution previously suggested 
of allowing all the air which may be in a hydrogen-apparatus to 
escape before proceeding with the experiments. If a flame be ap- 
plied to the delivery-tube before all the air is expelled, the probable 
result will be ignition of the mixture of hydrogen and oxygen (of 
the air) and consequent explosion. But even in this case the gen- 
erating-vessel is not often fractured unless it be large and of thin 
glass, the ordinary effect being that the cork is blown out, and the 
delivery-tube broken on falling to the ground. 
Hydrogen is a prominent constituent of all the substances used 
for producing artificial light, such as tallow, oil, and coal-gas. The 
explosive force of large quantities, such as a roomful of coal-gas and 
air, though vastly beloAV that of an equal weight of gunpowder, is 
well known to be sufficient at least to blow out that side of the room 
which offers least resistance. 
The composition of water can be proved analytically as well as 
synthetically, a current of electricity decomposing it into its con- 
stituent gases, twice as much hydrogen as oxygen, by volume, being 
produced. 
Combustion (from comburo, to burn).—The experiments with 
hydrogen and oxygen illustrate the true character of combustion. 
Whenever chemical combination is sufficiently intense to be accom- 
panied by heat and light, the materials are said to undergo combus- 
tion. Combustion only occurs at the line of contact of the combin- 
ing bodies ; a jet of oxygen will burn in an atmosphere of hydrogen 
quite as easily as a jet of hydrogen in oxygen. A jet of air (diluted 
oxygen) will burn as readily in a jar of coal-gas as a jet of coal-gas 
burns in air; each is combustible, each supports the combustion of 
the other. Hence the terms combustible and supporter of combus- 
tion are purely conventional, and only applicable so long as the cir- 
cumstances under which they are applied remain the same. In the HYDROGEN. 
23 
case of substances burning in air, the conditions are, practically, 
always the same: hence no confusion arises from regarding air as 
the great supporter of combustion, and bodies which burn in it as 
being combustible. 
Structure of Hume.—A candle-flame or oil-flame is a jet of gas 
intensely heated ; the central portion is unburnt gas ; the next enve- 
lope is formed of partially burnt and very dense, gaseous, and solid 
particles sufficiently highly heated to give light, and the outer cone 
of completely burnt gases. In the figure the sharpness of limit of 
these cones is purposely somewhat exaggerated. Air made, by any 
mechanical contrivance of burner, to mix with the interior of a flame 
at once burns up, or perhaps prevents the formation of dense gases 
giving a hotter, but non-luminous, jet. The air-gas lamps (Fig. 7), 
or “ Bunsen ” gas-burners commonly used in chemical laboratories 
are constructed on this principle ; their flame has the additional ad- 
vantage of not yielding a deposition of soot. 
Fig. 6. 
Fig. 7. 
Structure of Flame. 
In the air-gas lamp, coal-gas escaping from a small orifice draws 
rather more than twice its volume of {fir (supplied through adjacent 
holes) into its column, and the mixture of gas and air passes upwards 
along a pipe. It only burns at the end, and not within the pipe, 
partly because the metal of the burner, by conducting heat away, 
cools the mixture below the temperature at which it can ignite; 
partly because the velocity with which the mixture flows out is 
greater than the rate at which such a mixture ignites; and partly 
because the proportion of air to gas in this mixture is insufficient 
for thorough and perfect combustion, the external air contributing 
materially to the complete combustion of the jet of air-gas. The 
Davy safety-lamp acts on the first-named principle; a wire-gauze 
cage surrounds an oil-flame; an inflammable mixture of gas and air 
(fire-damp) can pass through the gauze and catch fire and burn in- 
side ; but the flame cannot be communicated to the mixture outside, 
because the metal of the gauze and of the other parts cools down the 
gas below the temperature at which combustion can continue. 
“ Bunsen ” or Air-gas Burner 24 
NON-METALLIC ELEMENTS. 
Properties (continued).—Gaseous hydrogen is the lightest 
substance known. It was formerly used for filling balloons, 
but was superseded by coal-gas. Coal-gas is not so light as 
hydrogen, but is cheaper and more easily obtained. The light- 
ness of hydrogen may be rendered evident by the following 
experiment: Fill two test-tubes with the gas, and hold one 
with its mouth downwards and the other with its mouth up- 
wards. The hydrogen will have escaped from the latter in a 
few seconds, whereas the former will still contain the gas after 
the lapse of some minutes. This may be proved by applying 
a lighted match to the mouths of the respective tubes. 
The relative weight or specific gravity of oxygen is sixteen times 
that of hydrogen. A vessel holding one grain of hydrogen will hold 
sixteen grains of oxygen. The relation of the weight of hydrogen 
to air is as 1 to 14.44 or as 0.0693 to 1.0. One grain of hydrogen by 
weight would measure about 27 fluidounces. One grain of hydrogen 
would, therefore, about fill a common wine bottle. Such a bottle 
would hold about 14| grains of air, or 16 grains of oxygen. 
Mem.—It is desirable to retain two tubes of hydrogen for use in 
subsequent experiments. 
Diffusion of Gases.—Hydrogen cannot be kept in such vessels as 
the inverted test-tubes ; for, though much lighter than air, it diffuses 
downwards into the air, while the air, though much heavier, diffuses 
upwards into the hydrogen. This power of diffusion is character- 
istic of all gases, and proceeds according to a fixed law, namely, “ in 
inverse proportion to the square root of the specific gravity of the 
gas ” (Graham). Thus hydrogen diffuses four times faster than 
oxygen. This great and important property of diffusion strongly 
suggests that the particles of gases, at least, are always moving, 
never at rest; how otherwise could gases diffuse into each other, as 
they do, notwithstanding the opposing influence of gravitation? 
Diffusion strongly supports this (Clausius’s) Kinetic (niveu, kineo, I 
move or put in motion) theory of the physical condition of gases. 
PHOSPHORUS. 
Appearance and Source.—Phosphorus (Phosphorus, U. S. P.) is 
a solid element, in appearance and consistence resembling white 
wax; but it gradually becomes yellow by exposure to light. It 
is a characteristic constituent of bones, and is always prepared 
from that source by a process which will be subsequently de- 
scribed. 
Caution.—Phosphorus, on account of its great affinity for oxygen, 
takes fire very readily in the air, and should therefore be kept under 
water. When wanted for use it must be cut under water. It is 
employed in tipping lucifers, though red or amorphous phosphorus 
(ivide Index) is least objectionable for this purpose. 
Experiment.—Dry a piece about one-fourth the size of a pea 
by quickly and carefully pressing it between the folds of porous NITROGEN'. 
25 
(filter or blotting) paper; place it on a plate, and ignite by 
touching it with a piece of warm wire or wood. The product 
of combustion is#a dense white suffocating smoke, which must 
be confined at once by placing an inverted tumbler, test-glass, 
or other similar vessel over the phosphorus. The fumes rapidly 
aggregate, and fall in white flakes on the plate. When this 
has taken place, and the phosphorus is no longer burning, 
moisten the powder with a drop or two of water, and observe 
that some of the water is converted into steam, an effect due 
to the intense affinity with which the two combine. 
The powder produced by the combustion of phosphorus is phos- 
phoric anhydride; the combination of the latter with the elements 
of water produces a variety of phosphoric acid which dissolves in 
the water, forming on standing a dilute solution of ordinary phos- 
phoric acid. The Diluted Phosphoric Acid of the British and United 
States Pharmacopoeias is a somewhat similar solution, made, how- 
ever, in a different way, and of a definite strength. 
NITROGEN 
Source.—The chief source of this gaseous element is the atmo- 
sphere, nearly four-fifths of which consists of nitrogen (the remaining 
fifth being almost entirely oxygen). 
Preparation.—Burn a piece of dried phosphorus, the size 
of a pea, in a confined portion of air. The oxygen is thus re- 
moved. and nitrogen alone remains. The readiest mode of 
performing this experiment is to fix a piece of earthenware 
Fig. 8. 
Fig. 9. 
Preparation of Nitrogen. 
Decantation of Oases. 
(the lid of a small porcelain crucible answers very well) on a 
thin piece of cork, so that it may float in a dish of water. Place 
the phosphorus on the lid, ignite by a warm rod, and then in- 
vert a tumbler, or any glass vessel of about a half-pint capacity, 
over the burning phosphorus, so that the glass may dip into the 26 
NON-META LUC ELEMENTS. 
water. Let the arrangement rest for a short time for the fumes 
of phosphoric anhydride to subside and dissolve in the water, 
and then decant the gas into test-tubes in the manner indi- 
cated in Fig. 9, using a tub or other vessel of water of suffi- 
cient depth to permit the glass containing the nitrogen to be 
turned on one side without air gaining access. 
Larger quantities of nitrogen are made in the same way. Other 
combustibles, such as sulphur or a candle, might be used to burn out 
the oxygen from a given quantity of air, but none answer so quickly 
and completely as phosphorus : added to which, the product of their 
combustion would not always be dissolved by water, but would re- 
main with and contaminate the nitrogen. 
Mem.—The statement concerning the composition of the air is 
roughly confirmed in preparing nitrogen, about one-fifth of the vol- 
ume of the air originally in the glass vessel having disappeared, its 
place being occupied by water from the dish. 
Properties.—Like oxygen and hydrogen, nitrogen gas is in- 
visible, tasteless, and inodorous. By pressure Cailletet and 
Pictet succeeded in condensing it to a liquid. Wroblewski and 
Olszewski have obtained it in some amount as a definite, color- 
less, transparent fluid. It is only slightly soluble in water. 
Free nitrogen is distinguished from all other gases by the 
absence of any characteristic or positive properties. Apply a 
flame to some contained in a tube ; it will be found to be incom- 
bustible. Immerse a lighted match in the gas; the flame is 
extinguished, showing that nitrogen is a non-supporter of 
combustion. 
The chief office of nitrogen in the air is to dilute the energetic 
oxygen, a mere mechanical mixture resulting. 
Nitrogen is fourteen times as heavy as hydrogen. 
The air is nearly fourteen and a half (14.44) times as heavy as 
hydrogen. Its average composition, including minor constituents, 
which will be referred to subsequently, is as follows:— 
Composition of the Atmosphere. 
In 100 volumes. 
Oxygen 20.61 
Nitrogen 77.95 
Carbonic acid gas .04 
Aqueous vapor 1.40 
Nitric acid 
Ammonia 
Carburetted hydrogen 
traces. 
%) ~ 
Sulphuretted hydrogen 
Sulphurous acid 
traces in 
towns. 
The above proportions are by volume. By weight there will he 
nearly 23 parts of oxygen to nearly 77 of nitrogen, oxygen being CHLORINE. 
27 
the heavier in the ratio of 16 to 14. Ozone (ride Index) is also said 
to be a normal constituent of air. 
The comparative inactivity or negative character of nitrogen in its 
free condition, that is, when uncombined with other elements, con- 
trasts strongly w'ith its apparent influence in a state of combination. 
IV hen its compounds with hydrogen come to be studied, it will be 
found to be, apparently, the chiel, or leading, or, in a sense, the 
most important element of those compounds—the ammoniacal com- 
pounds. United with carbon it gives the poisonous cyanic sub- 
stances. With oxygen it gives quite a large group of bodies, 
amongst which are the common and important class of salts termed 
nitrates. With carbon as well as hydrogen and some oxygen it 
affords powerful agents termed alkaloids—near relatives of" ammo- 
nia—while the same elements otherwise grouped, with sometimes a 
little sulphur or phosphorus, form the various albumenoid and gel- 
atinoid matters characteristic of the tissues of animals and veg- 
etables. In a perfect structure we should perhaps scarcely regard 
any one element or member as more important than another, still 
such a conclusion almost forces itself upon us as we become ac- 
quainted with the chemical history of combined nitrogen. 
CHLORINE. 
Source.—This element is a gas. Its chief source is common salt, 
more than half of which is chlorine. 
Preparation.—About a quarter of an ounce of salt and the 
same amount of black oxide of manganese are mixed, and 
placed in a test-tube with sufficient water to cover them ; on 
adding a small quantity of sulphuric acid, the evolution of 
chlorine commences. For mode of collection see following 
paragraphs. 
Fig. 10. 
Fig. 11. 
Preparation of Chlorine. 
Another Process.—As the action of the sulphuric acid on the salt 
in the above process is mainly to give hydrochloric acid, the latter 28 
NON-METALLIC ELEMENTS. 
acid (about 4 parts) and the black oxide of manganese (about 1 part) 
may be used in making the gas, instead of salt, sulphuric acid, and 
black oxide of manganese. This, the usual process, is that adopted 
in the British and United States Pharmacopoeias. 
Collection and Properties.—Chlorine is a most suffocating gas. 
Great care must consequently be observed in experimenting 
with this element. As soon as its penetrating odor indicates 
that it is escaping from the test-tube, the cork and delivery- 
tube (similar to that used in making oxygen) should be fitted 
on, and the gas allowed to pass to the bottom of another test- 
tube containing water (Fig 10). When thirty or forty small 
bubbles have passed, their evolution being assisted by slightly 
heating the generating-tube, the latter should be removed to 
the cupboard usually provided in laboratories for performing 
operations with noxious gases, or dismounted, and the con- 
tents washed away. The water in the collecting-tube will now 
be found to smell of the gas, chlorine being, in fact, soluble in 
about half its bulk of water. Chlorine-water is official* in 
the United States Pharmacopoeia (Aqua Chlori, U. S. P.). 
Larger quantities may be made from hydrochloric acid and black 
oxide of manganese (about 4 parts to 1) in a Florence flask, fitted 
with a delivery-tube, the flask being supported over a flame by the 
ring of a retort-stand or any similar mechanical contrivance (Fig. 
11). A piece of cardboard on the neck of the collecting-bottle, as 
indicated in the figure, retards diffusion of the gas from the bottle 
during collection of the gas. 
Mem.—Flasks and similar glass vessels are less liable to fracture 
if protected from the direct action of the flame by being placed on 
a piece of wire gauze 3 to 4 inches square, or on a sand-bath, that 
is, a saucer-shaped tray of sheet iron, on which a thin layer of sand 
is placed. 
* The Pharmacopoeia and all in it are official {office, Fr., from L. 
offici.um, an office). There are many things which in pharmacy are 
officinal (Fr., from L. officina, a shop) but not official. To restrict the 
word officinal to the contents of a pharmacist’s shop and to that por- 
tion of the contents which is Pharmacopoeial, is radically wrong, and 
should be avoided. “An official formula is one given under authority. 
An officinal formula is one made in obedience to the customary usage 
of the shop {officina). To state that any preparation under the sanc- 
tion of the Pharmacopoeia is officinal, is a misapprehension of the 
meaning of the word.”—J. Brough. 
That is official which emanates from a recognized authority. That 
is officinal which is issued from an officina or workshop —Joseph Inee. 
Official writings and orders are those issued by official persons. 
Officinal articles are such as are found in a shop.—J. F. Stanford, 
M.A., F.R.S. CHLORINE. 
29 
The T npor Chlori, B. P., or Inhalation of Chlorine, is simply 
moist chlorinated lime so placed that some of the chlorine given off 
may be inhaled. 
During these manipulations the operator will have noticed that 
chlorine is of a light-green color. That tint is readily observed 
when the gas is collected in large vessels. As it is soluble in water 
(2£ vols. in 1 vol. at 60° F.), it cannot be economically stored over 
that liquid. Being, however, nearly twice and a half as heavy as 
air, it may be collected by simply allowing the delivery-tube to pass 
to the bottom of the test-tube or dry bottle (Fig. 11). 
The distinctive property of chlorine is its bleaching power. 
Prepare some colored liquid by placing a few chips of logwood 
or other dyeing material in a test-tube half full of hot water. 
Pour off- some of this red decoction into another tube and add 
a few drops of the chlorine-water; the red color is rapidly 
destroyed. 
Chlorine readily decomposes offensive effluvia; it is one of the 
most powerful of the deodorizers. It also decomposes putrid and 
infectious matter; it is one of the best of disinfectants. (Antisep- 
tics are substances which prevent putrefaction. See Index.) 
Combination of Hydrogen with Chlorine, forming Hydro- 
chloric Acid.—If an opportunity occurs of generating the gas 
in a closed chamber or in the open air, a test-tube, of the same 
size as one of those in which hydrogen has been retained from 
a previous operation, is filled with the gas. The hydrogen 
tube is then inverted over that containing the chlorine, the 
mouths being kept together by encircling them with a finger. 
After the gases have mixed, the mouths of the tubes are 
quickly in succession brought near a flame, when explosion 
occurs, and fumes of a compound of hydrochloric acid with 
the moisture of the air are formed. The Hydrochloric Acid 
of Pharmacy {Acidam Hydrochloricnm, U. S. P.) is a solution 
of the gas (made in a more economical way) in water. 
The foregoing experiment affords evidence of the powerful affinity 
of chlorine and hydrogen for each other. Chlorine dissolved in 
water will, in sunlight, slowly remove hydrogen from some of the 
water and liberate oxygen. The bleaching power of chlorine is 
generally referred to this oxidizing effect which it produces in pres- 
ence of water; for dry chlorine does not bleach. 
Density.—Chlorine is thirty-five and a half times as heavy as 
hydrogen. A wine bottle would hold about 354 grains. 30 
NON-METALLIC ELEMENTS. 
The physical properties of these elements (color, hardness, weight, 
etc.) are familiar. Their leading chemical characters will also be 
understood when a few facts concerning each are made the subject 
of experiment. 
SULPHUR, CARBON, IODINE. 
Sulphur.—Burn a small piece of sulphur; a penetrating 
odor is produced, due to the formation of a colorless gas, the 
same as that formed on igniting a sulphur-tipped lucifer match. 
This product is a perfectly definite chemical compound of the oxy- 
gen of the air with the sulphur. It is termed sulphurous anhydride 
or sulphurous acid gas. 
Carbon is familiar in the forms of soot, coke, charcoal, 
graphite (or plumbago, popularly termed blaeklead), and dia- 
mond. The presence of carbon in wood, and in other vege- 
table and animal matter, is at once rendered evident by heat. 
Place a little tartaric acid on the end of a knife in a flame; 
the blackening that occurs is due to the separation of carbon. 
The black matter at the extremity of a piece of half-burned 
wood is- also carbon. 
Carbon, like hydrogen, phosphorus, and sulphur, has a great 
affinity for oxygen at high temperatures. A striking evidence of 
that affinity is the evolution of sufficient heat to make the materials 
concerned red or even white hot. When ignited in the dilute oxy- 
gen of the air, carbon simply burns with a moderate glow, as seen 
in an ordinary coke or charcoal fire, but when ignited in pure oxy- 
gen, the intensity of its combination is greatly exalted. The prod- 
uct of the combination of the two elements, if the oxygen be in 
excess, is an invisible gaseous body termed carbonic acid gas; if 
the carbon be in excess, another invisible gas termed carbonic oxide 
results. 
Iodine.—A prominent chemical characteristic of iodine is 
its great affinity for metals. Place a piece of iodine, about 
the size of a pea, in a test-tube with a small quantity of water, 
and add a few iron-filings or small nails. On gently warming 
this mechanical mixture, or even shaking if longer time be 
allowed, the color and odor of the iodine disappear: it has 
chemically combined with the iron : a chemical compound has 
been produced. If the solution be filtered, a clear aqueous 
solution of the compound of the two elements is obtained. 
This compound is an iodide of iron. Its solution, made as above, 
and mixed with sugar, forms, when of a strength of 10 per cent., the 
ordinary Syrup of Iodide of Iron of pharmacy (Syrupus Ferri Iodidi, 
U. S. I’.). A strong solution mixed with sugar, glycyrrhiza, gum, THE ELEMENTS, THEIR SYMBOLS, ETC. 
31 
etc., constitutes the corresponding Pill (Pit vice Ferri Iodidi, U. S. 
P.). The solid iodide (Ferri Iodidum, B. P.) is obtained on remov- 
ing the water of the above solution by evaporation. 
Sulphur and Iron, also, when very strongly heated, chemically 
combine to form a substance which has none of the properties of a 
mixture of sulphur and iron—that is, has none of the characters of 
sulphur and none of iron, but new properties altogether. The prod- 
uct is termed Sulphide of Iron. Its manufacture and uses will be 
alluded to in treating of the compounds of iron 5 it is mentioned 
here as a simple but striking illustration of the difference between a 
chemical compound and a mechanical mixture. 
TIIE ELEMENTS, THEIR SYMBOLS, Etc 
From the foregoing statements a general idea will have been ob- 
tained of the nature of several of the more frequently occurring 
elements. Some additional facts concerning them may be gathered 
from the following Table, which gives the name in full, the symbol 
(or short-hand character)* of the name, and its origin. 
For the purposes of study the elements may be divided into three 
classes—viz., those frequently used in pharmacy, those seldom, and 
those never used. 
Name. 
Symbol. 
Derivation of Name. 
Oxygen .... 
0 
From oft'f (oxus), acid, and ylveatc (gen- 
esis), generation, i. e., generator of acids. It 
was supposed to enter into the composition 
of all acids when first discovered. 
Hydrogen . . . 
ir 
From vduf) (hudor), water, and yivecu; 
(genesis), generation, in allusion to the 
product of its combination in air. 
Nitrogen .... 
N 
From virgov (nitron), and ytve.au; (genesis), 
generator of nitre. 
Carbon 
C 
From carbo, coal, which is chieflv carbon. 
Chlorine .... 
Cl 
From xAupoc (ehloros), green, the color of 
this element. 
Iodine 
I 
From iov (ion), a violet, and thine (eidos), 
likeness, in reference to the color of its 
vapor. 
Sulphur .... 
s 
From sal, a salt, and nig (pur), fire, in- 
dicating its combustible qualities. Its com- 
mon name, brimstone, has the same meaning, 
being the slightly altered Saxon word bryn- 
stone, i. e., burnstone. 
Phosphorus . . . 
p 
(pen; (phds), light, and tpepetv (pherein), to 
bear. The light it emits may be seen on 
exposing it in a dark room. 
* The symbol is also much more than the short-hand character, as 
will be presently apparent. 32 
THE ELEMENTS, THEIR SYMBOLS, ETC. 
Name. 
Symbol. 
Derivation of Name. 
Potassium . . . 
(Kalium.) 
K 
Kalium, from kali, Arabic for ashes. Man- 
ufactories in which certain compounds of 
potassium and allied sodium salts are made 
are called alkali-works to this day. Potas- 
sium, from pot-ash; so called because ob- 
tained by evaporating the lixivium of wood- 
ashes in pots. From such ashes the element 
was first obtained, lienee the name. 
Sodium .... 
(Natrium.) 
Na 
A atrium, from natron, the old name for 
certain natural deposits of carbonate of 
sodium. Sodium, from soda-ash or sod-ash, 
the residue of the combustion of masses or 
sods of marine plants. These were the 
sources of the metal. 
Ammonium . . . 
Am 
(NH4) 
This body is not an element; but its 
components exist in all ammoniacal salts, 
and apparently play the part of such el- 
ements as potassium and sodium. Sal 
ammoniac (chloride of ammonium) was 
first obtained from near the temple of Ju- 
piter Ammon in Libva; hence the name. 
Barium .... 
Ba 
From flapvg (barus), heavy, in allusion to 
the high specific gravity of “ heavy spar,” 
the most common of the barium minerals. 
Calcium .... 
Ca 
Calx, lime, the oxide of calcium. 
Magnesium . . . 
Mg 
From Magnesia, the name of the town (in 
Asia Minor) near which the substance now 
called “native carbonate of magnesia” was 
first discovered. 
Iron 
(Ferrum.) 
Fe 
The spelling is from the Saxon iren, the 
pronunciation probably from the kindred 
Gothic “ iarnthe derivation is Aryan ; it 
probably originally meant metal. 
Aluminium . . . 
A1 
The metallic basis of alum was at first 
confounded with that of sulphate of iron, 
which was the alum of the Romans, and 
was so called in allusion to its tonic prop- 
erties. from alo, to nourish. 
Zinc 
Zn 
From Ger. zinn, tin, with which zinc 
seems at first to have been confounded. 
Arsenicum . . . 
As 
'Apaeviuov (arsenikon), the Greek name for 
orpiment, a sulphide of arsenicum. Common 
white arsenic is an oxide of arsenicum. 
Antimony . . . 
(Stibium.) 
Sb 
Zrifti (stibi), or aripyi (stimuli), was the 
Greek name for the native sulphide of an- 
timony. The word antimony is said to be 
derived from avrl (anti, against), and moine, 
French for monk, from the fact that certain 
monks were poisoned by it. 
Copper 
(Cuprum.) 
. Cu 
From Cyprus, the Mediterranean island 
where this metal was first worked. THE ELEMENTS, THEIR SYMBOLS, ETC. 
33 
Name. 
Symbol. 
Derivation of Name. 
Lead 
(Plumbum.) 
Fb 
The Latin word is expressive of “some- 
thing heavy,” and the Saxon Iced has a 
similar signification. 
Mercury .... 
(Hydrargyrum.) 
Hg 
Hydrargyrum, from vtiup (hudor), water, 
and agyvfjog (arguros), silver, in allusion to 
its liquid and lustrous characters. Mercwy, 
after the messenger of the gods, on account 
of its susceptibility of motion. The old 
name quicksilver also indicates its ready 
mobility and argentine appearance. 
Silver 
(Argentum.) 
Ag 
'Apyvpog (arguros), silver, from apyog Car- 
gos), white. Words resembling the term 
silver occur in several languages, and indi- 
cate a white appearance. 
The following are the names of some of the less frequently 
occurring elements, compounds of which, however, are alluded 
to in the British and IT. S. Pharmacopoeias, or met with in 
pharmacy. 
Name. 
Symbol. 
Derivation of Name. 
Bromine .... 
Br 
P rom jJfj&fioc (bromcs), a stink. It has an 
intolerable odor. 
Fluorine .... 
FI 
From fluo, to flow. Fluoride of calcium, 
its source, is commonly used as a flux in 
metallurgic operations. 
Boron 
B 
From borax, or baurak, the Arabic name 
of bcrrax, the substance from which the el- 
ement was first obtained. 
Silicon 
Si 
From si lex, Latin for flint, which is nearly 
all silica (an oxide of silicon). 
Lithium .... 
L 
F'rom /itteioQ (litheios), stony, in allusion 
to its supposed existence in the mineral 
kingdom onlv. 
Strontium . . . 
Sr 
This name is commemorative of Strovtian, 
a mining village in Argyleshire, Scotland, 
in the neighborhood of which the mineral 
known as strontianile or carbonate of stron- 
tium was first found. 
Cerium 
Ce 
Discovered in 1803. and named after the 
planet Ceres, which was discovered on Jan. 
1, 1801. The oxalate of cerium is official, 
but seldom used. 
Chromium . . . 
Cr 
F'rom ypw//« (chroma), color, in allusion to 
the characteristic appearance of its salts. THE ELEMENTS, THEIR SYMBOLS, ETC. 
Name. 
Symbol. 
Derivation of Name. 
Manganese . . . 
Mn 
Probably a mere transposition and rep- 
etition of most of the letters of the word 
maynesia, with whose compounds those of 
manganese were confounded till the year 
1740. 
Cobalt 
Co 
Cobalus or Kobold was the name of a de- 
Nickel 
mon supposed to inhabit the mines of Ger- 
many. The ores of cobalt were formerly 
troublesome to the German miners, and 
hence. received the name their metallic 
radical now bears. 
Ni 
Nickel, from nil, is a popular German 
term for worthless. The mineral now known 
as nickel ore was formerly called by the 
Germans Kupfernickel, false copper, on ac- 
count of its resemblance to copper (Kupfer) 
ore. When a new metallic element was 
found in the ore, the name nickel was re- 
tained. 
Tin (Stannum) . 
Sn 
Both words are possibly corruptions of 
the old British word staen, or the Saxon 
word stan, a stone. Tin was first discovered 
in Cornwall, and the ore (an oxidfe) is called 
tinstone to the present day. 
Goid(Aurum) . . 
Au 
Anrurn (Latin), from a Hebrew word sig- 
nifying the color of fire. 
Gold. A similar worcf is expressive of 
Platinum .... 
briqht yellow in several old languages. 
Pt 
From pi at inn (Spanish), diminutive of 
plain, silver. It somewhat resembles silver 
in appearance, but is less white and lus- 
trous. 
Bismuth .... 
Bi 
Slightly altered from the German Wis- 
muth, derived from Wiesematle, “a beautiful 
meadow,” a name given to it originally bv 
the old miners in allusion to the prettily 
variegated tints presented by the freshly 
exposed surface of this crystalline metal. 
Cadmium .... 
Cd 
Kadpeia (Kadmeia), was the ancient name 
of calamine (carbonate of zinc), with which 
carbonate of cadmium was long confounded, 
the two often occurring together. 
Gold, Platinum, Tin, and Silicon are classed with the less import- 
ant elements, because their salts are seldom used in pharmacy. 
It will he noticed that the symbol of an element is simply the first 
letter of its Latin name, which is generally the same as in the Eng- 
lish. Where two names begin with the same letter, the less import- 
ant has an additional letter added. THE ELEMENTS, THEIR SYMBOLS, ETC. 
35 
1. Of how many elements is terrestrial matter composed ? 
2. In what state do the elements occur in nature? 
3. Distinguish between the art and the science of chemistry. 
4. What is the difference between an element and a compound? 
5. Enumerate the chief non-metallic elements. 
6. Describe a process for the preparation of oxygen. 
7. How are gases usually stored? 
8. Mention the chief properties of oxygen. 
9. What is the source of animal warmth ? 
10. State the proportion of oxygen in air. 
11. Is the proportion constant, and why? 
12. Give a method for the elimination of hydrogen from water. 
13. State the properties of hydrogen. 
14. Why is a mixture of hydrogen and air explosive? 
15. Explain the effects producible by the ignition of large quan- 
tities of coal-gas and air. 
16. What is the nature of combustion? 
17. Define a combustible and a supporter of combustion. 
18. Describe the structure of flame. 
19. State the principle of the Davy safety-lamp. 
20. To what extent is hydrogen lighter than oxygen? 
21. What do you mean by diffusion of gases? 
22. State Graham’s law concerning diffusion. 
23. Name the source of phosphorus, and give its characters. 
24. Why does phosphorus burn in air? 
25. What remains when ignited phosphorus has removed all the 
oxygen from a confined portion of air? 
26. Mention the properties of nitrogen. 
27. What office is fulfilled by the nitrogen of air? 
28. State the proportions of the chief constituents of air. 
29. Mention the minor or occasional constituents of air. 
30. What is the proportion by weight of nitrogen to oxygen in 
the atmosphere ? 
31. Give the specific gravity of nitrogen. 
32. llow is chlorine prepared? 
33. Enumerate the properties of chlorine. 
34. Define the terms deodorizer and disinfectant. 
35. Explain the bleaching effect of chlorine. 
36. What proportion of hydrogen to chlorine is necessary for the 
formation of hydrochloric acid gas? 
37. State the prominent physical and chemical characters of 
sulphur. 
38. State the prominent characters of carbon. 
39. State the prominent characters of iodine. 
40. Give the derivations of the names of some of the elements. 
41. What are the symbols of oxygen, hydrogen, nitrogen, carbon, 
chlorine, iodine, sulphur, phosphorus? 
QUESTIONS AND EXERCISES. 36 
GENERAL PRINCIPLES OF 
The Learner is recommended to read the following para- 
graphs on the General Principles of Chemical Philosophy 
CAREFULLY ONCE OR TWICE, THEN TO STUDY (EXPERIMENTALLY, IF 
possible) the succeeding pages, returning to and reading 
over the General Principles from time to time until they 
ARE THOROUGHLY COMPREHENDED. 
THE GENERAL PRINCIPLES OF CHEMICAL 
PHILOSOPHY. 
Definition of Chemical Action. 
The learner may now proceed to study the manner in which sub- 
stances act chemically on each other. By acting chemically it will 
be obvious, from the preceding experiments, that what is meant is 
so affecting each other that the substances are greatly altered in prop- 
erties. A mixture of oxygen and hydrogen is still a gas; a chem- 
ical compound of oxygen and hydrogen is a liquid, namely, water; 
here is a great alteration in leading properties. Iodine is only 
slightly soluble in water, and forms a brown-colored solution, and 
iron is insoluble ; but when iodine and iron are chemically combined, 
the product is very soluble in water, forming a light-green solution 
in which the eye can detect neither iodine nor iron, and which is 
utterly unlike iron or iodine in any one of their properties. Sand, 
sugar, and butter rubbed together form a mere mixture, from which 
water would extract the sugar, and ether dissolve out the butter, 
leaving the sand. Tartaric acid, carbonate of sodium, and water 
added to each other, form a chemical compound, containing neither 
tartaric acid nor carbonate of sodium, these bodies having attacked 
each other and formed fresh combinations. These illustrations show 
that chemical action is distinguished from all other actions by (a) 
producing an entire change of properties in the bodies on which it 
is exerted. Chemical action is further distinguished by (b) the fact 
that it only takes place between definite weights and volumes of 
matter. This (a and b) cannot be said of any other action—the 
action of any of the other great forces of nature (gravitation, heat, 
light, electricity, etc.); hence the statements (a and b) furnish a 
sharp and precise definition of chemical action or the chemical force, 
the force whose manifestations the reader of this book, or of any 
other manual of chemistry, is studying. 
Atoms. 
In a chemical compound, what has become of the constituents ? 
Let the reader place before him specimens of sulphur, iron, and 
sulphide of iron ; or iodine, iron, solid iodide of iron and its solu- 
tion in water or syrup (Syrupus Ferri Iodidi, U. S. P.). In the sul- 
phide of iron what has become of the sulphur and of the iron from 
which it was made ? The mixture of sulphur and iron in combining 
to form sulphide of iron has not lost weight, and, indeed, by certain 
processes it is possible to recover its sulphur as sulphur, and its iron CHEMICAL PHILOSOPHY. 
37 
as iron; so that we are compelled to believe, we cannot avoid the 
conclusion, that sulphide of iron contains particles of sulphur and of 
iron. Rut how small must be those particles! Rub a minute fra»- 
ment to dust in a mortar and place a trace of the powder under the 
ugliest power of the.best microscope; no yellow particle is visible, 
not the minutest portion of lustrous metal, but dull-brown miniature 
fragments, of the original mass. The elementary particles of sul- 
phur and iron, or of the elements in any other compound (the chlo- 
rine and sodium in common salt or the iodine and iron in solution 
or iodide of iron), are, in short, too small to be seen. Can they be 
imagined ? Again, no. The mind cannot conceive of a particle of 
anything (sulphur, iron, sulphide of iron, or what not) so small but 
what the next instant the imagination has divided it. Yet learner 
ami teacher must have some common platform on which to reason 
and converse. The difficulty is met by speaking of these inconceiv- 
ably small particles as atoms (aro/uog, atomos, invisible; from the 
privative.« and regvu, temno, to cut—that which is not cut or divided), 
an expedient suggested by our countryman Dalton at the commence- 
ment ol the present century. It is an expedient not perhaps alto- 
gether satisfactory, but is the only one possible to the majority of 
minds in the present state of knowledge and education. We cannot 
speak of iodine and iron uniting lump to lump, as two bricks are 
cemented together or blocks of wood glued together, for such is not 
the kind of action. IV e cannot select a minute fragment of each to 
regard as the combining portions, for the minutest fragment we cou’d 
obtain is visible, and iodide of iron contains neither visible iodine 
nor visible iron. And yet iodide of iron contains both iodine and 
n on, or, at least, a given weight of the compound is obtained from 
the same.weight of the constituents, and the same weight of con- 
stituents is obtainable from an equal weight of the compound. We 
might say that molecules are concerned in the operation, but mole- 
cules means, little masses of—of wrhat? there is positively no word 
left with which to carry on conversation and description but atoms. 
Any other mode of treating the matter is too subjective for general 
employment. Moreover, any difficulty in forming a definite concep- 
tion of an atom is met by regarding an atom, not necessarily as 
something which cannot be divided, but as “ a particle of matter 
which undergoes no further division in chemical metamorphoses” 
(fvekule).. Even physicists regard atoms from much the same point 
of view: indeed they often speak of still larger portions of matter 
(molecules) as atoms, meaning thereby “ something which is not di- 
vided in certain cases that we are considering” (Clifford). 
hat power binds the atoms of a chemical compound together in 
such marvellous closeness of union that in the couple or group they 
lose all individuality? Clearly an attractive force of enormous 
power, a force remotely resembling, perhaps, that which attracts a 
piece.or iron to a magnet. Only by such an assumption can we 
conceive that common salt contains chlorine and a metal (sodium), 
or that wood contains carbon, hydrogen, and oxygen. Were not 
The Chemical Force. 38 
GENERAL PRINCIPLES OF 
this force thus all-powerful, the carbon in wood would show its 
blackness and other qualities, and the hydrogen and oxygen give 
indications of their gaseous and other characters. This attractive 
force is commonly termed the chemical force, sometimes chemical 
affinity. The word chemism has also been proposed for it, just as 
the magnetic force is termed magnetism, but has not been gene- 
rally adopted. 
A free, uncombined atom probably cannot exist in a state of iso- 
lation, at common temperatures, for any appreciable length of time. 
For we must regard an atom as the home of an attractive force of 
great intensity, and the moment such an atom is liberated from a 
state of combination (say hydrogen from water, or chlorine from 
salt)—it finds itself in proximity to another atom having similar 
desires for union, so to speak; the result is an impetuous rushing 
together and formation of either couples, trios, or groups, according 
to the nature of the atoms. It would be as difficult to conceive of 
separate atoms as to imagine that a strong magnet and a piece of 
steel could be suspended close to each other without being drawn 
together. It is, doubtless, possible to keep some pairs of atoms 
apart by the aid of heat, just as the magnet and steel may be parted 
by a superior amount of force, but such a condition of things is 
probably abnormal. These pairs and other groups of atoms are 
conveniently designated by the one word molecule, the diminutive 
of mole, a mass; literally little masses. Dissimilar kinds of atoms 
seem to have greater attraction for each other than similar kinds; 
for, first, the masses of matter met with in nature in the great ma- 
jority of cases contain two or more dissimilar elements; and, sec- 
ondly, at the moment certain elements are liberated from their com- 
bination, they are very specially active in combining with other, 
different, elements; that is to say, the chances are not equal that 
the liberated elements will either retain their elementary condition 
or combine to form compounds, but the cases in which compounds 
are formed are actually in great majority. 
Molecules. 
It is desirable that the learner should here make some experi- 
ment which will serve to bring again under notice in an applied or 
concrete form what has just been stated respecting the substances 
termed chemical compounds, and concerning the character of that 
chemical force which resides in the atoms of molecules. The follow- 
ing will usefully serve this purpose; it is the process for detecting 
a trace of sulphurous acid in common liquid hydrochloric acid. 
Recapitulation. 
As already proved, hydrogen gas and chlorine gas, when 
united, form hydrochloric acid gas: the latter dissolved in 
water is the ordinary liquid of the shops termed Hydrochloric 
Acid, the Acidum Hydrochloricum or Murinticum of Pharma- 
copoeias. Commercial samples of this liquid not unfrequently 
contain as an impurity a trace of sulphurous acid gas, a body CHEMICAL PHILOSOPHY. 
39 
also already mentioned and experimentally prepared—a trace 
too small to be detected by its odor. Obtain a specimen of 
common liquid hydrochloric acid containing as an impurity a 
trace of sulphurous acid, or adopt the more simple course of 
purposely adding a few drops of aqueous solution of sulphur- 
ous acid (Act dum Sulphurosumf U. S. I"*.) to some hydro- 
chloric acid. (If no sulphurous acid is at hand, the object 
may be accomplished by pouring a quarter or half an ounce 
of liquid hydrochloric acid into a wide-mouthed bottle, then 
burning a fragment of sulphur on a wire or strip of wood in- 
side the bottle for a few seconds, and shaking the gas and liquid 
together.) Pour some of the impure liquid hydrochloric acid 
into a test-tube, add about an equal bulk of water, and then 
diop in some fragments of the metal zinc. Effervescence will 
occur, due to the escape of inodorous hydrogen gas, together 
with a small quantity of a badly-smelling gas, termed sulphur- 
etted hydrogen gas. Bring the mouth of the tube under the 
nose; the presence of sulphuretted hydrogen will at once be 
recognized. 
The hydrochloric acid has now been tested for sulphurous acid. 
If the experiment be performed on any commercial specimen of the 
acid, and a smell of sulphuretted hydrogen be observed, the ope- 
rator will at once be able to state that the specimen contains sul- 
phurous acid as an impurity. 
Using Dalton’s theory of the atomic constitution of matter, the 
explanation of what occurs in the successive steps of the foregoing 
experiment is as follows:— 
Hydrochloric acid is a chemical compound of hydrogen and chlo- 
rine. That it is a chemical compound, and not a mere mechanical 
mixture of hydrogen and chlorine, is shown by the fact that its 
properties are altogether different from the properties of its con- 
stituents. 1 he attractive power or chemical force resident in the 
atoms of chlorine and of hydrogen has caused them to combine in 
the closest manner imaginable and form pairs of atoms or molecules 
of the chemical compound—hydrochloric acid. Zinc being intro- 
duced into the acid, and the atoms of zinc and chlorine having even 
still greater attraction for each other than the hydrogen for the 
chlorine, the zinc and chlorine atoms combine and form a new 
molecule (termed chloride of zinc) which remains in the liquid, 
while the hydrogen atoms, having the atoms of no other element 
to combine with if the acid is pure, unite to form pairs, or mole- 
cules of hydrogen, and in that state escape from the vessel. If the 
acid be impure from the presence of sulphurous acid (sulphurous 
acid gas, it will be remembered, is a compound of sulphur and 
oxygen), some of the hydrogen atoms, at the moment of their birth, 
. * These aqueous solutions of acids are generally, for the sake of brev 
lty, simply termed acids. 40 
GENERAL PRINCIPLES OF 
their nascent state (from nascor, to be born)—the specially active 
state—finding the atoms of other elements present, namely, the 
atoms of sulphur and oxygen of the sulphurous acid molecules, 
combine by preference with these atoms and form new molecules, 
the sulphur and hydrogen forming sulphuretted hydrogen, and the 
oxygen and hydrogen producing water: the former escapes with 
the great bulk of the hydrogen, while the water remains with the 
water already in the vessels. 
Note.—Ordinary hydrogen gas, that is, hydrogen not in the nas- 
cent condition, will not thus attack sulphurous acid. Doubtless the 
amount, or extent, of attraction of two atoms of hydrogen for one 
atom of, say, the sulphur in the sulphurous acid molecule is a con- 
stant amount, but the uncombined nascent atoms can, it is only fair 
to suppose, get much nearer to the attacked molecule than they can 
after they have themselves combined to form a molecule, molecules 
(but not atoms) having an appreciable amount of space between 
them, as will be further shown almost immediately. In other 
words, it is probably distance which prevents an attack which 
would be inevitable at close quarters. These remarks apply to all 
similar reactions of other elements. 
Conditions and Nature of the Manifestation of tiie Chem- 
ical Force. 
The exertion of chemical affinity is only possible when the masses 
of the bodies touch. Thus it was necessary to bring the oxygen, 
hydrogen, phosphorus, chlorine, sulphur, carbon, iodine, and iron 
into ordinary contact, in the respective experiments with those ele- 
ments, before the various reactions occurred. The exact nature of 
these actions, as indeed of all in which substances act chemically, 
would seem to be an interchange, most generally a mutual one, of 
the atoms of which the molecules consist—a change of partners, so 
to speak. Thus, in the experiment in which hydrogen and chlorine 
gases united to form hydrochloric acid gas, a pair of atoms in a hy- 
drogen molecule, and a pair of atoms in a chlorine molecule, find- 
ing themselves opposite to each other, change places, the atoms of 
each of the old molecules unlinking, so to say, and pairing off in 
fresh couples—as two brothers who for many years have been close 
companions, and two sisters similarly united, thrown freshly into 
each other's society, soon accept new and still more congenial cou- 
p lenient. 
f Hydrogen 
[ Hydrogen 
and 
Chlorine' 
Chlorine 
become 
Hydrogen 
Chlorine 
and 
Hydrogen 
Chlorine 
Or, using the symbols of these elements instead of the full names, 
Still further economizing space and trouble, the same statement 
may be made in the following form:— 
II II and Cl Cl become II Cl and II Cl. 
II2 and Cl2 become 2IIC1. 
Once more, by using the plus (+) instead of the words “ and ” or CHEMICAL PHILOSOPHY. 
41 
11 added to," and the sign or symbol = or equal instead of the words 
‘‘become" or “are equal to,” we reach the shortest method of ex- 
pressing this chemical action :— 
II2 + Cl2 = 2HC1. 
This is the form in which such an action may be expressed in the 
student's note-book. It is the shortest and most convenient form, 
and is instructive and suggestive to the mind. 
We have thus gradually arrived at a spot in the path of chemical 
philosophy at which we must halt to more fully discuss the usual 
method of recording chemical travels. A\re have arrived at the sub- 
ject of chemical notation (from noto, I mark), the art or practice of 
recording chemical facts by short marks, letters, numbers, or other 
signs. Already the first capital letter, or the first and one of the 
following small letters of the Latin names of the elements have been 
employed as contractions, or short-hand expressions, or symbols of 
the whole name. Thus 11 has been used for the word “ hydrogen,” 
and Cl for “chlorine.” A second function of such a symbol is that 
of indicating one atom. Thus II stands not only for the word or 
substance “ hydrogen,” but for one atom of hydrogen. Large and 
small figures (2 or 2) indicate a corresponding number of atoms, the 
small figure only multiplying the one particular symbol to which it 
is attached, while a larger figure multiplies all the symbols it pre- 
cedes. Thus II2 means two atoms of hydrogen, and Cl2 two atoms 
of chlorine •, while 2HC1 means two atoms of hydrogen and two 
atoms of chlorine, or, in one word, two molecules of hydrochloric 
acid gas. A third function of such a symbol as II or Cl is that of 
indicating one volume of the element in the gaseous state. Thus II, 
Cl, and O stand, first, for the substances named hydrogen, chlorine, 
and oxygen ; secondly, for single atoms of hydrogen, chlorine, and 
oxygen. Thirdly, they represent single and equal volumes of chlo- 
rine, hydrogen, and oxygen. It will be remembered that one testr 
tubeful of hydrogen and an equal sized test-tubeful of chlorine were 
employed in a previous experiment in forming hydrochloric acid 
gas, IIC1. 
The position of symbols counts for something. Thus HC1 indi- 
cates not only the substances hydrogen and chlorine, single atoms 
of each of the substances, and equal volumes of each, but also that 
the two substances are joined together by the chemical force. If the 
two letters were placed one under the other, or at some distance 
apart, or were separated by a comma or a plus sign (+), they would 
be understood to mean a mere mixture of the elements; but placed 
as close as the printer’s types will conveniently and consistently 
allow, they must be considered to stand for a compound of the ele- 
ments, that is to say, hydrochloric acid gas (IIC1). The collection 
of symbols representing a molecule is termed a formula. II2, Cl2, 
and IIC1 are the formulae of hydrogen, chlorine, and hydrochloric 
acid gas. 
Chemical Notation. 
11,-1- Cl, — 2IIC1. 42 
GENERAL PRINCIPLES OF 
Such a set of letters, figures, and marks as that on the preceding line 
is collectively termed an equation, because it indicates the equality 
of the number and nature of the atoms before and after chemical 
action. On the left hand of the sign of equality are shown two 
molecules, and on the right hand two molecules; but, of the mole- 
cules on the left, one contains two atoms of hydrogen and the other 
two atoms of chlorine, while of the molecules on the right each con- 
tains one atom of hydrogen and one of chlorine. The equation forms 
a short and convenient plan of recording the facts of experiment. 
Instead of an equation, a diagram may be employed to exhibit 
the same fact. Thus :— 
1I2 
II 
II 
1IC1 
Cl2 
Cl 
Cl 
IIC1 
PHYSICAL AND CHEMICAL CONSTITUTION OF 
MATTER. 
Relations of Gases, Liquids, and Solids. 
Molecules of gases are not in absolute contact, for a volume of 
gas may be compressed with very little force to half or one-fourth 
its bulk—in short, to such an extent that in many cases the mole- 
cules sufficiently approximate to form a liquid. In a liquid the 
molecules are still free to glide about with ease amongst each other; 
and though in solids they exhibit less mobility, still even solids may 
be compressed by powerful pressure, so that probably in no instance 
are molecules in absolute contact. (Moreover, from the researches 
of Caignard de la Tour, and, recently, of Andrews, there would 
seem to be no sharp lines of demarcation between the gaseous, 
liquid, and solid conditions of substances.) One’s mental picture 
of the relative position of the molecules of gaseous, vaporous, 
liquid, or solid matter must be such a picture as that of the mov- 
ing particles of dust in the air of a room, or such a relation to each 
other as that of the planets and stars suspended in space. There is 
abundant experimental evidence to warrant such a conception. A 
clear transparent fluid appears peiTectly homogeneous, but is not so. 
Its particles are not in contact. Every one who has mixed 5 pints 
of rectified spirit with 3 pints of water knows that the 1(X) fluid- 
ounces of spirit and 60 fluidounces of water do not when mixed 
give 160 ounces of “proof” spirit, but only 156 ounces; the mole- 
cules of the liquids have gone closer together, having probably a 
little attraction for each other. Why a gas under pressure should 
immediately return to its original bulk when the pressure is re- 
moved, while a liquefied or solidified gas only slowly resumes the 
gaseous or vaporous state, is a question which requires for discus- 
sion a knowledge of the nature of forces other than the chemical. CHEMICAL, PHILOSOPHY. 
43 
For it must be remembered that the study of the chemical force is 
mainly the study of the internal constitution of molecules, the study 
of the properties of entire molecules forming the domain of Physics 
—sometimes termed Natural Philosophy. (Physics, from <pi>me, 
phusis, nature, that is, visible and material nature; the study of 
actions and reactions which do not involve entire and permanent 
change in the properties of bodies—the study of the action of heat, 
light, electricity, magnetism, gravitation, etc., on matter.) 
It is necessary, however, to state something more about the 
physical as well as the chemical conditions of the molecules of a 
gas in order that the learner may be prepared for the fact, that mix- 
tures of certain gaseous elements, in combining to form gaseous 
compounds, diminish considerably in volume. Thus, while a pint 
of hydrogen and a pint of chlorine give a quart of hydrochloric 
acid gas, 
Hydrogen. J 
Chlorine. 
Hydrochloric acid gas. 
two pints of hydrogen and one of oxygen are necessary to produce 
a quart of gaseous water (steam). It will be remembered that two 
volumes of hydrogen and one of oxygen were necessary in a pre- 
vious experiment in which water was formed. 
Hydrogen. | 
Hydrogen. 
Oxygen. 
Gaseous water (steam). 
Now, that a pint of hydrogen gas and a pint of chlorine gas should, 
after chemical reaction or rearrangement of the atoms of the mole- 
cules has taken place, form two pints of hydrochloric acid gas, is 
quite what we should expect. For, first, the reader, by this time, 
is not astonished that the chemical combination is attended by entire 
change of properties; and, secondly, the experience of years has 
led him to expect that a pint of one thing added to a pint of another 
gives two pints of the mixture. But that two pints of hydrogen and 
one pint of oxygen should, after combination (and under like con- 
ditions of temperature and pressure), give, not three, but two pints 
of product (steam) is perhaps somewhat astonishing, and needs 
explanation. To this end let us picture a few of the molecules 
of hydrogen and as many molecules of chlorine. Draw with a 
pencil on paper several pairs of -(—j- ) to represent hydro- 
gen molecules and circles (O O) for chlorine molecules, or, if colored 
ink is at hand, red pairs of dots for hydrogen and green for chlo- 44 
GENERAL PRINCIPLES OF 
rine. Or, at once, for facility in printing, let the following pairs of 
letters h h represent a few (say, nine) molecules of hydrogen, and 
c c molecules (nine) of chlorine—before combination. 
h h h h bh 
h h h b h h 
bh bb h h 
c c c c e c 
c c e c c c 
c c c c c c 
Then, after combination, we shall have eighteen molecules of 
hydrochloric acid gas :— 
he he he 
he be he 
he he be 
he he he 
he he he 
he he he 
But when two volumes of hydrogen and one of oxygen combine 
and give two volumes of steam, the mental picture must be not that 
of molecules somewhat' nearer to each other than before, nor any 
difference in the size of the molecules, but a picture of molecules 
containing three instead of two atoms—thus, still using pairs of 
letters, just for the moment, to represent a few (the space will allow 
only twenty-seven) molecules :— 
h h h h h h 
h h h h h h 
h h h h h h 
h h h h h h 
h h h h h h 
h h h h h h 
o o oo oo 
oo oo oo 
0 0 0 0 0 0 
The twenty-seven molecules (eighteen hydrogen, nine oxygen) 
will, after combination, become eighteen molecules of steam: 
h o h h o h h o h 
h o h h o h h o h 
h o h h o h h o h 
h oh h o h h o h 
h o h h o h h o h 
h o h h o h h o h 
As already suggested, one’s mental picture of a number of mole- 
cules may well give them such a relation to each other as that of a 
number of solar systems in the universe, equally distant from each 
other and each occupying a similar space, yet one system containing 
a sun and one planet, another a sun and two planets, and so on, or 
even one or more of the planets having one or more moons. Indeed 
the atoms in some very complex molecules really appear to have 
very much the relation to each other of the sun, planets, and moons 
of a solar system. To indicate such molecules by letters as above 
would, of course, require more space than is there given to the 
assumed pictures of molecules. 
Here occurs an opportunity that must not be lost of stating a 
mode of reasoning by which a molecule of oxygen (or of many other 
elements) is shown to be a double structure—shown to contain two 
atoms. Five equal-sized hollies are before us, two filled with hydro- 
gen, one with oxygen, and two with steam. (The bottles are hot 
enough to prevent the steam condensing to water, and all five are at 45 
CHEMICAL PHILOSOPHY. 
the same temperature.) Apply heat so that all shall be equally 
heated, the three different substances expand equally. Cool equally, 
the contents contract equally. Apply equal pressure to all five, each 
is equally affected. Diminish pressure equally, each portion of the 
three substances equally expands. Gases (practically steam is a gas, 
it is simply not a permanent gas) thus similarly affected must be, 
physically, similarly constructed or constituted (a law which will 
again be referred to, on page 54); each bottle must contain the 
same number of particles or molecules, and at any one temperature 
and pressure the molecules in each must be equally distant from 
each other. We do not know what actual number or distance, but 
whatever the number and distance it is the same for each bottle. 
Say that one million is the number, then we shall have a million of 
molecules in the first hydrogen bottle, a million in the second, a 
million in the oxygen bottle, and a million in each of the steam 
bottles. We will cause chemical combination between the two mil- 
lions of hydrogen molecules and one million of oxygen molecules, 
producing (as we have seen) two millions of steam molecules, hav- 
ing the properties already stated. But a molecule of steam contains 
an atom of oxygen. Hence two millions of steam molecules con- 
tain two millions of oxygen atoms, which two millions of oxygen 
atoms have been obtained from one million of oxygen molecules. 
Therefore each molecule of oxygen was a double structure—each 
molecule of oxygen contained two atoms of oxygen. As Clifford 
says, “ you cannot put 50 horses into 100 stables, so that there shall 
be exactly the same amount of horse in each stable; but you can 
divide 50 pairs of horses among 100 stables.” 
Thus much respecting the constitution of gaseous or vaporous 
matter. Our knowledge of the constitution of liquid and solid mat- 
ter is still more limited. 
With regard to the notation of the subject, it will be sufficient to 
state here that while a symbol usefully represents one volume of any 
gas, a formula of any gas or vapor represents two volumes. By re- 
membering this general rule we may, by looking at a formula, tell 
how many volumes of constituents were concerned in the formation 
of a compound, and therefore what amount of condensation, if any, 
occurred during the act of formation. By thus reading and inter- 
preting the formula for water, II20, we see that two volumes of 
steam (at any temperature) may be obtained from two volumes of 
hydrogen and one volume of oxygen (at the same temperature), and 
thus that the extent of condensation when hydrogen and oxygen 
(at a stated temperature) unite to form gaseous water (at the same 
temperature) is from three to two. This subject will again be 
treated of in connection with those of Chemical Combination and 
the Specific Gravity of Gases. » 
Further Remarks on General Chemical Notation. 
We may now take an experiment already made as an additional 
example of chemical action, and describe the simplest way of express- 
ing the same by notation. When two volumes of hydrogen and one 
of oxygen were caused to combine, the production of flame and noise 46 
GENERAL PRINCIPLES OF 
proved that chemical action of some kind had taken place; had the 
experiment been performed in dry vessels, evidence of the precise 
action would have been found in the bedewment or moisture produced 
by the condensation of the water on the sides of the tube. Similar 
evidence was afforded on holding a cool glass surface over the hydro- 
gen-flame. The action is expressed in the following equation:— 
Instead of an equation, the following diagram may be employed:— 
2H1 + 0, = 2HJ0. 
211 
H2 
H,0 
0 
0 
The foregoing aggregation of symbols or short-hand characters, or 
formula, II20, is, then, a convenient picture of the facts that have 
already come before us, viz., that water is formed of the elements 
hydrogen, II, and oxygen, O; moreover, that it is formed of two 
measures or volumes of hydrogen, II2, to one of oxygen, O; and, 
thirdly, that the molecule of water (II20) is formed of two atoms of 
hydrogen (II2) and one of oxygen (0). The formula also fulfils the 
fourth function of indicating that the two volumes of hydrogen and 
one of oxygen in combining condensed to two volumes of steam. 
That the resulting bulk of steam afterwards shrunk most consider- 
ably in condensing to water is another matter altogether, a physical 
and not a chemical result, and due to the approximation of the mole- 
cules of water after formation. 
Another experiment already performed, illustrating the character 
of the manifestations of chemical force (symbolically noted as fol- 
lows), was that in which the red-hot carbon of wood was plunged 
into oxygen. The evidence of chemical action in that case was the 
sudden inflammation of the carbonaceous extremity of the wood. 
The particles of carbon and oxygen, having intense attraction or 
affinity for each other at that temperature, rush together so impetu- 
ously as suddenly to produce a large additional quantity of heat, 
an amount sufficient to cause the particles to emit an intense white 
light. The action between carbon and oxygen is expressed on paper 
in either of the following ways:— 
02 
n2o 
c2 
c 
c 
co2 
20, 
o2' 
<V 
C02 is the formula of the well-known gaseous body commonly 
termed carbonic acid gas. 
co2 CHEMICAL PHIL<JSOPIIY. 
47 
The reader should here draw for himself equations or dia- 
grams similar to those on page 46, and thus show the formation 
ot the three bodies he has already produced—namely, phosphoric 
anhydride (P-A), sulphurous acid gas (SO,), and iodide of iron 
(b el2), submitting the same, if possible, to a tutor or other 
authority to assure himself of their correctness. 
Aote.—In the foregoing experiments several illustrations occur 
of the formation of compounds having the gaseous, liquid, and 
solid conditions, in one of which three forms all matter in the uni- 
verse apparently exists. 
Laws op Chemical Combination (ev Weight). 
Chemistry as a science is little more than a hundred years old, 
though very many of the facts and operations we now term chemical 
have been known as isolated items of knowledge for centuries. Thus, 
the ancient Egyptians made glass, vitriol, soap, and vinegar ; and the 
Cxreeks started the idea that matter wras composed of a few elements, 
imagining earth, air, fire, and water to be elements. But the great 
general principles w hich interlace and bind together separate facts, 
those which from their extensive application and importance are de- 
nominated laws, have all been brought to light since the year 1770. 
Between 1785 and 1800, Bryan Higgins, William Higgins, Wenzel 
Iuchter, and Proust made analyses and researches which led up to 
the following generalizations: When compounds unite to form defi- 
nite chemical substances, they always combine in the same proportions. 
1 he curious character of this fact could but be most striking, and 
indeed is so now, to the mind receiving it for the first time. Thus 
water (a compound) added to quicklime (a compound) gives slaked 
lime, a perfectly definite chemical substance. But whereas sand and 
water, sugar and water, sand and sugar, and such mixtures may be 
obtained by adding together the ingredients in any proportions what- 
ever, say 90 of sugar and 10 of sand, or 10 of sugar and 90 of sand, 
slaked lime (say 1(X) parts) invariably results from the combination 
of 7of ol quicklime and 24 j of w'ater. If a larger proportion than 
751 per cent, of quicklime be employed, the excess remains as quick- 
lime mixed with the slaked lime; and if more than 24f per cent, of 
water be used, an excess of wmter remains with the slaked lime and 
evaporates if the mixture be exposed to the air. Dalton discovered 
that when elements unite to form a definite substance, they, like 
compounds, always combine in the same proportions; and he wras 
tho first to set forth the law in a manner which was at once clear 
and comprehensive enough to include the former generalization. 
Thus:— 
Fwst Law relating to Chemical Combinations. 
A definite compound always contains the same elements in the 
same proportions. 
Take another example. Common salt always eontains 39£ per 48 
GENERAL PRINCIPLES OF 
cent, of the metal sodium to 60f of chlorine, and water always 89 of 
oxygen and 11 per cent, of hydrogen (more exactly 88.89 to 11.11). 
As with quicklime and water, so with the chlorine and sodium, and 
the constituents of many (not all) chemical compounds; in such 
cases if either be added to the other in any quantity beyond stated 
proportions, the excess plays no part whatever in the act of combi- 
nation. (In some cases, as will be seen directly, excess of either 
plays a very simple but very remarkable part.) In short, whether 
a compound be made directly from its elements, or by the combina- 
tion of other compounds, or indirectly as one of two products of the 
action of substances chemically on each other, whatever be its ori- 
gin, if it is a definite compound it always contains the same ele- 
ments in the same proportions. 
Dalton further made such experimental researches as enabled him 
to lay down a second great law. lie found that, while many sub- 
stances only united chemically in one proportion, others combined in 
two or even more, and he studied several such naturally related 
bodies. He found that while carbonic oxide (a gas formed when 
charcoal is burned with an insufficient supply of air) contains such 
a proportional weight of carbon and oxygen as is represented by (to 
use the simplest figures) 3 and 4, carbonic acid (a gas formed when 
charcoal is burned with excess of air) contains 3 of carbon to ex- 
actly twice 4 of oxygen. He proved that a similar relation existed 
between two compounds of carbon and hydrogen, and between a 
cluster of compounds of nitrogen and oxygen. The first of the 
latter, to a given quantity of nitrogen, contains a certain proportion 
of oxygen ; the next, to the same quantity of nitrogen, has exactly 
twice the proportion of oxygen : and the others have exactly three, 
four, and five times as much oxygen as the first, the quantity of 
nitrogen remaining the same throughout. Dalton thus generalized 
these facts:— 
Second Law relating to Chemical Combinations. 
When two elements unite in more than one proportion, the re- 
sulting compounds contain, to a constant proportion of one ele- 
ment, simple multiple proportions of the other—or the weights of 
the constituent elements bear some similar simple relations to each 
other. 
Thus carbonic oxide gas is a definite compound always containing 
fixed proportions of carbon and oxygen, and carbonic acid gas is 
also a definite compound always containing fixed proportions of 
carbon and oxygen. Both thus obey the first law of combination. 
But whereas carbonic oxide contains, or may be made from, 30 parts 
(ounces, grains, or other weights) of carbon and 40 of oxygen, car- 
bonic acid contains, or may be made from, 30 parts of carbon and 
exactly twice 40 of oxygen.* 
This second law cannot but be as striking as the first when fresh- 
ly unveiled to the mind. Sand and sugar, or any substances which 
do not act chemically on each other, may be mixed in the propor- CHEMICAL PHILOSOPHY. 
49 
tions of 30 to 40, 30 to 80, 30 to 60, or any other quantities; but if 
an attempt be made to burn 30 parts of carbon in 60 of oxygen, the 
elements will themselves naturally assert their own special com- 
bining powers, and refuse, so to say, to unite in these proportions: 
the 30 of carbon will first combine with 40 of oxygen and form 70 
of carbonic oxide, and this gas, which, had it the opportunity, would 
combine with 40 more of oxygen and form carbonic acid gas, find- 
ing only half that quantity, namely, 20, of oxygen present, contents 
itself by one-half (that is, 35 of carbonic oxide), accepting the 20 of 
oxygen and becoming carbonic acid gas, while the other half re- 
mains as carbonic oxide. This is a most wonderful fact. Again, 
if 30 parts of carbon be burnt in more than 80, say 85, of oxygen, 
only 80 will be used, the other 5 remaining as oxygen merely mixed 
with the resulting carbonic acid gas. If we attempt to burn 30 
parts of carbon in less than 40 of oxygen, the oxygen will take up 
three-fourths its weight of carbon and form carbonic oxide, while 
the excess of carbon will remain as carbon. 
Nature does not always permit man to mix things in any propor- 
tions he pleases. She does sometimes. She does if he only stirs 
things together, or if he only uses the attractions of adhesion or co- 
hesion in binding the materials together; but if he employs chem- 
ical attraction, she restricts him to special proportions. That is to 
say, if the things mixed do not attack one another or intimately 
combine, then admixture may he effected in any proportion; and 
the mixture is a mere mixture having the mean properties of its 
components. Examples of such mixtures are seen in compound 
plasters, pill-masses, confections, and plum-puddings. But if the 
things do unite to form, not a mere mixture having the mean prop- 
erties of its components, hut a compound having new and distinct 
and definite characters of its own, then nature does not permit man 
to mix the things in any proportion he pleases. The proportion is 
one fixed and constant; and if he substitutes proportions of his own, 
the things unite in the proportions fixed by nature, and the excess 
he has added either remains in its original uncombined condition, 
or it combines with the compound already produced to form a sec- 
ond different compound. Any one compound, that is, the same 
compound, always contains the same elements in the same propor- 
tions, and can only be made from the same elements in the same 
proportions. An attempt to mix the same elements in other pro- 
portions would result in one of two failures, namely, either the 
extra proportion would remain free and uncombined, or it would 
combine and convert the first compound, or a portion of it, into a 
different compound. The fresh compound thus produced, like the 
first, and indeed like all definite compounds, of course always con- 
tains the same elements in the same proportions. 
In short (law 1) any definite compound always contains the same 
elements in the same proportions, and (law 2) any two elements 
uniting in more than one proportion unite in multiples of that pro- 
portion, and produce so many different definite compounds. Tak- 
Recapitulation. 50 
GENERAL PRINCIPLES OF 
ing hydrogen as uniting in proportions of 1, oxygen unites in pro- 
portions of 16—that is, 16, twice 16, thrice 16, and so on, never in 
intermediate proportions. Carbon unites in proportions of 12, sul- 
phur of 32, chlorine of 35J. And every other element has its com- 
bining proportion fixed by nature. 
The student of chemistry is recommended to accept these two 
great natural facts, great enough to be dignified by the name of 
laws, in all their inherent solidity and simplicity. Of course, he 
will wonder why substances should combine, chemically, only in 
fixed proportions when forming a definite body, and why, when a 
substance combines in more than one proportion to form different 
compound bodies, the proportions should only be multiple propor- 
tions ; and an extremely ingenious and useful explanation has been 
suggested by Dalton (see the following paragraphs on the theory 
that matter is built up of atoms); but man has not yet succeeded 
in so questioning nature as to gain from her a satisfactory answer 
to such questions; hence, until he does succeed, any hypothesis, 
such as Dalton’s, should be held intelligently hut loosely. The 
facts themselves, however, should be grasped with the student’s 
utmost tenacity. 
Third Law relating to Chemical Combination. 
Careful consideration of the foregoing two great laws has 
suggested an important truth sometimes termed The Law of 
Chemical Combination, namely: The proportions in which two 
elements unite with a third are the proportions (or simple mul- 
tiples or submultiples of the proportions) in which they unite with 
each other. Thus oxygen in proportions of 16 unites with 
hydrogen, and carbon in proportions of 12 unites with hydro- 
gen ; therefore 16 and 12 are the proportions in which oxygen 
and carbon will unite with each other* 
The Atomic Theory. 
The laws which Dalton (1803 to 1808) so largely aided to unveil 
—two grand and wonderful truths—he explained and correlated by 
a siirTple and beautiful hypothesis. Dalton suggested that matter 
was not infinitely divisible, but composed of minute particles or 
atoms having an invariable character. In the words of Wurtz, 11 To 
an old and vague notion he attached an exact meaning by supposing 
that the atoms of each kind of matter possess a constant weighty and 
that combination between tico kinds of matter takes place not by pene- 
tration of their substance, but by juxtaposition of their atoms.'" 
Thus under this hypothesis, or atomic theory as it is generally 
termed, carbonic oxide is a definite compound always containing 
* See Axiom 1 in Hawtrey’s fascinating “ Introduction to the Ele- 
ments of Euclid,” Longmans & Co., London, 2s. 6d., a book strongly 
recommended to any chemical student who is not familiar with the 
mode of reasoning commonly termed geometrical. CHEMICAL PHILOSOPHY. 
51 
the same elements in the same proportions, because each particle of 
it is composed of an atom of carbon and an atom of oxygen chemi- 
cally united, the weights of the atoms being in the proportion of 3 
and 4, that is, having a constant weight of 12 and 16, as we now 
believe. Carbonic acid gas is also a definite compound always con- 
taining the same elements in the same proportions, and the propor- 
tion of oxygen is just double that in carbonic oxide, because each 
particle of it is composed of an atom of carbon (weighing 12) and 
two atoms of oxygen (each weighing 16). 
C 
12 
O 
16 
O 
16 
C 
12 
o 
16 
Again, the facts that writh 12 of carbon oxygen unites in the pro- 
portion of 16, or a multiple of 16 ; that with" 12 of carbon sulphur 
unites in the proportion of 32, or a multiple of 32 (the liquid known 
as disulphide of carbon is a chemical compound of 12 of carbon to 
twice 32 of sulphur) ; and, thirdly, that oxygen and sulphur unite 
in proportions of 16 and 32, are at once explained on the assump- 
tion that these elements exist in atoms which have the respective 
weights mentioned. Existing in indivisible particles (atoms) which 
weigh 16, 12, and 32, oxygen, carbon, and sulphur must unite in 
indivisible weights of 16, 12, and 32. 
Imaginary pictures of molecules of carbonic oxide gas and carbonic acid gas.* 
What has just been stated respecting two or three elements is 
true of all the elements. It is a fact, that, when elements unite 
with one another in the peculiar and intimate manner termed chem- 
ical, they do not combine in the haphazard proportions of a mere 
mixture, but in one fixed and constant proportion. Such propor- 
tions or weights represent, according to Dalton, the weights of their 
atoms. Oxygen unites with other elements in proportions of 16, 
therefore 16 is the weight of the atom of oxygen. Chlorine unites 
with other elements in proportions of 35£, therefore 35J is the 
atomic weight of chlorine. And for a similar reason the atomic 
weights of hydrogen will be 1, carbon 12, sulphur 32, nitrogen 14, 
and iodine 127. Of course it will be understood that these are the 
relative weights of atoms, for we cannot know the absolute weights. 
All that is known is that the chlorine atom, for instance, is 35.5 
times as heavy as the hydrogen atom, wdiatever the absolute weight 
Atomic Weights. 
* The size of atoms, their shape, their absolute weight—whether or 
not they are in actual contact—whether or not they are fixed in rela- 
tion to each other, free to move about each other, or in a constant state 
of motion—and whether or not the chemical force actuates them as the 
force of gravitation influences our earth, and moon, and solar systems, 
are matters of which at present we know almost nothing. The two 
pictures are not intended to convey any impression that the following 
formulae do not give: CO or OC, OCO or OOC or COO or CO,. 52 
GENERAL PRINCIPLES OF 
of the latter may be, and the iodine atom 127 times as heavy. The 
quantity of metal which with 35.5 of chlorine will form a chloride, 
and with twice 35.5 a second chloride (dichloride or bichloride), will 
require 127 of iodine to form an iodide, and twice 127 of iodine to 
form a second iodide (a diniodide or biniodide).* 
Note on Notation.—A fourth function of a symbol is to represent 
atomic iveight. Thus the symbols II, Cl, O, etc., not only perform 
the office of representing (a) names, (b) single volumes, and (c) sin- 
gle atoms, but (d) definite weights of the respective elements. 
II = 1, Cl = 35.5, 0 = 16, I = 127, N = 14, K = 39, etc. 
Laws of Chemical Combination (by Volume). 
In 1809 Gay-Lussac showed it to be a fact that when gaseous ele- 
ments unite with one another in the intimate manner termed chem- 
ical, they do not combine in the haphazard proportions (that is, pro- 
portions by measure or volume) of a mere mixture, but*in constant 
proportions in the case of any single definite compound, and in sim- 
ple multiple proportions in cases where two elements form more 
than one definite compound, lie thus proved that the laws respect- 
ing the constancy of weight with which elements combine hold good 
with reference to volume, at all events in those cases in •which ele- 
ments exist in or can be made to assume the gaseous condition. A 
volume of hydrogen gas and an equal one of chlorine gas give hy- 
drochloric acid gas. Two volumes of hydrogen and one of oxygen 
give water-vapor or steam. Such volumes or simple multiples are 
alone the proportions by bulk in which elements combine. If any 
excess of either gas be mixed and combination attempted, only the 
stated proportions really combine, the excess remaining unaltered. 
Further, following Gay-Lussac, on weighing these similar and equal 
volumes of hydrogen, chlorine, and oxygen, we find that the chlo- 
rine is 35.5 times as heavy as hydrogen, and oxygen 16 times as 
heavy as hydrogen. 
In 1811 and 1814, Avogadro and Ampere, reasoning on the fact 
that all gases are similarly affected by variations of pressure (Boyle, 
1662, verified by Mariotte) and temperature (Charles), concluded 
that all gases must be similarly constituted—similarity in proper- 
ties always indicating similarity in character or nature; in other 
words, that, if equal volumes of gases be taken under like conditions, 
each will contain the same number of molecules, similar in size and 
equally distant apart. The deduction is obvious. The weights of 
molecules of gaseous elements (that is, pairs of atoms, and therefore 
of atoms themselves) must differ to the extent that the weights of equal 
volumes of those elements differ. Equal volumes of hydrogen, chlo- 
rine, and oxygen, weighing respectively 1, 35.5, and 16, and each 
of these volumes containing an equal number of molecules, each 
* Only the atomic weights of the above and a few of the chief metal- 
lic elements need be committed to memory; others can he sought out 
as occasion may require. A complete Table of combining proportions 
of elements, or Atomic Weights, is given at the end of the volume. CHEMICAL PHILOSOPHY. 
53 
formed of two atoms, it follows that the relative weights of the 
atoms will be 1, 35.5, and 16. 
It will thus be seen that the weight of the volume in which an 
element combines, and the actual weight in which it combines, irre- 
spective of volume, are identical. For instance, we should find by 
experiment that, as a simple matter of fact, oxygen unites with other 
elements in proportions of 16 by weight, while hydrogen combines 
in proportions of 1. Turning, then, to experiments on the volumes 
in which hydrogen or oxygen combine, and having ascertained those 
volumes, and then having weighed them, wre should find that the 
oxygen volume weighs 16, w'hile the hydrogen weighs 1. In com- 
pounds in which hydrogen wras found in proportions of 1 grain, oxy- 
gen would be found in proportions of 16 grains. In gaseous com- 
pounds in which hydrogen wras found in proportions of, say, 27 
ounces by measure, oxygen wrould be found in proportions of 27 
ounces by measure; the 27 ounces of hydrogen would be found to 
wreigh 1 grain, and the 27 ounces of oxygen to weigh 16 grains. 
Thus the two great facts or laws respecting chemical compounds 
which Dalton laid down by ascertaining the exact weights in which 
bodies combine, Gay-Lussac confirmed by experiments on the exact 
volumes in which elements combine. Further, Gay-Lussac’s exper- 
iments and Avogadro’s reasoning strongly supported Dalton’s theory 
of atoms. 
Recapitulation. 
What are atomic weights or combining weights? First, they are 
represented by the smallest proportion (relative to 1 part of hydro- 
gen) in which an element migrates from compound to compound. 
Thus 1 part by weight of hydrogen can be eliminated from 18 sim- 
ilar parts of water by action of certain metals, leaving 1 of hydrogen 
and 16 of oxygen combined with the metal. From the latter com- 
pound 1 more of hydrogen is eliminated by a second experiment with 
more metal, leaving 16 of oxygen combined with the metal. In these 
and other well-known reactions 16 parts of oxygen take part in the 
various operations; 16, therefore, is the probable atomic weight of 
oxygen; and so with other elements and radicals. Secondly, the 
weights of the atoms, or the atomic weights, of the gaseous elements 
already studied, must differ from each other to the extent that equal 
volumes of those elements differ in weight. For equal volumes of’an 
element contain an equal number of molecules equal in size (Avoga- 
dro’s and Ampere’s conclusion), and each molecule is composed of two 
atoms ; so that equal volumes of elements contain an equal number 
of atoms. Now, bulk for bulk, chlorine is thirty-five and a half 
(35.5) times as heavy as hydrogen; so that the molecule of chlorine 
must be 35.5 times the weight of the molecule of hydrogen ; for 
molecules are equal in bulk. And as the molecules of chlorine and 
hydrogen contain two atoms each, the atom of chlorine must be 35.5 
times as heavy as that of hydrogen. The actual weight of atoms 
can never be ascertained, but that is of little consequence if we can 
only determine, with exactitude, their comparative weights. Com- 
paring, then, all atomic weights, sometimes obscurely termed equiv- 
alents, with each other, and selecting hydrogen as the standard of 54 
GENERAL PRINCIPLES OF 
comparison (because it is the lightest body known, and therefore, 
probably, will have the smallest atomic weight), and assigning to it 
the number 1, we see that the atomic weight of chlorine will be 
represented by the number 35.5. By parity of reasoning the atomic 
weight of oxygen is 16 ; for oxygen is found, by experiment, to be 
16 times as heavy as hydrogen. Similarly the atomic weight of 
nitrogen is found to be 14. The atomic weight of carbon is 12—not 
because its vapor has been proved to be 12 times as heavy as hydro- 
gen, for it has never yet been converted into the gaseous state, but 
because no gaseous compound of carbon, which has been analyzed, 
has been found to contain in 2 volumes (one of which, if hydrogen, 
would weigh 1 part) less than 12 parts of carbon. 
By thus weighing equal volumes of gaseous elements, or equal 
volumes of gaseous compounds of non-volatile elements, and ascer- 
taining by analysis the proportion of the non-volatile element whose 
atomic weight is being sought to the volatile element whose atomic 
weight is known, the atomic weights of a large number of the ele- 
ments have been determined. Some of the elements, however, do 
not form volatile compounds of any kind ; the stated atomic weights 
of these elements, therefore, are at present simply the proportions by 
weight in which they combine with or displace elements whose atomic 
weights have been determined, the proportion being in most cases 
checked by isomorphic considerations and the relation of the element 
to other forces, especially heat.* ( Vide infra.) 
Molecular Weight and Molecular Volume. 
The weight of the molecule is simply the sum of the weights of its 
atoms; thus 
II2 = 2; 02 = 32; Cl2 = 71; II20 = 18; 1IC1 = 36.5. 
Molecular Volume.—If the quantities just mentioned be weighed 
out (in grains or other weights), or if the molecular weight of any 
gases or liquids be taken and exposed to similar (high) temperatures 
and pressures, they will all be found to occupy the same volume. 
Conversely, if equal volumes of gases or vapors be measured out, 
and then the whole weighed, the resulting figures (all referred to 2 
of hydrogen as a starting-point or standard) are the molecular 
weights of the respective substances. Thus a volume of hydrogen 
(about half a gallon) which, at a temperature of, say, 300° F. or 
400° F., and common atmospheric pressure, would weigh 2 grains, 
* homorphous bodies (from laoc, isos, equal, and poptyy, morphe, form) 
are those which are similar in the shape of their crystals. The iden- 
tity in crystalline form is so commonly associated with similarity of 
constitution that non-crystalline substances resembling each other in 
structure are often regarded as isomorphous. When one element 
unites with another in more than one proportion, and its atomic 
weight is so far uncertain, the isomorphism of either of its com- 
pounds with some other compound of known constitution is usually 
accepted as decisive evidence as to which proportion is atomic. The 
specific heat of elements will be treated of subsequently. CHEMICAL PHILOSOPHY. 
would in the case of vapor of water (steam) weigh 18 grains. 
Hence we are justified in considering, indeed compelled to con- 
sider, the molecule of water to contain two atoms of hydrogen 
(=2) and one of oxygen ( 16), and its formula to be 1I20 (=18), 
and not H402, in which case its vapor would be twice a s heavy as it 
really is found to be. 
Construction of Formulae.—The composition of hydrochloric acid 
(HC1), water (H20), ammonia (NH3), carbonic acid gas (C02), or 
any other compound, as well as the weight of an element that may 
be concerned in its formation, cannot be ascertained by actual ex- 
periment until the student is far advanced in practical chemistry—■ 
until he is able to analyze not only qualitatively, but, by help of a 
balance, quantitatively. The percentage composition of a substance 
having been determined by quantitative analysis, its formula is con- 
structed by aid of the foregoing and other theoretical considerations. 
The correctness of such formulae can be verified by expert analysts, 
but must be taken for granted by learners. This subject will again 
be referred to in the latter part of this Manual. 
Turning from the weights of atoms, their value may now be con- 
sidered ; their quantivalence (from quantitas, quantity, and valens, 
being worth) may be stated. The chemical value of atoms in rela- 
tion to each other may be compared to the exchangeable value of 
coins. As compared with a penny (Id.) a groat (4d.) is four-valued ; 
as compared with hydrogen carbon is quadrivalent. Here again 
hydrogen is conveniently adopted as the standard of comparison. 
An atom of oxygen in its relations to an atom of hydrogen is biva- 
lent (pronounced thus, biv/-a-lent; of double worth, from bis, twice, 
and valens); an atom of it will displace two atoms of hydrogen, or 
combine with the same number; nitrogen is usually trivalent 
(trivr/-a-lent; from ires, three, and valens); and carbon, quad-riv'-a- 
lent (from quatuor, four, or quater, four times, and valens). Chlo- 
rine, iodine, and bromine, as well as potassium, sodium, and silver 
among the metals, are, like hydrogen, univalent (u-niv'-a-lent; from 
anus, one, and valens). Barium, strontium, calcium, magnesium, 
zinc, cadmium, mercury, and copper, like oxygen, are bivalent. 
Phosphorus, arsenicum, antimony, and bismuth, like nitrogen, 
usually exhibit trivalent properties ; but the composition of certain 
compounds of these five elements shows that the several atoms are 
sometimes quinquivalent (quin-quiv'-a-lent; quinquies, five times, 
and valens). Gold and boron are trivalent. Silicon (the character- 
istic element of flint and sand), tin, aluminium, platinum, and lead 
resemble carbon in being quadrivalent. Sulphur, chromium, man- 
ganese, iron, cobalt, and nickel are sexivalent (sex-iv'-a-lent; from 
sex, six, or sexies, six times, and valens), but frequently exert only 
bivalent, trivalent, or quadrivalent activity. This quantivalence 
(quant-iv'-a-lence; from quantitas, quantity, and valens), also 
termed atomicity (maximum quantivalence), dynamicity, and 
equivalence of elements, may be ascertained at any time on refer- 
ring to the table of the Elements at the end of this volume, where 
Quantivalence of Atoms. 56 
GENERAL PRINCIPLES OF 
Roman numerals, i, n, hi, iv, v, vi, are attached to the symbols of 
each element to indicate atomic univalence, bivalence, trivalence, 
quadrivalence, quinquivalence, or sexivalence. Dashes (IF, CF', 
N7//) similar to those used in accentuating words are often used 
instead of figures in expressing quantivalence. The quantivalence 
of elements, as they one after another come under notice, should be 
carefully committed to memory ; for the composition of compounds 
can often be thereby predicated with accuracy and remembered with 
ease. For instance, the hydrogen compounds of chlorine, CF, oxy- 
gen, 0//, nitrogen, Ny//, and carbon, C////, will be respectively 
H'CF, H',0", IF.N"', and H'/F'",—one univalent atom, IF, 
balancing or saturating one univalent atom, CF ; two univalent 
atoms, IF2, and one bivalent atom, 0", saturating each other ; three 
univalent atoms, IF3, and one atom having trivalent activity, N'", 
saturating each other ; and four univalent atoms, IF4, and one quad- 
rivalent atom, C"", saturating each other. Carbonic acid gas, 
ClvOn2, again, is a saturated molecule containing one quadrivalent 
and two bivalent atoms. 
The subject of quantivalence will be further explained after the 
frst six metals have been studied, when abundant illustrations of 
it will have occurred. 
DEFINITIONS. 
Chemistry is the study of the chemical force. 
The Chemical Force, like other forces, cannot be described, for, 
like them, it is only known by its effects. It is distinguished from 
other forces by the facts that (a) it produces an entire change of 
properties in the bodies on which it is exerted, and (b) that it is 
exerted only between definite weights and volumes of matter. Like 
the force of cohesion, which is the name given to the attraction 
which molecules have for each other, and which is great in solids, 
small in liquids, and apparently absent in gases, and like the force 
of adhesion, which is the name given to the attraction which a mass 
of molecules has for another mass, the chemical force acts only 
within immeasurable distances: indeed, inasmuch as the chemical 
force appears to reside in atoms, that is to say, is exerted inside a 
molecule, while all other forces affect entire molecules, the chemical 
force may be said to be distinguished (c) by being exerted within a 
smaller distance than that at which any other force is exerted. 
An Element is a substance which cannot by any known means be 
resolved into any simpler form of matter. 
An Atom of any element is a particle so small that it undergoes 
no further subdivision in chemical transformations. 
A Molecule is the smallest particle of matter that can exist in a 
free state. 
A mere Mixture of substances is one in which each ingredient re- 
tains its properties. 
A Chemical Compound is one in which definite weights of con- CHEMICAL PHILOSOPHY. 
stituents have combined, and during combination, have undergone 
an entire change of properties. A “compound” in pharmacy is an 
intimate mixture of substances, but still only a mixture; it is not a 
chemical compound, the ingredients have not entered into chemical 
union or combination. 
Combustion is a variety of chemical combination, a variety in 
which the chemical union is sufficiently intense to produce heat 
and, generally, light. 
The Law of Diffusion is one under which gases mix with each 
other at a rate which is in inverse proportion to the square root of 
th ir relative weights ; that is, irrespective of and even in spite of 
their comparative lightness or heaviness. 
A Chemical Symbol is a capital letter, or a capital and one small 
letter. It has four functions, namely:— 
1. It is short-hand for the name of the element. 
2. It represents one atom of the element. 
3. It stands for a constant weight of the element—the atomic 
weight or combining weight. 
4. Symbols represent single and equal volumes of gaseous ele- 
ments. 
A Chemical Formula represents a molecule either of an element 
or of a compound. It has four other functions:— 
1. It indicates at a glance the names of the elements in the 
molecule. 
2. Its symbol or symbols, together with a small figure attached 
to the foot of any symbol, show the number of atoms in the 
molecule. 
3. It stands for a constant weight of a compound—the molecular 
weight—the sum of the combining weights or of the weights 
of the atoms in the molecule. 
4. It represents two volumes of the substance, if volatilizable, 
in the state of gas or vapor, and the number of volumes 
of gaseous elements from which two volumes of any gas- 
eous compound were obtained. 
A Chemical Equation or a Chemical Diagram is a collection of 
formulae and symbols so placed on paper as to form a picture or 
illustration of the state of things before and after that metathesis 
(interchange of atoms) of molecules which results in the formation 
of molecules of new substances. 
A Solid is a substance the molecules of which are more or less 
immobile, though probably not in absolute contact. 
A Liquid is a substance the molecules of which so freely move 
about each other that it readily assumes and retains the form of 
any vessel in which it is placed. 
A Gas is a substance the molecules of which are so far apart that 
they seem to have lost all attraction for each other, and, indeed, to 
have acquired the property of repulsion to such an extent that they 
are only prevented from receding to a still greater extent by the 
pressure of surrounding matter. Motion is especially characteristic 
of gaseous fluids. 58 
GENERAL PRINCIPLES OF 
The Three Laws regulating Chemical Combination (either by 
weight or volume). 
First. A definite compound always contains the same elements 
and the same proportions of those elements—by weight or volume. 
Second. When two elements unite in more than one proportion, 
they do so in simple multiples of that proportion. 
Third. The proportions in which two elements unite with a third 
are the proportions in which they unite with each other. 
Atomic Weights are, first, the proportions in which elements are 
found to combine with each other by weight. (The figures showing 
these proportions are purely relative, but all chemists agree to make 
this relation fixed by giving the number 1 to hydrogen.) Secondly, 
they are the weights of equal volumes of elements in the state of gas 
(relative to 1 of hydrogen). 
Molecular Weights.—These are the weights of equal volumes of 
gases or vapors, under equal circumstances of temperature and pres- 
sure, and relative not to 1 but to 2 of hydrogen. In the case of non- 
volatile bodies, molecular weight is deduced from the observed 
analogies of the bodies with those whose molecular weight admits 
of proof. The molecular weight of a compound is the sum of the 
atomic weights. 
Quantivalence of Atoms.—The observed power, force, or value 
for work of an atom—relative to 1 of hydrogen. 
The Learner is recommended to read the foregoing para- 
graphs on the General Principles of Chemical Philosophy 
CAREFULLY ONCE OR TWICE, THEN TO STUDY (EXPERIMENTALLY, IF 
possible) the following pages, returning to and reading over 
the General Principles from time to time until they are thor- 
oughly COMPREHENDED. 
Minor Principles and Generalizations will be found scattered 
throughout the following pages. 
Students of pure chemistry, especially when fairly well acquainted 
with chemical facts, will also find the Principles of Chemistry, in- 
cluding the probable Constitution as distinguished from the mere 
Composition of Chemical Substances, amply set forth in Tilden’s 
“ Chemical Philosophy,” one of Longman’s series of “ Text-books 
of Science.” 
QUESTIONS AND EXERCISES. 
42. What do you understand by chemical action? Give ex- 
amples. 
43. How is chemical force distinguished from other forces ? 
44. Adduce evidence that elements exist in compounds; that sul- 
phide of iron, for instance, still contains particles of sulphur and 
iron, though it possesses properties so different from those ele- 
ments. 
45. Define the term atom. CHEMICAL PHILOSOPH Y. 
59 
46. What condition is essential for the manifestations of chemical 
force ? 
47. Can an atom exist in an uncombined state? and when are the 
atoms of an element most potent to enter into chemical combination? 
48. What is a molecule? 
49. How may the results of chemical reactions be expressed on 
paper ? 
50. Enumerate the functions of a symbol. 
51. (Jive the additional functions of a chemical formula. 
52. Describe by a diagram or an equation the reaction which en- 
sues when red-hot charcoal is plunged into oxygen gas. 
53. Draw diagrams representing the formation of P205, S02, and 
Fel2 respectively. 
54. Enumerate the differences in the physical conditions of the 
molecules in a solid, a liquid, and a gas. 
55. State the law of constant proportions. 
56. State the law of multiple proportions. 
57. State the law of reciprocal proportions. 
58. Give illustrations of the above laws. 
59. Describe the origin and use of the atomic theory. 
60. What do you understand by the atomic weight, and the mole- 
cular weight of an element? 
61. Representing the weight of an atom of hydrogen as 1, what 
will be the atomic weights of carbon, sulphur, nitrogen, and iodine? 
Give reasons for considering the stated weights to be correct. 
62. In what proportion, by volume, do elements in the gaseous 
state chemically combine? 
63. What relation exists between the combining volumes of ele- 
ments in the gaseous state and their atomic weights? Give the ex- 
planation for this. 
64. Is there any difference between the molecular volume of a 
simple or of a compound gas? 
65. Define isomorphism. 
66. Explain the value of isomorphism as evidence of atomic 
weight. 
67. What is to be understood by the quantivalencc of an element? 
Give examples of univalent, bivalent, trivalent, and quadrivalent 
atoms. 
68. How may the quantivalence of an element be expressed in its 
atomic symbol? 
69. Give the formulae of two or three compounds in which the 
quantivalence of one atom is saturated by the combined quantiva- 
lence of others. 
The reader is also recommended to question himself, or be ques- 
tioned, on the “definitions” given on pages 56, 57, and 58. 
THE ELEMENTS AND THEIR COMPOUNDS. 
Having thus obtained a general idea of the nature of such ele- 
ments as have especial interest for the medical and pharmaceutical 60 
POTASSIUM. 
student, and which indeed are all with which any student of chem- 
istry should at present occupy his attention, we may pass on to con- 
sider in detail the relations of the elements to each other. The ele- 
ments themselves, in the free condition, are seldom used in medicine, 
being nearly always associated—bound together by the chemical 
force; in this combined condition, therefore, they must be studied. 
Each combination of elements or chemical compound will, in the 
following pages, be regarded as containing two parts or roots, two 
radicals; the one usually metallic, or, to speak more generally, 
basylous; the other commonly a non-metallic, simple or complex, 
acidulous radical. The basylous radicals, or metals, will be consid- 
ered first, the acidulous radicals afterwards. Each radical wrill be 
studied from two points of view, the synthetical and the analytical: 
that is to say, the properties of an element on which the preparation 
of its compounds depends -will be illustrated by descriptions of actual 
experiments, and thus the principles of chemistry, and their appli- 
cation to medicine and pharmacy, be simultaneously learnt; then the 
reactions by which the element is detected, though combined with 
other substances, will be performed, and so the student will be in- 
structed in qualitative analysis. Synthetical and analytical reac- 
tions are, in truth, frequently identical, the object with which they 
are performed giving them synthetical interest on the one hand, or 
analytical interest on the other. 
A good knowledge of chemistry may be acquired synthetically by 
preparing considerable quantities of the salts of the different metals, 
or analytically by going through a course of pure qualitative anal- 
ysis. But the former plan demands a larger expenditure of time 
than most students have to spare, while under the latter system they 
generally lose sight of the synthetical interest which attaches to 
analytical reactions. Hence the more useful system, now offered, 
of studying each metal, etc., from both points of view, time being 
economized by the operator preparing only small specimens of 
compounds. 
Chemical synthesis and analysis, thoughtfully and conscientiously 
followed, without hurry and mere superficial consideration, but, of 
course, without undue expenditure of time, will insensibly carry 
the principles of chemistry into the mind, and fix them there in- 
delibly. 
POTASSIUM. 
Symbol K. Atomic weight 39. 
Formula K2. Probable molecular -weight 78. 
Memoranda.—The chief sources of the potassium salts* are the 
chloride found at Stassfurt, in Prussia, in the form of the mineral 
CarnallUe (chloride of potassium 50, chloride of sodium 25, and 
chloride of magnesium 25, in 100 parts); the nitrate found in soils, 
especially in warm countries; and the compounds of potassium 
* The ill-defined term salt includes most solid chemical substances, 
but more especially those which assume a crystalline form. HYDRATE OF POTASSIUM. 
61 
existing in plants. Kainit, a double sulphate of potassium and 
magnesium, also occurs among the Stassfurt minerals. The veg- 
etable salts of potassium are converted into carbonate (other salts 
are present) when the wood or other parts are burned to ashes. If 
the ashes be lixiviated with water, and the solution evaporated to 
dryness, the residue, when fused, constitutes crude potashes. The 
residue, calcined on the hearth of a reverberatory furnace till white, 
gives the product termed pearlash. Large quantities of carbonate 
are thus produced in North America and Russia, and, latterly, from 
the sugar-beet marc, in France. From the native chloride and from 
the carbonate purified by treating the pearlash with its own weight 
of distilled water, filtering and evaporating the solution until it 
thickens, and stirring constantly, “ so as to form a granular salt ” 
(Potassii Carbonas, U. S. P.), nearly all other compounds of potas- 
sium are made. Exceptions occur in cream of tartar (Potassii 
Bitartras, U. S. P.), which is the more or less purified natural 
potassium salt of the grape-vine, and in nitrate of potassium. Po- 
tassium is a constituent of between forty and fifty chemical or 
Galenical preparations of the British Pharmacopoeia. 
Carbonate of potassium is a white crystalline or granular powder, 
insoluble in alcohol, very soluble in water, rapidly liquefying in the 
air through absorption of moisture, alkaline and caustic to the taste. 
It loses all water at a red heat. Potassii Carbonas Purus, U. S. P., 
is obtained by heating the bicarbonate to redness: the resulting 
white anhydrous carbonate is converted into hydrous granular cai" 
bonate by solution in water and evaporation until a dry granular 
salt remains. 
Preparation.—Potassium itself is isolated with some difficulty by 
distilling a mixture of its carbonate and charcoal. It rapidly oxi- 
dizes in the air, and hence is always kept below the surface of min- 
eral naphtha, a liquid containing no oxygen. It crystallizes in 
octahedra. 
Qaantivalence.—The atom of potassium is univalent, K/. 
Reactions having (a) Synthetical and (b) Analytical Interest. 
(a) Synthetical Reactions. 
These are actions utilized in manufacturing preparations of potas- 
sium. The word synthesis is from avvdemg (,sttnthesis), a putting to- 
gether, as opposed to analysis, from avaAvu (analuo), I resolve. 
First Synthetical Reaction.—Boil together, for a few minutes, 
in a test-tube, five or six grains of carbonate of potassium 
(K2C03) and a like quantity of slaked lime (Ca2HO) with a 
small quantity of water. Set the mixture aside in the test-tube 
rack till all solid matter has subsided. 
Hydrate of Potassium. Caustic Potash. 
This liquid is a solution of caustic potash, or hydrate of potassium 
(KUO). Made of a prescribed strength (about 5 per cent.: sp. gr. 
1.036), it forms the Liquor Potassce, U. S. P. 62 
HYDRATE OF POTASSIUM. 
The mixture is known to be boiled long enough when a little of 
the clear liquid, poured into another test-tube and warmed, gives no 
effervescence on the addition of an acid (sulphuric, hydrochloric, or 
acetic)—a test whose mode of action will be explained hereafter. 
In the United States Pharmacopoeia the carbonate of potassium 
for this operation is directed to be obtained by boiling a solution of 
the bicarbonate until effervescence ceases; that is, until the bicar- 
bonate is almost entirely converted into carbonate. 
Best Method of expressing Decompositions.—This will be easy of 
comprehension if what has already been stated concerning symbols 
.and formulae, on pages 31 to 42, has been carefully and thoughtfully 
considered. The best means of showing on paper the action which 
occurs when chemical substances attack each other is by the employ- 
ment either of equations or diagrams, setting forth the formulae of 
the molecules concerned in the reaction. In an equation the form- 
ulae of the salts used are written on one line, the sign of addition 
(-)-) intervening; the sign of equality (— ) follows, and then the 
formulae of the salts produced, also separated by a plus sign (+). 
Thus:— 
K2C03 + Ca2II0 = 2KII0 + CaC03. 
In this reaction (the operation just performed) the metals of the 
molecules of the two salts change place: from K2C03 and Ca21IO 
there are produced CaC03 and KIIO (two molecules, 2KIIO); from 
carbonate of potassium and hydrate of calcium there result car- 
bonate of calcium (the insoluble portion) and hydrate of potassium 
(in solution).* 
In constructing a diagram or pictorial illustration of a chemical 
reaction (the reaction, for instance, just described), first the formulae 
of the salts used are written under each other on the left side of the 
leaf of a note-book, thus:— 
k2co3 
Ca2II0 
Such formulae are, in this Manual, always given with the descrip- 
tion of the reaction. Secondly, on the right is then written the 
formula of the chief substance produced, thus:—- 
* If the student is already accustomed to the use of ordinary equa- 
tions, he may pass on to Note 1, on page 64. If not, the author would 
strongly recommend the temporary employment of diagrams for ex- 
pressing chemical changes. Indeed, the occasional, if not the regular, 
use of graphic equations or diagrams is of advantage to all students. 
For while equation or diagram equally well records the formulae of 
the salts concerned in the whole reaction, the diagram alone suggests 
the mode in which its writer believes the respective atoms to change 
their positions. In the paragraphs succeeding the above, detailed ex- 
planations are given respecting the use and construction of diagrams. HYDRATE OF POTASSIUM. 
K2C03 
KIIO 
Ca2II0 
Thirdly, the formation of this chief body under consideration, 
that is to say, both the origin of its elements and their destina- 
tion, is traced out by the help of brackets which show the source 
of the elements, and converging lines which suggest the approach 
and final union of the elements, thus:— 
K2C03 
K 
_ KIIO 
Ca2II0 
110 
At this stage (at other stages, perhaps, in other reactions) the 
reader’s own intelligent power of thought and reflection must come 
into exercise. He must reason somewhat as follows: “ I am con- 
verting, and entirely converting, a quantity of carbonate of potas- 
sium into hydrate of potassium. A molecule, the smallest quantity 
I can picture on paper, of the carbonate of potassium (K2C03) con- 
tains, I am told, two atoms of potassium (K„), and a molecule of the 
hydrate (KHO), one atom (K). Therefore each molecule of the car- 
bonate (K2C03) will furnish two molecules of the hydrate (2KH0). 
Moreover, I notice that in the formula of a molecule of the hydrate 
of calcium (slaked lime) l employ, there are 2 of the HO (that is, 
2110), and this fact confirms me in the deduction that one molecule 
of the carbonate affords twro molecules of the hydrate.” The pupil 
will then amend his diagram, thus:— 
k2co3 
K2 
2KII0 
2110 
Ca2II0 
Fourthly, the question as to what becomes of the other elements 
must be cleared up. Indeed, when the reader remembers that he is 
studying this reaction for the aid it affords him in learning chemis- 
try, and not because he is desirous of manufacturing caustic potash, 
he will see that this latter part of the reaction is quite as important 
as the former. To complete the diagram, then, he must first know 
what other compound is produced and its formula. The context of 
his Manual will generally afford this information, or, after a little 
experience is acquired, analogies or his own knowledge will suggest 
correct formulae. In this case carbonate of calcium is produced, HYDRATE OF POTASSIUM. 
CaC03. (This product is, in fact, precipitated chalk, together with 
any excess of slaked lime and any natural impurities in the slaked 
lime. Pure u precipitated chalk” is made by an analogous reaction 
described subsequently.) 
The source of the elements of the carbonate of calcium, and, 
finally, their union, must be indicated just as the source and mode 
of formation of the potash were indicated. That is to say, after the 
formula of this second substance produced (CaC03) is written on the 
right of the diagram, thus :— 
k2co3 
k2 
2KII0 
Ca2II0 
2110- 
CaC03 
the source of its elements is shown by writing the symbols for those 
elements on the right of the bracket attached to the formula con- 
taining the symbols of the elements, thus :— 
K2C03 
K, 
co3 
2KII0 
2110 
Ca 
Ca2II0 
CaC03 
Lines converging from the symbols of the elements and uniting at 
the formula of the substance are then drawn, to suggest approach 
of the atoms of the elements and their union to form a molecule of 
the compound. The diagram will now be complete, thus:— 
k2co3 
k2 
C03 
KUO 
2IIO 
Ca - 
Ca2II0 
CaCo3 
The formation of a third product or a fourth product would be 
indicated in a similar manner. 
Note 1.—It will be seen that the chief data required in making 
either equationary or diagrammatic notes of decompositions are the 
symbolic formulae of the various compounds employed and produced. 
These formulae are, in this Manual, given whenever necessary. 
Chemists obtain them in the first instance by help of quantitative 
analysis. By the same means is obtained a check on the proba- 
bilities respecting the relative number of molecules concerned in a 
reaction. HYDRATE OF POTASSIUM. 
65 
Note 2.—While an equation or a diagram is an attempt to picture 
the reaction which ensues when molecules of different substances act 
upon one another, it necessarily only represents two or a minimum 
number of the molecules. The student will, of course, understand 
that what is true of these two or three molecules is true of the thou- 
sands or millions of molecules forming the mass or whole quantity 
of material on which he experiments. 
Note on Nomenclature.—Hydrates are bodies indirectly or 
directly derived from water by one-half of its hydrogen becom- 
ing displaced by an equivalent quantity of another radical. 
Thus, a piece of potassium thrown on to water (IIIIO) in- 
stantly liberates hydrogen, hydrate of potassium (KHO) being 
formed. The temperature produced at the same time is suffi- 
ciently high to cause ignition of the hydrogen, which burns 
with a purple flame (owing to the presence of a little vapor of 
potassium), while the hydrate of potassium remains dissolved 
in the bulk of the water. This radical or root or group of 
elements (HO), common to all hydrates, is sometimes termed 
hydroxyl. Water might be termed hydrate of hydrogen or 
hydroxylide of hydrogen. 
Explanation.—With regard to the group of atoms repre- 
sented by the symbols CO, and HO, only a few words need be 
said here. The former (CO,) is the grouping (root or radical) 
found in all carbonates; it is termed the carbonic radical, and 
is as characteristic of carbonates as-potassium (K) is of potas- 
sium salts. HO (hydroxyl) is characteristic of all hydrates. 
CO, is a bivalent root, HO is univalent; hence CO, is found 
united with two univalent atoms, as in carbonate of potassium, 
K,CO„ or with one bivalent atom, as in carbonate of calcium, 
CaCO,; and HO is found united in single proportion with 
univalent atoms, as in hydrate of potassium, KHO, or in double 
proportion with bivalent atoms, as in hydrate of calcium, 
Ca2HO. The quantivalence of a metal has only to be learnt, 
and the formulae of its carbonate and hydrate are ascertained 
without seeing the formula of either. The formulae of all other 
metallic salts are constructed on the same principle. But, be- 
yond committing to memory the formulae and quantivalence of 
the various groupings characteristic of carbonates, hydrates, 
nitrates, sulphates, acetates, etc. (see the following Table), 
special attention should not at present be devoted to the sub- 
ject of the constitution of salts, but restricted to what may be 
called the metallic or basylous side of salts. The formulae and 
quantivalence of the chief acidulous groupings referred to and 
the symbols and quantivalence of allied elementary bodies are 
included in the following Table :— 66 
THE METALLIC RADICALS. 
Formulag and Quantivalence of Acidulous Radicals. 
All chlorides contain ... Cl 
“ bromides “ Br 
“ iodides “ ... I 
“ cyanides “ ... CN 
“ hydrates “ ... HO 
“ nitrates “ . . . N03 
“ chlorates “ ... Cl(i3 
“ acetates “ ... C2H302 
Univalent 
radicals. 
“ oxides “ . . . O 
“ sulphides “ . . . S 
“ sulphites “ ... S03 
“ sulphates “ ... S04 
“ carbonates “ ... C03 
“ oxalates “ . • . C204 
“ tartrates “ ... C4H406 
Bivalent 
radicals. 
“ citrates “ ... C6II507 
“ phosphates “ ... P04 
“ borates “ ... B03 
Trivalent 
radicals. 
Radicals.—The above elements and compounds are termed 
radicals, each being the common root (radix) in a series of 
salts. Why compound radicals (as N03, S04, P04, etc.) differ 
in quantivalence cannot well be explained. Their constituent 
atoms doubtless always exert the same amount of attractive 
force, nearly but not quite all this force being exerted in re- 
taining the atoms in one group, and the remainder probably 
determining the quantivalence. Some of the compound radi- 
cals are obtainable in the free state, others have yet to be 
proved capable of isolated existence.* 
Pure Solution of Potash.—Solution of potash generally con- 
tains a trace of alumina dissolved from the lime by the hot 
alkali, but not enough to interfere with the use of the liquid in 
medicine. If the solution is required for analytical purposes, 
it may be obtained free from alumina by avoiding the employ- 
ment of heat, in the manner suggested by lledwood. Half a 
gallon is made by mixing half a pound of slaked lime with 
about three pints of water, placing the mixture in a half-gallon 
bottle, and adding to it, in small quantities at a time, a solu- 
tion of half a pound of carbonate of potassium dissolved in the 
other pint of water, shaking the mixture well for several 
minutes after each addition. The whole is now set on one side 
* Some modern authors term these roots radicles, a word more use- 
fully expressive of little roots or rootlets. SULPHURATED POTASH. 
67 
till clear ; and then, if a small quantity poured into a test-tube 
and warmed does not effervesce on the addition of hydrochloric 
acid, the solution is fit for use. If effervescence (clue to car- 
bonic acid gas) occurs, the mixture must be again well shaken. 
If the lime be good and recently slaked, and the bottle violently 
shaken once every half hour, the decomposition will be complete 
in about ten or twelve hours. 
Solid Potash.—Solution of potash evaporated to dryness in a sil- 
ver or clean iron vessel and the residue fused and poured into moulds 
constitutes Potassa, U. S. P. It often contains chlorides, detected 
by nitrate of silver; sulphates, detected by a barium salt, as de- 
scribed subsequently in connection with hydrochloric and sulphuric 
acids : and silica, which is precipitated on adding a strong solution 
to twice the quantity of alcohol. Liquor Potassa?, U. S. P., may be 
made by dissolving 56 parts of this hydrate in 944 of distilled water, 
or a corresponding quantity of potassa of any strength in water so as 
to make 1000 parts by weight. Potassa cum (Juice, U. S. P., is a gray- 
ish-white powder, made by rubbing together equal weights of solid 
potash and quicklime. 
Sulphurated Potash. 
Second Synthetical Reaction.—Into a test-tube put a few 
grains of carbonate of potassium previously mixed with half 
its weight of sulphur. Heat the mixture gradually until it 
ceases to effervesce. The resulting fused mass poured on a 
slab and quickly bottled is the Potassa Su/phurata, Sulphur- 
ated Potassa, U. S. P. 
Carbonate of 
potassium. 
3KaC0, + 4S2 = K„S203 + 2K2S3 + 3C02 
Sulphur. 
Hyposulphite 
of potassium. 
Sulphide of 
potassium. 
Carbonic 
acid gas. 
As met with in pharmacy this salt is not a single definite chem- 
ical compound, but a mixture of several; in short, its chemical 
character is well indicated by its vague name. AVhen fresh, and if 
carefully prepared with the official proportions of dry ingredients, it 
is of the color of liver (whence the old name “liver of sulphur”), 
and consists, as shown by J. Watts, of the salts mentioned in the 
foregoing equation, together with a little undecomposed carbonate 
of potassium, with perhaps higher sulphides of potassium (K2S4 
and K2S3); but, rapidly absorbing oxygen from the air, it soon be- 
comes green and yellow, sulphite (K2S03) and sulphate of potassium 
(K2S04) are formed, and ultimately a useless mass of dirty-white 
color results, consisting of sulphate and hyposulphite, with generally 
some carbonate of potassium and free sulphur. Moreover, if over- 
heated in manufacture, the hyposulphite 4(K2S203) is decomposed 
into sulphate 3(K2S04) and sulphide (K2S5) of potassium. Recently 
made, “ about three-fourths of its weight are dissolved by rectified 
spirit.” It is occasionally employed in the form of ointment, 68 
THE METALLIC RADICALS. 
“On triturating together 10 parts of Sulphurated Potassa and 
12.69 parts *of crystallized sulphate of copper with 60 parts of 
water, and filtering, the filtrate should remain unaffected by hydro- 
sulphuric acid (presence of at least 56 per cent, of true sulphide of 
potassium).” U. S. P. 
The extremely, indeed most unusually, complicated nature of the 
reaction, will probably cause failure to any attempt by a student to 
draw out an equation or a diagram of the reaction without the aid 
of the printed equation given above. He may therefore content 
himself, in this case, by introducing into his note-book a diagram 
founded directly on the equation and on the numbers of molecules 
there stated. With this printed equation, and the details of con- 
struction of diagrams given in connection with the first synthetical 
reaction, he will be able to give a diagram of this second synthet- 
ical reaction whthout troubling his reasoning powers, while at the 
same time he will be familiarizing himself with the more mechanical 
portions of a diagram. 
In preparing large quantities of sulphurated potash, the test-tube 
is replaced by an earthenware vessel termed a crucible (from crux, 
a cross, for originally a cross was impressed upon the melting-pot 
as used by alchemists and goldsmiths; others derive the word from 
crux, an instrument of torture, the sense here being symbolical). 
Heating Crucibles.—Crucibles of a few ounces’ capacity may be 
heated in an ordinary grate-fire. Larger ones require a stove with a 
good draught—that is, a furnace. Even the smaller ones are more 
conveniently and quickly heated in a furnace. Half-ounce or one- 
ounce experimental porcelain crucibles may be heated in a spirit- or 
gas-flame; the air-gas flame already described being generally the 
most suitable. 
Fig. 12. 
Fig. 13. 
Fig. 14. 
Crucibles of various forms. 
Acetate of Potassium. 
Third Synthetical Reaction.—Place ten or twenty or more 
grains of carbonate of potassium in a small dish, and saturate 
(satur, full) with acetic acid; that is, add acetic acid so long 
as effervescence is thereby produced; the resulting liquid is a 
strong solution of acetate of potassium. ACETATE OF POTASSIUM. 
69 
Evaporate most of the water in an open dish (see Figs. 15, 
16), stirring with a glass rod* to promote the evolution of 
vapor; a white salt remains, which fuses on the further appli- 
cation of heat. This is the official Acetate of Potassium 
(Fotassii Acetas, U. S. P.). Tf fused in the open vessel the 
acetate is liable to become slightly charred and discolored; 
this is prevented by transferring the solid residue to a test- 
tube or Florence flask before finally fusing. It forms a white, 
deliquescent, foliaceous, satin-like mass, neutral to test-paper, 
and wholly soluble in spirit. A ten per cent, solution in water 
forms the “ Solution of Acetate of Potash,” B. P. 
K2C03 + 2HC2HA = 2KC/1IA + H20 + C02 
Carbonate of 
potassium. 
Acetic 
acid. 
Acetate of 
potassium. 
Water. 
Carbonic 
acid gas. 
Explanation of Formulas.—The formula for one molecule of 
acetic acid (the acetate of hydrogen) is HC2II302, and one of 
acetate of potassium, KC2H302. The grouping, C2II302, is cha- 
racteristic of all acetates; it is univalent, and may be shortly 
though less instructively written A. 
Explanation of Process.—When two molecules of acetic acid 
(2HC2H302) and one of carbonate of potassium (K2C03) react, two 
molecules of acetate of potassium (2KC2II302) and one of carbonic 
acid (H2COs) are produced, the latter at once splitting up into water 
(1I20) and carbonic acid gas (C02), as already shown in the equa- 
tion. 
Diagram of the Reaction.—The nature of the above operation is 
indicated by an equation; it (and succeeding reactions) should be 
expressed in the student’s note-book as a diagram, and, if possible, 
without the aid of the equation. 
Note.—The above reaction has a general as well as a special syn- 
thetical interest. It represents one of the commonest methods of 
forming salts, namely, the saturation of an acid with a carbonate. 
Carbonates added to acetic acid yield acetates, to nitric acid nitrates, 
to sulphuric acid sulphates. Many illustrations of this general pro- 
cess occur in pharmacy. 
Evaporation of water from a liquid is best conducted in 
wide shallow vessels rather than in narrow deep ones, as the 
steam can thus quickly diffuse into the air and be rapidly con- 
veyed away; hence a small round-bottomed basin, heated as 
shown in Fig. 15, is far more suitable than a test-tube for such 
operations. On the manufacturing scale, iron, or iron lined 
with enamel or semi-porcelain, copper, tinned copper, or solid 
* Glass rod is usually purchased in the form of long sticks. The 
pieces may be cut to convenient lengths of from 6 to 12 inches (vide 
p. 17), sharp ends being rounded off by holding in a flame for a few 
minutes. 70 
TIIE METALLIC RADICALS. 
tin pans are used. Up to 12 or 18 inches diameter, pans, 
basins, or dishes, made of Wedgwood ware or porcelain com- 
position (Fig. 16), may be employed. Small dishes may be 
Fig. 15. 
Fig. 16. 
Evaporation from small and large basins. 
supported by retort-stands (Fig. 15), larger by cylinders (Fig. 
10), to which the dish is, if less in diameter than the cylinder, 
adapted by such flat rings or diaphragms as are shown in the 
figure. 
Bicarbonate of Potassium. 
Fourth Synthetical Reaction.—Make a strong solution of 
carbonate of potassium by beating in a test-tube a mixture of 
several grains of the salt with rather less than an equal weight 
of water. Through the cooled solution pass carbonic acid gas 
slowly but continuously; after a time a white crystalline pre- 
cipitate of Acid Carbonate or Bicarbonate of Potassium 
(KHCOa), Potassii Bicarbonas, U. S. P., the Bicarbonate of 
Potash of old Pharmacopoeias, will be formed. 
Carbonate of 
potassium. 
K2C03 + FLO + CO, = 2KHC03 
Water. 
Carbonic 
acid gas. 
Bicarbonate 
of potassium. 
The carbonic acid gas necessary for this operation is to be pre- 
pared from marble, though it might be obtained from any carbonate. 
Thus the previous synthetical reaction could be made available for 
this purpose, the carbonic acid gas evolved on the addition of the 
acetic acid to the carbonate of potassium being conducted into a 
strong solution of more carbonate of potassium by a glass tube bent 
and fitted as described when treating of oxygen gas. But motives 
of economy induce the use of carbonate of calcium, the form known 
as marble being always employed. Economy and convenience also 
cause hydrochloric acid to be used in preference to acetic or any 
other. BICARBONATE OF POTASSIUM. 
71 
Generate the carbonic acid gas by adding common hydro- 
chloric acid, diluted with twice its bulk of watdr, to a few 
fragments of marble contained in a test-tube or small flask, and 
conduct the gas into the solution of carbonate of potassium by 
a glass tube bent to a convenient angle or angles, and fitted to 
the test-tube by a cork in the usual way. (See Fig. 10, though 
no heat is necessary.) The tube may be replenished with 
marble, or acid, or both, when the evolution of gas is becoming 
slow. In working on any larger quantity than a few grains of 
the carbonate, a wide delivery-tube should be employed, or the 
end of the narrow tube occasionally cleared from any bicar- 
bonate that may have been deposited in it. The more eco- 
nomical official arrangements of the apparatus employed in this 
process will be described under the corresponding sodium salt. 
Deposition of the Bicarbonate explained.—Bicarbonate of potas- 
sium is to a certain extent soluble in water; but as it is less so than 
the carbonate of potassium, and as a saturated solution of the latter 
has been used, the precipitation of a part of the bicarbonate inevita- 
bly occurs. In other words, the quantity of water present is suffi- 
cient to keep the carbonate, but insufficient to retain the equivalent 
quantity of bicarbonate, in solution. 
Propen-ties.—Prepared on the large scale, bicarbonate of potassium 
occurs in colorless, non-deliquescent, right rhombic prisms; it has a 
saline, feebly alkaline, non-corrosive taste. Heated to redness, it 
loses 31 per cent of its weight, and is converted into carbonate 
(K2(J03), water (II20), and carbonic acid gas (C02). 
2kiico3 = k2co3 + ir2o + co2 
2)200 
100 
2)138 
69 
2)18 
9 
2)44 
22 
The foregoing equation and accompanying molecular weights (see 
page 54) show how bicarbonate of potassium, the molecular weight 
ol which happens to be just 100, must lose 31 per cent, when com- 
pletely decomposed by heat. By ebullition of its solution it also is 
soon almost wholly changed to carbonate. 
Effervescing Solution of Potash.—A solution of 30 grains of bi- 
carbonate of potassium in one pint of water, charged with 7 times 
its bulk (often less of carbonic) acid gas by pressure, constitutes the 
ordinary “potash-water,” the so-called Liquor Potasses Effervescens1 
31 
botes on Nomenclature.—The prefix hi- in the name “ bicarbonate 
of potassium ” serves to recall the fact that to a given amount of 
potassium this salt contains twice as much carbonic radical as the 
carbonate. The salt is really a “ carbonate of potassium and hydro- 
gen ” (KIIC03) ; it is intermediate between carbonate of potassium 72 
THE METALLIC RADICALS. 
(K2C03) and carbonate of hydrogen, or true carbonic acid (II2C03); 
it is “acid carbonate of potassium” or “hydric potassium carbonate.” 
Hence in constitution it is an acid salt, although not acid to the 
taste. 
Salts whose specific names end in the syllable “ ate" (carbonate, 
sulphate, etc.) are in general conventionally so termed when they 
contain an acidulous radical, or the characteristic elements of an 
acid whose name ends in “ ic," and from which acid they have been 
or may be formed. Thus the syllable “ ate," in the words sulphate, 
nitrate, acetate, carbonate, etc., indicates that the respective salts 
contain a radical whose name ended in ic, the previous syllables, 
sulph-, nitr-, acet-, carbon-, indicating what that radical was—the 
sulphuric, nitric, acetic, or carbonic. Occasionally a letter or syl- 
lable is dropped from or added to a word to render the name more 
euphonious; thus the sulphuric radical forms sulphates, not sul- 
phurates. 
Citrate of Potassium. 
Fifth Synthetical Reaction.—Dissolve a few grains or more 
of bicarbonate (or 8 parts) of potassium in water, and add (6 
parts of) citric acid (II3C6I1507) until it no longer causes effer- 
vescence. The resulting liquid is a solution of citrate of potas- 
sium (K3C6II507) (Liquor Potassii Citratis, U. S. P., sp. gr. 1.059). 
Evaporated to dryness, in an open dish, a pulverulent or granular 
residue is obtained, which is the official Potassii Citras, U. S. P., 
a white deliquescent powder. 
3KHCOs + H,C6H507 - K3C6H507 + 3H,0 + 3C02 
Carbonate of 
potassium. 
Citric acid. 
Citrate of 
potassium. 
Water. 
Carbonic 
acid gas. 
Citrates.—The citric radical or group of elements, which with 
three atoms of hydrogen forms a molecule of citric acid, and with 
three of potassium citrate of potassium, is a trivalent grouping; 
hence the three atoms of potassium in a molecule of the citrate. 
The full chemistry of citric acid and other citrates will be subse- 
quently described. 
Nitrate of potassium (K NO.,) (Potassii Nitras, U. S. P.) and Sul- 
phate of potassium (K2S04) (Potassii Sulphas, U. S. P,) could ob- 
viously also be made by saturating nitric acid (IIN03), and sul- 
phuric acid (H2S04), respectively, by carbonate of potassium. Prac- 
tically, they are not made in that way—the nitrate occurring, as 
already stated, in nature, and the sulphate as a by-product in many 
operations. Both salts will be hereafter alluded to in connection 
with nitric acid. 
Tartrate of Potassium. 
Sixth Synthetical Reaction.—Place a few grains of car- 
bonate of potassium in a test-tube with a little water, beat 
to the boiling-point, and then add acid tartrate of potassium 
(KHC4H406 or KHT) till there is no more effervescence; a IODIDE OF POTASSIUM. 
73 
solution of neutral tartrate of potassium (K2T) results, the 
Potassii Tartras of the United States Pharmacopoeia, the old 
“Soluble Tartar.” Crystals (4- or 6-sided prisms) may be 
obtained on concentrating the solution by evaporation and 
setting- the hot liquid aside. Larger quantities are made in 
the same way, 20 of acid tartrate and 9 of carbonate (with 50 
of water) being about the proportions necessary for neutrality. 
2KHC4H406 + K2COs = 2K2C4H406 + H20 + CO* 
Acid tartrate of 
potassium. 
Carbonate of 
potassium. 
Neutral tartrate 
of potassium. 
Water. 
Carbonic 
acid gas 
Tartrates.—C4II40B are the elements characteristic of all tar- 
trates 5 they form a bivalent grouping; hence the formula of the 
hydrogen tartrate, or tartaric acid, is II204II406; that of the potas- 
sium tartrate K2C4H406; of the intermediate salt, the acid potas- 
sium tartrate (cream of tartar), KIIC4II406. If the acid tartrate of 
one metal and the carbonate of another react, a neutral dimetallic 
tartrate results, as seen in Rochelle salt (KNaC4lI40B, 4HaO), the 
Soda Tartarata of the British Pharmacopoeia (Potassii et Sodii 
Tartras, U. S. P.). 
Add salts (e. g. KIIC4II40B), that is, salts intermediate in compo- 
sition between a normal or neutral salt (e. g. K2C41I40B) and an acid 
(e. g. H2C4H4Ob), will frequently be met with. All acidulous radi- 
cals, except those which are univalent, may be concerned in the for- 
mation of such acid salts. 
Iodide of Potassium 
Seventh Synthetical Reaction.—To a solution of potash, heated 
in a test-tube, or flask, or an evaporating-basin, according to 
quantity, add a small quantity of solid iodine. The deep color 
of the iodine disappears entirely. This is due to the formation 
of the colorless salts, iodide of potassium (KI) and iodate of 
potassium (KI03), which remain dissolved in the liquid. Con- 
tinue the addition of iodine so long as its color, after a few 
minutes’ warming and stirring, disappears. When the whole 
of the potash in the solution of potash has been converted into 
the salts mentioned, the slight excess of iodine remaining in 
the liquid will color it, and thus show that this stage of the 
operation is completed. 
6KH0 + 31, = 5KI + KI03 + 3IL0 
Hydrate of 
potassium. 
Iodine. 
Iodide of 
potassium. 
Iodate of 
potassium. 
Water. 
Separation of the Iodide from, the lodate.—Evaporate the 
solution to dryness. If each salt were required, the resulting 
solid mixture might be digested in spirit of wine, which dis- 
solves the iodide, but not the iodate. But the iodide only is 
used in medicine. Mix the residue, therefore (reserving a 74 
THE METALLIC RADICALS. 
grain or two for a subsequent experiment), with about a twelfth 
of its wreight of charcoal, and gently heat in a test-tube or 
crucible until slight deflagration ensues.* 
The crucible may be held in a spirit or air-gas flame, or 
other fire, by tongs. (Scissors-shaped and other “ crucible- 
tongs ” are sold by all makers of apparatus.) Under these 
circumstances the iodide remains unaffected; but the iodate 
loses all its oxygen, and is thus also reduced to the state of 
iodide. 
2KI0, + 3C2 = 2KI + 6C0 
Iodate of 
potassium. 
Carbon. 
Iodide of 
potassium. 
Carbonic 
oxide. 
Treat the mass with a little water, and filter to separate ex- 
cess of charcoal; a solution of pure iodide of potassium results. 
(Potasxii Iodidum, U. S. P.) The latter may be used as a re- 
agent or it may be evaporated to a small bulk and set aside to 
crystallize. 
“ Solution of Iodate of Potassium ” is official (B. P.) as a test- 
liquid. 
Properties.—Iodide of potassium crystallizes in small cubical crys- 
tals, very soluble in water, less so in spirit. One part in twenty of 
water forms “Solution of Iodide of Potassium,” l . S. P. Exposed 
to air and sunlight, pure iodide of potassium becomes slightly brown 
owing to the liberation of iodine. Under these circumstances a little 
carbonate of potassium is produced by action of the atmospheric 
carbonic acid and a little hydriodic acid (HI) is set free, and the 
latter, attacked by oxygen, yields a trace of water and of free iodine. 
The ozone in the air (see “ Ozone ” in Index) may also contribute to 
the liberation of iodine from such compounds as iodide of potassium. 
The addition of charcoal in the above process is simply to facili- 
tate the removal of the oxygen of the iodate of potassium. Iodate 
of potassium (KI03) is analogous in constitution, and in composition, 
so far as the atoms of oxygen are concerned, to chlorate of potassium 
(KCIO.,), which has already been stated to be more useful than any 
other salt for the actual preparation of oxygen gas itself. Hence the 
removal of the oxygen of the iodate might be accomplished by heat- 
ing the residue without charcoal. In that case the liberated oxygen 
* If, in the operation of heating iodate of potassium with charcoal, 
excess of the latter be employed, slight incandescence rather than 
deflagration occurs; if the charcoal he largely in excess, the reduc- 
tion of the iodate to iodide of potassium is effected without visible 
deflagration or even incandescence. 
Deflagration means violent burning, from fl igratits, burnt (fln/jro, I 
burn), and de, a prefix augmenting the sense of the word to which it 
may be attached. Paper thrown into a fire simply burns, nitre defla- 
grates. De-tonate (detnno) is a precisely similar word, meaning to ex- 
plode with violent noise. IODIDE OF POTASSIUM. 
would be detected on inserting the incandescent extremity of a strip 
of wood into the mouth of the test-tube in which the mixture of 
iodide and iodate had been heated. The charcoal, however, burns 
out the oxygen more quickly, and thus economizes both heat and 
time. 
Note.—The formula of iodide of potassium (KI) shows that the 
salt contains potassium and iodine in atomic proportions. A refer- 
ence to the table of atomic weights at the end of the volume, and a 
rule-of-three sum, would therefore show what weight of salt is pro- 
ducible from any given weight of iodine. 
D teetion oj Iodate in Iodide of Potassium.—Iodate of po 
tassium remaining as an impurity in iodide of potassium ma) 
be detected by adding to a solution of the latter salt some 
weak acid (say tartaric), shaking, and then adding mucilage of 
starch ; blue “ iodide of starch is formed if a trace of iodate 
be present, not otherwise. By the reaction of the added acid 
and the iodate of potassium, iodic acid (HI03) is produced, 
and by reaction of the added acid and the iodide of potassium, 
hydriodic acid (III) is produced; neither of these two acids 
alone attacks starch, but by reaction on each other they give 
rise to free iodine, which then forms the blue color. This ex- 
periment should be tried on a sample of pure iodide of potas- 
sium and on a grain or two of the impure iodide reserved from 
the previous experiment. 
HlCXj + 5111 = 3H,0 + 31, 
Note on Nomenclature.—The syllable ide attached to the syllable 
iod, in the name “ iodide of potassium," indicates that the element 
iodine is combined with the potassium. An iod ate, as already ex- 
plained, is a salt containing the characteristic elements of iodic acid 
and of all iodic compounds. Salts one of whose names ends in ide 
are those which are, or may be, formed from elements. The names 
of salts which are, or may be, formed from compounds include other 
syllables, ate being one (see page 72). The only other syllable is 
ite, which is included in the names of salts which are, or may be, 
formed from acids and radicals whose names end in ous: thus hypo- 
sulphite of sodium, etc. To recapitulate: A salt, whose name ends 
in ate contains a compound acidulous radical whose name ends in ic ; 
a salt whose name ends in ite contains a compound acidulous radical 
whose name ends in ous ; a salt whose name ends in ide contains an 
element for its acidulous radical. Thus sulphide relates to sulphur, 
sulphite to the sulphurous radical, sulphate to the sulphuric radical, 
and so on with other “ides,” “ites,” or “ ates.” 
Bromide of Potassium (Potassii Bromidum, U. S. P.)—This salt 
is identical in constitution with iodide of potassium, and may be 
made in exactly the same way, bromine being substituted for iodine. 
The formula of bromic acid is IIBrO,. It will be noticed that the 
following equations are similar in character to those showing the 
preparation of iodide of potassium:— 76 
THE METALLIC RADICALS. 
Hydrate of 
potassium. 
6KH0 + 3Br2 = 5KBr + KBr03 + 3H20 
Bromine. 
Bromide of 
potassium. 
Bromate of 
potassium. 
Water. 
Bromate of 
potassium. 
2KBr03 + 3C2 = 2KBr + 6C0 
Carbon. 
Bromide of 
potassium. 
Carbonic 
oxide. 
Bromide of potassium may also be made by decomposing solution 
of bromide of iron (FeBr2) by solution of pure carbonate of potas- 
sium (K2C03), evaporating and crystallizing. 
Manganates of Potassium. 
Eighth Synthetical Reaction.—Place a fragment of solid 
caustic potash (KHO), with about the same quantity of chlo- 
rate of potassium (KC103), and of black oxide of manganese 
(Mn02) on a piece of platinum foil.* Hold the foil by a small 
pair of forceps or tongs in the flame of a blowpipe for a few 
minutes until the fused mixture has become dark green—ap- 
parently black. This color is that of manganate of potassium 
(K2MuG4). 
Hydrate of 
potassium. 
6KHO + KC103 + 3MnO, = 3K2Mn04 + KC1 + 3II20 
Chlorate of 
potassium. 
Black oxide of 
manganese. 
Manganate of 
potassium. 
Chloride of 
potassium. 
Water. 
Ninth Synthetical Reaction.—Permanganate of Potassium 
(K2Mn208) (Pot assn Permanganas, U. S. P.), which is purple, 
is obtained, or rather a solution of it, on placing the foil and 
its adherent mass in water, and boiling for a short time. 
3KvMn04 + 2 FLO = K2Mn208 + 4KHO + Mn02 
Manganate of 
potassium. 
Water. 
Permanganate 
of potassium. 
Hydrate of 
potassium. 
Hack oxide 
of manganese. 
On the large scale, the potash set free in the reaction is neutral- 
ized by sulphuric or carbonic acid, and the solution evaporated to 
the crystallizing point. Further details will be given in connection 
with manganese. 
Solutions of manganate or permanganate of potassium and of 
sodium so readily yield their oxygen to organic matter, that they 
are used on the large scale as disinfectants, under the name of 
“ Condy’s Disinfecting Fluids.” 
Synthetical Reactions bringing under consideration the remaining 
official compounds (namely, bichromate, arsenite, chlorate, cyan- 
* The foil maybe 1 inch broad by 2 ihches long. No ordinary flame 
will melt the platinum; fused caustic alkalies only slowly corrode it, and 
very few other chemical substances affect it at all; hence the same piece 
maybe used in experimenting over and over again. Most metals form 
a fusible alloy with platinum, and phosphorus rapidly attacks it, hence 
such substances, as well as mixtures likely to yield them, should be 
heated in a small porcelain crucible. MA XGAXATES OB' POTASSIUM. 
ide, ferrocyanide, and ferridcyanide of potassium) are deferred at 
present. 
(h) Reactions having Analytical Interest (Tests). 
Note.—These are reactions utilized in searching for small quanti- 
ties of a substance (in the present instance of potassium) in a solu- 
tion. They are best performed in test-tubes or other small vessels. 
Each should be expressed, in the form of an equation or diagram, in 
the student’s note-book. All previous or future equations given in 
this volume should he transferred to the note-hook in the form of 
diagrams, constructed as described on pages 63 and 64, unless the 
student can with ease construct the equations without the aid of the 
manual. 
First Analytical Reaction.*—To a solution of any salt of 
potassium (chloride,f for example) add a few drops of hydro- 
chloric acid and of a solution of perchloride of platinum 
(PtCl4), and stir the mixture with a glass rod; a yellow gran- 
ular or slightly crystalline precipitate | slowly forms. (The 
precipitate is the double chloride of platinum and potassium, 
and its composition is expressed by the formula PtCl42KCl.) 
Memoranda—When the precipitate is long in forming, it is some- 
* As already indicated, chemical reactions are scarcely analytical 
or synthetical in themselves, but, rather, performed with an analytical 
or synthetical object. Indeed, not unfrequently one and the same re- 
action is both a synthetical and an analytical reaction. Thus th:s 
first, so-called, “ analytical reaction ” is a synthetical reaction if per- 
formed with the object of preparing a specimen of the double chloride 
of platinum and potassium. It is an analytical reaction, or, rather, 
has analytical interest, if performed with the object of demonstrating 
the presence of potassium. Chemical reactions in themselves are 
operations, not so much of analysis (resolution) or synthesis (combina- 
tion) or of analysis and synthesis conjoined, as of what has sometimes 
times been termed metathesis (transposition). Molecules are not torn 
to atoms in an operation performed with an analytical object, nor are 
the atoms put together or set together in an operation (perhaps the 
same operation) performed wit!) a synthetical object: but in both 
operations the atoms of the molecules undergo metathesis, that is, 
exchange places, or are transposed. In short, chemists use the words 
“analytical” and “synthetical” in a conventional rather than a 
strictly etymological sense. 
f A few fragments of carbonate of potassium, two or three drops of 
hydrochloric acid, and a small quantity of water, give a solution ot 
chloride of potassium at once, K2C03 + 21IC1 — 2KC1 + H20 + C02. 
+ By precipitation (from prcecipito, to throw down suddenly) is simply 
meant the formation of particles of solid in a liquid, no matter whether 
the solid, the precipitate, subsides or floats. 
$ Experiments with such expensive reagents as perchloride of plat- 
inum are economically performed with watch-glasses, dr< ps of the 
liquid being operated on. 78 
THE METALLIC RADICALS. 
times of an orange-yellow tint. If iodide of potassium happen to 
be the potassium salt under examination, some iodide of platinum 
(Ptl4) will also be formed, giving a red color to the solution, and a 
larger quantity of the precipitant (that is, the precipitating agent) 
will be required. 
Precaution.—Only chloride of potassium forms this characteristic 
compound; hence, if the potassium salt in the solution is known not 
to be a chloride, or if its composition is unknown, a few drops of 
hydrochloric acid must he added, otherwise some of the perchloride 
of platinum will be utilized for its chlorine only, the platinum being 
wasted. Thus, if nitrate of potassium (KN03) be present, a few 
drops of hydrochloric acid enable the potassium to assume the form 
of chloride when the perchloride of platinum is added, nitric acid 
(IINOg) being set free. 
Explanation.—The precipitate is, practically, insoluble in water. 
It is for this reason that a very small quantity of any soluble potas- 
sium salt (or, rather, of the potassium in that salt) is thrown out of 
solution by perchloride of platinum. 
Note on Nomenclature.—When distinct molecules of salts unite 
and form a single crystalline compound, the product is termed a 
double salt. The double chloride of potassium and platinum is 
such a body. 
Second Analytical Reaction.—To any solution of any salt 
of potassium add excess of strong solution of tartaric acid 
(H2C4H406), and shake or well stir the mixture; a white gran- 
ular precipitate of acid tartrate of potassium (KHC4I1406) 
will be formed. 
Acid Tartrate of Potassium. 
Note.—By “ excess” of any test liquid (such as the “solution of 
tartaric acid” just mentioned) is meant such a quantity as is probably 
rather more than sufficient to convert the whole weight of the com- 
pound attacked into the compound produced. Thus, in the present 
case enough acid must be added to convert the whole of the potas- 
sium salt operated on into acid tartrate of potassium. What the 
weight of salt operated on was must he mentally estimated, roughly, 
by the operator. It is not necessary in analyzing to know the exact 
weights of salts employed. The analyst must use his judgment, 
founded on his knowledge of the reaction (as shown by an equation) 
and of the molecular weights of the substances employed in the 
reaction as well as by the rough estimate of the amount of material 
on which he is experimenting. 
Limits of the Test.—Acid tartrate of potassium is soluble in about 
180 parts of cold and in 6 parts of boiling water. Hence, in apply- 
ing the tartaric test for potassium, the solutions must not be hot. 
Even if cold, no precipitate will be obtained if the solutions are 
very dilute. This test, therefore, is of far less value than the first 
mentioned. The acid tartrate of potassium is less soluble in diluted 
alcohol than in water; so that the addition of spirit of wine renders 
the reaction somewhat more delicate. ACID TARTRATE OF POTASSIUM. 
79 
Cream of Tartar.—The precipitate is the Bitartrate or Acid Tar- 
trate of Potassium (Potaauii Bitartras, U. S. P.), though the official 
preparation is not formed in the above manner; on the contrary, 
the acid is derived from the salt, which, mixed with tartrate of cal- 
cium, occurs naturally in the juice of many plants. 
Memorandum.—When the tartaric acid is added to the salt of 
potassium, and the acid tartrate formed, the acid whose chief ele- 
ments were previously with the potassium is set free; and in such 
acid solutions the acid tartrate is somewhat soluble. To prevent 
loss on this account, acid tartrate of sodium, or Bitartrate of So- 
dium, U. S. P., NaIIC4H406, II20, a salt tolerably soluble in water, 
may be used as a test instead of tartaric acid (Plunkett). The 
sodium, uniting with the acidulous radical, thus gives a neutral 
instead of an acid solution. But this advantage is of less import- 
ance from the fact that more water is introduced by the saturated 
solution of acid tartrate of sodium than by a saturated solution of 
tartaric acid. 
Third Analytical Reaction.—The flame-tet. Dip the looped 
end of a platinum wire into a solution containing a potassium 
salt, and introduce the loop into the lower part of a spirit- 
flame, the flame of a mixture of gas and air, a blowpipe flame, 
or other slightly colored flame. A light violet or lavender tint 
will be communicated to the flame, an effect highly character- 
istic of salts of potassium. 
Fourth Analytical Fact.—Salts of potassium are not vola- 
tile. Place a fragment of carbonate, nitrate, or any other po- 
tassium salt, on a piece of platinum foil, and heat the latter 
in the flame of a lamp; the salt may fuse to a transparent 
liquid and flow freely over the foil, water also if present will 
escape as steam, and black carbon be set free if the salt hap- 
pen to be a tartrate, citrate, etc.; but the potassium compound 
itself will not be vaporized. This is a valuable negative prop- 
erty, as will be evident when the analytical reactions of ammo- 
nium come under notice. 
70. Name the sources of Potassium. 
71. (live the source, formula, and characters of Carbonate of 
Potassium. 
72. Distinguish between synthetical and analytical reactions. 
73. IIow is the official Liquor Potassce prepared? 
74. What is the systematic name of Caustic Potash? 
75. State the chemical formula of Caustic Potash. 
76. Construct an equation or diagram expressive of the reaction 
between Carbonate of Potassium and slaked lime. 
77. Define a hydrate. 
QUESTIONS AND EXERCISES. 80 
THE METALLIC RADICALS. 
78. What group of atoms is characteristic of all carbonates? 
79. Define the term radical. 
80. How is “ Sulphurated Potash ” made, and of what salts is it a 
mixture ? 
81. What is the formula of the acetic radical—the radical of all 
acetates ? 
82. Draw a diagram showing the formation of Acetate of Potas- 
sium. 
83. Give a general process for the conversion of carbonates into 
other salts. 
84. What is the difference between Carbonate and Bicarbonate of 
Potassium? How is the latter prepared? 
85. What is the relation between salts whose specific names end 
in the syllable u ate," and acids ending in u ic ” ? 
86. Draw out diagrams or equations descriptive of the formation 
of Tartrate of Potassium from the Acid Tartrate, and Citrate from 
the Carbonate of Potassium. 
87. Distinguish between a normal and an acid salt. 
88. How is Iodide of Potassium made? Illustrate the process 
either by diagrams or equations. 
89. Describe the appearance and chemical properties of Iodide of 
Potassium. 
90. Work out a sum showing how much Iodide of Potassium is 
producible from 1000 grains of Iodine? Ans. 1307 grains. 
91. Give a method for the detection of Iodate in Iodide of Potas- 
sium. Explain the reaction. 
92. Has the syllable “ ide" any general significance in chemical 
nomenclature ? 
93. What are the differences between sulphides, sulphites, and 
sulphates ? 
94. Mention the chemical relations of Bromide to Iodide of Potas- 
sium. y 
95. Describe the formation of Permanganate of Potassium, giving 
equations or diagrams. 
96. How do manganate and permanganate of potassium act as 
disinfectants ? 
97. Enumerate the tests for potassium, explaining by diagrams or 
equations the various reactions which occur. 
SODIUM. 
Symbol Na. Atomic weight 23. 
Formula Na2. Probable molecular weight 46. 
Memoranda.—Most of the sodium salts met with in Pharmacy 
are obtained directly from carbonate of sodium, which is now manu- 
factured on an enormous scale from chloride of sodium (common 
salt, sea-salt, bay-salt, or rock-salt), the natural source of the so- 
dium salts. When pure, salt (Sodii Chloridum, U. S. P.) occurs “ in 
small white crystalline grains, or transparent cubic crystals, free 
from moisturethe best varieties commonly contain a little chlo- SODIUM. 
81 
ride of magnesium and sometimes other impurities. Besides the 
direct and indirect use of carbonate of sodium, or carbonate of soda, 
as it is commonly called in medicine, it is largely used for house- 
hold cleansing purposes under the name of “soda,” and in the 
manufacture of soap. Nitrate of sodium also occurs in nature, but 
is valuable for it nitric constituents rather than its sodium. Sodium 
is a constituent of about forty chemical or Galenical preparations of 
the Pharmacopoeias. 
Sodium is prepared by a process similar to that for potassium, 
but with less ditiiculty. It crystallizes in octahedra. Its atom is 
univalent, Na/. 
Reactions having (a) Synthetical and (h) Analytical 
Interest. 
(«) Reactions having Synthetical Interest 
Hydrate of Sodium. Caustic Soda. 
First Synthetical Reaction.—The formation of solution of 
hydrate of sodium or caustic soda, NallO (Liquor Sodse, U. 
S. P.). This operation resembles that of making solution of 
potash already described, and its strength is the same, “ about 
5 per cent;” sp. gr. about 1.059. 
The practical student should refer to the remarks made concern- 
ing solution of potash, applying them to solution of soda, He may 
perform the corresponding experiments or omit them, as he considers 
he does or does not clearly comprehend all they are designed to teach. 
Na2C03 + Ca2II0 = 2NaII0 + CaC03 
Carbonate 
of sodium. 
Hydrate of 
calcium. 
Hydrate of 
sodium. 
Carbonate 
of calcium. 
Pure Solution of Soda, free from any trace of alumina, may be 
prepared by shaking in a Winchester quart, once every 20 or 30 
minutes for 5 or 6 hours, 14 ozs. of crystals of carbonate of sodium 
and 8 ozs. of good recently slaked lime. If solution of soda be 
evaporated to dryness, and the residue fused and poured into 
moulds, solid hvdrate of sodium (Soda, U. S. P.) is obtained. 
Common and cheap caustic soda is now largely employed in 
various manufactures. This variety is a by-product in the prep- 
aration of carbonate of sodium, but, though highly useful as a 
chemical agent, is too impure for use in medicine. The United 
States Pharmacopoeia recognizes Liquor Sodae made from solid 
caustic soda 56 parts, and distilled water 944 parts; or from 
caustic soda of any other strength if only an equivalent amount 
be used. 
Action of Sodium on Water.—Sodium, like potassium, decom- 
poses water with production of hydrate of sodium and hydrogen, 
but unless the sodium is confined to one spot by placing it on a 
small floating piece of filter paper, the action is not sufficiently 
intense to cause ignition of the escaping hydrogen. When the 82 
tup: metallic radicals. 
latter does ignite, it burns with a yellow flame, due to the presence 
of a little vapor of sodium. 
Second Synthetical Reaction.—The reaction of sulphur and 
carbonate of sodium at a high temperature resembles that of 
sulphur and carbonate of potassium; but, as the product is not 
used in medicine, the experiment may be omitted. It is men- 
tioned here to draw attention to the close resemblance of the 
potassium salts to those of sodium. 
Acetate of Sodium. 
Third Synthetical Reaction.—Add the powder or fragments 
of carbonate of sodium (Na2C03) to some strong acetic acid in 
a test-tube or evaporating-basin as long as effervescence occurs, 
and then evaporate some of the water.* When the solution 
is cold, crystals of acetate of sodium (NaC2H302,3H20) (Sodii 
Adas, U. S. P.) will be deposited. A ten per cent, solution 
in distilled water forms the “ Solution of Acetate of Soda,-’ 
B. P. 
Acetate of sodium effloresces in dry air, and loses all its 
water of crystallization when gently heated. It supports a 
temperature of 270° or 280° F. without decomposition, but 
above 300° soon chars. 
Carbonate 
of sodium. 
Na,CO-j + 2HCJIA = 2NaC2HH02 + H20 + CO, 
Acetic acid. 
Acetate of 
sodium. 
Water. 
Carbonic 
acid gas. 
Bicarbonate of Sodium. 
Fourth Synthetical Reaction.—The action of carbonic acid 
(H2C03) or carbonic acid gas (C02) and water (H20), on car- 
bonate of sodium (Na2CO;j). This resembles that of carbonic 
acid on carbonate of potassium, but is applied in a different 
manner. The result is bicarbonate of sodium (NaHC03) 
(Sodii Bicarhonas Venalis, U. S. P.). 
Carbonate 
of sodium. 
Na2C03 + H,0 + C02 = 2NaIIC0, 
Water. 
Carbonic 
acid gas. 
Bicarbonate of 
sodium. 
Process.—Heat crystals of carbonate of sodium in a porce- 
lain crucible until no more steam escapes. Hub the product, 
in a mortar, with two-thirds its weight of more of the crystals 
and place the powder in a test-tube or small bottle into which 
carbonic acid gas may be conveyed by a tube passing through 
* The “water” alluded to occurs in the acid, which, though com- 
monly termed “acetic” acid, is really a solution of that acid in water. BICARBONATE OF SODIUM. 
83 
a cork and terminating at the bottom of the vessel. To gene- 
rate the carbonic acid gas fill a test-tube having a small hole 
in the bottom (or a similar piece of glass tubing, of which one 
end is plugged by a grooved cork) with fragments of marble, 
insert a cork and delivery-tube, and connect the latter with the 
similar tube of the vessel con- 
taining the carbonate of so- 
dium by a piece of India- 
rubber tubing. Now plunge 
the tube of marble into a 
test-glass, or other vessel, 
containing a mixture of one 
part hydrochloric acid and 
two parts water, and loosen 
the cork of the carbonate-of- 
sodium tube until carbonic 
acid gas, generated in the 
marble tube, may be con- 
sidered to fill the whole arrangement; then rfp’ace the cork 
tightly and set the apparatus aside. As the gas is absorbed by 
the carbonate of sodium, hydrochloric acid rises into the marble 
tube, and generates fresh gas, which, in its turn, drives back 
the acid liquid, and thus prevents the production of any more 
gas until further absorption has occurred. When the salt is 
wholly converted into bicarbonate (NaHCOs), it will be found 
to have become damp through the liberation of water from the 
crystallized carbonate (Na,CO3,10H,O). (It would be inconve- 
niently moist, even semi-fluid, if a part of the carbonate had 
not previously been rendered anhydrous.) The Sodii Bicar- 
bonus, U. S. P., is the commercial bicarbonate purified from 
any carbonate or traces of other salts by introducing it into a 
percolator and passing water through it till the washings cease 
to precipitate a solution of sulphate of magnesium, when the 
bicarbonate of sodium is removed from the percolator and 
dried on bibulous paper in a warm place. 
The carbonate of sodium may be placed, not in a test-tube or 
bottle, but in a vertical tube the bottom of which is loosely closed 
by a grooved cork. Any water of crystallization that is "set free 
then runs off (into a basin or cup beneath), and takes with it any 
impurities (chlorides or sulphates, etc.) that may have been present 
in the original salt. 
A crystal of carbonate of sodium is carbonate of sodium plus 
water (Sodii Carbonas, U. S. P.; see “Carbonates”); on heating it, 
more or less of the water is evolved, and anhydrous carbonate of 
sodium is partially or wholly produced (Sodii Carbonas Exsiccatus, 
U. S. P.). 
Fig 17. 
Preparation of bica: bonate of sodium. 84 
THE METALLIC RADICALS. 
Na,CO,,10TI,O — 10H2O = Na,CO, 
Crystallized carbonate 
of sodium (286). 
Water 
(180). 
Dried carbonate 
of sodium (106). 
According to the United States Pharmacopoeia dried carbonate of 
sodium is to be prepared by exposing crystals of carbonate of so- 
dium to warm air for several days to effloresce, and then to a tem- 
perature of about 45° C. until half the original weight is obtained. 
286 parts would thus become 143, and the latter would thus still 
retain 37 parts of water. In other words, the dried carbonate con- 
tains 72.6 per cent, of anhydrous carbonate and 27.4 per cent, of 
water. The crystals contain, obviously, a little more than 37 per 
cent, of anhydrous carbonate and nearly 63 per cent, of water. The 
student should verify all these figures. 
Note on Nomenclature.—Anhydrous bodies (from a, a, and vdup, 
hudor, i. e. without water) are compounds from which water has 
been taken, but whose essential chemical properties are unaltered. 
Salts containing water are hydrous bodies ; of these the larger por- 
tion are crystalline, and their water is then termed water of crystal- 
lization. Non-crystalline hydrous compounds were formerly spoken 
of as hydrated substances; hydrates are, however, a distinct class 
of bodies, salts derived from water by one-half of its hydrogen 
becoming displaced by an equivalent quantity of another radical. 
Anhydrides form still another distinct class of chemical substances; 
they are derived from acids •, in short, they are acids from which, 
not exactly water as water, but the elements of Mater have been 
removed, the essential chemical (acid) properties being thereby 
greatly altered. (For illustrations, see Index, “Anhydrides.”) 
Water of Crystallization.—The Mater in crystallized carbonate 
of sodium is in the solid condition, and, like ice and other fusible 
substances, requires heat for its liquefaction. Many salts (freezing- 
mixtures), M'hen dissolved in M'ater, give a very cold solution. This 
is because they and their solid water, if they have any, are then, 
absorbing some heat from surrounding media, converted into liquids. 
Take aMray from water some of its heat, the result is ice. Give to ice 
(at 32° F.) more heat than it contains already, the result is Mater 
(still at 32° F.). (Heat thus taken into a substance M'ithout increas- 
ing its temperature is said to become latent—from latens. hiding; it 
is no longer discoverable by the sense of touch or the thermometer. 
The term latent gives a somewhat incorrect idea, however, of the 
process ; for our knoM'ledge of the extent and readiness M'ith which 
one form of force is convertible into another renders highly probable 
the assumption that heat is in these cases converted into motion, the 
latter enabling the molecules of a solid to take up the new positions 
demanded by their liquid condition.) The only apparent difference 
between ice and the M'ater in such crystals as carbonate of sodium is 
that ice is solid M ater in the free, and Mrater of crystallization solid 
water in the combined state. The former can only exist at and beloM' 
32° F.; the latter may exist at ordinary temperatures. Many salts, 
hoM'ever, which unite M'ith little or even no M'ater of crystallization 
at common temperatures, take up much, according to Guthrie, at very 
low temperatures, and such salts he calls cryohydrates (xpvoc, kruos, TARTRATE OF POTASSIUM AND SODIUM. 
85 
icy cold, frost). On the other hand, all water of crystallization is 
dispelled at high temperatures. In chemical formulae, the symbols 
representing water are usually separated by a comma from those 
representing salts. The crystals of acetate of sodium (of the third 
reaction) contain water in this loose state of combination—water of 
crystallization (NaC2H302,3H,0).. 
“ Soda-water.''''—A solution of bicarbonate of sodium in water 
charged with carbonic acid gas under pressure constitutes the offi- 
cial Liquor Sodce Effervescens, B. P., and, like the “ potash-water ” 
of the shops, is a true medicine, an antacid. Ordinary “soda-water,” 
however, is in many cases simply a solution of carbonic acid gas in 
water, and would be more appropriately termed “aerated water:” 
any medicinal effect it may possess is due to the sedative influence 
of its carbonic acid gas on the coats of the stomach. At common 
temperatures water dissolves about its own volume of carbonic acid 
gas, both being under the same pressure. One pint of the official 
soda-water contains 30 grains of bicarbonate of sodium and a pint 
of carbonic acid gas; but the solution is under a pressure of seven 
atmospheres, so that seven pints of the gas at ordinary atmospheric 
pressure are required for the quantity mentioned. 
Solubility of Gases in Water.—Whatever the weight and volume 
of a gas dissolved by a liquid at ordinary atmospheric pressure, that 
weight is doubled by double pressure, the two volumes of gas thereby 
being reduced to one, trebled at treble pressure, the three volumes of 
gas being reduced to one, quadrupled at quadruple pressure, the four 
volumes of gas being reduced to one, and so on. This is a general 
law (Henry and Dalton) regarding the solubility of gases in liquids 
under given temperatures. An average bottle of “ soda-water ” con- 
tains about four times the weight of carbonic acid gas which can 
exist in it without artificial pressure, so that on removing its cork 
three times its bulk escapes, its own bulk remaining dissolved. 
Tartrate of Potassium and Sodium. 
Fifth Synthetical Reaction.—To some hot strong solution of 
carbonate of sodium (about three parts) in a test-tube or larger 
vessel add acid tartrate of potassium (about four parts), till no 
more effervescence occurs; when the solution is cold, crystals 
of the tartrate of potassium and sodium (Potasni et Sodii Tar- 
tras, U. S. P.), the old Rochelle Salt, will be deposited— 
(KNaC4H406,4H20). The crystals are usually halves of right 
rhombic prisms. 
Na,CO» + 2KHC4H406 = 2KNaC4H406 + II20 + C02 
Carbonate 
of sodium. 
Acid tartrate 
of potassium. 
Tartrate of potas- 
sium and sodium. 
Water. 
Carbonic 
acid gas. 
Formulae op Tartrates. 
Tartaric acid TIIE C4II406 
Acid tartrate of potassium KlI C4II406 
Tartrate of potassium and sodium . . KNaC4H406 86 
THE METALLIC RADICALS. 
Very close analogy will be noticed in the constitution of the mole- 
cules of these salts. When the other tartrates come under notice, it 
will be found they also have a similar constitution. 
Hypochlorite of Sodium. 
Liquor Sodce Chlorates, U. S. P., “ Labbaraque’s Solution,” is 
made by decomposing solution of carbonate of sodium by solu- 
tion of chlorinated lime; 100 parts of the carbonate, 80 of chlo- 
rinated lime, and 820 of water. Sp. gr. 1.044. 
2Na2C03 + CaCl2,Ca2C10 = 2(NaCl,NaC10) + 2CaC0., 
Carbonate 
of sodium. 
Chlorinated 
lime. 
Other Sodium Compounds. 
Chlorinated 
soda. 
Carbonate of 
calcium. 
Synthetical Reactions portraying the chemistry of the remaining 
official compounds (namely, nitrate, sulphate, hyposulphite, borate, 
arseniate, and valerianate of sodium) are deferred until the several 
acidulous radicals of these salts have been described. 
Phosphate of Sodium.—The preparation and composition of this 
salt will be most usefully studied after bone-ash, the source of it and 
other phosphates, has been described. Bone-ash is phosphate of 
calcium (see page 109). 
The Citro-Tartrate (Sodce Citro-tartras Effervescens, B. P.) is a 
mixture of bicarbonate of sodium (17 parts), citric acid (fi), and 
tartaric acid (8), heated (to 200° or 220° F.) until the particles 
aggregate to a granular condition. When required for medicinal 
use, a dose of the mixture is placed in water; escape of carbonic 
acid gas at once occurs, and an effervescing liquid results. This 
substance may be regarded as the official representative of the pop- 
ular “ Effervescing Citrate of Magnesia,” which will be further no- 
ticed in connection with the salts of magnesium (page 118). 
Soda Powders are formed of 30 grains of bicarbonate of sodium 
and 25 of tartaric acid wrapped separately in papers of different 
color. When mixed with water, tartrate of sodium results, a little 
bicarbonate also remaining. 
In the manufacture of Carbonate of Sodium from chloride, the 
source of the sodium is chloride of sodium, and of the carbonic 
radical carbonate of calcium in the form of limestone. The chloride 
is first converted into sulphate, the sulphate is then roasted with 
coal and limestone, and the resulting black-ash lixiviated (lixivia, 
from lix, lye—water impregnated with alkaline salts: hence lixivia- 
tion, the operation of washing a mixture with the view of dissolving 
out salts). The lye, evaporated to dryness, yields crude carbonate 
of sodium (soda-ash). This process will be further described in 
connection with Carbonates. 
Deliquescence and Efflorescence.—The carbonates of sodium and 
potassium, chemically closely allied, are readily distinguished phys- 
ically. Carbonate of potassium quickly absorbs moisture from the 
air and becomes damp, wet, and finally fluid—it is deliquescent (deli- 
quescens, melting away). Carbonate of sodium, on the other hand, OTHER SODIUM COMPOUNDS. 
87 
yields some of its water of crystallization to the air, the crystals 
becoming white, opaque, and pulverulent—it is efflorescent (effaces- 
cens, blossoming forth). 
Analogy of Sodium Salts to Potassium Salts.—Other synthetical 
reactions might be described similar to those given under potassium, 
and thus citrate, iodide (Sodii Iodidum, U. S. P.), Nal, bromide 
(Sodii Bromidum, U. S. P.), NaBr, iodate, bromate, chlorate (Sodii 
Chloras, U. S. P.), NaC103, manganate and permanganate of sodium, 
and many other salts be formed. But enough has been stated to 
show how analogous sodium is chemically to potassium. Such analo- 
gies will constantly present themselves. In few departments of 
knowledge are order and method more perceptible; in few is there 
as much natural law, as much science, as in chemistry. 
Substitution of Potassium and Sodium Salts for each other.— 
Sodium salts being cheaper than potassium salts, the former may 
sometimes be economically substitued. That one is employed rather 
than the other, is often merely a result due to accident or fashion. 
But it must be borne in mind that in some cases a potassium salt 
will crystallize more readily than its sodium analogue, or that a 
sodium salt is stable when the corresponding potassium salt has a 
tendency to absorb moisture, or one may be more soluble than the 
other, or the two may have different medicinal effect. Por these or 
similar reasons, a potassium salt has come to be used in medicine 
or trade, instead of the corresponding sodium salt, and vice versa. 
Whenever the acidulous portion only is to be utilized, the least ex- 
pensive salt of the class would nearly always be selected. 
(fl) Reactions having Analytical Interest. 
1. The chief analytical reaction for sodium is the flame-test. 
When brought into contact with a flame in the manner de- 
scribed under potassium (page 79), an intensely yellow color 
is communicated to the flame by any salt of sodium. J his is 
highly characteristic—indeed, almost too delicate a test; for if 
the point of the wire be touched by the fingers, enough salt 
(which is contained in the moisture of the hand) adheres to 
the wire to communicate a very distinct sodium reaction. 
These statements should he experimentally verified, the chlo- 
ride, sulphate, or any other salt of sodium being employed. 
2. Precipitant of Sodium..—Sodium is the only metal whose com- 
mon salts are all soluble in water. Hence no ordinary reagent can 
be added to a solution containing a sodium salt which shall give a 
precipitate containing the sodium. A neutral or alkaline solution 
of a sodium salt gives, however, a granular precipitate of antimoni- 
ate of sodium (Na2H2Sb207,f>iI20) if well stirred or shaken with a 
solution of antimoniate of potassium (K2II2Sb207), but the reagent 
precipitates other metals, and is liable to decompose and become use- 
less, and hence is seldom employed. 
Antimoniate of potassium is made by adding, gradually, finely 
powdered metallic antimony to nitrate of potassium fused in a cru- 88 
THE METALLIC RADICALS. 
cible so long as deflagration continues. The resulting mass is boiled 
with a large quantity of water, the solution filtered and preserved in 
a well-stoppered bottle ; for the carbonic gas in the air is rapidly ab- 
sorbed by the solution, antimonic acid being deposited. 
3. Sodium salts, like those of potassium, are not volatile. 
Prove this fact by the means described when treating of the 
effect of heat on potassium salts (p. 79). 
QUESTIONS AND EXERCISES. 
98. How is the official Solution of Soda prepared ? Give a dia- 
gram or equation. 
99. Explain the action of sodium or potassium on water. What 
colors do these elements respectively communicate to flame? 
100. How much bicarbonate of sodium can be obtained from 
2240 pounds of crystallized carbonate of sodium? Ans. 1316 lbs., 
nearly. 
101. Acetate of Sodium : give formula, process, and equation. 
102. Give a diagram showing the formation of Bicarbonate of 
Sodium. 
103. Why is a mixture of dried and undried carbonate of sodium 
employed in the preparation of the bicarbonate ? 
104. State the difference between anhydrous and crystallized car- 
bonate of sodium. 
105. Define the terms anhydrous, hydrous, hydrate, anhydride. 
106. What do you understand by water of crystallization f 
107. What is the nature of “ Soda-water” ? 
108. How many volumes of gas (reckoned as at ordinary atmo- 
spheric pressure) are contained in any given volume of the British 
official “ Soda-water ” ? 
109. What is the general law regarding the solubility of gases in 
liquids under pressure ? 
110. What is the systematic name of Rochelle salt, and how is the 
salt prepared ? 
111. What is the relation of Rochelle salt to cream of tartar and 
tartaric acid? 
112. Give the mode of preparation and composition of Solution of 
Chlorinated Soda, and express the process by a diagram. 
113. How is the granular effervescing Citro-tartrate of Sodium 
prepared ? 
114. Define Deliquescence, Efflorescence, and Lixiviation. 
115. What is the general relation of potassium salts to those of 
sodium ? 
116. How are sodium salts analytically distinguished from those 
of potassium? 
AMMONIUM. 
Symbol XII4 or Am. Atomic weight 18. 
Memoranda.—The elements nitrogen and hydrogen, in the pro- 
portion of one atom to four (NII4), are those characteristic of all the AMMONIUM. 
89 
compounds about to be studied, just as potassium (K) and sodium 
(Na) are the characteristic elements of the potassium and sodium 
compounds. Ammonium is a univalent nucleus, root, or radical, like 
potassium or sodium ; and the ammonium compounds closely resemble 
those of potassium or sodium. In short, if, for an instant, potassium 
or sodium be imagined to be compounds, the analogy between these 
three series of salts is complete. Ammonium is said to have been 
isolated by Weyl, as an unstable dark-blue liquid possessing a me- 
tallic lustre. 
Source.—The source of nearly all the ammoniacal salts met with 
in commerce is ammonia-gas (NHS) obtained in distilling coals in 
the manufacture of ordinary illuminating gas and of coke. It is 
doubtless derived from the nitrogen of the plants from which the 
coal has been produced. It is possible, however, to produce am- 
monia from its elements. Thus, coal-dust, air, and vapor of water, 
all at a red heat, yield, according to Rickman and Thompson, gaseous 
ammonia. Salt added to the mixture prevents the further combus- 
tion of the formed ammonia, and chloride of ammonium sublimes. 
Nitrogen and hydrogen passed over spongy platinum yields traces 
of ammonia. 
Ammonia.—When this gas (NIL,) comes into contact with water 
(II20), in the process of washing and cooling coal-gas, hydrate of 
ammonium (MI4lIO, or Am IIO) is believed to be formed, the 
analogue of hydrate of potassium (KIIO) or sodium (NallO). The 
grounds for this belief are the observed analogy of the well-known 
ammoniacal salts to those of potassium and sodium, the similarity of 
action of solution of potash, soda, and ammonia on salts of most 
metals, and the existence of crystals of an analogous sulphur salt 
(NH4HS). 
Chloride of Ammonium.—The “ ammoniacal liquor ” of the gas- 
works is usually neutralized by hydrochloric acid, by which crude 
chloride of ammonium (sal-ammoniac) is produced. 
nh4ho + nci = nii4ci + n2o; 
and from this salt, purified, the others used in pharmacy are directly 
or indirectly made. Chloride of ammonium (Ammonii Chlnridum, 
L. S. P.) occurs in colorless, inodorous, translucent fibrous masses, 
tough, and difficult to powder, and as a snow-white crystalline 
powder, soluble in water [1 in 10 is the “Solution of Chloride of 
Ammonium,” U. S. P.] and in rectified spirit. Chloride of am- 
monium generally contains slight traces of oxychloride of iron, 
tarry matter, and possibly chlorides of compound ammoniums (vide 
“Artificial Alkaloids” in Index). 
Sulphate of Ammonium, (NII4)2S04, results when “ ammoniacal 
liquor” is neutralized by oil of vitriol. It is largely used as a con- 
stituent of artificial manure in England, and when purified by recrys- 
tallization is employed in pharmacy (Ammonii Sulphas, U. S. P.). 
Volcanic Ammonia.—A very pure form of ammonia is .that met 
with in volcanic districts, and obtained as a by-product in the manu- 
facture of borax ; the crude boracic acid as imported contains from 
5 to 10 per cent, of ammonium salts, chiefly sulphate, and double 90 
TIIE METALLIC RADICALS. 
sulphates of ammonium with magnesium, sodium, and manganese 
(Howard). 
Reactions having (a) General, (h) Synthetical, and 
(c) Analytical Interest. 
(a) General Reaction.—To forty or fifty grains of dry mer- 
cury in a dry test-tube, add one or two small pieces of sodium 
(freed from adhering naphtha by gentle pressure with a piece 
of filter-paper), and amalgamate by gently warming the tube. 
To this amalgam, when cold, add some fragments of chloride 
of ammonium and a strong solution of the same salt. The so- 
dium amalgam soon begins to swell and rapidly increase in 
bulk, probably overflowing the tube. The light spongy mass 
produced is the so-called ammonium-amalgam, and the reaction 
is usually adduced as evidence of the existence of ammonium ; 
the sodium of the amalgam unites with the chlorine of the 
chloride of ammonium, while the ammonium is supposed to 
form an amalgam with the mercury. As soon as formed the 
amalgam gives off hydrogen and ammonia gases; this decom- 
position is nearly complete after some minutes, and impure 
mercury remains. 
Ammonium-Amalgam. (?) 
(/>) Reactions having Synthetical Interest. 
Hydrate of Ammonium. Ammonia. 
First Synthetical Reaction.—Heat a few grains of sal-ammo- 
niac with about an equal weight of hydrate of calcium (slaked 
lime) dampened wTith a little water in a test-tube; ammonia 
gas is given off, and may be recognized by its well-known 
odor. It is very soluble in water. Pass a delivery-tube, 
fitted to the test-tube as described for the preparation of oxy- 
gen and hydrogen, into a second test-tube, at the bottom of 
which is a little water; again heat, the end of the delivery- 
tube being only just beneath the surface of the water (or, pos- 
sibly, all the water might rush into the generating-tubes, water 
absorbing ammonia gas with great avidity) ; solution of ammo- 
nia will be thus formed. 
Chloride of 
ammonium. 
2NH4C1 + Ca2H0 = CaCl, + 2H.2() + 2NHS 
Hydrate of 
calcium. 
Chloride of 
calcium. 
Water. 
Ammonia 
gas. 
Ammonia gas is composed of one atom of nitrogen with three 
atoms of hydrogen ; its formula is NII3; two volumes of it contain 
one volume of nitrogen combined with three atoms or volumes of 
hydrogen. Its constituents have therefore in combining suffered AMMONIUM. 
91 
condensation to one half their normal bulk. Its conversion into 
hydrate of ammonium may be thus shown:— 
NIL, + 11,0 = NH4HO or AmTIO 
Ammonia 
gas. 
Water. 
Hydrate of ammonium 
(ammonia). 
Solutions of Ammonia, prepared by this process on a large scale 
and in suitable apparatus, are met with in pharmacy—the one (sp. 
gr. 0.900) containing 28 per cent., the other (sp. gr. 0.959), 10 per 
cent., by weight, of ammonia gas, NH3 {Aqua Ammonias Fortiar and 
Aqua Ammoniac, IT. S. P.). On the large scale, bottles are so ar- 
ranged in a series as to condense all the ammonia evolved during 
the operation. 
Acetate of Ammonium. 
Second Synthetical Reaction.—To acetic acid and water in 
a test-tube, add powdered commercial carbonate (acid carbon- 
ate and carbamate) of ammonium till effervescence ceases; the 
resulting liquid, made of prescribed strength, is the official 
solution of Acetate of Ammonium (NH4C2H302) (Liquor Am- 
monii Acetatis, U. S. P.), the old “ Spirit of Mindererus.” 
NH4HC03, NH4NH2C02 + 3HCjH,02 = 3NH4C2HA 
Acid carbonate and carbamate 
of ammonium. 
+ II.,0 + 2 CO, 
Acetic acid. 
Acetate of 
ammonium. 
Water. 
Carbonic acid gas. 
Commercial carbonate of ammonium is made by heating a mixture 
of chalk and sal-ammoniac ; chloride of calcium (CaCl2) is produced, 
ammonia gas (NH3) and water (1I20) escape, and the aminoniacal 
carbonate distils, or rather sublimes,* in cakes (Ammonii Carbonas, 
U. S. P.). The best form of apparatus to employ is a retort with a 
short wide neck and a cool receiver. On the large scale the retort 
is usually iron and the receiver earthenware or glass; on the small 
scale glass vessels are employed. The salt is purified by resublima- 
tion at a low temperature: 150° F. is said to be sufficient. 
This salt, the empirical formula of which is N3HuC205, is prob- 
ably a mixture of one molecule of acid carbonate or bicarbonate of 
ammonium (NII4HC03) and one of a salt termed carbamate of am- 
monium (NTI4NH2C02). The latter belongs to an important class 
of salts known as carbamates, but it is the only one of interest to the 
pharmacist. Cold water extracts it from the commercial carbonate 
of ammonium, leaving the acid carbonate of ammonium undissolved, 
if the amount of liquid used be very small. Alcohol extracts the 
carbamate, leaving the acid carbonate undissolved. In water, car- 
bamate soon changes into neutral carbonate of ammonium, 
Carbonates of Ammonium. 
* Sublimation (from sublimis, high). Vaporization of a solid sub- 
stance by heat, and its condensation on an upper and cooler part of 
the vessel or apparatus in which the operation is performed. 92 
THE METALLIC RADICALS. 
NII4NH2C02 + 1I20 = (NH4)2C03 or Am2C03; 
so that an aqueous solution of commercial carbonate of ammonium 
contains both acid carbonate and neutral carbonate of ammonium. 
If to such a solution some ordinary solution of ammonia be added, a 
solution of neutral carbonate of ammonium is obtained ; and this is 
the common reagent always found on the shelves of the analytical 
laboratory. 
AmIIC03 + AmHO = Am2C03 -f~ II20. 
Neutral carbonate of ammonium is the salt formed on adding strong 
solution of ammonia to the the commercial carbonate in preparing a 
pungent mixture for toilet smelling-bottles; but it is unstable, and 
on continued exposure to air is reduced to a mass of crystals of the 
acid carbonate or bicarbonate of ammonium. Bicarbonate of ammo- 
nium (NII4HC03) is also produced on passing carbonic acid gas into 
an aqueous solution of commercial carbonate. 
According to Divers, the sublimed product of the first distillation 
of chalk and sal-ammoniac is a mixture of carbamate and carbonate 
of ammonium, the latter losing some ammonia gas on redistillation, 
and carbamate with bicarbonate forming the resulting commercial 
salt. 
If carbonate of ammonium contain more than traces of empyreu- 
matic matters (derived primarily from the gas-liquors), an aqueous 
solution, with excess of sulphuric acid added, will decolorize a dilute 
solution of permanganate of potassium at once. 
Sal Volatile (Spiritus Ammonia! Aromaticus, U. S. P.) is a spirit- 
uous solution of ammonia (AmHO), neutral carbonate of ammonium 
(Am2C03), and the oils of lemon, lavender and pimenta. Fetid 
spirit of ammonia (Spiritus Ammonice Foetidus, B. P.) is an alco- 
holic solution of the volatile oil of asafoetida mixed with solution 
of ammonia. “ Solution of Carbonate of Ammonia,’- B. P., is formed 
by dissolving 1 part of the salt in 10 of water. Spiritus Ammonice, 
if. S. P., is an alcoholic solution of ammonia containing 10 per cent., 
by weight, of gas (NII3). 
Nitrate of Ammonium. 
Third Synthetical Reaction.—To some diluted nitric acid 
add carbonate of ammonium, until, after well stirring, a slight 
ammoniacal odor remains. The solution contains Nitrate of 
Ammonium (Ammonii Nitras, U. S. P.) 
NHJICOj, NH4NH2C02 + 3HN03 = 3NH4NO, + II,0 + 200 
Acid carbonate and carbamate 
of ammonium. 
Nitric 
acid. 
Nitrate of 
ammonium. 
Water. 
Carbonic 
acid gas. 
From a strong hot solution of nitrate of ammonium crystals may 
be obtained containing much water (NH4N03, 12H20). On heating 
these to about 310° F. the water escapes. The anhydrous salt re- 
maining (NII4N03) may be poured on to an iron plate. On further 
heating the powdered nitrate, it is resolved into nitrous oxide gas 
(the so-called laughing gas) and water. 93 
AMMONIUM. 
Nitrous oxide is thus prepared for use as an anaesthetic. When 
required for inhalation, it should be washed from any possible trace 
of acid or nitric oxide, by being passed through solution of potash, 
and through solution of ferrous sulphate. 
Nitrous oxide is slightly soluble in warm water, more so in cold. 
It supports combustion almost as well as oxygen. By pressure it 
may be liquefied to a colorless fluid, and by simultaneous cooling 
solidified. 
NH4N03 = N20 + 2H20. 
Citrate, Phosphate, and Benzoate of Ammonium. 
Fourth Synthetical Reaction. To solution of citric acid 
(H3C6H50: or II:JCi) add solution of ammonia (AmllO) until 
the well-stirred liquid smells faintly of ammonia; the product 
is Solution of Citrate of Ammonium (Am3Ci) (Liquor Ammo- 
vise Cdr at is, B. P:). 
Phosphate of Ammonium (Am,HP04) (Ammonii Phosphas, U. S. 
P ) and Benzoate of Ammonium (AmC7H502) (Ammonii Benzoas, 
L. S. P.) are also made by adding solution of ammonia to phos- 
phoric acid (1I3P04) and benzoic acid (HC7II502) respectively, evap- 
orating (keeping the ammonia in slight excess by adding more of its 
solution), and setting aside for crystals to form' The official Solu- 
tion of Acetate of Ammonium could he made in the same way ; hut, 
when prepared w'ith Carbonate of Ammonium, the liquid remains 
charged with carbonic acid, and has a less vapid flavor. 
IIsC,H507 + 3AmTT0 = Am3C,II50T + 3H,0 
Citric 
acid. 
Ammonia. 
Citrate of 
ammonium. 
Water. 
TI:iPO? + 2AmIIO = Am2HP04 + 2H,0 
Phosphoric 
acid. 
Ammonia. 
Phosphate of 
ammonium. 
Water. 
HCJI,02 + AniUO = AmC7II502 + II20 
Benzoic 
acid. 
Ammonia. 
Benzoate of 
ammonium. 
Water. 
Phosphate of ammonium occurs in transparent colorless prisms, 
soluble in water, insoluble in spirit; benzoate in crystalline plates, 
soluble in water and in spirit. 
Ammonii Indicium, U. S. P., may be made by decomposing the 
two bodies iodide of potassium and sulphate of ammonium, which 
give iodide of ammonium and sulphate of potassium; the latter 
salt is separated by adding alcohol to the cooled solution, when, by 
reason of its insolubility in alcohol, it crystallizes out, and the sep- 
arated solution of iodide of ammonium is then evaporated to dry- 
ness. It occurs usually in minute white crystalline cubes. 
Bromide of Ammonium (Ammonii Bromidum, U. S. P.) will he 
noticed in connection w ith Ilydrobromic Acid and other Bromides. 94 
THE METALLIC RADICALS. 
Fifth Synthetical Reaction.—To a nearly boiling solution of 1 
part of oxalic acid in about 8 of water add carbonate of am- 
monium until the liquid is neutral to test-paper (see follow- 
ing paragraph), filter while hot, and set aside for crystals 
((NH4)2CA)H20) to form. The mother-liquor is useful as a 
reagent in analysis; 1 of the salt in 20 of water constitutes 
“ Solution of Oxalate of Ammonium,” U. S. P. 
Oxalate of Ammonium. 
3H2C204 + 2N8HnCA = 3(NH4)2CA + 3C02 + 2H20 
Oxalic 
acid. 
Carbonate of 
ammonium. 
Oxalate of 
ammonium. 
Carbonic 
acid gas. 
Water. 
Neutralization.—Thus far, in reactions, the student has avoided 
excess of either acid matter on the one hand, or alkaline matter on 
the other, by the rough aid of taste, cessation of effervescence, pres- 
ence or absence of odor, etc. More delicate aid is afforded by test- 
papers. 
Test-papers.—Litmus is a blue vegetable pigment, prepared from 
various species of ltoccella lichen, exceedingly sensitive to the action 
of acids, which turn it red. When thus reddened, alkalies (potash, 
soda, and ammonia) and other soluble hydrates readily turn it blue. 
The student should here test for himself the delicacy of this action 
by experiments with paper soaked in solution of litmus and dipped 
into very dilute solutions of acids, acid salts (KHC4H406, e. </.), alka- 
lies, and such neutral salts as nitrate of potassium, sulphate of so- 
dium, or chloride of ammonium. 
Solution of Litmus (U. S. P.).—1 part of litmus is macerated for 
seven days in 10 parts of diluted alcohol, and the solution poured off 
from insoluble matter. 
Blue litmus paper (U. S. P.) is “ unsized white paper colored with 
solution of litmus.” lied litmus paper (U. S. P.) is “ unsized white 
paper colored with solution of litmus previously reddened by the 
smallest requisite quantity of sulphuric acid.” 
Turmeric paper (U. S. P.), similarly prepared from tincture of tur- 
meric (1 of turmeric root or rhizome to 6 of diluted alcohol, mace- 
rated for seven days), is occasionally useful as a test for alkalies, 
which turn its yellow to brown •, acids do not affect it. 
Sixth Synthetical Reaction.—Pass sulphuretted hydrogen 
gas (1I2S) through a small quantity of solution of ammonia in 
a test-tube, until a portion of the liquid no longer causes a 
white precipitate in solution of sulphate of magnesium (Epsom 
salt); the product is solution of sulphydrate (or sulphide) of 
ammonium (NH4HS), the “ Solution of Sulphide of Ammo- 
nium,” U. S. P., a most valuable chemical reagent, as will 
presently be apparent. 
Sulphydrate of Ammonium. 
NHJIO + H,S = NH4HS + H20. AMMONIUM. 
95 
“ Test-Solution of Sulphide of Ammonium,'' U. S. P., is made by 
passing the gas prepared in the apparatus described below into 3 
tluidounees of Water of Ammonia so long as the gas continues to 
be absorbed, then adding 2 more ounces of the ammonia, and pre- 
serving the solution in a wrell-stoppered bottle. 
Sulphuretted hydrogen is a compound of noxious odor; 
hence the above operation, and many others, described further 
on, in which this gas is indispensable, can only be performed 
in the open air, or in a fume-cupboard, a chamber so contrived 
that deleterious gases and vapors shall escape into a chimney 
in connection with the external air. In the above experiment, 
the small quantity of gas required can be made in a test-tube, 
after the manner of hydrogen itself. To two or three frag- 
ments of sulphide of iron (FeS), add water and then sulphuric 
acid; the gas is at once evolved, and may be conducted by a 
tube into the solution of Ammonia. Sulphate of iron remains 
dissolved in the water. 
FeS + H2S04 - H2S + FeS04. 
Crystals of sulphydrate of ammonium (X11,IIS) may be obtained 
on bringing ammonia gas (NH3) and sulphuretted hydrogen (fI2S) 
together at a low temperature. They are soluble in water without 
decomposition. 
Sulphuretted-Hydrogen Apparatus.—As no heat is necessary 
in making sulphuretted hydrogen, the test-tube of the fore- 
going operation may be advantageously replaced by a bottle, 
especially when larger quantities of the gas are required. 
In analytical operations the gas should be purified by passing 
it through water contained in a second bottle. 
The most convenient arrangement for experimental use is 
prepared as follows : Two common wide-mouthed bottles are 
selected, the one having a capacity of about half a pint, the 
other a quarter pint; the former may be called the generating- 
bottle, the latter the wash-bottle. Fit two corks to the bottles. 
Through each cork bore two holes by a round file or other 
instrument of such a size that glass tubing of about the diam- 
eter of a quill pen shall fit them tightly. Through one of the 
holes in the cork of the generating-bottle pass a funnel-tube, so 
that its extremity may nearly reach the bottom of the bottle. 
To the other hole adapt a piece of tubing, 6 inches long, and 
bent in the middle to a right angle. A similar “ elbow-tube ” 
is fitted to one of the holes in the cork of the wash-bottle, and 
another elbow-tube, one arm of which is long enough to reach 
to near the bottom of the wash-bottle, fitted to the other hole. 
Removing the corks, two or three ounces of water are now 96 
THE METALLIC RADICALS. 
poured into each bottle, an ounce or two of sulphide of iron put 
into the gcnerating-bottle, and the corks replaced. The elbow- 
tube of the generating-bottle is now attached by a short piece 
of India-rubber tubing to the long-armed elbow-tube of the 
Fig. 18. 
Sul pli uretted- Hydrogen Apparat us. 
wash-bottle, so that gas coming from the generator may pass 
through the water in the wash-bottle. The delivery-tube of 
the wash-bottle is then lengthened by attaching to it, by Incia- 
rubber tubing, another piece of glass tubing several inches in 
length. The apparatus is now ready for use. Strong sulphuric 
acid is poured down the funnel-tube in small quantities at a 
time, until brisk effervescence is established, and more added 
from time to time as the evolution of gas becomes slow. The 
gas passes through the tubes into the wash-bottle, where, as it 
bubbles up through the water, any trace of sulphuric acid, or 
other matter mechanically carried over, is arrested, and thence 
the gas flows out at the delivery-tube into any vessel or liquid 
that may be placed there to receive it. The generator must be 
occasionally dismounted and the sulphate of iron washed out. 
Luting (lutum, mud).—If the corks of the above apparatus are 
sound, and tube-holes well made, no escape of gas will occur. If 
rough corks have been employed, or the holes are not cylindrical, 
linseed-meal lute may be rubbed over the defective parts. The lute 
is prepared by mixing linseed-meal with water to the consistence of 
dough. A neat appearance may be given to the lute by gently rub- 
bing a well-wetted linger over its surface. 
(c) Reactions having Analytical Interest (Tests'). 
First Analytical Reaction■.—To a solution of any salt of am- 
monium (the chloride, for example) in a test-tube, add solution 
of caustic soda (or solution of potash, or a little slaked lime); AMMONIUM. 
97 
ammonia gas is at once evolved, recognized by its well-known 
odor. 
NII.Cl + NaHO = NH3 + ILO + NaCl. 
Though ammonium itself cannot be kept in the free state, its com- 
pounds are stable. Ammonia is easily expelled from these com- 
pounds by action of the stronger alkalies, caustic potash, soda, or 
lime. As a matter of exercise, the student should here draw out 
equations in which acetate (NII4C2II302), sulphate (Ain2S04), nitrate 
(NH4N08) or any other ammoniacal salt not already having the 
odor of ammonia, is supposed to be under examination ; also rep- 
resenting the use of the other hydrates, potash (KHO) or slaked lime 
(Ca2IIO). 
The odor of ammonia gas is perhaps the best means of rec- 
ognizing its presence; but the following tests are also occa- 
sionally useful. Into the test-tube in which the ammonia gas 
is evolved insert a glass rod moistened with hydrochloric acid 
(that is, with the solution of hydrochloric acid gas, conveniently 
termed hydrochloric acid, the Acidum Ilydrochloricum of the 
Pharmacopoeias) ; white fumes of chloride of ammonium will 
be produced. 
NH3 + HC1 = NH4C1. 
Hold a piece of moistened red litmus paper in a tube in which 
ammonia gas is present; the red color will be changed to blue. 
Second Analytical Reaction.—To a few drops of a solution 
of an ammonium salt add a drop or two of hydrochloric acid 
and a like small quantity of solution of perchloride of platinum 
(PtCl4) ; a yellow crystalline precipitate of the double chloride 
of platinum and ammonium (PtCl42NH4Cl) will be produced, 
similar in appearance to the corresponding salt of potassium, 
the remarks concerning which (p. 78) are equally applicable 
to the precipitate under notice. 
Third Analytical Reaction.—To a moderately strong solu- 
tion of an ammonium salt add a strong solution of tartaric 
acid, and shake or well stir the mixture; a white granular 
precipitate of acid tartrate of ammonium will be formed. 
For data from which to draw out an equation representing this 
action, see the remarks and formulae under the analogous salt of 
potassium (p. 77). 
Fourth Analytical Fact.—Evaporate a few drops of a solu- 
tion of an ammonium salt to dryness, or place a fragment of a 
salt in the solid state on a piece of platinum foil, and heat in 
a flame; the salt is readily volatilized. As already noticed, the 
salts of potassium and sodium are fixed under these cireum- 98 
THE METALLIC RADICALS. 
stances, a point of difference of which advantage will frequently 
be taken in analysis. A porcelain crucible may often be ad- 
vantageously substituted for platinum foil in experiments on 
volatilization. 
Salts of ammonium with the more complex acidulous radicals 
seldom volatilize unchanged when heated. The oxalate, when 
warmed, loses its water of crystallization, and at a higher tem- 
perature decomposes, yielding carbonic oxide, carbonic acid 
gas, ammonia gas, water (the three latter sometimes in combi- 
nation), and several organic substances. The phosphate yields 
more or less phosphoric acid as a residue. 
Fig. 19. 
Fig. 20. 
Fig. 21. 
A wire triangle may be used in supporting crucibles. It is made 
by twisting together each pair of ends of three (5 or 6 inch) crossed 
pieces of wire (Fig. 20). A piece of tobacco-pipe stem (about 2 
inches) is sometimes placed in the centre of each wire before twist- 
ing, the transference of any metallic matter to the sides of the cru- 
cible being thus prevented (Fig. 21). 
Triangular Supports for Crucibles. 
With regard to those experiments which are useful rather as means 
of detecting the presence of potassium, sodium, and ammonium, than 
as illustrating the preparation of salts, the student should proceed 
to apply them to certain solutions of any of the salts of potassium, 
sodium, and ammonium, with the view of ascertaining which metal 
is present; that is, proceed to practical analysis.* A little thought 
Practical Analysis. 
* Such solutions are prepared in educational laboratories by a tutor. 
They should, under other circumstances, be mixed by a friend, as it is 
not desirable to know previously what is contained in the substance 
about to be analyzed. 
The analysis of solutions containing only one salt serves to impress 
the memory with the characteristic tests for the various metals and 
other radicals, and familiarize the mind with chemical principles. AMMONIUM. 
99 
will enable him to apply these reactions in the most suitable order 
and to the best advantage for the contemplated purpose: but the 
following arrangements are perhaps as good as can be devised:— 
DIRECTIONS FOR APPLYING THE FOREGOING ANALYTICAL RE- 
ACTIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION OF 
A SALT OF ONE OF THE METALS, POTASSIUM, SODIUM, 
Ammonium. 
Add caustic soda to a small portion of the solution to be 
examined, and warm the mixture in a test-tube; the odor of 
ammonia gas at once reveals the presence of an ammonium 
salt. 
If ammonium be not present, apply the perchloride-of-plat- 
inum test to another portion of the liquid; a yellow precipitate 
proves the presence of potassium. 
(It will be observed that potassium can only be detected in 
the absence of ammonium, salts of the latter radical giving 
similar precipitates.) 
The flame-test is sufficient for the recognition of sodium. 
DIRECTIONS FOR APPLYING THE FOREGOING ANALYTICAL RE- 
ACTIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION OF 
SALTS OF ONE, TWO, OR ALL THREE OF THE ALKALI 
METALS. 
Commence by testing a small portion of the solution for an 
ammonium salt. If present, make a memorandum to that effect, 
and then proceed to get rid of the ammoniacal compound to 
make way for the detection of potassium: advantage is here 
taken of the volatility of ammonium salts and the fixity of those 
of potassium and sodium. Evaporate the original solution to 
dryness in a small basin, transfer the solid residue to a porce- 
lain crucible, and heat the latter to a low redness, or until dense 
white fumes (of ammoniacal salts) cease to escape. (See Fig. 
19.) This operation should be conducted in a fume-cupboard, 
to avoid contamination of the air of the apartment. When the 
crucible is cold, dissolve out the solid residue with a small 
quantity of hot water, and test the solution for potassium by 
Medical students seldom have time to go further than this. More 
thorough analytical and general chemical knowledge is only acquired 
by working on such mixtures of bodies as are met with in actual prac- 
tice, beginning with solutions which may contain any or all the mem- 
bers of a group. Hence in this Manual two Tables of short directions 
for analyzing are given under each group. Pharmaceutical students 
should follow the second Table. 100 
THE METALLIC RADICALS. 
the perchloride-of-platinum test, and for sodium by the flame- 
test. 
If ammonium is proved to be absent, the original solution 
may, of course, be at once tested for potassium and sodium. 
Flame-test.—The violet tint imparted to flame by potassium salts 
may be seen when masked by the intense yellow color due to sodium, 
if the flame be observed through a piece of dark-blue glass, a medium 
which absorbs the yellow rays of light. 
Note on Nomenclature.—The operations of evaporation and heat- 
ing to redness, or ignition, are frequently necessary in analysis, and 
are usually conducted in the above manner. If vegetable or animal 
matter be also present, carbon is set free, and ignition is accom- 
panied by carbonization; the material is said to char. When all 
carbonaceous matter is burnt off, the crucible being slightly inclined 
and its cover removed to facilitate combustion, and mineral matter, 
or ash, alone remains, the operation of incineration has been effected. 
Note on the Classification ofi Elements.—The compounds of potas- 
sium, sodium, and ammonium have many analogies. Their carbon- 
ates, phosphates, and other common salts are soluble in water. The 
atoms of the radicals themselves are univalent—that is, displace or 
are displaced by one atom of hydrogen. In fact, they constitute by 
their similarity in properties a distinct group or family. All the 
elements thus naturally fall into classes—a fact that should con- 
stantly be borne in mind, and evidence of which should always be 
sought. It would be impossible for the memory to retain the details 
of chemistry without a system of classification and leading princi- 
ples. Classification is also an important feature in the art as well 
as in the science of chemistry; for without it practical analysis 
could not be undertaken. The classification adopted in this volume 
is founded on the quantivalence of the elements and on their ana- 
lytical relations. 
QUESTIONS AND EXERCISES. 
117. Why are ammoniacal salts classed with those of potassium 
and sodium? 
118. Mention the sources of the ammonium salts. 
119. Describe the appearance and other characters of Chloride of 
Ammonium. 
120. Give the formula of Sulphate of Ammonium. 
121. Adduce evidence of the existence of ammonium. 
122. How are the official Waters of Ammonia prepared? Give 
diagrams. 
123. How is the official Solution of Acetate of Ammonium pre- 
pared ? 
124. What is the composition of commercial Carbonate of Ammo- 
nium ? 
125. Define sublimation. BARIUM. 
101 
126. What ammoniacal salts are contained in Spiritus Ammonias 
Aromaticus f 
127. Give diagrams or equations illustrating the formation of 
Citrate, Phosphate, and Benzoate of Ammonium? 
128. Give the formula of Oxalate of Ammonium. 
129. Show how Hydrate of Ammonium may be converted into 
Sulphydrate. 
130. Describe the preparation of Sulphuretted Hydrogen gas. 
131. Enumerate and explain the tests for ammonium. 
132. How is potassium detected in a solution in which ammonium 
has been found ? 
133. Give equations illustrating the action of hydrate of sodium 
on acetate of ammonium ; hydrate of potassium on sulphate of am- 
monium ; and hydrate of calcium on nitrate of ammonium. 
134. What are the effects of acids and alkalies on litmus and 
turmeric ? 
135. Describe the analysis of an aqueous liquid containing salts 
of potassium, sodium, and ammonium. 
136. What meanings are commonly assigned to the terms evapor- 
ation, ignition, carbonization, and incineration? 
137. Write a short article descriptive of the analogies of potas- 
sium, sodium, and ammonium, and their compounds. 
BARIUM, CALCIUM, MAGNESIUM. 
These three elements have many analogies. Their atoms are 
bivalent. 
Symbol Ba. Atomic weight 136.8. 
BARIUM. 
The analytical reactions only of this metal are of interest to the 
general student of pharmacy. The nitrate (Ba2N03) and chloride 
(BaCl2,2II.20) are the soluble salts in common use in analysis (“Test- 
Solution of Chloride of Barium,” 1 in 10 of water, U. S. P.); and 
these and others are made by dissolving the native carbonate 
(BaCO;j), the mineral witherite, in acids, or by heating the other 
common natural compound of barium, the sulphate, heavy white or 
heavy spar (BaSO,), with coal, which yields sulphide of barium (BaS), 
BaS04 + C4 = 4C0 + BaS, 
and dissolving the sulphide in appropriate acids. When the nitrate 
is strongly heated, it is decomposed, the oxide of barium or baryta 
(BaO) remaining. Baryta, on being moistened, assimilates the ele- 
ments of water with great avidity, and yields hydrate of barium 
(Ba2HO). The latter is tolerably soluble, giving baryta-water; 
and from this solution crystals of hydrate of barium are obtained 
on evaporation. 
The operations above described may all be performed in test-tubes 
and small porcelain crucibles heated by the gas-flame. Quantities of 
1 oz. to 1 lb. require a coke-furnace. 102 
THE METALLIC RADICALS. 
Peroxide of barium, (Ba02) is formed on passing air over baryta 
heated to low redness. By the action of dilute hydrochloric acid it 
yields solution of peroxide of hydrogen (II20,2), the old oxygenated 
water. 
Quantivalence.—The atom of barium is bivalent, Ba//. 
Reactions having Analytical Interest (Tests). 
First Analytical Reaction.—To the aqueous solution of any 
soluble salt of barium (nitrate or chloride, for example) add 
dilute sulphuric acid ; a white precipitate is obtained. Set the 
test-tube aside for two or three minutes, and when some of the 
precipitate has fallen to the bottom pour away the supernatant 
liquid; wash the precipitate by adding water, shaking, setting 
aside, and again decanting; then add strong nitric acid, and 
boil; the precipitate is insoluble. 
The production of a white precipitate by sulphuric acid, insoluble 
even in hot nitric acid, is highly characteristic of barium. The name 
of this precipitate is sulphate of barium; its formula is BaS04. 
Antidotes.—In cases of poisoning by soluble barium salts, obvious 
antidotes would be solutions of alum or of any sulphates, such as 
those of magnesium and sodium (Epsom salt, Glauber’s salt). 
Second Analytical Reaction.—To a barium solution add 
solution of the yellow chromate of potassium (K2Cr04) ; a pale 
yellow precipitate (BaCr04) falls. Add acetic acid to a por- 
tion of the chromate of barium ; it is insoluble. Add hydro- 
chloric or nitric acid to another portion; it is soluble. 
“ Neutral Chromate.”—The red chromate (or bichromate) of po- 
tassium (K2Cr04,Cr03) must not be used in this reaction, or the 
barium will be only imperfectly precipitated ; for the red salt gives 
rise to the formation of free acid, in which chromate of barium is to 
some extent soluble:— 
K2Cr04,Cr03 + 2BaCl2 + II20 = 2BaCr04 + 2KC1 + 2HC1. 
Yellow chromate is obtained on adding carbonate of potassium, in 
small quantities at a time, to a hot solution of the red chromate until 
effervescence ceases; a little more red chromate is then added to en- 
sure decomposition of any slight excess of carbonate of potassium. 
K2Cr04,Cr03 + K2C03 = 2K2Cr04 + C02. 
For analytical purposes, solution of a neutral chromate is still 
more readily prepared by simply adding solution of ammonia to 
solution of red chromate of potassium, until the liquid turns yel- 
low, and, after stirring, smells of ammonia. 
K2Cr04,Cr03 + 2NH4HO = 2KNH4Cr04 + II20. 
Other Analytical Reactions.—To a barium solution add a 
soluble carbonate (carbonate of ammonium (Am2C03) will 
generally be rather more useful than others); a white precipi- CALCIUM. 
103 
tate of carbonate of barium (BaC03) results. To more of 
the solution add an alkaline phosphate or arseniate (phosphate 
of sodium (Na2HP04) is the most common of these chemically 
analogous salts, but phosphate of ammonium (Am2HP04) or 
arseniate (Am,HAs04) will subsequently have the preference); 
white phosphate of barium (BaHP04), insoluble in pure water, 
hut slightly soluble in aqueous solutions of some salts, or 
arseniate of barium (BaHAs04), both soluble even in acetic 
and other weak acids, are precipitated. To another portion 
add oxalate of ammonium (Am2C204); white oxalate of barium 
(BaC204) is precipitated, soluble in the diluted mineral acids, 
and sparingly so in acetic acid. The silico-fluoride of barium 
(BaSiP6) is insoluble, and bills readily if an equal volume of 
spirit of wine be added to the solution under examination after 
the addition of hydrofluosilicic acid (H2SiF6). Barium salts, 
moistened with hydrochloric acid, impart a greenish color to 
flame. 
Mem.—Good practice will be found in writing out equations de- 
scriptive of each of the foregoing reactions. 
QUESTIONS AND EXERCISES. 
138. What is the quantivalence of barium ? 
139. Write down the formulae of oxide, hydrate, chloride, nitrate, 
carbonate, and sulphate of barium; and state how these salts are 
prepared. 
140. Describe the preparation of peroxide of hydrogen. 
141. Which of the tests for barium are most characteristic? Give 
an equation of the reactions. 
142. Name the antidote in cases of poisoning by soluble barium 
salts, and explain its action. 
Symbol Ca. Atomic weight 40. 
CALCIUM. 
Calcium compounds form a large proportion of the crust of our 
earth. Carbonate of calcium is met with as chalk, marble, lime- 
stone, calc-spar, etc.; the sulphate, as gypsum or plaster of Paris 
(native sulphate of calcium—CaS04,2II20—deprived of water by 
heat), and alabaster; the silicate in many minerals; the fluoride of 
calcium as fluor-spar. The phosphate is also a common mineral. 
The element itself is only isolated with great difficulty. The atom 
of calcium is bivalent, Ca". 
Reactions having Synthetical Interest. 
Chloride of Calcium. 
First Synthetical Reaction.—To some hydrochloric acid add 
carbonate of calcium (chalk, or, the purer form, white marble) 104 
THE METALLIC RADICALS. 
(CaC03) until effervescence ceases, filter; solution of chloride 
of calcium (CaCl2), the most common soluble salt of calcium, 
is formed. 
Carbonate of 
calcium. 
CaC03 + 2HC1 = CaCl2 + H20 + C02 
Hydrochloric 
acid. 
Chloride of 
calcium. 
Water. 
Carbonic 
acid gas. 
This solution contains carbonic acid, and will give a precipitate 
of carbonate of calcium on the addition of lime-water. It may be 
obtained quite neutral by well boiling before filtering off the excess 
of marble. It is a serviceable test-liquid in analytical operations. 
Solution of chloride of calcium evaporated to a syrupy consist- 
ence readily yields crystals (CaCl2,6II20). These are extremely 
deliquescent. The solution, evaporated to dryness, and the white 
residue strongly heated, gives solid anhydrous chloride of calcium 
in a porous form. The resulting agglutinated lumps (Calcii Chlori- 
dum, U. S. P.) are much used for drying gases, and for freeing cer- 
tain liquids from water. The salt is soluble in alcohol. One part 
of the crystals in ten of water constitutes a useful test-liquid, “Test- 
solution of Chloride of Calcium,” U. S. P. 
Mem.—The practical student has already met with solution of 
chloride of calcium as a by-product or secondary product in the 
preparation of carbonic acid gas. 
Marble often contains ferrous carbonate (FeC03), which in 
the above process becomes converted into ferrous chloride, 
rendering the chloride of calcium impure:— 
FeCO:) + 2II Cl - FeCl2 + H20 + C02 
Ferrous 
carbonate. 
Hydrochloric 
acid. 
Ferrous 
chloride. 
Water. 
Carbonic 
acid gas. 
If absolutely pure chloride of calcium be required, a few 
drops of the solution should be poured into a test-tube or test- 
glass, diluted with water, and examined for iron (by adding 
sulphydrate of ammonium, which gives a black precipitate with 
salts of iron), and, if the latter is present, hypochlorite of cal- 
cium (in the form of chlorinated lime) and slaked lime should 
be added to the remaining bulk of the liquid, and the whole 
boiled for a few minutes, whereby iron (as ferric hydrate) is 
thus precipitated ; on filtering, a pure solution of chloride of 
calcium is obtained :— 
4FeCl2 + Ca2C10 + 4CaH202 + 2H,,0 
Ferrous 
chloride. 
Hypochlorite 
of calcium. 
Hydrate of 
calcium. 
Water. 
= 2(Fe26HO) + 5CaCl, 
Ferric 
hydrate. 
Chloride 
of calcium. 
This is the official process, and may be imitated on the small CALCIUM. 
105 
scale after adding a minute piece of iron to a fragment of the 
marble before disolving in acid. 
'l he names, formulae, and reactions of these compounds of iron 
will be best understood when that metal comes under treatment. 
Oxide of Calcium (Quick Lime) 
Second Synthetical Reaction.—Place a small piece of chalk 
in a strong grate-fire or furnace and heat until a trial fragment, 
chipped off from time to time and cooled, no longer effervesces 
on the addition of acid; caustic lime, CaO (Calx, PI S. 
remains. 
CaC03 = CaO + C02 
Carbonate of 
calcium (chalk). 
Oxide of 
calcium (lime). 
Carbonic 
acid gas. 
An/e.—Etymologically considered, this action is analytical (avalvu, 
analuo, l resolve) and not synthetical (avvdemc, sunthesis, a putting 
together); but conventionally it is synthetical, and not analytical; 
for in this, the usual sense, and the sense in which the words are 
used throughout this book, synthesis is the application of chemical 
action with the view of producing something, analysis the applica- 
tion of chemical action with the view of finding out the composition 
of a substance. In the etymological view of the matter, there is 
scarcely an operation performed either by the analyst or by the 
manufacturer but includes both analysis and synthesis—that is, 
includes interchange, or metathesis. 
Lime-kilns.—On the large scale the above operation is carried on 
in what are termed lime-kilns (Kiln, Saxon, cyln, from cylene, a 
furnace). 
Hydrate of Calcium (Slaked Lime). 
Slaked Lime.—When cold, add to the lime about half its 
weight of water, and notice the evolution of steam and other 
evidence of strong action ; the product is slaked lime or hydrate 
of calcium (Ca21IO), with whatever slight natirral impurities 
the lime might contain. The slaking of hard or “stony” lime 
may be accelerated by using hot water. 
CaO + TI,0 = Ca2HO 
Lime-water.—Place the hydrate of calcium (tvashed with a 
little water to remove traces of soluble salts) in about a 
hundred times its weight of water; in a short time a satu- 
rated solution, known as lime-water (Liquor Calcis, U. S. P.), 
results. It contains about 0.15 per cent of slaked lime, or 
about 16 grains of hydrate of calcium (Ca2HO), equivalent 
to about 11 or 12 grains of lime (CaO), in one (Imperial) pint 
Lime. 
Water 
Hydrate of calcium 
(slaked lime). 106 
THE METALLIC RADICALS. 
at 60° F., at higher temperatures less is dissolved. Sp. gr. 
1.0015. 
Strong Solution of Lime.—Slaked lime is much more soluble in 
aqueous solution of sugar than in pure water. The Syrupus Calais, 
U. S. P., is such a solution, containing 5 parts of lime and 30 of 
sugar in 100 parts, by weight, of fluid. 
Solutions of hydrate of calcium absorb carbonic acid gas on ex- 
posure to air, a semi-crystalline precipitate of carbonate being de- 
posited. When the saccharated solution is heated, there is precipi- 
tated a compound consisting of three molecules of lime with one of 
sugar. 
Carbonate of Calcium. 
Third Synthetical Reaction.—To a solution of chloride of 
calcium add excess of carbonate of sodium, or about 5 parts 
of dry chloride to 13 of carbonate ; a white precipitate of car- 
bonate of calcium (Calcii Gtrbonas Prsecipitatus, U. S. P.) 
(CaC03) results. If the solutions of the salts be made hot 
before admixture, and the whole set aside for a short time, the 
particles aggregate to a greater extent than when cold water 
is used, and the product is finely granular or slightly crystal- 
line. 
Chloride of 
calcium. 
CaCl2 + Na,CO, = CaC08 + 2NaCl 
Carbonate of 
sodium. 
Carbonate of 
calcium. 
Chloride of 
sodium. 
Collect and purify this Precipitated Chalk by pouring the 
mixture into a paper cone supported by a funnel, and, when 
the liquid has passed through the filter, pour water over the 
precipitate three or four times until the whole of the chloride 
of sodium is washed away. This operation is termed washing 
a precipitate. When dried by aid of a water-bath (p. 109) or 
other means, the precipitate is fit for use. 
Filtering-paper, or bibulous-paper (from bibo, to drink), is simply 
good unsized paper made from the best white rags—white blotting- 
paper, in fact, of unusually good quality. Students’ or analysts’ 
Fig. 22. 
Const ruction of Paper Filters. 
filters, on which to collect precipitates, are circular pieces (a) of this 
paper, from three to six inches in diameter, twice folded (ft, c), and 
then opened out so as to form a hollow cone (cl). Square pieces are CALCIUM. 
107 
rounded by scissors after twice folding. The cone is supported by 
a glass or earthenware funnel. 
Filters should always be cut round so as to form a cone. If the 
square piece of paper is folded and used without being so cut or 
trimmed, an ugly angular filter results, from which it is difficult to 
wash all “ mother-liquor ” (the solution of chloride of sodium is the 
“ mother-liquor ” in the previous reaction). If a spirituous or other 
volatile liquor is being passed through such an angular filter, much 
of the liquid will also be wasted by evaporation from the unneces- 
sarily large surface exposed. 
Paper filters of large size are apt to break at the point of the cone. 
This may be prevented, and the rate of filtration be much accelerated, 
by supporting the paper cone in a cone of muslin. 
Washing-bottle.—Precipitates are best washed by a fine jet of 
water directed on to the different parts of the filter. A common 
narrow-necked bottle of about half-pint capacity (Fig. 23) is fitted 
with a cork; two holes are bored through the cork, the one for a 
glass tube reaching to the bottom of the bottle within, and exter- 
nally bent to a slightly acute angle, the other for a tube bent to a 
slightly obtuse angle, the inner arm terminating just within the 
bottle. The outer arms may be about 3 inches in length. The ex- 
tremity of the outer arm continuous with the long tube should be 
previously drawn out to a fine capillary opening by holding the 
original tube, before cutting, in a flame, and, when soft, slowly pull- 
ing the halves away from each other until the heated portion is re- 
duced to the thinness of a knitting-needle. The tube is now cut at 
the thin part by a file, and the sharp edges rounded off by placing in 
Fig 23. 
Fig. 24. 
a flame for a second or two. The outer extremity of the shorter tube 
should also be made smooth in the flame. The apparatus being put 
together, and the bottle nearly filled with water, air, blown through 
the short tube by the lungs, forces water out in a fine stream at the 
capillary orifice. 
For a hot-water washing flash (Fig. 24) the tubes and cork are 
fitted to a flask which may be heated. A strip of leather tied 
round the neck will protect the fingers. 
Decantation.—Precipitates may also be washed by allowing them 
to settle, pouring off the supernatant liquid (Fig. 25), agitating with 
"Washing-bottles. 108 
THE METALLIC RADICALS. 
water, again allowing to settle, and so on. This is washing by de- 
cantation (de, from, canthus, an edge). If a stream of liquid flow- 
ing from a basin or other vessel exhibits any tendency to run down 
the outer side of the vessel, it should be guided by a glass rod placed 
against the point whence the stream emerges (Fig. 26). 
Fig. 25. 
Fig. 26. 
Fig. 27. 
Decantation. 
Decantation. 
Siphon in action. 
If the vessel be too large to handle with convenience, the wash- 
water may be drawn off by a siphon, as shown in miniature in Fig. 
27. A siphon is a tube of glass, metal, gutta-percha, or India-rubber 
bent into the form of a Y or U, filled with water, and inverted ; one 
end immersed in the wash-water, and the other allowed to hang over 
the side of the vessel. So long as the outer orifice of the instrument 
is below the level of any liquid in the vessel, so long will'that liquid 
flow from within outwards.* 
Prepared carbonate of calcium (Greta Prceparata, U. S. P.) is 
merely washed chalk or whiting, only that in Pharmacy fashion 
demands that the chalk be in little conical lumps, about the size of 
thimbles, instead of the larger rolls characteristic of “ whiting.” 
Wet whiting pushed, portion by portion, through a funnel, and each 
separately dried, gives the conventional Greta Prceparata. Its powder 
is amorphous. 
Testa Prceparata is powdered oyster-shell, similarly treated. It is 
an inferior kind of prepared chalk. 
* The nature of the action of a siphon is simple. The column of water 
in the outer limb is longer, and therefore heavier than the column of 
similar area in the inner limb. (The length of the inner limb must 
be reckoned from the surface of the liquid, the portion below the sur- 
face playing no part in the operation.) Being heavier, it naturally 
falls by gravitation, the liquor in the shorter limb instantly following, 
because pressed upwards by the air. The air, be it observed, exerts a 
similar amount of pressure on the liquid in the outer limb: in short, 
atmospheric pressure causes the retention of liquid in the instrument, 
while gravitation determines the direction of the flow. CALCIUM. 
109 
Fourth Synthetical Reaction.—Digest bone-ash (bones burnt 
in an open crucible with free access of air till all animal and 
carbonaceous matter has been removed—impure phosphate of 
calcium (Os Ustum, B. P.)) with nearly twice its weight of 
hydrochloric acid (diluted with tln’ee or four times its bulk of 
water), in a test-tube or larger vessel; the phosphate is dis- 
solved. 
Phosphate of Calcium. 
Ca32P04 -} 4 PI Cl = CaII42P04 + 2CaCl2 
Phosphate of 
calcium (impure). 
Hydrochloric 
acid. 
Acid phosphate 
of calcium. 
Chloride of 
calcium. 
Dilute with water, filter, boil, and when cold add excess of 
solution of ammonia; the phosphate of calcium, now pure 
( Calcii Phosphas Prsecipitatus, U. S. P.), is reprecipitated as a 
light white amorphous powder. After well washing, the pre- 
cipitate should be dried over a water-bath (see below), or at a 
temperature not exceeding 212°, to prevent undue aggregation 
of the particles. 
CaH42POt + 2CaCl, + 4AmH0 = Ca32P04 + 4A*nCl 
Acid phosphate 
of calcium. 
Chloride 
of calcium. 
Ammonia. 
Phosphate 
of calcium 
(pure). 
Chloride of 
ammonium. 
+ 411,0 
Water. 
Bone-ash or bone-earth contains small quantities of carbonate 
and sulphide of calcium. These are decomposed in the above 
process by the acid, chloride of calcium being formed ; on boil- 
ing the mixture, carbonic acid gas and sulphuretted hydrogen 
gas are evolved. Any carbonaceous or siliceous matter, etc. 
is removed by filtration. In bones the phosphate of calcium is 
always accompanied by a small quantity of an allied substance, 
phosphate of magnesium ; a trace of fluoride of calcium (CaF2) 
is also present. 
A Water-bath for the evaporation of liquids or for drying 
moist solids at temperatures below 212° F. is an iron, tin, or 
earthenware pan, the mouth of which can be narrowed by iron 
or tin diaphragms of various sizes, and having orifices adapted 
to the diameters of evaporating dishes or plates. In the British 
Pharmacopoeia, “ when a water-bath is directed to be used, it 
is to be understood that this term refers to an apparatus by 
means of which water or its vapor, at a temperature not ex- 
ceeding 212°, is applied to the outer surface of a vessel con- 
taining the substance to be heated, which substance may thus 
be subjected to a heat near to, but necessarily below, that of 
212°. In the steam-bath the vapor of water at a temperature TI1E METALLIC RADICALS. 
above 212°, but not exceeding 230°, is similarly applied.” 
Evaporation in vacuo is performed by simply placing the vessel 
of liquid over or by the side of a small reservoir of strong sul- 
phuric acid, or other absorbent of moisture, on the plate of an 
air-pump, covering with a capacious glass hood or “ receiver,” 
and exhausting. 
Bone-black, or Animal Charcoal (Carbo Animalis, U. S. P.), 
is the residue obtained on subjecting dried bones to a red heat 
without access of air. The operation may be imitated by heat- 
ing a few fragments of bone in a covered porcelain crucible in 
a fume-chamber until smoke and vapor cease to be evolved. 
Purified Animal Charcoal ( Carbo Animalis Purificatns, U.S. P.) 
is obtained by digesting animal charcoal (2 parts) in hydro- 
chloric acid (3 parts) and water (30 parts) in a warm place for 
a day or so, filtering, thoroughly washing, drying over a water- 
bath, and igniting the product in a closely covered crucible. 
The reaction is the same as that just described; that is to say, 
the acid removes the phosphate of calcium from the carbon of 
animal charcoal by forming soluble acid phosphate and chloride 
of calcium. 
Wood Charcoal (Carbo Ligni, U. S. P.) is wood similarly 
ignited without access of air. 
Decolorizing Power of Animal Charcoal.—Animal charcoal, 
in small fragments, is the material employed in decolorizing 
solutions of common brown sugar with the view of producing 
white lump sugar. Its power and the nearly equal power of 
an equivalent quantity of the purified variety may be demon- 
strated on solution of litmus or logwood. 
Syrvpus Calcii Lacto-phosphatis, U. S. P., is a flavored solu- 
tion of precipitated phosphate of calcium in lactic acid. 
Phosphate of Sodium.—Phosphate of calcium is converted 
into phosphate of sodium (SodiiPhosphas, U. S. P.) (Na2HP04, 
12EPO) as follows : Mix, in a mortar, 3 ounces of ground bone- 
earth with one fluidounce of sulphuric acid; set aside for 
twenty-four hours to promote reaction ; mix in about 3 ounces 
of water, and put in a warm place for two days, a little water 
being added to make up for that lost by evaporation; stir in 
another 3 ounces of water, warm the whole for a short time, 
filter, and wash the residual sulphate of calcium on the filter 
to remove adhering acid phosphate of calcium ; concentrate the 
filtrate (the liquid portion), which is a solution of acid phos- 
phate of calcium, to about 3 ounces, filter again, if necessary, 
add solution of (about ounces of crystals of) carbonate of 
sodium to the hot filtrate until a precipitate (a phosphate of CALCIUM. 
111 
calcium, CalIP04) ceases to form, and the fluid is faintly alka- 
line ; Alter, evaporate, and set aside to crystallize. 
Phosphate of sodium occurs “ in transparent colorless rhom- 
bic prisms, terminated by four converging planes, efflorescent, 
tasting like common salt.” One part to ten of water constitutes 
“ Solution of Phosphate of Soda,” B. P. This is an official as 
well as the ordinary process. The following equations show 
the two decompositions which occur during the operation:— 
Ca32P04 + 2IT2S04 = CaH42P04 + 2CaS04 
Phosphate 
of calcium. 
Sulphuric 
acid. 
Acid phosphate 
of calcium. 
Sulphate of 
calcium. 
Cal 1,21 A + Na2C0:! = Na2HP04 + H20 
Acid phosphate 
of calcium. 
Carbonate 
of sodium. 
Phosphate of 
sodium. 
Water 
+ C02 + CaHP04 
Carbonic 
acid gas. 
Phosphate 
of calcium. 
Ordinary phosphate of sodium (Na2lIP04,12H20) effloresces 
rapidly in the air until nearly half its water has escaped, when 
it has a permanent composition represented by the formula 
Na2HP04,7H20. Phosphate of sodium has an alkaline reac- 
tion ; neutralization by acid results in the removal of half its 
sodium and formation of the salt NaH2P04,H2G. 
Fifth Synthetical Reaction.—Pass chlorine, generated as 
already described, into damp slaked lime contained in a piece 
of wide tubing, open at the opposite end to that in which the 
delivery-tube is fixed. (A test-tube, the bottom of which has 
been accidentally broken, is very convenient for such opera- 
tions.) The product is ordinary bleaching-powder, a compound 
of hypochlorite and chloride of calcium, commonly called chlo- 
ride of lime (Calx Chlorata, U. S. P.). 
Hypochlorite of Calcium. 
Black oxide 
of manganese. 
MrA + 411 Cl = MnCl2 + 211,0 + Cl2 
Hydrochloric 
acid. 
Chloride of 
manganese. 
Water, 
Chlorine. 
2CaH202 + 2C1, =• 2H20 + CaCIA, CaCl2 
Hydrate of 
calcium. 
Chlorine. 
Water. 
Hypochlorite of 
of calcium. 
Chloride 
of calcium 
Chlorinated lime, exposed to air and moisture, as in disinfecting 
the air of sick-rooms, slowly yields hypochlorous acid (HCIO). Free 
hypochlorous acid soon breaks up into water, chloric acid (11C103), 
and free chlorine. Chloric acid is also unstable, decomposing into 
oxygen, water, chlorine, and perchloric acid (HC104). The small 
quantity of hypochlorous acid diffused through an apartment when 
bleaching-powder is exposed thus, yields fourteen-fifteenths of its 112 
THE METALLIC RADICALS. 
chlorine in the form of chlorine gas—one of the most efficient of 
known disinfectants. 
Constitution of Bleaching-powder.—Treated with alcohol, 
bleaching-powder does not yield its chloride of calcium to the 
solvent, hence the powder is not a mere mixture of chloride 
and hypochlorite of calcium : water, also, does not dissolve out 
first one salt, and then the other, but both together, in the 
molecular proportions of the above formula. On the other 
hand, when the aqueous solution is cooled, or evaporated in 
vacuo, crystals are obtained which Kingzett has shown to be 
nearly pure hypochlorite of calcium, the solution containing 
chloride of calcium. While the former fact indicates that the 
powder is a compound, and not a mere mixture, the latter in- 
dicates that it is a feeble compound ; an adhesion of molecules 
of hypochlorite and chloride, as shown in the equation, rather 
than any more intimate or closer combination of atoms. If 
it be regarded as a single rather- than a double salt, then the 
( Cl 
following formula may be employed, Ca j 
Bleaching-Kquor.—Digest chlorinated lime in water, in which 
the bleaching compound is soluble, filter from the undissolved 
lime, and test the bleaching powers of the clear liquid by add- 
ing a few drops to a decoction of logwood slightly acidulated. 
One pound of this bleaching-powder, shaken several times 
during three hours with 1 gallon of water, forms Solution of 
Chlorinated Lime (Liquor Calcis Chlorate-, B. P.). 
Sixth Synthetical Reaction.—Heat a mixture of 10 parts of 
powdered lime and 9 of sulphur in a crucible having a luted 
cover for an hour. The product, when cold, rubbed to powder, 
constitutes Sulphurated Lime (Calx Sulphur at a., IT. S. P.). 
It should contain not less than 36 per cent, of sulphide of 
calcium (CaS) ; the remainder is sulphate, with, probably, sul- 
phite and hyposulphite of calcium. 
Gummate of Calcium is the only official calcium salt that 
remains to be noticed. This compound is, in short, arabin, 
the ordinary Gum Acacia, or Gum Arabic (Acacia, U. S. P.), 
a substance too well known to need description. A solution 
of gum arabic in water (Mwilago Acacise, U. S. P.) yields a 
tvhite precipitate of oxalate of calcium on the addition of solu- 
tion of oxalate of ammonium. Or a piece of gum burnt to an 
ash in a porcelain crucible yields a calcareous residue, which, 
dissolved in dilute acids, affords characteristic reactions with 
Gummate of Calcium. CALCIUM. 
113 
any of the following analytical reagents for calcium. In some 
specimens of gum arabic a portion of the calcium is displaced 
by an equivalent quantity of potassium or magnesium. The 
gummic radical may be precipitated as opaque gelatinous gum- 
mate of lead by the addition of solution of oxyacetate of lead 
(Liquor Rlumfi Subacetatis, U. S. P.) to an aqueous solution 
of gum. These statements may be experimentally verified by 
the practical student. 
Tragacanth (Tragacantha, U. S. P.) is a mixture of soluble arabi- 
noid gum and a variety of calcium gum insoluble in water, termed 
bassorin. With water a gelatinous mucilage is formed (Mucilago 
Tragacanthce, U. S. P., contains 6 parts of tragacanth, 18 of gly- 
cerin, and 76 of water). 
Reactions having Analytical Interest (Tests) 
First Analytical Reaction.—Add sulphuric acid, very highly 
diluted, to a calcium solution contained in a test-tube or small 
test-glass; sulphate of calcium (CaS04,2H20) is formed, but 
is not precipitated, it being, unlike sulphate of barium, slightly 
soluble in water. 
Solution of Sulphate of Calcium.—A quarter of an ounce of that 
(dried) form of sulphate of calcium known as plaster of Paris (CaS04) 
digested in one pint of water for a short time, with occasional shak- 
ing, and the mixture filtered, yields the official test-liquid termed 
“ Solution of Sulphate of Lime,” B. P. About 40U parts of the 
solution contain 1 of calcium. 
Second Analytical Reaction.—Add yellow chromate of potas- 
sium (K,Cr04), or other neutral chromate (KAmCr04), to a 
calcium solution slightly acidified with acetic acid; chromate 
of calcium (CaCr04) is probably formed, but it is not precipi- 
tated. Barium is precipitated by the chromic radical. 
These two negative reactions are most valuable in analysis, as 
every precipitant of calcium is also a precipitant of barium ; but 
the above two reagents are precipitants of barium only. lienee 
calcium, which when alone can be readily detected by the following 
reactions, cannot by any reaction be detected in the presence of 
barium. But by the sulphuric or chromic test barium is easily 
removed, and then either of the following reagents will throw down 
the calcium. 
Ollier Analytical Reactions.—Add carbonate of ammonium, 
phosphate of sodium, arseniate of ammonium, and oxalate of 
ammonium to calcium solutions as described under the ana- 
lytical reactions of barium, and write out descriptive equations. 
The precipitates correspond in appearance to those of barium ; 114 
TIIE METALLIC RADICALS. 
their constitution is also similar, hence their correct formulae 
can easily be deduced. Of these precipitants oxalate of am- 
monium is that most commonly used as a reagent for calcium 
salts, barium being absent. The oxalate of calcium is insoluble 
in acetic, but soluble in hydrochloric or nitric acid. Cal- 
cium compounds impart a reddish color to the flame. 
143. Enumerate some of the common neutral compounds of cal- 
cium. 
144. Explain, by an equation, the action of hydrochloric acid on 
marble. What official compounds result? 
145. Why is chloride of calcium used as a desiccator for gases? 
146. How would you purify Chloride of Calcium which has been 
made from ferruginous marble ? Give diagrams. 
147. Write a few lines on the chemistry of the lime-kiln. 
148. In what sense is the conversion of chalk into lime an analyt- 
ical action? 
149. What occurs when lime is “slaked”? 
150. To what extent is lime soluble in water? to what in syrup? 
151. Describe the preparation of the official Precipitate of Carbo- 
nate of Calcium ; in what does it differ from Prepared Chalk ? 
152. In what does filtering-paper differ from other kinds of paper? 
153. Explain the construction of “a washing-bottle” for cleans- 
ing precipitates by water. 
154. Describe decantation. 
155. Describe the construction and manner of employment of a 
siphon. 
156. Explain the mode of action of a siphon. 
157. What is the difference between Bone, Bone-earth, and Pre- 
cipitated Phosphate of Calcium ? 
158. How is “Bone-earth” purified for use in medicine? 
159. Explain the action of hydrochloric acid on Animal Char- 
coal in the conversion of Carbo Animalis into Carbo Animalis 
Purificatus. 
160. What is the chemical difference between Carbo Animalis 
and Carbo Ligni ? 
161. Give equations showing the conversion of Phosphate of Cal- 
cium into Phosphate of Sodium. 
162. Write a short article on the manufacture, composition, and 
uses of “ bleaching-powder.” 
163. How may calcium be detected in Gum Arabic? 
164. State the chemical nature of Tragacanth. 
165. To what extent is sulphate of calcium soluble in water? 
166. Can calcium be precipitated from an aqueous solution con- 
taining barium ? 
167. Barium being absent, what reagents may be used for the 
detection of calcium? Which is the chief test? 
QUESTIONS AND EXERCISES. MAGNESIUM. 
115 
MAGNESIUM. 
Source.—Magnesium is abundant in nature in the form of magne- 
sian or mountain limestone, or dolomite, a double carbonate of mag- 
nesium and calcium in common use as a building-stone (e. g., the 
Houses of Parliament and the School of Mines in London), and 
magnesite, a tolerably pure carbonate of magnesium, though too 
“ stony ” for direct use in medicine, even if very finely powdered. 
Chloride of magnesium and sulphate of magnesium (Epsom salt) 
also occur in sea-water and in the water of many springs. A mono- 
hydrous sulphate (MgS04,H20) termed kieserit occurs near Stass- 
furt in Prussia. Metallic magnesium may be obtained from the 
chloride by the action of sodium. It burns readily in the air, 
emitting a dazzling light, due to the white heat to which the result- 
ing particles of magnesia (MgO) are exposed. The chloride em- 
ployed as a source of the metal is obtained by dissolving the car- 
bonate in hydrochloric acid, adding some chloride of ammonium, 
evaporating to dryness, heating the residue in a flask (on the small 
scale a large test-tube or Florence flask) until the chloride of am- 
monium is all volatilized and the chloride of magnesium remains a* 
a clear fused liquid. The latter is poured on to a clean earthenware 
slab. The chloride of ammonium prevents reaction between chlo- 
ride of magnesium and water in the last stages of the operation and 
consequent formation of oxide (or oxychloride) of magnesium and 
hydrochloric acid gas. 
Quantivalence.—The atom of magnesium is bivalent, Mg//. 
Symbol Mg. Atomic weight 24. 
Reactions having Synthetical Interest. 
Sulphate of Magnesium. 
First Synthetical Reaction.—To a few drops of sulphuric 
acid and a little water in a test-tube, made hot (or to larger 
quantities in larger vessels), add powdered native carbonate of 
magnesium, magnesite, Mg003, until effervescence ceases, sub- 
sequently boiling to aid in the expulsion of the carbonic acid 
gas. The filtered liquid is a solution of sulphate of magnesium 
(>IgS04), crystals of which, Epsom salt (>IgS0„7lI,0) (Mag- 
nesia Sulphas, U. S. P.), may be obtained on evaporating most 
of the water and setting the concentrated solution aside to 
cool. This is an ordinary manufacturing process. Instead of 
magnesite, dolomite, the common magnesian limestone (carbo- 
nate of magnesium and calcium, CaC03,MgC03), may be em- 
ployed, any iron being removed by evaporating the solution 
(filtered from the sulphate of calcium produced) to dryness, 
gently igniting to decompose sulphate of iron, dissolving in 
water, filtering from oxide of iron, and crystallizing. (If 
neither mineral be at hand, the practical student may use a 116 
THE METALLIC RADICALS. 
little of the ordinary manufactured carbonate of pharmacy, 
for the chemical action is almost identical, and it is the chem- 
istry and not, just now, the commercial economy of the matter 
that he is studying. The manufacturer must, of course, com- 
mence with one of the above mineral carbonates furnished by 
nature, from that make his sulphate, and from the latter, as 
will be seen directly, make the pure pulverulent carbonate of 
pharmacy.) 
MgC03 + TLS04 = MgS04 + H20 + C02 
Sulphate of magnesium readily crystallizes in large, colorless, 
transparent, rhombic prisms; but, from concentrated solutions, the 
crystals are deposited in short thin needles, a form more convenient 
for manipulation, solution, and general use in medicine. 
Iron may be detected in sulphate of magnesium by adding the 
common alkaline solution of chlorinated lime or chlorinated soda to 
some aqueous solution of the salt; brown hydrate of iron (Fe26IlO) 
being precipitated. Sulphydrate ammonium will also give a black 
precipitate if iron be present. 
Carbonate of 
magnesium. 
Sulphuric 
acid. 
Sulphate of 
magnesium. 
Water. 
Carbonic 
acid gas. 
Carbonates of Magnesium. 
Second Synthetical Reaction.—To solution of sulphate of 
magnesium add solution of carbonate of sodium, and boil; the 
resulting precipitate is light carbonate of magnesium (Magnesias 
Carbonas Levis, B. P. ; Magnesii Carbonas, U. S. P.), a white, 
partly amorphous, partly minutely crystalline mixture of car- 
bonate and hydrate of magnesium (3MgC03,Mg2H0,4H20, 
B. P.; 4MgC0?,Mg2H0,5H20, U. S. P.). A denser, slightly 
granular precipitate of similar chemical composition (Magnesias 
Carbonas, B. P.) is obtained on mixing strong solutions of the 
above salts, evaporating to dryness, then removing the sulphate 
of sodium by digesting the residue in hot water, filtering, wash- 
ing, and drying the precipitate. 
Sulphate of 
magnesium. 
4MgS04 + 4Na,C03 + H,0 = 3MgC03,Mg2H0 
Carbonate of 
sodium. 
Water. 
Official carbonate of 
magnesium. 
+ 4Na,S04 + C02 
Sulphate of 
sodium. 
Carbonic 
acid gas. 
The official (B. P.) proportions for the light carbonate are 10 of 
sulphate of magnesium and 12 of crystals of carbonate of sodium, 
each dissolved in 80 of cold water, the solutions mixed, boiled for 15 
minutes, the precipitate collected on a filter, well washed, drained, 
and dried over a water-bath. The heavier carbonate is made with 
the same proportions of salts, each dissolved in 20 instead of 80 of MAGNESIUM. 
117 
water, the mixture evaporated quite to dryness, and the residue 
washed by decantation or filtration until all sulphate of sodium is 
removed (shown by a white precipitate—sulphate of barium—ceas- 
ing to form on the addition of solution of chloride or nitrate of 
barium to a little of the filtrate). 
Another (Pattinson s) Process.—Considerable quantities of 
carbonate of magnesium are now prepared by treating dolomite 
(see p. 115) with carbonic acid under pressure. Of the two 
carbonates the magnesian is dissolved first, and is precipitated 
from the clear liquid by the heat of a current of steam. (See 
next reaction.) 
Third Synthetical Reaction.—Pass carbonic acid gas, gene- 
rated as described on page 71, into a mixture of water and car- 
bonate of magnesium contained in a test-tube. After some 
time, separate undissolved carbonate by filtratipn ; the filtrate 
contains carbonate of magnesium dissolved by carbonic acid. 
When of a strength of about 13 grains in one ounce, such a 
solution constitutes “ Fluid Magnesia ” (Liquor Mugnesise Car- 
bonatis, B. P.). This strength of about 3 per cent, at about 
55° F. is reduced to 2$ per cent, at 70° and to about 2 per cent, 
at 80° F. 
Officially, 1 pint is directed to be made from freshly prepared car- 
bonate. The latter is obtained by adding a hot solution of 2 ounces 
of sulphate of magnesium in half a pint of water to one of 2J ounces 
of crystals of carbonate of sodium in another half pint of water, 
boiling the mixture for a short time (to complete decomposition), 
filtering, thoroughly washing the precipitate, placing the latter in 
1 pint of distilled water, and transmitting carbonate acid gas 
through the liquid (say, at the rate of three or four bubbles per 
second) for an hour or two, then leaving the solution in contact 
with the gas under slight pressure for twenty-four hours, and, 
finally, filtering from undissolved carbonate, and, after passing in 
a little more gas, keeping in a well-corked bottle. Slight pressure 
is best created by placing the carbonate and water in a bottle fitted 
with a cork and tubes as for a wash-bottle (p. 96 or 107), conveying 
the gas by the tube which reaches to the bottom, and allowing excess 
of gas to flow out by the upper tube, the external end of which is 
continued to the bottom of a common phial containing about an 
inch of mercury. The phial should be loosely plugged with cotton- 
wool. to prevent loss of metal by spurting during the flow of the 
gas through it. (Each inch in depth of mercury through which 
the gas escapes corresponds to about half a pound pressure on 
every square inch of surface within the apparatus.) 
Heat a portion of the solution ; true carbonate of magnesium con- 
taining combined water (MgC03,3II20) is precipitated. The water 
in this compound is probably in the state of water of crystallization, 
for a salt having the same composition is deposited in crystals by the 118 
THE METALLIC RADICALS. 
spontaneous evaporation of the solution of carbonate of magnesium. 
The official “carbonate” (3MgC03,Mg2H0,4II20) is another of these 
very common hydrous compounds. 
Exposed to cold, the solution of “ fluid magnesia ” sometimes 
affords large thick crystals (MgC03,5II20), which, in contact with 
the air, lose water, become opaque, and then have the composition 
of those deposited by evaporation (MgC03,3H20). 
Oxide of Magnesium (Magnesia). 
Fourth Synthetical Reaction.—Heat light dry carbonate of 
magnesium in a porcelain crucible over a lamp (or in a larger 
earthen crucible in a furnace) till it ceases to effervesce on add- 
ing, to a small portion, water and acid; the residue is light 
magnesia (MgO) (Magnesia Levis, B. P. ; Magnesia, U. S. P.). 
The same operation on the heavy carbonate yields heavy mag- 
nesia (MgO) (Magnesia, B. P. ; Magnesia Ponderosa, U. S. P.). 
Both are sometimes spoken of as “calcined magnesia.” A 
given weight of the official light magnesia occupies three and 
a half times the bulk of the weight of heavy magnesia. 
3MgC03,Mg2H0 = 4MgO + II20 + 3C02 
Official carbonate of 
magnesium. 
Oxide of 
magnesium. 
Water. 
Carbonic 
acid gas. 
A trace only of magnesia is dissolved by pure water. 
Moisten a grain or two of magnesia with water, and place the 
paste on a piece of red litmus-paper ; the wet spot, after a time, 
becomes blue, showing that the magnesia is slightly soluble. 
“ w* rvescing Citrate of Magnesiaso called, is generally 
a mixture of bicarbonate of sodium, citric acid, tartaric acid, 
sugar, either carbonate or sulphate of magnesium, or both, and 
flavoring essences. True citrate of magnesium is easily made 
by heating together calcined magnesia and citric acid; it is 
frequently prescribed in France in doses of two ounces. 
The official “Granulated Citrate of Magnesium” (.Magnesii 
Citrus Gnmulatus, U. S. P.) is made as follows: Mix 11 parts 
of carbonate of magnesium intimately with 33 of citric acid, 
and enough distilled water to make a thick paste; dry this at 
a temperature not exceeding 30° C (86° F.), and reduce it to 
a fine powder. Then mix it intimately with 8 of sugar (No. 
GO powder), 37 of bicarbonate of sodium, and 15 of citric acid 
previously reduced to a very fine powder. Dampen the mass 
with a sufficient quantity of alcohol, and rub it through a No. 
20 tinned-iron sieve, to form a coarse, granular powder. Lastly, 
dry it in a moderately warm place. 
The official Effervescing “ Solution of Citrate of Magne- 
sium ” (Liquor Magnesii Citratis, U. S. P.) is made by dissolv- MAGNESIUM. 
119 
ing carbonate of magnesium in slight excess of solution of 
citric acid, adding syrup of citric acid, placing the diluted 
liquid in an aerated-water bottle, dropping in crystals of bicar- 
bonate of potassium, corking, “ wiring,” and shaking till the 
crystals are dissolved. 
The formula of citrate of magnesium deposited from solu- 
tion is Mg32C6H507,14Ha0. 
Reactions having Analytical Interest (Tests) 
First Analytical Reaction.—Add solution of hydrate or car- 
bonate of ammonium to a magnesian solution (sulphate, for ex- 
ample) and warm the mixture in a test-tube; the precipitation 
of part only of the magnesium as hydrate (Mg2HO) or car- 
bonate (>IgC03) occurs. Add now to a small portion of the 
mixture of precipitate and liquid a considerable excess of solu- 
tion of chloride of ammonium; the precipitate is dissolved. 
This is an important reaction, especially as regards carbonate of 
magnesium, the presence of chloride of ammonium enabling the ana- 
lyst to throw out from a solution barium and calcium by an alkaline 
carbonate, magnesium being retained. The cause of this retention is 
found in the tendency of magnesium to form soluble double salts with 
potassium, sodium, or ammonium. In analysis, the chloride of am- 
monium should be added before the carbonate, as it is easier to pre- 
vent precipitation than to redissolve a precipitate once formed. 
Second Analytical Reaction.—To some of the solution re- 
sulting from the last reaction, add solution of phosphate of 
sodium or ammonium; phosphate of magnesium and ammo- 
nium (MgNH4P04) is precipitated. 3d. To another portion 
add arseniate of ammonium ; arseniate of magnesium and 
ammonium (MgNII4As04) is precipitated. 
Note.—Barium and calcium are also precipitated by alkaline phos- 
phates and arseniates. The other precipitants of magnesium are 
also precipitants of barium and calcium. In other words, there is 
no direct test for magnesium. Hence the analyst always removes 
any barium or calcium by an alkaline carbonate, as above indicated; 
the phosphate of sodium, or arseniate or phosphate of ammonium, 
then becomes a very delicate test of the presence of magnesium. In 
speaking of magnesium tests, the absence of barium and calcium 
salts is to be understood. 
168. Name the natural sources of the various salts of magne- 
sium. 
QUESTIONS AND EXERCISES. 120 
THE METALLIC RADICALS. 
169. Give a process for the preparation of Epsom salt. 
170. Draw diagrams illustrative of the formation of sulphate of 
magnesium from magnesite and from dolomite. 
171. Show by an equation the process for the preparation of the 
official Carbonate of Magnesium. 
172. What circumstances determine the two different states of 
aggregation of the Magnesice Carbonas and Magnesice Carbonas 
Levis f 
173. What are the relations of Magnesia and Magnesia Levis to 
the British official Carbonates of Magnesium ? 
174. How much denser is the one than the other? 
175. Is magnesia soluble in water? 
176. How is “ Fluid Magnesia” prepared? 
177. Mention the effects of heat and cold on 11 Fluid Magnesia.” 
178. How much magnesia (MgO) can be obtained from 1U0 grains 
of Epsom salt? 
179. Calculate the amount of official Carbonate of Magnesium 
which will yield 100 grains of magnesia. 
180. Can magnesium be detected in presence of barium and cal- 
cium ? 
181. Describe the analysis of an aqueous liquid containing salts of 
barium, calcium, and magnesium. 
182. How may magnesium be precipitated from solutions contain- 
ing ammoniacal salts ? 
Quantivalence. 
On reviewing the foregoing statements regarding compounds of 
the three univalent radicals, potassium, sodium, and ammonium, and 
the three bivalent elements, barium, calcium, and magnesium, the 
doctrine of quantivalence will be more clearly understood, and its 
usefulness more apparent. Quantivalence, or the value of atoms, is, 
in short, in chemistry, closely allied to value in commercial barter. 
A number of articles, differing much in weight, appearance, and 
general characters, may be of equal money value; and if these be 
regarded, for convenience, as having a sort of unit of value, others 
worth double as much might be termed bivalent, three times as much 
trivalent, and so on. In like manner, chemical radicals, no matter 
whether elementary, like potassium (K), iodine (I), or sulphur (S), 
or compound, like those of nitrates (NO.,), sulphates (S04), or ace- 
tates (C2II302), have a given chemical value in relation to each other, 
and are exchangeable for, and will unite with, each other to an extent 
determined by that value. 
Most chemical salts apparently, though probably not really, have 
two parts, a basylous and acidulous, the one quantivalently balancing 
the other. The formulae of the chief of these radicals and their quan- 
tivalence are given on the following page. Examples of formulae of 
salts containing univalent, bivalent, and trivalent radicals are also 
appended. QUANTI VALENCE. 
121 
Univalent Radicals, 
or Monads. 
Bivalent Radicals, 
or Dyads. 
Trivalent Radicals, 
or Triads. 
Acidulous. 
Basylous. 
Acidulous. 
Basylous. 
Acidulous. 
Basylous. 
11 
II 
0 
Ca 
CO, 
As 
Cl 
K 
so, 
Mg 
BO, 
Sb 
I 
Na 
co3 
Zn 
C6II507 
Bi 
no 
Nil, 
C20, 
Cu 
AsO, 
f FeiU(ic) 
NO, 
Ag 
C,H,06 Ilg(ic) 
AsO, 
1 °r 
C2II30 
llg(ous) 
s 
1 e(ous) 
c,ii8o5 
( Fevl2(ic) 
Quantivalence or Common Radicals. 
Note.—The hydrogen (II) in the basylous parts of salts has en- 
tirely different functions from the hydrogen (11) in the acidulous part. 
The latter gives compounds commonly termed hydrides (e.g., Aslb,) ; 
in the former the element is the basylous radical of acids (e. g., 
HC1, H2S04). In compound radicals (e. g., C21I302 or NII4) the 
properties of hydrogen are no longer apparent; the chemical force 
resident in the atoms of such radicals seems to be mainly exerted 
in binding those atoms together. 
Examples of Formulas of Salts containing Univalent, Bivalent, and 
Trivalent Radicals. 
The reader will find instructive practice in writing twenty or 
thirty imaginary formulae of salts by placing in juxtaposition acid- 
ulous and basylous radicals, as in the following examples. Just as in 
a pair of scales a 2-lb. weight must be balanced by two 1-lb. weights, 
or a 4-lb. weight by two 2-lb. weights, or by one 3-lb. and one 1-lb. 
weight, so a bivalent radical unites with a bivalent radical or with 
two univalent radicals, a quadrivalent radical with two bivalent radi- 
cals, or with one trivalent and one univalent radical, and so on. 
(R — any basylous Radical.) (R = any acidulous Radical.) 
General formula. 
Examples. 
IVR' .... 
. KI, NaCl, NII4C2H302, AgN03. 
V ‘ 
V 
b 
. CaCl2, Zn2C2H302, I>b2N03(BaN03C2H302). 
R "'R\ . . . 
. Bi3N03, AsH3, SbCl3. 
IV ft" . . ) 
f K2C03, Na2S(),. II2C4H406. 
IVR'R" . . j 
| KIICOj, NaHS04 KNaC4II406. 
R \R"' . . ) 
{ Am3P04, K3C6H507, H3As03. 
W,WR"' . ] 
{ Na/HP04, Na2HAs04. 
R"R" . . . 
. CaCOs,MgO, CuSO„ IlgO, FeS04. 
R">R"\ • • • 
. Ca32P()4, Ca32C6II507. 
R"R 'R'" . . 
. MgAmPCb, CulIAsO.j. 
R "'R"R' . . 
. BiON03. 
R '"R"R". . 
. Bi202C03. 
IV".ft", . . . 
. As203, Sb203, Fe203, Fe23S04. 
IV" R"' . . . 
. BiCfiH507. 
• • • 
. Fe2Cl6, Fe26N03, Fe26C2II302. 122 
THE METALLIC RADICALS. 
Quadrivalent Radicals or Tetrads, Quinquivalent Radicals or Pen- 
tads, and Sexivalent Radicals or Hexads, are known. 
183. Write an exposition of the doctrine of Quantivalence within 
the limits of a sheet of note paper. 
EXERCISE. 
Directions for applying the foregoing analytical 
REACTIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION* 
OF A SALT OF ONE OF THE METALS, BARIUM, CALCIUM, 
Magnesium. 
Add yellow chromate of potassium to a portion of the solu- 
tion to be examined ; a precipitate indicates barium. 
If no barium is present, add chloride and carbonate of ammo- 
nium, and boil; a precipitate indicates calcium. 
If barium and calcium are proved to be absent, add chloride 
of ammonium, ammonia, and then either phosphate of sodium 
or arseniate of ammonium; a white granular precipitate indi- 
cates magnesium. 
Ammonia is here added to yield the necessary elements to ammo- 
nio-magnesian phosphate or ammonio-magnesian arseniate, both of 
which are highly characteristic precipitates; and chloride of Ammo- 
nium is added to prevent a mere partial precipitate of the magne- 
sium by the ammonia. 
Directions for applying the foregoing analytical 
REACTIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION 
OF ONE, TWO, OR ALL THREE OF THE METALS, BA- 
RIUM, Calcium, Magnesium. 
Add chromate of potassium to the solution ; barium, if pres- 
ent, is precipitated. Filter, if necessary, and add to the fil- 
trate (that is, the liquid which has run through the filter) chlo- 
ride, hydrate, and carbonate of ammonium, and boil; calcium, 
if present, is precipitated. Filter, if requisite, and add phos- 
phate of sodium; magnesium, if present, is precipitated. 
Note.—Red chromate of potassium must not be used in these op- 
erations, or a portion of the barium will remain in the liquid and be 
thrown down with, or in place of, the carbonate of calcium (vide p. 
102). The yellow chromate must not contain carbonate of potas- 
sium, or calcium will be precipitated with, or in place of, barium. 
* In preparing such solutions for analysis, salts should be selected 
which do not decompose each other. Chlorides will serve in most 
cases, but nitrates and acetates are still more convenient. ALKALI AND ALKALINE EARTH METALS. 
123 
The absence of carbonate is proved by the non-occurrence of 
effervescence on the addition of hydrochloric acid to a little of the 
solution of the chromate, previously made hot in a test-tube. If 
the yellow chromate has been prepared by adding excess of ammo- 
nia to solution of red chromate of potassium, its addition to the 
liquid to be analyzed must be preceded by that of solution of chlo- 
ride of ammonium, the precipitation of a portion of the magnesium 
(by the free ammonia in the yellow chromate) is thus prevented, for 
chloride of ammonium solution is a good solvent of hydrate (and 
carbonate) of magnesium, as already stated on page 119. 
Note 1.—The analysis of solutions containing the foregoing met- 
als is commenced by the addition of chloride of ammonium (AmCl) 
and ammonia (AmllO), simply as a precautionary measure, the for- 
mer compound preventing partial precipitation of magnesium, the 
latter neutralizing acids. The carbonate of ammonium (Am2C03) is 
the important group reagent—the precipitant of barium and calcium. 
Note 2.—In the following, and in subsequent charts of analytical 
processes, the leading precipitants will be found to be ammonium 
salts. These, being volatile, can be got rid of towards the end of 
the operations, and thus the detection of potassium and sodium be 
in no way prevented—an advantage which could not be had if such 
salts as chromate of potassium or phosphate of sodium were the 
group-precipitants employed. 
Note 3.—Acetic, and not hydrochloric or nitric, acid is used in 
dissolving the barium and calcium carbonates, because chromate of 
barium, on the precipitation of which the detection of barium de- 
pends, is soluble in the stronger acids, and therefore could not be 
thrown down in their presence. 
Table of short directions for applying the foregoing 
ANALYTICAL REACTIONS TO THE ANALYSIS OF AN AQUEOUS 
SOLUTION OF SALTS CONTAINING ANY OR ALL OF THE 
METALLIC ELEMENTS HITHERTO CONSIDERED. 
Precipitate 
Ba Ca. 
Wash, dissolve in HC2H302, 
add K2Cr04, and filter. 
M 
Add Am 
Filtrate 
g Am Na K. 
2HP04, shake, filter. 
Precipitate 
Ba* 
Filtrate 
Ca. 
Test by 
Am2C264. 
Precipitate 
Mg. 
Filtrate 
Am Na K. 
Evap. to dryness, ignite, 
dissolve residue in 
Wfl tPl* 
Test for K by PtCl4. 
Test for Na by flame. 
Test orig. sol. for Am. 
To the solution add AraCl, AmllO, Am2C03; boil and filter. 
* It is perhaps scarcely necessary to state that this precipitate is 124 
THE METALLIC RADICALS. 
Note on Classification.—The compounds of barium, calcium, and 
magnesium, like those of the alkali metals, have many analogies; 
the carbonate, phosphate, and arseniate of each is insoluble in 
water, which sufficiently distinguishes them from the members of 
the class first studied. They possess, however, well-marked differ- 
ences, so that their separation from each other is easy. The solu- 
bility of their hydrates in water marks their connection with the 
alkali metals; the slightness of that solubility, diminishing as we 
advance further and further from the alkalies, baryta being most 
and magnesia least soluble in water, points to their connection with 
the next class of metals, the hydrates of which are insoluble in 
water. These considerations must not, however, be over-valued. 
Though the solubility of their hydrates places barium nearest and 
magnesium farthest from the alkali metals, the solubility of their 
sulphates gives them the opposite order, magnesium-sulphate being 
most soluble, calcium-sulphate next, strontium-sulphate third (stron- 
tium is a rarer element, which will be mentioned subsequently), and 
barium-sulphate insoluble in water. These elements are sometimes 
spoken of as the metals of the alkaline earths. 
Note.—In connection with the bivalence of the metals Barium, 
Calcium, and Magnesium, it is interesting to note that just as biva- 
lent acidulous radicals give salts containing two atoms of univalent 
basylous radicals (K2S04, NaHS04, JI2CO:!, KNaC4II406), so biva- 
lent basylous radicals yield salts containing two atoms of univalent 
acidulous radicals, as seen in acetonitrate of barium, BaC2II302N03, 
a salt which is a definite compound, and not a mere mixture of ace- 
tate with nitrate of barium. A very large number of such salts is 
known. 
Distillation. 
The water with which, in analysis, solution of a salt or dilution 
of a liquid is effected should be pure. Well- or river-water is unfit 
for the purpose, because containing alkaline and earthy salts (about 
20 to 60 grains per gallon), derived from the soil through which the 
water percolates, and rain-water is not unfrequently contaminated 
with the dust and debris which fall on the roofs whence it is usually 
collected. Such water is purified by distillation, an operation in 
which the water is by ebullition converted into steam, and the steam 
condensed again to water in a separate vessel, the fixed earthy and 
other salts remaining in the vessel in which the water is boiled. 
chromate of barium (BaCr04), as any reader who has carefully gone 
through the “ foregoing analytical reactions ” will know. The occur- 
rence of chromate of barium at this particular place, however, and 
under the circumstances described, is abundant evidence of the pres- 
ence of barium (in some form or other) in the liquid analyzed— 
which was a part of the problem to be solved by the operator. Sim- 
ilar remarks apply, of course, to the Ca, which is finally precipitated 
as oxalate (Ca0204), to Mg, which is thrown out as ammonio-plios- 
phate (MgAmP04), to Am, Na, and K, and to the elements similarly 
alluded to in the other subsequent tables for “short” directions for 
analysis. 125 
DISTILLATION. 
On the large scale, ebullition is effected in metal boilers having a 
hood or head in which is a lateral opening through which passes 
the steam ; on the small scale, either a common glass flask is em- 
ployed, into the neck of which, by a cork, is inserted a glass tube 
Fig. 28. 
bent to an acute angle, or a retort is used (a, Fig. 28) a sort of long- 
necked Florence llask, dextrously bent near the body by the glass- 
worker to an appropriate angle (hence the name retort,' from retor- 
qneo, to bend back). Condensation is effected by surrounding the 
lateral steam-tube with cold water. In large stills the steam-tube, 
or condensing-worm, is usually a metal (tin) pipe, twisted into a 
spiral form for the sake of compactness, and so fixed in a tub that a 
few inches of one end of the pipe may pass through and closely fit 
a hole bored near the bottom of the tub. Cold water is kept in con- 
tact with the exterior of the pipe, provision being made for a con- 
tinuous supply to the bottom, while the lighter water heated by the 
condensing steam runs off from the top of the column. The con- 
denser for a flask or retort may be a simple glass tube of any size, 
placed within a second much wider tube (a common long, narrow 
lamp-glass answers very well for experimental operations), the inner 
tube being connected at the extremities of the wider by bored corks ; 
a stream of water passes into one end of the inclosed space (the end 
furthest from the retort) through a small glass tube inserted in the 
cork, and out at the other through a similar tube. The common 
(Liebig’s) form of laboratory condenser is a glass tube three-fourths 
of an inch wide and a yard long (6, Fig. 28), surrounded by a 
shorter tin or zinc tube (c, Fig. 28) two inches in diameter, and 
having at each extremity a neck, through which the glass tube 
passes. The ends of the necks of the tin tube, and small portions 
of glass tube near them, are connected by means of a strip of sheet 
caoutchouc carefully bound round, or by short, wide India-rubber 
tubes (d and e, Fig. 28). An aperture near the lowrer part of the 
tin tube provides for the admission of a current of cold water, and 
a similar aperture near the top (g, Fig. 28) allows the escape of 
heated water. The inner tube may thus constantly be surrounded 
by cold water, and heated vapors passing through it be perfectly 
cooled and condensed in anv receiver (f>, Fig. 28). 126 
THE METALLIC RADICALS. 
The official Water (Aqua, U. S. P.) is to contain “ not more than 
1 part of fixed impurities in 10,OCX) parts,” and to be so free from 
organic matter that when tinted rose-red with permanganate of 
potassium the color should not be destroyed after boiling the fluid 
for 5 minutes, or, in the case of Distilled Water, after setting the 
vessel aside, well covered, for ten hours. 
In distilling several gallons of water for analytical or medicinal 
purposes (Aqua Distillata, U. S. P.) the first two or three pints 
should be rejected, because likely to contain ammoniacal and other 
volatile impurities. 
Rectification is the process of redistilling a distilled liquid. Rec- 
tified spirit is spirit of wine thus treated. 
Dry or destructive distillation is distillation in which the con- 
densed products are directly formed by the decomposing influence 
of the heat applied to the dry or non-volatile substances in the 
retort or still. 
EXERCISE. 
184. Write from memory two or three paragraphs descriptive of 
distillation. 
Recapitulation. 
The subject just alluded to (distillation) naturally excites 
wonder respecting the cause of the physical difference between 
solid, liquid, and gaseous water. (Common observation will 
have suggested to the student that the force of heat has much 
to do with the difference, and if he will turn to the chapter 
on latent heat in any book on Physics he will find that, as 
already indicated (p. 84), when ice liquefies by heat a very 
large amount of heat must be used before the slightest rise of 
temperature occurs. Afterwards the addition of heat makes 
the water hotter and hotter until one other point is reached 
(the boiling-point), when here again a great amount of heat is 
absorbed without causing the slightest rise in temperature. 
Afterwards more heat makes the gaseous water hotter and 
hotter, until, like a bar of iron, the steam, under special con- 
ditions, is made red hot or white hot.) Different bodies absorb 
different amounts of heat in changing their physical condition 
from solid to liquid or liquid to gas (or vapor). The amount 
is constant for any one body, hence definite comparative num- 
bers may be used for expressing the latent heats of substances. 
The absorption of heat at particular (liquefying and vapor- 
izing) points must not be confounded with an analogous phys- 
ical action, namely, the absorption of heat which goes on 
when a body is rising in temperature. The amount of this 127 
RECAPITULATION. 
absorption differs with different substances. That is to say, 
if equal weights of several substances, all at the same tem- 
perature, be all heated to a stated higher temperature, very 
different amounts of fuel will be required. The particular or 
specific amount in each case is always the same, hence the 
specific heats of substances may be expressed by numbers. See 
the chapter on “ Specific Heat ” in any manual of Physics. 
But after reading what has been stated respecting the con- 
stitution of matter (pp. 42 to 45), the chemical student will, 
in connection with the subject of distillation, be led, once more, 
to think over the subject of the molecular constitution of solid, 
liquid, and gaseous water, and of the molecular condition of 
bodies generally. As previously stated, little can be told him 
respecting the molecular condition of solids and liquids, for 
temperature and pressure affect them unequally, whence we 
conclude that, though the relation to each other of the mole- 
cules of any one substance is constant, this relation is different 
in different bodies. Different gases, however, are not differ- 
ently affected, but similarly affected by temperature and pres- 
sure, whence we conclude that their molecular constitution— 
the relations of their molecules to one another—is similar. 
Another gas, ammonia, has been brought before the reader 
since the molecular constitution of gases was considered. 
A small quantity of ammonia gas inclosed in the upper part 
of a roughly graduated test-tube over mercury (water would 
dissolve it) and exposed to the continuous action of the electric 
spark by means of wires of platinum fused in the sides of the 
tube, is decomposed into its elements nitrogen and hydrogen, 
the bulk of gas operated on being exactly doubled. This 
expansion is not due to the gaseous molecules receding from 
each other, but to every two molecules becoming four similar- 
sized molecules:— 
N 
II 
II 
II 
N 
II 
H 
II 
N 
N 
II 
II 
II 
II 
II 
II 
Here each space (rectangular, chiefly for convenience in 
printing) represents a molecule, and each letter one atom. 
Each space, if regarded as the side of a double cube, may also, 
for the moment, represent two volumes—such two volumes 
yielding, in the decomposition, one volume of nitrogen and 
three volumes of hydrogen, or the four such volumes of ammo- 128 
THE METALLIC RADICALS. 
nia shown in the diagram yielding two volumes of nitrogen 
and six volumes of hydrogen. 
Remembering that a symbol (of a gas) represents one vol- 
ume, that a formula (jf a gas) always represents two volumes, 
the pupil will now see how full of meaning is such an equation 
as the following, including, as it does, names of the elements, 
number of the atoms, nature of the molecules, number of the 
molecules, weights of atoms of the molecules, and therefore 
weights of bulks of the bodies, and extent of expansion in the 
disunion of the elements, and therefore their extent of con- 
traction in the act of union:— 
2NH3 = N2 + 3II2. 
At this stage the learner is again recommended to 
READ THE PARAGRAPHS ON THE GENERAL PRINCIPLES OF 
Chemical Philosophy, and to return to them from time 
TO time until they are thoroughly comprehended. 
These three elements are classed together for analytical conve- 
nience rather than for more general analogies. 
ZINC, ALUMINIUM, IRON. 
Symbol Zn. Atomic weight 64.9. 
ZINC. 
Source.—Zinc is tolerably abundant in nature as sulphide (ZnS) 
or blende, and carbonate (ZnCO:!), or calamine (from calamus, a 
reed, in allusion to the appearance of the mineral). The ores are 
roasted to expel sulphur, carbonic acid gas, and some impurities, 
and the resulting oxide distilled with charcoal, when the metal 
vaporizes and readily condenses. Zinc is a brittle metal, but at a 
temperature somewhat below 300° F. is malleable, and may be rolled 
into thin sheets. Above 400° it is again brittle, and may then be 
pulverized. At 773° F. it melts, and at a bright red heat is volatile. 
Zinc in exceptionally fine powder ignites spontaneously, especially 
if damp or if stored in a warm place. 
Uses.—Its use as a metal is familiar; alloyed with nickel and cop- 
per it yields german silver, with twice its weight of copper forms 
common brass, and as a coating on iron (the so-called galvanized 
iron) greatly retards the formation of rust. Most of the salts of zinc 
are prepared directly or indirectly from the metal (Zincum, U. S. P.). 
Quantivalence.—The atom of zinc is bivalent, 7a\". 
Molecular Weight.—Some remarks on this point will be made 
under Mercury. ZINC. 
129 
Reactions having («) Synthetical and (l>) Analytical 
Interest. 
(o) Synthetical Reactions. 
Sulphate of Zinc. 
First Synthetical Reaction.—Heat zinc (4 parts) with water 
(20 parts) and sulphuric acid (3 fl. parts) in a test-tube (or 
larger vessel) until gas ceases to be evolved; solution of sul- 
phate of zinc (ZnS04) results. Filter (to separate the particles 
of lead, carbon, etc., commonly contained in sheet zinc), and 
concentrate the solution in an evaporating-dish; on cooling, 
colorless, transparent, prismatic crystals of Sulphate of Zinc 
(ZnS04,7H20) are deposited (Zinci Sulphas, U. S. IV). 
Zn2 + 2H2S04 + xH40 = 2ZnS04 + 2H* + xll20 
Zinc. 
Sulphuric 
acid. 
Water. 
Sulphate of 
zinc. 
Hydrogen. Water. 
Zinc does not displace hydrogen from the sulphuric acid alone, 
nor from the water alone, yet the mixture affords hydrogen. The 
probable explanation is that as sulphuric acid combines with several 
different quantities of water to form definite hydrous compounds 
(fI2S04,II20; H2S04,2H20; etc.), it is one of these that is de- 
composed with elimination of hydrogen. At present w'e can only say 
that an unknown (x) amount of water is required in the reaction. 
Note.—This reaction affords hydrogen and sulphate of zinc; it 
also develops electricity. Of several methods of evolving hydrogen, 
it is the most convenient; of the two or three means of preparing 
sulphate of zinc, it is the most commonly employed ; and of the 
many reactions w hich may be utilized in the development of dynamic 
electricity, it is at present the cheapest and most manageable. The 
apparatus in which the reaction is effected differs according to the 
requirements of the operator: if the sulphate of zinc alone is wanted, 
an open dish is all that is necessary, the action being, perhaps, 
accelerated by heat; if hydrogen, a closed vessel and delivery-tube ; 
if electricity, square vessels called cells, and certain complementary 
materials, forming altogether what is termed a battery. In each 
operation for one product, the other two are commonly wasted. It 
would not he difficult for the operator, as a matter of amusement, to 
construct an apparatus from which all three products should be col- 
< lected. 
Purification.—Impure sulphate of zinc may be purified in the 
same manner as impure chloride (see next reaction). 
Sulphate of zinc is isomorphous with sulphate of magnesium, and 
like that salt, loses six-sevenths of its water of crystallization at 
212° F. 
Chloride of Zinc. 
Second Synthetical Reaction.—Dissolve zinc in hydrochloric 
acid mixed with half its hulk of water; the resulting solution 130 
THE METALLIC RADICALS. 
contains chloride of zinc. Evaporate the liquid till no more 
steam escapes; Chloride of Zinc (ZnCl2) in a state of fusion 
remains, and on cooling is obtained as an opaque white solid 
(Zinci CIdoridum, U. 8. P.). 
It is soluble in water, alcohol, or ether. 
Zn2 + 4HC1 = 2ZnCl2 + 2II2 
Zinc. 
Hydrochloric 
acid. 
Chloride 
of zinc. 
Hydrogen. 
This reaction is analogous to that previously prescribed. The 
Burnett deodorizing or disinfecting liquid is solution of chloride of 
zinc. 
Purification of Chloride or Sulphate of Zinc.—Zinc sometimes 
contains traces of iron or lead; and these, like zinc, are dissolved 
by most acids, with formation of soluble salts; they may be recog- 
nized in the liquids by applying the tests described hereafter to a 
little of the solution in a test-tube. Should either be present in the 
above solution, a little chlorine-water is added to the liquid till the 
odor of chlorine is permanent, and then the whole well shaken with 
some hydrate of zinc or the common official “carbonate'’ of zinc 
(really hydrato-carbonate—see p. 131). In this way iron is precipi- 
tated as ferric hydrate, and lead as peroxide :— 
* 2Fe€l2 + Cl2 = * Fe2Cl6 
Fe2Cl6 + 3ZnCOa + 3H20 = Fe26IIO + 3ZnCl2 + 3C02 
Ferrous chloride. 
Chlorine. 
Ferric chloride. 
Ferric 
chloride. 
Carbonate 
of zinc. 
Water. 
Ferric hydrate. 
Chloride 
of zinc. 
Carbonic 
acid gas. 
Chloride 
of lead. 
PbCl2 + Cl2 + 2ZnC03 = Pb02 + 2ZnCI2 + 2C02 
Chlorine. 
Carbonate 
of zinc. 
Peroxide 
of lead. 
Chloride 
of zinc. 
Carbonic 
acid gas. 
In the British Pharmacopoeia the presence of impurities in the zinc 
is assumed, and the process of purification just described incorporated 
with the process of preparation of Zinci Chloridum, Liquor Zinci 
Chloridi, and Zinci Sulphas. In the purification of the sulphate of 
zinc, the action of chlorine on any ferrous sulphate will result in the 
formation of ferric sulphate as well as ferric chloride :— 
6FeS04 + Clfi = 2(Fe23S04) + Fe2Cl6; 
carbonate of zinc will then give chloride as well as sulphate of zinc, 
and thus the whole quantity of sulphate of zinc be slightly contami- 
nated by chloride. On evaporating and crystallizing, however, the 
chloride of zinc will be retained in the mother-liquor. This process 
admits of general application. 
For Liquor Zinci Chloridi, B. P., 1 pound of zinc is placed in a 
mixture of 44 fluidounces of hydrochloric acid and 20 of water, the 
* It will be noticed that the iron is represented, in these equations, 
as exerting both bivalent and trivalent activity; this will be alluded 
to when iron conies under consideration. ZINC. 
131 
mixture ultimately warmed until no more gas escapes, filtered into a 
bottle, chlorine-water added until the liquid after shaking smells 
fairly of chlorine, about half an ounce or somewhat more of carbonate 
of zinc shaken up with the solution until a brown precipitate (of fer- 
ric hydrate or peroxide of lead, or both) appears, the whole filtered, 
and the filtrate evaporated to 40 fluidounces. One fluidounce con- 
tains 366 grains of chloride of zinc. If there is reason to believe 
that neither iron nor lead is present in the zinc, the treatment with 
chlorine-water and carbonate of zinc may be omitted. The Liquor 
Zinci Chloridi, U. S. P., is prepared by a somewhat similar process, 
nitric acid, however, is used instead of chlorine-water; the solution 
contains “about 50 per cent, of the salt (ZnCl2),'’ sp. gr. 1.555. It 
is miscible with alcohol in all proportions, indicating absence of 
basic chloride of zinc. 
Bromide of Zinc, ZnBe2 (Zinci Bromidum, U. S. P.) may be made 
by the action of zinc on hydrobromic acid and evaporation to dry- 
ness. It is a white powder, but may be sublimed in needles. 
Iodide of Zinc, Znl2 (Zinci Iodidum, U. S. P.) may be made from 
its elements. It is a white powder, but when volatilized condenses 
in acicular prisms. 
Carbonate of Zinc 
Third Synthetical Reaction.—To solution of any given 
quantity of sulphate of zinc in twice its weight of water (in 
a test-tube, evaporating-basin, or other large or small vessel), 
add about an equal quantity of carbonate of sodium, also dis- 
solved in twice its weight of water, and boil; the resulting 
white precipitate is so-called Carbonate of Zinc (Zinci Car- 
honas, B. P., Zinci Carbonas Prsecipitatus, U. S. P.), a mix- 
ture of carbonate (ZnC03) and hydrate (Zn2HO), in the pro- 
portion of two molecules of the former and three of the latter. 
It may be washed, drained, and dried in the usual manner. It 
is used in the arts under the name of zinc-white. 
5ZnS04 + 3H„0 + 5Na2C03 = 2ZnC0:„3ZnH202 + 3C02 
Official carbonate Carbonic 
Sulphate 
of ziuc. 
Water. 
Carbonate 
of sodium. 
+ 5NasS04 
Official cavljonate 
of ziuc. 
Carbonic 
acid gas. 
Sulphate 
of sodium. 
Acetate of Zinc. 
Fourth Synthetical, Reaction.—Collect in a filter the pre- 
cipitate obtained in the last reaction, wash with distilled water, 
and dissolve a portion in strong acetic acid ; the resulting solu- 
tion «ontains acetate of zinc (Zn2C.iH:i02), and, on evaporating 
and setting aside for a day, yields lamellar pearly crystals 
(Zn2CaII30J,3H20) (Zinci Acetas, U. 8. P.). 132 
THE METALLIC RADICALS. 
Official carbonate 
of zinc. 
2ZnC03,8ZnH202 + 10HCJTA = 5(Zn2CsHs02) + 8H20 
Acetic 
acid. 
Acetate of zinc. 
Water. 
+ 2C02 
Carbonic 
acid gas. 
Another process consists in digesting oxide of zinc in acetic 
acid, heating the mixture to boiling-point, filtering while hot, 
and setting aside the clear solution to crystallize. 
Oxide of Zinc. 
Fifth Synthetical Reaction.—Dry the remainder of the pre- 
cipitated carbonate (by placing the open filter on a plate over 
a dish of water kept boiling), and then heat it in a small cru- 
cible till it ceases to effervesce on the addition of water and 
acid to trial samples taken out of the crucible from time to 
time; the product is Oxide of Zinc (Zinci Oxidum, U. S. P.). 
2ZnC03,3ZnH202 = 5ZnO + 3H20 + 2C02 
Note.—This oxide is yellow while hot, and of a very pale yellow 
or slight buff tint when cold, not actually white, like the oxides pre- 
pared by the combustion of zinc in air. The latter variety occurs in 
commerce under the name of Ilubbuck’s oxide of zinc. Its prepara- 
tion can only be practically accomplished on the large scale, but the 
chief features of the action may be observed by heating a piece of 
zinc on charcoal in the blowpipe-flame (Fig. 29) till it burns; flocks 
escape, float about in the air, and slowly fall. These are the old 
Flores Zinci, Lana Philosophica, or Nihilum Album. 
Official carbonate 
of zinc. 
Oxide of 
zinc. 
Water. 
Carbonic 
acid gas. 
Fig. 29. 
Fig. 30. 
The Blowpipe. 
A clear blowpipe-flame consists more or less of two portions 
(see Fig. 30), an inner cone, at the apex of which are hot gases 
greedy of oxygen, and an outer cone, at the apex of which is ZINC. 
133 
excess of hot oxygen. At the latter point oxidizable metals, 
etc. are readily oxidized, as in the foregoing experiment, and 
that part of the flame is therefore termed the oxidizing flame; 
in the inner flame oxides and other compounds (a grain of 
acetate of lead may be employed for illustration) are reduced 
to the metallic state, hence that part is termed the reducing 
flame. A blowpipe-flame is much altered in character by 
slight variations in the position of the nozzle of the blowpipe, 
by the form of the nozzle, by the force with which air is ex- 
pelled from the blowpipe, and by the character of the jet ot 
gas. 
Valerianate of Zinc. 
Sixth Synthetical Reaction.—Valerianate of Zinc (Zn2C5- 
II902,H20) (Zinri Valeria IMS, U. S. P.) is prepared by mixing 
strong solutions of sulphate of zinc and valerianate of sodium, 
cooling, separating the white pearly crystalline matter, evapor- 
ating at 200° F. to a low bulk, cooling, again separating the 
lamellar crystals, washing the whole product with a small 
quantity of cold distilled water, draining, and drying by ex- 
posure to air at ordinary temperatures. Valerianate of zinc is 
soluble in ether, alcohol, or hot water. 
ZnS04 + 2NaC5HuO, = Na,S04 + Zn2GJIA 
Sulphate 
of ziue. 
Valerianate of 
sodium. 
Sulphate of 
sodium. 
Valerianate 
of zinc. 
Note.—The compounds of zinc described in the foregoing six reac- 
tions are the only ones mentioned in the British Pharmacopoeia; the 
processes are also those of that work. Sulphide and Hydrate of Zinc 
are mentioned in the following analytical paragraphs. The formula 
of Sulphite of Zinc is ZnS03,3H20. 
(It) Reactions having Analytical Interest ( Tests) 
First Analytical Reaction.—To solution of a zinc salt (sul- 
phate, for example) in a test-tube, add solution of sulphydrate 
of ammonium (NHJIS) ; white sulphide of zinc (ZnS) is pre- 
cipitated, insoluble in acetic, but soluble in the stronger acids. 
Note.—This is the only white sulphide that will be met with. Its 
formation, on the addition of the sulphydrate of ammonium, is 
therefore highly characteristic of zinc. If the zinc salt contains 
iron or lead as impurities, the precipitate will have a dark ap- 
pearance, the sulphides of those metals being black. Hydrate of 
aluminium, which is also white and precipitated by sulphydrate 
of ammonium, is the only substance sulphide of zinc is likely to 
be mistaken for, and vice versa; but, as will be seen immediately, 
there are good means of distinguishing these from each other. 
Second Analytical Reaction.—To solution of a zinc salt add 134 
THE METALLIC RADICALS. 
solution of ammonia ; white hydrate of zinc (Zn2IIO) is preci- 
pitated. Add excess of ammonia; the precipitate is redis- 
solved. 
This reaction at once distinguishes a ziuc salt from an aluminium 
salt, hydrate of aluminium being insoluble, practically, in ammonia. 
Other Analytical Reactions.—The fixed alkali-hydrates afford 
a similar reaction to that just mentioned, the hydrate of zinc 
redissolving if the alkali is free from carbonate. Carbonate 
of ammonium yields a white precipitate of carbonate and hy- 
drate, soluble in excess. The fixed alkaline carhonates give 
a similar precipitate, which is not redissolved if the mixed 
solution and precipitate be well boiled. Ferrocyanide of 
potassium precipitates wrhite ferrocyanide of zinc (Zn2FeCy6). 
Sulphate of magnesium, which is isomorphous with, and in- 
distinguishable in appearance from, sulphate of zinc, is not pre- 
cipitated from its solutions either by ferrocyanide of potassium 
or sulphydrate of ammonium. 
Antidotes.—There arc no efficient chemical means of counteract- 
ing the poisonous effects of zinc. Large doses, fortunately, act as 
powerful emetics. If vomiting has not occurred, or apparently to 
an insufficient extent, solution of carbonate of sodium (common 
washing salt), immediately followed by white of egg and demulcents, 
may be administered. 
QUESTIONS AND EXERCISES. 
185. Give the sources and uses of metallic zinc. 
186. Explain by a diagram what occurs when zinc is dissolved in 
diluted sulphuric acid. 
187. How may solutions of Chloride and of Sulphate of Zinc be 
purified from salts of iron ? Give equations descriptive of the reac- 
tions. 
188. State the formula of Carbonate of Zinc, and illustrate by a 
diagram the reaction which takes place in its production. 
189. Give an equation showing the formation of Acetate of Zinc. 
190. In what respect does Oxide of Zinc, resulting from the igni- 
tion of the carbonate, differ from that produced during the combus- 
tion of the metal ? 
191. How is Valerianate of Zinc prepared? 
192. What are the properties of Valerianate of Zinc? 
193. Name the more important tests of Zinc. 
194. llow would you distinguish, chemically, between solutions of 
Sulphate of Zinc and Alum? 
195. Describe the treatment in cases of poisoning by the salts of 
zinc. 
196. Give reactions distinguishing Sulphate of Zinc from Sulphate 
of Magnesium. ALUMINIUM. 
135 
ALUMINIUM. 
Symbol Al. Atomic weight 27 
Note.—In the formulae of aluminium salts it will be observed 
that to one atom of metal there are three atoms of other univalent 
radicals; hence, apparently, the atom of aluminium is trivalent, 
Alr//. But possibly it is quadrivalent; for one molecule of alu- 
minium compounds includes two atoms of the metal, three-fourths 
only of whose power may be supposed to be exerted in retaining the 
other constituents of the molecule, the remaining foiirth enabling the 
aluminium atoms themselves to keep together. This is graphically 
shown in the following formula of chloride of aluminium (A12C16) 
from Frankland’s “Lecture Notes for Chemical Students,’ which 
Cl Cl 
I I 
Cl II Al— Cl 
I I 
I I 
Cl Cl 
represents each aluminium atom as a body having four arms or 
bonds, three of which are engaged in grasping the arms of univ- 
alent chlorine atoms, while the fourth grasps the corresponding 
arm of its brother aluminium atom. Such graphic formulae, as 
they are called, are useful in facilitating the acquirement of hy- 
potheses regarding the constitution of chemical substances, espe- 
cially if the error be avoided of supposing that they are pictures 
either of the position or absolute power of atoms in a molecule, or 
indeed, the true representation of a molecule at all; for on this 
point man knows little or nothing. 
Source.—Aluminium is very abundant in nature, chiefly as silicate, 
in clays, slate, marl, granite, basalt, and a large number of minerals. 
Mica consists chiefly of silicates of aluminium, iron, and potassium. 
Rotten-stone is a soft and friable aluminium silicate containing a little 
organic matter. The sapphire and ruby are almost pure oxide of 
aluminium. The metal aluminium is obtained from the double 
chloride of aluminium and sodium, by the action of metallic sodium, 
the source of the chloride being the mineral bauxite—a more or less 
ferruginous hydrate of aluminium. 
Aluminium-bronze is an alloy of ten parts of aluminium with 
ninety of copper. 
Alum (Alumen, U. S. P.), a double sulphate of aluminium and 
potassium (A123S04,K2S04,24H20), may be obtained from aluminous 
schist (from axi-crhc, sc hist os, divided), a sort of pyritous slate or shale, 
by exposure to air ; oxidation and chemical change produce sulphate 
of aluminium, sulphate of iron, and silica, from the silicate of 
aluminium and bisulphide of iron (iron pyrites) originally present 
in the shale. The sulphate of aluminium and sulphate of iron are 
dissolved out of the mass by water, and sulphate of potassium 136 
THE METALLIC RADICALS. 
added; on concentrating the liquid, alum crystallizes out, while the 
more soluble iron salt remains in the mother liquor. 
Alum is also prepared by directly decomposing the silicate of 
aluminium in the calcined shale of the coal-measures by hot sul- 
phuric acid, sulphate of potassium being added from time to time 
until a solution strong enough to crystallize is obtained. The liquid 
well agitated during cooling deposits alum, in minute crystals, termed 
alum-flour, which is afterwards recrystallized. 
Alums.—There are several alums, iron or chromium taking the 
place of aluminium, and ammonium or sodium that of potassium, all 
crystallizing in an eight-sided form, the octahedron—a sort of double 
pyramid. These are apparently alike in chemical constitution, and 
their general formula (M = either metal) is M///23S04,M/2S04,2-fII20. 
The alum of the manufacturer commonly occurs in colorless, trans- 
parent, octahedral crystals, massed in lumps, which are roughly 
broken up for trade purposes, but still exhibit the faces of octahedra. 
It is liable to contain sulphate of ammonium or sulphate of potas- 
sium, according as one or other is the cheaper. 
Sulphate of Aluminium (A123S04,9II20), or Alum Cake, prepared 
from natural silicates in the manner just described, is a common 
article of trade, serving most of the manufacturing purposes for 
which alum was formerly employed. It is official in the United 
States Pharmacopoeia (Aluminii Sulphas). It may be made by dis- 
solving hydrate of aluminium in diluted sulphuric acid, with subse- 
quent removal of water by evaporation. 
The hydrate of aluminium (Aluminii Hydras, U. S. P.) is to be 
prepared by the addition of solution of alum to solution of carbo- 
nate of sodium, the precipitated hydrate being collected on a filter 
and well washed. 
A126I [0 + 3 U2S04 = A123S04 + 6II20. 
A123S04,K2S04 + 3Na,C05 + 3H20 = Al26IIO + K2S04 + 3Na2S04 
+ 3C02. 
Preparation of Alum.—Prepare alum by heating a small quan- 
tity of powdered pipe-clay (silicate of aluminium) with about twice 
its weight of sulphuric acid for some time, dissolving out the result- 
ing sulphate of aluminium and excess of sulphuric acid by water, 
and adding ammonia to the clear filtered solution only until, after 
well stirring, the excess of acid is neutralized. (If too much am- 
monia be added, the hydrate of aluminium precipitated when the 
ammonia is first poured in will not be redissolved on well mixing 
the whole. Perhaps the readiest indication of neutrality in this 
and similar cases is the presence of a little precipitate after stirring 
and warming the mixture.) On evaporating the clear solution, crys- 
tals of alum are obtained. 
The Ammonio-ferric Alum or Ammonio-ferric Sulphate of Amer- 
ican pharmacy (Ferri et Ammonii Sulphas, U. S. P.) may be made 
by adding sulphate of ammonium to a hot solution of persulphate 
of iron, and setting the liquid aside to crystallize. It forms pale ALUMINIUM. 
137 
violet octahedral crystals expressed by the formula Fe.,3SO,, 
(NH4)2S04,24H20. “ * 
Dried Alum (Alumen Exsiccation, U. S. P.) is alum from which 
the water of crystallization has been expelled by heat, the tempera- 
ture not exceeding 205° C. or 400° F. By calculation from the 
molecular weight of alum, it will be found that the salt contains 
between 45 and 46 per cent, of water. At temperatures above 400° 
ammonium alum is decomposed, sulphate of ammonium and sul- 
phuric anhydride escaping, and pure oxide of aluminium (A1203) 
remaining. Dried alum rapidly reabsorbs water from the atmo- 
sphere. 
Roche alum, or Rock alum (roche, French, rock), is the name of 
an impure native variety of alum containing iron. The article sold 
under this name is sometimes an artificial mixture of common alum 
with oxide of iron. 
Reactions having Analytical Interest. 
First Analytical Reaction.—To a solution of an aluminium 
salt (alum, for example, which contains sulphate of aluminium) 
add sulphydrate of ammonium (NH4HS) ; a gelatinous white 
precipitate of hydrate of aluminium falls :— 
A123S04 + 6AmHS + 6H,0 = Al26HO + 3Am2S04 + 6II2S. 
Second Analytical Reaction.—To a solution of alum add 
ammonia, NH4HO ; hydrate of aluminium falls : add excess of 
ammonia; the precipitate is, practically, insoluble. 
Principle of Dyeing by help of Mordants.—The precipitated 
hydrate of aluminium, or alumina, has great affinity for vege- 
table coloring-matters and also for the fibre of cloth. Once 
more perform the above experiment, but before adding the 
ammonia introduce some decoction of logwood, solution of 
cochineal, or other similar colored liquid, into the test-tube. 
Add now the ammonia, and set the tube aside for the alumina 
to fall; the latter takes down with it all the coloring principle. 
In dye-works the fabrics are passed through liquids holding 
the alumina hut weakly in solution, and then through the color- 
ing solutions; from the first bath the fibres abstract alumina, 
and from the second the alumina abstracts coloring-matter. 
Some other metallic hydrates, notably those of tin and iron, 
resemble alumina in this property ; they are all termed mor- 
dants (from mordens, biting) ; the substances they form with 
coloring-matters have the name of lakes. 
Third Analytical Reaction.—To the alum add solution of 
potash; again hydrate of aluminium falls. Add excess of 
potash, and agitate; the precipitate dissolves. 
Hydrate of aluminium may be precipitated from this solu- 138 
THE METALLIC RADICALS. 
tion by neutralizing the potash with hydrochloric acid, and 
adding ammonia until, after shaking, the mixture has an am- 
moniacal smell, or by adding solution of chloride of ammonium 
to the potash liquid. But the former way is the better; for it 
is difficult to know when a sufficiency of the chloride of am- 
monium has been poured in, whereas reaction with blue and 
red litmus-paper at once enables the operator to know when 
excess of hydrochloric acid or ammonia has been added. 
Alkaline phosphates, arseniates, and salts of other acidulous 
radicals also decompose solutions of aluminium salts and produce 
insoluble compounds of that metal, with the several acidulous 
radicals, but the resulting precipitates are of no special interest. 
QUESTIONS AND EXERCISES. 
197. What is there remarkable about the quantivalence of alu- 
minium ? 
198. Practically, what is the quantivalence of the atom of alu- 
minium ? 
199. Enumerate the chief natural compounds of aluminium. 
200. Write down a formula which will represent either of the 
Alums. 
201. Which alum is official, and commonly employed in the 
arts ? 
202. State the source and explain the formation of alum. 
203. What is the crystalline form of alum? Work a sum showing 
how much Pried Alum is theoretically producible from 100 pounds 
of alum. Ans. 52 lbs. 6 oz. 
204. Show by figures how ordinary ammonium alum is- capable of 
yielding 11.356 per cent, of alumina. 
205. Why are aluminium compounds used in dyeing? 
206. How are salts of aluminium analytically distinguished from 
those of zinc? 
IRON. 
Sources.—Compounds of iron are abundant in nature. Magnetic 
Iron Ore, or Loadstone {Lodestone or Leadstone, from the Saxon 
Icedan, to lead, in allusion to its use, or rather to the use of magnets 
made from it, in navigation), is the chief ore from which Swedish 
iron is made ; it is a mixture of ferrous and ferric oxides (Fe0,Fe203). 
Much of the Russian iron is made from Specidar Iron Ore (from 
speculum, a mirror, in allusion to the lustrous nature of the crystals 
of this mineral). This and Bed Haematite (from alga, haima, blood, 
so named from the color of its streak), an ore raised in Lancashire, 
are composed of ferric oxide only (Fe20;i). Brown Haematite, an 
Symbol Fe. Atomic weight 55.9. IRON. 
139 
oxyhydrate, is the source of much of the French iron. Spathic Iron 
Ore (from spatha, a slice, in allusion to the lamellar structure of the 
ore) is a ferrous carbonate (FeC03). An impure ferrous carbonate 
forms the Clay Ironstone, whence most of the English iron is derived. 
The chief Scotch ore is also an impure carbonate, containing much 
bituminous matter; it is known as Black Band. Iron Pyrites (from 
nvp, pur, fire, in allusion to the production of sparks when sharply 
struck) (FeS2) is a yellow lustrous mineral, of use only for its 
sulphur. As met with in coal it is commonly termed coal brasses. 
Ferrous carbonate (FeC03), chloride (FeCl2,4II20), and sulphate 
(FeS04,7II20) sometimes occur in springs, the water of which is 
hence termed chalybeate (chalybs, steel). 
Process.—Iron is obtained from its ores by processes of roasting, 
and reduction of the resulting impure oxide with coal or charcoal in 
the presence of chalk, the latter uniting with the sand, clay, etc. to 
form a fusible slag. The cast iron thus produced may be converted 
into wrought iron by burning out the 4 or 5 per cent, of carbon, 
silicon, and other impurities present, by oxidation in a furnace, an 
operation which is termed puddling. Steel is iron containing from 
one to two per cent, of carbon, and is made by the now celebrated 
Bessemer process of burning out from cast iron the variable amount 
of carbon it contains, and then adding melted iron containing a 
known proportion of carbon. The official varieties of the metal are 
“metallic iron, in the form of fine, bright, and non-elastic wire” 
(Ferrum, U. S. P.); and “ wrought' iron in the form of wire or 
nails free from oxide” (Ferrum, B. P.), the conditions in which 
it is most easily employed for conversion into its compounds. In 
the form of a fine powder (see 17 Reac.) metallic iron is employed 
as a medicine. 
Properties.—The specific gravity of pure iron is 7.844, of the best 
bar iron 7.7 ; its color is bluish-white or gray. Bar iron requires the 
highest heat of a wind-furnace for fusion, but below that temperature 
assumes a pasty consistence, and in that state two pieces may be 
joined or welded (Germ, wellen, to join) by the pressure of blows 
from a hammer. A little sand thrown on to the hot metal facilitates 
this operation by forming with the superficial oxide of iron a fusible 
slag, which is dispersed by the blows: the purely metallic surfaces 
are thus better enabled to come into thorough contact and enter into 
perfect union. Iron is highly ductile, and of all common metals pos- 
sesses the greatest amount of tenacity. At a high temperature it 
burns in the air, forming oxide of iron. Rust of iron is chiefly red 
oxide of iron, with a little ferrous oxide and carbonate; it is pro- 
duced by action of the moist carbonic acid of the air and subsequent 
oxidation. Steam passed over scrap iron heated to redness gives 
hydrogen gas and black oxide of iron. Iron exposed at a high tem- 
perature to oxidation by a limited amount of steam (Barff) or air 
(Bower) becomes coated with magnetic oxide of so closely coherent 
and adherent a nature that the metal is permanently protected from 
alteration by atmospheric and many other influences. 
Quantivalence.—Iron combines with other elements and radicals 
in two proportions; those salts in which the atom of iron appears to 140 
THE METALLIC RADICALS. 
possess inferior affinities (in which the other radicals are in the less 
amount) are termed ferrous, the higher being ferric salts. In the 
former the iron exerts bivalent (Fe/y), in the latter trivalent activity 
(Fe/// or Fe.2VI). 
The atom of iron is also sometimes considered to be sexivalent, on 
account of the analogy of its compounds with those of chromium, 
which is sexivalent, if the formula of its fluoride (CrF6) be correct, 
and because the composition of ferrate of potassium (K2Fe04), a 
deep purple salt obtained on passing chlorine through a concentrated 
solution of potash in which fresh ferric hydrate is suspended, is best 
explained on the assumption of the sexivalence of its iron. 
Why the quantivalence of the atom of iron should vary is not at 
present known. 
The Nomenclature of Iron Salts.—For educational and descrip- 
tive purposes the two classes of iron compounds are very conveniently 
spoken of as ferrous and ferric, the syllable 11 ferr” common to all 
indicating their allied ferruginous character, the syllables ous and ic 
indicating the lower and higher class respectively—functions fulfilled 
by these two syllables in other similar cases (sulphurous and sul- 
phuric, mercurous and mercuric). Officially the iron salts are known 
by other names, thus, Sulphate of Iron (Ferri Sulphas) and Phos- 
phate of Iron (Ferri Phosphas), names which are chemically inex- 
plicit, for there are two sulphates, and two phosphates, and the terms 
do not define which salt is intended. Consistency and uniformity 
would demand that the names Ferrous Sulphate, Ferrous Phosphate, 
or similar terms, should be employed. Practically, however, the old 
names cause no confusion, inasmuch as, commonly, only one sulphate, 
phosphate, etc. are used in medicine; moreover, the higher salts 
usually have the prefix per attached (as persulphate, perchloride). 
These names are already well known, can be easily rendered in Latin, 
and then admit of simple abbreviations and adaptations such as are 
employed in prescriptions, advantages not possessed by the more 
rational terms. While, therefore, the comprehension of the chem- 
istry of iron is rendered simple and intelligible by the use of the 
terms ferrous and ferric, the employment of older and less definite 
names may very well be continued in pharmacy as being practically 
more convenient. 
Reactions having («.) Synthetical and ([L) Analytical 
Interest. 
(a) Synthetical Reactions. 
Green Sulphate of Iron. Ferrous Sulphate. 
FERROUS SALTS. 
First Synthetical Reaction.—Place iron (small tacks) in sul- 
phuric acid diluted with eight times its bulk of water (in a 
test-tube, basin, or other vessel of any required size), accele- 
rating the action by heat until effervescence ceases. IRON. 
141 
Fe, + 2H2S04 + aH20 = 2FeS04 + 2H2 + *11,0 
Iron. 
Sulphuric 
acid. 
Water. 
Ferrous 
sulphate. 
Hydrogen. 
Water 
The solution contains what is generally known as Sulphate 
of Iron, that is, Ferrous Sulphate, the lower of the two sul- 
phates, and will yield crystals of that substance (FeS04,7H20) 
(Ferri Sulphas, U. S. P.) on cooling or on further evaporation; 
or if the hot concentrated solutions be poured into alcohol, the 
mixture being well stirred, the sulphate is at once thrown 
down in minute crystals (Ferri Sulphas Prsecipitatus, U. S. P.). 
At a temperature of 300° F. ferrous sulphate loses six-sevenths 
of its water, and becomes the Ferri Sulphas Exsiceatus, U. S. P., 
a salt used in the preparation of Filu/se Aloes et Fern', U. S. P. 
(See analogous zinc reaction on p. 129.) 
Other Sources of Ferrous Sulphate.—In the laboratory ferrous 
sulphate is often obtained as a by-product in making sulphuretted 
hydrogen:— 
FeS + II2S04 = II2S + FeS04. 
In manufactories it occurs as a by-product in the decomposition of 
aluminous shale, as already noticed (p. 135). 
Ten grains of granulated sulphate of iron dissolved in one ounce 
of water constitute “ Solution of Sulphate of Iron,” B. P. “ The 
solution should be recently prepared.” 
Notes.—Ferrous sulphate is sometimes termed green vitriol. Vit- 
riol (from vitrum, glass) was originally the name of any transparent 
crystalline substance, but afterwards restricted to the sulphates of 
zinc, iron, and copper, which were, and still are, occasionally known 
as white, green, and blue vitriol. Copperas (probably originally 
copper-rust, a term applied to verdigris and other green incrusta- 
tions of copper) is another name for this sulphate of iron, some- 
times distinguished as green copperas, sulphate of copper being blue 
copperas. Solid sulphate of iron is a constituent of Filulce Aloes et 
Ferri, B. P. Ferrous sulphate forms a light-green double salt with 
sulphate of ammonium. 
Ferrous sulphate, when exposed to the air, gradually turns brown 
through absorption of oxygen, ferric oxysulphate (Fe202S04) being 
formed. The latter is not completely dissolved by water, owing to 
the formation of a still lower insoluble oxysalt (Fe405S04) and solu- 
ble ferric sulphate, 5(Fe202S04) Fe405S04 + 3(Fe23S04). 
Iron heated with undiluted sulphuric acid gives sulphurous acid 
gas and ferrous sulphate:— 
Fe2 + 4HzS04 = 2S02 + 2FeS04 + 4II20. 
Carbonate of Iron. Ferrous Carbonate. 
Second Synthetical Reaction.—To solution of ferrous sul- 
phate, boiling, in a test-tube, add solution of bicarbonate of 
sodium (NaHCO.) in recently boiled water ; a white precipitate 142 
THE METALLIC RADICALS. 
of ferrous carbonate (FeC03) is thrown down, rapidly becoming 
light green, bluish green, and, after a long, time, red, through 
absorption of oxygen, evolution of carbonic acid gas, and for- 
mation of ferric oxyhydrate. 
Ferrous 
sulphate. 
FeS04 + 2NaHC03 = FeC03 + Na,SO< + 11,0 + CO, 
Bicarbonate of 
sodium. 
Ferrous 
carbonate. 
Sulphate of 
sodium. 
Water. 
Carbonic 
acid gas. 
Saccharated Carbonate of Iron.—The above precipitate, rapidly 
washed with hot, well-boiled distilled water, and the moist powder 
mixed with sugar, and quickly dried—in short, all possible precau- 
tions taken to avoid exposure to air—forms the saccharated carbo- 
nate of iron (Ferri Carbonas Saccharatus, U. S. P.). 
The official proportions are 10 of the sulphate dissolved in 40 of 
hot water, and 7 of the bicarbonate dissolved in 100 of warm water, 
and each filtered. The former is then added to the latter in a flask, 
the mixture shaken, the precipitate washed by decantation until the 
washings give only a very slight turbidity with chloride of barium, 
drained, and while still somewhat moist mixed with 16 parts of 
sugar, and finally dried over a water-bath. 
Carbonate of iron, mixed with honey and sugar, forms the Massa 
Ferri Carbonatis, U. S. P. 
Ferrous carbonate is said to be more easily dissolved in the stom- 
ach than any other iron preparation. It is so unstable and prone to 
oxidation, that it must be washed in water containing no dissolved 
air and mixed with the sugar (which protects it from oxidation) as 
quickly as possible. In making the official compound mixture of 
iron (Mistura Ferri Composite, U. S. P.), “ Griffith's mixture,” the 
various ingredients, including the carbonate of potassium, should 
be placed in a bottle of the required size, space being left for 
the crystals or solution of ferrous sulphate, which should be 
added last, the bottle immediately filled up with the rose-water, 
and securely corked; the minimum of oxidation is thus insured. 
Pilulce Ferri Composite, U. S. P., is made from myrrh, carbonate 
of soda, sulphate of iron, and syrup; carbonate of iron is gradu- 
ally formed. 
FeS04 + K,C03 = FeCOs + K2S04 
Ferrous 
sulphate. 
Carbonate of 
potassium. 
Ferrous 
carbonate. 
Sulphate of 
potassium. 
Arseniate of Iron. Ferrous Arseniate, 
Third Synthetical Reaction, by which the lower arseniate 
of iron, ferrous arseniate (Fern Arsenicas, B. P.) (Fe32As04), 
partially oxidized, is formed. This will be noticed again under 
Arsenicum. 
Phosphates of Iron. a. Ferrous Phosphate, 
Fourth Synthetical Reaction.—To solution of ferrous si 
phate in a test-tube add a little solution of acetate of sodiu IKON. 
143 
then solution of phosphate of sodium ; the lower phosphate of 
iron, ferrous phosphate (Fe32P04) is precipitated (Ferri Fhos- 
phas, B. P.). 
b. Ferric phosphate (see page 152). 
3FeS04 4 2Na2HP04 + 2NaC2H:!02 
Ferrous 
sulphate 
l’hosphate of 
sodium. 
Acetate of 
sodium. 
Fe32P04 + 3Na2S04 + 2HC2H302 
Ferrous 
phosphate 
Sulphate of 
sodium. 
Acetic acid. 
Officially, solutions of 3 ounces of sulphate of iron in a quart of 
water and 21 ounces of phosphate and 1 of acetate of sodium in 
another quart of water, are well mixed, filtered, the precipitate well 
washed, and, to prevent oxidation as much as possible, dried at a 
temperature not exceeding 120° F. These proportions will be found 
to accord with the molecular weights of the crystalline salts, multi- 
plied as indicated in the foregoing equation. 3(FeS0,,7H„0) = 834: 
2(Na2HP04,121120) — - 71 fi ; 2(NaC2II.j02,311,0) = 272. 
The above reaction also occurs in making Syrupus Ferri Phos- 
phatis, B. 1’. The precipitate should be well washed, or red ferric 
acetate may be developed after a time. 
The use of acetate of sodium is to insure the absence of free sul- 
phuric acid in the solution—sulphate of sodium being formed 
together with acetic acid. Sulphuric acid is a powerful solvent of 
ferrous phosphate; acetic acid is only a weak solvent. It is impos- 
sible to prevent the separation of sulphuric acid if only ferrous 
sulphate and phosphate of sodium be employed. The solvent action 
of the sulphuric acid for the ferrous phosphate is still better pre- 
vented by the use of excess of the phosphate of sodium (Price), 
sodium sulphate, and doubtless monosodium phosphate (NaH2P04,- 
II20) resulting. Ferrous phosphate is white, but soon oxidizes and 
becomes slate-blue. 
Fifth Synthetical Reaction.—In a gas- or spirit-flame strongly 
heat sulphur with about twice its weight of iron filings in a 
test-tube (or in an earthen crucible in a furnace); ferrous sul- 
phide (FeS) is formed. When cold, add water to a small por- 
tion, and then a few drops of sulphuric acid; sulphuretted 
hydrogen gas (H,S), known by its odor, is evolved. 
Sulphide of Iron, Ferrous Sulphide. 
FeS + H2S04 - FeS04 + H2S. 
Sticks of sulphur pressed against a white-hot bar of cast iron give 
a pure form of ferrous sulphide. The liquid sulphide thus formed 
is allowed to drop into a vessel of water. Or melted sulphur may 
be poured into a crucible full of red-hot iron nails, when a quantity 
of fluid ferrous sulphide is at once formed and may be poured out 
on to a slab. 144 
THE METALLIC RADICALS. 
Green Iodide of Iron. Ferrous Iodide. 
Sixth Synthetical Reaction.—Place a piece of iodine, about 
the size of a pea, in a test-tube with a small quantity of water, 
and add a few iron filings, small nails, or iron wire. On gently 
warming, or merely shaking if longer time be allowed, the 
iodine disappears, and, on filtering, a clear light-green solution 
of iodide of iron (Fel2) is obtained. 
The official Ferri lodidum, B. P., is formed by gently warming a 
mixture of 3 parts of iodine, 1J of fine iron wire, and 12 of distilled 
water in an iron vessel. When combination is nearly complete (as 
show n by indications of a sea-green tint), boil for a short time until 
the whiteness of the froth proves that the iodine has entirely disap- 
peared. The solution is then filtered and evaporated in a clean 
bright iron saucepan, ladle, or dish until a drop taken out on the 
end of an iron wire stirrer solidifies on cooling. The liquid is 
poured out on a clean smooth slab, broken up and preserved in a 
glass-stoppered bottle. Solid iodide of iron has a crystalline frac- 
ture, is “ green with a tinge of brown ; inodorous, deliquescent, and 
almost entirely soluble in water, forming a slightly green solu- 
tion wdiich gradually deposits a colored sediment and acquires a red 
color.” 
The solid iodide contains about 18 per cent, of water of crystal- 
lization, and a little oxide of iron. It is deliquescent and 
liable to absorb oxygen from the air, with formation of insoluble 
ferric oxyiodide or hydrato-iodide. Iodide of iron thus spoiled 
may be purified by re-solution in water, addition of a little 
more iodine and some iron, warming, filtering, and evaporating 
as before. 
Ferrous bromide (FeBr2), occasionally used in medicine, could be 
made, as might be expected, in the same way as the iodide. Syrupus 
Ferri Brpmidi, U. S. P., contains 10 per cent, of ferrous bromide. 
Ferri lodidum Saccharatum, U. S. P., is made by mixing 6 parts 
of iron, 17 of iodine, and 20 of water, shaking until reaction ceases, 
filtering into 40 parts of sugar of milk, evaporating to dryness 
with frequent stirring, and mixing the product in a mortar with 
20 additional parts of sugar of milk. It is a grayish or yellowish- 
white hygroscopic powder. 
Syrupus Ferri lodidum, U. S. P., contains 10 per cent, of the 
iodide. 
FERRIC SAITS. 
Anhydrous Perchloride of Iron. Ferric Chloride. 
Seventh Synthetical Reaction.—Pass chlorine (generated as 
usual from black oxide of manganese and hydrochloric acid in 
a flask) through sulphuric acid contained in a small bottle, and 
thence by the ordinary narrow glass tubing quite to the bottom 
of a test-tube containing twenty or thirty small iron tacks (or 
a Florence flask containing 2 or 3 ounces of iron tacks), the IRON. 
145 
latter kept hot by a gas-flame; the higher chloride of iron, 
ferric chloride, or the perchloride* of iron (Fe2Cl6), is formed, 
and condenses in the upper part of the tube or flask as a mass 
of small dark, iridescent crystals. When a tolerably thick crust 
of the salt is formed, break off the part of the glass containing 
it, being careful that the remaining corroded tacks are ex- 
cluded, and place it in ten or twenty times its weight of water; 
the resulting solution, poured off from any pieces of glass, is a 
Fig. 31. 
Preparation of Anhydrous Ferric Chloride. 
pure neutral solution of hydrous ferric chloride, and will he 
serviceable in performing analytical reactions. 
Precaution.—The above experiment must be conducted in the open 
air, or in a cupboard having a draught outwards. 
Anhydrous Ferrous Chloride.—In breaking up the tube, small 
scales of a light buff color will be observed adhering to the nails; 
they are crystals of ferrous chloride (FeCl2). 
Note.—Solution of ferric chloride evolves some hydrochloric acid on 
boiling, while a darker colored solution of ferric oxychloride remains. 
Green Chloride of Iron. Hydrous Ferrous Chloride. Solution 
of Hydrous Ferric Chloride. 
Eighth Synthetical Reaction.—Dissolve iron tacks, in a test- 
tube, in hydrochloric acid; hydrogen escapes, and the solution 
on cooling, or on evaporation and cooling, deposits crystallized 
ferrous chloride (FeCl2), associated with four molecules of 
water (4H20) of crystallization (FeCl2,4H20). 
* The prefixes per and hyper used here and elsewhere are from vnep, 
hyper, over and above, and simply mean “the highest” of several. 
Thus perchloride, the highest chloride. 146 
THE METALLIC RADICALS. 
Through a portion of the solution of ferrous chloride pass 
chlorine gas ; the ferrous chloride becomes ferric chloride. 
The excess of chlorine dissolved by the liquid in this experiment 
may be removed by ebullition; but the ferric chloride is slightly de- 
composed at the same time, for the reason just stated. The free 
chlorine may also be carried off by passing a current of air through 
the liquid for some time. 
Ninth Synthetical Reaction.—To another portion of the solu- 
tion of ferrous chloride, in a test-tube, add a little more hy- 
drochloric acid; heat the liquid, and continue to drop in nitric 
acid until the black color it first produces disappears; the re- 
sulting reddish-brown liquid is also solution of ferric chloride. 
Hydrous Ferric Chloride (another process). 
6FeCl2 + 2IINO3 + CHC1 = 3Fe2Cl6 + 2NO + 4H20 
Ferrous 
chloride. 
Nitric 
acid. 
Hydrochloric 
acid. 
Ferric 
chloride. 
Nitric 
oxide. 
Water. 
The black substance is a compound of nitric oxide gas (NO) with 
a portion of the ferrous salt; it is decomposed by heat. 
This is the process for producing the Liquor Ferri Chloridi, U. S. 
P., definite weights of materials being employed and the solution 
of ferrous chloride being poured slowly into the nitric acid. The 
sp. gr. of the Liquor is 1.405. It contains some free hydrochloric 
acid. Percentage of anhydrous chloride, 37.8. 
35 parts of this solution and 65 of alcohol form the Tinctura Ferri 
Chloridi, U. S. P. 
Note.—The spirit in the tincture is unnecessary, useless, and dele- 
terious ; for it acts neither as a special solvent nor as a preservative, 
the offices usually performed by alcohol (Tincturce ct Sued, B. P. 
and U. S. P.), but, unless the liquid contain excess of acid, decom- 
poses the ferric chloride and causes the formation of an insoluble 
oxychloride of iron. Even if the tincture be acid, it slowly loses 
color, ferrous chloride and chlorinated ethereal bodies being formed. 
A Liquor, of similar strength, is doubtless destined to displace the 
tincture altogether. 
A strong solution of ferric chloride, on standing, yields a mass of 
yellow crystals (Ferri Chloridum, U. S. P.) containing Fe2Cl6,12II20, 
or, rarely, red crystals having the formula Fe2Cl6,51120. 
Persulphate of Iron. Ferric Sulphate. 
Tenth Synthetical Reaction.—Dissolve ferrous sulphate with 
about a fifth of its weight of sulphuric acid in water in an 
evaporating-dish, heat the mixture and drop in nitric acid until 
the black color it first produces disappears ; the resulting liquid, 
when made of a certain prescribed strength, is the solution 
of ferric sulphate, or higher sulphate, “ Solution of 'Persul- 
phate of Iron ” of the Pharmacopoeia, a heavy dark-red liquid, IRON. 
147 
sp. gr. 1.320 (Liquor Ferri Tersulphatis, U. S. P.). Liquor 
Fern Subsulphatis, U. S. P. (Monsel’s Solution), is a similar 
fluid, made with less acids, containing, therefore, ferric oxy- 
sulphate, Fe405S04 (sp. gr. 1.555). 
6FeS04 + 3HS04 + 2HN03 = 3(Fe23S04) + 2N0 + 4H20 
Ferrous 
sulphate. 
Sulphuric 
acid. 
Nitric 
acid. 
Ferric 
sulphate. 
Nitric 
oxide. 
Water. 
The black color, as in the previous reaction, is due to a compound 
of ferrous salt with nitric oxide (2FeS04 + NO). 
Note.—In all the reactions in which iron passes from ferrous to 
ferric condition the element assumes different properties, the chief 
one being an alteration from bivalent to trivalent activity. 
The official “ Solution of Normal Ferric Sulphate” or Tersulphate, 
just mentioned, is made by heating a mixture of 15 parts of sul- 
phuric acid, 1 1 of nitric, and 50 of water, and adding 80 of ferrous 
sulphate (about one-fourth at a time) ; then dropping in more nitric 
acid until red fumes cease to be produced and heating until the fluid 
has a reddish-brown color and is free from nitrous odor. Water is 
added to make 200 parts. It contains 28.7 per cent, of anhydrous 
ferric sulphate. 
Acetate of Iron. Ferric Acetate. 
Eleventh Synthetical Reaction.—To a strong solution of ferric 
sulphate (from which free nitric acid has been removed by 
evaporating to dryness and redissolving in water) add an alco- 
holic solution of acetate of potassium (KC2H302), and well 
shake the mixture ; a crystalline precipitate of sulphate of po- 
tassium (K2S04) falls, and ferric acetate (Fe26C2H302) remains 
in solution, forming, when filtered and of definite strength, the 
Tinctura Ferri Acetatis, 13. P. The preparation is unstable. 
Ferric 
sulphate. 
Fe23S04 + 6KC2H302 = 3K2S04 + Fe26C2H302 
Acetate of 
potassium. 
Sulphate of 
potassium. 
Ferric 
acetate. 
The official proportions are 2£ fluidounces of “ Solution of Per- 
sulphate of Iron7’ with 8 fluidounces of rectified spirit, mixed with a 
solution of 2 ounces of acetate of potassium in 10 fluidounces of 
spirit, the whole well shaken frequently during an hour, filtered, and 
the precipitated sulphate of potassium washed by pouring on spirit 
until the filtrate measures 1 pint. A solution four times this strength, 
made from ferric hydrate and glacial acetic acid, is stable: it is di- 
luted with spirit as wanted (-J. Deane and T. Jeaffreson). 
The Solution of Acetate of Iron (Liquor Ferri Acetatis, U. S. P.) 
is an aqueous solution of ferric acetate, containing 33 per cent, of 
Fe26C2H302. It is made by dissolving the ferric hydrate prepared 
from a known quantity of ferric sulphate in a definite weight of 
acetic acid. Sp. gr. 1.160. 50 parts of this solution, 30 of alcohol 
and 20 of acetic ether form the Tinctura Ferri Acetatis, U. S. P. 148 
THE METALLIC RADICALS. 
Perhydrate of Iron. Ferric Hydrate. 
Twelfth Synthetical Reaction.—Pour a portion of the solu- 
tion of ferric sulphate into excess of solution of ammonia ; 
moist ferric hydrate is precipitated (Ferri Oxidum Hydratum, 
U. S. P.). 
Fe23S04 + 6AmH0 = Fe26HO + 3Am2S04 
Ferric 
sulphate. 
Ammonia. 
Ferric 
hydrate. 
Sulphate 
of ammonium. 
Either of the other alkalies (potash or soda) will produce a similar 
reaction ; soda is cheapest, ammonia most convenient. 
Ferric hydrate is an antidote to arsenic if administered directly 
the poison has been taken. 
It converts the soluble arsenic (As203) into insoluble ferrous 
arseniate:— 
2(Fe26HO) + As203 = Fes2As04 + 5II20 + Fe2II0. 
Dried ferric hydrate (having become an oxyhydrate—Fe4044II0) has 
less action on arsenic. Even the moist, recently prepared hydrate 
(Fe26HO) loses much of this power as soon as it has become con- 
verted into an oxyhydrate (Fe4036II0), a change which occurs though 
the hydrate be kept under water (\V. Procter, Jr.). According to 
T. and H. Smith this decomposition occurs gradually, but in an in- 
creasing ratio; so that after four months the power of the moist 
mass is reduced to one-half and after five months to one-fourth. 
Now mere loss of water is not usually followed by any alteration 
of the essential chemical properties of a compound. It would seem, 
therefore, that ferric hydrate (two molecules) (Fe412IIO) probably 
suffers, on standing, actual decomposition into oxyhydrate (Fe4036H0) 
and water (3II20), and does not merely lose water already existing 
in it as water. Ferric hydrate is also far more readily soluble in 
hydrochloric acid, tartaric acid, citric acid, and acid tartrate of 
potassium, than ferric oxyhydrate. Any formula exhibiting ferric 
hydrate (Fe26IIO) as a combination of ferric oxide and water 
(f'e203,3H20) is, apparently, for these and other reasons, incorrect. 
Fern Oxidum Hydratum, cum Magnesia.—As a more trustworthy 
arsenical antidote, a mixture of solution of ferric sulphate and mag- 
nesia is recommended in the United States Pharmacopoeia. Bottles 
containing (a) 100 parts of the official solution of ferric sulphate 
mixed with twice its weight of water, and (!>) 15 parts of magnesia 
well mixed and diluted with water, are to be kept on hand ready 
for immediate use. Their contents are simply mixed, shaken to- 
gether, and administered to the patient. 
Ferric 
sulphate. 
Fe23S04 + 3MgO + 3II./) = 3MgS04 + Fo26IIO 
Magnesia. 
Water. 
Sulphate of 
magnesium. 
Ferric 
hydrate. 
Collect the precipitate on a filter, wash, and dry on a plate 
oyer hot water ; ferric oxyhydrate (Fern Pcroxidum Hydratum, 
Peroxyhydrate of Iron. Ferric Peroxyhydrate. IRON. 
149 
B. P.) (Fe2022H0) remains. When rubbed to powder it is tit 
for use in medicine. 
Fe26HO = Fe2022H0 + 2IL0 
This oxhydrate further decomposes when heated to low redness 
ferric oxide (Fe203) remaining. 
Fe2022II0 == Fe203 -f II20. 
The six univalent atoms of the 110, the characteristic elements of 
all hydrates, are thus, by two successive steps, split up into water 
and oxygen. But between the hydrate and oxide there obviously 
may be another oxyhydrate, in which only 2110 is displaced by CK , 
and such a compound is well known ; it is a variety of brown iron 
ore. The other oxyhydrate, Fe20221I0, is also native (needle iron 
ore), as well as being the Ferri Feroxidum llydratum, B. P. 
“Ferri Peroxidum Ilumidum” Fe///2 OHO 
A variety of brown iron ore . . Fe///20// 4110 
“Ferri Peroxidum llydratum” (needle ore) . . Fe///,0//22H0 
Ferric oxide Fe///20//s 
The moist ferric hydrate, as already stated, when kept for some 
months, even under water, loses the elements of water, and is 
converted into an oxyhydrate having the formula Fe4ll609 (limo- 
nite or brown haematite), which is either a compound of the above 
oxyhydrates (Fe204H0) (Fe2022II0), or is a definite intermediate 
oxyhydrate (Fe4036H0). 
By ebullition with water for seven or eight hours, ferric hydrate 
is decomposed into water and an oxyhydrate having the formula 
Fe4H207 (Saint Giles), which is either a mixture of the official 
oxyhydrate (Fe2022U0) with ferric oxide (Fe203), or a definite in- 
termediate body (Fe4052II0). The relation of these bodies to each 
other will be apparent from the following Table, in which, for con- 
venience, the formulae of ferric hydrate and oxide are doubled :— 
Ferric hydrate (B. P.) (as stalactite) .... Fe4 12110 
Kilbride mineral (?) Fe401()110 
Brown iron ore (Iluttenrode and Raschau) . . Fe4028H0 
Old, or frozen, ferric hydrate (limonite) . . . Fe40:i6II0 
Ferric oxyhydrate (B. P.) (gothite) .... Fe4044I!0 
Boiled ferric hydrate (turgite) Fe405 2110 
Ferric oxide (red haematite) Fe406 
A ferric oxycarbhydrate (Fe40CO38MO) has been obtained by 
Bother. 
The English official ferric oxyhydrate (Fe2022II0), termed in the 
British Pharmacopoeia Hydrated Peroxide of Iron, under the as- 
sumption that it is a compound of ferric oxide and water (Fe20;i,- 
II20), was formerly made by mixing solutions of ferrous sulphate 
and carbonate of sodium and exposing the resulting ferrous car- 
bonate to the air until it was nearlv all converted into ferric oxy- 
Peroxide of Iron. Ferric Oxide. 150 
THE METALLIC RADICALS. 
hydrate; hence its old names, still sometimes seen on old bottles, of 
Ferri Carbonas and Ferri Subcarbonas. 
Ferric Oxide (another process). 
Thirteenth Synthetical Reaction.—Roast a crystal or two of 
ferrous sulphate in a small crucible until fumes cease to be 
evolved; the residue is a variety of ferric oxide (Fe203) or 
peroxide of iron, known in trade as red oxide of iron, colcothar, 
crocus, rouge (mineral), or Venetian red. It has sometimes 
been used in pharmacy in mistake for the official oxyhydrates 
(vide 12th Synthet. lleac.\ from which it differs not only in 
composition, but in the important respect of being almost in- 
soluble in acids. 
The Scale Compounds of Iron. 
Fourteenth Synthetical Reaction.—Repeat the twelfth reac- 
tion, introducing a little solution of citric or tartaric acid, or 
acid tartrate of potassium, before adding to the alkali (soda, 
potash, or ammonia), and notice that now no precipitation of 
ferric hydrate occurs. This experiment serves to illustrate, not 
the manufacture of a scale compound, but the chemistry of the 
manufacture. The effect is due to the formation of double 
compounds, termed Ammonio-Citrate, Potassio-Citrate, Am- 
monio-Tartrate, Potassio-Tartrate, and similar Sodium com- 
pounds of Iron, which remain in solution along with the second- 
ary product—sulphate of the alkali metal. Such ferric com- 
pounds, made with certain prescribed proportions of recently 
prepared ferric hydrate (from which all alkaline sulphate has 
been washed), and the respective acids (tartaric or citric) or 
acid salts (acid tartrate of potassium), etc., and the solutions 
evaporated to a syrupy consistence, and spread on flat plates 
till dry, form t}ie scale preparations known as Ferri et Ammo- 
nii Citrus, U. S. P., Ferri Citrus, U. S. P. (also Liquor Ferri 
Citratis, U. S. P.), Ferri et Ammonii Tartras, U. S. P., and 
Ferri Fotassio-tartras, or rather Ferrurn Tartaratvm, B. P., 
Ferri et Potassii Tartras, U. S. P. A mixture of citrate of 
iron and ammonium with citrate of strychnine yields, on evap- 
oration, Ferri et Strychnin se Citras, U. S. P. A mixture of 
ferric citrate with citrate of ammonium and citrate of quinine 
yields, by similar treatment, the well-known scales of Ferri et 
Quininse Citrus, TJ. S. P. 
Specimens of these substances may be prepared by attending 
to the following details. It is essential, first, that the ferric 
hydrate be thoroughly washed, or an insoluble oxysulphate will IRON. 
151 
be formed; second, that the ferric hydrate he rapidly washed, 
or an insoluble ferric oxyhydrate will be produced; thirdly, 
that the whole operation be conducted quickly, or reduction to 
green ferrous salt will occur ; fourthly, that the solutions of the 
salts be not evaporated at a higher temperature than that stated, 
or decomposition will take place; and fifthly, that the full 
quantities of ferric hydrate be employed. 
In the pharmacopoeial processes for the scale compounds, the ferric 
hydrate is in each case freshly made from solution of ferric sulphate 
by precipitation with solution of ammonia, 
Fe23S04 + 6AmIIO = Fe26HO + 3Am,S04 
Ferric 
sulphate. 
Hydrate of 
ammonium. 
Ferric 
hydrate. 
Sulphate of 
ammonium. 
the solution of ferric sulphate being made of a definite strength (see 
p. 146) from a known weight of ferrous sulphate. The reason for 
adopting this course is that ferric hydrate is unstable and cannot be 
weighed, because it cannot be dried without decomposing and be- 
coming insoluble, as explained under the 12th reaction. 
Ferri Citrus, U. S. P., and Ferri et Ammonii Citrus, U. S. P.— 
Ferric hydrate is dissolved in solution of citric acid, and the whole 
evaporated to dryness without or with ammonia. 
To prepare the ferric hydrate, dilute 105 parts of official solution 
of ferric sulphate with water; pour this into water containing excess 
of solution of ammonia. (If the opposite course were adopted, the 
alkaline liquid poured into the ferric solution, the precipitate would 
contain ferric oxysulphate, or hydrato-sulphate; which interferes 
with the brilliancy of the scales.) Thoroughly stir the mixture (it 
will smell strongly of ammonia, if enough of the latter has been 
added), allow the precipitate to subside, pour away the supernatant 
liquid, add more water, and repeat the washing until a little of the 
liquid tested for by-product (sulphate of ammonium) by solution of 
chloride or nitrate of barium ceases to give a white precipitate (sul- 
phate of barium). Collect the ferric hydrate on a filter, drain, and 
place in it, while still moist, 30 parts of citric acid, in an evaporat- 
ing-basin, over a water-bath; stir frequently, until the hydrate has 
dissolved. Filter, and either evaporate until the liquid weighs 100 
parts (Liquor Ferri Citratis, U. 8. P., sp. gr. 1.260; strength, 35.5 
per cent, of Fe22C8H507) or evaporate to a syrup at 60° C. and spread 
on glass plates to dry (Ferri Citrus, U. S. P., Fe22C6H507,61I2U), or 
to 3 parts of the Liquor add 1 of ammonia-water and evaporate to 
form scales (Ferri et Ammonii Citrus, U. 8. P.). 
Ferri et Quinines Citrus, U. S. P., is made by dissolving 12 parts 
of pure quinine, (dried at 100° C.) and 88 parts of citrate of iron in 
water, evaporating and scaling. Liquor Ferri et Quinines Citratis, 
U. S. P., contains citrate of iron and ammonium and citrate of qui- 
nine. 
Ferri et Strychnines Citrus, U. S. P., is prepared by mixing one 
part of strychnine and one of citric acid with a solution containing 
98 parts of citrate of iron and ammonium, evaporating the mixture 152 
THE METALLIC RADICALS. 
at a temperature not exceeding 60° C. or 140° F. to a syrupy con- 
sistence, and scaling in the usual way by spreading it upon plates 
of glass. 
Ferri et Potassii Tartras, U. S. P.—Ferric hydrate is dissolved in 
solution of acid tartrate of potassium with a little ammonia, and 
the whole evaporated to dryness. 
The ferric hydrate obtainable from twelve parts of the official 
solution of ferric sulphate by the action of ammonia, in the manner 
detailed in the previous paragraphs, is mixed (in a mortar), while 
still moist but well drained, with four parts of acid tartrate of potas- 
sium. The whole is then heated in a dish over a water-bath to a 
temperature not exceeding 140° F., and the mixture kept warm 
until nothing more will dissolve; a little ammonia added and the 
clear fluid evaporated at a temperature not exceeding 140° F. 
(greater heat causes decomposition), and, when the mixture has 
the consistence of syrup, spread on panes of glass and allowed to 
dry (in aiiy warm and light place shown by a thermometer to be 
not hotter than 140° F.). The dry salt is then obtained in flakes. 
It should be kept in well-closed bottles. 
Ferri et Amrnonii Tartras, U. S. P., is made by saturating .solu- 
tion of acid tartrate of ammonium with ferric hydrate, evaporating, 
and scaling. The acid tartrate is prepared by exactly neutralizing 
half of any quantity of tartaric acid by carbonate of ammonium, 
and then adding the other half. 
The foregoing are the only official scale preparations of iron. 
Many others of similar character might be formed. The Citrate 
dissolves slowly in cold but readily in warm water. None crystal- 
lize or give other indications of definite chemical composition. 
Their properties are only constant so long as they are made with 
unvarying proportions of constituents. Want of chemical com- 
pactness, the loose state in which the iron is combined, precludes 
their recognition as well-defined chemical compounds, yet possibly 
enables them to be more readily assimilated as medicines than some 
of the more definite ferrous and ferric salts. 
A definite ferrous tartrate (FeC4II406) and ferrous citrate 
(FeIIC6H507,II20) have been' obtained by reaction of iron and 
acid in hot water. They occur as white masses of microscopic 
crystals. A sodioferrous citrate (FeNaC6II507) and hydrato-citrate 
(FeNaJIOCgHsO,) may be obtained in scales (Pother). 
Ferric phosphate (Fe22P04), when freshly precipitated, is soluble 
in solution of citrates of the alkali-metals, and the mixture, on 
evaporation on glass plates, yields scales. The official (U. S. P.) 
Ferri Phosphas is to be made by adding 6 parts of phosphate of 
sodium to an aqueous solution of 5 parts of citrate of iron, evap- 
orating and scaling. It is a mixture of ferric phosphate and citrate 
of sodium. 
Wine of Iron, or “ Steel ” wine (Vinum Ferri, B. P.), made by 
digesting iron wire in sherry wine, probably contains tartrate of 
potassium and iron and other iron salts, formed by action of the 
metal on the acid tartrate of potassium and tartaric, citric, malic, 
and acetic acid present in the wine. Vinum Ferri Citratis, U. S. P., IRON. 
153 
contains ammonio-citrate of iron ; Vinum Ferri Amarum, U. S. P. 
contains citrate of iron and quinine. 
Black Hydrate of Iron. Ferroso-ferric Hydrate, 
Ferri Oxvlum Magneticum, B. P. 
Fifteenth Synthetical Reaction.—To two-thirds of a small 
quantity of a solution of ferrous sulphate add a little sulphuric 
acid; warm, and gradually add nitric acid, as described in the 
tenth reaction, care being taken not to allow one drop more 
nitric acid than necessary to fall into the test-tube. Add the 
other third of ferrous sulphate, shake, and pour the liquid into 
excess of an alkali; black (at first brown) hydrate of iron, or 
ferroso-ferric hydrate (Fe38HO = Fe2HO,Fe2f>HO), is pro- 
duced. 
Fe,3S04 + FeS04 + 8NaHO = Fes8HO + 4Na2S04 
Ferric 
sulphate. 
It is so readily attracted by a magnet, even when moist, as to 
collect round the poles when the instrument is immersed in 
the supernatant liquid. Hence the B. P. name, Ferri Oxidum 
Magnetic urn. 
Ferrous 
sulphate. 
Soda. 
Blk. Hydrate 
of iron. 
Sulphate 
of sodium. 
In this process the nitric acid oxidizes the hydrogen of the sul- 
phuric acid, the sulphuric radical uniting with the ferrous sulphate, 
the iron of which is at the same time altered from the ferrous to the 
ferric condition, ferric sulphate being formed. If too much nitric 
acid be employed, the second portion of ferrous sulphate will also 
be converted into ferric salt, and the solution, on the addition of 
alkali, yield only red ferric hydrate. This result may be avoided 
by evaporating the solution of ferric sulphate nearly to dryness, 
thus boiling off excess of nitric acid, or by pouring first the ferric 
and then the ferrous liquid into the alkali and thoroughly stirring 
the mixture; any nitric acid is then neutralized and rendered in- 
capable of oxidizing the ferrous sulphate subsequently added. 
Black hydrate of iron is decomposed by heat, yielding, in a closed 
vessel, oxyhydrates, and, finally, black oxide of iron or ferroso-ferric 
oxide. Heated in the air it absorbs oxygen and gives ferric oxide. 
The black forge-scales which collect near the blacksmith’s anvil 
have the composition of ferroso-ferric oxide: the black magma 
formed on exposing a mixture of iron and water to the air is fer- 
roso-ferric hydrate; but these varieties are apt to contain particles 
of metal, anil hence give hydrogen gas when dissolved in acids—a 
character which distinguishes them from the official preparation. 
If a dried specimen of the black hydrate of iron be required, the 
mixture should be well boiled and then set aside for an hour or two 
to favor aggregation of the particles, the mixture filtered, and the 
precipitate washed until the washings contain no trace of sulphate 
(that is, until they no longer yield a white precipitate with chloride 154 
THE METALLIC RADICALS. 
of barium). Black hydrate of iron absorbs oxygen even at the 
temperature of the water-bath ; it should consequently be dried at 
120°, a temperature at which only slight oxidation occurs. 
Pernitrate of Iron. Ferric Nitrate. 
Sixteenth Synthetical Reaction.—Place a few iron tacks in 
dilute nitric acid and set aside; solution of ferric nitrate, or 
pernitrate of iron, is formed (Fe26N03). 
Iron. 
Fe2 + 8HN03 = Fe26N03 + 4H20 + 2NO 
Nitric 
acid. 
Ferric 
nitrate. 
Water. 
Nitric 
oxide. 
Precipitate ferric hydrate from solution of ferric sulphate, 
wash, and dissolve it in nitric acid. 
Fe26HO + 6HN03 = Fe26N03 + GII20 
Ferric 
hydrate. 
Nitric 
acid. 
Ferric 
nitrate. 
Water, 
The latter is the official method for preparing Liquor Ferri Nitra- 
tis, U. S. P., definite quantities of solution of ferric sulphate and of 
nitric acid being employed. Sp. gr. 1.050. Strength, about 6 per 
cent, of anhydrous nitrate. 
Ferric nitrate and ferric acetate unite to form various aceto-nitrates, 
amongst which is one having the formula Fe24C2H302,N03,H0,4H20, 
crystallizing in hard, shining, brownish-red prisms. 
Seventeenth Synthetical Reaction.—Pass hydrogen gas (dried 
by passing over pieces of chloride of calcium contained in a 
Reduced Iron. 
Big. 32. 
tube, or through sulphuric acid in a wash-bottle) into a small 
quantity of ferric oxyhydrate or oxide (“ subcarbonate,” IJ. S. 
P.) contained in a tube arranged horizontally (a test-tube, the 
Preparation of Reduced Iron. IRON. 
155 
bottom of which has been accidentally broken, answers very 
well), the oxide being kept hot by a gas-flame; oxygen is re- 
moved from the oxide by the hydrogen, steam escapes at the 
open end of the tube, and after a short time, when moisture 
ceases to be evolved, metallic iron, in a minute state of division, 
remains. (See Fig. 32.) 
Fe,0:i + m, = Fe, + 3IT20 
Ferric 
oxide. 
Hydrogen. 
Iron. 
Water 
While still hot throw the iron out into the air; it takes fire 
and falls to the ground as oxide. 
If the ferric oxide is reduced in a gun-barrel heated by a strong 
furnace, the particles of iron aggregate to some extent, and, when 
cold, are only slowly oxidized in dry air. This latter form of re- 
duced iron is ler reduit or Quevenne's Iron, the ferri pulvis, or Fer- 
rum Reduction, U. S. P.—“a fine grayish-black powder, strongly 
attracted by the magnet, and exhibiting metallic streaks when rubbed 
with firm pressure in a mortar.” 
JSote I. The spontaneous ignition of the iron in the above experi- 
ment is an illustration of the influence of minute division on chemi- 
cal affinity. Ihe action is the same as occurs whenever iron rusts, 
and the heat evolved and amount of oxide formed is not greater 
from a given quantity of iron ; but the surface exposed to the action 
of the oxygen of the air is, in the case of this variety of reduced 
iron, so enormous compared with the weight of the iron, that heat 
cannot be conducted away sufficiently fast to prevent elevation of 
temperature to a point at which the whole becomes incandescent. 
In the slow rusting of iron escape of heat occurs, but is not ob- 
served, because spread over a length of time ; in the spontaneous 
ignition of reduced iron the whole is evolved at one moment. The 
mixture of lead and carbon (lead pyrophorus) resulting when tartrate 
of lead is heated in a test-tube until fumes cease to be evolved, spon- 
taneously ignites when thrown into the air, and for the same reason. 
Many substances, solid and liquid, if sufficiently finely divided and 
liable to oxidation, and especially if exposed in a warm place, be- 
come hot, and even occasionally spontaneously burst into flame. 
Oil on cotton-waste, powdered charcoal, coal, especially if pyritic 
or if very porous, or if powdered, resins in powder, and even flour, 
are familiar illustrations of materials liable to “ heat” or even burn 
spontaneously. 
Note IT.—The student having time and opportunity for the 
experiment is advised to make this seventeenth reaction a 
roughly quantitative one, by way of realizing what has been 
stated (see, again, the General Principles of Chemical Phil- 
osophy, pp. 36-59) respecting the action of chemical force on 
definite weights only of matter. Three tubes, similar to the 
oxide-tube shown in the engraving, should be prepared, the 156 
THE METALLIC RADICALS. 
second being connected to the first and the third to the second 
by India-rubber tubing in the usual manner. The first tube 
should contain pieces of chloride of calcium to absorb any 
traces of moisture not retained by the sulphuric acid. The 
second tube (the ends of the small tube being temporarily 
closed by small corks) should be weighed in any ordinary 
scales which will turn with a quarter or half of a grain, and, 
the weight being noted, 160 grains of dry ferric oxide should 
be neatly placed in the middle of the tube. (The oxide must 
be previously gently heated in a small crucible over a lamp to 
remove all traces of moisture.) The third tube should contain 
pieces of chloride of calcium to absorb the water produced in 
the reaction, and just before being connected should be weighed. 
The operation is now carried out. At its close, aud when the 
middle tube is cold, the latter tube and the third tube are again 
weighed. The oxide-tube should weigh 48 grains less than 
before, and the terminal tube 54 grains more than before. 
Fe.203 + SH2 = Fe, + 3H20 
112 + 48 = 160 6 112 54 
The operation is more quickly and easily performed if one-half 
or one-quarter of the weight of oxide be taken ; in that case 
one-half or one-quarter of the weight of iron and of water will 
be obtained. Indeed any weight of oxide may be employed ; 
the amount of iron and water resulting will be always exactly 
proportionate to the weights just mentioned. Thus 16 parts 
of oxide yield 11.2 of iron and 5.4 of water. Iron, hydrogen, 
and oxygen always combine in proportions of 56, 1, and 16 
respectively ; hence our justification for agreeing that the sym- 
bol Fe shall stand for 56, more exactly 55.9, parts by weight 
of iron, H for 1 part by weight of hydrogen, and 0 for 16 parts 
by weight of oxygen. 
Ferric Pyrophosphate. 
Eighteenth Synthetical Reaction.—To solution of pyrophos- 
phate of sodium add solution of ferric sulphate; a yellowish- 
white precipitate of ferric pyrophosphate (Fe43P207,9Hs0) 
separates. 
The official (U. S. P.) Ferri Pyrophosphas is to be made by 
adding 10 parts of pyrophosphate of sodium to an aqueous solu- 
tion of 9 parts of citrate of iron, evaporating and scaling. The 
apple-green product is a mixture of ferric pyrophosphate and 
citrate of sodium. IRON. 
157 
(&) Reactions having Analytical Interest (Tests'). 
(The iron occurring as a ferrous salt.) 
First Analytical Reaction.—Pass sulphuretted hydrogen (II2S) 
through a solution of a ferrous salt (e. </., ferrous sulphate) 
slightly acidulated by hydrochloric acid ; no precipitate occurs. 
This is a valuable negative fact, as will be evident presently. 
Second Analytical Reaction.—Add sulphydrate of ammo- 
nium (NUJIS) to solution of a ferrous salt; a black precipi- 
tate of ferrous sulphide (FeS) falls. 
FeS04 + 2 Am US = FeS + Am2S04 + II2S. 
Third Analytical Reaction.—Add solution of ferrocyanide of 
potassium (yellow prussiate of potash), K4Fe"CyB, or K4Fcy"", 
to solution of a ferrous salt; a precipitate (K2Fe"Fe"Cy6, or 
K2Fe"Fcy) falls, at first white, or bluish-gray, but rapidly be- 
coming blue, owing to absorption of oxygen. 
Fourth Analytical Reaction.—To solution of a ferrous salt 
add ferridcyanide of potassium (red prussiate of potash), 
KBFe'"2Cy12, or KBFdcy; a precipitate (Fe":iFe'"2Cy„>, or 
FV'3Fdcy) resembling Prussian blue (Turnbull’s blue) is 
thrown down. 
Other Analytical Reactions.—The precipitates produced from 
ferrous solutions on the addition of alkaline carbonates, phos- 
phates, and arseniates, as already described in the synthetical 
reactions of ferrous salts, are characteristic, and hence have a 
certain amount of analytical interest, but are inferior in this 
respect to the four reactions above mentioned. 
Note.—Alkalies (potash, soda, or ammonia) are incomplete 
precipitants of ferrous salts, hence are almost useless as tests, 
To solution of a ferrous salt add ammonia (NH4HO); on fil- 
tering off the whitish ferrous hydrate and testing the solution 
with sulphydrate of ammonium, iron will still be found. To 
another portion of the ferrous solution add a few drops of nitric 
acid and boil; this converts the ferrous into ferric salt, and 
now alkalies will wholly remove the iron, as already twice seen 
during-the performance of the synthetical experiments. 
In actual analysis, the separation of iron as ferric hydrate is an 
operation of frequent performance. This is always accomplished by 
the addition of alkali, and, if the iron occurs as a ferrous salt, by 
previous ebullition with a little nitric acid. Ferrocyanide and ferrid- 
cyanide of potassium are the reagents used in distinguishing ferrous 
from ferric salts. 
(The iron occurring as a ferric salt.) 
Fifth Analytical Reaction.—Through a ferric solution (fer- 158 
THE METALLIC RADICALS. 
ric chloride, e. g.) pass sulphuretted hydrogen ; a white precipi- 
tate of the sulphur of the sulphuretted hydrogen falls, and the 
ferric is reduced to a ferrous salt, the latter remaining in solu- 
tion. This reaction is of frequent occurrence in practical 
analysis. 
Sixth Analytical Reaction.—Add sulphydrate of ammo- 
nium to a ferric solution; the latter is reduced to the ferrous 
state, and black ferrous sulphide (FeS) is precipitated as in 
the second analytical reaction, sulphur being set free. 
Seventh Analytical Reaction.—To a ferric solution add ferro- 
cyanide of potassium (K4FeCy6, or K4Fcy"") ; a precipitate 
of Prussian blue, the common pigment, occurs (Fe",43Fe"Cy6, 
or Fe'"4Fcy""3). 
Evjhth Analytical Reaction.—To a ferric solution jadd solu- 
tion of ferrideyanide of potassium; no precipitate occurs, but 
the liquid is darkened to a brownish-red or to a greenish or 
olive hue if the salts are not quite pure. 
Ninth Analytical Reaction.—This is the production of a red 
precipitate of ferric hydrate, on the addition of alkalies to fer- 
ric salts, and is identical with the twelfth synthetical reaction. 
Note.—This reaction illustrates the conventional character of the 
terms synthesis and analysis. It is of equal importance to the 
manufacturer and the analyst, and is synthetical or analytical ac- 
cording to the intention with which it is performed. 
Other ferric reactions have occasional analytical interest. In 
neutral ferric solutions the tannic acid in aqueous infusion of 
galls occasions a bluish-black inky precipitate, the basis of most 
black writing inks. (The Mistura Ferri Aromatica of the 
British Pharmacopoeia, made by digesting metallic iron in an 
infusion of various vegetable substances, contains tannate, or 
rather tannates, of iron : it is commonly known in Ireland by 
the name of Heberden's Ink, after the physician by whom it 
was first used. It contains about 1 grain of iron in 1 pint.) 
Sulphoeyanide of Potassium (KCyS) causes the forma- 
tion of ferric sulphoeyanide, which is of a deep blood-red color. 
There is no ferric carbonate ; alkaline carbonates cause the 
precipitation of ferric hydrate, while carbonic acid gas escapes. 
Note.—Cyanogen (CN, or Cy/), ferrocyanogen (FeC6Nfi, or FeCyfi, 
or simply Fcy////), and ferrideyanogen (Fe.2Cy12, or Fdcyvl), are radi- 
cals which play the part of non-metallic elements, just as ammonium 
in its chemical relations resembles the metallic elements. They will 
be again referred to. 
Memorandum.—The reader must on no account omit to write 
2Fe2Cls + 2H2S = 4FeCl> + 4I4C1 + S2. ZINC, aluminium, iron. 
159 
out equations or diagrams expressive of each of the reactions 
of iron, analytical as well as synthetical. It is presumed that 
this has already been done immediately after each reaction has 
been performed. 
DIRECTIONS FOR APPLYING THE FOREGOING ANALYTICAL 
REACTIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION 
OF SALTS CONTAINING ONE OF THE METALS, ZlNC, 
Aluminium, Iron. 
Add solution of ammonia gradually : 
A dirty-green precipitate indicates iron in the state of a 
ferrous salt. 
A red precipitate indicates iron in the state of a ferric salt. 
A white precipitate, insoluble in excess, indicates the pres- 
ence of an aluminium salt. 
A white precipitate, soluble in excess, indicates zinc. 
These results may be confirmed by the application of some of the 
other tests to fresh portions of the solution. 
TABLE OF SHORT DIRECTIONS FOR APPLYING THE FOREGOING 
ANALYTICAL REACTION TO THE ANALYSIS OF AN AQUEOUS 
SOLUTION OF SALTS OF ONE, TWO, OK ALL THREE OF 
THE METALS, ZlNC, ALUMINIUM, IRON. 
7 -j 7 
Boil about half a test-tubeful of the solution with a few drops of 
nitric acid. This insures the conversion of ferrous into ferric salts, 
and enables the next reagent (ammonia) completely to precipitate 
the iron. Add excess of ammonia, and shake the mixture. Filter. 
Precipitate 
Al Fe* 
Dissolve in IIC1, add excess of K1IO, 
stir, filter. 
Filtrate 
Zn. 
Test by AmTIS 
(white ppt.). 
(red ppt.). 
Filtrate 
Al. 
Make slightly acid by HOI, 
and add excess of AmllOf 
(white ppt.). 
* The aluminium precipitate (Al26HO) is white, the iron (Fe26HO) 
red. If the precipitate is red, iron must be and aluminium may be 
present; if white, iron is absent, and further operations on the ppt. 
are unnecessary. This precipitate (Al26HO and Fe26HO) may also, 
if sufficient is at disposal, be analyzed by simply well shaking a 
washed portion in a tube with solution of potash or soda; the hydrate 
of iron is not thereby affected, while the hydrate of aluminium is dis- 
solved, and may be detected in the clear decanted fluid by neutralizing 
all alkali by a little excess of acid, and then adding excess of ammonia, 
f Alumina, when in small quantity, is sometimes prevented from 160 
THE METALLIC RADICALS. 
Note I.—If iron is present, portions of the original solution 
must be tested by ferridcyanide of potassium for ferrous, and 
by ferrocyanide for ferric salts; dark-blue precipitates with 
both indicate both salts. 
Note II.—If no ferrous salt is present, ebullition with nitric 
acid is unnecessary. It is, perhaps, therefore advisable always 
to determine this point by previously testing a little of the 
original solution with ferridcyanide; if no blue precipitate 
occurs, the nitric acid treatment may be omitted. 
The following Table (vide p. 161) is perhaps the best, but not the 
only, adaptation of the ordinary reactions to systematic analysis. In 
it the analytical scheme for the third group is added to that of the 
first two groups. As before, analysis is commenced by the addition 
of chloride of ammonium (NII4C1) to prevent partial precipitation 
of magnesium, and by ammonia (NIQIIO) to neutralize any acid. 
For acid destroys the group precipitant, sulphydrate of ammonium 
(NIQHS), preventing its useful action, and causing a precipitation 
of the free sulphur it commonly contains. Any precipitate by the 
ammonia may be disregarded, for the sulphydrate attacks both solid 
and liquid. 
Note—When a test gives no reaction, absence of the body sought 
for may lie fairly inferred. If a group-test (that is, a test which 
precipitates a group of substances) gives no reaction, the analyst 
is saved the trouble of looking for any of the members of that 
group. 
Chart for all Metals hitherto considered. 
207. Name the chief ores of iron. 
208. How is the metal obtained from the ores? 
209. What is the chemical difference between cast iron, wrought 
iron, and steel? 
210. Explain the process of welding. 
211. What is the nature of chalybeate waters? 
212. Illustrate by formula the difference between ferrous and ferric 
salts. 
213. Under what different circumstances may the atom of iron be 
considered to exert bivalent, trivalent, and sexivalent activity ? 
214. Write a paragraph on the nomenclature of iron salts. 
215. Give a diagram of the official process for the preparation of 
ferrous sulphate. 
216. In what respects do Sulphate of Iron, Granulated Sulphate 
of Iron, and dried Sulphate of Iron differ? 
QUESTIONS AND EXERCISES. 
being precipitated by ammonia through the presence of organic mat- 
ter derived from the filter-paper by action of the potash. In cases of 
doubt, therefore, before adding ammonia boil the liquid with a little 
nitric acid, which destroys any organic matter. CHART FOR METALS HITHERTO CONSIDERED. 
161 
TABLE OF SHORT DIRECTIONS FOR THE ANALYSIS OF AN AQUEOUS SOLUTION OF SALTS OF ANY OR ALL 
OF1 THE METALLIC ELEMENTS HITHERTO CONSIDERED. 
Add AmCl: AmllO ; AmllS ; stir, filter. 
Precipitate 
Fe A1 Zn. 
Wash, dissolve in IIC1,* boil (to remove II2S), 
filter (to remove S), add excess of IvHO,f 
stir, filter. 
Filtrate 
Ba Ca Mg Am Na K. 
Add Am2COs, boil, filter. 
ft 
(test orig. sol. 
by K tFcy 
and KeFdcy). 
Filtrate 
Al Zn. 
Neutralize with HC1. 
Add AmHO, stir, filter. 
Ppt. 
Ba Ca. 
Dissolve in HC2H302, 
Add K2Cr04, filter. 
Filtrate 
Mg Am Na K. 
Add Am2IIP04, stir, filter. 
Ppt. 
Al 
(white). 
Filtrate 
Zn. 
Add AmTIS 
(white ppt.}. 
Ppt. 
Ba 
(yellow). 
Filtrate 
Ca 
Add Am2C204 
(white ppt.). 
Ppt. 
Mg 
(white). 
Filtrate 
Am Na K. 
Evap., ignite, dissolve. 
Na by flame ; K by PtCl4; 
orig. sol. for Am. 
* Add, also, a few drops of IIN03 if Fe be present—i. e., if the ppt. be black. ( Vide notes on pp. 157 and 160.) 
f Or add excess of ammonia, filter, and test filtrate for zinc. The hydrates of iron and aluminium may then be sepa- 
rated by an alkali, as described in the foot-note to the previous table, p. 159. 162 
THE METALLIC RADICALS. 
217. How is ferrous sulphate obtained on the large scale? 
218. Mention the chemical names of white, green, and blue vitriol. 
219. Why does ferrous sulphate become brown by prolonged ex- 
posure to air? 
220. Give a diagram showing the formation of Ferrous Carbonate. 
221. Describe the action of atmospheric oxygen on ferrous carbo- 
nate. Can the effect be prevented ? 
222. In what order would you mix the ingredients of Mistura 
Ferri Composita, and why? 
223. Write out an equation illustrative of the formation of the 
Phosphate of Iron. 
224. Why is acetate of sodium used in the preparation of ferrous 
phosphate ? 
225. Which four compounds of iron may be formed by the direct 
union of their elements ? 
226. Give the official method for the preparation of Solution of 
Ferric Chloride. 
227. Of what use is the spirit in Tincture of Perehloride of Iron? 
228. How may Ferrous be converted into Ferric Sulphate? 
229. What is the formula of Ferric Acetate? And how is it pre- 
pared for use in pharmacy ? 
230. Express by formulae the difference between Ferri Peroxidum 
Humidum, B. P., and Ferri Peroxidum Hydraium, B. P. 
231. How does Ferric Hydrate act as an antidote to arsenic? 
232. What are the properties of anhydrous ferric oxide ? 
233. What are the general characters and mode of production of 
the medicinal scale preparations of iron ? 
234. In what state is the iron in Vinum Ferri Am arum, U. S. P.? 
235. What other form of Wine of Iron is official? 
236. Give equations illustrating the chief steps in the artificial 
production of the so-called Magnetic Oxide of Iron. 
237. How is precipitated magnetic oxide of iron distinguished 
from the varieties made directly from the metal? 
238. Why is magnetic oxide of iron officially directed to be dried 
at a temperature not exceeding 120° Fahr? 
239. Give a diagram showing the formation of Ferric Nitrate. 
240. Work out a sum showing how much anhydrous ferric oxide 
will yield, theoretically, one hundred-weight of iron. Ans. 160 lbs. 
241. What are the properties of anhydrous ferric oxide? 
242. Give the characteristic tests for iron, distinguishing between 
ferrous and ferric reactions, and illustrating each by an equation or 
a diagram:— 
a. Sulphydrate of ammonium. 
b. Ferrocyanide of potassium. 
c. Ferridcyanide of potassium. 
d. Caustic alkalies. 
e. Sulphocyanide of potassium. 
243. Describe the action of ammonia on salts of iron, aluminium, 
and zinc respectively. 
244. What precautions must be used in testing for calcium a solu- 
tion containing iron ? ARSEXICUM. 
163 
245. How is magnesium detected in the presence of zinc ? 
246. How is aluminium detected in the presence of magnesium? 
247. Draw up a scheme for the analysis of an aqueous liquid con- 
taining salts of iron, barium, and potassium. 
248. How may zinc, magnesium, and ammonium be consecutively 
removed from aqueous solution ? 
ARSENICUM, ANTIMONY. 
These elements resemble metals in appearance and in the character 
of some of their compounds; but they are still more closely allied to 
the non-metals, especially to phosphorus and nitrogen. Their atoms 
are quinquivalent (Asv, Sbv), as seen in arsenic anhydride (As205) 
and pentachloride of antimony (SbCl5), but usually exert trivalent 
activity only (As111, Sbm), as seen in the hydrogen and other com- 
pounds (AsII3, AsC13, AsBr3, Asl3). A few preparations of these 
elements are used in medicine; but all are more or less powerful 
poisons, and hence have considerable toxicological interest. The 
iodide (Arsenti Iodidum, U. S. P.) may be made by cautiously fusing 
together atomic proportions of arsenieum and iodine. It is an 
orange-red crystalline solid, soluble in water. The Liquor Arsenti 
et Hydrargyri Iodidi, U. S. P., or “ Donovan s Solution, is made by 
dissolving iodide of arsenieum and red iodide of mercury in water, 
in the proportion of 1 per cent, of each. The old Donovan s Solu- 
tion contained in each fluidounce (wine measure) the equivalents of 
1 grain of white arsenic (As203), 2 grains of peroxide of mercury, 
and about 7 grains of iodine. 
Arsenicum is an exception to the rule that the atomic weights 
(taken in grains, grammes, or other weight) of elements, under sim- 
ilar circumstances of temperature and pressure, give equal volumes 
of vapor, the equivalent weight (75) of arsenieum only occupying 
half such a volume. Hence, while the molecular weights (that is, 
double the atomic weights of oxygen (02 — 32), hydrogen (H3==2), 
nitrogen (N2 = 28), etc.) give a similar bulk of vapor at any given 
temperature and pressure, the double atomic weight of arsenieum 
(As2=150), at the same temperature and pressure, only affords half 
this bulk. It would appear, therefore, that the molecule of arsenieum 
contains four atoms, and that its formula is As4. As in the case of 
sulphur, however, arsenieum, in the state ordinarily known to us, 
may be abnormal, and a variety yet be found in which the molecular 
weight is double (instead of quadruple) the atomic weight. 
From observed analogy between the two metals, the molecular 
constitution of antimony is probably similar to that of arsenieum. 
ARSENICUM. 
Sources.—Arsenical ores are frequently met with in nature, the 
commonest being the arsenio-sulphide of iron (FeSAs). This mine- 
Symbol As. Atomic weight 74.9. 164 
THE METALLIC RADICALS. 
ral is roasted in a current of air, the oxygen of which, combining with 
the arsenicum, forms common white arsenic (As203, possibly As4Ofi) 
(Acidum Arseniosum, U. S. P.), or arsenious oxide, which is con- 
densed in chambers or long flues. It commonly “ occurs as a heavy 
white powder, or in sublimed masses, which usually present a strat- 
ified appearance, caused by the existence of separate layers, differ- 
ing from each other in degrees of opacity.” The vitreous or amor- 
phous arsenic is far more soluble than the crystalline variety, and 
in other respects they differ in properties. Such differences between 
the crystalline and amorphous varieties of an element or compound 
are not unfrequent: they have not yet been satisfactorily explained. 
Realgar (red algar) is the red native sulphide (As2S2), and orpiment 
(iauripigmentum, the golden pigment) the yellow native sulphide 
(As2S3) of arsenicum. The iodide of arsenicum (Asl3) may be made 
from its elements or (Babcock) by dissolving white arsenic in aqueous 
hydriodic acid and evaporating. 
Reactions having (a) Synthetical and (h) Analytical 
Interest. 
(a) Reactions having Synthetical Interest. 
First Sj/nthetical Reaction.—Boil a grain or two of powdered 
arsenic (As203) in water containing an equal weight of bicar- 
bonate of potassium, and, if necessary, filter. The solution, 
colored with compound tincture of lavender, and containing 1 
per cent, of arsenic, forms the Liquor Potassii Arsenitis, 
U. S. P. (Fowler s Solution). 
Note.—This official solution does not generally contain arsenite of 
potassium; for the arsenic does not decompose the carbonate of potas- 
sium, or only after long boiling. From concentrated solutions car- 
bonic acid gas is more quickly eliminated. 
Alkaline Solution of Arsenic. 
Arsenious Acids and other Arsenites. 
Arsenic or arsenious anhydride (the so-called arsenious acid), 
when dissolved in water, is said to yield true arsenious acid (1I3As03) 
—the arsenite of hydrogen. 
Arsenious 
anhydride. 
As203 + 3TI20 = 2H3 A s03 
Water. 
Arsenious 
acid. 
"When arsenic (As203) is dissolved in excess of solutions of potash 
or soda, arsenites are formed having the formulae KH2AsU3 and 
NalLjAsOj. Boiled with excess of arsenic, one molecule of these 
salts combines with one of arsenic. The usual character of such 
compounds is that of oily alkaline liquids. Arsenic fused with alka- 
line carbonates yields pyroarseniates (Na4As207 or H4As207) and 
metallic arsenicum. Arsenites have the general formula K/.iAs0.j. ARSENICUM. 
Acid Solution of Arsenic 
Second Synthetical Reaction.—Boil arsenic with dilute hydro- 
chloric acid. Such a solution made with prescribed propor- 
tions of acid (2 per cent.) and water, and containing 1 per 
cent of arsenic (As2()3), forms the Liquor Aculi Arseniosi, 
IT. S. P. (De Valangins Solution contained a grain and a 
half per ounce.) 
Note.—No decomposition occurs in this experiment. The liquid 
is simply a solution of arsenic in dilute hydrochloric acid. These 
two solutions may be preserved for analytical operations. 
Mem.—The practical student should boil arsenic in water also, 
and thus have an acid, alkaline, and aqueous solution for analytical 
comparison. 
Arsenicum. 
Third Synthetical Reaction.—Place a grain or less of arsenic 
at the bottom of a narrow test-tube, cover it with about half 
an inch or an inch of small fragments of dry charcoal, and hold 
the tube, nearly horizontally, in a flame, the mouth being 
loosely covered by the thumb. At first let the bottom of the 
tube project slightly beyond the flame, so that the charcoal 
may become nearly red hot; then heat the bottom of the tube. 
The arsenic will sublime, become deoxidized by the charcoal, 
carbonic oxide being formed, and arsenicum be deposited in 
the cooler part of the tube as a dark mirror-like incrustation. 
There is a characteristic odor, resembling garlic, emitted during 
this operation, probably due to a partially oxidized trace of arseni- 
cum, which escapes from the tube; for arsenic does not give this 
odor; moreover, arsenicum being a freely oxidizable element, its 
vaporous particles could scarcely exist in the air in an entirely 
unoxidized state. 
Metallic arsenicum may be obtained in large quantities by the 
above process if the operation be conducted in vessels of commen- 
surate size. But performed with great care, in narrow tubes, using 
not charcoal alone, but black flux ( a mixture of charcoal and car- 
bonate of potassium obtained by heating acid tartrate of potassium 
in a test-tube or other closed vessel till no more fumes are evolved), 
the reaction has considerable analytical interest, the garlic odor and 
the formation of the mirror-like ring being highly characteristic of 
arsenicum. Compounds of mercury and antimony, however, give 
sublimates which may be mistaken for arsenicum. 
Fourth Synthetical Reaction.—Boil a grain or two of arsenic 
with a few drops of nitric acid until red fumes cease to be 
evolved; evaporate the solution in a small dish to dryness, to 
Arsenic Acid and other Arseniates. TIIE METALLIC RADICALS. 
remove excess' of nitric acid ; dissolve the residue in water; 
the product is Arsen'ic acid (1I3As04). 
Arsenic acid, when strongly heated, loses the elements of water, 
and arsenic anhydride remains (As205). 
Arsenic anhydride readily absorbs water and becomes arsenic acid 
(H3As04). Arsenic acid is reduced to arsenious by the action of 
sulphurous acid H3As04 + H2S03 = H3As03 + H2S04. 
Salts analogous to arsenic acid, the arseniate of hydrogen, are 
termed arseniates, and have the general formula B/3As04. The am- 
monium arseniate (Am2IIAs04) may be made by neutralizing arsenic 
acid with ammonia. Its solution in water forms a useful reagent. 
Arsenic acid is used as an oxidizing agent in the manufacture 
of the well-known dye, magenta. 
Arsenite and arseniate of sodium are used in the cleansing opera- 
tions of the calico-printer. 
Pyroarseniate and Arseniate of Sodinm, 
Fifth Synthetical Reaction.—Fuse two or three grains of 
common white arsenic (As203) with nitrate of sodium (NaN03) 
and dried carbonate of sodium (Na2C03) in a porcelain cru- 
cible, and dissolve the mass in water; solution of arseniate of 
sodium (Na2IIAs04) results. 
Arsenic. 
As203 + 2XaX03 + X a2C03 = Xa4As2Or + N203 + C0.2 
Nitrate of 
sodium. 
Carbonate 
of sodium. 
Pyroarseniate 
of sodium. 
Nitrous 
anhydride. 
Carbonic 
acid gas. 
The official proportions (B. P.) are 10 of arsenic to 8 J of nitrate 
of sodium and of dried carbonate, each powdered, the whole well 
mixed, fused in a crucible at a red heat till effervescence ceases, and 
the liquid poured out on a slab. The product is pyroarseniate of 
sodium (Na4As207). Dissolved in water, crystallized and dried, the 
salt has the formula Na2IIAs04,7H20 (Sodii Arsenias, U. S. P.). 
Na4As207 + 15H„0 = 2(Na2HAs04,7H20). 
Heated to 300° F. the crystals lose all water. A solution of 1 part 
of the anhydrous salt (Xa.JIAsO,) in 99 of water forms the Liquor 
Sodii Arseniatis, U. S. P. The anhydrous salt is used in this 
preparation because the crystallized is of somewhat uncertain 
composition. The fresh crystals are represented by the formula 
Xa2IIAs04, 12II20 (=53.7 per cent, of water); these soon effloresce 
and yield a stable salt having the formula Xa.,HAs04,7H20 (=40.4 
per cent, of water). To avoid the possible employment of a mix- 
ture of these bodies, the invariable anhydrous salt is officially used, 
constancy in the strength of a powerful preparation being thereby 
secured. 
The student will find useful practice in verifying the above num- 
bers representing the centesimal proportion of water in the two 
arseniates of sodium. This will readily be accomplished if what 
has already been stated respecting a symbol representing a number ARSENICUM. 
167 
as well as a name, and the remarks concerning a molecular weight, 
be remembered. 
The shape of each of the two varieties of arseniate of sodium 
(Na2lIAs04,12II20, and Na2HAs04,7H20) is identical with that 
of the corresponding phosphate of sodium (Na2HP04,12II20, and 
Na2HP04,7H20); the structure of the molecule of the 12-arseniate 
is the same as that of the 12-phosphate, and the 7-arseniate as that 
of the 7-phosphate; the two former are isomorphous, the two latter 
are isomorphous. This is only one instance of the strong analogy 
of arsenicum and its compounds with phosphorus and its corre- 
sponding compounds. The preparation and characters of the next 
substance, arseniate of iron, will remind the learner of phosphate 
of iron. 
Sixth Synthetical Reaction.—To solution of arseniate of 
sodium add a little acetate of sodium and then solution of 
ferrous sulphate; a precipitate of ferrous arseniate occurs 
(Fe32As04) (Fern Arsenias, B. P.). On the large scale 4 
parts of dried arseniate and 3 of acetate dissolved in 40 of 
water, mixed with 9 of sulphate in 60 of water, may be em- 
ployed. The precipitate should be collected on a calico filter, 
washed, squeezed, and dried at a low temperature (100° F.) 
over a water-bath to avoid excessive oxidation. 
Arseniate of Iron. Ferrous Arseniate, 
2Na2HAs04 + 2NaC2H:j02 + 3FeS04 = Fe32As04 
Arseniate of 
sodium. 
Acetate of 
sodium. 
Ferrous 
sulphate. 
Ferrous 
arseniate. 
+ 3Na2S04 + 2IKUTA 
Sulphate of 
sodium. 
Acetic acid. 
The use of the acetate of sodium is to insure the absence of free 
sulphuric acid in solution, sulphate of sodium being formed together 
with acetic acid. Sulphuric acid is a solvent of ferrous arseniate ; 
acetic acid is not. It is impossible to prevent the separation of sul- 
phuric acid, if only ferrous sulphate and arseniate of sodium be 
employed. At the instant of precipitation ferrous arseniate is 
white, but rapidly becomes of a green or greenish-blue color, owing 
to absorption of oxygen and formation of a ferroso-ferric arseniate. 
It is a tasteless, amorphous powder, soluble in acids. 
The Hydride and Sulphides of Arsenicum, and the Arsenites 
and Avseniates of Copper and of Silver, are mentioned in the 
following analytical paragraphs :— 
(6) Reactions having Analytical Interest ( Tests'). 
First Analytical Reaction.—Repeat the third synthetical re- 
action, operating on not more arsenic than lias about the bulk 
of a small pin’s head, and using not charcoal alone, but the 168 
THE METALLIC RADICALS. 
b/ack Jinx already mentioned (p. 105), or a well-made and per- 
fectly dry mixture of charcoal and carbonate of potassium ob- 
tained by heating the bicarbonate of potassium. The tube 
employed should be a narrow test-tube, or, better, a tube 
(easily made from glass tubing) having the following (Ber- 
zelius’s) form :— 
Fig. 33. 
The arsenic and black flux are placed in the bulb of the tube, 
which is then heated in a flame; the arsenicum condenses on 
the constricted portion of the tube. If now the bulb be care- 
fully fused off in a flame, the arsenicum may be chased up and 
down the narrower part of the tube until the air in the tube 
has reoxidized it to arseuious anhydride. 
If the operation has been performed in a less delicate manner 
in an ordinary test-tube, cut or break off portions of the tube 
containing the sublimate of arsenicum, put them into a test- 
tube and heat the bottom of the latter, holding it nearly hori- 
zontally, and partially covering the mouth with the finger or 
thumb; the arsenicum (As4) will absorb oxygen from the air 
in the tube, and the resulting arsenious anhydride (As.2Og) be 
deposited on the cool part of the tube in brilliant transparent, 
generally imperfect, octahedral crystals. 
Microscopic Test.—Prove that the crystals are identical in 
form with those of common white arsenic, by heating a grain 
Fig. 34. 
Fig. 34a. 
A sublimate of White Arsenic. (Magnified.) 
A perfect Octahedron. 
or less of the latter in another test-tube, examining the two 
sublimates by a good lens or compound microscope. 
The appearance of a sublimate of arsenic is peculiar and ARSENICUM. 
169 
quite characteristic. The primary form of each crystal is an 
octahedron (o’xreo, olefo, eight; idpa, hedra, side) (fig. 34a), or, 
rarely, a tetrahedron, and in a sublimate a few perfect octa- 
hedra are generally present. Usually, however, the crystals 
are modifications of octahedra, such as are shown in fig. 34—■ 
which is drawn from actual sublimates. 
Second Analytical Reaction.—Place a thin piece of copper, 
about a quarter inch wTide and half inch long, in a solution of 
arsenic, acidified by hydrochloric acid, and boil (nitric acid 
must not be present, or the copper itself will be dissolved) ; 
arsenicum is deposited on the plate in a metallic condition, an 
equivalent portion of copper going into solution. Pour off’ the 
supernatant liquid from the copper, wash the latter once or 
twice with water, dry the piece of metal by holding in the 
fingers and passing through a flame, and finally place it at the 
bottom of a clean dry narrow test-tube or a Berzelius tube; 
sublime as described in the last reaction, again noticing the 
form of the resulting crystals. 
This is commonly known as Reinsch’s test of arsenicum. The 
tube may be reserved for subsequent comparison with an antimonial 
sublimate (p. 185). 
Note.—Copper itself frequently contains arsenicum, a fact that 
may not, perhaps, much trouble an operator so long as he is per- 
forming experiments in practical chemistry merely for educational 
purposes; but wdien he engages in the analysis of bodies of un- 
known composition, he must assure himself that neither his appa- 
ratus nor materials already contain the element for which he is in 
search. 
The detection of arsenicum in metallic copper is best accomplished 
by distilling a mixture of a few grains of the sample with five or six 
times its weight of ferric hydrate or chloride (free from arsenicum) 
and excess of hydrochloric acid. The arsenicum is thus volatilized 
in the form of chloride of arsenicum, and may be condensed in water 
and detected by sulphuretted hydrogen (6th Analytical Reaction) or 
Reinsch’s test. The ferric chloride solution is, if necessary, freed 
from any trace of arsenicum by evaporating once or tw ice to dryness 
with excess of hydrochloric acid. 
Third Analytical Reaction : The hydrogen test, or “ Marsh's" 
test.—Generate hydrogen in the usual way from water by zinc 
and sulphuric acid, a bottle of about four or six ounces capacity 
being used, and a funnel-tube and short delivery-tube passing 
through the cork in the usual manner (see following figure). 
Dry the escaping hydrogen (except in rough experiments, 
when it is unnecessary) by adapting to the delivery-tube, by a 
pierced cork, a short piece of wider tubing filled with frag- 
ments of chloride of calcium, a. To the opposite end of the 170 
THE METALLIC RADICALS. 
drying tube fit a piece of narrow tubing ten or twelve inches 
long, made of hard German glass, and having its aperture nar- 
rowed by drawing out in the flame of the blowpipe. When 
the hydrogen has been escaping for a sufficient number of 
minutes, and at such a rate as to warrant the operator in con- 
Fig. 35. 
The Hydrogen Test for Arsenicum. 
eluding that all the air originally existing in the bottle has 
been expelled, set light to the jet, and then pour eight or ten 
drops of the aqueous solution of arsenic, or three or four 
drops of the acid or alkaline solution of arsenic, previously 
prepared, into the funnel-tube, washing the liquid into the 
generating-bottle with a little water. The arsenic is at once 
reduced to the state of arsenicum, and the latter combines 
with some of the hydrogen to form hydride of arsenicum or 
arseniuretted hydrogen gas (AsH:t). Immediately hold a piece 
of earthenware or porcelain (the lid of a porcelain crucible, 5, 
if at hand) in the hydrogen jet at the extremity of the de- 
livery-tube ; a brown spot of arsenicum is deposited on the 
porcelain. Collect several of these spots, and retain them for 
future comparison with antimonial spots (p. 181). 
The separation of arsenicum in the flame is due to the decomposi- 
tion of the arseniuretted hydrogen by the heat of combustion. The 
cool porcelain at once condenses the arsenicum, and thus prevents 
its oxidation to white arsenic, which would otherwise take place at 
the outer edge of the flame. 
Hold a small beaker, c, or wide test-tube over the flame for 
a few minutes; a white film of arsenic (As203) will be slowly 
deposited, and may be further examined in contrast with a 
similar antimonial film (p. 181). 
During these experiments the effect produced hv the arsenical ARSENICUM. 
171 
vapors on the color of the hvdrogen-flame will have been noticed; 
they give it a dull livid tint. This is characteristic. 
Apply the flame of a gas-lamp to the middle of the hard 
delivery-tube, d; the arseniuretted hydrogen, as before, is de- 
composed by the heat, but the liberated arsenicum (As2) imme- 
diately condenses in the cool part of the tube beyond the flame, 
forming a dark metallic mirror. The tube may be removed and 
kept for comparison with the antimonial deposit. 
Note I.—Zinc, like copper, frequently itself contains arsenicum. 
When a specimen free from arsenicum is met with, it should be 
reserved for analytical experiments, or a quantity of guaranteed 
purity should be purchased of the chemical-apparatus maker. Sul- 
phuric acid is more easily obtained free from arsenic. 
Note II.—In delicate and important applications of Marsh’s test, 
magnesium may be substituted for zinc with safety, as arsenicum 
has not yet been, and is not likely to be, found in magnesium. 
Magnesium in rods is convenient for this purpose, and may be 
obtained from most dealers in chemicals. 
Note III.—Sulphuric acid, which is often used for drying gases 
decomposes arseniuretted hydrogen. Chloride of calcium is there 
fore the appropriate desiccating agent for this gas. 
Fourth Analytical Reaction: F/eitm aim’s test.—Generate 
hydrogen by heating in a test-tube to near the boiling-point a 
strong solution of caustic soda or potash and some pieces of 
zinc (or aluminium). 
(Zn + 2NaH0 =v H2 + Na2Zn04—zincate of sodium.) 
Add a drop of arsenical solution, and spread over the mouth 
of the tube a cap of filter-paper moistened with one drop of 
solution of nitrate of silver, Again heat the tube, taking 
care that the liquid itself shall not spirt up on to the cap. A 
plug of cotton-wool may even be placed in the mouth of the 
test-tube to prevent this spirting (Senier). The arsenic is re- 
duced to arsenicum, the latter uniting with the hydrogen as in 
Marsh’s test; and the arseniuretted hydrogen passing up 
through the cap reacts on the nitrate of silver, causing the 
production of a purplish-black spot. 
'VsHa + 3H20 + 6AgN03 = H3AsO. + 6IIN03 + 3Ag. 
Note I.—This reaction is particularly valuable, enabling the ana- 
lyst to quickly distinguish arsenicum in the presence of its sister 
element antimony, which, although it combines with the hydrogen 
evolved from dilute acid and zinc, does not combine with the hydro- 
gen evolved from solution of alkali and zinc, and therefore does not 
give the effect just described. 
Note II.—Aluminium answers as well as zinc for Fleitmann’s test 172 
THE METALLIC RADICALS. 
(Gatehouse), or magnesium may be used; or instead of zinc and 
alkali, weak sodium amalgam may be employed (Davy). 
Fifth Analytical Reaction.—To a solution of chloride of tin 
in strong hydrochloric acid add a very small quantity of any 
arsenical solution. Arsenicum then separates, especially on 
the application of heat, giving the mixture a yellowish and then 
brownish hue or grayish-brown turbidity, or even a sediment 
of gray-brown flocks, according to the amount present. Much 
water prevents the reaction, its presence, therefore, must be 
avoided as far as possible; indeed a liquid saturated by hy- 
drochloric acid gas gives best results. Arsenic in sulphuric or 
hydrochloric acid or in tartar emetic, etc., may be detected by 
this method. Nitrates, such as subnitrate of bismuth, must 
first be heated with sulphuric acid to remove the nitric radical 
before applying this reduction test for arsenicum. The stan- 
nous is converted to stannic salt during the reaction. 
Distinction between Arsenious and Arsenic combinations.—The 
above tests are those of arsenicum, whether existing in the arsen- 
ious or arsenic condition, though from the latter the element is not 
generally eliminated so quickly as from the former. Of the fol- 
lowing reactions, that with nitrate of silver at once distinguishes 
arsenious acid and other arsenites from arsenic acid and other 
arseniates. 
Mem.—The exact nature of all these analytical reactions will be 
more fully evident if traced out by diagrams or equations. 
Sixth Analytical Reaction.—Through an acidified solution 
of arsenic pass sulphuretted hydrogen ; a yellow precipitate of 
sulphide of arsenicum or arsenious sulphide (As2S3) quickly 
falls. Add an alkaline hydrate or sulphydrate to a portion of 
the precipitate; it readily dissolves. The precipitate conse- 
quently would not be obtained on passing sulphuretted hydro- 
gen through an alkaline solution of arsenic. To another por- 
tion of the precipitate, well drained, add strong hydrochloric 
acid; it is insoluble, unlike sulphide of antimony. Neither 
sulphide is soluble in the weak acid. 
Note I.—Cadmium also affords a yellow sulphide in an acid solu- 
tion by action of sulphuretted hydrogen, but this sulphide is insol- 
uble in alkaline liquids. Under certain circumstances, tin, too, 
yields a yellow sulphide; but tin is otherwise easily distinguished 
{vide Tin). 
Note II.—A trace of sulphide of arsenicum is sometimes met with 
in sulphur (distilled from arsenical pyrites). It may be detected by ARSENICUM. 
173 
digesting the sulphur in solution of ammonia, filtering, and evaporat- 
ing to dryness; a yellow residue of sulphide of arsenicum is obtained 
if that substance be present. 
Seventh Analytical Reaction.—Through an acidified solution 
of' arsenic acid, or any other arseniate, pass sulphuretted hy- 
drogen ; the arsenic compound is gradually reduced to the 
arsenious and a yellow precipitate of arsenious sulphide and 
sulphur (As2S3 4- S3) slowly falls, soluble in alkaline hydrates 
and sulphydrates. 
Chemical Analogy of Sulphur ancl Oxygen.—The solubility of ar- 
senious and arsenic sulphide in alkaline solutions is good evidence 
of the close chemical analogy between them and the corresponding 
oxygen compounds of arsenicum. The potassium arsenite and sulph- 
arsenite, arseniate and sulph-arseniate, have the composition repre- 
sented by the following formulae •— 
K3As03 K3As04 
K3AsS3 K3AsS4 ; 
and the corresponding ammonium and sodium salts have a similar 
composition •— 
6AmHS + As2S3 = 2Am3AsS3 + 3II..S 
6AmHS + As2S5 = 2Am3AsS4 + 3H2S. 
Eighth, Analytical Reaction.—To an aqueous solution of 
arsenic add two or three drops of solution of sulphate of cop- 
per, and then cautiously add diluted solution of ammonia, drop 
by drop, until a green precipitate is obtained. The production 
of this precipitate is characteristic of arsenicum. To a por- 
tion of the mixture add an acid ; the precipitate dissolves. To 
another portion add alkali: the precipitate dissolves. These 
two experiments show the advantage of testing a suspected 
arsenical solution by litmus-paper before applying this reaction ; 
if acid, cautiously adding alkali, if alkaline, adding acid, tilf 
neutrality is obtained. (Or a special copper reagent may be 
used; see a note to the Eleventh Analytical Reaction, .below). 
The precipitate is arsenite of copper (Cu//fIAs03) or Scheele'n 
Green. More or less pure, or mixed with acetate or, occasionally, 
carbonate of copper, it is very largely used as a pigment under 
many names, such as Brunswick Green and Schweinfurth Green, 
by painters, paper-stainers, and others. 
Ninth Analytical Reaction.—Apply the test just described 
to a solution of arsenic acid or other arseniate; a somewhat 
similar precipitate of arseniate of copper is obtained. 
Tenth Analytical Reaction .—Repeat the eighth reaction, 
substituting nitrate of silver for sulphate of copper; in this 174 
THE METALLIC RADICALS. 
case yellow arsenite of silver (Ag;iAs03) falls, also soluble in 
acids and alkalies. 
Eleventh Analytical Reaction.—Apply the test to a solution 
of arsenic acid or other arseniate ; a chocolate-colored precipi- 
tate of arseniate of silver (Ag:jAs04) falls. 
This reaction may be utilized for the detection of arsenic Avhen 
occurring in ores and other substances as ordered by the U. S. Phar- 
macopoeia in the case of Antimonii Sulphidum Purrftcatum; 
“ If 2 gm. of the salt be mixed and cautiously ignited, in a por- 
celain crucible, with X gm. of pure nitrate of sodium, and the fused 
mass boiled with 25 gm. of water, there will remain a residue which 
should be white, or nearly so, and not yellowish nor brownish (abs. 
of other metallic sulphides). On boiling the filtrate with an excess 
of nitric acid, until no more nitrous vapors are evolved, then dis- 
solving in it 0.1 gm. of nitrate of silver, filtering again, if neces- 
sary, and cautiously pouring a few drops of water of ammonia on 
top, not more than a white cloud, but no red nor reddish precipitate, 
should appear at the line of contact of the two liquids (abs. of more 
than traces of arsenic).” 
Copper and Silver Reagents for Arsenicum.—The last four reac- 
tions may be performed with increased delicacy and certainty of 
result if the copper and silver reagents be previously prepared in 
the following manner- To solution of pure sulphate of copper (about 
1 part in 20 of water) add ammonia until the blue precipitate at first 
formed is nearly but not quite redissolved; filter and preserve the 
liquid as an arsenicum reagent, labelling it solution of Ummonio-sul- 
phate of copper (B. P.). Treat solution of nitrate of silver (about 
1 part in 40) in the same way, and label it solution of ammonio- 
nitrate of silver (B. P.). The composition of these two salts will be 
referred to subsequently. 
Arsenious and Arsenic Compounds.—While many reagents may 
be used for the detection of arsenicum, only nitrate of silver, as 
already stated, will readily indicate in which state of oxidation the 
arsenicum exists ; for the two sulphides and the two copper precip- 
itates, though differing in composition, resemble each other in ap- 
pearance, whereas the two silver precipitates differ in color as well 
as in composition. 
Soluble arseniates also give insoluble arseniates with solutions of 
salts of barium, calcium, zinc, and some other metals. 
In group-testing, arsenicum, if existing as arsenic acid or other 
arseniate, is not readily affected by such tests as sulphuretted hydro- 
gen or even hydrogen itself. Hence, if its presence in that state is 
suspected, the liquid under analysis should be warmed with a little 
sulphurous acid or oxalic acid, and then tested with sulphuretted 
hydrogen. 
Antidote.—In cases of poisoning by arsenic or arsenical prep- 
arations, the most effective antidote is recently precipitated 
moist ferric hydrate (Ferri Oxidum Hydra turn, U. S. P.). It 
is perhaps best administered in the form of a mixture or so- ARSENICUM. 
175 
lution of ferric sulphate (Liquor Ferri TersnlphatiU. S. P.) 
or perchloride of iron (Liquor or Tinctura) with carbonate of 
sodium—two or three ounces of the former to about one ounce 
of the crystals of the latter. Instead of the carbonate of so- 
dium, about a quarter of an ounce of calcined magnesia may 
be used. (See Ferri Oxidum Hydra turn cum Magnesia, U. S. 
P., page 148.) These quantities will render at least 10 grains 
of arsenic insoluble. Emetics should also be given, and the 
stomach-pump applied as quickly as possible. 
The above statements regarding the antidote for arsenic may be 
verified by mixing the various substances together, filtering, and 
proving the absence of arsenicum in the filtrate by applying some 
of the foregoing tests. 
Mode of Action of the Antidote.—The action of the carbonate of 
sodium or the magnesia is to precipitate ferric hydrate (Fe./dIO)— 
chloride of sodium (Nad) or magnesium (Mg0l2) being formed, 
which are harmless, if not beneficial, under the circumstances. 
The reaction between the ferric hydrate and the arsenic results in 
the formation of insoluble ferrous arseniate. 
2(Fe26H0) + As203 = Fe32As04 + 5H20 + Fe2H0 
Ferric 
hydrate. 
Arsenic. 
Ferrous 
arseuiate. 
Water. 
Ferrous 
liydrate. 
I he so-called Solution of Dialyzed Iron (see Index) is also, as 
might he expected from its composition, an antidote to arsenic. It 
should he administered with a little bicarbonate of either sodium or 
potassium, or with magnesia, or with any other salt which serves to 
neutralize arry acid that may be present. 
QUESTIONS AND EXERCISES. 
249. What is the formula of a molecule of arsenicum? 
250. In what form does arsenicum occur in nature? 
251. Describe the characters of white arsenic. 
252. Name the official preparations of arsenicum. 
253. What proportion of arsenic (As203) is contained in Liquor 
Potassii Arsenitis, U. S. P., and in Liquor Acidi Arseniosi, U. S. P. ? 
254. By what method may arsenic he reduced to arsenicum? 
255. Give the formulae of arsenious and arsenic acids and anhy- 
drides. ' 
256. Explain, by diagrams, the reactions which occur in convert- 
ing arsenic into Arseuiate of Sodium by the process of the British 
Pharmacopoeia. 
257. Why is anhydrous instead of crystallized arseniate of sodium 
employed in the preparation of Liquor Sodii Arseniatis, U. S. P. ? 
258. In the preparation of Arseniate of Iron from ferrous sulphate 
and arseniate of sodium, why is acetate of sodium included ? 176 
THE METALLIC RADICALS. 
259. Describe the manipulations necessary to obtain arsenic in its 
characteristic crystalline form. 
260. How is Reinsch’s test for arsenicuin applied, and under what 
circumstances may its indications be fallacious? 
261. Give the details of Marsh’s test for arsenicuin, and the pre- 
cautions to be observed in its performance. Explain the reactions 
by diagrams? 
262. What peculiar value has Fleitmann’s test for arsenicuin? 
263. Describe the conditions under which sulphuretted hydrogen 
becomes a trustworthy test for arsenicum ? 
264. How may a trace of sulphide of arsenicum be detected in 
sulphur ? 
265. How are the salts of copper and silver applied as reagents 
for the detection of arsenicum ? 
266. How are arsenites distinguished from arseniates ? 
267. Mention the best antidote in cases of poisoning by arsenic, 
explain the process by which it may be most quickly prepared, and 
describe its action. 
268. Do you know of any other antidote to arsenic? If so, de-- 
scribe the mode of administration. 
ANTIMONY. 
Symbol Sb (Stibium). Atomic weight 120. 
Sources and Uses.—Antimony occurs in nature chiefly as sulphide, 
Sb2S3. The crude or black antimony of pharmacy is this native sul- 
phide freed from impurities by fusion ; it has a striated, crystalline, 
lustrous fracture ; subsequently powdered it forms the grayish-black, 
crystalline Antimonii Sulphidum, U. S. P. When this powder is 
washed with solution of ammonia to remove any traces of sulphide 
of arsenicum and dried, it forms the Antimonii Sulphidum Purifica- 
tum, U. S. P. The metal is obtained from the sulphide by roasting, 
the resulting oxide being reduced with charcoal and carbonate of 
sodium. Metallic antimony is an important constituent of Type- 
metal, Britannia metal (tea and coffee pots, spoons, etc.), and the 
best varieties of Pewter. The old pocula emetica, or everlasting 
emetic cups, were made of antimony ; wine kept in them for a day 
or two acquired a variable amount of emetic quality. The metal is 
not used in making the antimonial preparations of the Pharmaco- 
poeia, the sulphide alone being, directly or indirectly, employed for 
this purpose. 
Antimony has very close chemical analogies with arsenicum. Its 
atom, in the common salts, exerts trivalent activity (e. g., SbCl3), 
but sometimes it is quinquivalent (e. g., SbCl5). 
Antimony, like arsenicum, unites with iodine to form a tri-iodide 
(Sbl3). A bromide (Sblir3) is also known. 177 
ANTIMONY. 
Reactions having (a) Synthetical and (b) Analytical 
Interest. 
(a) Reactions having Synthetical Interest. 
Chloride of Antimony. Antimonious Chloride. 
First Synthetical Reaction.—Boil half an ounce or less of 
sulphide of antimony with four or five times its weight of 
hydrochloric acid in a dish in a fume-chamber or in the open 
air; sulphuretted hydrogen is evolved, and solution of chloride 
of antimony, SbCl3, is obtained. 
Sb,S3 + 6HC1 = 2SbCl3 + 3H2S 
This solution, cleared by subsidence, is what is commonly known 
as Butter of antimony (Liquor Antimonii Chloridi, B. P.). If pure 
sulphide has been used in its preparation, the liquid is nearly color- 
less ; but much of that met with in veterinary pharmacy is simply 
a by-product in the generation of sulphuretted hydrogen from native 
sulphide of antimony and hydrochloric acid, and is more or less 
brown from the presence of chloride of iron. It not unfrequently 
darkens in color on keeping; this is due to absorption of oxygen 
from the air and conversion of light-colored ferrous into dark-brown 
ferric chloride or oxychloride. 
True butter of antimony (SbCl3) is obtained on evaporating the 
above solution to a low bulk, and distilling the residue. The butter 
condenses (as a white crystalline semi-transparent mass in the neck 
of the retort) ; at the close of the operation it may be easily melted 
and run down in a bottle, which should be subsequently well stop- 
pered. 
Pentachloride of antimony (SbCl3), or antimonic chloride, is a 
fuming liquid, obtained on passing chlorine over the lower chloride. 
Sulphide of 
antimony. 
Hydrochloric 
acid. 
Chloride of 
antimony. 
Sulphuretted 
hydrogen. 
Oxychloride of Antimony. Antimonious Oxychloride. 
Second Synthetical Reaction.—Pour the solution of chloride 
of antimony produced in the last reaction into several ounces 
of water; a white precipitate of oxychloride of antimony 
(2SbCl3,5Sb203) falls, some chloride of antimony remaining in 
the supernatant acid liquid. 
is the old pulvis Algarothi, pulvis angdicus, or mercurius 
vitas. On standing under water it gradually becomes crystalline. 
12SbCl3 + 15H20 = 2SbCl3,5Sb203 + 30IIC1 
Chloride of 
antimony. 
Water. 
Oxychloride of 
antimony. 
Hydrochloric 
acid. 
Well wash the precipitate with water, by decantation (vide 
p. 108), and add solution of carbonate of sodium ; the chloride 
Oxide of Antimony. Antimonious Oxide. 178 
THE METALLIC RADICALS. 
remaining with the oxide is thus decomposed, and oxide of 
antimony (Sb203) alone remains. This is Antimonii Oxidum, 
U. S. P. It is of a light buff or grayish-white color, or quite 
white if absolutely free from iron, insoluble in water, soluble 
in hydrochloric acid, fusible at a low red heat. The moist 
oxide of antimony may be well washed and employed for the 
next reaction, or dried over a water-bath. At temperatures 
above 212° oxygen is absorbed, and other oxides of antimony 
formed. The presence of the latter is detected on boiling the 
powder in solution of acid tartrate of potassium, in which 
oxide of antimony (Sb203) is soluble, but antimonic anhydride 
(Sb205) and the double oxide or so-called antimonious anhydride 
(Sb408) are insoluble. 
2SbCl3,5Sb.A + 3Na2C03 = 6SbsO# + 6NaCl + 3CO, 
Oxychloride of 
antimony. 
Carbonate of 
sodium. 
Oxide of 
antimony. 
Chloride of 
sodium. 
Carbonic 
acid gas. 
The higher oxide of antimony (Sb205), termed antimonic oxide 
or anhydride, corresponding with arsenic anhydride, is obtained on 
decomposing the pentaohloride by water, or on boiling metallic anti- 
mony with nitric acid. The variety obtained from the chloride differs 
in saturating power from that obtained from the metal, and is termed 
inetantimonic (aura, meta, beyond). 
Tartar Emetic. 
Third Synthetical Reaction.—Mix the moist oxide of anti- 
mony obtained in the previous reaction with about an equal 
quantity of cream of tartar (6 of the latter to 5 of the dry 
oxide) and sufficient water to form a paste; set aside for a day 
to facilitate complete combination ; boil the product with water, 
and filter; the resulting liquid contains the double tartrate of 
antimony and potassium (KSbC4II407), potassio-tartrate of 
antimony, tartrated antimony, or tartar emetic (emetic, from 
e/iiu), emeo, I vomit; tartar, from Taprapix;, tartaros, see Index). 
2KHCJIA + Sb2Os = 2KSbC4IT407 + H,0 
Acid tartrate of 
potassium. 
Oxide of 
antimony. 
Tartar emetic. 
Water. 
On evaporation the salt is obtained in colorless transparent 
triangular-faced crystals of the above composition, with a mole- 
cule of water of crystallization, forming the Antimonii et Po- 
tasni Tartras, U. S. P., 2KSb0C4H406,H20. 
The formula for tartar emetic is apparently inconsistent with 
the general formula for tartrates (R'R'CAA*) ; this will be 
subsequently fully explained in connection with Tartaric Acid. 
The salt appears to be an oxytartrate (KSbC4H4060). 
Tartar emetic is soluble in water, and slightly so in proof- ANTIMONY 
179 
spirit. Dissolved in sherry wine it forms the official Vinum 
Antimonii, U. S. P. 
Sulphurated Antimony. Oxysulphide of Antimony. 
Fourth Synthetical Reaction.—Boil a few grains of sulphide 
of antimony with solution of soda in a test-tube, and filter (or 
larger quantities in larger vessels, 1 part of sulphide to 12 of 
soda, and 30 of water for 2 hours, frequently stirring, and 
occasionally replacing water lost by evaporation). Into the 
filtrate, before cool, stir diluted sulphuric acid until the liquid 
is slightly acid to test-paper; a brownish-red precipitate of 
oxysulphide of antimony, Antimonium Sulphuratum, U. S. P., 
falls; filter, wash, and dry over a water-bath. It is a mixture 
of sulphide of antimony (Sb2S3) with a small and variable 
amount of oxide (Sb203). The oxide results from the double 
decomposition of sulphide of antimony and soda. 
If a small quantity of sulphur be boiled with the sulphide 
of antimony in solution of soda, the precipitate on addition of 
sulphuric acid will have a much brighter color, chiefly on 
account of the presence of a higher sulphide having a yellow 
color (Sb2S5). 
These are some of the many varieties of mineral kermes, so called 
from their similarity in color to the insect kermes. Kermes is the 
name, now obsolete, of the Coccus Ilicis, a sort of cochineal insect, 
full of reddish juice, and used for dyeing from the earliest times. 
The color of the precipitate is affected by the temperature as well as 
state of dilution of the alkaline liquid when the acid is added. A\ hen 
the alkaline liquid is boiled, especially if long exposed to air, oxygen 
is absorbed by some of the antimony, whose sulphur uniting with 
the trisulphate forms a portion of the lighter yellow pentasulphide. 
Kermes mineral thus varies much in proportion of oxide and of penta- 
sulphide as well as in the physical condition of its trisulphide. 
Explanation of Process.—The sulphides and oxides of antimony, 
like those of arsenicum, react with the sulphides and oxides of cer- 
tain metals to form soluble salts (Na3febS3 and Na3SbO,). The for- 
mer is deposited in yellow tetrahedral crystals when such an alkaline 
solution is set aside to slowly cool. 
2Sb?S, + 6NaH0 - 2Na3SbS3 + Sb203 +3H20 
Sulphide of 
antimony. 
Sb.,03 + 6NaHO = 2Na3Sb03 + 3H20 
Soda. 
Sulpli-antimouite 
of sodium. 
Oxide of 
antimony 
Water. 
Oxide of 
antimony. 
Soda. 
Antimonite 
of sodium. 
Water. 
In the hot solutions of these salts sulphide and oxide of antimony 
are soluble, and are reprecipitated in an indefinite state of combina- 
tion, partially on cooling, or wholly on the addition of acid. The 
acid also decomposes the oxysalt with precipitation of oxide, and the 180 
THE METALLIC RADICALS. 
sulphur salt with precipitation of orange sulphide of antimony. 
The acid is added to the liquid before much oxysulphide has depos- 
ited (that is, before the solution is cool), in order to insure uniform- 
ity of product. 
2Na3SbS3 + 3II2S04 = 3Na2S04 + Sb,S3 -f 3TI.,S 
Sulph-antimonite 
of sodium. 
2Na3Sb03 + 3H2S04 = 3Na2S()4 + Sb203 + 31I20 
Sulphuric 
acid. 
Sulphate of 
sodium. 
Sulphide of 
autilnony. 
Sulphuretted 
hydrogen. 
Antimonite of 
sodium. 
Sulphuric 
@cid. 
Sulphate of 
sodium. 
Oxide of 
antimony. 
Water. 
The oxide and sulphide indicated in these equations, together with 
excess of sulphide of antimony originally dissolved by the alkaline 
liquid, are all precipitated when the acid is added, and form the Sul- 
phurated Antimony of the Pharmacopoeia, a reddish-brown powder, 
readily dissolved by caustic soda, also by hydrochloric acid, with the 
evolution of sulphuretted hydrogen and the separation of a little 
sulphur. Its antimony is detected by dissolving the powder in 
hydrochloric acid or in solution of acid tartrate of potassium, and 
passing sulphuretted hydrogen through the liquid, as described in 
the first analytical reaction. 
The previous four synthetical reactions illustrate the official pro- 
cesses for the respective substances. The solution of chloride of 
antimony is only used in the preparation of oxide; the oxide, be- 
sides its use in the preparation of tartar emetic, is mixed with twice 
its weight of phosphate of calcium (purified bone-earth) to form 
Pulvis Antimonialis, U. S. P., or “James's Powder.” 
The sulphides and hydride of antimony are incidentally mentioned 
in the following analytical paragraphs. 
First Analytical Reaction.—Through an acidified antimonial 
solution pass sulphuretted hydrogen ; an orange precipitate of 
amorphous sulphide of antimony falls. It has the same com- 
position as the crystalline black sulphide (Sb2S3), into which, 
indeed, when dried, it is quickly converted by heat. Like sul- 
phide of arsenicum, it is soluble in alkaline solutions. Collect 
a portion on a filter, and, when well drained, add strong hydro- 
chloric acid ; it dissolves—unlike sulphide of arsenicum. 
A higher sulphide of antimony (Sb2S5), corresponding to the 
higher sulphide of arsenicum, exists. It is formed on passing 
sulphuretted hydrogen through an acidified solution of the 
higher chloride (SbCl5), or on boiling black sulphide of anti- 
mony and sulphur with an alkali, and decomposing the result- 
ing filtered liquid by an acid. 
Note.—The arsenious and antimonious compounds are those chiefly 
employed in medicine; arseniates of sodium and iron are, however, 
(hi) Reaction having Analytical Interest (Tests). ANTIMONY. 
181 
sometimes employed. The arseniates and rarely an antiinoniate are 
useful in analysis, and the antimonic chloride in chemical research. 
The higher compounds of both elements are noticed here chiefly to 
draw attention to the close analogy existing between arsenicum and 
antimony, an analogy carried out in the numerous other compounds 
of these elements. 
Second Analytical Reaction.—Dilute two or three drops of 
the solution of chloride of antimony with water; a precipitate 
of oxychloride occurs, the formation of which has been ex- 
plained under the similar synthetical reaction. The occurrence 
of this precipitate distinguishes antimony from arsenicum, but 
is a reaction that cannot be fully relied upon in analysis, be- 
cause requiring the presence of too much material and the ob- 
servance of too many conditions. Add a sufficient quantity of 
hydrochloric acid to dissolve the precipitate, and boil a piece 
of copper in the solution, as directed in the corresponding test 
for arsenicum (vide page 169); antimony is deposited on the 
copper. Wash, dry, and heat the copper in a test-tube as be- 
fore; the antimony, like the arsenicum, is volatilized off tlm 
copper and condenses on the side of the tube as white o :ide, 
hut the sublimate, from its low degree of volatility, condenses 
close to the copper ; moreover, it is destitute of crystalline cha- 
racter—that is to say, it is amorphous («, o, without; n»p<prh 
morph e, shape). 
Shake out the copper, and boil water in the tube for several 
minutes. Do the same with the arsenical sublimate similarly 
obtained. The deposit of arsenic slowly dissolves, and may be 
recognized in the solution by ammonio-nitrate of silver; the 
antimonial sublimate is insoluble. 
Third Analytical Reaction.—Perform the experiments de- 
scribed under Marsh’s test for arsenicum (pp. 169, 170), care- 
fully observing all the details there mentioned, but using a few 
drops of solution of chloride of antimony or tartar emetic in- 
stead of the arsenical solution. Antimoniuretted hydrogen, or 
hydride of antimony (SbH3), is formed and decomposed in the 
same way as arseniuretted hydrogen. 
To one of the arsenicum spots on the porcelain lid (p. 170) 
add a drop of a solution of “ chloride of lime ” (bleaching- 
powder) ; it quickly dissolves. Do the same with an antimony 
spot; it is unaffected. 
Heat more quickly causes the volatilization of an arsenicum than 
an antimony spot; sulphydrate of ammonium more readily dissolves 
the antimony than the arsenicum. 
Boil water for several minutes in the beaker or wide test- 
tube containing the arsenious sublimate (page 170); it slowly 182 
THE METALLIC RADICALS. 
dissolves, and may he recognized in the solution by the yellow 
precipitate given on the addition of solution of ammonio-nitrate 
of silver. The antimonial sublimate, similarly treated, does 
not dissolve. 
Pass a slow current of sulphuretted hydrogen through the 
delivery-tube removed from the hydrogen-apparatus (page 170), 
and, when the air may be considered to have been expelled from 
the tube, gently heat that portion containing the deposit of 
arsenicum ; the latter will be converted into a yellow sublimate 
of sulphide of arsenicum. . Remove the tube from the sul- 
phuretted-hydrogen apparatus, and repeat the experiment with 
a similar antimony deposit; it is converted into orange sul- 
phide of antimony, which, moreover, owing to inferior vola- 
tility, condenses nearer to the flame than sulphide of ar- 
senicum. 
Pass dry hydrochloric acid gas through the two delivery- 
tubes. This is accomplished by adapting first one tube and 
then the other by a cork to the test-tube containing a few 
lumps of common salt, on which a little sulphuric acid is 
poured during the momentary removal of the cork. The sul- 
phide of antimony dissolves and disappears; the sulphide of 
arsenicum is unaffected. 
Thorough conception of the chemistry of arsenicum and antimony 
will be obtained on constructing equations or diagrams descriptive of 
each of the foregoing reactions. 
Antidote.—The introduction of poisonous doses of antimo- 
nials into the stomach is fortunately quickly followed by vom- 
iting. If vomiting has not occurred, or apparently to an in- 
sufficient extent, any form of tannic acid may be administered 
(infusion of tea, nutgalls, cinchona, oak-bark, or other astrin- 
gent solutions or tinctures), an insoluble tannate of antimony 
being formed, and absorption of the poison consequently some- 
what retarded. The stomach-pump must be applied as quickly 
as possible. 
Recently precipitated moist ferric hydrate is also, according 
to T. and H. Smith, a perfect absorbent of antimony from its 
solutions, the chemical actions being probably, they say, similar 
to that Avhich takes place between ferric hydrate and arsenious 
anhydride. It may be given in the form of a mixture of per- 
chloride of iron with either carbonate of sodium or magnesia. 
These statements may be verified by mixing together the various 
substances, filtering, and testing the filtrate for antimony in the 
usual manner. 183 
ARSENICUM AND ANTIMONY. 
Directions for applying the foregoing reactions to 
THE ANALYSIS OF AN AQUEOUS SOLUTION OF SALTS OF 
ONE OF THE ELEMENTS ARSENICUM AND ANTIMONY. 
Acidify the liquid with hydrochloric acid, and pass through 
it sulphuretted hydrogen— 
A yellow precipitate indicates arsenicum. 
An orange precipitate indicates antimony. 
The result may be confirmed by the application of other 
tests. 
Directions for applying the foregoing reactions to 
THE ANALYSIS OF AN AQUEOUS SOLUTION OF SALTS OF 
both Arsenicum and Antimony. 
Acidify a small portion of the liquid with hydrochloric acid, 
and pass through it sulphuretted hydrogen. 
Note I.—If the precipitate by sulphuretted hydrogen is unmis- 
takably orange, antimony may be put down as present, and arseni- 
cum only further sought by the application of Fleitmann’s test to 
the solution of the sulphide in aqua regia* freed from sulphur by 
boiling, or, better, to the original solution. 
Note II.—Sulphide of antimony is far less readily soluble than 
sulphide of arsenieum in solution of carbonate of ammonium. But 
this fact possesses limited analytical value; for the color of the sul- 
phides is already sufficient to distinguish the one from the other 
when they are unmixed; and when mixed, much sulphide of anti- 
mony will prevent a little sulphide of arsenieum from being dis- 
solved by the alkaline carbonate, while much sulphide of arsenieum 
will carry a little sulphide of antimony into the solution. When the 
proportions are, apparently, from the color of the precipitate, less 
wide, solution of carbonate of ammonium will be found useful in 
roughly separating the one sulphide from the other. On filtering 
and neutralizing the alkaline solution by an acid, the yellow' sulphide 
of arsenieum is reprecipitated. The orange sulphide of antimony 
will remain on the filter. 
Note III.—Solution of bisulphite of potassium is said by Wohler 
to be a good reagent for separating the sulphides of arsenieum 
and antimony, the former being soluble, the latter insoluble in 
the liquid. 
Note I\r.—Another reagent for separating the sulphides of arsen- 
ieum and antimony is strong hydrochloric acid. As little water as 
possible must be present. On boiling, the sulphide of antimony dis- 
solves, while the sulphide of arsenieum remains insoluble. The 
liquid slightly diluted, filtered, more wmter added, and sulphuretted 
* A qua regia is a mixture of fifteen parts hydrochloric and four parts 
nitric acid. It was so called from its property of dissolving gold, the 
“king” of metals. ' 184 
THE METALLIC RADICALS. 
hydrogen again transmitted, gives orange sulphide of antimony. 
The process should previously be tried on the precipitated mixed 
sulphides. The presence of arsenicum may be confirmed by the 
application of Fleitmann’s test to the original solution. 
Note V.—If the precipitate by sulphuretted hydrogen is unmis- 
takably yellow, arsenicum may be put down as present, and any 
antimony detected by the previous or one of the following two pro- 
cesses. These two processes are rather long, and require much 
care in their performance, but are useful, because a small quantity 
of antimony in much arsenicum, or vice versa, may be detected by 
their means. 
First Process.—Generate hydrogen and pass it through a 
small wash-bottle containing solution of acetate of lead, to free 
the gas from any trace of sulphuretted hydrogen it may pos- 
sess, and then through a dilute solution of nitrate of silver con- 
tained in a test-tube. When the apparatus is in good working 
order, pour into the generating-bottle the solution to be ex- 
amined, adding it gradually to prevent violent action. After 
the gas has been passing for five or ten minutes, examine the 
contents of the nitrate-of-silver tube; arsenicum, if present, 
will be found in the solution in the state of arsenious acid, 
As El) + 3II.20 + 6AgNOs = H3As03 + 6HN03 + 3Ag2; 
while antimony, if present, will be found in the black precipi- 
tate that has fallen, according to the following equation :— 
SbH3 + 3AgN03 = SbAga + 3IIN03. 
The arsenious radical may be detected in the clear, filtered, 
supernatant liquid, which still contains much nitrate of silver, 
by cautiously neutralizing with a very dilute solution of am- 
monia, or by adding a few drops of solution of ammonio-nitrate 
of silver, yellow arsenite of silver being produced. The anti- 
mony may be detected by washing the black precipitate, boil- 
ing it in an open dish with solution of tartaric acid, acidulating 
with hydrochloric acid, filtering, and passing sulphuretted hy- 
drogen through the solution—the orange sulphide of antimony 
being precipitated (Hofmann). 
Second Process.—Obtain the metallic deposit in the middle 
of the delivery-tube, as already described under Marsh’s test. 
Act on the deposit by sulphuretted hydrogen gas, and then by 
hydrochloric acid gas, as detailed in the third analytical reaction 
of antimony (p. 181). If both arsenicum and antimony are 
present, the deposit, after the action of sulphuretted hydrogen, 
will be found to be of two colors, the yellow sulphide of arseni- 
cum being usually further removed from the heated portion of 
the tube than the orange sulphide of antimony. Moreover, QUESTIONS AND EXERCISES. 
185 
subsequent action of hydrochloric acid gas causes disappear- 
ance of the antimonial deposit, which is converted into chloride 
of antimony and carried oft- in the stream of gas. 
The chief objection to this process is the liability of the operator 
mistaking sulphur, deposited from the sulphuretted hydrogen gas 
by heat, for sulphide of arsenicum. But the presence or absence 
of arsenicum is easily confirmed by applying Fleitmann’s test to the 
original solution, while the process is most useful for the detection 
of a small quantity of a salt of antimony when mixed with much 
of an arsenical compound. 
The laboratory student may now proceed to the analysis of aque- 
ous solution of salts of any of the metallic elements hitherto con- 
sidered. The method followed may be that for the separation of 
the previous three groups, sulphuretted hydrogen being first passed 
through the solution to throw out arsenicum and antimony. The 
whole scheme of analysis is given on the next page. Three or four 
solutions should be examined before proceeding to the last'group of 
metals. 
Learners who have no opportunity of working at practical anal- 
ysis will gain much knowledge by endeavoring not to remember, 
but to understand these methods of separating elements from each 
other in a solution containing several compounds. 
QUESTIONS AND EXERCISES 
269. What is the composition and source of the Black Antimony 
of pharmacy? 
270. In what alloys is metallic antimony a characteristic ingre- 
dient? 
271. What is the quantivalence of antimony as far as indicated 
by the formulae of the official preparations? 
272. By a diagram show how “ Butter of antimony” is prepared. 
273. Write out equations or diagrams expressive of the reactions 
which occur in converting chloride of antimony into oxide. 
274. W hat is the formula of Tartar Emetic? 
275. Explain the official process for the preparation of Oxysul- 
phide of Antimony (Antimonium Sulphuratum, U. S. P.) by aid of 
diagrams. 
276. Give a comparative statement of the tests for arsenicum and 
antimony. 
277. How is antimony detected in the presence of arsenicum? 
278. How may arsenicum and iron be distinguished analytically? 
279. Describe a method by which antimony, magnesium, and iron 
may be separated from each other. 
280. Draw out an analytical chart for the examination of an 
aqueous liquid containing salts of arsenicum, zinc, calcium, and 
ammonium. 186 
THE METALLIC RADICALS. 
TABLE OF SHORT DIRECTIONS FOR THE ANALYSIS OF AN AQUEOUS SOLUTION OF SALTS OF ANY OR ALL 
OF THE METALLIC ELEMENTS HITHERTO CONSIDERED. 
Acidify with IIC1, and pass II2S through the solution ; filter. 
Precipitate 
As Sb. 
Wash, separate by 
carbonate of ammo- 
nium, or by strong 
HC1; or dissolve in 
a few drops of hy- 
drochloric and ni- 
Filtrate 
Fe Al Zn Ba Ca Mg K 
Add AmllO ;* AmllS; stir, 
Na Am. 
filter. 
Precipitatef 
Fe Al Zn. 
Wash, dissolve in HC1, boil with 
HNOj (p. 157), add KIIO in 
excess,J stir, filter. 
Filtrate 
Ba Ca Mg K Na Am. 
Add Ain2C03, boil, filter. 
Precipitate 
Ba Ca. 
Dissolve in HC2H302, 
add K2Cr04, filter. 
Filtrate 
Mg K Na Am. 
Add Am2IIP04, shake, filter. 
trie acids, and ex- 
amine by Hof- 
mann’s method (p. 
Precipitate 
Fe. 
Examine orig. 
solution for 
Filtrate 
Al Zn. 
Neut. by IIC1, add 
AmTIO, stir, filter. 
184). 
Precipitate 
Filtrate 
Precipitate Filtrate 
ferrous or 
ferric state. 
Ppt. 1 Sol. 
Al. 1 Zn. 
Ba. 
Ca. 
Mg. Am Na K. 
(page 199). 
* It is not usually necessary here to add NH4C1 to keep Mg in solution, the HC1 with some of the NH4HO commonly 
giving sufficient NH4C1 for this purpose. 
f Much time may sometimes be saved by carefully remembering the color of the various hydrates and sulphides 
precipitated. Thus, if the AmllS precipitate is white, iron cannot be present, and AmHO, for A1 and Zn, may be at once 
added to the hydrochloric solution of the precipitate. The group-tests in this Table are H2S, AmHS, and Am2COs. 
X The pupil should vary the process sometimes, as described in the foot-notes on pages 159 and 161. The treatment 
of other groups should occasionally be varied. By remembering the reactions on which analytical processes are based 
a pupil may often devise modified processes, and thus frequently save time, avoid working in one groove only, and 
acquire broader chemical views. 187 
COPPER. 
These metals, like arsenicum and antimony, are precipitated from 
acidified solutions by sulphuretted hydrogen, in the form of sulphides; 
but the sulphides, unlike those of arsenicum and antimony, are in- 
soluble in alkalies. The atom of copper is usually bivalent, Cu"; 
mercury bivalent in the mercuric salts, Hg//, and univalent in the 
mercurous salts, Hg/; lead sometimes quadrivalent, Pb"", but gene- 
rally exerting only bivalent activity, Pb//; and silver univalent, Ag'. 
COPPER, MERCURY, LEAD, SILVER. 
COPPER. 
Symbol Cu. Atomic weight 63.2. 
Source.—The commonest ore of this metal is copper pyrites, a 
double sulphide of copper and iron, raised in Cornwall; Australia 
and Russia supply malachite, a mixed carbonate and hydrate ; much 
ore is also imported from South America. It is smelted in enor- 
mous quantities at Swansea, South Wales, a locality peculiarly 
fitted for the operation on account of its proximity to the coal-fields 
and its position as a sea-coast town—these advantages at all times 
insuring cheap fuel and freightage to the different metallurgical 
establishments. An economical method of smelting copper pyrites 
and other sulphides has recently been introduced by llollway. 
After the sulphide is once melted air is driven, not over, as usual, 
but through the mass ; the combustion of the sulphur then becomes 
self-supporting and is greatly accelerated. 
Alchemy.—The alchemists termed this metal Venus, perhaps on 
account of the beauty of its lustre, and gave it her symbol ?, a com- 
pound hieroglyphic also indicating a mixture of gold © and a certain 
hypothetical substance called acrimony ©, the corrosive nature of 
which was symbolized by the points of a Maltese cross. To this day 
the blue show-bottle in the shop-window of the pharmacist is occa- 
sionally ornamented by such a symbol, indicative, possibly, of the 
fact that the blue liquid in the vessel is a preparation of copper. 
Coinage.—The material of British copper coinage is now a bronze 
mixture composed, in 100 parts by weight, of 95 copper, 4 tin, and 
1 zinc, the same as in the copper coinage of France. The penny 
is coined at the rate of 48 pence in one pound avoirdupois, of 7000 
grains, or 453.6 grammes; the halfpenny at 80 in the pound avoir- 
dupois, and the farthing at 160. British bronze coins are a legal 
tender in payments to the amount of Is. 
Metallic Copper, U. S. P., occurs 11 in slender wire, or thin foil cut 
into strips.” 
Quanticalence.—Copper forms two classes of salts; in one the 
atom is bivalent (Cu"), in the other it exerts univalent activity 
(Cu./). The former are of primary importance, the latter being 
for the most part unstable ami wanting in technical interest. Their 
compounds are distinguished as cupric and cuprous; but those of 
the higher class only have general interest, and will be almost ex- 
clusively alluded to in the following paragraphs. Cuprous iodide 
(Cu.J,2) "will subsequently be referred to as a convenient form in 188 
THE METALLIC RADICALS. 
which to remove iodine from solution, while the formation of 
cuprous oxide (Cu,20), under given circumstances, will come under 
notice as an indicator of the presence of sugar in a liquid. 
Reactions having (a) Synthetical and (6) Analytical 
Interest. 
(a) Synthetical Reactions. 
The processes for the following salts include the only synthet- 
ical reactions having any medical or pharmaceutical interest: 
1, cupric oxide, the black oxide of copper, prepared by heating 
fragments of copper to low redness on a piece of earthenware in 
an open lire; 2, cupric sulphate, the common sulphate of cop- 
per, prepared by boiling black oxide and about an equal weight 
of sulphuric acid in water, filtering, and setting aside the solu- 
tion so that crystals may form on cooling; and 3, ammonio- 
sulphate of copper, for the preparation of which see p. 174; 
also p. 189. 
<X 4- 02 - 2CuO 
Copper. 
Oxygen. 
Cupric 
oxide. 
Cupric 
oxide. 
CuO + H,S04 = CuS04 + h.2o 
Sulphuric 
acid. 
Cupric 
sulphate. 
Water, 
Sulphate of Copper (Capri Sulphas, U. S. P.) (CuS04,5H20), blue 
vitriol, Milestone, or cupric sulphate, is the only copper salt of much 
importance in Pharmacy. It is a by-product in silver-refining 
(2Ag2S04 -j- Cu2 — 2CuS04 + 2Ag2). A little is also formed in roast- 
ing copper pyrites. In the latter case some sulphide of iron and the 
sulphide of copper are oxidized to sulphates; but the low red heat 
finally employed decomposes the sulphate of iron, while the sulphate 
of copper is unaffected; it is purified by crystallization from a hot 
aqueous solution, though frequently much sulphate of iron remains 
in the crystals. Sulphate of copper results on dissolving in diluted 
sulphuric acid the black oxide (CuO) obtained in annealing cop- 
per plates (see the foregoing equations); it may also be pre- 
pared by boiling copper with three times its weight of sulphuric 
acid (2H2S04 -(- Cu = CuS04 -)- S02 + 2H20), diluting, filtering, 
evaporating, and crystallizing. In this process a little black 
sulphide of copper is formed. 
Anhydrous Sulphate of Copper (CuS04) is a yellowish-white 
powder prepared by depriving the ordinary blue crystals of sulphate 
of copper of their water of crystallization by exposing them to a 
temperature of about 400° F. It is used in testing alcohol and 
similar spirituous liquids for water, becoming blue if the latter be 
present. 
Verdigris (from verde-gris, Sp. green-grav) is a Subacetate or 
Oxyacetate of Copper (B. P.) (Cu202C2H302), obtained by exposing 
alternate layers of copper and fermenting refuse grape-husks to the COPPER. 
189 
action of air. Digested with twice its weight of acetic acid and 
a little water, the mixture being evaporated to dryness and the 
residue dissolved in water, it forms a Solution of Acetate of Copper 
(0u2C2H3O2,H2O), from which deep-green prismatic crystals of the 
acetate (Capri Acetas, U. S. P.) may be obtained. 
The modes of forming cupiic sulphide, hydrate, oxide, ferrocyanide, 
and arsenite, as well as the precipitation of metallic coppei', are inci- 
dentally alluded to in the following analytical paragraphs. 
First. Analytical Reaction. — Pass sulphuretted hydrogen 
through an acidified solution of a copper salt (sulphate, for ex- 
ample) ; black cupric sulphide (CuS) falls. 
Second Analytical Reaction.—Add sulphydrate of ammonium 
to an aqueous copper solution; cupric sulphide is again pre- 
cipitated, insoluble in excess. 
(J>) Reactions having Analytical Interest ( Tests') 
Note.—Cupric sulphide is not altogether insoluble in sulphvdrate 
of ammonium if free ammonia or much ammoniacal salt be present; 
it is quite insoluble in the fixed alkaline sulphides. 
Third Analytical Reaction.—Immerse a piece of iron or 
steel, such as the point of a penknife or a piece of wire, in a 
few drops of a copper solution ; the copper is deposited, of cha- 
racteristic color, an equivalent quantity of iron passing into 
solution. 
By this reaction copper may he recovered on the larger scale from 
waste solutions, old hoop or other scrap iron being thrown into the 
liquors. 
Fourth Analytical Reaction.—Add ammonia to a cupric solu- 
tion ; cupric hydrate (Cu2HO) of a light-blue color is precipi- 
tated. Add excess of ammonia ; the precipitate is redissolved, 
forming a blue solution of ammonio-salt of copper, so deep in 
color as to render ammonia an exceedingly delicate test for this 
metal. 
An ammonio-sulphate of copper may be obtained in large crystals 
by adding strongest solution of ammonia to powdered sulphate of 
copper until the salt is dissolved, placing the liquid in a test-glass 
or cylinder, cautiously pouring in twice its volume of strong alcohol 
or methylated spirit, taking care that the liquids do not become 
mixed, tying over the vessel with bladder, and setting aside for 
some weeks in a cool place (Wittstein.) The constitution of am- 
monio-sulphate and other ammonio-salts of copper and correspond- 
ing salts of silver will be alluded to in connection with “white pre- 
cipitate,” the official “ ammoniated mercury.” 
Cuprum Ammoniatum is an ammonio-sulphate of copper pre- 
pared by rubbing together sulphate of copper and carbonate of am- 
monium until effervescence ceases, and drying the product. 190 
THE METALLIC RADICALS. 
Fifth Analytical Reaction.—Add solution of potash or soda 
to a cupric solution; cupric hydrate (Cu2HO) is precipitated, 
insoluble in excess. Boil the mixture in the test-tube; the 
hydrate is decomposed, losing the elements of water, and be- 
coming the black anhydrous oxide (CuO). 
Sixth Analytical Reaction.—Add solution of ferrocyanide of 
potassium (K4Fcy) to an aqueous cupric solution ; a reddish- 
brown precipitate of cupric ferrocyanide falls. This 
is an extremely delicate test for copper. 
Seventh Analytical Reaction.-—To a cupric solution add so- 
lution of arsenic, and cautiously neutralize with alkali; green 
cupric arsenite (CulIAsO.,) falls. 
Note.—This precipitate has been already mentioned under arsen- 
icum. An arsenicum salt is thus a test for copper as a copper salt 
is for arsenicum—a remark that may obviously be extended to most 
analytical reactions; for the body acted upon characteristically by 
a reagent is as good a test for the reagent as the reagent is for it; 
indeed it becomes a reagent when the other body is the object of 
search. Most copper salts color flame green, the chloride blue. 
Antidotes.—In cases of poisoning by compounds of copper, 
iron filings should be administered, the action of which has just 
been explained (see third analytical reaction). Ferrocyanide 
of potassium may also be given (see sixth analytical reaction). 
Albumen forms with copper a compound insoluble in water; 
hence raw eggs should be swallowed, vomiting being induced, 
or the stomach-pump applied as speedily as possible. 
281. What are the analytical relations of copper, mercury, lead, 
and silver to each other and to arsenicum and antimony ? 
282. Name the sources of copper. 
283. What proportion of copper is contained in English and 
French “copper” coins? 
284. Give diagrams showing how Sulphate of Copper is prepared 
on the small and large scales. 
285. Work out a sum showing how much Crystallized Sulphate of 
Copper may he made from 100 parts of sulphide.—Ans. 261 \ parts. 
286. HoW may Oxide of Copper be prepared ? 
287. Mention the formula of Verdigris. 
288. Name a good clinical test for copper. 
289. What is the analytical position of copper ? 
290. Mention the chief tests for copper. 
291. How may copper be separated from arsenicum? 
292. Why is finely divided iron an effective antidote in cases of 
poisoning by copper? 
QUESTIONS AND EXERCISES. MERCURY. 
191 
MERCURY, 
Molecular weight 199.7 (not double the atomic weight). 
Symbol Hg. Atomic weight 199.7. 
Source.—Mercury occurs in nature as sulphide (IlgS), forming 
the ore cinnabar (an Indian name expressive of something red), and 
is obtained from Spain, California, Eastern Hungary, China, Japan, 
and Peru. 
Preparation.—The metal is separated by roasting off the sulphur 
and then distilling, or, better, distilling with lime, which combines 
with and retains the sulphur. 
Properties.—Mercury (Hydrargyrum, U. S. P.) is a silver-white 
lustrous metal, liquid at common temperatures. It boils at 662° F., 
and at—40° F. solidifies to a malleable mass of octahedral crystals. 
When quite free from other metals it does not tarnish, its globules 
roll freely over a sheet of white paper without leaving any streak or 
losing their spherical form, and when boiled with strong solution of 
sodium hyposulphite it does not lose its lustre and does not acquire 
more than a slightly yellowish shade. 
Formula.—The formula of the mercury molecule is Ilg and not 
Hg2, because (at all events at the high temperature at which alone 
the weight of its vapor can be determined) two volumes, which if 
hydrogen would weigh two parts (II2) or oxygen thirty-two parts 
(02), in the case of mercury vapor weigh only two hundred parts 
(ilg); that is, only once the atomic weight, not twice. That 200, 
and not 100, is the atomic weight of mercury is shown by the fact 
that 200 is the minimum proportion relative to 1 of hydrogen in 
which mercury combines, and by its relations to heat. Still it is 
difficult to imagine an atom existing in the free state in nature; and 
the suggestion has been made that (as is proved to be the case with 
sulphur) mercury, as we know it, is in abnormal condition, and that 
if the weight of its vapor could be taken at a lower temperature, or 
under some other condition, its molecular weight might be found to 
be 400. Similar remarks may be made respecting zinc, the molec- 
ular weight of which, so far as we know, is identical with its atomic 
weight. 
Medicinal Compounds.—The compounds of mercury used in medi- 
cine are all obtained from the metal. The metal itself, rubbed with 
chalk and sugar of milk, or with confection of roses and powdered 
liquorice-root, or with lard and suet, until globules are not visible 
to the unaided eye, is often used in medicine. The preparations are: 
the Hydrargyrum cum Or eta. U. S. P., or “ Gray Powder;” Massa 
Hydrargyrij U. S. P., “ Blue Mass” or “ Blue Pilland Unguentum 
Hydrargyri, U. S. P., or “ Blue Ointment.” There are also a Com- 
pound Ointment, a Plaster of Mercury, a Plaster of Ammoniacum 
and Mercury, a Liniment, and a Suppository. Their therapeutic 
effects are probably due not to the large quantity of metallic mercury 
in them, but to the small quantities of black and red oxide which 
occur in them through the action of the oxygen of the air on the 
finely-divided metal. The proportion of oxide or oxides varies ac- 
cording to the age of the specimen. 192 
THE METALLIC RADICALS. 
All these medicinal preparations of metallic mercury are indefinite 
and unsatisfactory, and that through no fault of the pharmacist. 
They much need investigation by therapeutists. Here, as in many 
similar cases, if Medicine would first ascertain her own requirements 
and then make them known, her handmaid Pharmacy would be found 
quite capable of supplying them. 
Mercurous and Mercuric Compounds.—Mercury combines with 
other elements and radicals in two proportions; those compounds 
in which the other, acidulous, radicals are in the lesser amount 
are termed mercurous, the higher being mercuric. Thus, calomel 
(H gCl*) is mercurous chloride, while corrosive sublimate (IIgCl2) 
is mercuric chloride. In every pair of mercuric compounds the 
mercuric contains twice as much complementary radical, in propor- 
tion to the mercury, as the mercurous. 
Note on Nomenclature.—The remarks made concerning the two 
classes of iron salts, ferrous and ferric (p. 140), apply in the main to 
the two series of mercury salts. The latter are systematically dis- 
tinguished in most modern works by the terms mercurous and mer- 
curic. In the British and United States Pharmacopoeias, however, 
which include only a few in comparison with the whole number of 
mercury salts, older and more strongly contrasted names are em- 
ployed, thus:— 
Systematic names. Official names. 
Mercurous iodide Green iodide of mercury. 
Mercuric iodide Red iodide of mercury. 
Mercurous nitrate Not mentioned. 
Mercuric nitrate Nitrate of mercury. 
Mercurous sulphate .... Not mentioned. 
Mercuric sulphate Sulphate of mercury. 
Mercurous chloride .... Subchloride of mercury. 
Mercuric chloride Perchloride of mercury. 
Mercurous oxide Black oxide of mercury. 
Mercuric oxide Red oxide of mercury. 
Specific gravity.—Mercury is 13.6 times as heavy as water. 
Amalgams.—The compound formed in fusing metals together is 
usually termed an alloy {ad and ligo, to bind); but if mercury is a 
constituent, an amalgam (iid'Aciy/ia, malagma, from /ia?.daau, malasso, 
to soften, the presence of mercury lowering the melting-point of 
such a mixture). Most metals, even hydrogen, according to Leow, 
form amalgams. 
* The specific gravity of the vapor of calomel, and the fact that the 
salt is not decomposed at the temperature at which its specific gravity 
is taken, indicate that the formula of calomel is HgCl, and not 
Hg2Cl2. MERCURY 
193 
IIeactions having (a) Synthetical and (h) Analytical 
Interest. 
(a) Synthetical Reactions. 
First Synthetical Reaction.—Hub together a small quantity 
of mercury and iodine, controlling the rapidity of combination 
by adding, previously, and afterward occasionally, a few drops 
of spirit of wine, which, by evaporation, absorbs heat, and 
thus keeps down temperature. The product is either mercuric 
iodide, mercurous iodide, or a mixture of the two, as well as 
mercury or iodine if excess of either has been employed. If 
the two elements have been previously weighed in single atom- 
ic proportions, 200 of mercury to 127 of iodine (about 8 to 5, 
or 1 ounce of mercury to 278 grains of iodine), the mercurous 
or green (grayish-green) iodide results (Hgl) (Hydrargyri lo- 
didum Viride, U. S. P.); if in the proportion of one atom of 
mercury to two atoms of iodine (200 to twice 127, or about 4 
to 5), the mercuric or red iodide, Ilgl*, results, an iodide that 
is also official, but made in another way. (See page 194.) 
The green iodide should be made and dried (without heat) 
with as little exposure to light as possible. The product 
should be well washed with alcohol to remove mercuric iodide. 
The Two Iodides. 
Mercurous iodide is decomposed slowly by light, and quickly by 
heat, into mercuric iodide and mercury. Mercuric iodide occurring 
as an impurity in mercurous iodide may be detected by digesting in 
ether (in which mercurous iodide is insoluble), filtering and evap- 
orating to dryness; mercuric iodide remains. Mercuric iodide is 
stable,°and may be sublimed in scarlet crystals without decomposi- 
tion. (For details of the method by which a specimen of the crystals 
may be obtained, and the precautions to be observed, vide “ Corro- 
sive Sublimate,” p. 198.) * 
Relation of Mercuric Iodide to Light—In condensing, mercuric 
iodide is at first yellow, afterwards acquiring its characteristic scar- 
let color. This may be shown by smearing or rubbing a sheet of 
white paper with the red iodide, and then holding the sheet before a 
fire or over a flame for a few seconds. As soon as the paper becomes 
hot the red instantly changes to yellow, and the salt does not quickly 
reo-ain its red color, even when cold, if the paper is carefully handled. 
But if a mark be made across the sheet with anything at hand, or the 
salt be pressed or rubbed in any way, the portions touched immedi- 
ately return to the scarlet condition. According to. AV arrington, 
this change is consequent upon rhomboidal. crystals being converted 
into octahedra with a square base, and will serve as an excellent 
illustration of the influence of physical structure in causing color. 
The yellow modification so acts on the rays of white light shining on 
its particles as to absorb the violet and reflect the complementary 194 
THE METALLIC RADICALS. 
hue, the yellow, which, entering the eye of the observer, strikes his 
retina, and thus conveys to the brain the impression of yellowness; 
and the red modification, though actually the same chemical sub- 
stance, is sufficiently .different in the structure of its particles to 
absorb the green constituent of white light and reflect the comple- 
mentary ray, the red. 
Illustration of the Chemical late of Multiple Proportions (p. 48). 
—Applying the atomic theory to the above iodides, it will at once be 
apparent why mercury and iodine should combine in the proportion 
of 200 of mercury with either 127 or 254 of iodine, and not with any 
intermediate quantity. For it is part of that theory that masses are 
composed of atoms, and that atoms are indivisible; and that the 
weight of the atom of mercury is to that of iodine as 200 is to 127. 
Mercury and iodine can only combine, therefore, in atomic propor- 
tions, atom to atom (which is the same as 200 to 127), or one atom 
to two atoms (which is the same as 200 to 254). To attempt to com- 
bine them in any intermediate proportion would be useless; a mere 
mixture of the two iodides would result. A higher proportion of 
mercury than 200 to 127 of iodine gives but a mixture of mercurous 
iodide and mercury; a higher proportion of iodine than 254 to 200 
of mercury gives but a mixture of mercuric iodide and iodine. Or, 
for example, 200 grains of mercury, mixed with, say, 200 of iodine, 
would yield 139 grains of mercurous iodide and 261 grains of mer- 
curic iodide; for the 200 grains of mercury uniting with 127 grains 
of the iodine give, for the moment, 327 grains of mercurous iodide 
and 73 grains of iodine still free. The 73 grains of iodine will im- 
mediately unite with 188 grains of the mercurous iodide (for if 127 
of I require 327 of Ilgl to form IIgI2, 73 will require 188), and form 
261 grains of mercuric iodide, diminishing the 327 grains of mer- 
curous iodide to 139 grains. 
Preparation of Red Iodide of Mercury by precipitation.—To 
a few drops of a solution of a mercuric salt (corrosive subli- 
mate, for example), add solution of iodide of potassium, drop 
by drop; a precipitate of mercuric iodide, IIgI2, forms, and at 
first quickly redissolves, but is permanent when sufficient iodide 
of potassium has been added. Continue the addition of iodide 
of potassium; the precipitate is once more redissolved. 
HgCl2 + 2KI = Hgl2 + 2KC1 
Mercuric 
chloride. 
Iodide of 
potassium. 
Mercuric 
iodide. 
Cl)lori<le of 
potassium. 
Note.—When first precipitated, mercuric iodide is yellowish-red, 
hut soon changes to a beautiful scarlet. Its solubility either in solu- 
tion of the mercuric salt or in solution of iodide of potassium renders 
the detection of a small quantity of a mercuric salt by iodide of 
potassium, or a small quantity of an iodide by a mercuric solution, 
difficult, and hence lessens the value of the reaction as a test. But 
the reaction has synthetical interest, the method by precipitation 
being that adopted in the British and United States Pharmacopoeias 
(Hydrargyri Iodidum Rubrum, U. S. 1\). Mercuric iodide thus made MERCURY. 
195 
has the same composition as that prepared by direct combination of 
its elements. Equivalent proportions of the"two salts must be used 
in making the preparation (IIgCH2 — 271; 2KI — 332). About 4 
parts of corrosive sublimate are dissolved in 50 or 60 of water 
(warmth quickens solution), and 5 of iodide of potassium in 15 or 
20 of water, the solutions mixed, and the precipitate collected on a 
filter, drained, washed twice with distilled water, and dried on a 
plate over a water-bath. Mercuric nitrate, which is more soluble, 
and therefore somewhat more convenient for use on the large scale, 
may be used instead of the mercuric chloride. The mercury in mer- 
curic or mercurous iodide is set free and sublimes in globules on heat- 
ing either powder with dried carbonate of sodium in a test-tube ; the 
iodine may be detected by digesting with solution of soda, filtering, 
and to the solution of iodide of sodium thus formed adding starch 
paste and acidulating with nitrous acid, when blue iodide of starch 
results. Mercuric iodide is insoluble in water, slightly soluble in 
alcohol, tolerably soluble in ether. Precipitated red iodide of mer- 
cury mixed with white wax, lard, and oil, forms the Unguentum 
Hydrargyri Iodidi Rubri, B. P. 100 parts of a 5-per cent, solution 
of mercuric chloride with 367 parts of a 5-per cent, solution of iodide 
of potassium forms the “ Test Solution of Iodide of Mercury and 
Potassium,” U. S. P. 
Second. Synthetical Reaction.—Place a globule of mercury, 
about half the size of a pea, in a test-tube; add twenty or 
thirty drops of nitric acid; boil slowly until red fumes (nitric 
oxide, NO) no longer form ; set aside. On cooling, if a globule 
of mercury still remains in the tube, crystals of mercurous 
nitrate separate. These may be dissolved in water slightly 
acidulated by nitric acid. The solution may be retained for 
subsequent analytical operations. 
The Two Nitrates 
Hg3 + 4 UNO, = 3HgNOs + 2H20 4- NO. 
Third Synthetical Reaction.—Place mercury in excess of 
strong nitric acid, and warm the mixture; mercuric nitrate is 
formed, and will be deposited in crystals as the solution cools. 
Or. to crystals of mercurous nitrate add nitric acid and boil 
until red fumes cease to form. Retain the product for a sub- 
sequent experiment. 
It will be seen that when mercury and nitric acid are boiled 
together mercurous nitrate is formed if the mercury be in excess, 
while mercuric nitrate is produced if the acid preponderate. 
The mercuric nitrates vary somewhat in composition, according to 
the proportion, strength, and temperature of the acid used in their 
formation. A mercuric nitrate may be obtained having the formula 
Hg2NOs. 
11,2, + 8HNO, = 3(Hg2N03) + 2NO + 4II,20 
Mercury. 
Nitric 
acid. 
Mercuric 
nitrate. 
Nitric 
oxide. 
Water. 196 
THE METALLIC RADICALS. 
Mercuric Oxynitrates.—From the normal mercuric nitrate several 
oxynitrates may be obtained. Thus on merely evaporating a solu- 
tion of mercuric nitrate, and cooling, crystals having the formula 
Hg6036N03 are deposited. The latter, by washing with cold water, 
yield a yellow pulverulent oxynitrate, Hg6044N03: mixed with lard, 
this has sometimes been used as an ointment. Boiled in water, the 
yellow gives a brick-red oxynitrate, IIg,.032N03. 
The pharmacopoeial preparations of mercuric nitrate are Liquor 
Hydrargyri Nitratis, U. S. P., containing half its weight of mercu- 
ric nitrate and free acid, sp. gr. 2.100, and Unguentum Hydrargyri 
Nitratis, U. S. P. The former is made by placing 40 parts of red 
oxide of mercury in 45 parts of nitric acid diluted with 15 parts of 
water. 
HgO + 2IINO3 = IIg2N03 + II20. 
The Unguentum or “Citrine Ointment” is made by oxidizing lard 
oil with nitric acid, and then adding a solution of mercury in nitric 
acid. 
The Two Sulphates, 
Fourth Synthetical Reaction.—Boil two or three grains of 
mercury with a few drops of strong sulphuric acid in a test- 
tube, or, better, small dish; sulphurous acid gas (S02) is 
evolved, and mercuric sulphate (Hydrargyri Sulphas, B. P.) 
(HgS04) results—a white heavy crystalline powder. 
Hg + 2H2S04 = HgS04 + SO, + 2II20 
Mercury. 
Sulphuric 
acid. 
Mercuric 
sulphate. 
Sulphurous 
acid gas. 
Water, 
Between two and three ounces of mercuric sulphate may be 
prepared from a fluidraehm of mercury and a fluidounce of sul- 
phuric acid boiled together in a small dish. These ai’e the 
official proportions. The operation is completed and any ex- 
cess of acid removed by evaporating the mixture of metal and 
liquid to dryness, either in the open air or in a fume-chamber, 
sulphuric acid vapors being excessively irritating to the mucous 
membrane of the nose and throat; dry crystalline mercuric 
sulphate remains. If residual particles of mercury are ob- 
served, the mass should be dampened with sulphuric acid and 
again heated. 
Bu-1 iroducts.—In chemical manufactories, secondary products, 
such as the sulphurous gas of the above reaction, are termed by- 
products, and, if of value, are utilized. In the present case the 
gas is of no immediate use, and is therefore allowed to escape. 
When very pure sulphurous acid gas is required for experiments 
on the small scale, this would be the best method of making it, a 
delivery-tube being adapted by a cork to the mouth of a flask con- 
taining the acid and metal. The sulphate of mercury would then 
become the by-product. MERCURY 
Mercuric Oxysulphate.—Water decomposes mercuric sulphate into 
a soluble acid salt and an insoluble yellow oxysulphate (llg302S04). 
The latter is called Turpeth mineral, from its resemblance in color to 
the powdered root of Ipomcea turpethum, an Indian substitute for 
jalap. The yellow sulphate or subsulphate of mercury (Hydrargyri 
Subsulphas Flams, U. S. I\) is official. It should be entirely soluble 
in 20 parts of hydrochloric acid. 
Fifth Synthetical Reaction.—Rub a portion of the dry mer- 
curic sulphate of the previous reaction with as much mercury 
as it already contains; the product, when the two have thor- 
oughly blended, is mercurous sulphate (Hg.2S04) : it may be 
retained for a subsequent experiment. 
Molecular Weight.—The exact proportion of mercury to sulphate 
is merely a matter of calculation; for the combining proportion of a 
compound (if it possess any combining power) is the sum of the com- 
bining proportions of its constituents. In other words, the combining 
weight of a molecule is simply the sum of the weights of its constituent 
atoms, or, more generally, the molecular weight of a compound is the 
sum of the atomic weights of its elements. In accordance with this 
rule (sometimes called the fourth law of chemical combination, 
though only a deduction from the first—p. 47), 296 of mercuric 
sulphate and 200 of mercury (about 3 to 2) are the exact propor- 
tions necessary to the formation of mercurous sulphate. 
The Two Chlorides. 
Sixth Synthetical Reaction.—Mix thoroughly a few grains 
of dry mercuric sulphate with about four-filths its weight ol 
chloride of sodium, and heat the 
mixture slowly in a test-tube in a 
fume-chamber or in the open air to 
leeward of the operator; mercuric 
chloride (HgCb), or corrosive subli- 
mate (Hydrargyri Perchloridum, 
B. P., Hydrargyri Chloridum Cor- 
rosivum, U. S. R), sublimes and con- 
denses in the upper part of the tube 
in heavy colorless crystals or a crys- 
talline mass. Somewhat larger quan- 
tities (in the proportion of 20 of sul- e 
phate to 16 of salt, and, vide infra, ° 
1 of black oxide of manganese) may 
be sublimed in a pair of two-ounce 
or three-ounce round-bottomed gallipots, the one inverted over 
the other, and the joint luted by moist fireclay (the powdered 
clay kneaded with water to the consistence of dough). The 
luting having been allowed to dry (somewhat slowly, to avoid 
Fig. 36. 
Sublimation. 198 
THE METALLIC RADICALS. 
cracks), the pots are placed upright on a sand-tray (plate-shape 
answers very well), sand piled round the lower and a portion 
of the upper pot, and the whole heated over a good-sized gas- 
flame (if an air-gas flame, it should be an inch and a half wide 
and four or five inches long) for an hour or more (see fig. 36— 
pots raised to show joint), lied Iodide of Mercury and Calomel 
may be sublimed in the same way. The former requires less, 
the latter more, heat than corrosive sublimate. 
Mercuric 
sulphate. 
IlgSO* + 2NaCl - HgCl2 + Na,SOt 
Chloride of 
sodium. 
Mercuric 
chloride. 
Sulphate of 
sodium. 
Note.—If the mercuric sulphate contain any mercurous sulphate, 
some calomel may be formed. This result will be avoided if 2 or 3 
per cent, of black oxide of manganese be previously mixed with the 
ingredients, the action of which is to eliminate chlorine from the 
excess of chloride of sodium used in the process, the chlorine con- 
verting any calomel into corrosive sublimate. Manganate of sodium 
and a lower oxide of manganese are simultaneously produced. 
Precaution.—The operation is directed to be conducted with care 
in a fume-chamber or in the open air, because the vapor of corrosive 
sublimate, which might possibly escape, is very acrid and highly poi- 
sonous. Its vulgar name is indicative of its properties. 
Ten grains of perchloride of mercury and the same quantity of 
chloride of ammonium in one pint of water form the Liquor Hydrar- 
gyri Perchloridi, 15. P. A dilute aqueous solution of perchloride of 
mercury is liable to decomposition, calomel being precipitated, water 
decomposed, hydrochloric acid formed, and oxygen gas evolved. The 
presence of excess of chloride of ammonium, with a portion of which 
the mercuric chloride forms a stable double salt, prevents the decom- 
position. 
Seventh Synthetical Reaction.—Mix a few grains of the 
mercurous sulphate of the fifth reaction with about a third of 
its weight of chloride of sodium, and sublime in a test-tube; 
crystalline mercurous chloride (HgCl) or calomel (Hydrargyri 
Suhchloridum, B. P., Hydrargyri Chloridum Mite, U. S. P.) 
results. Larger quantities may be prepared in the manner 
directed for corrosive sublimate, a somewhat higher tempera- 
ture being employed ; similar precaution must also be observed. 
The proportions are 10 of mercuric sulphate to 7 of mercury 
and 5 of dry chloride of sodium. “ Moisten the sulphate of 
mercury with some of the water, and rub it and the mercury 
together until globules are no longer visible; add the chloride 
of sodium, and thoroughly mix the whole by continued tritu- 
ration. When dry, sublime by a suitable apparatus into a 
chamber of such a size that the calomel, instead of adhering 
to its sides as a crystalline crust, shall fall as a fine (dull-white) MERCURY. 
199 
powder on its floor. Wash this powder with boiling distilled 
water until the washings cease to be darkened by a drop of 
sulphydrate of ammonium. Finally, dry at a heat not ex- 
ceeding 212° F., and preserve in a jar or bottle impervious to 
light.” 
Hg2S04 + 2NaCI - 2HgCl + Na2S04 
The term calomel kalos, good, and /ud.ac, melas, black) is 
said to relate to the use of the salt as a good remedy for black bile, 
but probably was simply indicative of the esteem in which black 
sulphide of mercury was held, the compound to which the name 
calomel was first applied. 
Test for corrosive sublimate in calomel.—If the mercurous sul- 
phate contains mercuric sulphate, some mercuric chloride will also 
be formed. Corrosive sublimate is soluble in water, calomel insol- 
uble ; the presence of the former may therefore be proved by boiling 
a few grains of the calomel in distilled water, filtering and testing 
by sulphuretted hydrogen or sulphydrate of ammonium as described 
hereafter. If corrosive sublimate is present, the whole bulk of the 
calomel must be washed with hot distilled water till the filtrate 
ceases to give any indications of mercury. Corrosive sublimate is 
more soluble in alcohol, and still more in ether; calomel insoluble. 
Ether in which calomel has been digested should, therefore, after 
filtration, yield no residue on evaporation. Calomel is converted 
by hydrocyanic acid into mercuric salt, and a black powder readily 
yielding metallic mercury. Powell and Bayne have shown that a 
certain proportion of hydrochloric acid arrests this action. 
Note.—The above process is that of the Pharmacopoeia; but cal- 
omel may also be made by other methods. Calomel mixed with lard 
forms the Cnguentum Hydrargyri Subchloridi, B. I’., with sulphu- 
rated antimony, guaiaeum resin, and mucilage of tragacanth the 
Pilulce Antimonii Composite, U. S. P., or “ Plummer's Pills,” and 
with colocynth, jalap, and gamboge the Pilulce Catharticce Contpo- 
sitie, U. S. P. 
Mercurous 
sulphate. 
Chloride of 
sodium. 
Mercurous 
chloride. 
Sulphate of 
sodium. 
The Two Oxides, 
Eighth Synthetical Reaction.—Evaporate the mercuric nitrate 
of the third reaction to dryness in a small dish in a fume- 
chamber, or in the open air if more than a few grains have 
been prepared, and heat the residue till no more fumes are 
evolved; red mercuric oxide (IlgO), “ lied Precipitate,” the 
lied Oxide of Mercury (Ilydrargyri Oxidum Rubrum, U. S. P.), 
remains. 
2(Hg2NOs) - 2HgO + 4N02 + 02 
Mercuric 
nitrate. 
Mercuric 
oxide. 
Nitric 
peroxide. 
Oxygen. 
The nitric constituents of the salt may he partially economized by 
previously thoroughly mixing with the dry mercuric nitrate as much 200 
THE METALLIC RADICALS. 
mercury as is used in its preparation, or as much as it already con- 
tains (ascertained by calculation from the atomic weights and the 
weight of nitrate under operation, as in making mercurous sulphate 
p. 197), and well heating the mixture. In this case the free mercury 
is also converted into mercuric oxide. This is the official process, 
the Pharmacopoeial quantities being four ounces of mercury dissolved 
in four and a half fluidounces of nitric acid diluted with two ounces 
of water, the solution evaporated to dryness, the residue thoroughly 
mixed with four ounces of mercury, and the whole heated until acid 
vapors cease to be evolved. (Mercuric oxide is tested for nitrate by 
heating a little of the sample in a test-tube, when orange nitrous 
vapors are produced and are visible in the upper part of the tube, 
if nitrate is present.) 
Mercuric 
nitrate. 
Hg2N03 + Ilg = 2IIgO + 2X0, 
Mercury. 
Mercuric 
oxide. 
Nitric 
peroxide. 
Mercuric oxide is an orange-red powder, more or less crystalline 
according to the extent to which it may have been stirred during 
preparation from the nitrate, much rubbing giving the crystals a 
pulverulent character. Mercuric oxide, in contact with oxidiz- 
able organic matter, is liable to reduction to black or mercurous 
oxide. 
Ninth Synthetical Reaction.—To solution of potash or soda, 
or lime-water, in a test-tube or larger vessel, add solution of 
corrosive sublimate or of mercuric nitrate; yellow oxide of 
mercury (Hydrargyri Oxidum Flavitm, U. S. P.), or yellow 
mercuric oxide (IlgO), is precipitated. 
HgCl2 + 2KHO = HgO + 2KC1 + H20 
Mercuric 
chloride. 
Hydrate of 
potassium. 
Mercuric 
oxide. 
Chloride of 
potassium. 
Water, 
The precipitate only differs physically from the red mercuric oxide; 
the yellow is in a more minute state of division than the red. Mer- 
curic oxide is very slightly soluble in water, but sufficiently so to 
communicate a decidedly metallic taste. 
Tenth Synthetical Reaction.—To calomel add solution of pot- 
ash or soda, or lime-water; black oxide of mercury, or mer- 
curous oxide (Hg20) is produced, and may be filtered off, 
washed, and dried. (This reaction and the formation of a 
white curdy precipitate, on the addition of solution of nitrate 
of silver to the filtrate from the mercurous oxide, acidified by 
nitric acid, form sufficient evidence of a powder being or con- 
taining calomel. The curdy precipitate is chloride of silver.) 
Thirty grains of calomel to ten ounces of lime-water form the Lotio 
Hydrargyri Nigra, B. P. 
2HgCl + Ca2II0 = Ilg20 + CaCl, + H,0 
Mercurous 
chloride. 
Hydrate of 
calcium. 
Mercurous 
oxide. 
Chloride of 
calcium. 
Water. MERCURY 
201 
(h) Analytical Reactions ( Tests) 
(The mercury occurring as mercuric or mercurous salts.) 
First Analytical Reaction.— The Copper Test. Deposition 
of mercury upon, and sublimation from copper.— Place a small 
piece of bright copper, about half an inch long and a quarter 
of an inch broad, in a solution of any salt of mercury, mer- 
curous or mercuric, and heat in a test-tube; the copper be- 
comes coated with mercury in a fine state of division. (The 
absence of any notable quantity of nitric acid must be insured 
or the copper itself will be dissolved. See notes below.) Pour 
away the supernatant liquid from the copper, wash the latter 
once or twice by pouring water into, and then out of, the tube, 
remove the metal, take off' excess of water by gentle pressure 
in a piece of filter-paper, dry the copper by passing it quickly 
through a flame, holding it by the fingers; finally, place the 
copper in a dry narrow test-tube, and heat to redness in a flame, 
the tube being held almost horizontally ; the mercury sublimes 
and condenses as a whitish sublimate of minute globules on the 
cool part of the tube outside the flame. The globules aggre- 
gate on gently pressing with a glass rod, and are especially 
visible where flattened between the rod and the side of the test- 
tube. 
Notes on the Test.—This is a valuable test, for several reasons: 
It is very delicate when performed with care. It brings before the 
observer the element itself—one which from its metallic lustre and 
fluidity cannot be mistaken for any other. It separates the element 
both from mercurous and mercuric salts. Mercury can in this way 
readily be eliminated in the presence of most other substances, or- 
ganic or inorganic. 
In performing the test the presence of any quantity of nitric acid 
may be avoided by adding an alkali until a slight permanent 
precipitate appears, and then reacidifying with a few drops of 
acetic or hydrochloric acid; or by concentrating in an evap- 
orating-dish after adding a little sulphuric acid, and then re- 
diluting. 
Second Analytical Reaction.—To a few drops of a solution 
of a mercuric salt (corrosive sublimate, for example) add solu- 
tion of iodide of potassium, drop by drop ; a precipitate of mer- 
curic iodide (Hgl2) forms, and at first quickly redissolves, but 
is permanent when sufficient iodide of potassium has been 
added. Continue the addition of iodide of potassium ; the pre- 
cipitate is once more redissolved. 
Teds continued. (The mercury occurring as mercuric salt.) 202 
THE METALLIC RADICALS. 
Third Analytical Reaction.—Add a solution of mercuric salt 
to solution of ammonia, taking care that the mixture, after well 
stirring, still smells of ammonia; a white precipitate falls. 
Ammoniated Mercury, 
Performed in a test-tube, this reaction is a very delicate test of 
the presence of a mercuric salt; performed in larger vessels, the 
mercuric salt being corrosive sublimate (3 ounces dissolved in 3 pints 
of distilled water, the solution poured into 4 fluidounces of Solution 
of Ammonia, and the precipitate washed and dried over a water- 
bath), it is the usual process for the preparation of “ white precipi- 
tate,” the old “ ammonio-chloride,” or “amido-chloride of mercury” 
(so called because then considered to be a compound of mercury 
with chlorine and with amidogen, NH2, or IIgCl2, IIg2NII2, chloride 
and amide of mercury), now known as Ammoniated Mercury (Hy- 
drargyrum Ammoniatum, U. S. P.). 
Constitution of Ammoniated Mercury.—This precipitate is con- 
sidered to be the chloride of mercuric ammonium (NH2IIg//Cl)— 
that is, chloride of ammonium (NII4C1), in which two univalent atoms 
of hydrogen are replaced by one bivalent atom of mercury. 
Mercuric 
chloride. 
IIgCl2 + 2N1IJIO = NH2IIg//Cl + NH4C1 + 2II20 
Ammonia. 
“White 
precipitate.” 
Chloride of 
ammonium. 
Water. 
Varieties of Ammoniated Mercury.—If the order of mixing be 
reversed, and ammonia be added to solution of mercuric chloride, 
a double chloride of mercuric-ammonium and mercury results 
(NHJI gCl,HgCl2): it contains 76.55 per cent, of mercury. Pre- 
viously to the year 1826, '‘white precipitate” was officially made by 
adding a fixed alkali to a solution of equal parts of corrosive subli- 
mate and sal-ammoniac ; this gave a double chloride of mercuric am- 
monium and ammonium (NH2HgCl,NH4Cl), containing 65.57 per 
cent, of mercury. This compound is now known as Ufusible white 
precipitate,” because at a temperature somewhat below redness it 
fuses and then volatilizes. The “white precipitate” which has been 
official since 1826 contains 79.52 per cent, of mercury. The true 
compound may be distinguished as “ infusible white precipitate,” 
from the fact that when heated it volatilizes without fusing. An 
ointment of this body is official (Unguentum Hydrargyri Ammo- 
niati, U. S. P.). Prolonged washing with water converts “ white 
precipitate” into a yellowish compound (NH2HgCl,lIgO); hence 
the official preparation is seldom thoroughly freed from the chloride 
of ammonium which is formed during its manufacture, and which, 
if present in larger proportion than seven or eight per cent., gives 
to it the character of partial or complete fusibility. With iodine, 
chlorine, or bromine, white precipitate may yield the highly explo- 
sive iodide, chloride, or bromide of nitrogen. 
Note.—Chloride of mercuric-ammonium is only one member of a 
large class of compounds derivable from the various salts of ammo- 
nium by displacement of atoms of hydrogen in the molecules by MERCURY. 
203 
other atoms. The composition of the chloride of mercurous-ammo- 
nium (see next page) and of ammonio-nitrate of silver is consistent 
with this view. 
fin 
NI il 01 
r Kg' ] 
■ r* 
pig") 
In r 
* \fh 
Chloride of 
common 
ammonium. 
Chloride of 
mercurous- 
ammonium. 
Chloride of 
mercuric- 
ammonium. 
Nitrate of 
argent-ammon- 
animonium. 
The composition of the ammonio-: 
189) is consistent with the second 
mulae, the first being that of sulp 
sulphates of copper (pp. 173 and 
and third of the following for- 
liate of ammonium :— 
r ii, ] 
N - II, ' SO 
| n2 I 
l H, J 
r Cu" i 
\ I Am2 I gQ 
I |J2 j 
f Cu" 1 
N> 11™; |so* 
The iodide of dimercuric ammonium (Nilgai) is formed in test- 
ing for ammonia by the “Nessler” reagent {rule Index). Troost 
has obtained NHAm3Cl. 
Fourth Analytical Reaction.—Pass sulphuretted hydrogen 
through a mercuric solution ; a black precipitate of mercuric 
sulphide (HgS) falls. 
Note.—Sulphuretted hydrogen also precipitates mercurous sul- 
phide (Ilg2S) from mercurous solutions; and in appearance the pre- 
cipitates are alike; hence this reagent does not distinguish between 
mercurous and mercuric salts. But in the course of systematic 
analysis, mercuric salts are thrown down from solution as sulphide 
after mercurous salts have been otherwise removed. The sulphides 
are insoluble in sulphydrate of ammonium. 
Note.—An insufficient amount of the gas gives a white or colored 
precipitate of oxysulphide. Prolonged contact with sulphuretted 
hydrogen-water or a sulphydrate, especially when the mixture is 
kept warm, converts the black into a red sulphide. 
JFAhiops Mineral, the Hydrargyri Sulphuretum mm Sulphure, is 
a mixture of sulphide of mercury and sulphur, obtained on tritu- 
rating the elements in a mortar till globules are no longer visible. 
Its name is probably in allusion to its similarity in color to the skin 
of the It was formerly official. 
Vermilion or artificial cinnabar, is mercuric sulphide prepared by 
sublimation (Hydrargyri Sulphidum Rubrum, U. S. P.). For a 
description of the Chinese method of manufacturing it see the 
Pharmaceutical Journal for December 17, 1881. 
Texts continued. (The mercury occurring as mercurous salt.) 
Fifth Analytical Reaction.—To a solution of a mercurous 
salt (the mercurous nitrate obtained in the second synthetical 204 
TIIE METALLIC RADICALS. 
reaction, for example) add hydrochloric acid or any soluble 
chloride; a white precipitate of calomel (HgCl) occurs. 
This reaction was formerly official in the Dublin Pharma- 
copoeia as a process for the preparation of calomel. 
Sixth Analytical Reaction.—To solution of a mercurous 
salt add iodide of potassium; green mercurous iodide (Hgl) 
is precipitated. 
Seventh Analytical Reaction.—To a mercurous salt, dissolved 
or undissolved (e. g. calomel), add ammonia; black salt (e. g. 
chloride) of mercurous ammonium NH2Hg2Cl) is formed (see 
previous page). 
The elimination of mercury in the actual state of metal by 
the copper test, coupled with the production or non-production 
of a white precipitate on the addition of hydrochloric acid to 
the original solution, is usually sufficient evidence of the pres- 
ence of mercury and its existence as a mercurous or mercuric 
salt. But other tests may sometimes be applied with advan- 
tage. Thus, metallic mercury is deposited on placing a drop 
of the solution on a plate of gold (sovereign or half sovereign), 
and touching the drop and the edge of the plate simultaneously 
with a key; an electric current passes, under these circum- 
stances, from the gold to the key, and thence through the 
liquid to the gold, decomposing the salt, the mercury of which 
forms a white metallic spot on the gold, while the other ele- 
ments go to the iron. This is called the galvanic test, and is 
useful for clinical purposes. Solution of stannous chloride 
(SnCl2)—see Index—from the readiness with which it forms 
stannic salts (SnCl4, Sn02, etc.), gives a white precipitate of 
mercurous chloride in mercuric solutions, and quickly still 
further reduces this mercurous chloride (and other mercury- 
salts) to a grayish mass of finely divided mercury; this is the 
old magpie test, probably so called from the white and gray 
appearance of the precipitate. The reaction may even be ob- 
tained from such insoluble mercury compounds as “ white pre- 
cipitate.” Confirmatory tests for mercuric and mercurous 
salts will be found in the action of solution of potash, solution 
of soda, lime-water, solution of ammonia, and solution of iodide 
of potassium. ( Vide pages 201 to 204.) Normal alkaline 
carbonates produce yellowish mercurous carbonate and brown- 
ish-red mercuric carbonate, both of them unstable. Al- 
kaline bicarbonates give mercurous carbonate with mercurous 
salts, and with mercuric salts white (becoming red) mercuric 
oxysalt. Yellow chromate of potassium (K2Cr04) gives with 
Other Tests far Mercury. QUESTIONS AND EXERCISES. 
205 
mercurous salts, a red precipitate of mercurous chromate 
Mercury and all its compounds are volatile, 
many of them being decomposed, at the same time yielding 
globules of condensed metal: the experiment is most con- 
veniently performed in a test-tube. All dry compounds of 
mercury are decomposed when heated in a dry test-tube with 
dried carbonate of sodium, mercury subliming and condensing 
in visible globules or as a whitish deposit yielding globules 
when rubbed with a glass rod. 
Antidote.—Albumen gives a white precipitate with solution 
of mercuric salts ; hence the importance of administering white 
of egg while waiting for a stomach-pump in cases of poisoning 
by corrosive sublimate. 
QUESTIONS AND EXERCISES. 
293. Name the chief ore of mercury, and describe a process for 
the extraction of the metal. 
294. Give the properties of mercury. 
295. In what state does mercury exist in “ Gray Powder'’ ? 
296. What other preparations of metallic mercury itself are em- 
ployed in medicine? 
297. State the relation of the mercurous to the mercuric com- 
pounds. 
298. Distinguish between an alloy and an amalgam. 
299. State the formulae of the two Iodides of Mercury. 
300. Under what circumstances does mercuric iodide assume two 
different colors? 
301. Illustrate the chemical law of Multiple Proportions as ex- 
plained by the atomic theory, employing for that purpose the stated 
composition of the two iodides of mercury. 
302. Write down the formulae of Mercurous and Mercuric Ni- 
trates and Sulphates. 
303. IIow is Mercuric Sulphate prepared? 
304. What is the formula of “ Turpeth Mineral” ? 
305. Describe the processes necessary for the conversion of mer- 
cury into Calomel and Corrosive Sublimate, using diagrams. 
306. Why is black oxide of manganese sometimes mixed with the 
other ingredients in the preparation of Corrosive Sublimate? 
307. Give the chemical and physical points of difference between 
Calomel and Corrosive Sublimate. 
308. IIow may a small quantity of Calomel in Corrosive Subli- 
mate be detected ? 
309. Work out a sum showing how much mercury will be required 
in the manufacture of one ton of Calomel. Ans. 17 cwt. nearly. 
310. Mention official preparations of the chlorides of mercury. 
311. Give the formulae and mode of formation of the Red, Yellow, 
and Black Oxides of Mercury, employing diagrams. 206 
TIIE METALLIC RADICALS. 
312. Explain the action of the chief general test for mercury. 
313. How are mercurous and mercuric salts analytically distin- 
guished ? 
314. Give a probable view of the constitution of Hydrargyrum 
Ammoniatum, and an equation showing how it is made. 
315. What is the best temporary antidote in cases of poisoning 
by mercury? 
Symbol Pb. Atomic weight 200.5. 
LEAD. 
Source.—The ores of lead are numerous ; but the one form which 
the metal is chiefly obtained is the sulphide of lead (PbS), or galena 
(from yaAT/vr), galene, tranquillity, perhaps from its supposed effect 
in allaying pain). 
Preparation.—The ore is first roasted in a current of air; much 
sulphur is thus burnt off as sulphurous acid gas, while some of the 
metal is converted into oxide and a portion of the sulphide oxidized 
to sulphate. Oxidization being stopped when the mass presents 
certain appearances, the temperature is raised, and the oxide and 
sulphate, reacting on undecomposed sulphide, yield the metal and 
much sulphurous acid gas:— 
2PbO + PbS = Pbj + SO, 
PbS04 + PbS = Pb2 + 2S02. 
Uses.—The uses of lead are well known. Alloyed with arsen- 
icum it forms common shot, with antimony gives type-metal, with 
tin solder, and in smaller quantities enters into the composition of 
Britannia metal, pewter, and other alloys. Lead is so slightly 
attacked by acids that chemical vessels and instruments are often 
made of it. Even hot hydrochloric acid only slowly converts it into 
chloride of lead, with evolution of hydrogen. Sulphuric acid by 
aid of air only very slowly attacks it, with formation of sulphate of 
lead and water. Even nitric acid very slowly converts it into 
nitrate, with evolution of nitric oxide and nitrous oxide gases and 
water. 
The salts of lead used in pharmacy and all other preparations 
of lead are obtained, directly or indirectly, from the metal itself. 
Heated in a current of air, lead combines with oxygen and forms 
oxide of lead (PbO) (Plumbi Oxidurn, U. S. P.), a yellowish powder 
(massicot), or if fused and solidified a brighter reddish-yellow heavy 
mass of bright scales, termed litharge (from ?J0oq, lithos, a stone, and 
apyvpog, arguros, silver). It is from this oxide that the chief lead 
compounds are obtained. Oxide of lead, by further roasting in a 
current of air, yields red lead (or minium), Pb304, or Pb022Pb0. 
Both oxides are much used by painters, paper-stainers, and glass- 
manufacturers. White lead is a mixture of carbonate (PbC03) and 
hydrate of lead (Pb2HO) (commonly 2 molecules of the former to 1 
of the latter), usually ground up with about 7 per cent, of linseed 
oil; it is made by exposing lead, cast in spirals or little gratings, to 207 
the action of air, acetic fumes, and carbonic acid, the latter gen- 
erated from decaying vegetable matter, such as spent tan; oxyace- 
tate of lead slowly but continuously forms, and is as continuously 
decomposed by the carbonic acid, with production of hydrate and 
carbonate, or dry white lead. The grating-like masses, when ground, 
form the heavy white pulverulent official Plnmbi Carbonas, U. S. P. 
The latter is the active constituent of Unguentum Plumbi Carbonatis, 
U. S. P., the old Unguentum Cerussce. 
Lead compounds are poisonous, producing saturnine colic, or even 
paralysis. These effects are termed saturnine from an old name of 
lead, Saturn. The alchemists called lead Saturn, first, because they 
thought it the oldest of the seven then known metals, and it might 
therefore be compared to Saturn, who was supposed to be the father 
of the gods; and, secondly, because its power of dissolving other 
metals recalled a peculiarity of Saturn, who was said to be in the 
habit of devouring his own children. 
Qvantivalence.—The atom of lead is sometimes quadrivalent 
(PI,////), most of the compounds used in medicine it exerts 
bivalent activity only (Pb//). 
LEAD. 
Reactions having (a) Synthetical and (7>) Analytical 
Interest. 
(a) Synthetical Reactions 
Acetate of Lead. 
first Synthetical Reaction.—Place a few grains of oxide of 
lead in a test-tube, add about an equal weight of water and 
two and a half times its weight of acetic acid, and boit; the 
oxide dissolves (or, rather, disappears—dissolves with simul- 
taneous decomposition) and forms a solution of acetate of lead 
(Pb2C2IIA). When cold, or on evaporation if much water 
Has been used (the solution being kept faintly acid), crystals 
of acetate of lead (Pb2C2H302,8H20) are deposited. Larger 
quantities are obtained by the same method. 
PbO + 2HCJIA = Pb2C2H302 + H20 
This is the official Plumbi Acetas, U. S. P. The salt is termed 
Sugar of Lead, from its sweet taste. Besides its direct use in Phar- 
macy, it forms three-fourths of the Pilula Plumbi cum Opio, B. P. 
Oxide of lead. 
Acetic acid. 
Acetate of lead. 
Water. 
Subacetate or Oxyacetate of Lead. 
Second Synthetical Reaction.—Boil acetate of lead with 
about four times its weight of water, and rather more than 
two-thirds its weight of oxide of lead; the resulting filtered 
liquid is solution of oxyacetate of lead, Liquor Plumbi Sub- 
acetutis, U. S. P. 208 
THE METALLIC RADICALS. 
The official Liquor is made by boiling 170 parts of acetate and 
120 of oxide in 800 of distilled water for half an hour (constantly 
stirring), filtering, and making up for any loss during evaporation 
by diluting the filtrate with boiled and cooled distilled water until 
it weighs 1000 parts. Sp. gr. 1.228. 
A similar solution was used by M. Goulard, who called it Extrac- 
tum Saturni, and drew attention to it in 1770. It is now frequently 
termed Goulard's Extract. A more dilute solution, 3 of Liquor and 
97 of boiled and cooled distilled water, is also official in the Phar- 
macopoeia, under the name of Liquor Plumbi Subacetatis Dilutus. 
The latter is commonly known as Goulard Water or “ Lead Water.’’ 
The stronger solution is the chief ingredient in Ceratum Plumbi 
Subacetatis,. U. S. P., a slight modification of the old Goulard's 
Cerate. 
Oxyacetates of Lead.—The official subacetate of lead is not a 
definite chemical salt. It is probably a mixture of two subacetates 
of lead, which are well-known crystalline compounds, and which the 
author is disposed to regard as having a constitution similar to that 
he has already indicated for some other salts (see Iron and Antimony, 
also Bismuth). Exposed to air it absorbs carbonic acid gas, and 
hydrato-carbonate of lead is deposited. 
U. S. P. 
Acetate of Lead (3 molecules) . . Pb3 6C2II302 
Pyro-oxyacetate of lead .... Pb304C.2lI302 
Goulard's oxyacetate of lead . . . Pb3022C2II302 
Oxide of lead (3 molecules) . . . Pb303. 
Oxide of 
lead. 
PbO + Pb2C2H302 = Pb202C2H302 
Acetate of 
lead. 
Official “ subacetate.” 
or 3PbO + 3(Pb2C2II.,02) = Pb304C2II302 + Pb3022C2TI302 
Oxide of 
lead. 
Acetate of 
lead. 
I’y ro-oxy ace tate. 
The official “ subacetate.” 
Goulard’s oxyacetate. 
Nitrate of Lead. Red Lead. Peroxide of Lead. 
Third Synthetical Reaction.—Digest a few grains of red lead 
in nitric acid and water; nitrate of lead (Pb2N03) is formed, 
and remains in solution, while a puce-colored peroxide of lead 
(Pb02) is precipitated. 
Nitrate of Lead (Plumbi Nitras, U. S. P.) is more directly made 
by dissolving litharge (PbO) in nitric acid—■ 
PbO + 2IINO3 = Pb2N03 + II20; 
but the former reaction serves to bring before the reader two other 
oxides of lead, namely, red lead (Pb304) and peroxide of lead (Pb02). 
In the latter oxide the quadrivalent character of lead is obvious. 
Nitrate of lead is used officially in preparing iodide of lead ; for this 
purpose the above mixture is filtered, the precipitate of peroxide of 
lead purified from adhering nitrate by passing hot water through 
the filter, the filtrate and washings evaporated to dryness to remove 
excess of nitric acid, the residual nitrate of lead redissolved by ebul- LEAP 
209 
lition with a small quantity of hot water, and the solution set aside 
to crystallize, or a portion at once used for the following experiment. 
Nitrate of lead forms white crystals derived from octahedra. 
, Peroxide of lead dissolved in strong hydrochloric acid apparently 
yields an unstable perchloride (PbCIJ. 
Iodide of Lead. 
Fourth Synthetical Reaction.—To a neutral solution of ni- 
trate of lead add solution of iodide of potassium ; a precipitate 
of iodide of lead (Pbl2) falls (Plumbi Todidinn, U. S. P.). It 
is soluble in solution of chloride of ammonium. Equal weights 
of the salts may be used in making large quantities. 
Pb2N03 + 2KI = Pbl2 + 2KXO, 
Nitrate of 
lead. 
Iodide of 
potassium. 
Iodide of 
lead. 
* . '-'S 
Nitrate of 
potassium. 
Crystal* of Iodide of Lead.—Heat the iodide of lead with 
the supernatant liquid, and if necessary filter; the salt is dis- 
solved, and again separates in golden crystalline scales as the 
solution cools. 
Fifth Synthetical Reaction.—Boil together in a small dish 
some very finely-powdered oxide of lead, with nearly twice its 
weight of olive oil, and ten or twenty times as much water, 
well stirring the mixture, and from time to time replacing 
water that has evaporated; the product is a white mass of 
oleate of lead (Pb2C18H3302), glycerin remaining in solution 
in the water. Larger quantities are prepared in the same 
manner. 
Oleate of Lead (Lead Plaster), 
3PbO + 3H20 + 2(C3H53C18H3s02) 
Oxide of 
lead. 
Water. 
Oleate of glyceryl 
(olive-oil or oleine). 
3(Pb2ClsH3302) + 2(C3H53HO) 
Oleate of lead 
(lead plaster). 
Hydrate of glyceryl 
(glycerin). 
The action between the oxide of lead and olive oil is slow, requir- 
ing several hours for its completion. 
1 he glycerin may he obtained by treating the aqueous product of 
the above reaction with sulphuretted hydrogen to remove a trace of 
lead, then digesting with animal charcoal, filtering and evaporating. 
But on the large scale glycerin is produced as a by-product in the 
manufacture of candles, for its elements are found in nearly all 
vegetable and animal fats. ( Vide Index.) If in making lead plaster 
the mixture be evaporated to dryness (Emplastrum Plumbi, U. S. P.), 
some of the glycerin will escape with the steam and some remain 
with the plaster. 210 
THE METALLIC RADICALS. 
Modes of forming chloride, sulphide, chromate, sulphate, hydrate, 
and other salts of lead are incidentally described in the following 
analytical paragraphs. 
(hi) Reactions having Analytical Interest (Tests'). 
First Analytical Reaction.—To a solution of lead salt (ace- 
tate, for example) add hydrochloric acid; a white precipitate 
of chloride of lead (PbCF) is obtained. Boil the precipitate 
with much water; it dissolves, but, on the solution cooling, is 
redeposited in small acicular crystals. Filter the cold solution, 
and pass sulphuretted hydrogen through it; a black precipitate 
(sulphide of lead, PbS) shows that the chloride of lead is sol- 
uble to a slight extent in cold water. 
Note.—A white precipitate on the addition of hydrochloric acid, 
soluble in hot water, and blackened by sulphuretted hydrogen, suf- 
ficiently distinguishes lead salts from those of other metals, but the 
non-production of such a precipitate does not prove the absence of 
a small quantity of lead, chloride of lead being slightly soluble in 
cold water. Hydrochloric acid will be found to be a useful but not 
a delicate test for lead. 
Second Analytical Reaction.—Through a dilute solution of 
a lead salt acidulated with hydrochloric acid pass sulphuretted 
hydrogen ; a black precipitate of sulphide of lead (PbS) occurs. 
Lead in Water.—The foregoing is a very delicate test. Should a 
trace of lead be present in water used for drinking purposes, sulphur- 
etted hydrogen will detect it. On passing the gas through a pint 
of such acidulated water, a brownish color is produced. If the tint 
is scarcely perceptible, set the liquid aside for a day; the gas will 
become decomposed and a thin layer of sulphur be_ found at the 
bottom of the vessel, white if no lead be present, but more or less 
brown if it contain sulphide of lead. 
Third Analytical Reaction.—To solution of a lead salt add 
sulphydrate of ammonium; a black precipitate of sulphide of 
lead falls, insoluble in excess. 
Fourth Analytical Reaction.—To solution of a lead salt add 
solution of chromate of potassium (K2Cr04) ; a yellow precipi- 
tate of chromate of lead (PbCr04) is formed, insoluble in weak 
acids or in solution of chloride of ammonium. 
Chromes.—This reaction has technical as well as analytical in- 
terest. The precipitate is the common pigment termed chrome yel- 
low or lemon chrome. Boiled with lime and water, a portion of the 
chromic radical is removed as soluble chromate of calcium, and an 
oxychromate of lead, of a bright red or orange color (orange chrome), 
is produced. 
Fifth Analytical Reaction.—To solution of a lead salt add 211 
LEAD. 
dilute sulphuric acid, or a solution of a sulphate ; a white pre- 
cipitate of sulphate of lead (PbS04) falls. 
Sulphate of lead is slightly soluble in strong acids, and in solu- 
tions of alkaline salts; it is insoluble in acetic acid. It is readily 
dissolved and indeed decomposed by solution of acetate of ammonium, 
the liquid yielding the ordinary reactions with soluble chromates and 
iodides. 
In dilute solutions the above sulphuric reaction does not take place 
immediately ; the precipitate, however, falls after a time ; its appear- 
ance may be hastened by evaporating the mixture nearly to dryness 
and then rediluting. 
The white precipitate always noticed in the vessels in which diluted 
sulphuric acid is kept is sulphate of lead, derived from the leaden 
chambers in which the acid is made; solubility in strong acid and 
insolubility in weak explains its appearance. 
Antidotes.—From the insolubility of sulphate of lead in water, the 
best antidote, in a case of poisoning by the acetate or other soluble 
salt of lead, is a soluble sulphate, such as Epsom salt, sulphate of 
sodium or alum, vomiting being also induced, or the stomach-pump 
applied as quickly as possible. 
Other tests for lead will be found in the reaction with iodide 
of potassium (vide p. 209) ; with alkaline carbonates, a white 
precipitate (2PbCO;! + Pb2HO) insoluble in excess; with 
alkalies, a white precipitate (Pb2HO) more or less soluble in 
excess; with alkaline phosphates, arseniates, ferrocyanides, and 
cyanides, precipitates mostly insoluble, but of no special analy- 
tical interest. Insoluble salts of lead are decomposed by solu- 
tions of potash (KtIO) or soda (NaHO). 
The metal is precipitated in a beautifully crystalline state by 
metallic zinc and some other metals; the lead tree is thus 
formed. The blowpipe-flame decomposes solid lead com- 
pounds placed in a small cavity in a piece of charcoal, a soft 
malleable bead of metal being produced, and a yellowish ring 
of oxide deposited on the charcoal. 
QUESTION'S AND EXERCISES. 
316. Write down equations descriptive of the smelting of galena. 
317. Mention some of the alloys of lead. 
318. How is litharge produced? 
319. Give the formulae of white lead and red lead. 
320. Describe the manufacture of white lead. 
321. What is the quantivalence of lead? 
322. Draw a diagram expressive of the formation of ordinary Ace- 
tate of Lead. 
323. Describe the preparation and composition of Liquor Plumbi 
Subacetatis. 212 
THE METALLIC RADICALS. 
324. What is the action of nitric acid on red lead, litharge, and 
metallic lead? 
325. How is the official Iodide of Lead prepared ? 
326. Describe the reaction between oxide of lead, water, and olive 
oil, at the temperature of boiling water, and give chemical formulae 
explanatory of the constitution of the products. 
327. Mention the chief tests for lead. 
328. How would you search for lead in potable water ? 
329. What is the composition of chrome yellow? 
330. State a method whereby lead, barium, and silver may be 
separated from each other. 
331. Name the best antidote in case of poisoning by the soluble 
salts of lead. 
Symbol Ag. Atomic weight 107.7. 
SILVER. 
Source.—This element occurs in nature in the free state and as 
ore, the common variety of the latter being sulphide of silver (Ag2S) 
in combination with much sulphide of lead, forming argentiferous 
galena. 
Preparation.—The lead from such galena (p. 206) is melted and 
slowly cooled 5 crystals of lead separate and are raked out from the 
still fluid mass, and thus an alloy very rich in silver is finally ob- 
tained : this is roasted in a current of air, whereby the lead is oxi- 
dized and removed as litharge, pure silver remaining. Other ores 
undergo various preparatory treatments according to their nature, 
and are then shaken with mercury, which amalgamates with and 
dissolves the particles of silver, the mercury being subsequently re- 
moved from the amalgam by distillation. Soils and minerals con- 
taining metallic silver are also treated in this way. An important 
improvement in the amalgamation process, by which the mercury 
more readily unites with the silver, consists in the addition of a 
small proportion of sodium to the mercury—a discovery simul- 
taneously made in England by Crookes, and in New York by Wurtz. 
Silver is not readily affected by the weak acids or other fluids of 
food, though it is rapidly tarnished by sulphur or sulphur com- 
pounds. It does not perceptibly attack hydrochloric acid ; reduces 
strong nitric acid to nitrous anhydride (N.203), and a weaker acid to 
nitric oxide (NO) ; it reduces hot sulphuric acid to sulphurous anhy- 
dride (S02), sulphate of silver (Ag2S04) being formed. The latter 
salt is crystalline and slightly soluble in water. 
Reactions having (a) Synthetical and (/>) Analytical 
Interest. 
(a) Synthetical Reaction. 
Impure Nitrate of Silver. 
First Synthetical Reaction.—Dissolve a silver coin in nitric 
acid; nitric oxide gas (NO) and nitrous anhydride (N203) are SILVER 
213 
evolved, and a solution of nitrates of silver and copper is ob 
tained. 
Silver Coinage.—Pure silver is too soft for use as coin; it is there- 
fore hardened by alloying with copper. The silver money of Eng- 
land contains 7.5, of Prussia 25, and of France 10 and 16.5 percent, 
of copper; for the fineness of the French standard silver is 0.900 in 
the five-franc piece, while an inferior alloy of 0.835 is used for the 
lower denominations. The single-franc piece, composed of the latter 
alloy, is still made to weigh five grammes, the weight originally 
chosen for the franc as the unit of the monetary scale when the fine- 
ness of the coin was 0.900. It has now become a token, like the 
British shilling, of which the nominal value exceeds the metallic 
value. One pound troy of British standard silver is coined into 66 
shillings, of which the metal is worth from 60s. to 62s. according to 
the market price of silver. The standard fineness of this silver is 
0.925, three alloy in 40. British silver coins are a legal tender in 
payments to the amount of 40s. only. 
Chloride of Silver, 
Second Synthetical Reaction.—To the product of the forego- 
ing reaction add water and hydrochloric acid or a soluble chlo- 
ride ; white chloride of silver (AgCl) is precipitated, copper still 
remaining in solution. Collect the precipitate on a filter, and 
wash with water; it is pure chloride of silver. 
Note.—The nitrates of silver and copper may also be separated by 
evaporating the solution of the metals in nitric acid to dryness, and 
gently heating the residue, when the nitrate of copper is decom- 
posed, but the nitrate of silver is unaffected. The latter may be dis- 
solved from the residual oxide of copper by water. 
Chloride of silver may be obtained in crystals by evaporation 
of its solution in ammonia. 
Pure Silver, 
Third Synthetical Reaction.—Place the chloride of silver of 
the previous reaction in a dish, wet it with dilute sulphuric 
acid, and float a piece of sheet zinc on the mixture; metallic 
silver is precipitated, and after about one day wholly removed 
from solution. Collect the precipitate on a filter and wash with 
water; it is pure metallic silver, and is readily fusible into a 
single button. 
Note.—Any considerable quantity of chloride of silver may also 
be reduced to the metallic state by fusion, in a crucible, with about 
half its weight of carbonate of sodium. 
Fourth Synthetical Reaction.—Dissolve the pure silver of the 
previous reaction in nitric acid (3 of silver require about 2 or 
Pure Nitrate of Silver. 214 
TIIE METALLIC RADICALS. 
2o of strong acid diluted with 5 of water), and remove excess 
of acid by evaporating the solution to dryness, slightly heating 
the residue ; the product is pure nitrate of silver. Dissolve by 
heating with a small quantity of water ; on the solution cooling, 
or on evaporation, colorless tabular crystals of nitrate of silver 
are obtained. 
3Ag2 + 8II N0:) = 2NO + 6AgNO, + 411,0 
Silver. 
Nitric acid. 
Nitric 
oxide. 
Nitrate of 
silver. 
Water. 
Notes.—The solution of pure or refined silver (Argentum Purifi- 
catum, B. P.) in nitric acid, evaporation, and crystallization consti- 
tutes the usual process for the preparation of the nitrate (Argenti 
Nitras, U. S. P.). The salt fused with 4 per cent, of hydrochloric 
acid (yielding about 5 per cent, of interlacing chloride of silver), 
and poured into proper moulds, yields the white cylindrical sticks 
or rods (Argenti Nitras Fusus, U. S. P.) commonly termed caustic 
(from /caw, kaio, I burn), or lunar caustic. (The alchemists called 
silver Diana or Luna, from its supposed mysterious connection with 
the moon.) These “ caustic points” commonly contain nitrate of 
potassium, which imparts toughness, the Argenti Nitras Dilutus, 
U. S. P., being formed of equal weights of the salts. The specimen 
of nitrate of silver obtained in the above reaction, dissolved in 
water, will be found useful as an analytical reagent. Nitrate of 
silver is soluble in rectified spirit; but after a time reaction and 
decomposition occur. 
Silver salts are decomposed when in contact with organic matter, 
especially in the presence of light or heat, the metal itself being lib- 
erated, or a black insoluble compound formed. Hence the value of 
the nitrate in the manufacture of indelible ink for marking linen; 
hence, too, the reason of the practice of rendering silver solutions 
clear by subsidence and decantation, rather than by filtration through 
paper; and hence the cause of those cases of actual combustion 
which have been known to occur in preparing pills containing oxide 
of silver and essential oil or other organic matter. Linen marked 
with such ink should not be cleansed by aid of bleaching-liquor, as 
the marked parts are then apt to be rapidly oxidized into perfectly 
rotten matter, holes resulting. Paul says the reaction is as follows: 
Ag20 + CaCl202 = 2AgCl + CaO + 02. 
Oxide of Silver. 
Fifth Synthetical Reaction.—To a few drops of solution of 
nitrate of silver add solution of potash or soda or lime-water; 
an olive-brown precipitate of oxide of silver (Ag20) occurs. 
The washed and dried oxide, like most silver compounds, is 
decomposed by heat, with production of metal. It is also 
readily reduced when triturated with oxidizable or combusti- 
ble substances. (See the previous paragraph). SILVER. 
215 
The Argenti Oxidum, U. S. P., may be thus made: 
2AgN03 + Ca2HO = Ag20 + Ca2X03 + H20 
Nitrate of 
silver. 
Hydrate of 
calcium. 
Oxide of 
silver. 
Nitrate of 
calcium. 
Water 
Methods of forming several other salts of silver are incidentally 
mentioned in the following analytical paragraphs. 
First Analytical Reaction.—To a solution of a silver salt 
add hydrochloric acid or other soluble chloride; a white curdy 
precipitate of chloride of silver falls. Add nitric acid, and 
boil; the precipitate does not dissolve. Pour off' the acid and 
add solution of ammonia ; the precipitate dissolves. Neutralize 
the ammoniacal solution by an acid; the chloride of silver is 
reprecipitated. 
This is the most characteristic test for silver. The precipitated 
chloride is also soluble in solutions of hyposulphite of sodium or 
cyanide of potassium—facts of considerable importance in photo- 
graphic operations. 
Other analytical reagents than the above are occasionally 
useful. Sulphuretted hydrogen, or sulphydrate of ammo- 
nium, gives a black precipitate, sulphide of silver (Ag2S), in- 
soluble in alkalies. Solutions of potash or soda give a brown 
precipitate, oxide of silver (Ag20), converted into a fulmina- 
ting compound by prolonged contact with ammonia. Phos- 
phate of sodium gives a pale yellow precipitate, phosphate of 
silver (Ag3P04), soluble in nitric acid and in ammonia. 
Arseniate of ammonium gives a chocolate-colored precipitate, 
arseniate of silver (Ag3As04), already noticed in connection 
with arsenic acid. Iodide or bromide of potassium gives a 
yellowish-white precipitate, iodide (Argenti lodidum, U. S. P.) 
or bromide of silver (Agl or AgBr), insoluble in acids and only 
slightly soluble in ammonia. Cyanide of potassium gives 
a white precipitate, cyanide of silver (AgCy), soluble in excess, 
sparingly soluble in ammonia, insoluble in dilute nitric acid, 
soluble in boiling concentrated nitric acid. Argenti Cyanidum, 
U. S. P., may be made by distilling a mixture of ferrocyanide 
of potassium and diluted sulphuric acid, and passing the re- 
sulting hydrocyanic acid into a solution of nitrate of silver: 
HCy + AgN03 = AgCy -f HN03 (the precipitate is well 
washed and dried). Yellow chromate of potassium (K2Cr04) 
gives a red precipitate, chromate of silver (Ag2Cr04). Red 
chromate of potassium also gives a red precipitate, acid chro- 
mate of silver (Ag2Cr04,Cr03). Many organic acids afl’ord 
(/;) Reactions having Analytical Interest ( Tests'). 216 
TIIE METALLIC RADICALS. 
insoluble salts of silver. Several metals displace silver from 
solution, mercury forming in this way a crystalline compound 
known as the silver tree, or Arbor Dianne. In the blowpipe- 
flame, silver salts, placed on charcoal with a little carbonate of 
sodium, yield bright globules of metal accompanied by no in- 
crustation as in the corresponding reaction with lead salts ; the 
experiment may be performed with the nitrate, which first 
melts, and then, like all nitrates, deflagrates, yielding a white 
metallic coating of silver which slowly aggregates to a button. 
Antidotes.—Solution of common salt, sal-ammoniac, or any other 
inert chloride should obviously be administered where large doses of 
nitrate of silver have been swallowed. A quantity of sea-water or 
brine would convert the silver into insoluble chloride, and at the 
same time produce vomiting. 
332. By what process is silver obtained from argentiferous ga- 
lena? 
333. What weight of English silver coin will yield one pound of 
pure nitrate of silver? 
334. How may the metal be recovered from an impure mixture of 
silver salts ? 
335. Give a diagram showing the formation of nitrate of silver 
from the metal. 
336. Describe the reaction of lime-water and nitrate of silver. 
337. Mention the chief test for silver, and the precautions to be 
observed in order that silver salts may be distinguished from those 
of lead and mercury. 
338. Name the antidote for silver. 
QUESTIONS AND EXERCISES. 
DIRECTIONS FOR APPLYING SOME OF THE FOREGOING REAC- 
TIONS TO THE ANALYSIS OF AN AQUEOUS SOLUTION OF 
SALTS OF ONE OF THE METALS, COPPER, MERCURY 
(either as mercurous or mercuric salt), Lead, 
Silver. 
Add hydrochloric acid :—• 
Silver is indicated by a white curdy precipitate, soluble in 
ammonia. 
Mercurous salts also by a white precipitate, turned black 
by ammonia. 
Lead by a white precipitate, insoluble in ammonia. Con- 
firm by boiling another portion of the hydrochloric 
precipitate in water; it dissolves. SILVER. 
217 
If hydrochloric acid gives no precipitate, silver and mercu- 
rous salts are absent. Lead can only be present in very small 
quantity. Mercuric salts may be present. Copper may be 
present. Divide the liquid into three portions, and apply a 
direct test for each metal as follows:— 
Lead is best detected by the sulphuric test; the tube 
being set aside for a time if the precipitate does not 
appear at once. 
Mercury is best detected by the copper test. If present, 
here it occurs as mercuric salt. 
Copper betrays itself by the blue color of the liquid under 
examination. Confirm by the ammonia test. 
If the above reactions are not thoroughly conclusive, con- 
firmatory evidence should be obtained by the application of 
some of the other reagents for copper, mercury, lead, or silver. 
Table of short directions for applying some of the 
FOREGOING REACTIONS TO THE ANALYSIS OF AN AQUEOUS 
SOLUTION OF SALTS OF ANY OR ALL OF THE METALS, 
Copper, Mercury (either mercurous or mercuric 
SALT, OR BOTH), LEAD, SILVER. 
Add hydrochloric acid, filter, and wash the precipitate with a 
small quantity of cold water. 
Pb 
Wash 
Ppt. 
Hg(ous) Ag. 
with boiling water. 
Filtrate. 
Cu Hg(ic) Pb. 
Divide into three portions. 
Test for 
Ppt. 
Hg(ous) Ag. 
Add Am HO. 
Filtrate. 
Pb. 
Add II2S04, 
white ppt.* 
Cu by AmHO ; blue sol. 
Ilg (mercuric) by Cu ; 
globules. 
Pb by II2S04; white ppt.* 
Precipitate 
Hg 
(mercurous) 
—black. 
Filtrate. 
Ag. 
Add HN03 
white ppt. 
* Liquids containing only a small quantity of lead do not readily 
yield sulphate of lead on the addition of sulphuric acid. Before lead 
can be said to be absent, therefore, the liquid should be evaporated 
to dryness with one drop of sulphuric acid, and the residue digested 
in water; any sulphate of lead then remains as a heavy white in- 
soluble powder. THE METALLIC RADICALS 
Ppt. 
Ilg(ous) Pb Ag. 
Add AniHO. 
Ilg(ous), black ppt. 
Pb, ppt. still white. 
Ag, ppt. dissolved. 
Note. I.—If HC1 gave no precipi- 
tate, neither Hg(ous) nor Ag is 
present; and Pb only in minute 
amount, if at all. 
Note II.—Hg obtained here 
must have existed in the solu- 
tion as a mercurous salt. 
Note III.—Sb is also precipi- 
tated by HC1, but is dissolved 
on adding more HC1; the Hg, 
Pb, and Ag precipitates are not 
soluble in excess of HOI. 
If HC1 gave no precipitate, the metal is still in the liquid; pass H2S through it. 
Ppt. 
Cu Hg(ic) Pb As Sb. 
As, yellow ppt. 
Sb, orange ppt. 
Cu | 
Hg(ic) V black ppt. 
Pb ) 
Test original solution for 
Cu by AmHO ; blue sol. 
Hg by Cu ; globules. 
Pb by II2S04; white ppt. 
Note I— If II2S gave no precipi- 
tate, neither Cu, Hg, Pb, As, nor 
Sb is present. 
Note II.—Hg and Pb may give 
colored precipitates (oxysul- 
phides, etc.) with H,S if too little 
of the latter has been passed 
through the solution. 
If II2S gave no precipitate, the metal is still in the liquid; 
add AmCl, AmHO, and AniHS. 
Ppt. 
Fe A1 Zn 
Fe, black ppt. 
Test original solution for 
ferric salt by K4Fcy {dark 
blue ppt.) 5 and for ferrous 
salt by K6Fdcy {dark blue 
ppt.). 
Zn } white PP*- 
Test original solution by 
AmHO. 
Al, white ppt. insoluble 
in excess. 
Zn, white ppt. soluble in 
excess. 
If AmHS,etc. gave no pre- 
cipitate, the liquid may still 
contain either Ba, Ca, Mg, K, 
Na, or Am ; add successively 
K2Cr04 for Ba, Am2C204 for 
Ca, Na2IIP04 for Mg. 
If neither Ba, Ca, nor Mg 
is found, examine the origi- 
nal solution for Am by KIIO, 
Na by the flame-test, and K 
by PtCl4. 
SHORT DIRECTIONS FOR THE ANALYSIS OF AN AQUEOUS SOLUTION OF ORDINARY SALTS OF ONE OF THE 
ELEMENTS HITHERTO CONSIDERED. 
Add hydrochloric acid. ANALYTICAL CHART 
219 
Precipitate 
Hg(ous) Pb Ag. 
Wash, boil with water, Alter. 
Filtrate 
Cu Ilg(ic) Pb As Sb Fe A1 Zu Ba Ca Mg K Na Am. 
Pass H2S through the liquid until it ceases to cause any alteration; Alter. 
Precipitate 
Hg(ous) Ag. 
Add AmHO to the 
precipitate on the 
Alter. 
Filtrate 
Pb. 
Add 
H,S04 
white 
precipi- 
tate. 
(See 
footnote, 
p. 217.) 
Precipitate 
Cu Hg(ic) Pb As Sb. 
Wash, digest in AmliS, Alter. 
Filtrate 
Fe A1 Zn Ba Ca Mg K Na 
Add AmHO, AmHS, and Alter 
Am. 
Precipitate 
Cu Hg(ic) 
Wash, dis- 
solve in a few 
dropsofHNOij 
and HC1; 
evap. nearly 
to dryness; 
redissolve in 
H20, divide 
into three, 
and test for 
Cu by AmHO: 
blue solution. 
Hg by Cu; 
globules. 
Pb by H2S04; 
white precip. 
Filtrate 
As Sb. 
Add HC2H302 
and boil; digest 
the precipitate 
in strong HC1; 
boil, dilute, 
Alter. 
Precipitate 
Fe A1 Zn. 
Wash, dissolve in HC1, boil (with 
a few drops of HNO:) if neces- 
sary) ; add KHO, stir, Alter. 
Filtrate 
Ba Ca Mg K Na Am. 
Add Ain2C03; boil, Alter. 
Precip. | Filtrate 
Hg(ous). 1 Ag. 
Black 
precipi- 
tate. 
Add 
HNO:(: 
white 
precipi- 
tate. 
Precipitate 
Ba Ca. 
Wash, dissolve in 
HC0H3O0, boil; 
and K2Cr04, Alter. 
Filtrate 
Mg K Na Am 
Add Am2HAs04 ; stiri 
Alter. 
Precipitate 
Fe. 
? Ferric or 
ferrous. 
Test origi- 
nal solution 
by yellow 
and red 
prussiate. 
Filtrate 
A1 Zn. 
Neutralize by HC1; 
add A mHO,stir, A Iter. 
Precip. 
As. 
Yel- 
low. 
ConArr 
ing c 
soluiir 
H 
Filtrate 
Sb. 
Add II2S. 
Orange 
precip. 
l by test- 
riginal 
n by the 
tests. 
Pptj Filtrate 
Mg.i K Na Am. 
aj ; Evap., ignite, dis- 
•5 isol. in H20; test for 
> K by PtCl4; yel. 
ppt. Na by name; 
yellow. Am. in 
|orig. sol. by NaHO. 
Precip. 
Ba. 
Yellow. 
Filtrate 
Ca. 
Add 
AnioC204; 
white 
precip. 
Precip. 
Al. 
White 
precip- 
tate. 
Filtrate 
Zn. 
Add 
AmHS; 
white 
precip. 
TABLE OF SHORT DIRECTIONS FOR APPLYING SOME OF THE FOREGOING ANALYTICAL REACTIONS TO THE 
ANALYSIS OF AN AQUEOUS SOLUTION OF ORDINARY SALTS OF ANY OR ALL OF THE 
ELEMENTS HITHERTO CONSIDERED. 
(Read the “Memoranda” on the following page.) 
Add hydrochloric acid, and filter. 220 
THE METALLIC RADICALS. 
OUTLINE OF TIIE PRECEDING TABLES. 
IIC1 
H2S 
AmllS 
Am2C03 
Am2IIAs04 
Hg. 
Cu ] 
Zn 
Ba 
Mg 
K 
(as mercurous 
salt) 
Hg 
A1 
Ca 
Na 
Ph 
(partially) 
(as mer- 
curie salt) 
Pb 
a 
HI 
Fe 
Am 
(entirely) J 
Ag 
As 
Sb 
la 
3« 
The practical student should examine solutions containing the 
common metals until he is able to analyze with facility and accuracy. 
In this way he will best perceive the peculiarities of each element 
and their general relations to each other. As the rarer metals are 
not included here, the tables are not complete analytical schemes; 
only general memoranda respecting them will therefore now be given. 
Memoranda relating to the General Analytical 
Table (page 219). 
The group-tests adopted in the Table are, obviously, hydro- 
chloric acid, sulphuretted hydrogen, sulphydrate of ammonium, 
carbonate of ammonium, and arseniate of ammonium. If a 
group-test produces no precipitate, it is self-evident that there 
can be no member of the group present. At first, therefore, 
add only a small quantity of a group-test, and if it produces no 
effect add no more; for it is not advisable to overload a solu- 
tion with useless reagents; substances expected to come down 
as precipitates are not unfrequently held in the liquid by excess 
of acid, alkali, or strong aqueous solution of some group- 
reagent, thoughtlessly added. Indeed, experienced manipulators 
not unfrequently make preliminary trials with group-reagents 
on a few drops only of the liquid under examination ; if a pre- 
cipitate is produced, it is added to the bulk of the original liquid 
and the addition of the group-reagent continued; if a precipi- 
tate is not produced, the few drops are thrown away, and the 
unnecessary addition of a group-reagent thus avoided alto- 
gether, an advantage fully making up for the extra trouble of 
making a preliminary trial. While shunning excess, how- 
ever, care must be taken to avoid deficiency ; a substance only ANALYTICAL MEMORANDA. 
221 
partially removed from solution through the addition of an in- 
sufficient amount of a reagent will appear where not expected, 
he consequently mistaken for something else, and cause much 
trouble, this will not occur if the appearance, odor, or reaction 
of the liquid on test-paper be duly observed. It is also a good 
plan, when a group-reagent has produced a precipitate and the 
latter has been filtered out, to add a little more of the reagent 
to the clear filtrate; if more precipitate is produced, an insuf- 
ficient amount of the group-test was introduced in the first in- 
stance, but the error is corrected by simply refiltering; if no 
precipitate occurs, the mind is satisfied and the way cleared 
for further operations. 
Group-precipitates, or any precipitates still requiring exami- 
nation, should, as a rule, be well washed before further testing; 
this is to remove the aqueous solution of other substances ad- 
hering to the precipitate (the mother-liquor, as it is termed), so 
that subsequent reaction may take place fairly between the re- 
agent used and the precipitate only. A precipitate is some- 
times in so fine a state of division as to retard filtration by 
clogging the pores of the paper, or even to pass through the 
filter altogether; in these cases the mixture may be warmed 
or boiled (or a fresh quantity of the original solution may be 
warmed before the group-test is added), which usually causes 
aggregation of the particles of a precipitate, and hence facili- 
tates the passage of liquids. 
Division of Work.—It is immaterial whether a solution be 
first divided into group-precipitates or each precipitate be ex- 
amined as soon as produced; if the former method be adopted, 
confusion will be avoided by labelling or marking the funnels 
or papers holding the precipitate, “ the HC1 ppt.,” “ the H2S 
ppt.,” and so on. 
The colors and general appearance of the various sulphides 
and hydrates precipitated should be borne in mind, as the ab- 
sence of other bodies, as well as the presence of those thrown 
down, is often at once thus indicated. 
Application of confirmatory tests must be frequent. 
Results of analysis should be recorded neatly in a memo- 
randum-book. 
The various reactions which occur in an analysis have al- 
ready come before the reader in going through the tests for 
the individual metals or in other analytical operations; it is 
unnecessary, therefore, again to draw out equations or dia- 
grams. But the reactions should be thought over, and if not 
perfectly clear to the mind, be written out again* and again till 
thoroughly understood. 222 
RARER METAEEIC RADICALS. 
QUESTIONS AND EXERCISES. 
339. Give processes for the qualitative analysis of liquids contain- 
ing the following substances :— 
a. Antimony and Mercurous salt. 
b. Lead and Calcium. 
c. Silver and Mercurous salt. 
d. Lead and Mercuric salt. 
e. Copper and arsenieum. 
f Arsenicum and Antimony. 
g. Aluminium and Zinc. 
h. Iron and Copper. 
i. Magnesium, Calcium, and Potassium. 
j. Silver, Antimony, Zinc, Barium, and Ammonium. 
340. Enumerate the so-called group-tests. 
341. Give a general sketch of the method of analyzing a solution 
suspected to contain two or more salts of common metals. 
342. Classify the common metals according to their analytical 
relations. 
METALS OF MINOR PHARMACEUTICAL 
IMPORTANCE. 
Thus far has been considered, somewhat in detail, the chemistry 
of the common metals, salts of which are frequently used in medicine 
or in testing medical substances. These are— 
Potassium, Barium, Zinc, Arsenicum, Mercury, 
Sodium, Calcium, Aluminium, Antimony, Lead, 
Ammonium (?), Magnesium, Iron. Copper, Silver. 
Of the remaining metals, nine have considerable interest for the 
student of medicine or of pharmacy, namely :— 
Lithium, Manganese, Tin, Platinum, Bismuth. 
Cerium, Chromium, Gold, Cadmium, 
Compounds of three more occasionally come under notice— 
Strontium, Cobalt, Nickel. 
These twelve metals of minor pharmaceutical interest may he 
shortly studied, a few only of the reactions of each (just those men- 
tioned in the following pages) being performed. When all have 
been thus treated, their respective positions in the analytical groups 
will be indicated, and a tabular scheme by which an analysis of a 
solution containing any metal may be effected. Thus, step by step, 
we may learn how to analyze almost any substance that may occur, 
and know to what extent the presence of a rarer will interfere with 
the ordinary tests for a common element; additional illustrations of 
the working of chemical laws will be acquired, and the store of 
chemical and pharmaceutical facts increased. The opportunity thus 
afforded for improvement in habits of neatness in manipulation, pre- LITHIUM. 
223 
cision, and classification furnishes another and no mean reason why 
such experiments should be prosecuted, the direct value of which 
may not be considerable to medical and pharmaceutical learners. 
LITHIUM. 
Symbol L. Atomic weight 7. 
Lithium is widely distributed in nature, but usually in minute 
proportions compared with other elements. A trace of it may be 
found in most soils and waters, a Cornish spring containing con- 
siderable quantities as chloride. 
One salt used in medicine is the Citrate (L3C6II307) (Lithii Citras, 
U. S. P.), occurring in white deliquescent crystals or powder, pre- 
pared by dissolving 50 grains of the Carbonate (L2C03) and 95 of 
citric acid (50 to 95 if both are quite pure) in 1 ounce of water, 
evaporating to a low bulk, and setting aside in a dry place to crys- 
tallize, or at once evaporating to dryness and powdering the residue. 
The crystals have the formula L..CeIL0„4II„0; dried at 212° F., 
L3C6II507,II20 (Umney). 
3L2C03 + 2H3C6H5Ot = 2L,C6H507 + 3H20 + 3C02 
Carbonate 
of lithium. 
Citric acid. 
Citrate of 
lithium. 
Water. 
Carbonic 
acid gas. 
The benzoate (Lithii Benzoas, , LC7H502, U. S. P.), bromide 
(.Lithii Bromidum, LBr, U. S. P.), and salicylate (Lithii Sn- 
/ieplas, 2LC7H503,H20, U. S. P.) may be similarly prepared 
from the respective acids. 
The above-named lithium salts are officially tested as follows, the 
Bromide being acted upon directly without ignition 
“ On dissolving the residue, left on ignition [of either salt] in 
diluted hydrochloric acid, and evaporating the filtered solution to 
dryness, 1 part of the residue should be completely soluble in 3 
parts of absolute alcohol, which, when ignited, should burn with a 
crimson flame, and the addition of an equal volume of stronger 
ether to the alcoholic solution should produce no precipitate (salts 
of alkalies). On dissolving another portion of the residue in a 
small quantity of water, the solution should produce no precipitate 
with test-solution of oxalate of ammonium (salts of alkaline earths). 
The aqueous solution should remain unaffected by hydrosulphuric 
acid or sulphide of ammonium (abs. of metals).”—U. S. P. 
The carbonate (Lithii Carbonas, U. S. P.) is a white granular 
powder obtained from the minerals which contain lithium ; namely, 
lepidolite (from Xettlc, lepis, a scale, and Xidog, lithos, a stone; it has 
a scaly appearance), triphane (from rpeig, treis, three, and (j>aivcj, 
pkaino, I shine), or spodumene (from anofiou, spoddo, I reduce to 
ashes, in allusion to its exfoliation in the blowpipe-flame), and 
petalite (from nkraXov, petalon, a leaf; its character is leafy and 
laminated). Each contains silicate of aluminium, with fluoride of 
potassium and lithium in the case of lepidolite, and silicate of 
sodium and lithium in the others. Liquor Lithice Effervescens, 224 
RARER METALLIC RADICALS. 
B. P., is a solution of 10 grains of carbonate of lithium in 1 pint 
of water charged with 7 times its volume of carbonic acid gas and 
kept in ordinary aerated-water bottles. “ Half a pint, evaporated 
to dryness, yields 5 grains of a white solid residue, answering to 
the tests for carbonate of lithium. . . . Ten grains of the latter 
salt neutralized with sulphuric acid, and afterwards heated to red- 
'ness, leave 14.86 grains of dry sulphate of lithium, which, when 
redissolved in distilled water, yields no precipitate with oxalate of 
ammonium or solution of lime,” indicating absence of salts of 
calcium and aluminium. Citrate of lithium should yield by incin- 
eration 52.8 per cent, of white carbonate of lithium. 
Urate of lithium* is more soluble than urate of sodium ; hence 
lithium preparations are administered to gouty patients in the hope 
that urate of sodium, with which such systems are loaded, may be 
converted into urate of lithium and removed. 
In chemical position lithium stands between the alkaline and the 
alkaline-earth metals, its hydrate, carbonate, and phosphate being 
slightly soluble in water. The double chloride of platinum and 
lithium also is soluble in water. Its atom is univalent, I/. 
Analytical Reaction.—Moisten the end of a platinum wire 
with solution of a minute particle of solid lithium salt, and in- 
troduce it into the flame of a Bunsen burner or other slightly 
colored flame (spirit-lamp or blowpipe-flame); a magnificent 
crimson tinge is imparted. 
The light thus emitted by ignited lithium vapor is of a purer 
scarlet than that given by strontium, the next element. When the 
flames are examined by spectral analysis (physically analyzed by a 
prism), the red rays are, in the case of strontium, found to be asso- 
ciated with blue and yellow, neither of which is present in the 
lithium light, blue lithium rays only appearing at temperatures 
much higher than those of ordinary air-gas flames. 
Symbol Sr. Atomic weight 87.4. 
STRONTIUM. 
Source.—Strontium is not widely distributed in nature, but the 
carbonate (SrC03) known as strontianite, and the sulphate (SrS04), 
known as celestine (from eoelum, the sky, in allusion to its occasional 
bluish color), are by no means rare minerals. 
Salts of strontium are not employed in medicine. They are 
chiefly used by firework-manufacturers in preparing red fire. The 
color they impart to flame is a beautiful crimson—ignited strontium 
vapor emitting red rays, as already explained. Nitrate of strontium 
(Sr2NO.,) is best for pyrotechnic compositions, its oxygen enabling 
it to burn freely when mixed with charcoal, sulphur, etc. It, or any 
salts, may be obtained by dissolving the carbonate in the appropri- 
* Urates will be considered subsequently in connection with uric 
acid. 225 
STRONTIUM. 
ate acid, or by igniting the cheaper sulphate with coal, wdiereby 
sulphide (SrS) is produced, and dissolving this in acid. 
The position of strontium among the chemical elements is between 
barium and calcium ; its sulphate is very sparingly soluble in water. 
Its atom, like those of barium and calcium, is bivalent (Sr"). 
Analytical Reactions ( Tests). 
First Analytical Reaction.—To a solution of a strontium 
salt (Sr2NO:i or SrCl2) add carbonate of ammonium; a white 
precipitate of carbonate of strontium (SrCO:j) falls. 
Second Analytical Reaction.—To a solution of a strontium 
salt add sulphuric acid previously so diluted that it will not 
precipitate calcium salts, or add an equally dilute solution of 
any sulphate (e. y., that of calcium itself); a white precipitate 
of sulphate of strontium (SrS04) falls, The formation of this 
precipitate is promoted by stirring and setting the liquid aside 
for some time. 
Barium is precipitated immediately under similar circumstances 
Third Analytical Reaction.—To a dilute solution of a stron'- 
tium salt add yellow chromate of potassium ; no precipitate 
falls. 
Barium may he separated from strontium by chromate of potas- 
sium, that reagent at once precipitating barium from aqueous or 
acetic solutions. The value of the reaction is enhanced if the solu- 
tions be dilute and if acetic acid or acetate of ammonium be pres- 
ent, chromate of strontium being far more soluble in such fluids 
than in water (Ransom). It is also more soluble in cold than in 
hot fluids. 
Fourth Analytical Reaction.—Insert a fragment of a stron- 
tium salt in the blowpipe-flame, or other equally colorless flame, 
or hold the end of a platinum wire dipped into a strontium so- 
lution in the flame ; a crimson color is imparted. 
Other Analytical Reactions.—Alkali-metal phosphates, ar- 
seniates, and oxalates give white insoluble precipitates with 
strontium as with barium and calcium. Strontium, like 
calcium, but unlike barium, is not precipitated by hydrofluo- 
silicic acid. 
Cerium. Ce. At. wt. 22.—This element occurs in the mineral 
cerite (a silicate of iron, calcium, and the three rare metals, cerium, 
lanthanum, and didymium); also occasionally as impure fluoride, 
carbonate, and phosphate. The oxalate of cerium, a white granular 
powder, is the only official salt; it may be obtained from cerite by 
boiling the powdered mineral in strong hydrochloric acid for several 
hours, evaporating, diluting, and filtering to separate silica; adding 
ammonia to precipitate hydrates of all the metals except calcium; 226 
RARER METALLIC RADICALS, 
filtering off, washing, redissolving in hydrochloric acid, and adding 
oxalic acid to precipitate oxalate of cerium. The preparation will 
still contain oxalates of lanthanum and didymium ; it is therefore 
strongly calcined, the resulting oxides of lanthanum and didymium 
dissolved out to some extent by boiling with a concentrated solution 
of chloride of ammonium, the residual oxide of cerium dissolved in 
boiling hydrochloric acid, and oxalate of ammonium added to pre- 
cipitate white, granular oxalate of cerium (Ce2///3C204,9II20). Ac- 
cording to Hartley the precipitated hydrates are treated with chlorine, 
by which ceric hydrate is left insoluble and the other hydrates con- 
verted into soluble hypochlorites. 
Oxalate of cerium (Cerii Oxalas, U. S. P.) is decomposed at a 
dull red heat, 48 per cent, of a yellow, or, more generally, a salmon- 
colored, mixture of oxides remaining ; usually the didymium present 
gives the ignited residue a reddish or reddish-brown color ; it is then 
soluble in boiling hydrochloric acid (without effervescence; indica- 
ting, indirectly, absence of earthy and other carbonates or oxalates), 
and the solution gives, with excess of a saturated solution of sul- 
phate of potassium, a crystalline precipitate of double sulphate of 
cerium and potassium. Alumina mixed with oxalate of cerium may 
be detected by boiling with solution of potash, filtering, and adding 
excess of solution of chloride of ammonium, when a white flocculent 
precipitate of hydrate of aluminium will be obtained. Oxide of zinc 
is revealed on boiling in potash and adding sulphide of ammonium, 
when white sulphide of zinc falls. The oxalic radical is recognized 
by neutralizing the potash solution by acetic acid and adding chloride 
of calcium; white oxalate of calcium is then precipitated; this pre- 
cipitate, though insoluble in acetic, should be wholly dissolved by 
hydrochloric acid. Acid or neutral cerium solutions give with 
acetate of sodium and peroxide of hydrogen a brownish-red color 
(Hartley). 
According to H. G. Greenish, most samples of oxalate of cerium 
have as impurities traces of lead, iron, and magnesium. 
MANGANESE. 
Symbol Mn. Atomic weight 54. 
Source.—Manganese is a constituent of many minerals, and as 
black oxide, or dioxide, or binoxide (Mn02) (Mangani Oxidurn 
Nigrum, U. S. P., “containing not less than 66 per cent, of pure 
oxide, Mn02”), or pyrolusite (from ttvp, pur, fire, and 'Avoir, lusis, a 
loosing or resolving, in allusion to the readiness with which it is 
split up by heat into a lower oxide and oxygen), occurs frequently 
in abundance in the south-west of England, Aberdeenshire, and most 
of the countries of Europe. It is met with as a steel-gray mass of 
prismatic crystals or in black shapeless lumps. 
The chemical position of manganese is close to iron and three 
other metals still to be considered—cobalt, nickel, and chromium. 
Its atom apparently has sexivalent affinities, as seen in manganate 
of potassium, (K2Mn04) ; but commonly it is quadrivalent (MnIV) or 
bivalent (Mnr/). MANGANESE. 
227 
Uses.—Metallic manganese is only used in alloy writh iron in the 
manufacture of some varieties of steel. The black oxide is an im- 
portant agent in the production of chlorine, the preparation of green 
and red disinfecting manganates, purple glass, and black glazes for 
earthenware. 
Reactions having both Synthetical and Analytical Interest. 
First Reaction.—Boil a few grains of black oxide of manga- 
nese with some drops of hydrochloric acid until chlorine ceases 
to be evolved; add water, and filter; the filtrate is a solution 
of manganous chloride (MnCl2). 
This is the reaction commonly applied in the preparation of chlo- 
rine gas. It is also a ready method of preparing a manganous salt 
for analytical experiments. Coupled with the application of re- 
agents to the filtrate, the reaction is that by which a black powder 
or mineral would be recognized as black oxide of manganese. Black 
oxide of manganese dissolves in cold hydrochloric acid, forming 
a dark-brown solution of a higher chloride or chlorides, MnCl3, 
Mn.2Cl7, or, possibly, MnCl4. 
Second Reaction.—Heat a particle of a manganese compound 
with a grain or two of carbonate and hydrate of potassium and 
a fragment of nitrate or chlorate of potassium on platinum foil 
in the blowpipe-flame ; a green mass containing manganate of 
potassium (K.2Mn04) results. Boil the foil in a little water; 
the green manganate dissolves and soon changes to solution of 
the purple permanganate of potassium (K2Mn208). 
Mn02 + 4IIC1 = MnCl, + 2H,0 + Cl2. 
This is a delicate analytical test for manganese. 
The reaction is similar to that by which permanganate of potas- 
sium (Potassii Permanganas, U. S. P.) is prepared for use in vol- 
umetric analysis. Equations showing the exact action which occurs 
in making the salt according to the process of the British Pharma- 
copoeia have already been given in connection with the compounds 
of potassium (vide p. 76). The proportions of ingredients and details 
of the operation are as follows :— 
Reduce 3£ parts (for experiment each “part” may be oz.) of 
chlorate of potassium to tine powder, and mix it with 4 of black 
oxide of manganese; put the mixture into a porcelain basin, and 
add to it 5 parts of solid caustic potash, previously dissolved in 4 
parts of water. Evaporate to dryness, stirring diligently to prevent 
spirting. Pulverize the mass, put it into a covered Hessian or 
Cornish crucible, and expose it to a dull red heat (not higher) for 
an hour (20 or 30 minutes for quantities of 1 or 2 oz.), or till it has 
assumed the condition of a semi-fused mass. Allow to cool, pulver- 
ize, and boil writh about 30 parts of water. Let the insoluble matter 
subside, decant the fluid, boil again with about 10 parts of water, 
again decant, neutralize the united liquors accurately with diluted 228 
RARER METALEIC RADICALS. 
sulphuric acid (or, better, carbonic acid gas), and evaporate till a 
pellicle forms. Set aside to cool and crystallize. Drain the crystal- 
line mass, boil it in 6 parts of water, and strain through a funnel 
the throat of which is slightly obstructed by a little asbestos or 
gun-cotton. Let the fluid cool and crystallize, drain the dark 
purple slender prismatic crystals, and dry them by placing under 
a bell-jar over a vessel containing sulphuric acid. 
Instead of converting the manganate into permanganate by ebul- 
lition, by which one-third of the manganate is lost, Stadeler recom- 
mends chlorine to be passed through the cold solution until the 
green color is entirely changed to purple. 
Solutions of the manganates of potassium and sodium are in com- 
mon use as disinfectants under the name of Condy’s Fluid. They act 
by oxidizing organic matter, the manganic or permanganic radical 
being reduced to black manganic oxide, or even a lower oxide. The 
reason for using asbestos instead of paper in filtering the solutions 
will now be understood. 
The changes in color which the green mass of the above process 
undergoes when dropped into warm wrater procured for it the old 
name of mineral chameleon. 
Third Reaction.—Make a borax bead by heating a fragment 
of the salt on the looped end of a platinum wire in the blow- 
pipe-flame until a clear transparent globule is obtained. Tlace 
on the bead a minute portion of a manganese compound, or 
touch it with a drop of solution. Again fuse the borax, using 
the point of the flame; a bead of a violet or amethystine tint 
is produced. 
This is a good analytical reaction. It has also synthetical inter- 
est, illustrating the use of black oxide of manganese in producing 
common purple-tinted glass. 
Expose the bead to the reducing part of the flame, the part 
nearer to the blowpipe, where there are highly heated hydro- 
carbon gases greedy of oxygen ; the color disappears. 
This is owing to the reduction of the manganic compound to a 
manganous condition, in which it no longer possesses peculiar color- 
ing-power. This action also illustrates the use of black oxide of 
manganese in glass-manufacture. Glass when first made is usually 
of a green tint, owing to the presence of ferrous impurities; the 
addition of manganic oxide to the materials converts the ferrous 
into ferric compounds, which have comparatively little colorific 
power, it itself being thereby reduced to manganous oxide, which 
also gives but little color. If excess of manganic oxide be added, a 
purple tint is produced. 
Fourth Reaction.—Through a solution of a manganous salt 
acidified by hydrochloric acid pass sulphuretted hydrogen; no 
Reactions having Analytical Interest ( Tests'). MANGANESE. 
229 
decomposition occurs. Add ammonia ; the sulphydrate of am- 
monium thus formed causes the precipitation of a yellowish- 
pink or flesh-tinted precipitate of manganous sulphide (MnS) 
in a hydrous state. 
This reaction is characteristic, sulphide of manganese being the 
only flesh-colored sulphide known. The salt used may be the 
manganous chloride obtained in the first reaction; but such crude 
solutions usually give a black precipitate with sulphydrate of am- 
monium, owing to the presence of iron. The latter element may be 
precipitated, however, on adding excess of ammonia (and rapidly 
filtering; oxygen will be absorbed and most of the manganese also 
precipitated) or on boiling the manganous solution with a very little 
carbonate of sodium, which attacks the ferric salt in preference to 
the manganous. Pure manganous chloride may be similarly ob- 
tained on boiling the impure solution with manganous carbonate; 
the latter decomposes the ferric chloride with production of ferric 
hydrate and more manganous chloride, and evolution of carbonic 
acid gas. 
To the recently precipitated manganous sulphide add acetic 
acid ; it is dissolved. 
This solubility enables manganese to be separated from nickel, 
cobalt, and zinc, whose sulphides are insoluble in weak acetic acid. 
To express the fact in another way—manganese is not precipitated 
by sulphuretted hydrogen from a solution containing free acetic acid 
only. 
Fifth Reaction.—To solution of manganous salt add am- 
monia; a white precipitate of manganous hydrate (Mn2HO) 
falls. Add excess of ammonia ; some of the precipitate is dis- 
solved, and may be detected in the quickly filtered solution by 
sulphydrate of ammonium. But both precipitate and solution 
rapidly absorb oxygen, the manganese passing into a more 
highly oxidized condition in which it is insoluble in ammonia. 
The fixed alkalies give a similar precipitate insoluble in excess. 
The precipitate rapidly absorbs oxygen, becomes brown, and grad- 
ually passes into a higher oxide. 
Sixth Reaction.—Heat a little black oxide of manganese in 
a test-tube with sulphuric acid; oxygen is evolved and sul- 
phate of manganese formed (Mangani Sulphas, MnS04,4H20, 
U. S. P.) ; add water, boil, filter, evaporate, and set aside to 
crystallize. Larger quantities are made in a similar manner. 
Sulphate of manganese (MnS04,5H20) occurs in colorless or pale 
rose-colored, transparent crystals, which, when deposited from a solu- 
tion at a temperature between 68° and 86°, have the form of right 
rhombic prisms, and contain four molecules of water (U. S. P.). 
This salt is very soluble in water. Other sulphates containing 1, 230 
RARER METALLIC RADICALS. 
2, 3, and 9 of water are known. The solution is not colored by 
tincture of nutgall (a black shows iron), but affords with caustic 
alkalies a white precipitate (Mn2HO), which, by exposure to the air, 
soon absorbs oxygen, and becomes brown. Sulphydrate of ammonium 
throws down a flesh-colored precipitate (MnS), and ferrocyanide of 
potassium a white one (Mrql'cy). 
Many other reactions occur between manganese salts and va- 
rious reagents, but are of no particular synthetical or analyt- 
ical interest. 
A good method proposed by Crum, for detecting minute 
quantities of manganese, consists in adding dilute nitric acid 
and either red lead or the puce-colored oxide or peroxide of 
lead to the solution, and then boiling; a red tint, said to be 
due to permanganic acid, is imparted to the liquid. 
Symbol Co. Atomic weight 58.9. 
COBALT. 
Source.—Cobalt occurs sparingly in nature as the arsenide 
(CoAs2), or tin-white cobalt, and occasionally as a double arsenide 
and sulphide (CoAs2,CoS2), or cobalt glance (from glanz, brightness, 
in allusion to its lustre). 
Uses.—Its chief use is in the manufacture of blue glass, the color 
of which is due to a compound of cobalt. Cobalt is also the coloring 
constituent of smalt (from smelt, a corruption of melt), a finely-ground 
sort of glass, used as a blue pigment by paper-stainers and others, 
and employed also by laundresses to neutralize the yellowish ap- 
pearance of washed linen. 
The salts of cobalt may be obtained from the oxide (CoO), and the 
oxide from zaffre, a mixture of sand and roasted ore. 
Quantivalence.—The atom of cobalt often exhibits quadrivalent 
affinities, but still more often exerts only bivalent powers (Co//). 
Cobalt has analytical relations with zinc, nickel, and manganese, 
and may be regarded as a member of the iron group. 
Analytical Reactions (Tests'). 
First Analytical Reaction.—Pass sulphuretted hydrogen 
through a solution of a salt of cobalt—the chloride (CoCl2) or 
nitrate (Co2N03), for example; no decomposition occurs. Add 
ammonia; the sulphydrate of ammonium thus formed causes 
the precipitation of black sulphide of cobalt (CoS). 
The moist precipitate slowly absorbs oxygen from the air, becom- 
ing converted into sulphate of cobalt (CoSOJ. 
Second Analytical Reaction.—Add ammonia gradually to a 
cobalt solution ; a blue precipitate of impure hydrate of cobalt 
(Co21IO) falls. Add excess of ammonia; the precipitate is NICKEL 
231 
dissolved, yielding a liquid somewhat more reddish-brown than 
the original solution. 
A similar precipitate is given by the fixed alkalies, insoluble in 
excess. 
Third Analytical Reaction.—Make a borax bead by heating 
a fragment of the salt on the looped end of a platinum wire in 
a blowpipe-flame until a clear transparent globule is obtained. 
Place on the bead a minute portion of a cobalt compound, or 
touch it with a drop of solution. Again fuse the borax ; a 
blue bead results. 
This is a delicate test for cobalt. From what has previously been 
said, it will be seen that this experiment has also considerable syn- 
thetical interest. 
Fourth Analytical Reaction.—To a solution of a salt of co- 
balt add two or three drops of hydrochloric acid, then excess 
of solution of cyanide of potassium, and boil for ten minutes; 
oxygen is absorbed, and cobalticyanide of potassium (K6Co2Cy,2) 
formed. Add hydrochloric acid, and boil the mixture (in a 
fume-cupboard, to avoid inhalation of any hydrocyanic acid) ; 
the excess of cyanide of potassium is thus decomposed, but the 
cobalticyanide is unaffected. Now add excess of solution of 
potash ; the cobalticyanide of potassium is decomposed, but the 
cobalt remains dissolved in the alkaline liquid. 
Nickel under similar circumstances is precipitated, the reaction 
thus affording means of separating these closely allied metals from 
each other. 
Other Reactions between a cobalt solution and different re- 
agents may be performed, and various precipitates obtained ; 
but these have no special analytical interest. 
Invisible Ink.—Many salts of cobalt containing water of 
crystallization are light red, the anhydrous more or less blue. 
Prove this by writing some words on paper with a solution of 
chloride of cobalt sufficiently dilute for the characters to be in- 
visible when dry; hold the sheet before a fire or over a flame; 
the letters at once become visible, distinct, and of a blue color. 
Breathe on the words, or set the sheet aside for a while; the 
characters are once more invisible, owing to absorption of moist- 
ure. Hence solution of chloride of cobalt forms one of the 
so-called sympathetic inks. 
Symbol Ni. Atomic weight 58. 
NICKEL 
Nickel is, chemically, closely allied to cobalt, the ores of the two 
metals being commonly associated in nature. Indeed, it is from 232 
RARER METALLIC RADICALS. 
speiss, an arsenio-sulphide of nickel obtained in the manufacture 
of smalt, a pigment of cobalt already mentioned, that most of 
the nickel met with in commerce is obtained. It is much used in 
the preparation of the white alloy known as German or nickel 
silver. 
Quantivalence.—Nickel exerts bivalent activity (Ni//) in its 
ordinary compounds. Its salts and their solutions are usually 
green. They are chiefly made, directly or indirectly, from the 
metal itself. 
Analytical Reactions (Tests'). 
First Analytical Reaction.—Pass sulphuretted hydrogen 
through a solution of a salt of nickel—chloride (NiCl2), nitrate 
(Ni2N03), or sulphate (NiS04); no decomposition occurs. 
Add ammonia; the sulphydrate of ammonium thus formed 
causes the precipitation of black sulphide of nickel (NiS). 
Note.—When sulphate of nickel is precipitated by the direct addi- 
tion of the common yellow solution of sulphydrate of ammonium, 
which always contains free sulphur, there is much difficulty in filter- 
ing the mixture, owing to the slight solubility of sulphide of nickel 
in the reagent and the formation of some sulphate of nickel (NiS04), 
oxygen being absorbed from the air by the sulphide. This may be 
avoided by warming the mixture and using freshly-made sulphydrate 
of ammonium, in which the sulphide of nickel is insoluble; or, where 
practicable, the salt of nickel may be precipitated from an ammo- 
niacal solution by sulphuretted hydrogen. 
Second, Analytical Reaction.—Add ammonia drop by drop 
to a nickel solution ; a pale-green precipitate of hydrate of 
nickel (Ni2HO) falls, especially on boiling the mixture. Add 
excess of ammonia; the precipitate dissolves, yielding a bluish 
rather than the original green-colored solution. 
A similar precipitate is given by the fixed alkalies, insoluble 
in excess. 
Third Analytical Reaction.—Nickel salts color a borax bead, 
when hot, a reddish-yellow tint; the reaction is not very ser- 
viceable analytically. 
Fourth Analytical Reaction.—To a solution of a salt of 
nickel add solution of cyanide of potassium ; cyanide of nickel 
(NiCy2) is precipitated. Add excess of solution of cyanide 
of potassium ; the precipitate is dissolved with formation of 
double cyanide of nickel and potassium (NiCy2,2KCy). Next 
add hydrochloric acid, and boil the mixture (in a fume-cup- 
board), adding a little hydrochloric acid from time to time 
until all smell of hydrocyanic acid has disappeared. Lastly, 
add excess of solution of potash; hydrate of nickel is precipi- 
tated. NICKEL. 
233 
Qualitative Separation of Cobalt and Nickel. 
The foregoing reaction serves for the separation of nickel from 
cobalt. On adding excess of hydrochloric acid to a solution contain- 
ing the two metals, together with cyanide of potassium, a precipi- 
tate of cyanide of nickel and cobalticyanide of nickel occurs. By 
ebullition with excess of hydrochloric acid the cyanide of nickel is 
decomposed, chloride of nickel going into solution. On then adding 
excess of potash, hydrate of nickel is precipitated. The cobalticy- 
anide of nickel is not decomposed by the acid; but is by the alkali, 
its cobalt going into solution and its nickel remaining insoluble as 
hydrate. 
After filtering off the nickel, cobalt is detected in the filtrate by 
evaporating to dryness and testing the residue with borax in the 
blowpipe-flame. 
W. R. Dunstan thus modifies this process:— 
To the acidified solution containing the two metals potassium 
cyanide is added in excess until a clear solution is obtained. To a 
portion of this liquid a few drops of yellow ammonium sulphide are 
added ; a dark-red coloration indicates cobalt. This reaction is very 
characteristic, and is not interfered with by the presence of nickel. 
The solution does not give the reaction after exposure to the air or 
after ebullition. The remainder of the solution is boiled for a few 
minutes, and when cool hydrochloric acid added in excess; if both 
metals are present a dense bluish-white precipitate occurs. The 
solution is boiled for some time till free from hydrocyanic acid, the 
precipitate remaining insoluble, which is a sure indication of the 
presence of both metals. To this liquid containing the precipitate 
large excess of potassium hydrate is added. The precipitate of 
nickelous cobalticyanide disappears, and is replaced by a pale-green 
flocculent precipitate of nickelous hydrate. 
The reducing action of glycerin on nickelic hydrate (Ni/>IIO), 
and the absence of any similar action on cobaltic hydrate affords 
another method of separating the metals. (See Pharmaceutical 
Journal, May 31, 1879.) 
Another Process.—To any solution containing cobalt and 
nickel add excess of ammonia, and then enough solution of 
ferridcyanide of potassium to dissolve any precipitate. If 
cobalt be present a reddish-brown color is produced in the 
liquid, due to the formation and solution of ferridcyanide of 
cobalt. Now add solution of ferrocyanide of potassium; a 
whitish precipitate of ferrocyanide of nickel appears, either at 
once, or, if the liquid is very weak, on partially neutralizing 
the free ammonia by hydrochloric acid. The ammonia must 
not be entirely neutralized by acid, nor enough acid added to 
decompose the reddish ferridcyanide of cobalt. If these pre- 
cautions be not observed, a greenish-white precipitate of ferro- 
cyanide of cobalt may be formed, and be mistaken for the 
ferrocyanide of nickel. 234 
RARER METALLIC RADICALS. 
The value of this method (Skey and Davies) turns on the 
facts that ferrideyanide of nickel is not a colored body, while 
ferrideyanide of cobalt is reddish-brown, and that ferrideyano- 
gen has apparently, in ammouiacal solution, greater affinity for 
cobalt than for nickel, while ferrocyanogen has, apparently, 
greater affinity for nickel than for cobalt. The formulae of 
these so-called ferrocyanides and ferrideyanides of cobalt and 
nickel have not been definitely ascertained. 
Other reactions between a nickel solution and various re- 
agents give, in many cases, insoluble precipitates which, from 
their green color, are occasionally useful in distinguishing nickel 
from allied elements. 
CHROMIUM. 
Source.—The chief ore of chromium is chrome ironstone, a mix- 
ture of the oxides of the metals (Fe0,Cr203), occurring chiefly in 
the United States and Sweden. In constitution it seems to resemble 
magnetic iron ore (Fe0,Fe203). 
Preparation of Red Chromate of Potassium.—On roasting the 
powdered ore with carbonate of potassium and nitre, yellow chro- 
mate of potassium (K2Cr04) is obtained ; the mass, treated with acid, 
yields red or bichromate (K2Cr04,Cr03) (Potassii Bichromas, U. S. 
P.); from this salt other chromates are prepared, and by reduction, 
as presently explained, the salts of chromium itself. The yellow 
and orange chromates of lead are largely used as pigments. 
Note on Constitution.—Red chromate of potassium is a somewhat 
abnormal salt, containing, probably, neutral chromate associated 
with chromic anhydride. The value of chromates as chemical 
reagents is alluded to in connection with chromate of barium (p. 
102). Heated strongly in a crucible, red chromate of potassium 
splits up into yellow chromate, glistening oxide of chromium, and 
oxygen. 
Quantivalence.—Chromium stands in close chemical relation to 
iron, aluminium, and manganese. Its atom is sexivalent if the for- 
mula of the fluoride (CrFs) be correct. Like iron and aluminium, 
it is trivalent, as seen in chromic chloride (Cr2Cl6), but sometimes 
exerts only bivalent activity, as in chromous chloride (CrCl2). 
Symbol Cr. Atomic weight 52.4. 
Passage of Chromium from the Acidulous to the Basylous 
Side of Salts.—Through an acidified solution of red chromate 
of potassium pass sulphuretted hydrogen ; sulphur is deposited, 
and a green salt of chromium remains in solution, chloride 
(Cr2Cl6) if hydrochloric acid be used, and sulphate (Cr23S04) 
if sulphuric be the acid employed. Boil the liquid to expel 
excess of sulphuretted hydrogen, filter, and reserve the solution 
for subsequent experiments. (For an equation of this reaction, 
see p. 235.) 235 
CHROMIUM. 
Alcohol, sugar, or almost any substance which is tolerably liable 
to oxidation, will answer as well as sulphuretted hydrogen.. 
Sulphate of chromium (Cr23S04), like sulphate of aluminium 
(A123S04), unites with alkali-metal sulphates to form alums, which 
resemble common alum both in crystalline form, and, as far as we 
know, in internal structure: they are of purple color. 
Reactions. 
Chromium as Chromic Acid, or other Chromate.—This is 
the state in which chromium will usually be met with, the most 
common salt being the red chromate or bichromate of potas- 
sium. Mix four volumes of a cold, saturated aqueous solution 
of red chromate of potassium with five of oil of vitrol; on 
cooling, chromic anhydride (Cr03), Acit/um Chromicum, U. S. 
P., separates in crimson needles. After well draining, the 
crystals may be freed from adhering sulphuric acid by washing 
once or twice with nitric acid: the latter may be removed by 
passing dried and slightly warmed air through a tube contain- 
ing tbe crystals. In contact with moisture chromic anhydride 
takes up water and forms solution of true chromic acid 
(H2Cr04). Chromic anhydride is a powerfully corrosive oxi- 
dizing agent. It melts between 350° and 374° I. 
The oxygen in chromic acid and other chromates, and in manga- 
nates, permanganates, black oxide of manganese, and puce-colored 
oxide of lead, is in a physically different state from that in peroxide 
of hydrogen, peroxide of barium, and similar compounds. On 
bringing chromic acid or the above acidified solution of red chro- 
mate of"potassium into contact with solution of peroxide of hydro- 
gen, a strong effervescence of oxygen ensues. According to Sehon- 
bein and Brodie the oxygen of chromic acid is in the negative or 
ozonic state, while that of peroxide of hydrogen is in the positive or 
so-called antozonic condition. Both are equally active, but neutral- 
ize each other, forming neutral or ordinary oxygen. 
In the analytical examination of solutions containing chro- 
mates, the chromium will always come out in the state of green 
chromic hydrate along with ferric hydrate and alumina, the 
prior treatment by sulphuretted hydrogen reducing the chro- 
mium in the molecule to the lower state, thus: 
K2Cr04,Cr03 + 8IIC1 + 3H2S s= Cr2Cl6 + 2KC1 
+ TILO + S3. 
Chromium having been found in a solution, its condition as 
chromate may be ascertained by applying to the original solu- 
tion salts of barium, mercury, lead, and silver. (See the vari- 
ous paragraphs relating to those metals.) RARER METAELIC RADICALS. 
Ba2N03 gives yellow BaCr04 with chromates. 
Hg22N03 “ red Hg2Cr04 “ 
AgN03 “ “ Ag2Cr04 “ 
££ ££ ££ Ag2Cr04,Cr0j with bichromates. 
Pb2C2II302 ££ yellow PbCr04 with both. 
Nitrate of barium does not completely precipitate bichromates, 
bichromate of barium being soluble in water; the chromate of ba- 
rium is insoluble in water or acetic acid, but soluble in hydro- 
chloric or nitric acid. Mercurous nitrate does not wholly pre- 
cipitate bichromates: mercuric nitrate or chloride only partially 
precipitates chromates, and does not precipitate bichromates. The 
mercurous chromate is insoluble, or nearly so, in diluted nitric acid. 
The silver chromates are soluble in acids and alkalies. Acetate of 
lead precipitates chromates and bichromates, acetic acid being set 
free in the latter case. 
A delicate reaction for dry chromates will he found in the 
formation of chlorochromic anhydride (Cr02Cl2). A small por- 
tion of the chromate is placed in a test-tube with a fragment 
of dry chloride of sodium and a drop or two.of oil of vitrol, 
and the mixture heated ; red irritating fumes of chlorochromic 
anhydride are evolved, and condense in dark-red drops on the 
side of the tube. 
Large quantities of pure distilled chlorochromic anhydride are 
obtained by the same reaction, the operation being conducted in a 
retort, with thoroughly dry materials, for the compound is decom- 
posed by water. It may be regarded as chromic anhydride in which 
an atom of oxygen is displaced by an equivalent quantity (two atoms) 
of chlorine. It is not used in medicine, but is of interest to the 
chemical student as being an illustration of a large class of similar 
bodies—chloro-acidulous or chloro-anhydrous compounds. The reac- 
tion is also occasionally serviceable for the detection of chlorides. 
Analytical Reactions of Chromium Salts ( Tests'). 
First Analytical Reaction.—To solution of a salt of chro- 
mium (chloride, sulphate, or chrome alum) add sulphydrate of 
ammonium; a bulky green precipitate of chromic hydrate 
(Cr.GHO), containing a large quantity of water (7 molecules, 
7H20), is precipitated. 
Cr2Cl6 + 6AmHS + 6H20 = Cr2GHO + GAmCl + GII2S. 
Second Analytical Reaction.—To solution of a chromium 
salt add ammonia; chromic hydrate is precipitated, insoluble 
in excess. 
Third Analytical Reaction.—To solution of a chromium salt 
add solution of potash or soda, drop by drop; chromic hydrate Trx. 
237 
is precipitated. Add excess of the fixed alkali; the precipitate 
is dissolved. Boil well the solution ; the chromic hydrate is 
reprecipitated. 
Iron, Chromium, and Aluminium Salts, chemically so alike, may 
be separated by this reaction. Ferric hydrate is insoluble in solu- 
tions of the fixed alkalies, cold or hot; chromium hydrate, soluble 
in cold but not in hot; hydrate of aluminium, in both. To a solu- 
ti< n containing all three metals, therefore, add potash or soda, stir, 
and filter; the iron is thrown out: boil the filtrate, and filter; the 
chromium is thrown out: neutralize the filtrate by acid, and then 
add ammonia; the aluminium is thrown out. Note, however, that 
ferric hydrate will prevent hydrate of chromium being dissolved by 
potash or soda if the ferric hydrate is in considerable excess. Before 
concluding that chromium is entirely absent, the 4th reaction should 
be performed. The hydrates of iron, chromium, and aluminium are 
insoluble in ammonia, and may therefore be easily separated from 
the hydrates of the somewhat analogous metals zinc, cobalt, nickel, 
and manganese. 
Fourth Analytical Reaction.—Add a salt of chromium (either 
of the above precipitates of chromic oxide or the dry residue of 
the evaporation of a few drops of a solution of a chromium 
salt) to a few grains of nitre and carbonate of sodium on plat- 
inum foil, and fuse the mixture in the blowpipe-flame ; a yellow 
mass of chromate of potassium and sodium (KNaCr04) is 
formed. Dissolve the mass in water, add acetic acid to de- 
compose excess of carbonate, and apply the reagents for chro- 
mates. 
This is a delicate and useful reaction if carefully performed. 
TIN. 
Symbol Sn. Atomic weight 117.7. 
Source.—The chief ore of tin is stannic oxide (Sn02), occurring 
in veins under the name of tinstone, or in alluvial deposits as stream- 
tin. The oldest mines are those of Cornwall. Much tin is now im- 
ported from Australia. 
Preparation.—The metal is obtained by reducing the roasted and 
washed ore by charcoal or anthracite* coal at a high temperature, 
and is purified by slowly heating, when the pure tin, fusing first, is 
run off, a somewhat less fusible alloy of tin with small quantities of 
arsenicum, copper, iron, or lead remaining. The latter is known as 
block tin ; the former heated till brittle and then hammered or let 
* Anthracite (from avQpaf, anthrax,, a burning coal) or stone coal differs 
from the ordinary bituminous or calcine/ coal in containing less volatile 
matter, and, therefore, in burning without flame. It gives a higher 
temperature, and from its non-caking properties is, in furnace opera- 
tions, more manageable than bituminous coal. 238 
RARER METALLIC RADICALS. 
fall from a height splits into prismatic fragments, resembling starch 
or columnar basalt, and is named dropped or grain tin. flood tin 
emits a crackling noise in bending, termed the cry of tin, caused by 
the friction of its crystalline particles on each other. 
Uses.—Tin is an important constituent of such alloys as pewter, 
Britannia metal, solder, speculum-metal, bell-metal, gun-metal, and 
bronze. It is very ductile, and may be rolled into plates or leaves, 
known as tinfoil, varying from to xttVtt an inch in thickness. 
Common tin foil, however, usually contains a large proportion of 
lead. The reflecting surface of looking-glasses was, formerly, always 
an amalgam of tin and mercury, produced by carefully sliding a 
plate of glass over a sheet of tin foil on which mercury had been 
rubbed, and then excess of mercury poured; but pure silver, de- 
posited from a solution, is now largely employed. Pins are made 
of brass wire, on which tin is deposited. Tin plate, of which com- 
mon utensils are made, is iron alloyed with tin by dipping the acid- 
cleansed sheet into melted tin covered with oil, which, by dissolving 
any trace of oxide, or, perhaps, by preventing oxidation, enables 
the tin more completely to alloy with the iron. Tin tacks are in 
reality tinned iron tacks; a tin nail would be too soft to drive into 
wood. Tin may be granulated by melting and triturating briskly 
in a hot mortar, by shaking melted tin in a box on the inner sides 
of which chalk has been rubbed, or, in thin little bells or corrugated 
fragments (Granulated Tin, B. P.), by melting in a ladle and, as 
soon as fluid, pouring from the height of a few feet into water. 
Powdered tin has been used medicinally as a mechanical irritant to 
promote expulsion of worms. The hair of the pods of Kiwach or 
Cowhage (Hindustani) (Mucuna pruriens, P. I.) is almost the only 
medicine (excluding diluents and dentifrices) which acts in such a 
directly mechanical manner. 
The chemical position of tin among the metals is close to that of 
arsenicum and antimony. Its atom is quadrivalent and bivalent. 
The two classes of salts are termed stannic and stannous respec- 
tively. They are all made directly or indirectly from the metal 
itself. 
Reactions haying (a) Synthetical and (h) Analytical 
Interest. 
(a) Synthetical Reactions. 
Chloride of Tin. Stannous Chloride. 
First. Synthetical Reaction.—Warm a fragment of tin with 
hydroclilorous acid ; hydrogen escapes and solution of stannous 
chloride (SnCl2, perhaps Sn2Cl4) is formed. It may be retained 
for future experiments. 
One ounce of tin dissolved in three fluidounces of hydrochloric 
acid and one of water, and the resulting solution diluted to five fluid- 
ounces, constitutes the “ Solution of the Chloride of Tin.”—B. P. 
Solid Stannous Chloride.—By evaporation of the above solution TIN. 
239 
stannous chloride is obtainable in crystals (SnCl2,2II20). It is a 
powerful reducing agent, even a dilute solution precipitating gold, 
silver, and mercury from their solutions, converting ferric and cupric 
into ferrous and cuprous salts, and partially deoxidizing arsenic, 
manganic, and chromic acids. It absorbs oxygen from the air, and 
is decomposed when added to a large quantity of water unless some 
acid be present. It is used as a mordant in dyeing and calico- 
printing. 
Second Synthetical Reaction.—Through a portion of the so- 
lution of the stannous chloride of the previous reaction pass 
chlorine gas; solution of stannic chloride (SnCl4) is formed. 
Or add hydrochloric acid to the stannous solution, boil, and 
slowly drop in nitric acid until no more fumes are evolved; 
again stannic chloride results, lleserve the solutions for sub- 
sequent experiments. 
Perchloride of Tin. Stannic Chloride. 
Third Synthetical Reaction.—Boil a fragment of tin with 
nitric acid, evaporate to dryness, and strongly calcine the resi- 
due ; light buff-tinted stannic anhydride (Sn02) is produced. 
Heat the stannic anhydride with excess of solid caustic pot- 
ash or soda ; stannate of the alkali metal (K2Sn03 or Na2SnO:j) 
results. Dissolve the stannate in water, and add hydrochloric 
acid; white, gelatinous stannic acid (H2Sn03) is precipitated. 
Stannic acid is also obtained on adding an alkali to solution of 
stannic chloride: it is soluble in excess of acid or alkali. 
Stannic Oxide, or Anhydride, and Stannates, 
The product of the action of nitric acid on tin is also an acid, but 
from its insolubility in hydrochloric and other acids is different from 
ordinary stannic acid. It is termed metastannic acid (from /tera, 
meta, beyond), and probably has a composition expressed by the 
formula II10Sn5O15. (Vide Index, “Isomerism.”) It is also pro- 
duced on gentiy heating stannic acid:— 
5H2Sn03 — H10Sn5015 
Stannic 
acid. 
Metastannic 
acid. 
Metastannates have the general formula M2H8Sn5015. Both acids 
yield buff-colored stannic oxide or anhydride (Sn02) when strongly 
heated. The hitter is employed in polishing plate under the name 
of putty powder. Stannate of sodium (Na2Sn03,4H20) is used as a 
mordant by dyers and calico-printers under the name of tin pre- 
pare-liquor. 
(b) Reactions having Analytical Interest ( Tests'). 
Stannous or Stannic Salts.—Heat any solid tin compound 
with a mixture of cyanide of potassium and carbonate of so- 240 
RARER METALLIC RADICALS. 
dium on charcoal by the inner flame of the blowpipe. Glob- 
ules of tin separate, having, when cut by a knife, character- 
istic brightness and hardness. 
First Analytical Reaction.—Through a dilute solution of a 
stannous salt (stannous chloride, for example; see previous 
page) pass sulphuretted hydrogen gas; brown stannous sul- 
phide (SnS) is precipitated. Pour off' the supernatant liquid, 
add ammonia to the moist precipitate (to neutralize acid), and 
lastly yellow sulphydrate of ammonium solution ; the precipi- 
tate is dissolved. 
Aqueous solution of sulphydrate of ammonium becomes yellow 
when a day or two old, and then contains excess of sulphur, that 
element having become displaced by oxygen absorbed from the air; 
hence, in the above reaction, the stannous sulphide (SnS), in dis- 
solving, becomes stannic sulphide (SnS2); for the latter is pre- 
cipitated on decomposing the alkaline liquid by an acid. 
Second Analytical Reaction.—To solution of a stannous salt 
add solution of potash or soda; white stannous hydrate falls 
(Sn21iO). Add excess of the alkali; the precipitate dissolves. 
Boil the solution ; some of the tin is precipitated as blackish 
stannous oxide (SnO). 
Ammonia gives a similar precipitate, insoluble in excess. The 
alkaline carbonates do the same, carbonic acid gas escaping. 
STANNOUS SALTS. 
Third Analytical Reaction.—Through a solution of a stannic 
salt (stannic chloride, for example ; see page 239) pass sulphur- 
etted hydrogen gas; yellow stannic sulphide (SnS2) is precipi- 
tated. Pour off’ the supernatant liquid, and to the moist pre- 
cipitate add ammonia (to neutralize acid), and then sulphydrate 
of ammonium; the precipitate dissolves. 
Note.—In precipitating stannic sulphide the presence of too much 
hydrochloric acid must be avoided; the formation of the precipitate 
is also facilitated if the solution -be warmed. Stannic sulphide, like 
the sulphide of arsenicum and antimony, dissolves in a solution of 
alkaline sulphide or sulphydrate, with formation of definite crys- 
tallizable sulphostannates (M/.2SnS;i). 
Anhydrous stannic sulphide, prepared by sublimation, has a yel- 
low or orange lustrous appearance, and is used by decorators as 
hronzing-powder. It is sometimes termed mosaic gold. 
STANNIC SALTS. 
Fourth Analytical Reaction.—To solution of a stannic salt 
add potash or soda; white stannic acid falls (H2Sn03). Add GOLD. 
241 
excess of the alkali; the precipitate dissolves. Boil the mix- 
ture ; no reprecipitation occurs—a fact enabling stannic to be 
distinguished from stannous salts. 
Ammonia gives a similar precipitate, soluble, but not readily, in 
excess. The fixed alkali-metal carbonates do the same, carbonic 
acid gas escaping; after a time the stannic salt is again deposited, 
probably as stannate of the alkali metal. Carbonate of ammonium 
and acid carbonates of alkali metals give a precipitate of stannic 
acid insoluble in excess. 
Antidotes.—In cases of poisoning by tin salts (dyer’s tin liquor, 
e. g.), solution of carbonate of ammonium should be given. White 
of egg is also said to form an insoluble precipitate with compounds 
of tin. Vomiting should be speedily induced, and the stomach- 
pump quickly applied. 
GOLD 
Symbol Au. Atomic weight 196.2, 
Source.—Gold occurs in the free state in nature, occasionally in 
nodules or nuggets, but commonly in a finer state of division termed 
gold dust. 
Preparation.—Gold is separated from the sand, crushed quartz, 
or other earthy matter with which it may be associated, by agita- 
tion with water, when the gold, from its relatively greater specific 
gravity, falls to the bottom of the vessel first, the lighter mineral 
matter being allowed to run off with the water. From this rich 
sand the gold is dissolved out by mercury, the amalgam filtered, 
and afterwards distilled, when the mercury volatilizes and gold 
remains. The amalgamation may be much facilitated by the use 
of a small proportion of sodium, as already described in treating 
of silver. 
Pure gold is too soft for general use as a circulating medium. 
Gold coin is an alloy of copper and gold, that of Great Britain 
containing l of the former to 11 of the latter, or per cent, of 
copper, that of France, Germany, and the United States about 10 
per cent. Jeweller's gold varies in quality, every 24 parts containing 
18, 15, 12, or 9 parts of gold, the alloys being technically termed 
18, 15, 12, or 9 carat fine. Articles made of the better qualities are 
usually stamped by authority. Trinkets of inferior intrinsic worth 
are commonly thinly coated with pure gold by electro-deposition or 
otherwise. Gold leaf (U. S. P.), is nearly pure gold passed between 
rollers till it is about of an inch in thickness and then ham- 
mered between sheets of animal membrane, termed gold-beater’s 
skin and calf-skin vellum, till it is tsttWo or °f an inch in 
thickness. It may even be hammered till 280,000 leaves would be 
required to form a pile an inch thick. 
Gold Coinage.—The weight of gold is expressed in Great Britain 
in ounces troy and decimal parts of an ounce, and the metal is always 
taken to be of standard fineness (11 gold and 1 alloy) unless other- 
wise described. The degree of fineness of gold, as ascertained by 
assay, is expressed decimally, fine pure gold (“ gold free from metallic 242 
RARER METALLIC RADICALS. 
impurities,” B. P.) being taken as unity, or 1.000. Thus gold of 
British standard is said to be 0.9166 fine, of French standard 0.900 
fine. The legal weight of the sovereign is 0.2568 ounce of standard 
gold, or 123.274 grains. The weight came from one pound of stand- 
ard gold (5760 grains) being coined into 44J guineas. Gold coins 
are legal tender to any amount, provided that the weight of each 
sovereign does not fall below* 122.5 grains, or in the case of a half 
sovereign 61.125 grains; these are the “ least current” weights of 
the coins. 
Note.—In chemical analysis gold comes out among the sulphides 
of the metals precipitated by sulphuretted hydrogen; and of those 
sulphides, it, like the sulphides of tin, antimony, and arsenicum, is 
soluble in sulphydrate of ammonium. 
Quantivalence.—Gold is trivalent (Au///), but in some compounds 
univalent (Aux). 
Synthe'ical Reactions.—Place a fragment of gold (e. g.. gold 
leaf) in ten or twenty drops of aqua regia (a mixture of three 
parts of nitric and four or five of hydrochloric acid), and set 
the test-tube aside in a warm place ; solution of perchloride of 
gold or auric chloride (AuC13) results. When the metal is 
dissolved, evaporate nearly to dryness to remove most of the 
excess of fluid, dilute with water, and retain the solution for 
subsequent experiments. Sixty grains of gold treated thus, 
and the resulting chloride dissolved in five ounces of distilled 
water, constitute “ Solution of Chloride of Gold,” B. P. 
Reactions. 
Au2 + 2IINO3 + 6HC1 = 2AuC13 + 2N0 + 4II20. 
This reaction has analytical interest also; for in examining a sub- 
stance suspected to be or contain metallic gold, solution would have 
to be effected in the above way before reagents could be applied. 
Gold is insoluble in hydrochloric, nitric, and the weaker acids. 
Chloride of Gold and Sodium (A uri et Sodii Chloridum, U. S. P.) 
is u a mixture composed of equal parts of dry chloride of gold and 
chloride of sodium.” 
Analytical Reactions ( Tests). 
First Analytical Reaction.—Through a few drops of solution 
of an auric salt (the chloride, AuC13, is the only convenient 
one) pass sulphuretted hydrogen; brown auric sulphide (Au2S3) 
is precipitated. Filter, wash, and add yellow sulphydrate of 
ammonium solution ; the precipitate dissolves. 
Second Analytical Reaction.—To solution of a salt of gold 
add ferrous chloride or sulphate, and set the tube aside; metal- 
lic gold is precipitated, a ferric salt remaining in solution. 
This is a convenient way of preparing pure gold, or fine gold as 
it is termed, or of working up the gold residues of laboratory opera- PLATINUM. 
tions. The precipitate, after boiling with hydrochloric acid, washing 
and drying, may be obtained in a button by mixing with an equal 
weight of borax or acid sulphate of potassium and fusing in a good 
furnace. 
Third Analytical Reaction.—Add a few drops of dilute so- 
lutions of stannous and stannic chloride to a considerable 
quantity of distilled water; pour the liquid, a small quantity 
at a time, in a very dilute solution of auric chloride (AuCL,), 
well stirring; the mixture assumes a purple tint, and flocks of 
a precipitate known as the Purple of Caseins (from the name 
of the discoverer, M. Cassius) are produced. 
The same compound is formed on immersing a piece of tin foil in 
solution of auric chloride ; it is said to be a mixture of auric, aurous, 
stannic, and stannous oxides. It is the coloring agent in the finer 
varieties of ruby glass. 
PLATINUM. 
Source.—Platinum, like gold, usually occurs in nature in the free 
state, the chief sources of supply being Mexico, Brazil, and Siberia, 
it is separated from the alluvial soil by washing. 
Uses.—The chief use of platinum is in the construction of foil, wire, 
crucibles, spatulas, capsules, evaporating-dishes, and stills for the 
use of the chemical analyst or manufacturer. It is tolerably hard, 
fusible with very great difficulty, not dissolved by hydrochloric, nitric, 
or sulphuric acid, and only slightly affected by alkaline substances. 
It is attacked by aqua regia, with production of perchloride of plat- 
inum or platinic chloride (PtCl4). It forms fusible alloys with lead 
and other metals, and with phosphorus a phosphide, which easily 
melts. Neither of these substances, therefore, nor mixtures which 
may yield a metal, should be heated in platinum vessels. 
The chemical position of platinum among the elements is close to 
that of gold. Its atom is quadrivalent in some compounds, in others 
apparently bivalent (Pt//). The higher salts are termed platinic, the 
lower platinous. 
The specific gravity of platinum is 21.5; and that of iridium, an 
allied metal, 22.4. 
Symbol Pt. Atomic weight 194.4. 
Perchloride of Platinum. Platinic Chloride. 
Reactions. 
Synthetical Reaction.—Place a fragment of platinum in a 
little aqua regia and set the vessel aside in a warm place, add- 
ing more acid from time to time if necessary ; solution of per- 
cliloride of platinum (Ft Cl,) results. Evaporate the solution 
to remove excess of acid, and complete the desiccation over a 
water-bath. Dissolve the residue in water, and retain the solu- RARER METALLIC RADICALS. 
tion for subsequent experiments, and as a reagent for the pre- 
cipitation of salts of potassium and ammonium. 
A quarter of an ounce of platinum treated in the above manner, 
and the resulting chloride dissolved in five ounces of water, con- 
stitutes “ Solution of Perchloride of Platinum,” B. P., or 1 part of 
pure platinic chloride (PtCl4,5H20) dissolved in 20 of distilled water 
gives “ Test Solution of Platinic Chloride,” U. S. P. 
This reaction has analytical interest also; for in examining a sul>- 
stance suspected to be or to contain metallic platinum, solution would 
have to be thus effected before reagents could be applied. 
Analytical Reactions ( Tests). 
First Analytical Reaction.—Through a few drops of a solu- 
tion of a platinic salt (PtCl4 is the only convenient one), to 
which an equal quantity of solution of chloride of sodium has 
been added, pass sulphuretted hydrogen ; dark-brown platinic 
sulphide (PtS2) is precipitated. Filter, wash, and add sulphy- 
drate of ammonium; the precipitate dissolves. 
If chloride of sodium be not present in the above reaction, the pre- 
cipitated sulphide will contain platinous chloride, and may detonate 
if heated. 
Second Analytical Reaction.—Add excess of solution of car- 
bonate of sodium and some sugar to solution of perchloride of 
platinum and boil; a precipitate of metallic platinum falls. 
Platinum Black is the name of this precipitate. It possesses in 
a high degree a quality common to many substances, but largely 
possessed by platinum, namely, that of absorbing or occluding gases. 
In its ordinary state, after well washing and drying, it absorbs from 
the air and retains many times its bulk of oxygen. A drop of ether 
or alcohol placed on it is rapidly oxidized, the platinum becoming 
hot. This action may be prettily shown by pouring a few drops of 
ether into a beaker (one having portions of the top and sides broken 
off answers best), loosely covering the vessel with a card, and sus- 
pending within the beaker a platinum wire, one end being attached 
to the card by passing through its centre, the other terminating in 
a short coil or helix near the surface of the ether; on now warming 
the helix in a flame and then rapidly introducing it into the beaker, 
it will become red hot, and continue to glow so long as there is ether 
in the vessel. In this experiment real combustion goes on between 
the ether vapor and the concentrated oxygen of the air, the products 
of the oxidation revealing themselves by their odor. 
Third Analytical Reaction.—To solution of perchloride of 
platinum add solution of chloride of ammonium ; a yellow 
granular precipitate of double chloride of platinum and ammo- 
nium (PtCl4,2AmCl) falls. When slowly formed in dilute so- 
lutions, the precipitate is obtained in minute orange prisms. CADMIUM 
245 
Chloride of potassium (KC1) gives a similar precipitate (PtCl4- 
2KC1). Platinic chloride having been stated to be a test for potas- 
sium and ammonium salts, the reader is prepared to find that potas- 
sium and ammonium salts are tests for platinic salts. The double 
sodium compound (PtCl42NaCl) is soluble in water. 
Collect the precipitate, dry, and heat in a small crucible; 
it is decomposed, and metal, in the finely divided state of 
spongy platinum, remains. 
3(PtCl42NHtCl) = 1% + 2NII.C1 + 16HC1 + 2N2. 
Heat decomposes the potassium salt into Pt + 2KC1 + Cl4, the 
chlorine escaping and the chloride of potassium remaining with the 
platinum. 
In working up the platinum residues of laboratory operations, the 
mixture should be dried, burnt, boiled successively with hydrochloric 
acid, water, nitric acid, water, then dissolved in aqua regia, excess 
of acid removed by evaporation, chloride of ammonium added, the 
precipitate washed with water, dried, ignited, and the resulting 
spongy platinum retained or converted into perchloride for use as a 
reagent for alkali metals. It is by this process that the native plat- 
inum is treated to free it from the rare metals palladium, rhodium, 
osmium, ruthenium, and iridium. The spongy platinum is converted 
into the massive condition by a refinement on the blacksmith's pro- 
cess of welding (German wellen, to join), or by fusing in a flame of 
pure oxygen and hydrogen gases, the oxyhydrogen blowpipe. 
Occlusion by Spongy Platinum.—Spongy platinum has great 
power of occlusion. A small piece held in a jet of hydrogen causes 
ignition of the gas, owing to the close approximation of particles of 
oxygen (from the air) and hydrogen. Dobereiner’s lamp is con- 
structed on this principle—the apparatus being essentially a vessel 
in which hydrogen is generated by the action of diluted sulphuric 
acid on zinc, and a cage for holding the spongy platinum. 
CADMIUM 
In most of its chemical relations cadmium (Cadmiumt, U. S. P.) 
resembles zinc. In nature it occurs chiefly as an occasional con- 
stituent of the ores of that metal. In distilling zinc containing 
cadmium, the latter, being the more volatile, passes over first. In 
analytical operations, cadmium, unlike zinc, comes down among the 
metals precipitated by sulphuretted hydrogen ; that is, its sulphide 
is insoluble in dilute hydrochloric acid, while sulphide of zinc is 
soluble. It is a white malleable metal nearly as volatile as mercury. 
Sp. gr. 8.7. 
Beyond the occasional employment of the sulphide as a pigment 
(jaune brillant), and the iodide in photography and medicine, cad- 
mium and its salts are but little used. The atom of cadmium is 
bivalent (Cd//). 
Symbol Cd. Atomic weight 111.8. 246 
RAKER METALLIC RADICALS. 
Reactions. 
Iodide of Cadmium. 
First Synthetical Reaction.—Digest together in a flask me- 
tallic cadmium, water, and iodine until the color of the iodine 
disappears; solution of iodide of cadmium (Cadmii Jodidum, 
B. P.) (Cdl2) remains. Pearly micaceous crystals may be ob- 
tained on evaporating the solution. 
This is the process alluded to in the British Pharmacopoeia. The 
salt is also employed, with other iodides, in iodizing collodion for 
photographic purposes. It melts when heated, and is soluble in 
water or spirit, the solution reddening litmus-paper. 
Sulphate of Cadmium. 
Second Synthetical Reaction.—Dissolve cadmium in nitric 
acid; pour the resulting solution of nitrate of cadmium 
(Cd2X():i) into a solution of carbonate of sodium; dissolve the 
precipitate of carbonate of cadmium (CdC03) in dilute sul- 
phuric acid, separate and crystallize. Sulphate of cadmium 
(CdS04) is a white crystalline salt soluble in water. 
First Analytical Reaction.—Through solution of a cadmium 
salt (Cdl2 or CdCl2) pass sulphuretted hydrogen; a yellow 
precipitate of sulphide of cadmium (CdS) falls, resembling in 
appearance arsenious, arsenic, and stannic sulphides. Add 
sulphydrate of ammonium ; the precipitate, unlike the sul- 
phides just mentioned, does not dissolve. 
Sulphides of cadmium and copper maybe separated by solution 
of cyanide of potasssium, in which sulphide of copper is soluble and 
sulphide of cadmium insoluble. 
Second Analytical Reaction.—To a cadmium solution add 
solution of potash; white hydrate of cadmium (Cd2HO) is 
precipitated, insoluble in excess of the -potash. 
Hydrate of zinc (Zn2HO), precipitated under similar circum- 
stances, is soluble in solution of potash ; the filtrate from the hy- 
drate of cadmium may therefore be tested for any zinc occurring as 
an impurity by applying the appropriate reagent—sulphydrate of 
ammonium. 
Before the blow-pipe-flame, on charcoal, cadmium salts give 
a brown deposit of oxide of cadmium (CdO). 
BISMUTH. 
Source.—Bismuth occurs in the metallic state in nature. It is 
freed from adherent quartz, etc. by simply heating, when the metal 
Symbol Bi. Atomic weight 210. BISMUTH. 
melts, runs off, and is collected in appropriate vessels. It is also met 
with in combination with other elements. Bismuth is grayish-white, 
with a distinct pinkish tinge. 
Uses.—Beyond the employment of some of its compounds in medi- 
cine, bismuth is but little used. Melted bismuth expands consider- 
ably on solidifying, and hence is valuable in taking sharp impres- 
sions of dies. It is a constituent of some kinds of type-metal and 
of pewter-solder. 
The position of bismuth among the metals is close to that of ar- 
senicum and antimony. Its atom is rarely quinquivalent (Biv), but 
in most compounds trivalent (Bir//). 
Reactions having (a) Synthetical and (6) Analytical 
Interest. 
(t») Reactions having Synthetical Interest 
First Synthetical Reaction.—To a few drops of nitric acid 
and an equal quantity of water in a test-tube add a little pow- 
dered bismuth, heating the mixture if necessary; nitric oxide 
(NO) escapes, and solution of nitrate of bismuth (Bi3NO;i) 
results. 
Nitrate of Bismuth. 
BL + 8HNO. = 2(Bi3N01) + 2NO + 411,0 
-—z 
Bis- 
muth. 
.1 
Nitric acid. 
Water. 
The solution evaporated gives crystals (Bi3N03,5H,0), any arsen- 
icum which the bismuth might contain remaining in the mother- 
liquor. Native bismuth commonly contains arsenicum, most of 
which is removed by roasting or by fusing two or three times with 
a tenth of its weight of nitre, or, finally, bv converting the metal 
into oxynitrate, as described in the next reaction, and reducing this 
with charcoal at a high temperature. 
To make nitrate of bismuth and other salts on a larger scale, 2 
ounces of the metal, in small fragments, are gradually added to a 
mixture of 4 fluidounces of nitric acid and 3 of water, and, when 
effervescence (due to escape of nitric oxide) has ceased, the mixture 
is heated for ten minutes, poured off from any insoluble matter, 
evaporated to 2 fluidounces to remove excess of acid, and then either 
set aside for crystals to form, or poured into a half gallon of water 
to form the oxynitrate of bismuth, or into a solution of 6 ounces of 
carbonate of ammonium in a quart of water to form the oxycarbo- 
nate, as described in the following reactions. The precipitates should 
be washed with cold water and dried at a temperature not exceeding 
150° F. Exposed in the moist state to 212° for any length of time, 
they undergo slight decomposition. 
Nitrate of 
bismuth. 
Nitric 
oxide. 
Subnitrate or Oxynitrate of Bismuth 
Second Synthetical Reaction.—Pour some of the,above solu- 248 
RARER METALLIC RADICALS. 
tion of nitrate into a considerable quantity of water; decompo- 
sition occurs, and oxynitrate of bismuth (BiONOa) in a hydrous 
state (Bi0N03,H.20) (Bismut hi Subuitras, U. S. P.) is precipi- 
tated :— 
Bi3N0:, + H20 = BiONO;j -f 2HN03 
Nitrate of 
bismuth. 
Water. 
Oxynitrate of 
bismuth. 
Nitric acid. 
Filter, and test the filtrate for bismuth by adding excess of 
carbonate of sodium ; a precipitate shows that some bismuth 
remains in solution. The following equation, therefore, prob- 
ably more nearly represents the decomposition :— 
5(Bi3N03) + 811,0 = 4(Bi0N03,H,0) + Bi3N03;8HN03 
Nitrate of 
bismuth. 
Water. 
Oxynitrate of 
bismuth. 
Nitrate of bismuth 
iu acid. 
Decomposition of nitrate of bismuth by water is the process of 
the Pharmacopoeia for the preparation of oxynitrate or “subnitrate” 
of bismuth for use in medicine. For this purpose the original metal 
must contain no arsenicum. In manufacturing the compound, 
therefore, before pouring the solution of nitrate into water, the 
liquid should be tested for arsenicum by one of the hydrogen tests •, 
if that element be present, the solution must be evaporated and only 
the deposited crystals be used in the preparation of the oxynitrate. 
For on pouring an arsenical solution of nitrate of bismuth into 
water, the arsenicum is not wholly removed in the supernatant 
liquid, unless the oxynitrate be redissolved and reprecipitated sev- 
eral times, according to the amount of arsenicum present. 
Subnitrate of bismuth is gradually decomposed by solution of 
alkaline carbonates; also by the bicarbonates, with production of 
carbonic acid gas, oxycarbonate of bismuth and nitrate of the alkali- 
metals being formed. It is used as a cosmetic under the name of 
Pearl-white (Blanc de Perle). 
Oxysalts of Bismuth—It will be noticed that the formula for sub- 
nitrate of bismuth (BiN04) does not accord with that of other 
nitrates, the characteristic elements of which are N03. Analogy 
would seem to indicate, however, that the fourth atom of oxygen 
has different functions from the three in the N03; for on pouring 
solution of chloride of bismuth (BiCl3) into water, oxychloride is 
produced (BiOCl) (a white powder used as a cosmetic, also in 
enamels, and in some varieties of sealing-wax). The bromide 
(BiBr3) and iodide (Bil3) similarly treated yield oxybromide (BiOBr) 
and oxyiodide (BiOI). The subnitrate (BiN04) is, therefore, prob- 
ably an analogous compound, an oxynitrate (BiONOg). The sulphate 
(Bi23S04) also decomposes when placed in water, giving what may be 
termed an oxysulphate (Bi,202S04). 
It is difficult to prove whether or not the water in the “ sub- 
nitrate” or hydrous oxynitrate of bismuth (Bi0N0;!,lI20) is an inte- 
gral part of the salt. If it is, the compound is simply the hydrato- 
nitrate (BiXO:j2H<>) of bismuth, BISMUTH. 
Oxide of Bismuth, 
Third Synthetical Reaction.—Boil subnitratc of bismuth 
with solution of soda for a few minutes; it is converted into 
yellowish oxide of bismuth (Bi.,Q,) (Bismuthi Oxidum, B. P.). 
2Bi0N03 + 2NaII0 == Bi203 + 2NaNO:i + H20 
Oxynitrate of 
bismuth. 
Hydrate of 
sodium. 
Oxide of 
bismuth. 
Nitrate of 
sodium. 
Water. 
Subcarbonate or Oxycarbonate of Bismuth. 
Fourth Synthetical Reaction.—To solution of nitrate of bis- 
muth add carbonate of ammonium or carbonate of sodium ; a 
white precipitate of hydrous oxycarbonate (2Bi202C03,H20) 
(Jiumuthi Snbcarhonas. U. S. P.) falls. 
2(Bi3N03) + Na2C03 = 6NaNO, + Bi202C03 + 200, 
Nitrate of 
bismuth. 
Carbonate of 
sodium. 
Nitrate of 
sodium. 
Oxycarbonate 
of bismuth. 
Carl>otiie 
acid gas. 
This compound may be regarded as similar in constitution to the 
oxysalts just described. In Bi./Xb one scarcely recognizes the cha- 
racteristic elements of carbonates ; but considering the preparation 
to be an oxycarbonate (Bi202C03), its relations to carbonates and 
oxides are evident. These subsalts may all be viewed as normal 
bismuth salts in which an atom of oxygen displaces an equivalent 
proportion of other acidulous atoms or radicals:— 
Chloride .... Bi3Cl Oxychloride . . BiOCl 
Bromide .... Bi3Br Oxybromide . . BiOBr 
Iodide Bi3I Oxyiodide . . BiOI 
Nitrate Bi3XOs Oxynitrate . . BiON03 
Sulphate .... Bi23S04 Oxysulphate. . Bi202S04 
Carbonate (unknown) Bi23C03 Oxycarbonate . Bi,02C03 
They may be viewed, in short, as salts in process of conversion to 
oxide; continue the substitution a little further, and each yields 
oxide of bismuth (Bi,0.,). They have also been considered to be 
salts of a hypothetical univalent radical, bismuthyl (BiO). 
Citrate of Bismuth. 
Fifth Synthetical Reaction.—Heat ten parts of oxynitrate of 
bismuth, seven of citric acid crystals, and thirty to forty of 
water together for a few minutes, until a drop of the mixture 
forms a clear solution with ammonia-water. Dilute the crystal- 
line mass with eight to ten times its volume of water, and set 
aside for a short time to let the citrate deposit; decant the 
clear liquid. Wash the crystalline sediment three or four times 
in a similar manner, drain and dry, either on a water-bath or 
by mere exposure. The yield is 13§ parts, showing that the 
salt is anhydrous, and that its formula is BiC6H507 (Ilother). 
This is the Bismuthi Citrus, TT. S. F. RARER METALLIC RADICALS. 
Sixth Synthetical Reaction.—Mix citrate of bismuth with 
water, add sufficient solution of ammonia to form a clear liquid, 
filter if necessary, evaporate to a syrupy consistence, spread on 
glass plates, and dry slowly until pearly scales are obtained. 
This is the Bismuthi et Ammonii Citrus, U. S. P. 
First Analytical Reaction.—Through solution of a bismuth 
salt (a slightly acid solution of nitrate, for example) pass sul- 
phuretted hydrogen ; a black precipitate of sulphide of bismuth 
(Bi2S8) falls. Add ammonia (to neutralize acid), and then sulphy- 
drate of ammonium ; the precipitate, unlike As2S3 and Sb283, is 
insoluble. 
Second Analytical Reaction.—Concentrate almost any acid 
solution of a bismuth salt and pour into water; a white salt is 
precipitated. 
This reaction is characteristic of bismuth salts; it has already 
been amply explained. The precipitate is distinguished from one 
formed by antimony under similar circumstances by being insol- 
uble in solution of tartaric acid. 
Third Anahj'ical Reaction.—To a solution of a bismuth salt 
add an alkali; hydrate of bismuth (Bi3HO) is precipitated, in- 
soluble in excess. 
Fourth Analytical Reac'ion.—A small quantity of the fol- 
lowing reagent, including both supernatant liquid and precip- 
itated scales, is transferred to a test-tube and gradually heated 
until solution takes place. Any liquid containing or supposed 
to contain bismuth is then added, and the whole allowed to cool. 
The separated scales will show a distinct change in color to 
dark orange or crimson according to the quantity of bismuth 
present. 
The test-reagent may be prepared by adding to a boiling solution 
of acetate of lead (half a grain to the ounce) solution of iodide of 
potassium in considerable excess. The solution of the iodide of 
lead precipitated is assisted by a little acetic acid. On cooling, 
iodide of lead is deposited in the characteristic scales. 
(h) Reactions having Analytical Interest ( Tests). 
The reader is again advised to trace out the exact nature of each 
of the foregoing reactions, chiefly by aid of equations or diagrams. 
343. Enumerate the fifteen metals, salts of which are frequently 
employed in pharmacy. 
QUESTIONS AND EXERCISES. QUESTIONS AND EXERCISES. 
251 
344. Mention the twelve rarer metals interesting to pharmacists. 
345. Name the sources and official compounds of lithium. 
346. Give an equation explanatory of the formation of Citrate of 
Lithium. 
347. What is the strength of Liquor Lithice Effervescens ? 
348. On what chemical hypothesis are lithium compounds admin- 
istered to gouty patients ? 
349. Describe the relation of lithium to other metals. 
350. What is the chief test for lithium? 
351. Write a paragraph on strontium, its natural compounds, chem- 
ical relations, technical applications, and tests. 
352. What are the formula; and properties of oxalate of cerium ? 
353. Name the commonest ores of manganese, and give an equa- 
tion descriptive of its reaction with hydrochloric acid. 
354. Explain the formation of permanganate of potassium, em- 
ploying diagrams or equations. 
355. In what manner do the manganates of potassium act as 
disinfectants ? 
356. What are the chief tests for manganese? 
357. What are the chief uses of the compounds of cobalt? 
358. I low are salts of cobalt analytically distinguished from those 
of nickel? 
359. Mention an application of nickel in the arts. 
360. What is the general color of nickel salts? 
361. State the method of preparation of red chromate of potas- 
sium. 
362. Give the formulae of red and yellow chromates of potassium. 
363. IIow is red chromate of potassium obtained? 
364. Describe the action of sulphuretted hydrogen on acidified 
solutions of chromates. 
365. What is the formula of chrome alum? 
366. Mention the chief tests for the chromic radical, and for 
chromium. 
367. How would you detect iron, chromium, and aluminium in a 
solution ? 
368. Define the terms tinstone, stream-tin, block-tin, grain-tin, 
tin-plate. 
369. Describe the position occupied by tin in relation to other 
metals. 
370. What is the difference between stannic acid and metastannic 
acid ? 
371. State the applications of tin in the arts. 
372. Mention the .chief tests for stannous and stannic salts. 
373. Name the best antidote in-cases of poisoning by tin solution. 
374. How is gold dust separated from the earthy matter with which 
it is naturally associated? 
375. How much pure gold is contained in English coin and in 
jeweller’s gold? 
376. State the average thickness of gold leaf. 
377. What is the weight of a sovereign? 
378. Explain the term “fineness” as applied to gold. 
of nickel? BARER METALLIC RADICALS. 
379. What effect is produced on gold by hydrochloric, nitric, and 
nitro-hydrochloric acids respectively ? 
380. By what reagents is metallic gold precipitated from solutions 
of its salts? 
381. How is Purple of Cassius prepared? 
382. Whence is platinum obtained? 
383. W7hy are platinum utensils peculiarly adapted for use in 
chemical laboratories ? 
384. How is perchloride of platinum prepared ? 
385. Name the chief tests for platinum. 
386. What is “ platinum black ” ? 
387. Describe an experiment demonstrative of the large amount of 
attraction for gases possessed by metallic platinum. 
388. How is “spongy platinum” produced? 
389. By what process may the metal be recovered from platinum 
residues ? 
390. What is occlusion in chemistry ? 
391. In what condition does cadmium occur in nature? 
392. By what process may Iodide of Cadmium be prepared ? and 
in what form is it used in medicine ? 
393. Mention the chief test for cadmium. 
394. Distinguish sulphide of cadmium from other sulphides of 
similar color. 
395. How is cadmium separated from zinc? 
396. How does bismuth occur in nature ? 
397. What is the quantivalence of bismuth? 
398. Write down equations descriptive of the actions of nitric acid 
on bismuth, and water on nitrate of bismuth. 
399. How may pure salts be prepared from bismuth containing 
arsenicum ? 
400. Give a diagram of the process for the so-called Carbonate of 
Bismuth. 
401. Write formulae showing the accordance in composition of the 
official Subnitrate and Carbonate with the other salts of Bismuth, and 
with ordinary Nitrates and Carbonates. 
402. How is Bismuthi et Ammonii Citras prepared ? 
403. What are the tests for Bismuth? 
Practical Analysis. 
Bismuth is the last of the metals whose synthetical or analytical 
relations are of general interest. The position of the rarer among 
the common metals, and the influence which either has on the other 
during the manipulations of analysis, will now be considered. These 
objects will be best accomplished, and a more intimate acquaintance 
with all the metals be obtained, by analyzing, or studying the meth- 
ods of analyzing, solutions containing one or more metallic salts. 
Of the following Tables, the first (1) includes directions for the 
analysis of an aqueous or only slightly acid solution, containing but 
one salt of any of the metals hitherto considered. Here the color PRACTICAL ANALYSI 
253 
of the precipitate or precipitates afforded by a metal under given 
circumstances must largely be relied on in attempting the detection 
of the various elements. 
1 he folded Table (2) is intended as a chart for the analysis of solu- 
tions containing salts of more than one of the common and rarer 
metals. It is simply a compilation from the foregoing reactions—an 
extension of the scheme for the analysis of salts of the ordinary met- 
als. Hence it often may be altered or varied in arragement to suit 
the requirements of the" analyst. 
That on p. 255 is a mere outline of the other two Tables. It gives 
the position of the metals in relation to each other, and will much aid 
the memory in recollecting that relation. 
The analysis of solutions containing only one metal will, as already 
stated, serve to impress, the memory with the characteristic tests for 
the various metals and other radicals, and familiarize the mind with 
chemical principles. Medical students seldom have time to go further 
than this. More thorough analytical and general chemical knowledge 
is only acquired by working on such mixtures of bodies as are met 
with in actual practice, beginning with solutions which may contain 
any or all of the members of a group (see previous pages), then 
examining solutions containing more than one group, and finally 
analyzing liquids in which are dissolved several salts of any of the 
common or rarer metals. 
The Author cannot too strongly recommend students thoroughly 
to master the art of analysis, not only on account of its direct value, 
but because its practice enables the learner rapidly and soundly to 
acquire a good knowledge of chemistry, and greatly to improve his 
general mental faculties. RARER METALLIC RADICALS. 
1. TABLE OF SHORT DIRECTIONS FOR THE ANALYSIS OF AN AQUEOUS OR ONLY SLIGHTLY ACID SOLUTION OF 
ORDINARY SALTS OF ONE OF THE ELEMENTS HITHERTO CONSIDERED THE COMMON AND RARER METALS. 
Add hydrochloric acid. 
Precipitate 
Hg(ous) Pb Ag. 
Collect, wash, and add 
AmllO. 
Hg ppt., blackened. 
Pb ppt., still white. 
Ag ppt., dissolved. 
Sb and Bi may also 
be precipitated by 
HC1, but are dissolv- 
ed on adding more 
HC1. 
If IIC1 gave no precipitate the metal is still in the liquid; pass H2S through the solution. 
Precipitate 
Cd Cu Hg(ic) Pb Bi As 
Sb Sn Au Pt. 
Collect wash, add AmHS. 
Insoluble 1 Soluble. 
Cd, yellow. As(ous & ic) ) 
Hg(ic) ] i Sl'<ic) Jl. 
Pb f ~ Sb, orange. 
Bi j j Sn(ous) ) 
1 Au V § 
i Pt j 3 
Apply special tests for each 
to the original solution. For 
these, see the previous pages. 
If II2S gave no precipitate add AmCl, AmHO, and AmHS. 
Precipitate 
Zn Mn Co Ni A1 
Fe Cr. 
A1 }white- 
Cr, green. 
Mn, skin-tint. 
Ni) 
Co V black. 
Fe ) 
Test specially 
for each in orig- 
inal solution. See 
previous pages. 
If AmHS gave no precipitate add Am2C03. 
Precipitate 
Ba Sr Ca. 
Collect, wash, dis- 
solve in HC2H302, 
add K2Cr04. 
If Am2C03 gave no pre- 
cipitate add Am2lIAs04. 
Ppt. 
Mg. 
If no precip- 
itate, test orig- 
inal solution in 
flame on loop 
of Pt wire. 
L, crimson. 
Na, yellow. 
K, violet. 
If neither, test 
orig. sol. for Am. 
Ppt. 
Ba. 
Sol. 
Sr Ca 
Add dil. 
II2S04. 
Ppt. Sol. 
Sr.—Ca. [To face page 254. 
2. TABLE OF SHORT DIRECTIONS FOR APPLYING SOME OF THE FOREGOING ANALYTICAL REACTIONS TO THE ANALYSIS OF AN AQUEOUS OR ONLY SLIGHTLY ACID SOLUTION OF ORDINARY 
SALTS OF ANY OF THE COMMON OK RARER METALS. 
Add hydrochloric acid. 
r ' | 
Precipitate 
Hg(ous) Pb Ag. 
Wash, boil with water, filter. 
Cd Cu 
Filtrate 
Hg(ic) Pb Bi As(ous)(ic) Sb Sn(ous)(ic) Zn Mn C’o Ni A1 Fe(ous)(ic) Cr Ba Ca Sr Mg L 
Pass 1I2S through the liquid, filter. 
K Na Am. 
Precipitate 1 Filtrate ! 
Hg(ousl Ag. Pb. 
Wash, add AniHO. Add H2S04. 
i White”ppt. 
Precipitate 
Cd Cu Hg(ic) Pb Bi As Sb Sn. 
Collect, wash, digest in AmHS, filter. 
Filtrate 
Zn Mn Co Ni A1 Fe Cr Ba Ca Sr Mg L IC Na Am. 
Add AmCl, AmHO, AmHS, warm gently and filter. 
Ppt. Filtrate 
Hg Ag 
(ous). Add HN03. 
Black White ppt. 
j PPt. 1 
Precipitate 
Cd Cu Hg(ie) Pb Bi. 
Wash, boil in HNO;j, filter. 
Filtrate 
As Sb Sn. 
Add dilute HC1, filter, drain well, add strong 
HC1, boil, dilute slightly, filter. 
Precipitate 
Zn Mn Co Ni A1 Fe Cr. 
Collect, wash, dissolve in HC1 with a few drops of IIN03, 
boil, add AmHO, stir, filter. 
Filtrate 
Ba Ca Sr Mg L K Na Am. 
Add Am2C03, warm, filter. 
See also p. 256. 
Ppt. 
Hg 
(1C). 
Black. 
Confirm 
by Cu 
Filtrate 
Cd Cu Pb Bi. 
Add AmHO, filter. 
Insol. 
As. 
Yellow. 
Confirm 
by Fleit- 
mann’s 
Filtrate 
Sn Sb. 
Pour into H-apparatus. 
Precipitate * 
Fe Al Cr. 
Wash, dry, fuse on foil with 
Na2C03 aud KN03, boil in 
water and filter. 
Filtrate 
Zn Mn Co Ni. 
Acidify with H(’2H302, pass II2S, 
filter. 
Precipitate 
Ba Sr Ca. 
Collect, wash, dissolve in 
HC2H302, add excess of 
K2C”r04, filter. 
Filtrate 
Mg L K Na Am. 
Add Am2HAs04, stir, filter. 
test in 
original 
solu- 
tion. 
Precipitate 
Pb Bi. 
Wash, add a tew 
drops HN03, 
dilute, filter. 
Filtrate 
Cd Cu. 
Add KCy and 
h2s. 
test. 
Sn Sb 
remains on Zn. escapes as SbII3. 
Dissolve in HC1 Test as usual, 
and apply tests. 
Residue 
Fe203, 
brown. 
Test 
original 
Filtrate. 
If yellow, Cr pre- 
sent. Divide in 
two parts. 
Sol. 
Mn. 
Add 
AmHO 
and 
Precipitate 
Zn Co Ni. 
Boil with HC1 and a little 
HN03 ; add KHO, filter. 
Ppt. 
Ba. 
Yellow. 
Filtrate 
Sr Ca. 
Add dilute II2S04, 
let stand, filter. 
Ppt. 
Mg. 
Filtrate 
L K Na Am. 
Evaporate to small 
bulk. Add AmHO. 
See also pp. 256-257. 
solution 
AmHS. 
Ppt. Filt. 
Bi. Pb. 
Dilute, 
add 
H2S04, 
set aside. 
White 
ppt. 
See also pp. 2 
Ppt. 
Cd. 
Yel- 
low. 
>6-257. 
Filt. 
Cu. 
Acidify 
with 
HC2H302. 
Brown ” 
ppt. 
Au and Pt are specially sought when necessary. 
for 
ferrous 
or ferric 
state. 
Sol. 
Al. 
Add 
AmCl, 
warm 
and 
filter. 
White 
ppt. 
Sol. 
Cr. 
Add 
hc2h3o2 
and excess 
of AgN03; 
red ppt' 
Or boil 
with H2S04 
and spirit. 
Green 
solution. 
Pink, 
turning 
brown. 
Search 
also for 
Mn in 
the 
Fe Al Cr 
ppt. 
Filt. 
Zn 
AmHS. 
White 
ppt. 
Precipitate 
Co Ni. 
Dissolve in HC1, 
and proceed as 
directed on pp. 
233. 
Sec 
Ppt. 
Sr. 
also p 
Filt. 
Ca. 
Add 
Am2C204. 
White 
ppt. 
. 257. 
Ppt. 
L. 
Filtrate 
K Na Am. 
Evaporate, 
ignite, dissolve. 
K by PtCl4, 
Na by flame. 
Am in original 
solution. 
See also pp. 256-257. 
* Test this also for Mn, by 
Crum’s process, p. 230. ANALYTICAL TABLES. 
255 
3. OUTLINE OF THE ANNEXED ANALYTICAL TABLES. 
IIC1 
H2S 
AmllS. 
Am2C03 
Am2IIAs04 
Hg 
Cd 
Zn 1 
d 
Ba 
Mg 
K 
(as mercurous 
salt) 
Cu 
< 
Pb 
Mn* 
.2 
Sr 
Na 
(partially) 
Ilg 
< 
3 
a 
pi 
(as mer- 
« 
Co 
Ca 
Am 
curie 
salt) 
3 
p 
© 
z> 
"r" 
Ag 
Pb 
(entirely) 
Bi 
Ni 
A1 
s 
o 
As 
2 
(as arse- 
< 
nious or 
Fe 
— 
L 
arsenic 
salt) 
rri 
Sb 
5 
ts 
< 
Cr 
V 
Sn 
[•- 
* 
(as stan- 
nous or 
p 
stannic 
salt) 
zfl 
• See page 
229. 
Au 
Pt 
The laboratory student should practise the examination of aque- 
ous solutions of salts of the above metals until able to analyze with 
facility and acuracy. 
General and Special Memoranda relating to the 
preceding Analytical Tables. 
General Memoranda. 
These charts are constructed for the analysis of salts more or less 
soluble in water. The student has still to learn how substances 
insoluble in water are to be brought into a state of solution; but, 
once dissolved, their analysis is effected by the same scheme as that 
just given. The Tables, especially the second (No. 2), may there- 
fore be regarded as fairly representing the method by which metallic 256 
THE METALLIC RADICALS. 
constituents of chemical substances are separated from each other 
and recognized. The methods of isolation of the complementary 
constituent of the salt (the reactions of non-metals and acidulous 
radicals) will form the next object of practical study. 
The general memoranda given in connection with the first Table 
(p. 219) are equally applicable to the extended second Table, and 
should again be carefully read through. 
The hydrochloric-acid precipitate may at first include some anti- 
mony and bismuth as oxychlorides, readily dissolved, however, by 
excess of acid. If either of these elements be present, the wash- 
ings of the precipitate will probably be milky ; in that case add a 
few drops of hydrochloric acid, which will clear the liquid and make 
way for the application of the test for lead. 
The sulphuretted-hydrogen precipitate may be white, in which 
case it is nothing but sulphur ; for, as already indicated, ferric salts 
are reduced to ferrous, and chromates to the lower salts of chromium 
by sulphuretted hydrogen, sulphur being deposited:— 
Special Memoranda. 
2Fe2Cl6 + 2II2S = 4FeCl2 + 4IIC1 -f S2; 
4II2Cr04 + 6H2S + 12IIC1 = 2Cr2Cl6 + 16II20 + 3S2. 
But the precipitate may also be colored, or even white when only 
lead or mercury is present, through an insufficiency of sulphuretted 
hydrogen having produced a peculiar oxysulphide or hydrato-sul- 
phide. The gas should be passed through the liquid until, even 
after well shaking, it smells strongly of sulphuretted hydrogen. 
The portion of the sulphuretted-hydrogen precipitate dissolved 
by sulphydrate of ammonium may include a trace of copper, sul- 
phide of copper being not altogether insoluble in sulphydrate of 
ammonium. On adding hydrochloric acid to the sulphydrate-of- 
ammonium solution, a white precipitate of sulphur only may be 
produced, the sulphydrate of ammonium nearly always containing 
free sulphur. Strong hydrochloric acid does not readily dissolve 
small quantities of sulphide of antimony out of much sulphide of 
arsenicum ; and, on the other hand, the strong hydrochloric acid 
takes into solution a small quantity of sulphide of arsenicum if 
much sulphide of antimony is present. The precipitate or the 
original solution should therefore be examined by the other (hydro- 
gen) tests for these elements if doubt exists concerning the presence 
or absence of either. Tin remains in the hydrogen-bottle in the 
metallic state, deposited as a black powder on the zinc used in the 
experiment. The contents of the bottle are turned out into a dish, 
ebullition continued until evolution of hydrogen ceases, and the 
zinc is taken up by the excess of sulphuric acid employed ; any tin 
is then filtered out, washed, dissolved in a few drops of hydro- 
chloric acid, and the liquid tested for tin by the usual reagents. 
Tin may be detected in the mixed sulphides of tin, arsenicum, 
and antimony by the blowpipe reaction (vide Index). 
The portion of the sulphuretted-hydrogen precipitate not dis- 
solved by the sulphydrate of ammonium may leave a yellow semi- ANALYTICAL MEMORANDA. 
257 
fused globule of sulphur on boiling with nitric acid. This globule 
may be black, not only from presence of mercuric sulphide, but also 
from inclosed particles of other sulphides protected by the sulphur 
from the action of the acid. It may also contain sulphate of lead, 
produced by the action of nitric acid on sulphide of lead. In cases 
of doubt the mass must be removed from the liquid, boiled with 
nitric acid till dissolved, the solution evaporated to remove excess of 
acid, and the residue examined; but usually it may bo disregarded. 
before testing for bismuth, any considerable excess of acid 
should be removed by evaporation, and the residual liquid should 
be freely diluted. If no precipitate (oxynitrate of bismuth) appear, 
chloride-of-ammonium solution may be added, oxychloride of bis- 
muth more readily forming than even oxynitrate. Or any nitric 
acid or sulphuric acid having been neutralized by ammonia, hydro- 
chloric acid is added, and then iodide of potassium ; a rich orange 
color results if bismuth be present. In testing for lead by sul- 
phuric acid the liquid should be diluted and set aside for some time. 
Mercury may also be isolated by digesting the sulphuretted-hydro- 
gen precipitate in sulphydrate of sodium instead of sulphydrate of 
ammonium. The sulphides of arsenicum, antimony, tin, and mer- 
cury are thus dissolved out. The mixture is then filtered, excess of 
hydrochloric acid added to it, and the precipitated sulphides collected 
on a filter, washed, and digested in sulphydrate of ammonium; sul- 
phide of mercury remains insoluble, while the sulphides of arseni- 
cum, antimony, and tin are dissolved. By this method copper also 
appears in its right place only, sulphide of copper being quite 
insoluble in sulphydrate of sodium. The other metals are then 
separated in the usual way. 
The sulphydrate-of-ammonium precipitate may, if the original 
solution was acid, contain Phosphates, Oxalates, Silicates, and Bo- 
rates of Barium, Calcium, and Magnesium. These will subsequently 
come out with the iron, and, being white, give the iron precipitate a 
light-colored appearance ; tbeir examination must be conducted sep- 
arately, by a method described subsequently in connection with the 
treatment of substances insoluble in water. The precipitates con- 
taining aluminium, iron, and chromium hydrates often contain some 
manganese. This manganese may be detected by washing the hy- 
drates to remove all traces of chlorides, boiling with nitric acid, 
adding either puce-colored oxide of lead or red lead, and setting the 
vessel aside. If manganese be present a red or purple liquid is pro- 
duced. Sulphide of nickel is not easily removed by filtration {cicle 
p. 232) until most of the excess of sulphydrate of ammonium has 
been dissipated by prolonged ebullition. 
The carbonate-of-ammonium precipitate may not contain the 
whole of the barium, strontium, and calcium in the mixture, unless 
free ammonia be present; for the carbonates of those metals are 
soluble in water charged with carbonic acid. If, therefore, the liquid 
is not distinctly amruoniacal, solution of ammonia should be added. 
Neither carbonate nor hydrate of ammonium wholly precipitates 
magnesian salts ; and, as a partial precipitation is undesirable, a sol- 
vent, in the form of an alkaline salt (chloride of ammonium), if not 258 
THE METALLIC RADICALS. 
already in the liquid, should be added. In the chart opposite p. 
254 strontium is ordered to be separated from calcium by adding to 
the acetic solution diluted sulphuric acid. The latter, unless ex- 
tremely dilute, may precipitate calcium. Any such loss of calcium 
is in itself of little consequence, because enough sulphate of calcium 
remains in the liltrate to afford a calcium reaction when ammonia 
and oxalate of ammonium are subsequently added. But the cal- 
cium precipitated by the sulphuric acid may be wrongly set down as 
strontium. Therefore test a little of the acetic solution for strontium 
by an aqueous solution of sulphate of calcium, when, if no precipi- 
tate falls after setting aside for several minutes, strontium may be 
regarded as absent. If a precipitate occurs strontium is present; 
the rest of the acetic solution is then tested for calcium as directed 
in the chart, the final testing by oxalate of ammonium being, of 
course, preceded by the addition of ammonia. 
Lithium.—The search for lithium may usually be omitted. Should 
a precipitate, supposed to be due to lithium, be obtained, it must be 
tested in a flame ( scarlet tint), as a little magnesium not unfre- 
quently shows itself under similar circumstances. 
Spectral Analysis.—If present only in minute proportions, the 
lithium may also remain with the alkalies ; it can then only be de- 
tected by physical analysis (by a prism) of the light emitted from a 
tinged flame—by, in short, an instrument termed a spectroscope. 
Such a method of examination is called spectral analysis, a subject 
of much interest and of no great difficulty, but scarcely within the 
range of Pharmaceutical Chemistry; it will be briefly described in 
connection with the methods of analyzing solid substances. 
404. Describe a general method of analysis by which the metal of 
a single salt in a solution could be quickly detected. 
405. Give illustrations of black, white, light pink, yellow, and 
orange sulphides. 
406. Mention the group-tests generally employed in analysis. 
407. Under what circumstances may a hydrochloric precipitate 
contain antimony or bismuth? 
408. If a sulphuretted-hydrogen precipitate is white, what sub- 
stances are indicated? 
409. Give processes for the qualitative analysis of liquids contain- 
ing the following substances :— 
QUESTIONS AND EXERCISES. 
a. Arsenicum and Cadmium. 
b. Bismuth and Antimony. 
c. Ferrous and Ferric salts. 
cl. Aluminium, Iron, and Chromium. 
e. Arsenicum, Antimony, and Tin. 
f. Lead and Strontium. 
y. Iron, Sodium, and Arsenicum. 
h. Mercury, Manganese, and Magnesium. 
i. Zinc, Manganese, Nickel, and Cobalt. 
j. Barium, Strontium, and Calcium. THE ACIDULOUS RADICALS. 
259 
THE ACIDULOUS RADICALS. 
Introduction.—The twenty-seven radicals which have up to this 
point mainly occupied attention are (admitting ammonium, NII4) 
metals; and they have been almost exclusively studied not in the 
free state, but in the condition in which they exist in salts. More- 
over, these metals have been treated as if they formed the more im- 
portant constituent, the stronger half, the foundation or base of salts. 
Attention has been continuously directed to the metallic or basylous 
side of salts. And indeed there is still one more basylous radical 
which must be mentioned, though it is usually supposed to play only 
a subordinate part in medicine—Hydrogen. Unlike the salts of 
most metals, those of hydrogen (the so-called acids) are never, in 
medicine or the arts generally, professedly used for the sake of their 
hydrogen, but always for the other half of the salt, the acidulous 
side. And it is not for their basylous radical that these hydrogen 
salts are now commended to notice,* but in order to study, under the 
most favorable circumstances, those acidulous groupings which have 
continually presented themselves in operations on salts, but which 
were for the time of secondary importance. These acidulous radi- 
cals may now be treated as the primary object of attention; and 
there is no better wray of doing so than in operating on their com- 
pounds with hydrogen, the relatively inferior medicinal importance 
of which element, as compared w'ith potassium, iron, and other 
basylous radicals, will serve to give the desired prominence to the 
acidulous radicals in question. 
Common Acids.—These salts of hydrogen (hydrogen easily dis- 
placeable, or in certain cases, in part, by ordinary metals) are ohe 
ordinary sharp, sour bodies termed acids (from the Latin root acies, 
an edge). The following Table includes the formulm and usual 
names of the most important; others will be noticed subsequently. 
A few of those mentioned are unstable or somewhat rare; in such 
cases a common metallic salt containing the acidulous radical may 
be used for reactions. 
* It must not be forgotten that the commonest salt of anv radical 
whatsoever is a salt of hydrogen, the oxide of hydrogen (H20), or 
hydrate of hydrogen (HIIO), water. In the reactions already per- 
formed the value of this compound has been constantly recognized, 
both for its hydrogen and for its oxygen, but most of all as the vehicle 
or medium by which nearly all other atoms are enabled to come into 
that contact with each other without which their existence would be 
almost useless; for some atoms are like some animals—out of water 
they are as inactive as fishes. It is true that both fishes and salts have 
usually to be removed from water to be utilized by man; but before 
they can be assimilated, either as food or as medicine, they must again 
seek the agency of water in becoming dissolved. THE ACIDULOUS RADICALS. 
IIC1 hydrochloric acid. 
llBr hydrobromic acid. 
Ill hydriodic acid. 
IICN (HCy) hydrocyanic acid. 
HN03 nitric acid. 
IICIO., chloric acid. 
HC2H302 acetic acid.* 
II.2S hydrosulphuric acid.f 
H2S03 sulphurous acid. 
H2S04 sulphuric acid. 
H2C03? carbonic acid. 
II2C204 oxalic acid. 
H2C4H406 tartaric acid. 
1I3C6II507 citric acid. 
H3P04 phosj)horic acid. 
H»BO, boracic acid. 
The old names are here retained for these acids, but, in studying 
their chemistry and chemical relations to other salts, they are use- 
fully spoken of by such more purely chemical names as (for hydro- 
chloric acid) chloride of hydrogen, (for nitric acid) nitrate of hydro- 
gen, and so on—sulphate of hydrogen, tartrate of hydrogen, phos- 
phate of hydrogen. 
A prominent point of difference will at once be noticed between 
the basylous radicals met with up to the present time and the acidu- 
lous groupings included in the above tabular list. The former are 
nearly all elements, ammonium only being a compound; the latter 
are mostly compounds, chlorine, bromine, iodine, and sulphur being 
the only elements. This difference will not, however, be so appar- 
ent when the chemistry of alcohols, ethers, and such bodies has 
been mastered, for they are all salts of compound basylous radicals. 
Rarer Acids.—The above acids contain the only acidulous group- 
ings that commonly present themselves in analysis or in pharma- 
ceutical operations. There are, however, several other acids (such 
as hypochlorous, nitrous, hypophosphorous, valerianic, benzoic, 
gallic, tannic, uric, hyposulphurous, hydroferrocyanic, hydroferrid- 
cyanic, lactic, etc.) w ith which it is desirable to be more or less fa- 
miliar; reactions concerning these wfill therefore be described. Ar- 
senious, arsenic, stannic, manganic, and chromic acids have already 
* The hydrogen on the acidulous side must not be confounded with 
the basylous hydrogen in all these, hydrogen salts or acids; the two 
perform entirely different functions. Hydrogen in the acidulous por- 
tion is like the hydrogen in the basylous radical ammonium: it has 
combined with other atoms to form a group which plays more or less 
the part of an elementary radical, and to which a single symbol is not 
unfrequently applied (Am; Cy, A, O, T, C, etc.). Cobalt, chromium, 
iron, platinum, etc., resemble hydrogen in this respect in often uniting 
with other atoms to form definite acidulous radicals, in which the usual 
basylous character of the metals has for the time disappeared. In hy- 
drides (p. 121) hydrogen itself is an acidulous radical. 
f Synonyms: sulphydric acid and sulphuretted hydrogen. SALTS OF ACIDULOUS RADICALS. 
261 
been treated of in connection with the metals they contain ; in prac- 
tical analysis they always become sufficiently altered to come out 
among the metals. 
Qnantivalence.—A glance at the foregoing Table is sufficient to 
show the quantivalence of the acidulous radicals. The first seven 
are clearly univalent, then follow six bivalent, leaving three triv- 
alent. 
These all combine with equivalent amounts of basylous radicals to 
form various salts ; hence they may be termed monobasylous, dibasy- 
lous, and tribasylous radicals. The acids themselves were formerly 
spoken of as monobasic, dibasic, and tribasic respectively, or mono- 
basic and polybasic, in reference to the amount of base (hydrates or 
oxides) they could decompose; but the terms are no longer definite, 
and hence but little used in mineral chemistry. 
Antidotes.—The antidotes in cases of poisoning by the strong 
acids will naturally be non-corrosive alkaline substances, as soap 
and water, magnesia, common washing u soda,” or other carbonates. 
Vinegar, lemon-juice, and weak or non-corrosive acids would be the 
appropriate antidotes to caustic alkalies. 
Analysis.—The practical study of the acidulous side of salts will 
occupy far less time than the basylous. Salts will then be briefly 
examined as a whole. 
One Word of Caution.—It is only for convenience in the division 
of chemistry for systematic study that salts may be considered to 
contain basylous and acidulous radicals, or separate sides, so to speak; 
for we possess no absolute knowledge of the internal arrangement of 
the atoms (admitting that there are such things) in the molecule of 
a salt. We only know that certain groups of atoms may be trans- 
ferred from compound to compound in mass (that is, without apparent 
decomposition) ; hence the assumption that these groups are radicals. 
A salt is probably, hovrever, a whole, having no such sides as those 
mentioned. 
QUESTIONS AND EXERCISES. 
410. Mention the basylous radical of acids. 
411. Give illustrations of univalent, bivalent, and trivalent acidu- 
lous radicals, or monobasylous, dibasylous, and tribasylous radicals. 
412. What is the difference between an elementary and a com- 
pound acidulous radical ? 
413. Name the grounds on which salts may be assumed to contain 
basylous and acidulous radicals. 
HYDROCHLORIC ACID AND OTHER CHLORIDES. 
Formula of Hydrochloric Acid IIC1. Molecular weight* 36.4. 
The acidulous radical of hydrochloric acid and of other chlorides 
is the element chlorine (Cl). It occurs in nature chiefly as chloride 
* The weight of a molecule is the sum of the weights of its atoms. 262 
SALTS OF ACIDULOUS RADICALS. 
of sodium (NaCl), either solid, under the name of rock-salt, mines 
of which are not unfrequently met with, or in solution in the water 
of all seas. Common table-salt is more or less pure chloride of sodium 
in minute crystals. Chlorine, like hydrogen, is univalent (Cl/); its 
atomic weight is 35.4. Its molecule is symbolized thus, Cl2, chloride 
of chlorine. 
Hydrochloric Acid. 
Reactions. 
First Synthetical Reaction.—To a few fragments of chloride 
of sodium in a test-tube or small flask add about an equal 
weight of sulphuric acid ; colorless and invisible gaseous hydro- 
chloric acid is evolved, a sulphate of sodium remaining. Adapt 
to the mouth of the vessel by a perforated cork a piece of glass 
tubing bent to a right angle, heat the mixture, and convey the 
gas into a small bottle containing a little water; solution of 
hydrochloric acid results. 
NaCl + H2S04 = II Cl + NaHSO, 
Chloride of 
sodium. 
Sulphuric 
acid. 
Hydrochloric 
acid. 
Acid sulphate 
of sodium. 
Hydrochloric Acid.—The product of this operation is the nearly 
colorless and very sour liquor commonly called hydrochloric acid. 
When of certain given strengths (estimated by volumetric analysis) 
it forms Acidum Hydrochloricum, U. S. P. (Acidum Muriaticum), 
and Acidum Hydrochloricum Dilutum, U. S. P. The former has a 
specific gravity of 1.16 and contains 31.9 per cent, of real acid. 
The latter, specific gravity 1.049, with 10 per cent, of the real acid, 
is made by diluting 6 fluid parts of the strong acid with 13 of water. 
The above process is that of the manufacturer, larger vessels being 
employed, and the gas being freed from any trace of sulphuric acid 
by washing. Other chlorides yield hydrochloric acid when heated 
with sulphuric acid; but chloride of sodium is always used, because 
cheap and common. 
Common yellow hydrochloric acid is a by-product in the manu- 
facture of carbonate of sodium from common salt, a process in which 
the chloride of sodium is first converted into sulphate, hydrochloric 
acid being liberated. This impure acid is liable to contain iron, 
arsenic, fixed salts, sulphuric acid, sulphurous acid, nitrous com- 
pounds, and chlorine. 
The process for the preparation of hydrochloric arid is as follows : 
it may be carried out by the student with about one-twelfth of the 
quantities mentioned:— 
“ Take of chloride of sodium, dried, 48 ounces, sulphuric acid 44 
fluidounces, water 36 fluidounces, distilled water 50 fluidounces; 
pour the sulphuric acid slowly into 32 ounces of the water, and, 
when the mixture has cooled, add it to the chloride of sodium pre- 
viously introduced into a flask having the capacity of at least one 
gallon: Connect the flask by corks and a bent glass tube with a 
three-necked wash-bottle, furnished with a safety-tube, and contain- CHLORIDES. 
ing the remaining 4 ounces of the water [or let the flask-tube pass 
loosely through a wider tube fixed in the cork of the wash-bottle, as 
shown in Fig. 37] ; then, applying heat to the flask, conduct the 
Fig. 37. 
Preparation of Hydrochloric Acid. 
disengaged gas through the wash-bottle into a second bottle contain- 
ing the distilled water, by means of a bent tube dipping about half 
an inch below the surface, and let the process be continued until the 
product measures 36 ounces, or the liquid has acquired a specific 
gravity of 1.16. The bottle containing the distilled water must be 
kept cool during the whole operation.” 
The modification of wash-bottle shown in the figure allows of the 
easy insertion or removal of a delivery-tube. The wider tube there 
shown, or an ordinary tube-funnel, also acts as a safety-tube by ad- 
mitting air the moment there is any tendency in the water in the 
receiver to be forced back on account of a too rapid absorption of 
the gas. The time of the student will be saved if hydrochloric acid 
already in stock be placed in the wash-bottle instead of water. 
Invisible gaseous hydrochloric acid forms visible grayish-white 
fumes on coming into contact with air. This is due to combination 
with the moisture of the air. The intense greediness of hydro- 
chloric gas and water for each other is strikingly demonstrated on 
opening a test-tube full of the gas under water; the latter rushes 
into and instantly fills the tube. If the water is tinged with blue 
litmus, the acid character of the gas is prettily shown at the same 
time. The test-tube, which should be perfectly dry, may be filled 
from the delivery-tube direct; for the gas is somewhat heavier than, 
and therefore readily displaces, air. The mouth may be closed by 
the thumb of the operator. At low temperatures hydrochloric acid 
and water form a crystalline compound, IIC1,2II20. 
Note.—The process includes the use of as much sulphuric acid as 
is theoretically necessary for the production of acid sulphate of 
sodium (NaIIS04), which remains in the generating vessel. A hot 
solution of this residue carefully neutralized by carbonate of sodium, 
filtered and set aside, yields normal sulphate (Sodii Sulphas, U. S. 264 
SALTS OF ACIDULOUS RADICALS. 
P.), “Glauber’s Salt,” in the form of transparent oblique efflor- 
escent prisms (Na2S04,l()II20). 
2NaHS04 + Na2C03 = 2Na2S04 + II20 + C02 
Acid sulphate 
of sodium. 
Carbonate of 
sodium. 
Sulphate of 
sodium. 
Water. 
Carbonic 
acid gas. 
Chlorine. 
Second Synthetical Reaction.-—To some drops of hydrochloric 
acid (that is, the common aqueous solution of the gas) add a 
few grains of black oxide of manganese, and warm the mixture; 
chlorine, the acidulous radical of all chlorides, is evolved, and 
may be recognized by its peculiar odor or irritating effect on 
the nose and air-passages. 
4HC1 + Mn02 = Cl2 + 2H20 + MnCl2. 
Chlorine-water.—This is the process of the Pharmacopoeia for the 
production of chlorine-water (Aqua Chlori, U. S. P.), the gas being 
first washed and then passed into water. Chlorine slowly decom- 
poses water, with production of hydrochloric acid and oxygen gas; 
it is best preserved in a green-glass well-stoppered bottle in a cool 
and dark place. At common temperatures (60° F.), if fresh and 
thoroughly saturated, chlorine-water contains more than twice (2.3) 
its bulk of chlorine, or less than 1 per cent, (about 0.75) by weight. 
Chlorine passed into cold water yields crystals of hydrous chlorine 
(Cl 5H20), and these when heated under pressure give an upper layer 
of chlorine-water and a lower layer of liquid chlorine. 
Note.—To obtain the chlorine from other chlorides, sulphuric acid 
as well as black oxide of manganese must be added. Hydrochloric 
acid is first formed. The action described in the foregoing equation 
then goes on, except that half instead of the whole of the oxygen 
of the black oxide is available for the removal of the hydrogen from 
the chlorine of the hydrochloric acid, the other half being taken up 
by the hydrogen of the sulphuric acid. Thus, supposing common 
salt to be the chloride used, the following equations may represent 
the supposed steps of the process:— 
2NaCl + H2S04 = Na2S04 + 2IIC1, 
Mn02 + II2S04 = MnS04 + II20 -f- 0; 
then the 2HCf +0 = H20 + Cl2 
or the whole may be included in one equation:— 
2NaCl + Mn02 + 2II2S04 = Na2S04 + MnS04 +2H20 + Cl2. 
This reaction may have occasional analytical interest, a very 
small quantity of combined chlorine being recognized by its means. 
But the following test is nearly always applicable for the detection 
of this element, and leaves nothing to be desired in point of delicacy. 
Analytical Reactions ( Test). 
To a drop of hydrochloric acid, or to a dilute solution of any BROMIDES. 
265 
other chloride, add solution of nitrate of silver; a white curdy 
precipitate falls. Pour oft’ most of the supernatant liquid, add 
nitric acid and boil; the precipitate does not dissolve. Pour 
off the acid, and add dilute ammonia; the precipitate quickly 
dissolves. Neutralize the solution by an acid; chloride of silver 
is once more precipitated. 
The formation of this white precipitate, its appearance, insolu- 
bility in boiling nitric acid, solubility in ammonia and in solution 
of its carbonate and reprecipitation by an acid, form abundant evi- 
dence of the presence of chlorine. Its occurrence as a chloride of 
a metal is determined by testing for the metal with the appropriate 
reagent; its occurrence as hydrochloric acid is considered to be 
indicated by the odor, if strong, and the sour taste, if weak, of the 
liquid, and the action of the liquid on blue litmus-paper, which, like 
other acids, it reddens. If hydrochloric acid be present in excessive 
quantity, it will, in addition to the above reactions, give rise to 
strong effervescence on the addition of a carbonate, a chloride being 
formed. The chlorine in insoluble chlorides, such as calomel, “ white 
precipitate,” etc., may be detected by boiling with caustic potash, 
filtering, acidulating the filtrate by nitric acid, and then adding the 
nitrate of silver. 
Antidotes.—In cases of poisoning by strong hydrochloric acid, 
solution of carbonate of sodium (common washing soda) or a mix- 
ture of magnesia and water may be administered as an antidote. 
QUESTIONS AND EXERCISES. 
414. A specimen of official Hydrochloric Acid contains 31.8 per 
cent, by weight of gas, and its specific gravity is J .16 5 work out a 
sum showing what volume of it will be required, theoretically, to 
mix with black oxide of manganese for the production of one gallon 
of chlorine-water, one fluidounce of which contains 2.66 grains of 
chlorine. Ans. 5£ fluidounces, nearly (5.4). 
415. Why does hydrochloric acid gas give visible fumes on com- 
ing into contact with air ? 
416. How much chloride of sodium will be required to furnish 
one pound of chlorine? 
417. Give the analytical reactions of chlorides. 
418. What antidotes may be administered in cases of poisoning 
by hydrochloric acid? 
HYDROBROMIC ACID AND OTHER BROMIDES. 
Formula of Hydrobromic Acid HBr. Molecular weight 80.8. 
Bromine: Source, Preparation, and Properties.—The acidulous 
radical of hydrobromic acid and other bromides is the element bro- 
mine, Br (Bromum, U. S. P.). It occurs in nature chiefly as bro- SALTS OF ACIDULOUS RADICAL. 
mide of magnesium (MgBr2) in sea-water and certain saline springs, 
and is commonly prepared from the bittern, or residual liquors of 
salt-works. It may be liberated from its compounds by the process 
for chlorine from chlorides—that is, by heating with black oxide of 
manganese and sulphuric acid (see page 254). It is a dark-red vola- 
tile iiquid, emitting an odor more irritating, if possible, than chlo- 
rine—of specific gravity 2.990, boiling-point 145.4° F. 
Test of purity, U. S. P.—If 3 gm. of Bromine be mixed with 30 
c.c. of water and enough water of ammonia to render the solution 
colorless, the liquid then digested with carbonate of barium, filtered, 
evaporated to dryness, and the residue gently ignited, the latter 
[chiefly bromide of barium] should be soluble in absolute alcohol 
without leaving more than 0.26 gm. of residue [chloride of barium] 
(abs. of more than 3 per cent, of chlorine). If an aqueous solution 
of Bromine be poured upon reduced iron and shaken with the latter 
until it has become nearly colorless, then filtered, mixed with gelat- 
inized starch, and a few drops of Bromine solution be now carefully 
poured on top, not more than a very faint blue zone should appear 
at the line of contact of the two liquids (limit of iodine). 
Quantivalence.—The atom of bromine, like that of chlorine, is 
univalent (Brr). The atomic weight of bromine is 79.8. Free bro- 
mine has the molecular formula Br2, bromide of bromine. 
Fig. 38. 
Preparation of Hydrobromic Acid. 
Hydrobromic Acid.—The bromide of hydrogen, hydrobromic acid, 
may be made by decomposing bromide of phosphorus by water— 
PBr5 + 4H20 = 5HBr H8P04. A small quantity may be pre- 
pared by placing seven or eight drops of bromine at the bottom of 
a test-tube, putting in fragments of glass to the height of about an 
inch or two, then ten or eleven grains of phosphorus, then another 
inch of glass, and finally a couple of inches of glass fragments 
slightly wetted with water, a delivery-tube being fitted on by a 
cork. The phosphorus combines readily, almost violently, with the 
bromine as soon as the vapor of the latter, aided by a little warmth 
from a flame, rises to the region of the phosphorus. The bromide 
of phosphorus thus formed then suffers decomposition by the water 
of the moist glass, phosphoric and phosphorous acids being pro- 
duced. The hydrobromic acid gas passes over (heat being applied 
in the after part of the operation), and may be condensed in water BROMIDES. 
or in solution of ammonia. The latter solution on evaporation 
yields bromide of ammonium. 
Other Methods.—One hundred parts of sodium hyposulphite, fifty 
of bromine, and ten of water, are placed in a flask and the generated 
gas is conducted into the upper portion of 140 parts of water con- 
tained in another vessel. When the gas begins to come over slowly, 
gentle heat is applied. The product is nearly 190 parts of liquid 
containing 25 per cent, of real acid; specific gravity 1.204. It 
should be kept in a cool dark place {Hager). Squibb prefers to 
decompose solution of bromide of potassium by sulphuric acid, 
and, after removal of potassium sulphate by crystallization, to 
distil the residual fluid. Wade prescribes an almost pure clear 
solution of the acid made by shaking together 120 grains of bro- 
mide of potassium and 153 grains of crystallized tartaric acid in 1 
ounce of distilled waiter, and setting aside till precipitation of acid 
tartrate of potassium ceases. Goebel decomposes bromide of barium 
by an equivalent weight of sulphuric acid; preparing the bromide 
of barium by heating a wret mixture of bromide of ammonium and 
carbonate of barium until carbonate of ammonium fumes cease to 
be evolved. Fletcher prefers to pass sulphuretted hydrogen gas 
through water containing bromine, and, when all bromine has dis- 
appeared, distilling the mixture. The distillate, when diluted until 
it has a sp. gr. of 1.300, contains 34 per cent, of IIBr. 
10Br2 + 4H2S + 8H20 = 20IIBr + 2IT,S04 + S2. 
Acidum Hgdrobromicum Dilutum, U. S. P., has a sp. gr. of 1.077 
and contains 10 per cent, of IIBr. 
Bromide of Potassium (KBr) is occasionally employed in phar- 
macy, and is the salt, therefore, which may he used in studying the 
reactions of this acidulous radical. The official method of making 
the salt has been alluded to under the salts of potassium (page 76). 
Other Bromides are seldom used; they may be prepared in the 
same way as, and closely resemble, the corresponding chlorides or 
iodides. Bromide of Sodium (Sodii Bromidum, U. S. P.) crystal- 
lizes in anhydrous cubes (NaBr) from solutions at 110° or 120° F., 
and in hydrous prisms (NaBr,2H20) at ordinary temperatures. 
Bromide of Ammonium (AmBr) (Ammonii Bromidum, U. S. P.) is 
prepared by agitating iron wire with a solution of bromine until the 
odor of bromine can be no longer perceived, adding solution of am- 
monia, filtering, and evaporating the filtrate to dryness. It forms a 
white granular salt, which becomes slightly yellow on exposure to 
air, is readily soluble in water, less so in spirit, and, when heated, 
sublimes. Bromide or Iodide of Ammonium may also be made by 
mixing equivalent quantities of strong hot, aqueous solutions of the 
corresponding potassium salts and of sulphate of ammonium. To 
the cooled liquids rectified spirit is added, which precipitates the 
sulphate of potassium. The spirit recovered by distillation of the 
clear liquid leaves the required salt as a residue in the retort. 
Bromide of Calcium, CaBr2 (Calcii Bromidum, U. S. P.), may be 
prepared by neutralizing hydrochloric acid by hydrate or carbonate 
of calcium, filtering, and evaporating to dryness; or by uniting bro- 268 
SALTS OF ACIDULOUS RADICALS. 
mine with iron, boiling the aqueous solution with lime until the 
mixture is red, filtering and evaporating. It is a white deliques- 
cent granular salt, soluble in water and in alcohol. 
Solution of Bromine, B. P., 10 minims in 5 ounces, is an aqueous 
solution, bromine being slightly soluble in water. 
HypobromiteSi Bromates, Perhromates, analogous to hypochlorites, 
chlorates, and perchlorates, are producible. 
Bromates occurring as an impurity in bromides are detected by 
dropping diluted sulphuric acid on to the salt, when a yellow color, 
due to free bromine, is produced immediately if bromates are pres- 
ent. 
First Analytical Reaction,—To a few drops of solution of a 
bromide (KBr, or NH+Br) add solution of nitrate of silver; a 
yellowish-white precipitate of bromide of silver (AgBr) falls. 
Treat the precipitate successively with nitric acid and dilute 
ammonia, as described for the chloride of silver ;• it is only 
sparingly dissolved by the ammonia. 
Second Analytical Reaction.—To solution of a bromide add 
a drop or two of chlorine-water or a bubble or two of chlorine 
gas; then add a few drops of chloroform or ether, or disulphide 
of carbon, shake the mixture, and set the test-tube aside; the 
chlorine, from the greater strength of its affinities, liberates the 
bromine, which is dissolved by the chloroform or ether, the 
solution falling to the bottom of the tube in the case of the 
heavy chloroform, or rising to the top in the case of the light 
ether. Either solution has a distinct yellow or reddish-yellow 
or red color, according to the amount of bromine present. 
Analytical Reactions ( Tests'). 
Note.—This reaction serves for the isolation of bromine when 
mixed with many other substances. Excess of chlorine must be 
avoided, as colorless chloride of bromine is then formed. Iodides 
give a somewhat similar but more violet appearance; the absence 
of iodine must therefore be insured by a process given in the next 
section. The above solution in chloroform or ether may be re- 
moved from the tube by drawing up into a pipette (small pipe—a 
narrow glass tube, usually having a bulb or expanded portion in 
the centre) the bromide fixed by the addition of a drop of solution 
of potash or soda, the chloroform or ether evaporated off, and the 
residue tested as described in the next reaction. 
The above operation is frequently employed for synthetical pur- 
poses. 
Third Analytical Reaction.—Liberate bromine from a bro- 
mide by the cautious addition of chlorine or chlorine-water, 
then add a few drops of cold decoction of starch ; a yellow 
combination of bromine and starch, commonly termed “ bro- 
mide of starch,” is formed. IODIDES. 
Decoction of starch is made by rubbing down two or three 
grains of starch with some drops of cold water, then adding 
much more water and boiling the mixture. 
The above, reaction may be varied by liberating the bromine 
by a little black oxide of manganese and a drop of sulphuric 
acid, the upper part of the inside of the test-tube being smeared 
over with some thick decoction of starch or thin starch-paste. 
Even sulphuric acid alone, if strong, liberates bromine from a 
bromide, the hydrogen of the hydrobromic acid first produced 
uniting with the oxygen of the sulphuric acid—-the latter being 
reduced to sulphurous acid or even to hydrosulphuric acid. 
HYDRIODIC ACID AND OTHER IODIDES. 
Formula of Ilydriodic Acid III. Molecular weight 127.6. 
Source.—The acidulous radical of hydriodic acid and other iodides 
is the element iodine (I). It occurs in nature chiefly as iodide of 
sodium and of magnesium in sea-water. Seaweeds, sponges, and 
other marine organisms, which derive much of their nourishment 
from sea-water, store up iodides in their tissues, and it is from the 
ashes of these that supplies of iodine (Iodum, U. S. P.) are ob- 
tained. 
Process.—The seaweed ash or help is treated with water, insoluble 
matter thrown away, and the decanted liquid evaporated and set 
aside to allow of the deposition of most of the sulphates, carbonates, 
and chlorides of sodium and potassium. The residual liquor is treated 
with excess of sulphuric acid, which causes evolution of carbonic and 
sulphurous or sulphuretted gases, deposition of sulphur and more 
sulphate of sodium, and formation of hydriodic acid. To the de- 
canted liquid is added black oxide of manganese, and the mixture is 
then slowly distilled ; the iodine sublimes, and is afterwards purified 
by re-sublimation. 
2III + Mn02 + II2S04 = MnS04 + 2II20 + I2. 
The analogy of chlorine, bromine, and iodine is well indicated by 
the fact that each is obtained from its compounds by the same reac- 
tion. Iodine is liberated from any iodide as bromine from bromides, 
or chlorine from chlorides—namely, by the action of black oxide of 
manganese and sulphuric acid. 
Properties.—Iodine is a crystalline purplish-black substance; its 
vapor, readily seen on heating a fragment in a test-tube, is dark 
violet. Its vapors are irritating to the lungs; but a trace may be 
inhaled with safety ( Vapor Iodi, B. P.). It melts at 239°, boils at 
about 392° F., and is entirely volatilized, the first portions containing 
any cyanide of iodine that may be present. The latter body occurs 
in slender colorless prisms, emitting a pungent odor. 
“ A solution of Iodine in chloroform should be perfectly clear and 
limpid (abs. of moisture). When shaken with distilled water, it 
should not communicate to the latter more than a light brownish 270 
SALTS OF ACIDULOUS RADICALS. 
tinge, and no deep brown color (abs. of chloride of iodine). If the 
Iodine be removed from this dilute aqueous solution by agitation 
with disulphide of carbon, and, after the separation of the latter, 
some dilute solution of ferrous sulphate with a trace of ferric chloride 
be added, finally solution of soda, and the whole supersaturated with 
hydrochloric acid, no blue precipitate should make its appearance 
(abs. of cyanide of iodine). If Iodine be dissolved in sulphurous 
acid, the solution strongly supersaturated with ammonia, and com- 
pletely precipitated by nitrate of silver, the filtrate, on being super- 
saturated with nitric acid, should not at once become more than 
faintly cloudy (abs. of more than traces of chlorine or bromine).” 
U. S. P. 
This latter reaction is applied for the detection of chloride or 
bromide in Iodides, omitting the addition of sulphurous acid. 
Quantivalence.—The atom of iodine, like those of bromine and 
chlorine, is univalent* (F). The atomic weight of iodine is 126.6, its 
molecular formula I2. 
The Iodide of Hydrogen, or Hydriodic Acid, is a heavy, colorless 
gas. Its solution in water may be made by passing sulphuretted 
hydr.ogen through water in which iodine is suspended. 
2II2S + 2I2 = S2 + 4III. 
Kolbe prepares hydriodic acid by adding to 10 parts of iodine con- 
tained in a iiask, in an atmosphere of carbonic acid gas, 1 part of 
phosphorus, little by little and slowly. On the mixture of di- and 
tri-iodide of phosphorus are poured 4 parts of water. From this 
abundance of hydriodic acid is evolved on the application of gentle 
heat, and it is not contaminated by free iodine. Phosphoric acid 
remains. 
Or iodine may be dissolved in bisulphide of carbon in a tall 
cylinder, water added, and sulphuretted hydrogen passed through 
the mixture. The water dissolves the hydriodic acid, the bisulphide 
retaining the separated sulphur. The aqueous solution only needs 
boiling for two or three minutes to remove excess of sulphuretted 
hydrogen.— Winkler. 
Syrupus Acidi Hydriodici, U. S. P., contains 1 per cent, of real 
acid. 
Iodide of potassium (KI) is largely used in medicine, and hence is 
the most convenient iodide on which to experiment in studying the 
* There is a compound of iodine having the formula IC13. Iodine 
would at first sight, therefore, seem to be a trivalent element (\'/r); 
and bromine and fluorine, from their close chemical analogy with 
iodine, would necessarily be regarded as tri valent also. From this 
aspect the position of chlorine would he anomalous. Possibly, how- 
ever, the compound is only a molecular combination of chloride of 
iodine, IC1, with chlorine, Cl2. Iodine also forms with iodide of potas- 
sium a periodide, or tri-iodide, KI3, which may be obtained in lustrous 
prismatic crystals. This, too, may have the formula KI,I2. A mer- 
curic hexiodide (IIgI6, perhaps IIgI2,I2,l2) is also known ; and a per- 
iodide of ammonium, NH^I^lj. IODIDES. 
271 
reactions of this acidulous radical. Solid iodine itself might be taken 
for the purpose; but its use and action in that state have already 
been alluded to in describing the iodides of potassium, cadmium, 
and mercury; its analytical reactions in the combined condition are 
those which may now occupy attention. 
Solution of Iodine.—Iodine is slightly soluble in water (iodine- 
water), and readily soluble in an aqueous solution of iodide of 
potassium. Five parts of iodine and 10 of iodide of potassium 
dissolved in 85 of distilled water, form Liquor Iodi Compositus, 
U. S. P. (“Lugol’s Solution’'); 4 parts of iodine and l of iodide of 
potassium, rubbed with 2 parts of water and 93 of benzoated lard 
form Unguentum Iodi, U. S. P. It is more soluble in spirit (Tine- 
tura Iodi, U. S. P.), or in a spiritous solution of iodide of potassium 
(Tinctura Iodi, B. P.). It combines with sulphur, forming an un- 
stable grayish-black solid iodide (S2I2), having a radiated crystalline 
structure (Sulphuris Iodidum, U. S. P.). If 100 parts be thoroughly 
boiled with water, the Iodine will pass off in vapor, and about 20 
parts of sulphur remain.—B. P. and U. S. P. 
Analytical Reactions ( Tests). 
First Analytical Reaction.—To a few drops of an aqueous 
solution of an iodide (e. g., KI) add solution of nitrate of sil- 
ver ; a light yellow precipitate of iodide of silver (Agl) falls. 
Four away the supernatant liquid and treat the precipitate Avith 
nitric acid, it is not dissolved; pour away the acid and then add 
dilute ammonia, it is only sparingly dissolved. 
This reaction is useful in separating iodine from most other acid- 
ulous radicals, but does not distinguish iodine from bromine. 
The presence of chloride in iodide of silver may be detected by 
boiling with dilute solution of carbonate of ammonium, filtering off 
the insoluble iodide of silver and saturating the filtrate with nitric 
acid; any chloride of silver is then precipitated. 
Ammonia, it will be remembered, dissolves chloride of silver 
readily ; hence the presence of chloride of potassium in bromide or 
iodide may be detected by dissolving in water, adding excess of 
nitrate of silver, collecting the precipitate, \\rashing, digesting in 
ammonia, filtering, and adding excess of nitric acid to the filtrate; 
a white curdy precipitate indicates a chloride (of potassium). Bro- 
mide and iodide of silver are, however, slightly soluble in ammonia. 
A better process is given on page 273. 
Second Analytical Reaction.—Liberate iodine from an iodide 
by the cautious addition of chlorine, then add cold decoction 
of starch; a deep-blue combination of iodine and starch, com- 
monly termed “ iodide of starch,” is formed. 
Starch is highly sensitive to the action of iodine; this reaction is 
consequently very delicate and characteristic. The reaction is not 
observed in hot liquids. Excess of chlorine must be avoided, or 272 
SALTS OF ACIDULOUS RADICALS. 
colorless chloride of iodine will he produced. Nitrous acid, or a 
nitrite acidulated with sulphuric acid, may be used instead of chlo- 
rine. Concentrated sulphuric acid also liberates iodine from iodides, 
the hydrogen of the hydriodic acid first produced uniting with the 
oxygen of the sulphuric acid—the latter (I12S04) being reduced to 
sulphurous acid (112803) or even to hydrosulphuric acid (II2S). 
In testing bromine for iodine the bromine must be nearly all re- 
moved by dilute solution of sulphurous acid before the decoction of 
starch is added. 
Ozone (03).—Papers soaked in mucilage of starch containing 
iodide of potassium form a test for free chlorine and nitrous acid, 
and are also employed by meteorologists to detect an allotropic or 
physically polymeric and energetic form of oxygen termed by 
Schbnbein ozone (from oCw, 020, I smell). This substance liberates 
iodine from iodide of potassium (with formation of iodide of starch), 
and is supposed to occur normally in the atmosphere, the salubrity 
or insalubrity of which is said to be dependent to some extent on 
the presence or absence of ozone. The possible occurrence of 
nitrous or chlorinoid gases in the air, however, renders the test 
untrustworthy. Ilouzeau proposes to test for ozone by exposing 
litmus-paper of a neutral tint soaked in a dilute solution of iodide 
of potassium ; the potash set free by action of the ozone turns the 
paper blue. The same paper without iodide would indicate the 
extent to which the effect might be due to ammonia vapor. Ozone, 
or rather ozonized air, is produced artificially in large quantities on 
passing air through a box (Beane's Ozone-generator) highly charged 
with electricity. In the latter operation condensation of the volume 
of air, or, rather, of the oxygen in the air, occurs. Small quantities 
are obtained by exposing in a loosely closed bottle a stick of phos- 
phorus partially covered by water, but the product is mixed with 
peroxide of hydrogen. Ozone is a powerful bleaching, disinfecting, 
and general oxidizing agent; insoluble in water, soluble in oils of 
turpentine, cinnamon, and some other liquids. From experiments 
that have been made by Soret on the specific gravity of ozone, its 
molecular formula would seem to be 03, that of ordinary oxygen 
being 02. Its smell is peculiar. (See p. 235, also “ Blood.'') 
Third Analytical Reaction.—To a neutral aqueous solution 
of an iodide, add a solution containing one part of sulphate of 
copper to two and a half parts of green sulphate of iron, and 
well shake ; a dirty-white precipitate of cuprous iodide (Cu2I2) 
falls. 
2KI + 2CuS04 + 2FeS04 = Cu2I2 + K2S04 + Fe23S04. 
Or to the liquid containing an iodide add the solution of cop- 
per sulphate and some solution of sulphurous acid, and warm 
the mixture, cuprous iodide falls. 
2KI + 2CuS04 + II2SO, + H.,0 = Cu2I2 + 2KHS0, 
+ h2so4. 273 
IODIDES. 
Separation of Chlorides, Bromides, and Iodides.—Chlorides and 
bromides are not affected in this way ; the reaction is useful, there- 
fore, in removing iodine from a solution in which chlorides and bro- 
mides have to be sought. The total removal of iodine by the former 
of the two modifications of the process is insured by supplementing 
the addition of the cupric and ferrous sulphates by a few drops of 
solution of potash or soda, any acid which might be keeping cuprous 
iodide in solution being thereby neutralized, ferric or ferrous hy- 
drate, precipitated at the same time, not affecting the reaction. 
Occasionally, too, it may be necessary to repeat the process with the 
filtrate before the last traces of iodine are removed. The second 
modification of the process is, on the whole, to be preferred. 
Chloride of the rare metal palladium performs a similar useful 
office in removing iodine, but not bromine or chlorine, from solu- 
tions. 
Chlorides may be separated from bromides by taking advantage 
of the ready solubility of chloride of silver, and slow and slight 
solubility of bromide of silver in ammonia, especially in (a fair, not 
a great, excess of) ammonia containing chloride of silver. 
Siebold’s test for the detection of chlorides when occurring with 
bromides is based upon the fact that a strong solution of perman- 
ganate of potassium liberates the bromine from moderately strong 
solutions of bromides containing a large excess of sulphuric acid. 
A strong solution of permanganate is added to the aqueous solution 
of bromide or iodide (containing not more than 1 in 40), strongly 
acidified by dilute sulphuric acid, until the permanganate ceases to 
be decolorized, and a copious precipitate of oxide of manganese is 
formed. The mixture is boiled for about five minutes to expel the 
bromine, and then filtered. The colorless filtrate is now quite free 
from bromine, and may be tested for chlorine by nitrate of silver. 
If a chloride be present, a small quantity of its chlorine is lost by 
this process ; but the main portion always remains, provided that 
no undue excess of the permanganate be used. It is essential, 
therefore, that the filtrate should be colorless; for if it be colored so 
as to indicate the presence of undecomposed permanganate, the loss 
of the greater part if not of the whole of the chlorine must be ex- 
pected. If, on the other hand, too little permanganate be employed, 
a trace of bromide may be left in the filtrate. If the solution under 
examination should be very much stronger than 1 in 40, water should 
be added before boiling (just after the addition of the permanga- 
nate), in order to avoid a loss of IIC1. 
Chlorides may also be detected in bromides and iodides by taking 
advantage of the formation of chlorochromic anhydride (page 236) 
and the non-occurrence of corresponding compounds of bromine or 
iodine. 
To a solution of a chloride with a bromide and an iodide 
add a concentrated solution of sulphate of sodium, and then a 
reagent prepared by mixing equal volumes of sulphuric acid 
and saturated solution of sulphate of copper, until no further 
precipitation of cuprous iodide occurs. Next add solution of 274 
SALTS OF ACIDULOUS RADICALS. 
soda to remove excess of sulphate of copper; filter and evap- 
orate to dryness. Place the dried residue, together with an 
equal bulk of red chromate of potassium, in a dry test-tube 
fitted with a delivery-tube, or into a small retort, and cover the 
mixture with sulphuric acid. Distil into water. Chromic an- 
hydride and hydrochloric and hydrobroinic acids are liberated 
by the sulphuric acid, and reacting upon one another form 
chlorochromic anhydride, together with free bromine and 
chlorine. 
Cr03 + 2HC1 = CrCl202 + II20. 
2Cr03 + 6HC1 + 3H2S04 - Cr23S04 + 3C12 + 6H20. 
2Cr03 + 6HBr + 3H2S04 = Cr23S04 + 3Br2 + 6H20. 
The chlorochromic anhydride is decomposed by the excess 
of water into which it falls, giving rise to chromic acid, which 
imparts its color to the liquid, and hydrochloric acid. 
CrCl202 + 2H,0 =- II,Cr04 + 2HC1. 
The chlorine escapes and the bromine is dissolved by the 
water. The colored liquid is then shaken with chloroform, 
which removes the bromine—indicating bromine in the origi- 
nal substance. A yellow color remaining is due to chromic 
acid, indicating chlorides in the original substance. Or add 
ammonia to the distillate—the color due to bromine is thereby 
entirely removed, while that of the chromic compound is only 
slightly modified. 
Fourth Analytical Reaction.—Iodides have been shown to 
be useful in testing for mercuric salts (see the Mercury reac- 
tions, p. 201) ; a mercuric salt (corrosive sublimate, for ex- 
ample) may therefore be used in testing for iodides, a scarlet 
precipitate of mercuric iodide (Hgl2) being produced. 
This reaction may be employed where large quantities of an 
iodide are present; but its usefulness in analysis is much im- 
paired by the fact that the precipitate is soluble in excess cf the 
dissolved iodide or in excess of the mercuric reagent. Its color and 
insolubility in water distinguish it from mercuric chloride, bromide, 
and cyanide, which are white soluble salts. 
Fifth Analytical Reaction.—Iodides have also (see the Lead 
reactions, p. 211) been shown to be useful in testing for lead 
salts; similarly a lead salt (acetate, for example) may be used 
in testing for iodides, a yellow precipitate of iodide of lead 
(Pbl2), soluble in hot water and crystallizing in yellow scales 
on cooling, being produced. 
Chloride, bromide, and cyanide of lead are white; hence the above 
reaction may occasionally be useful in distinguishing iodine from the CYANIDES. 
275 
allied radicals. But iodide of lead is slightly soluble in cold Avater; 
hence small quantities of iodide cannot be detected by this reaction. 
(For lodates see p. 293.) 
Analogies between Chlorine, Bromine, Iodine, and their Compounds. 
—These elements form a natural group or family, each distinct from 
the other, yet closely related. Moreover, their dissimilarities are so 
curiously gradational as to irresistibly suggest the idea that some 
day we may find the differences between these bodies to be in de- 
gree rather than in kind. Thus chlorine is a gas and iodine a 
solid, while bromine occupies the intermediate condition. The 
atomic weight of bromine is nearly midway between those of 
chlorine and iodine. The same may be said of the weight of 
equal volumes of each in the gaseous state. The specific gravity 
of fluid chlorine is 1.33, of iodine 4.95, while bromine is nearly 3. 
Liquid chlorine is transparent, iodine opaque, bromine intermediate. 
The crystalline forms of the chloride, bromide, and iodide of a metal 
are commonly identical. One volume of either element in the gas- 
state combines with an equal volume of hydrogen (at the same 
temperature) to form two volumes of a gaseous acid, very soluble in 
water (hydrochloric acid, hydrobromic acid, hydriodic acid). Many 
other analogies are traceable. 
419. State the method by which Bromine is obtained from its nat- 
ural compounds. 
420. Mention the properties of bromine. 
421. IIow may the Bromides of Potassium and Ammonium be 
made ? 
422. By what reagents may bromides be distinguished from chlo- 
rides? 
423. Whence is iodine obtained ? 
424. By what process is iodine isolated ? 
425. State the properties of iodine. 
42(5. What is the nature of Iodide of Sulphur? 
427. Give the analytical reaction of iodides. 
428. Which three substances may indirectly be detected by a mix- 
ture of iodide of potassium and mucilage of starch? 
429. Describe a method by which iodides may be removed from a 
solution containing chlorides and bromides. 
QUESTIONS AND EXERCISES. 
HYDROCYANIC ACID AND OTHER CYANIDES. 
Formula of Hydrocyanic Acid IICN or HCy. 
Molecular weight 27. 
History of Cyanogen.—The acidulous radical of hydrocyanic acid 
and other cyanides is a compound body, cyanogen (Cy). It is so 276 
SALTS OF ACIDULOUS RADICALS, 
named from uvavoc, Tcuanos, blue, and yevvau, gennao, I generate, in 
allusion to its prominent chemical character of forming, with iron, 
the different varieties of Prussian blue. It was from Prussian blue 
that Scheele, in 1782, first obtained what we now, from our know- 
ledge of its composition, term hydrocyanic acid, but which he called 
Prussic acid. Cyanogen was isolated by Gay-Lussac in 1814, and 
was the first compound radical distinctly proved to exist. 
Sources.—Cyanogen does not occur in nature, and is only formed 
from its elements under certain circumstances. It is found in small 
quantities among the gases of iron-furnaces, and is produced to a 
slight extent in distilling coals for gas. In the form of ferrocyanide 
of potassium it is obtained abundantly by heating animal refuse 
containing nitrogen, such as the scrapings of horns, hoofs, and 
hides (5 parts), with carbonate of potassium (2 parts) and waste iron 
(filings, etc.) in a covered iron pot. The residual mass is boiled with 
water, the mixture filtered, and the filtrate evaporated and set aside 
for crystals to form. The cyanogen, produced from the carbon and 
nitrogen of the animal matter, unites with the potassium, and after- 
wards, on boiling with water, with iron, to form what is known as 
the yellow prussiate of potash (Potassee Prussias Flava, B. P.), or 
ferrocyanide of potassium (K/4Fe//Cy/6,3II20) (Potassii Ferrocyani- 
dum, U. S. P.), a compound occurring in four-sided tabular yellow 
crystals. It contains the elements of cyanogen, yet it is not a 
cyanide, for it is not poisonous, and is otherwise different from 
cyanides; it will be further noticed subsequently. From this salt 
all cyanides are directly or indirectly prepared. 
Cyanide of potassium (KCy) (Potassii Cyanidu,m,\J. S. P.), which 
is the most common, is procured by fusing 8 parts of ferrocyanide 
with 3 of carbonate of potassium in a crucible; carbonic acid gas 
(C02) is evolved, iron (Fe) is set free, and cyanate of potassium 
(IvCyO), a body that will be subsequently noticed, is formed at the 
same time:— 
Double cyanides exist, such as the cyanide of sodium and silver 
(NaCy,AgCy), formed in the process (subsequently described) of 
quantitatively determining the amount of hydrocyanic acid in a 
liquid by a standard solution of nitrate of silver; these compounds 
have, more or less, the properties of their constituents. But other 
cyanogen compounds, not double cyanides, occur in which the cyano- 
gen is so intimately united with a metal as to form a distinct radical; 
such are ferrocyanides and ferridcyanides—salts which will be noticed 
in due course. 
Cyanogen, like chlorine, bromine, and iodine, is univalent (Cy/). 
It may be isolated by simply heating mercuric cyanide (HgCy2) or 
cyanide of silver (AgCy). It is a colorless gas, burning, when 
ignited, with a beautiful peach-blossom-colored flame. 
Mercuric cyanide is produced in crystals on dissolving 1 part of 
ferrocyanide of potassium in 15 parts of boiling water, adding 2 parts 
of mercuric sulphate, keeping the whole hot for ten or fifteen minutes, 
and then filtering and setting aside to cool. In addition to mercuric 
2K4FeCy6 + 2K2C03 = lOKCy + 2KCyO + Fe2 + 2CO.r CYANIDES. 
277 
cvanide (HgCy2), mercury (Hg), ferric sulphate (Fe23S04), and sul- 
phate of potassium (K2S04), are formed. Any excess of ferrocyanide 
also gives Prussian blue by reaction with the ferric sulphate. It 
(Hi/drargyri Cyanidum, U. S. P.) may also be made by dissolving 
red oxide of mercury in diluted hydrocyanic acid. A small flame 
of cyanogen may be obtained on heating a few crystals of mercuric 
cyanide in a short piece of glass tubing closed at one end, and apply- 
ing a light to the other end as soon as evolution of gas commences; 
brown paracyanogen (C3N3) and mercury remain. 
Reactions. 
Diluted Hydrocyanic Acid. 
Synthetical Reaction.—Dissolve 2 or 3 grains of ferrocyanide 
of potassium in 5 or 6 times its weight of water in a test-tube, 
add a few drops of sulphuric acid and boil the mixture, con- 
veying the evolved gas by a bent glass tube (adapted to the 
test-tube by a cork) into another test-tube containing a little 
water; the product is a dilute solution of hydrocyanic acid. 
Made by this process in large quantities of a certain definite 
strength (2 per cent.), this solution is the Acidum Hydrocy- 
anicnm Dilution, U. S. P. “ A colorless liquid of a peculiar 
odor. Specific gravity 0.997.” 
2K4FeCy6 + 6H2S04 = FeK2Fe"Cy6 + 6KHS04 + 6IICy. 
The following are the details of the official (U. S. P.) process:— 
Place 20 parts of Ferrocyanide of Potassium in coarse powder in 
a tubulated retort, and add to it forty (40) parts of Water. Con- 
nect the neck of the retort (which is to be directed upward), by 
means of a bent tube, with a well-cooled condenser, the delivery- 
tube of which terminates in a receiver surrounded with ice-cold 
water, and containing sixty (60) parts of Diluted Alcohol. All the 
joints of the apparatus, except the neck of the receiver, having 
been made air-tight, pour into the retort, through the tubulure, the 
Sulphuric Acid previously diluted with an equal weight of Water. 
Agitate the retort gently, and then heat it, in a sand-bath, until the 
contents are in brisk ebullition, and continue the heat regularly 
until there is but little liquid mixed with the saline mass remaining 
in the retort.* Detach the receiver, and add to its contents so much 
Distilled Water as may be required to bring the product to the 
strength of tico (2) per cent, of absolute Hydrocyanic Acid. ( Vide 
paragraphs on quantitative analysis.) 
* This operation is peculiarly liable to those sudden and tumultuous 
evolutions of vapor, or “bumpings,” or “ soubresauts,” which often in- 
terfere with successful distillation. Such phenomena occur, according 
to Tomlinson, whenever unaided heat has to overcome the great amount 
of adhesion naturally existing between certain liquids and vapors, or, 
rather, between the normal liquid and those particles of it which, be- 278 
SALTS OF ACIDULOUS RADICALS. 
The residue of this reaction is acid sulphate of potassium (KTIS04), 
which remains in solution, and ferrocyanide of potassium and iron 
(Fe//K2FeCy6), an insoluble powder sometimes termed Everitt’s 
yellow salt, from the name of the chemist who first made out the 
nature of the reaction. The latter compound becomes bluish-green 
during the reaction, owing to absorption of oxygen. 
Diluted hydrocyanic acid may also be prepare d by reaction of 
cyanide of silver (6 parts), hydrochloric acid (5 parts), and distilled 
water (55 parts). Mix the hydrochloric acid with the distilled 
water, add the cyanide of silver, and shake the whole together in a 
glass-stoppered bottle. When the precipitate has subsided, pour off 
the clear liquid. 
Pure anhydrous hydrocyanic acid is a colorless, highly volatile, 
intensely poisonous liquid, solidifying when cooled to a low tempera- 
ture.* It may be made by passing sulphuretted hydrogen over mer- 
curic cyanide. The official solution of the acid is fairly stable, but 
is said to be rendered more so by the presence of a minute trace of 
sulphuric or hydrochloric acid. A stronger acid is liable to assimilate 
the elements of water, and yield formiate of ammonium (NII4CII02). 
Solutions of hydrocyanic acid often become brown by formation of 
what is, apparently, paracyanogen (C3N.t). According to Williams, 
aqueous hydrocyanic acid containing 2U per cent, of glycerin can 
coming strongly heated at the heated part of the vessel, have assumed 
the condition of particles of dissolved vapor, and which would at once 
pass from this condition into that of permanent vapor but for adhesion. 
Ordinarily a ghiss or other surface is not absolutely clean, but is more 
or less covered with specks, traces of materials deposited from the air, 
the fingers, cloths, etc. Some liquids seem to have little or no adhesion 
for these materials, while certain vapors have greater adhesion for the 
films than for the liquids. Hence, in ordinary regular ebullitions the 
vapors accumulate on the films, and then at once become subject to the 
pressure of the mass of fluid, and so pass off in bubbles. But when 
the films are absent, or have become removed during distillation, the 
heat accumulates until it is sufficient to overcome the adhesion of the 
superheated particles, and these are then, all of them at once, con- 
verted into vapor, the liquid commonly boiling over, sometimes even 
bursting the vessel. “Bumping” would be prevented by the intro- 
duction of fragments of substances for which vapor-particles have ad- 
hesion, but no known substance has this property in an absolute degree. 
Fragments of tobacco-pipe or pumice stone, pieces of cork, thick paper, 
resin, sulphur, platinum wire, etc., are all useful when there is no 
chemical action between them and the liquid. Mr. Tomlinson very 
strongly recommends cocoanut-shell charcoal to be used whenever 
practicable. A slow current of gas, such as hydrogen, air, or carbonic 
acid gas. also usefully promotes escape of vapor from a liquid. A jet 
of steam prevents bumping, but is not always applicable. When the 
bumping cannot well be prevented, as in the distillation of sulphuric 
acid, it is somewhat reduced in violence if the retort be heated by an 
annular gas-burner rather than by a single central jet. 
* Traces are formed when electricity passes between carbon poles in 
slightly moist air (Dewar). CYANIDES. 
279 
be kept for an apparently indefinite length of time. The official 
acid should be preserved in small stoppered bottles in a cool dark 
place. 
Note.—A few drops of diluted hydrocyanic acid so placed that its 
vapor may be inhaled, forms the Vapor Acid Hydrocyanici, B. P., 
or Inhalation of Hydrocyanic Acid. 
Hydrocyanic acid also occurs in cherry-laurel water and bitter- 
almond water (vide Index). 
The hydrocyanic acid used in pharmacy is extremely liable to vari- 
ation in strength. It should frequently be tested volumetrically. 
First Analytical Reaction.—To a few drops of the hydro- 
cyanic acid solution produced in the above reaction, or to any 
solution of a cyanide, add excess of solution of nitrate of sil- 
ver ; a white precipitate of cyanide of silver (AgCy) falls. 
When the precipitate has subsided, pour away the supernatant 
liquid, and place half of the residue in another test-tube: to 
one portion add nitric acid, and notice that the precipitate does 
not dissolve; to the other add ammonia, and observe that the 
precipitate is insoluble or only sparingly soluble. (Chloride 
of silver, which is also white, is readily soluble in ammonia.) 
Cyanide of silver dissolves in solutions of cyanides of alkali- 
metals, soluble double cyanides being formed (c. g., KCy,- 
AgCy). 
Solubility of precipitates in strong solutions of salts.—Cyanide 
of silver and many other precipitates insoluble in acids (similar re- 
marks apply to precipitates insoluble in alkalies) are often soluble 
in the strong saline liquids formed by the addition of acids and 
alkalies to one another. Hence the precaution of adding the latter 
reagents to separate portions of a precipitate, or of not adding the 
one until the other has been poured away. 
Cyanogen in an insoluble cyanide, such as cyanide of silver itself, 
is readily recognized on heating the substance in a short piece of 
glass tubing closed at one end like a test-tube and drawn out at the 
other end, so as to have but a small opening; on applying a flame, 
the escaping cyanogen ignites and burns with a characteristic peach- 
blossom tint. Metallic silver remains. 
Analytical Reactions ( Tests). 
Antidote. 
Second Analytical Reaction.—To a dilute solution of hydro- 
cyanic acid, or a soluble cyanide, add a few drops of solution 
of a ferrous salt and a drop or two of solution of a ferric salt 
(ferrous sulphate and ferric chloride are usually at hand) ; to 
the mixture add potash or soda (magnesia or carbonate of so- 
dium), and then hydrochloric acid; a precipitate of Prussian 280 
blue remains. The decompositions may be traced in the fol- 
lowing equations:— 
SALTS OF ACIDULOUS RADICALS. 
HCy + KIIO = KCy + H20 
2KCy + FeS04 = FeCy + K2S04 
4KCy + FeCy2 = K4FeCy6 or K4Fcy 
3K4Fcy + 2Fe2Cl6 = 12KC1 + Fe4Fcys. 
The test depends on the conversion of the cyanogen into ferro- 
cyanogen by aid of the iron of a ferrous salt, and the combination 
of the ferrocyanogen, so produced, with the iron of a ferric salt. 
Hence a mixture of green sulphate of iron, solution of perchlo- 
ride of iron, and either magnesia or carbonate of sodium, is the 
recognized antidote in cases of poisoning by hydrocyanic acid or 
cyanide of potassium. 
In such an alkaline mixture the poisonous cyanide, by reaction with 
ferrous hydrate, is at once converted into innocuous ferrocyanide of 
potassium or sodium, etc.; should the mixture become acid, the fer- 
ric salt present reacts with the soluble ferrocyanide, forming insol- 
uble Prussian blue, which is also inert. From the rapidity of the 
action of these poisons, however, there is seldom time to prepare an 
antidote. Emetics, the stomach-pump, the application of a stream 
of cold water to the spine, and the above antidote, form the usual 
treatment. 
Third Analytical Reaction.—To solution of hydrocyanic 
acid add ammonia and common yellow sulphydrate of ammo- 
nium, and evaporate the liquid nearly or quite to dryness in a 
small dish, occasionally adding ammonia till the excess of 
sulphydrate of ammonium is decomposed; add water and 
acidify the liquid with hydrochloric acid, and then add a drop 
of solution of a ferric salt; a blood-red solution of sulpho- 
cyanide of iron will be formed. 
This is a very delicate reaction. Some free sulphur in the yellow 
sulphydrate of ammonium unites with the alkaline cyanide and forms 
sulphocyanate (2AmCy -f- S2 = 2AmCyS); the ammonia combines 
with excess of free sulphur, and forms, among other salts, sulphydrate 
of ammonium, the whole of which is removed by the ebullition. If 
the liquid has not been evaporated far enough, sulphydrate of am- 
monium may still be present, and give black sulphide of iron on the 
addition of ferric salt. 
Hydrocyanic Acid in the Blood.—According to Buchner the blood 
of animals poisoned by hydrocyanic acid, instead of coagulating as 
usual, remains liquid and of a clear cherry-red color several days. 
In one case he obtained the reactions of the acid on diluting and dis- 
tilling the blood fifteen days after death, and applying the usual 
reagents to the distillate. A queous solution of peroxide of hydrogen 
(p. 102) changes such blood to a deep-brown color. 
Sehonhein's test for hydrocyanic acid is said to be extremely deli- NITRATES. 
281 
cate. Filtering-paper is soaked in a solution of 3 parts of guaiacum 
resin in 100 of alcohol. A strip of this paper is dipped in a solution 
of 1 part of sulphate of copper in 50 of water; a little of the sus- 
pected solution is placed on this paper and exposed to the air, when 
it immediately turns blue. Or the paper may be placed over the 
neck of an open bottle of medicine supposed to contain hydrocyanic 
acid, or otherwise exposed to the vapor of the acid. 
QUESTIONS AND EXERCISES. 
430. Write a paragraph on the history of cyanogen. 
431. Mention the source of the cyanogen of cyanides. 
432. How is Ferrocyanide of Potassium prepared ? 
433. What is the formula of ferrocyanide of potassium? 
434. Is ferrocyanide of potassium poisonous? 
435. Write an equation expressive of the reaction which ensues 
when ferrocyanide and carbonate of potassium are brought together 
at a high temperature. 
436. What are the properties of cyanogen ? How may it be ob- 
tained in a pure condition ? 
437. How is mercuric cyanide prepared ? 
438. How much real hydrocyanic acid is contained in the official 
liquid ? 
439. Give details of the preparation of hydrocyanic acid, and an 
equation of the reaction. 
440. State the proportion of water that must be added to an aque- 
ous solution containing 15 per cent, of hydrocyanic acid to reduce 
the strength to 2 per cent.—Ans. 6J to 1. 
441. What are the characters of pure undiluted hydrocyanic acid? 
How may it be obtained? 
442. Enumerate the tests for cyanogen, giving equations. 
443. Explain the action of the best antidote in cases of poisoning 
by hydrocyanic acid or cyanide of potassium. 
Formula of Nitric Acid IINOa. Molecular weight 63. 
Introduction.—The group of elements represented by the formula 
N03 is that characteristic of nitric acid and all other nitrates ; hence 
it is expedient to regard these elements as forming an acidulous 
radical, which may be termed the nitric radical. Like the hypo- 
thetical basylous radical ammonium (NH4), this supposed acidulous 
radical (N03) has not been isolated. Possibly it is liberated when 
chlorine is brought into contact with nitrate of silver ; but, if so, its 
decomposition into vrhite crystalline nitric anhydride (N205) and 
oxygen (0) is too rapid to admit of its identification. 
Sources.—The nitrogen and oxygen of the air combine and ulti- 
mately form nitric acid whenever a current of electricity (as in the 
NITRIC ACID AND OTHER NITRATES. 282 
SALTS OF ACIDULOUS RADICALS. 
occurrence of lightning) passes. The nitrates found in rain may 
partly or wholly thus originate. The oxidation of ammoniacal mat- 
ter and of the nitrogenous constituents of animal and vegetable 
matter in the soil, favored by the darkness and, probably, by the 
presence of some low form of vegetable life acting as a ferment, 
result in the production of nitrates. Hence nitrates are commonly 
met with in waters, soils, and the juices of plants. In the concen- 
trated plant-juices termed medicinal “ Extracts,” small prismatic 
crystals of nitrate of potassium may occasionally be observed. (The 
cubical crystals often met with on extracts are chloride of potas- 
sium.) Nitric acid and other nitrates are obtained from nitrates of 
potassium and sodium, and these form the surface layers of the soil 
of tropical countries. Nitrate of potassium or prismatic nitre (from 
the form of its crystals) is chiefly produced in and about the villages 
of India. The natives simply scrape the surface of waste grounds, 
mud-heaps, banks, and other spots where a slight incrustation indi- 
cates the presence of appreciable quantities of nitre, mix the scrap- 
ings with wood ashes (carbonate of potassium, to decompose the 
nitrate of calcium always present), digest the mixture in water, and 
evaporate the liquor. The impure product is purified by careful 
recrystallizations, and is sent into commerce in the form of white 
crystalline masses or fragments of striated six-sided prisms. Besides 
its use in medicine (Potassii Nitras, U. S. P.), it is employed in 
very large quantities in the manufacture of gunpowder. Charta 
Potassii Nitratis, U. S. P., Nitrate-of-Potassium Paper, is made by 
immersing strips of white unsized paper in a solution of 1 part of 
the salt in 4 parts of water and drying them. Nitrate of Sodium 
(Sodii Nitras, U. S. P.) occurs in deposits from 3 inches to 3 yards 
in thickness on and near the surface, and at any depth down to 
about 30 feet, in many parts of Peru, Bolivia, and Chili, but more 
especially in the district of Atacama. The mineral is termed 
caliche, and commonly contains 50 per cent, of nitrate of sodium. 
The latter is distinguished as Chili saltpetre or (from the form of its 
crystals—obtuse rhomboids) cubic nitre, and is chiefly used as a 
manure and as a source of nitric acid, its tendency to absorb moist- 
ure unfitting it for use in gunpowder. In many parts of Europe 
nitrate of potassium is made artificially by exposing heaps of animal 
manure, refuse, ashes, and soil to the action of the air and the heat 
of the sun : in the course of a year or two the nitrogen of the animal 
matter becomes oxidized to nitrates; the latter are removed by 
washing. According to Warington, the nitrifying ferment appears 
capable of existing in three conditions:—1, the nitric ferment of 
soil, which converts both ammonium salts and nitrites into nitrates; 
2, the altered ferment, which converts ammonium salts into nitrites, 
but fails to change nitrites into nitrates; and, 3, the surface organ- 
ism (a bacterium) which changes nitrites into nitrates. 
Note.—The word nitric is from nitre, the English equivalent of 
the Greek virpov (nitron), a name applied to certain natural deposits 
of natron (carbonate of sodium), for which nitrate of potassium 
seems at first to have been mistaken. Saltpetre is simply sal petrce, 
salt of the rock, in allusion to uie natural origin of nitrate of potas- NITRATES. 
sium. Sal prunella (from sal, a salt, and pruna, a live coal) is 
nitrate of potassium melted over a fire and cast into cakes or bullets. 
The nitric radical is univalent (NO/). 
Constitution of Salts. 
It is here necessary again to caution the reader against regarding 
salts as invariably possessing a known constitution, or supposing 
that they always possess two or more sides or contain definite rad- 
icals. The erroneous conception which, of all others, is most likely 
to be imperceptibly formed is that of considering salts to be binary 
bodies. For, first, the names of salts are necessarily binary. A 
student hears the names “sulphate of iron,” “sulphate of copper,” 
and simultaneously receives the impression that each salt has two 
sides, copper or iron occupying one, and something indicated by the 
words “ sulphate of” the other. Such words as “ vitriol,” green or 
blue, or “ nitre,” would perhaps implant unitary ideas in the mind ; 
but it is simply impossible to give such names to all salts as will 
convey the impression that each salt is a whole, and therefore uni- 
tary. The name “ sulphate of potash ” produces binary impres- 
sions ; and the less incorrect name, “ sulphate of potassium,” is in 
this respect no better. Secondly, it is impracticable to study salts 
as a whole. Teachers are almost unanimous in the opinion that 
students should first master the reactions characteristic of the metals 
in salts, and then the residues which, with those metals, make up 
the salts, or vice versa. It is not only impracticable, but impossible, 
to study salts as a whole; binary ideas concerning them are there- 
fore almost inevitably imbibed. We come to regaid a salt as a body 
which splits up in one direction only, look upon nitre, for instance, 
and all other nitrates, as containing NO, and a metal K ; whereas 
KN03 may be split up into KN02 and 0; or into K20, N2, and 05; 
or may contain lv20 and N205. These are the chief disadvantages 
attending the employment of the binary hypothesis in studying 
chemical compounds; if they be borne in mind, the hypothesis may 
be freely used without much danger of permanent mental bias. 
Thus in nitre let the group of elements (N03) which, with potas- 
sium, makes up the whole salt be called the nitric radical, the name 
of the latter being directly derived from its hydrogen salt. Sim- 
ilarly allow the acidulous residues of other salts of metals to be 
termed respectively the chloric, acetic, sulphurous, sulphuric, car- 
bonic, oxalic, tartaric, phosphoric, citric, boracic radicals. In short, 
these compound radicals should be regarded as groupings common 
to many salts, and which may usually be transferred without any 
apparent breaking or splitting; at the same time we must be pre- 
pared to find that occasionally a salt divides in other directions. In 
this way perhaps erroneous impressions will gain least hold on the 
mind, and a way be left open for the easy entrance of new truths 
should the real constitution of salts be discovered. 
Formerly salts (such as sulphate of magnesium) were regarded as 
containing (a) an oxide of a metal (MgO) and an anhydride (S03), 
the latter being incorrectly called an acid (sulphuric acid); or (//) as 
containing two simple radicals (e. <j., KI, NaCl, KCy, HgS)—the 284 
SALTS OF ACIDULOUS RADICALS. 
former being called oxyacid salts, or oxysalts, and the hitter haloid 
salts (from a'Ac, als, sea-salt, and ridoc, eidos, likeness). Such dis- 
tinction is no longer maintained, the two classes being merged. 
This is an important educational gain on the side of simplicity; for, 
whereas under the old system much time was necessarily expended 
before salts of a metal and salts of the oxide of that metal could be 
distinguished (e. //., KI and K20,S03), now, all salts being regarded 
as salts of the metals themselves (e. y., KI and K2S04), no such 
distinction is necessary. 
Reactions. 
Synthetical Reaction.—To a fragment of nitrate of potassium 
or nitrate of sodium in a test-tube add a drop or two of sul- 
phuric acid, and warm ; nitric acid (HNOs) is evolved in vapor. 
The fumes may be condensed by a bent tube fitted to the test- 
tube, not by a cork as for hydrochloric acid—because the nitric 
vapors would strongly act on it—but by plaster of Paris, a 
paste of which sets hard on being set aside for a short time, 
and is unaffected by the acid. 
On a somewhat larger scale nitric acid may be prepared by 
heating, in a stoppered or plain retort, a mixture of equal 
weights of nitrate of potassium and sulphuric acid; the acid 
distils over, and acid sulphate of potassium remains behind:— 
Nitric Acid. 
Nitrate of 
potassium. 
KNO, + IT.2S04 = IIN03 + KHSO* 
Sulphuric 
acid. 
Nitric 
acid. 
Acid sulphate 
of potassium. 
Half the quantity of sulphuric acid may be taken; but in that 
case neutral sulphate of potassium (K2S04) is produced, which, from 
its hard, slightly soluble character, is removed with difficulty from 
the retort. On the manufacturing scale the less proportion is used ; 
hut instead of retorts iron cylinders are employed, from which the 
residual salt is removed by chisels. Moreover, the cheaper sodium 
salt is the nitrate, from which manufacturers usually prepare nitric 
acid, seven parts of nitrate of sodium and four of sulphuric acid 
being employed. 
Note.—The acid sulphate of-potassium is readily converted into 
neutral sulphate (Potassii Sulphas, U. S. P.) by dissolving in water, 
adding carbonate of potassium until effervescence ceases to occur, 
filtering, and setting aside to crystallize. 
Pure nitric acid (IIN03) is a colorless liquid, somewhat difficult 
of preparation ; its specific gravity is 1.52. The strongest acid met 
with in commerce has a sp. gr. of 1.5, and contains 93 per cent, of 
real nitric acid (IIN03); it fumes disagreeably, is unstable, and, 
except as an escharotic, is seldom used. The United States Phar- 
macopoeia contains two acids: Acidufn Nitricum, of sp. gr. 1.42, 
and containing 69.4 per cent, of real acid (I4N03); and another, 
Acidum Nitricum Dilutum, sp. gr. 1.059, containing 10 per cent. NITRATES. 
285 
The stronger liquid, although containing water, is usually simply 
termed “nitric acid.” The official nitric acid, of sp. gr. 1.42, is a 
definite hydrous acid (2HN03,3H20); it distils at 250° F. without 
change. If a weaker acid be heated it loses water; if a stronger 
acid be heated it loses nitric acid, until the density of 1.42 is reach- 
ed. Aqua fortis is an old name for nitric acid (Aqua fort is simplex, 
sp. gr. 1.22 to 1.25; Aqua fortis duplex, 1.36). The strength of a 
specimen of nitric acid is determined by volumetric analysis. Nitric 
anhydride (X205), sometimes but erroneously called anhydrous nitric 
arid, is a solid crystalline substance formed on passing dry chlorine 
over dry nitrate of silver. Metals reduce nitric acid to nitrous acid 
and to the various oxides of nitrogen, or even to nitrogen itself, ac- 
cording to the strength of acid, temperature, and amount of nitrate 
present. Not unfrequently nitrate of ammonium is simultaneously 
formed. Thus, with zinc :— 
Aqua Regia.—Four parts of nitric acid and fifteen of hydrochloric 
acid by weight form the Acidum Nitrohydrochloricum, U. S. P., and 
the same weights with 76 of water, give the Acidum Nitrohydro- 
chloricum llilutum. 
10HN03 + 2Zn2 = 4(Zn2N03) + NII4N03 + 3II20. 
211 NO., + 6HC1 = N.O.CL? + 411,0 + Cl2 
.1 
Nitric acid. 
Hydrochloric 
acid. 
11 » 
Chloronitric 
gas. 
Water. 
-j 
Chlorine. 
In the later stages of the reaction, the decomposition expressed in 
the following equation also probably occurs:— 
IINOj + 3IIC1 = NOC1 + 2IT20 + Cl2 
Nitric acid. 
Hydrochloric 
acid. 
Cliloronitrous 
gas. 
Water. 
Chlorine. 
The same reaction occurs if the acids are mixed after dilution, but 
is not complete for a week or a fortnight (Tilden). The undiluted 
mixture of acids is known as aqua regia, so called from its property 
of dissolving gold, “the king” of metals. 
This “diluted nitrohydrochloric acid” is quite strong enough to 
attack organic matter, with evolution of nitrous gases, hence should 
not be dispensed with tinctures, etc., in too concentrated a form. 
Analytical Reactions ( Tests'). 
First Analytical Reaction.—To a solution of any nitrate 
(e. g., KN03) add sulphuric acid, and then copper turnings, and 
warm ; colorless nitric oxide gas (NO) is evolved, which at 
once unites with the oxygen in the tube, giving red fames of 
nitric peroxide or peroxide of nitrogen (N02). 
2KN03 + 5II2S04 + Cu3 = 2NO + 3CuS04 + 4II20 + 2KIISO,; 
then, 2NO -f 02 = 2N02. 
Performed on a larger scale, in a vessel to which a delivery-tube 
is attached, the reaction of nitric acid on copper becomes of synthet- SALTS OF ACIDULOUS RADICALS. 
ical interest, being the process for the preparation of nitric oxide gas 
for the purposes of chemical experiment. 
Small amounts of a nitrate may be overlooked by this test, the 
color of the red fumes not being very intense. 
Undiluted nitric acid poured on to copper turnings gives dense red 
vapors of nitrous acid (1IN02), nitrous anhydride (N203), nitric 
peroxide (N02), nitric oxide (NO), and even nitrogen (N2), the re- 
action varying somewhat according to the temperature of the mix- 
ture and (Ackwmrth) the amount of nitrate of copper in solution. 
Diluted nitric acid gives nitric oxide, Cu3 -j- 811N03 — 3(Cu2NO 
+ 4II20 + 2NO. 
Second Analytical Reaction.—To a cold solution of the ni- 
trate, even if very dilute, add three or four crystals of sul- 
phate of iron, shake gently for a minute in order that some of 
the sulphate may become dissolved, and then pour eight or ten 
drops of strong sulphuric acid down the side of the test-tube, 
so that it may form a layer at the bottom of the vessel ; a 
reddish-purple or black coloration will appear between the acid 
and the supernatant liquid. 
This is a very delicate test for the presence of nitrates. The black 
color is due to a solution or, perhaps, combination of nitric oxide 
with a portion of the ferrous salt. The nitric oxide is liberated 
from the nitrate by the reducing action of the hydrogen of the 
sulphuric acid, the sulphuric radical of which is absorbed by the 
ferrous sulphate, the latter salt becoming ferric sulphate. 
2IIN03 + 3II2S04 + 6FeS04 == 4II20 + 3(Fe23S04) + 2NO. 
The process of oxidation is one frequently employed in experi- 
mental chemistry ; and nitrates, from their richness in oxygen, but 
more especially because always at hand, are the oxidizers usually 
selected for the purpose. In the operation they generally split up in 
one way, namely, into oxide of their basylous radical, nitric oxide 
gas, and available oxygen. Thus hydrogen nitrate (nitric acid) 
yields oxide of hydrogen (water) and the other bodies mentioned, 
as shown in the following equation :— 
4HN03 = 2II20 + 4NO + 302. 
When nitrates, other than nitric acid, are used for the purpose of 
oxidation, a stronger acid, generally sulphuric, is commonly added in 
order that nitric acid may be formed ; the hydrogen nitrate splitting 
up more readily than other nitrates. 
The fine oxides of nitrogen have now been mentioned, namely— 
Nitrous oxide .... N20 
Nitric oxide* . . . .NO 
Nitrous anhydride . . N203 
Nitric peroxide* . . . N02 
Nitric anhydride . . . N205 , 
' N,0 
NA 
n203 
n2o4 
. NA 
or 
* The specific gravities of these gases indicate that NO and NQ2 are 
the correct formula;, and not N2G2 and N2G4. NITRATES. 
287 
Nitrous oxide is a colorless gas not altered by exposure to air; 
nitric oxide is also colorless, but gives red fumes in the air ; nitrous 
anhydride is a red vapor condensible to a blue liquid; nitric peroxide 
is a red vapor condensible to an orange liquid ; nitric anhydride is a 
colorless crystalline solid. The two anhydrides by absorbing water 
yield respectively nitrous acid (IIN02) and nitric acid (11N03). 
Nitrous oxide is also probably an anhydride, the acid of which would 
doubtless have the formula I1NO, while the silver and sodium salts 
certainly have the formulae AgNO and NaN0,3II20 (Divers; Menke). 
The above series of compounds forms a good illustration of the doc- 
trine of multiple proportions (p. 50). 
Third Analytical Reaction.—Direct the blowpipe-flame on 
to charcoal until a spot is red hot; now place on the spot a 
fragment of nitrate; deflagration ensues. 
This reaction does not distinguish nitrates from chlorates. It is 
insufficient for the recognition of very small quantities of either class 
of salts, especially when they are mixed with other substances. 
Gunpowder is an intimate mechanical mixture of 75 parts of nitre, 
15 to 12£ parts of charcoal, and 10 to 12£ parts of sulphur. In burn- 
ing it may be said to give sulphide of potassium (the white smoke), 
(K2S), nitrogen (N), carbonic oxide (CO), and carbonic acid (C02) 
gases, though the decomposition is seldom complete. The sudden 
production of a large quantity of heated gas from a small quantity of 
a cold solid is sufficient to account for all the effects of gunpowder. 
Fourth Analytical Reaction.—To nitric acid or other nitrate 
add solution of “ sulphate of indigo the color is discharged. 
Test-Solution of Indigo. U. S. P. (Sulphindylic or Sulphindigotic 
acid), is made by digesting 1 part of dry, finely powdered indigo in 
12 parts of strong sulphuric acid in a test-tube for an hour, the 
mixture being kept hot by a water-bath ; the blue liquid is then 
poured into 500 parts of sulphuric acid, the whole well shaken, set 
aside, and the clear liquid decanted. Free chlorine also destroys 
the color of this reagent. 
Indigo, U. S. P. (C8II5NO), is a blue coloring-matter deposited 
when infusion of various species of Indigofera is exposed to air and 
slight warmth. Under these circumstances indican, a yellow trans- 
parent amorphous substance, soluble in water, breaks up into indigo, 
which is insoluble and falls as a sediment, and a sort of sugar termed 
indiglucin. The indigo is collected, drained, pressed, and dried. 
By action of deoxidizing agents indigo is converted into soluble 
colorless indigogen, reduced indigo or uihite indigo (CgII6NO); 1 
part of powdered indigo, 2 of green sulphate of iron, 3 of slaked 
lime, and 200 of water, shaken together and set aside in a well- 
closed bottle, give this colorless indigo. A piece of yarn, calico, or 
similar fabric dipped into such a solution, and exposed to air, be- 
comes dyed blue, deposition of insoluble indigo-blue occurring 
within the cells and vessels of the fibre. This operation is readily 
performed on the small scale, and forms a good illustration of the 288 
SALTS OF ACIDULOUS RADICALS. 
characteristic feature of the art of dyeing, namely, the introduction 
of soluble coloring-matter into a fabric by permeation of the walls 
of its cellular and vascular tissue, and the imprisonment of that 
coloring-matter by conversion into a solid and insoluble form (vide 
also p. 137). 
Pure indigo, or indigotin, may be obtained in beautiful needles by 
spreading a paste of indigo and plaster of Paris on a tin plate, and 
when dry placing a lamp underneath, moving the latter from place 
to place as the indigo sublimes and condenses on the surface of the 
plaster. It may also be obtained in crystals by gently boiling finely 
powdered indigo with aniline, filtering while hot, and setting aside; 
these crystals may be washed with alcohol. Hot paraffin may be 
employed instead of aniline. It is possible to obtain indigotin arti- 
ficially •, indeed Baeyer relates that indigo can be made economically 
from benzol, this being first converted into isatine chloride. 
Distinction between Nitric Acid and other Nitrates.—Presence of 
the nitric radical in a solution having been proved by the above re- 
actions, its occurrence as the nitrate of a metal is demonstrated by 
the neutral, or nearly neutral, deportment of the liquid with test- 
paper and the detection of the metal, its occurrence as nitric acid 
by the sourness of the liquor to the taste and the effervescence pro- 
duced on the addition of a carbonate. 
Antidote.—In cases of poisoning by strong nitric acid, solution of 
carbonate of sodium (common washing soda) or a mixture of mag- 
nesia and water may be administered as antidotes. 
QUESTIONS AND EXERCISES. 
444. Trace the origin of nitrates. 
445. In what does cubic nitre differ, chemically, from prismatic 
nitre ? 
446. Describe a process by which nitrate of potassium may be 
obtained artificially. 
447. State the difference between nitrate of potassium, nitre, salt- 
petre, and sal prunella. 
448. What group of elements is characteristic of all nitrates? and 
what claim has this group to the title of radical? 
449. Mention the usual theory regarding the manner in which 
atoms are arranged with reference to each other in such salts as 
nitrate of potassium. 
450. How is Nitric Acid prepared? 
451. Give the properties of nitric acid. 
452. What reactions occur when strong nitric and hydrochloric 
acids are mixed ? 
453. How is nitric oxide prepared ? 
454. Enumerate and explain the tests for nitrates. 
455. Into what substances does nitric acid usually split when em- 
ployed as an oxidizing agent? 
456. How is nitrous oxide prepared? 
457. Enumerate the five oxides of nitrogen. CHLORATES. 
289 
458. What is the nature of gunpowder? 
459. Write a few sentences on the chemistry of indigo, one of the 
tests for nitric acid. 
460. How is nitric acid distinguished from other nitrates? 
461. What quantity of cubic nitre will be required to produce ten 
carboys of official nitric acid, each containing 114 pounds?—Ann. 
1076§ pounds. 
CHLORIC ACID AND OTHER CHLORATES. 
Formula of Chloric Acid HCIO,. Molecular weight 84.4. 
Chlorates are made from hypochlorites. 
Hypochlorous Acid (HCIO) and other Hypochlorites. 
Place a few grains of red oxide of mercury in a test-tube, 
half fill the tube with chlorine-water, and well shake the mix- 
ture ; the resulting liquid is a solution of hypochlorous acid, 
mercuric oxychloride remaining undissolved : 
2HgO + 2C12 + II20 = HCIO + Hg2OCl2. 
By the metathesis (double decomposition) of hypochlorous 
acid and oxides or hydrates, other pure hypochlorites are 
formed :— 
HCIO + NallO - NaCIO + II20. 
The direct action of chlorine on metallic hydrates and some 
carbonates is supposed to give a mixture of chloride and hypo- 
chlorite, as described in connection with the synthetical reac- 
tions of Calcium (p. Ill, Calx Chlorata, U. S. P.) 
Cl* + 2NaHO = NaCl,NaCIO + H,0; 
2C12 + 2CaH202 = CaCl2,Ca2C10 + 2H20. 
The condition of chlorides in these bodies is not satisfactorily 
made out; so that their constitution is not definitely deter- 
mined. The action of acids on them results in the evolution 
of chlorine ; hence the great value of the calcium compound 
(chlorinated lime, or chloride of lime) in bleaching opera- 
tions :— 
CaCl2,Ca2C10 + 2H2S04 = 2C12 + 2CaS04 + 2H*0. 
The solubility of hypochlorites in water, their peculiar odor, 
greatly intensified on the addition of acid, and their bleaching 
powers (see the above Calcium reaction) are the characters on 
which to rely in searching for hypochlorites. 
Chlorates. 
The group of elementary atoms represented by the formula CIO, 
is that characteristic of chloric acid and all other chlorates; hence it 290 
is expedient to regard it as being an acidulous radical, which may be 
termed the chloric radical. Like the nitric radical, it has not been 
isolated. Chloric anhydride (C1205), unlike nitric anhydride, has not 
yet been obtained in the free condition. 
Chlorates are artificial salts. They are formed by simply boiling 
aqueous solution of the common bleaching salts (chlorinated lime, 
chlorinated soda, chlorinated potash). Heat thus converts 
3(NaCl, NaCIO) 
Chlorinated soda. 
into 
NaC103 
Chlorate of 
sodium. 
and 
5NaCl 
Chloride of 
sodium. 
5KC1 
Chloride of 
potassium. 
3(KC1, KC10) 
Chlorinated 
potash. 
into 
KC103 
Chloratp 
of potassium. 
and 
3(CaCl2, Ca2C10) 
Chlorinated 
lime. 
into 
Ca2C103 
Chlorate of 
calcium. 
and 
5CaCl2 
Chloride of 
calcium. 
One chlorate may also be made from another by double decomposi- 
tion. In making chlorates economically the chlorinated salt is, of 
course, at once converted into chlorate. 
Chlorate of Potassium. 
Thus Chlorate of Potassium (Pofassii Chloras, U. S. P.) is 
commercially made by saturating with chlorine gas a moistened 
mixture of three parts of chloride of potassium and ten of 
slaked lime, and well boiling the product. Chlorinated lime is 
first formed; this, on continued boiling with water, splits up 
into chloride of calcium and chlorate of calcium, and the latter, 
reacting on the chloride of potassium, yields chloride of calcium 
and chlorate of potassium. 
6(Ca2HO) + 6C12 = 3(CaCl2,Ca2C10) + 6H20; 
3(CaCl2,Ca2C10) = Ca2C103 + 5CaCl2; 
Ca2C10, + 2KC1 = CaCl2 + 2KC103. 
This operation may be conducted on a small scale by rubbing 
together in a mortar the above proportions of ingredients in 
ounces or half ounces, adding enough water to make the whole 
assume the character of damp lumps, placing the porous mass 
in a funnel (loosely plugged with stones or pieces of glass), 
and passing chlorine gas (p. 27) through the mass by attaching 
the tube delivering the gas to the neck of the funnel. When 
the whole mass has become of a slight pink tint (due to a trace 
of permanganate), it should be turned into a dish, well boiled 
with water, filtered, the filtrate evaporated if necessary, and 
set aside; the chlorate of potassium crystallizes out in color- 
less rhomboidal plates, chloride of calcium remaining in the 
mother-liquor. CHLORATES. 
291 
In the official process carbonate of potassium, instead of chloride, 
is used; but otherwise it is similar to the method just described. 
Chlorinated potash and chlorinated lime are first formed :— 
K2C03 + Ca2HO + Cl2 = KC1,KC10 + CaC03 + II20, 
6(Ca2I10) + 6C12 = 3(CaCl2,Ca2C10) + fill20; 
these, on boiling with water, split up into chlorates and chlorides— 
3(KC1,KC10) = KC103 + 5KC1, 
3(CaClj,Ca2C10) = Ca2C103 + 5CaC!2; 
the whole of the chloride of potassium and chlorate of calcium finally 
yielding chlorate of potassium and chloride of calcium— 
2KC1 + Ca2C103 = CaCl2 + 2KC103. 
Neglecting intermediate decomposition, the reactions may be repre- 
sented by the following equation : 
6C12 + K2C03 + 6CaH202 = 2KC10. + CaCO, 
Chlorine. 
Carbonate of 
potassium. 
z 
Hydrate of 
calcium. 
3 
Chlorate of 
potassium. 
, 3 
Carliouate of 
calcium. 
+ 5CaCl2 + 6H20 
Chloride of 
calcium. 
Water. 
Chlorate of Sodium (Sodii Chloras, U.S.P.), NaC103, is similarly 
prepared. 
Chlorate of potassium is soluble in water to the extent of 6 or 7 
parts in 100 at common temperatures. It must on no account be 
rubbed with sulphur in a mortar or otherwise, friction of such a 
mixture resulting in violent explosion. 
Chlorate of potassium, when heated, yields chloride of potassium 
and oxygen, and is the salt commonly employed in the preparation 
of the gas for experimental purposes. But if the action be arrested 
when one-third of the oxygen has escaped, the residual salt is found 
to contain perchlorate of potassium (KC104) :— 
2KC103 = KCI04 + KC1 + 02. 
Perchloric Acid (IIC104).—Crude perchlorate of potassium, ob- 
tained as just indicated, is boiled (in a fume-cupboard) with hydro- 
chloric acid to decompose any chlorate that may be remaining, and 
then separated from chloride by washing and crystallization, chloride 
being far more soluble in water than the perchlorate. Perchloric 
acid is then obtained by distilling the perchlorate of potassium with 
sulphuric acid ; it is quite stable, and is occasionally administered in 
medicine. 
Chloric Acid (IICIO,) may be isolated, but is unstable, quickly 
decomposing into chlorine, oxygen, and perchloric acid; some other 
chlorate (e. g., KC103) must therefore be used in studying the reac- 
tions of the chloric radical. 292 
SALTS OF ACIDULOUS RADICALS. 
Table of the Chlorine Acids. 
Hydrochloric acid .... HOI. 
Hypochlorous acid .... IICIO. 
Chlorous acid HC102. 
Chloric acid ...... IIC103. 
Perchloric acid ..... IIC104. 
The chloric radical is univalent (jC103). The acidulous radicals 
of the other chlorine acids are also univalent, as indicated in the 
foregoing formulae. 
• Analytical Reactions ( Tests). 
First Analytical Reaction.—To solution of a chlorate (e. g., 
chlorate of potassium) add solution of nitrate of silver ; no pre- 
cipitate falls, showing that the chlorine must be performing 
different, functions from those it possesses in chlorides. Evap- 
orate the solution to dryness, and place the residue in a small 
dry test-tube, or at once drop a fragment of a chlorate into a 
test-tube, and heat strongly ; oxygen is evolved, and may be 
recognized by its power of re-inflaming an incandescent match 
inserted in the tube. Boil the residue with water, and again 
add solution of nitrate of silver; a white precipitate falls, hav- 
ing all the characters of chloride of silver, as described under 
Hydrochloric Acid. 
This is a trustworthy test, and, even omitting the recognition of 
the oxygen, may be applied in the detection of small quantities of 
chlorates. 
Second Analytical Reaction.—To a fragment of a chlorate 
add two or three drops of strong sulphuric acid ; an explosive 
gas (CIA) is evolved, somewhat resembling chlorine in odor, 
but possessing a deeper color than that element. 
3KC103 + II2S04 = CIA + KCIO* + K2S04 + HA 
Warm the upper part of the test-tube to 150° or 200° F., or 
introduce a hot wire ; a sharp explosion ensues, due to decom- 
position of the gas, peroxide of chlorine, into its elements. 
Third Analytical Reaction.—Heat a small fragment of a 
chlorate with hydrochloric acid: a yellowish-green explosive 
gas termed euchlorine is evolved. Its color is deeper than that 
of chlorine, hence the name (from eu, eu, well, and %ku}p6q, 
chloros, green). In odor it resembles chlorine, and is probably 
a mixture of that element with one of the oxides of chlorine. 
Fourth Analytical Reaction.—Direct the blowpipe-flame on 
to charcoal until a spot is red hot, and then place on the spot 
a fragment of a chlorate; deflagration ensues as with nitrates. IODATES. 
293 
Bromates. 
Bromates are salts closely resembling chlorates and iodates. The 
formula of Bromic Acid is IIBr03. 
Iodates. 
Iodic Acid (IIIO:!).—Iodine is boiled in a flask with five times its 
weight of the strongest nitric acid (sp. gr. 1.5), in a fume-cupboard, 
until all action ceases. On cooling, iodic acid separates in small 
pyramidal crystals. These are removed, the residual liquid evapor- 
ated to dryness to remove excess of nitric acid, the residue and the 
first crop dissolved in a small quantity of boiling water, and the 
solution set aside to crystallize. 
Iodate of Potassium (KIOa).—Powder together equal weights of 
iodine and chlorate of potassium ; to the mixture add twice its weight 
of water and about one-eighth of its weight of nitric acid ; warm the 
whole until iodine disappears, and evaporate quite to dryness over a 
water-bath. The residue dissolved in water forms “ Solution of 
Iodate of Potash,” B. P. It contains a little nitrate of potassium. 
In this reaction the small quantity of nitric acid furnishes corre- 
sponding amounts of nitrate of potassium and chloric acid. The 
chloric acid with iodine gives iodic acid and chlorine, thus:— 
2IICIO3 + I2 = 2III03 + Cl2. 
The iodic acid and some chlorate of potassium then yield chloric acid 
and iodate of potassium— 
IIIO3 + KCIO3 = IICIO3 + KI03; 
and the two reactions alternate until the whole of the iodine has dis- 
placed the whole of the chlorine. 
Iodate of potassium and sulphurous acid decompose each other 
with elimination of iodine (or with formation of a blue color, if starch 
be present.) Sulphurous acid occurring as an impurity in acetic and 
other acids may thus be detected. 
2KI03 + 5H2S03 = I2 + 3II2S04 + 2KIIS04 + II20. 
If iodic acid solution be mixed with mucilage of starch, and solu- 
tion of sulphuretted hydrogen be added, a blue zone is formed at the 
junction of the liquids. 
Ferric iodate, or rather Oxyiodate (Fe204I03,8II20), is precipi- 
tated on adding solution of ferric chloride to solution of iodate of 
potassium. 
462. How may hypochlorous acid be formed? 
463. What are the relations of hypochlorous acid to common 
bleaching-powder ? 
464. By what reaction is chlorine eliminated from hypochlorites ? 
465. State the general reaction by which chlorates are formed. 
466. Give details of the preparation of chlorate of potassium. 
QUESTIONS AND EXERCISES. SALTS OF ACIDULOUS RADICALS. 
467. Mention the properties of chlorate of potassium. 
468. What decompositions occur when chlorate of potassium is 
heated ? 
469. Find the molecular weight of chlorate of potassium. 
470. What weight of oxygen is yielded w hen 1 oz. of chlorate of 
potassium is completely decomposed, and how much chloride of 
potassium remains? 
471. One hundred cubic inches of oxygen, at 60° F. and barometer 
at 30 inches, weighing 34.203 grains, and 1 gallon containing 
cubic inches, what weight of chlorate of potassium will be required 
to yield 10 gallons of the gas? Ans. 5| ounces. 
472. How many cubic inches of oxygen are producible from 1 oz. 
of chlorate of potassium? 
473. Calculate the weight of chlorate of potassium theoretically 
obtainable from 100 parts of chloride. 
474. IIowt is perchloric acid prepared? 
475. Enumerate the chlorine acids. 
476. IIowr may the presence of chlorides in chlorates be demon- 
strated ? 
477. Mention the tests for chlorates. 
478. Give the formula of peroxide of chlorine. 
479. What is euchlorine? 
480. How may iodic acid be made ? 
481. Describe the preparation of iodate of potassium. 
ACETIC ACID AND OTHER ACETATES. 
Formula of Acetic Acid HC2Hs02, or IIA. Molecular weight 60. 
Source.—Acetic acid is said to occur naturally in certain plant 
juices and animal fluids in minute proportions, but otherwise is an 
artificial product. Much is furnished by the destructive distillation 
of wood, hence the term pyroligneous acid for the crude product, a 
hybrid word from m>p, pur, fire, and lignum, wood. This impure 
product, neutralized by carbonate of sodium, the whole evaporated, 
and the residue gently heated to drive off- the volatile tarry matters, 
gives acetate of sodium, which after recrystallization furnishes by 
distillation with oil of vitriol and water acetic acid in a fair state of 
purity. In Germany and France large quantities of acetic acid are 
made by the spontaneous oxidation of the alcohol in inferior wines, 
in the presence, according to Pasteur, of a plant-ferment termed 
Mycoderma aceti (the Bacterium mycodermi of Cohn); hence the 
white- and red-wine vinegar (vinegar, from the French vin, wine, and 
aigre, sour). Indeed this bacterium may be propagated, and the 
artificial manufacture of vinegar from alcohol and water be carried 
out, by its acid, on a large scale. In England also the domestic 
form of acetic acid (browm vinegar) has a similar origin : infusion of 
malt and unmalted grain is fermented, and the resulting oxidation 
of its sugar, instead of being arrested when the product is an alco- 
holic liquid, a sort of beer, is allowed to go on to the next stage, ACETATES. 
295 
acetic acid; it usually contains from 3 to 6 per cent, of real acetic 
acid (IIC2H,02). 
Vinegars.—Ordinary brown vinegar contains about 51 per cent, 
of acid. The so-called Vinegar of Cantharides (Acetum Cantharidis, 
B. P .) is a solution of the active principle of cantharides in very 
strong acetic acid, not in vinegar. The Vinegar of Squill (Acetum 
Scillce, U. S. P.) is also a solution of the active principle of squill in 
dilute acetic acid, not in true vinegar. The same may be said of 
Acetum Lobelias, U. S. P., and Acetum Sanguinarias, U. S. P. (Vin- 
egar of Blood-root). The Acetum Opii, U. S. P., or Black Drop of 
America, is made from nutmeg, saffron, and sugar, as well as Opium 
and Diluted Acetic Acid. 
The Acetic Radical.—The group of elements represented by the 
formula C2II302 is that characteristic of acetic acid and other ace- 
tates, and may, for convenience of study, be assumed to be an acid- 
ulous univalent radical. It has not been isolated, unless indeed a 
compound of similar composition, resulting from the action of perox- 
ide of barium on acetic anhydride, is the radical in question. 
Acetyl.—The characteristic grouping in acetates, C.,ll302, is fre- 
quently considered to contain, rather than to be, a radical—C2fl30, 
termed acetyl. Acetates yield a body having the composition 
C, 30C1, which is regarded as chloride of acetyl; from this may be 
obtained acetic anhydride (C4ll60.s), which by absorbing water be- 
comes acetic acid. 
0,11,0) 
Cl | 
C,H,0 { Q 
C2II30 }u 
C2II30}o 
<w»0 
w}u 
Chloride of 
acetyl. 
Acetic 
anhydride. 
Acetic acid. 
Metallic 
acetates. 
The relation of acetic acid to alcohol will be evident from the fol- 
lowing equation representing empirically the formation of the acid :— 
CJIgO + 0, = C2II402 + II20. 
Alcohol. Acetic acid. 
Acetates in aqueous solution are liable to decomposition. In solu- 
tion of acetate of morphine a myceloid growth occasionally forms, 
acetic acid disappears, and morphine is deposited. Solution of ace- 
tate of ammonium is liable to a similar change, gradually becoming 
alkaline. 
Synthetical Reaction. 
Acetic Acid. 
Synthetical Reaction.—To a few grains of acetate of sodium 
in a test-tube add a little water and some sulphuric acid, and 
heat the mixture; acetic acid is evolved, and may be con- 
densed by a bent tube adapted to the test-tube by a cork in the 
usual way. 
Acetic Acid.—This is the process by which acetate of sodium or 
calcium (the neutralized products of the distillation of wood) is made 
to yield acetic acid on the large scale. As with nitric and hydro- 296 
SALTS OF ACIDULOUS RADICALS. 
chloric acids, the loose term “acetic acid” is that usually applied to 
aqueous solutions of acetic acid. The Acidum Aceticum, U. S. P., 
contains 36 per cent, of real acid, that is, of HC2H30,; for it con- 
tains only 30.6 per cent, of acetic anhydride (C4I1603)—-still occa- 
sionally though somewhat obscurely termed anhydrous acetic acid. 
Its specific gravity is 1.048. Acidum Aceticum Dilutum, U. S. P., 
contains 6 per cent, of IIC2H302. Sp. gr. 1.0083. Glacial acetic 
acid (IIC2II302) contains no water. It solidifies to a crystalline mass 
at and below 15° C. (59° F.), hence the appellation glacial (from gla- 
des, ice). Sp. gr. from 1.056 to 1.058. Good commercial glacial 
acetic acid (Acidum Aceticum Glaciale, U. S. P.) does not contain 
more than 1 per cent, of water, corresponding to 84.15 per cent, of 
acetic anhydride. Although water is lighter than this acetic acid, 
yet the addition of water at first renders the acid heavier; evidently 
therefore condensation, or contraction in bulk, occurs on mixing the 
liquids: after 10 per cent, has been added, the addition of more 
water produces the usual effect of dilution of a heavy liquid by a 
lighter, namely, reduction of relative weight. This matter will be 
better understood after the subject of specific gravity has been 
studied. 
The following equation is expressive of the foregoing reaction:— 
Acetate of 
sodium. 
NaC2H302 + H2S04 = HC2H302 + NaIIS04 
Sulphuric 
acid. 
Acetic acid. 
Acid sulphate 
of sodium. 
or, assuming the existence of acetyl (C21I30) in acetic acid, and a 
corresponding radical sulphuryl (S02) in sulphuric acid— 
C2H:jO ) Q S02 } Q _ C2H30 ) Q S02) Q . 
NajU 1 H2 j 2 — H|U Nail j ’ 
or, thirdly, on the assumption that salts contain the oxide of a basy- 
lous radical united with the anhydride of an acid (the old view under 
which such names as acetate of soda were formed)— 
Na20,C4II603 + 2II20,S08 - Na,0,H20,2S03 + H20,C4H603- 
Note on the Constitution of Salts. 
Which of these three equations, or, more broadly, which of the 
tliree views of the constitution of salts illustrated by the equations, 
is correct, it is impossible to say. Whether it is C2H.,02, C2II30, 
or C4II603, which migrates from one acetic compound to another, 
whether it is S04, S02, or S03, which migrates from one sulphuric 
compound to another, and so on with other acidulous groupings, 
cannot at present be determined. There are strong objections to 
each view; and possibly neither is right. Either the given radicals 
cannot be isolated, or application of the forces of heat, light, and 
electricity do not confirm views arrived at by the results of opera- 
tions with the chemical force; or a salt comes to be regarded as 
having so large a number of constituent parts that the view, how- 
ever true, breaks down in practice from the sheer inability of the 
mind to grasp the complicated analogies involved. Yet for the pur- 
poses of description, study, and conversation some system must be ACETATES. 
297 
adopted. Let the first, then, be generally taken, over-reliance on it 
being checked by the use of general instead of special names for the 
hypothetical radicals, and other systems be employed in certain cases. 
(See also p. 283.) 
First Analytical Reaction.—To an acetate add sulphuric 
acid and heat the mixture; acetic acid, recognized by its odor, 
is evolved. 
Note 1.—Iodine, sulphurous acid, and other substances of power- 
ful odor, mask that of acetic acid; they must be removed, therefore, 
usually by precipitation or oxidation, before applying this test. 
Note 2.—It will be noticed that this reaction is identical with the 
previous one; it has synthetical or analytical interest, according to 
the object and method of its performance. 
Second Analytical Reaction.—Repeat the above action, a few 
drops of spirit of wine being first added to the acetate; acetic 
ether (acetate of ethyl, C2H5C2H302), also of characteristic 
odor, is evolved. 
The basylous radical ethyl (C.2II5) will be referred to subsequently. 
Third Analytical Reaction.—Heat a fragment of'a dry ace- 
tate in a test-tube, and again notice the odor of the gaseous 
products of the decomposition ; among them is acetone (C3H60), 
the smell of which is characteristic. Carbonate of the metal 
remains in the test-tube. 
Fourth Analytical Reaction.—To a solution of an acetate 
made neutral by the addition of acid or alkali, as the case may 
be, add a few drops of neutral solution of perchloride of iron ; 
a deep-red liquid results, owing to the formation of ferric 
acetate (Fe26C2H302). Boil; a precipitate of oxyacetate of 
iron occurs, leaving the liquid colorless. Strong acids also 
decompose ferric acetate. 
Analytical Note.—It will be noticed that the formation of cha- 
racteristic precipitates, the usual method of removing radicals from 
solution for recognition, is not carried out in the qualitative analysis 
of acetates. This is because all acetates are soluble. Acetate of 
silver (AgC2H302) and mercurous acetate (IIgC2II302) are only spar- 
ingly soluble in cold water, but the fact can seldom be utilized in 
analysis. Hence peculiarities of color and odor, the next best cha- 
racters on wThich to rely, are adopted as means by which acetates 
may be detected. Acetates, like other organic compounds, char 
when heated to a high temperature. 
Note on Anhydrides.—Up to this point the student has regarded 
an anhydride as a body derived from an acid by removal of the 
whole of the hydrogen of the acid, together with as much of its oxy- 
Analytical Reactions ( Tests'). 298 
SALTS OF ACIDULOUS RADICALS. 
gen as with the hydrogen forms water. The definition will scarcely 
apply to acetic anhydride, and must therefore be somewhat qualified. 
An anhydride is derived from an acid, the acid having lost the whole 
of its basylous hydrogen and so much oxygen as is necessary to form 
water with that hydrogen. Anhydrides are obtained by heating 
acids, and by other methods. 
482. What is the formula of acetic acid ? 
483. State the relation of acetic acid to other acetates. 
484. What is the molecular weight of acetic acid ? 
485. Name the sources of acetic acid. 
486. What is pyroligneous acid? 
487. From what compound is the acetic acid of foreign and Eng- 
lish vinegar immediately derived ? 
488. How much real acid is contained in official vinegar ? 
489. What is the nature of the “Vinegars” of Pharmacy? 
490. llow may acetic acid be obtained from acetate of sodium? 
491. How much real acid is contained in the official acetic acid? 
492. Mention the strength of commercial glacial acetic acid. 
493. Give three or more views of the constitution of acetates, illus- 
trating each by formulae. 
494. Enumerate the tests for acetates. 
QUESTIONS AND EXERCISES. 
HYDROSULPHURIC ACID AND OTHER SULPHIDES. 
Formula of Hydrosulphuric Acid I12S. Molecular weight 34. 
Source and Varieties of Sulphur.—The acidulous radical of hydro- 
sulphuric acid, sulphydric acid, or sulphuretted hydrogen, and other 
sulphides, is the element sulphur (S). It occurs in nature in combi- 
nation with metals, as already stated in describing the ores of some 
of the metals, and also in the free state. Most of the sulphur used 
in medicine is imported from Sicily, where it occurs chiefly associated 
with blue clay. It is purified by fusion, sublimation, or distillation. 
Melted and poured into moulds, it constitutes a crystalline mass 
termed roll sidphur. If distilled and the vapor carried into large 
chambers, so that it may be rapidly condensed, the crystals are so 
minute as to give the sulphur a pulverulent character; this is sub- 
limed sidphur (Sulphur Sublimatum, U. S. P.) or flowers of sulphur: 
the same washed with dilute ammonia, to remove traces of sulphuric 
acid, or, possibly, arsenious sulphide, constitutes Sulphur Lotum, 
U. S. P. 
The third common form, milk of sulphur, will be noticed subse- 
quently. Sulphur also occurs in nature in combination as a constit- 
uent of animal and vegetable tissues, as sulphurous acid gas (S02) 
in volcanic vapors, and as sulphuretted hydrogen in some waters, as 
those of Harrogate. 
Plastic sulphur is one of the allotropic varieties of the element, SULPHIDES. 
obtained on heating sulphur considerably beyond its melting-point 
and pouring into cold water. 
Quant [valence.—Sulphur is sexivalent, as seen in sulphuric anhy- 
dride (S03), a substance which will be noticed under sulphuric acid. 
It also occasionally exhibits quadrivalent (S02) and still oftener biv- 
alent affinities (II2S). 
Molecular Weight.—At very high temperatures sulphur follows 
the rule that, under similar conditions of heat and pressure, atomic 
weights (in grammes, grains, etc.) of volatile elements occupy equal 
volumes of vapor; its formula therefore is S2, and molecular weight 
64. At lower temperatures the volume wreighs three times as much 
as it should do if following usual laws, and then the molecule would 
appear to contain six atoms (S6). 
Acid Salts.—Sulphur (S//) being the first acidulous radical of 
bivalent activity met with in these sections on acids, it is desirable 
here to draw attention to a new class of salts to which such a rad- 
ical will generally give rise. These are acid salts, which are inter- 
mediate betwreen normal salts and acids. Univalent radicals with an 
atom of hydrogen give an acid, and with an atom of other basylous 
radicals an ordinary or normal salt. But bivalent radicals, from the 
fact that they give with two atoms of hydrogen an acid, and with 
two atoms of univalent metals a normal salt, may obviously give 
intermediate bodies containing one atom of hydrogen and one 
atom of metal: these are appropriately termed acid salts: they are 
neither normal acids nor normal salts, but acid salts. (Examples: 
KIICO3, NaHS04, K 11C,II406, Na.IIPO,, CuHAs03, CaII42P04.) 
Whether or not these salts give an acid reaction with blue litmus- 
paper depends on the strength of the respective radicals. Usually 
they do redden the test-paper, but sometimes not; thus the acid sul- 
phide or sulphydrate of potassium (KIIS), of sodium (NaHS), or 
ammonium (Am II8) has alkaline properties.* 
The chemical analogy between sulphur and oxygen, already once 
alluded to (p. 173), is further illustrated by the compounds just 
mentioned. Sulphur is also closely related to the rarer element 
Selenium. Thus we have Se02 as wrell as S02, II2Se03 (selenious 
acid) as well as H2S03 (sulphurous acid), II2Se04 (selenic acid) as 
well as II2S04 (sulphuric acid). The rare element Tellurium also 
seems to have similar analogies. The four hydrogen compounds of 
the group have the formulae H20, II2S, II2Se, HaTe. 
Synthetical Reactions. 
First Synthetical Reaction : The preparation of sulphuretted 
Sulphuretted Hydrogen. 
* Some chemists regard these sulphydrates as compounds of basylous 
radicals with IIS, a univalent grouping termed hydrosulphyl (persul- 
phide of hydrogen, H2S2), just as hydrates are similarly viewed as 
compounds of the univalent radical hydroxyl (HO) (peroxide of hy- 
drogen, H202)—II2S becoming ITHS or IIHs (hvdrosulphylide of hy- 
drogen), and H20 becoming IIHO or HHo (hydroxylide of hydrogen). 300 
SALTS OF ACIDULOUS RADICALS. 
hydrogen.—This operation was described on page 95, and prob- 
ably has already been studied by the reader. 
Precipitated Sulphur. 
Second Synthetical Reaction.—Prepare the variety of the 
radical of sulphides known as Precipitated Sulphur (Sulphur 
Prsecipitatum, U. S. P.), or milk of sulphur, by boiling a few 
grains of flowers of sulphur (100 parts) with slaked lime (66 
parts) and some water (500 parts) in a test-tube (larger 
quantities in an evaporating-basin), filtering, and (reserving a 
small portion of the filtrate) adding dilute hydrochloric acid 
until the well-stirred milklike liquid has still a faint alkaline 
reaction on test-paper; sulphur is precipitated, and may be 
collected on a filter, washed and dried (at about 120°). Excess 
of acid must be avoided, or some hydrosulphyl, the liquid per- 
sulphide of hydrogen (H2S2), will be formed, probably causing 
the particles of sulphur to aggregate to a gummy mass. 
This is the process of the Pharmacopoeias. Polysulphide of cal- 
cium and hyposulphite of calcium are formed :— 
3CaH20, + 6S2 = 2CaS5 + CaS,03 + 3H20 
Hydrate of 
calcium. 
Sulphur. 
Polysulphide 
of calcium. 
Hyposulphite 
of calcium. 
Water. 
On adding the acid, both salts are decomposed and, after an inter- 
mediate reaction, sulphur separates :— 
Polysulphide 
of calcium. 
2CaS5 + CaS2Og + 6IIC1 = 3CaCl2 + 3H20 + 6S2 
Hyposulphite 
of calcium. 
Hydrochloric 
acid. 
Chloride of 
calcium. 
Water. 
Sulphur. 
The polysulphide of calcium yields sulphuretted hydrogen and 
milk-white sulphur on the addition of acid. The hyposulphite of 
calcium then yields sulphurous acid gas as well as a yellowish sul- 
phur. The gases react and give sulphur and water, very little sul- 
phuretted hydrogen escaping. A little pentathionic acid (see Index) 
is also said to be formed. 
4II2S + 2S02 = 3S2 + 4H20. 
Calcareous Precipitated Sulphur: The old 11 Milk of Sul- 
phur.”—To a sulphur solution prepared as before (or to the 
reserved portion) add a little dilute sulphuric acid; the pre- 
cipitate is in this case largely mixed with sulphate of cal- 
cium :—• 
Polysulphide 
of calcium. 
2CaS5 + CaS2Oa + 3H2S04 + 3H20 = 3(CaS04,2H20) 
Hyposulphite 
of calcium. 
Sulphuric 
acid. 
Water. 
Sulphate of 
calcium. 
+ 6S2 
Sulphur. SULPHIDES. 
301 
Place a little of each of these specimens of precipitated sul- 
phur with a drop of the supernatant liquid on a strip of glass, 
cover each spot with a piece of thin glass, and examine the 
precipitates under a microscope ; the pure sulphur will be found 
to consist of minute grains or globules, the calcareous to con- 
tain comparatively large crystals (sulphate of calcium). 
Note.—A large proportion of the precipitated sulphur met with 
in trade in England still is thus mixed with sulphate of calcium, 
most of such specimens containing two-thirds of their weight of 
that substance. Many purchasers, indeed, are so accustomed to the 
satiny appearance of the mixed article as to regard the real sulphur 
with suspicion, sometimes refusing to purchase it. The mixed arti- 
cle is, certainly, more easily mixable with aqueous liquids; but it 
has long been discarded from the Pharmacopoeias of Great Britain, 
and, on the whole, is scarcely worthy of a prominent place in the 
pharmacy of 1883. 
Many English pharmacists have ceased to sell any sulphur which 
yields a white ash (the anhydrous sulphate) when a little is burnt 
off on the end of a table-knife or spatula. (No more damage is 
done to the steel than a rub on a knife-board will remove.) 
To ascertain exactly the amount of sulphate of calcium in a speci- 
men of calcareous precipitated sulphur, place a weighed quantity in 
a tared crucible and heat till no more vapors are evolved. The 
weight of the residual anhydrous sulphate of calcium (CaS04 = 136), 
with one-fourth thereof added, is the amount of crystalline sulphate 
of calcium (CaS04,2II20 = 172) present in the original quantity of 
calcareous sulphur. 
To a sulphide add a few drops of hydrochloric acid ; sul- 
phuretted hydrogen will probably be evolved, well known by 
its smell. If the sulphide is not acted upon by the acid, or if 
free sulphur he under examination, mix a minute portion with 
a fragment of solid caustic potash or soda and fuse on a silver 
coin or spoon. When cold, place a drop of dilute hydrochloric 
acid on the spot; sulphuretted hydrogen is evolved, and a black 
stain, due to sulphide of silver (Ag2S), left on the coin. 
Other sulphur reactions may be adopted as tests, but the above 
are sufficient for all ordinary purposes. The most convenient re- 
agent for detecting a sulphide in solution of ammonia is atnmonio- 
sulphate of copper, which gives a black precipitate of sulphide of 
copper if a sulphide be present. 
The Iodide of Sulphur (S2I2) has been mentioned under u Iodine.” 
A chloride (S2C12) and bromide (S2Br2) may also be formed from 
their elements. A mixture of sulphur and chloride of sulphur is 
sometimes met with under the name of hypochloride of sulphur. 
Analytical Reactions ( Tests). 302 
SALTS OF ACIDULOUS RADICALS. 
495. In what form does sulphur occur in nature ? 
496. State the modes of preparation of the three chief commercial 
varieties of sulphur. 
497. To what extent does the atom of sulphur vary in quantiva- 
lence ? 
498. State the relations of acid salts to acids and to normal salts. 
499. Define sulphides and sulphydrates. 
500. Describe the preparation of sulphuretted hydrogen. 
501. What are the characters of pure precipitated sulphur? 
502. Give equations explanatory of the reactions which occur in 
precipitating sulphur according to the official process. 
503. Describe the microscopic test for calcareous precipitated 
sulphur. 
504. Mention a ready physical method of detecting sulphate of 
calcium in precipitated sulphur. 
505. Mention the tests for sulphides, and the character by which 
sulphuretted hydrogen is distinguished from other sulphides. 
506. How are sulphides insoluble in acids tested for sulphur? 
507. Give a method for the detection of a trace of sulphur in solu- 
tion of ammonia. 
QUESTIONS AND EXERCISES. 
SULPHUROUS ACID AND OTHER SULPHITES. 
Formula of Sulphurous Acid II2S03. Formula of sulphurous acid pas 
or sulphurous anhydride, commonly termed sulphurous acid, S0.2. 
Molecular weight of sulphurous acid 82; of the anhydride 64. 
When sulphur is burned in the air it combines with oxygen and 
forms sulphurous acid gas (S02), more correctly termed sulphurous 
anhydride, or commonly, but erroneously, sulphurous acid. It is a 
pungent, colorless gas, readily liquefied on being passed through a 
tube externally cooled by a freezing-mixture composed of two parts 
of well-powdered ice (or, better, snow) with one part of common 
salt. If sulphurous acid gas becomes moist or is passed into water, 
heat is evolved and true sulphurous acid (H2S03) formed. The 
latter body may be obtained in crystals; but it is very unstable, 
and hence the properties of the sulphurous radical must be studied 
under the form of some other sulphite; sulphite of calcium (CaS03) 
or sulphite of sodium (Na2S03) may be used for the purpose. 
Quantivalence.—The radical of the sulphite is bivalent (SO.//), 
and hence forms acid sulphites, such as acid sulphite of potassium 
(KHS03) and normal sulphites, such as sulphite of sodium (Na2S03). 
Note on Nomenclature.—The sulphites are so named from the 
usual rule, that salts corresponding with acids whose names end in 
ous have a name ending in ite. They are generally made by pass- 
ing sulphurous acid gas over moist oxides or carbonates; in the 
latter case carbonic acid gas escapes. 
Synthetical Reaction.—To a few drops of sulphuric acid in a 
test-tube add a piece of charcoal and apply heat; sulphurous SULPHITES. 
303 
acid gas is evolved, and may be conveyed by a bent tube into 
a small quantity of cold water in another test-tube. Larger 
quantities may be made in a Florence flask. The product is 
the Acidum Sulphurosum, U. S. P. It contains about 4.5 per 
cent, of sulphurous acid (FI2S03) or about 3.5 per cent, of the 
gas (S02). The process is also that described in the Pharma- 
copoeia, except that the gas is purified by passing through a 
small wash-bottle before final collection. Specific gravity 1.022 
to 1.023. 
4H,S04 -f C, = 2 CO, + 4H,0 + 4S02 
Sulphuric 
acid. 
Carbon 
(charcoal). 
Carbonic 
acid gas. 
Water. 
Sulphurous 
acid gas. 
Sulphurous acid gas may also be made by boiling copper, 
mercury, or iron with sulphuric acid, sulphate of the metals 
being formed. Also by boiling sulphur with sulphuric acid. 
so, + h2o = h2so3 
Sulphurous 
acid gas. 
Water. 
Sulphurous 
acid. 
If in this process the water were replaced by solutions of or solid 
metallic oxides or carbonates, sulphites of the various metals would 
be formed. The formula of sulphite of potassium (Potassii Sulphis, 
U. S. P.) is K2S03,2H20; of sulphite of sodium (Sodii Sulphis, 
U. S. P.), Na2S03,71I20 : of the bisulphite or acid sulphite, NaIISOs 
(Sodii Bisulphis, U. S. P.). Under the name of antichlor the former 
is used for removing traces of chlorine from paper pulp. The sul- 
phite of magnesium (Magnesii Sulphis, U. S. P., MgS0s,6H20) is 
deposited as a white crystalline powder from the aqueous solution 
containing excess of sulphurous acid. The so-called Bisulphite of 
Lime, employed by brewers for retarding or arresting fermentation 
and oxidation, and used for various antiseptic purposes, is a solu- 
tion of sulphite of calcium (CaS03) in free sulphurous acid (II2S03), 
and is made by passing sulphurous acid gas (S02) into thin milk of 
lime. Its specific gravity varies from 1.050 to 1.070, and its potential 
strength of anhydride (S02) from 4 to 6 per cent. 
First Analytical Reaction.—To a sulphite (of sodium, for 
instance, made by passing sulphurous acid into solution of car- 
bonate of sodium) add a drop or two of dilute hydrochloric 
acid; sulphurous acid gas escapes, recognized by a peculiar 
pungent smell. 
This smell is the same as that evolved on burning lucifer matches 
that have been tipped with sulphur. It is due, probably, not to the 
gas (S02), but to sulphurous acid (H2S03) formed by the union of 
sulphurous acid gas with either the moisture of the air or that on 
Analytical Reactions ( Tests'). 304 
SALTS OF ACIDULOUS RADICALS. 
the surface of the mucous membrane of the nose. The gas is highly 
suffocating. 
Second Analytical Reaction. — To a sulphite add a little 
water, a fragment or two of zinc, and then hydrochloric acid; 
sulphuretted hydrogen will be evolved, known by its putrid 
odor and action on a piece of paper placed like a cap on the 
mouth of the test-tube, and moistened with a drop of solution 
of acetate of lead, black sulphide of lead being formed. Sul- 
phurous acid may be detected in acetic acid, or in hydrochloric 
acid, by this test. 
II2S03 + He = II2S + 3H20. 
Other Analytical Reactions. 
To solutions of neutral sulphites add nitrate or chloride of 
barium, chloride of calcium, or nitrate of silver; in each case 
white sulphites of the various metals are precipitated. The 
barium sulphite is soluble in weak hydrochloric acid; but if a 
drop or two of chlorine-water is first added, barium sulphate is 
formed, which is insoluble in acids. The other precipitates are 
also soluble in acids. The silver sulphite is decomposed on 
boiling, sulphuric acid being formed, and metallic silver set 
free, the mixture darkening in color. 
To recognize the three radicals in an aqueous solution of sul- 
phides, sulphites, and sujphates, add chloride of barium, filter, and 
wash the precipitate. In the filtrate, sulphides are detected by the 
sulphuretted hydrogen evolved on adding an acid. In the pre- 
cipitate, sulphites are detected by the odor j)f sulphurous acid pro- 
duced on adding hydrochloric acid, and sulphates by their insolu- 
bility in the acid. 
QUESTIONS AND EXERCISES. 
508. What are the differences between sulphurous acid and sul- 
phurous acid gas, sulphites and acid sulphites? 
509. State the characters of sulphurous acid gas? 
510. IIow is the official Sulphurous Acid prepared? 
511. By what test may sulphurous acid be recognized in acetic 
acid ? 
512. Give a method by which sulphites may be detected in pres- 
ence of sulphides and sulphates. 
SULPHURIC ACID AND OTHER SULPHATES. 
Many sulphates occur in nature; but the common and highly im- 
portant hydrogen sulphate, sulphuric acid, is made artificially. 
Formula of Sulphuric Acid II2S04. Molecular weight 98. SULPHATES. 
305 
Preparation of the Acid: General Nature of the Process.—Sulphur 
itself, or sometimes the sulphur in iron pyrites, is first converted into 
sulphurous acid gas by burning in air, and this gas, by moisture and 
oxygen, into sulphuric acid (SO, -f 11,0 + O = II.,S04). 
Details of the Process.—The oxygen necessary to oxidize the sul- 
phurous acid gas cannot directly be obtained from air, but indirectly, 
the agency of nitric oxide (NO) being employed—this gas becoming 
nitric peroxide (NO.,) by the action of the air, and the nitric peroxide 
again becoming nitric oxide by the action of the sulphurous acid gas, 
and so on. A small quantity of nitric oxide gas will in this way act 
as carrier of oxygen from the air to very large quantities of sulphur- 
ous acid. 
The following equations represent the successive steps :— 
S2 + 20, = 2 SO, 
Z 
Sulphur. 
i Z 
Oxygen 
(of the air). 
Z 
Sulphurous, 
acid gas. 
Sulphurous 
acid gas. 
S02 + II20 = II2S03 
Water. 
Sulphurous 
acid. 
2NO + 02 = 2NO., 
Nitric 
oxide. 
i - Z 
Oxygen 
(of the air). 
— - Z 
Nitric 
peroxide. 
H2S03 + N02 = ir,so4 + NO 
Sulphurous 
acid. 
Nitric 
peroxide. 
Sulphuric 
acid. 
Nitric 
oxide. 
On the large scale the sulphurous acid gas is produced by burning 
sulphur in furnaces; it is carried, together with the nitric vapors, 
by flues into leaden chambers, where jets of steam supply the neces- 
sary moisture; the steam also, condensing, prevents other reactions. 
The resulting dilute sulphuric acid is concentrated by evaporation 
in leaden vessels. 
The nitric oxide is in the first instance obtained from nitric acid, 
and this from nitrate of potassium or of sodium by the action of a 
small quantity of the sulphuric acid of a previous operation. 
2N&N0, + H2S04 — Na2S04 + 2IIN03 
Nitrate of 
sodium. 
Sulphuric 
acid. 
Sulphate of 
sodium. 
Nitric 
acid. 
3HaSOs + 2HN03 = 3H,S04 + IT.,0 -f 2N0 
Other P rocesses.—Sulphuric acid may be obtained by other pro- 
cesses, as by distilling the sulphate of iron resulting from the natural 
oxidation of iron pyrites by air; but it is seldom so made at the 
present day. The sulphate of iron was formerly called green vitaiol 
(p. 141), and the distilled product oil of vitriol; the latter in Elu- 
sion to its consistence and origin. 
Experiment.—For purposes of practical study, a small quantity 
may be made (as shown in fig. 39) by passing, a, sulphurous acid gas 
Sulphurous 
acid. 
Nitric 
acid. 
Sulphuric 
acid. 
Water. 
Nitric 
oxide. 306 
SALTS OF ACIDULOUS RADICALS. 
(p. 302), b, nitric oxide in small quantity (p. 286), c, air (forced 
through by aid of bellows or a gas-holder or drawn through by 
Fig. 39. 
Experimental Manufacture of Sulphuric Acid. 
a water-aspirator, e), and occasionally, d, steam (generated in a 
Florence flask) through glass tubes, nearly to the bottom of a two- 
or three-quart flask. 
S02 + H20 = II2S03; | 2N0 + 02 = 2N02; 
112S03 + N02 = II2S04 + NO. 
A slow current of sulphurous acid gas, air, and steam, and a small 
quantity of nitric oxide, will furnish, in the course of a few minutes, 
enough sulphuric acid for recognition by the first of the following 
analytical reactions. The manufacturing process may be more ex- 
actly imitated by burning sulphur in a tube placed where the flask a 
is represented in the foregoing figure, or by burning it under a 
funnel there attached; but in either of these cases strong aspiration 
must be maintained. 
Purification.—Sulphuric acid may contain arsenic, nitrous com- 
pounds, and salts. Arsenic may be detected by the hydrogen-test 
(p. 170), nitrous compounds by powdered sulphate of iron (which 
acquires a violet tint if they are present), and salts by the residue left 
on boiling a little to dryness in a crucible in a fume-chamber. If 
only nitrous compounds are present, the acid may be purified by 
heating with about one-half per cent, of sulphate of ammonium— 
water and nitrogen being produced (Pelouze). If arsenic occurs, boil SULPHATES. 
with a small quantity of hydrochloric acid, which converts the arsenic 
into chloride of arsenicum ; or heat with a little nitric acid, which 
converts arsenious (As203) into arsenic anhydride (As205), then add 
sulphate of ammonium, and distil in a retort containing pieces of 
quartz and heat by an annular-shaped burner (to prevent “ bump- 
ing see p. 277). The arsenic anhydride remains in the retort. 
(Arsenious anhydride would be carried over with the sulphuric acid 
vapors.) By distillation the acid is also purified from salts (such as 
NalIS04) which are not volatile. 
Quantivalence.—The sulphuric radical being bivalent (S04//), acid 
as well as normal sulphates may exist. Acid sulphate of potassium 
(K.IISOJ is an illustration of the former, sulphate of sodium (Na2S04) 
of the latter; double sulphates may also occur, such as that of potas- 
sium and magnesium (K2S04,MgS04,6II20). Sulphates generally 
contain water of crystallization. 
Fare sulphuric acid (II2S04) is of specific gravity 1.848. The 
best “oil of vitriol” of commerce, a colorless liquid of oily consist- 
ence, is of specific gravity 1.843, and contains 95.8 per cent, of real 
acid (II2S04). The Acidum Sulphuricum, U. S. P., should contain 
not less than 96 per cent, of 1I2S04, and have a sp. gr. not below 
1.840. The Acidum Sulphuricum Dilutum, U. S. P., contains 10 per 
cent, of the strong acid, and should have a sp. gr. of nearly 1.067. 
The Acidum Sulphuricum Aromaticum, U. S. P., a dilute acid in 
which are dissolved oil of cinnamon and tincture of ginger, contains 
about 20 per cent, of strong acid, sp. gr. 0.955. There are some 
definite compounds of sulphuric acid with water; the first (H2S04,- 
II20) may be obtained in crystals. 
Sulphuric anhydride (S03) is a white silky crystalline solid, 
having no acid properties. It is made by distilling sulphuric acid 
with phosphoric anhydride (3II2S04 + P205 = 2H3P04 + 3S03). It 
appears to unite with sulphuric acid and some other normal sul- 
phates to form compounds (R/2S04,S03) resembling in constitution 
red chromate of potassium or borax. The fuming sulphuric acid 
(II2S04,S03), formerly made at Xordhausen in Saxony, seems to be 
such a body. 
Note.—Sulphuric acid is a most valuable compound to all chemists 
and manufacturers of chemical substances. By its agency, direct or 
indirect, many, if not most, chemical transformations are effected. 
To describe all its uses would be to write a work on chemistry. 
First Analytical Reaction.—To a solution of a sulphate add 
solution of a barium salt; a white precipitate of sulphate of 
barium (BaS04) falls. Add nitric acid and boil the mixture; 
the precipitate does not dissolve. 
This reaction is as highly characteristic of sulphate as it has been 
stated to be of barium salts {vide page 102). The only error likely 
to he made in its application is that of overlooking the fact that 
nitrate and chloride of barium are less soluble in strong acid than in 
Analytical Reactions ( Tests). 308 
SALTS OF ACIDULOUS RADICALS. 
water. On adding the barium salt to the acid liquid, therefore, a 
white precipitate may be obtained, which is simply the nitrate or 
chloride of barium. The appearance of such a precipitate differs con- 
siderably from that of the barium sulphate, hence a careful operator 
will not be misled. Should any doubt remain, water should be added, 
which will dissolve the nitrate or chloride, but not affect the sulphate. 
Second Analytical Reaction.—Mix a fragment of an insoluble 
sulphate (BaS04, e. g.) with carbonate of potassium or of sodium ; 
or, better, with both carbonates, and fuse the mixture in a small 
crucible. Digest the residue when cold, in water, and filter; 
the filtrate may be tested for the sulphuric radical. 
This is a convenient method of qualitatively analyzing insoluble 
sulphates, such as those of barium and lead. 
Third Analytical Reaction.—Mix a fragment of an insoluble 
sulphate with a little alkaline carbonate on a piece of charcoal, 
taking care that some of the charcoal-dust is included in the 
mixture. Heat the little heap in the blowpipe-flame until it 
fuses, and, when cold, add a drop of acid; sulphuretted hydro- 
gen is evolved, recognized by its odor. 
This is another process for the recognition of insoluble sulphates. 
Other preparations of sulphur, and sulphur itself, give a similar re- 
sult. It is therefore rather a test for sulphur and its compounds than 
sulphates only ; but the absence of other salts can generally, if neces- 
sary, be previously determined. 
Note.—The presence of the sulphuric radical in a solution having 
been proved by the above reactions, its occurrence as the normal sul- 
phate of a metal is demonstrated by the neutral, or nearly neutral, 
deportment of the liquid with test-paper, and the detection of the 
metal—its occurrence as sulphuric acid or an acid sulphate by the 
sourness of the liquid to the taste and the effervescence produced on 
the addition of a carbonate. 
Antidote.—In cases of poisoning by strong sulphuric acid, solution 
of carbonate of sodium (common washing-soda), magnesia and water, 
etc., may be administered as antidotes. 
QUESTIONS AND EXERCISES. 
513. What is the formula of sulphuric acid, and what its molecular 
weight? 
514. How is it related to other sulphates? 
515. Write a short article on the manufacture of sulphuric acid, 
giving either diagrams or equations. 
516. How may nitrous compounds be detected in, and eliminated 
from, sulphuric acid? 
517. State the method by which the presence of arsenic is detected 
in sulphuric acid, and explain the process by which it may be re- 
moved. CARBONATES. 
309 
518. Define sulphates, acid sulphates, and double sulphates. 
519. What percentage of real acid is contained in commercial oil 
or vitriol ? 
520. State the strength of the official “ diluted ” and “ aromatic ” 
sulphuric acid. 
521. By what process is sulphuric anhydride obtained from Nord- 
inal sen sulphuric acid ? 
522. Explain the reactions which occur in testing for sulphates. 
523. Ascertain by calculation the weight of oil of vitriol (of 96.8 
per cent.) necessary for the production of one ton of dry sulphate 
of ammonium.—Ans. 1718 pounds. 
524. Name the antidotes in cases of poisoning by strong sulphuric 
acid. 
CARBONIC ACID AND OTHER CARBONATES. 
Formula of Carbonic Acid II2COs. Molecular weight 62. Formula 
of carbonic acid gas, or carbonic anhydride, commonly termed car- 
bonic acid, C02. 
Sources.—Carbonates (compounds containing the grouping CO.,) 
are very common in nature, the calcium carbonate (CaC03) being 
widely distributed as chalk, limestone, or marble. The hydrogen 
carbonate, true carbonic acid, is not known, unless indeed carbonic 
acid gas assumes that condition on dissolving in water. Such a so- 
lution (see page 85) changes the color of blue litmus-paper, and the 
gas does not; this may be because only the true acid (I12C03) affects 
the litmus, or because the gas (C02) cannot come into real contact 
with the litmus without a medium. From the commonest natural 
carbonate, carbonate of calcium, are derived the carbonic constit- 
uents of the one most frequently used in medicine and in the arts 
generally, carbonate of sodium. 
Carbonate of sodium is prepared, by “ the Leblanc process,” from 
the chief natural salt, the chloride. After the chloride has been 
converted into sulphate (salt-cake) by sulphuric acid (or by sulphur- 
ous acid, air, and steam—Ilargreave’s modification)— 
2NaCl + II2S04 = Na2S04 + 2HC1, 
the sulphate is roasted with limestone and small coal, by which car- 
bonate of sodium and sulphide of calcium are formed:— 
Na2SO, + C4 + CaC03 = CaS + Na2C03 + 4CO. 
Carbonic oxide gas and a little carbonic acid gas from the excess of 
chalk escape; the residual mass (black ash) is digested in water, in 
which the carbonate of sodium dissolves, the sulphide of calcium with 
a little oxide remaining insoluble. The solution is evaporated to 
dryness, and yields true carbonate of sodium. This is roasted with 
a small quantity of sawdust, to convert any caustic soda, resulting 
from the action of the lime on the carbonate, into normal carbonate. 
The product is soda-ash. Dissolved in water and crystallized, it 
constitutes the ordinary “soda” used for washing purposes; recrys- 310 
SALTS OF ACIDULOUS RADICALS. 
tallized and sometimes ground, it forms the official carbonate of 
sodium (Sodii Carbonas, U. S. P.) (Na2CO3,10H2O). The reaction 
is rendered more intelligible by regarding it as occurring in two 
stages: 1st, the reduction of the sulphate of sodium to sulphide by 
the carbon of the coal— 
Na2S04 + C4 = + 4C0; 
2d, the reaction of the sulphide of sodium and carbonate of calcium, 
giving soluble carbonate of sodium, thus— 
The sulphur in the residual sulphide (or, perhaps, oxysulphide) 
of calcium may be recovered by exposure to air, and the subsequent 
action of hydrochloric acid. Some hyposulphite of calcium (CaS203) 
is first formed, and the action of the acid on this and on undecom- 
posed sulphide gives chloride of calcium, water, and sulphur. A 
more promising process of recovery is that by Schaffner and Helbig. 
It consists in decomposing the calcium sulphide by magnesium 
chloride, burning the resulting sulphuretted hydrogen to sulphur- 
ous acid gas and regenerating the magnesium chloride:— 
N&2S + CaC03 = N a2C03 + CaS. 
(1) CaS + MgCl, + 2H20 = II2S + CaCL + Mg2H0: 
(2) CaCl2 + Mg2H0 + C02 = MgCl2 + CaC03+ II20. 
Another Process.—To a strong solution of common salt, bicar- 
bonate of ammonium is added, when a precipitate of bicarbonate of 
sodium occurs. The resulting chloride of ammonium may be con- 
verted into carbonate by heating with chalk, and the carbonate be 
more fully carbonated by carbonic acid gas obtained by heating the 
bicarbonate of sodium, which is thereby reduced to the ordinary 
neutral carbonate. This method is known as “ the ammonia process." 
Carbonic acid gas (C02) is a product of the combustion of all 
carbonaceous matters. It is constantly exhaled by animals and 
inhaled by plants, its intermediate storehouse being the atmosphere, 
throughout which it is equally distributed by diffusion (vide p. 24) 
to the extent of about 4 parts in 10,000. A larger proportion than 
that just mentioned gives to confined air depressing effects, 4 or 5 
per cent, rendering the atmosphere poisonous when taken into the 
Idood from the lungs. Carbonic acid, however, may be taken into 
the stomach with beneficial sedative effects ; hence, probably, much 
of the value of such effervescing liquids as soda-water, lemonade, 
and solutions of the various granulated preparations and effervescing 
powders (ride p. 86). The gas liquefies on being compressed, and 
the liquid solidifies on being evolved. Carbonic acid gas is twenty-two 
times as heavy as hydrogen, and about half as heavy again as air. 
Sulphocarbonates resemble carbonates in constitution, but contain 
sulphur in place of oxygen. 
Sulphocarbonic anhydride, CS2, commonly termed bisulphide of 
carbon or disulphide of carbon (Carbonei Bisulphidum, U. S. P.), is 
a highly volatile and inflammable liquid, easily made from its ele- 
ments. Sp. gr. 1.272; boiling-point 46° C. It may be rendered 
almost scentless by digestion with copper turnings. Its possible CARBONATES. 
311 
impurities are dissolved sulphur, sulphur oils, and sulphuretted 
hydrogen. 
Beactions. 
Synthetical and Analytical Reactions.—1. To a fragment of 
marble in a test-tube add water and then hydrochloric acid; 
carbonic acid gas (C02) is evolved, and may be conveyed into 
water or solutions of salts by the usual delivery-tube. 
This is the process of the British Pharmacopoeia, and the one 
usually adopted for experimental purposes. Passed into carbonate 
of sodium, the gas gives Sodii Bicarbonas (p. 82), and into carbonate 
of potassium, Potassii Bicarbonas (p. 70). On the large scale the 
gas is prepared from chalk or marble and sulphuric acid, frequent 
stirring promoting its escape. 
2. Pass the gas into lime-water; a white precipitate of car- 
bonate of calcium (CaCO:t) falls. Solution of subacetate of 
lead may be used instead of, and is perhaps even a more deli- 
cate test than, lime-water. 
The evolution of a gas on adding an acid to a salt, warming the 
mixture if necessary, the gas being inodorous and giving a white 
precipitate with lime-water, is sufficient evidence of the presence of 
a carbonate. Carbonates in solution of ammonia, potash, or soda 
may be detected by the direct addition of solution of lime. Car- 
bonates in presence of sulphites or hyposulphites may be detected 
by adding acid tartrate of potassium, which decomposes carbonates 
with effervescence, but does not attack sulphites or hyposulphites. 
3. Blow air from the lungs through a glass tube into lime- 
water ; the presence of carbonic acid gas is at once indicated. 
The passage of a considerable quantity of normal air through lime- 
water produces a similar effect. A bottle containing lime-water soon 
becomes coated with carbonate of calcium from absorption of atmo- 
spheric carbonic acid gas. 
4. Fill a dry test-tube with the gas by pressing the delivery- 
tube of the above apparatus to the bottom of the test-tube. 
Being rather more than once and a half as heavy as the air 
(1.529), it will displace the latter. Prove the presence of the 
gas by pouring it slowly, as if a visible liquid, into another 
test-tube containing lime-water ; the characteristic cloudiness 
and precipitate are obtained on gently shaking the lime-water. 
In testing for carbonates by bringing evolved gas into contact writh 
lime-water, the preparation and adaptation of a delivery-tube may 
often be avoided by pouring the gas from the generating-tube into 
that containing the lime-water in the manner just indicated. 
5. Pass carbonic acid gas through lime-water until the pre- 
cipitate at first formed is dissolved. The resulting liquid is a 312 
SALTS OF ACIDULOUS RADICALS. 
solution of carbonate of calcium in carbonic acid water. Boil 
the solution; carbonic acid gas escapes, and the carbonate is 
again precipitated. 
This experiment will serve to show how chalk is kept in solution 
in ordinary well-waters, giving the property of u hardness,” and how 
the fur or stone-like deposit in tea-kettles and boilers is formed. It 
should be here stated that sulphate of calcium produces similar 
hardness, and that these, with small quantities of the sulphate and 
carbonate of magnesium, constitute the hardening constituents of 
well-waters, a curd (oleate of calcium or magnesium) being formed 
whenever soap is used with such waters. An enormous amount of 
soap is wasted through the employment of hard water for washing 
purposes. The hardness produced by the earthy carbonates is 
termed “ temporary hardness,” because removable by ebullition ; 
that by the earthy sulphates “ permanent hardness,” because un- 
affected by ebullition. The addition of lime-water or a mixture of 
lime and water removes temporary hardness (reac. 2, page 311) 
and carbonate of sodium, “ washing soda,” both temporary and 
permanent hardness, in the latter case sulphate of sodium remain- 
ing in solution. Carbonate of barium (ground witherite) also de- 
composes sulphates of calcium and magnesium, sulphate of barium 
being precipitated and carbonates of calcium or magnesium formed; 
the latter and the carbonates originally in the water may then be 
precipitated by ebullition or by the action of lime-water. But the 
injurious effects of barium salts on man and the lower animals 
prevent the carbonate being used for purifying water for drink- 
ing purposes, as by accident or an unforeseen reaction a portion 
might become dissolved. 
QUESTIONS AND EXERCISES. 
525. Name the chief natural carbonates. 
526. What are the formulae of carbonic acid and carbonic acid 
gas ? 
527. Adduce evidence of the existence of true carbonic acid. 
528. Trace the steps by which the carbonic constituent of chalk 
is transferred to sodium by the process usually adopted in alkali- 
works—the manufacture of “ soda.” 
529. Carbonic acid gas is constantly exhaled from the lungs of 
animals ; why does it not accumulate in the atmosphere ? 
530. What is the effect of pressure on carbonic acid gas ? 
531. State the specific gravity of carbonic acid gas. 
532. By what processes may carbonic acid gas be obtained for 
experimental and manufacturing purposes ? 
533. Describe the action of carbonic acid gas on the carbonates 
of potassium or sodium. 
534. How may carbonic acid be detected in expired air ? 
535. To what extent is carbonic acid gas heavier than air? 
536. Work sums showing what quantity of chalk (90 per cent. OXALATES. 
313 
pure) will be required to furnish the carbonic acid necessary to 
convert one ton of carbonate of potassium (containing 83 per cent, 
of K2C03) into acid carbonate, supposing no gas to be wasted ?— 
Ans. 1500 lbs. 
537. Define “ hardness ” in water. 
538. How may the presence of carbonates be demonstrated ? 
OXALIC ACID AND OTHER OXALATES. 
Formula of Oxalic Acid II2C204,2II20. Molecular weight 126. 
Source.—Oxalates occur in nature in the juices of some plants, as 
wood-sorrel, rhubarb, the common dock, and certain lichens; but 
the hydrogen oxalate (oxalic acid) and other oxalates are all made 
artificially. The carbon of many organic substances yields oxalic 
acid when those substances are boiled with nitric acid, and an alka- 
line oxalate when they are roasted with a mixture of the hydrates 
of potassium and sodium. 
Experimental Process.—On the small scale, a mixture of nitric 
acid 10 parts, loaf sugar 2 parts, and water 3 parts, quickly yields 
the acid. Abundance of red fumes are at first evolved. On cool- 
ing, crystals are deposited. A more dilute acid, kept warm, acts 
more slowly, but yields a larger product. 
Manufacturing Process.—On the large scale, sawdust is roasted 
with alkalies, resulting oxalate of sodium decomposed by lime with 
formation of oxalate of calcium, the latter digested with sulphuric 
acid, and the liberated oxalic acid (Oxalic Acid of Commerce, B. P.) 
made commercially pure by recrystallization (Oxalic Acid Purified, 
Chemically pure Oxalic Acid.—The acid made from sugar, recrys- 
tallized two or three times, is quite pure. Commercial acid should 
be mixed with insufficient water for complete solution, and the mix- 
ture occasionally shaken. Impurities remain undissolved, and the 
saturated solution evaporated yields crystals which seldom require 
to be recrystallized. 
Quantivalence.—The elements represented by the formula C204 
are those characteristic of oxalates. They form a bivalent group- 
ing ; hence normal oxalates (R/2C204) and acid oxalates (B/HC204) 
exist. 
Salt of sorrel is a crystalline compound of oxalic acid with acid 
potassium oxalate, the crystals containing two molecules of water 
of crystallization (KHC204,II2C204,2H20). 
Oxalate of iron (Ferri Oxalas, U. S. P., FeC204,II20) is a crys- 
talline yellow powder. It may be made by precipitating a solution 
of sulphate of iron with an oxalate. When heated in contact with 
air it decomposes with a faint combustion, and leaves a residue of 
not less than 49.3 per cent, of red oxide of iron. 
First Analytical Reaction.—To solution of an oxalate (oxa- 
Analytical Reactions ( Tests'). 314 
SALTS OF ACIDULOUS RADICALS. 
late of ammonium, e. g.) add solution of chloride of calcium; 
a white precipitate falls. Add to the precipitate excess of 
acetic acid; it is insoluble. Add hydrochloric acid; the pre- 
cipitate is dissolved. 
The formation of a white precipitate on adding a calcium or ba- 
rium salt, insoluble in acetic but soluble in hydrochloric or nitric 
acid, is usually sufficient proof of the presence of an oxalate. The 
action of the liquid on litmus-paper, effervescence with carbonate 
of sodium, and absence of metals, would indicate that the oxalate is 
that of hydrogen, oxalic acid. 
Note—The barium oxalate is slightly soluble in acetic acid 
(Souchay and Lenssen), and enough may be dissolved by this acid 
from a mixed barium precipitate (produced on adding chloride or 
nitrate of barium to a solution of mixed salts) to give the foregoing 
reaction on adding chloride of calcium to the filtered acetic liquid— 
an effect sometimes useful in the analysis of mixed substances 
(Davies). 
Antidote.—In cases of poisoning by oxalic acid or salt of sorrel, 
chalk and water may be administered as a chemical antidote (with 
the view of producing the insoluble oxalate of calcium), emetics and 
the stomach-pump being used as soon as possible. 
Second Analytical Reaction.—Ileat a fragment of any dry 
common fixed metallic oxalate (an oxalate of potassium, for 
example) in a test-tube; decomposition occurs, carbonic oxide 
(CO) (a gas that will be noticed subsequently) is liberated, 
and a carbonate of the metal remains. Add water and then 
an acid to the residue; effervescence occurs. 
This is a ready test for ordinary insoluble oxalates, and is trust- 
worthy if,’ on heating the substance, no charring occurs, or not more 
than gives a gray color to the residue. Organic salts of metals de- 
compose when heated, and leave a residue of carbonate, but except 
in the case of oxalate the residue is always accompanied by much 
charcoal. Insoluble oxalates and organic salts of such metals as 
lead and silver are, of course, liable to be reduced to oxide or even 
metal by heat. Such oxalates may be decomposed by boiling with 
solution of carbonate of sodium, filtering, and testing the filtrate for 
oxalates by the chloride-of-calcium test. 
Other Analytical Reactions.—Nitrate of silver gives, with 
oxalates, white oxalate of silver (Ag2C204). Dry oxalates 
are decomposed when heated with strong sulphuric acid, car- 
bonic oxide and carbonic acid gas escaping. If much of the 
substance be operated on, the gas may be washed with an al- 
kali, the carbonic acid be thus removed, and the carbonic oxide 
he ignited ; it will be found to burn with a characteristic bluish 
flame. ■ Oxalates, when mixed with water, black oxide of 
manganese (free from carbonates), and sulphuric acid, yield 
carbonic acid gas, which may be tested by lime-water in the TARTRATES. 
315 
usual manner. Not only such insoluble oxalates as those of 
lead and silver, above referred, to, but any common insoluble 
oxalates, such as those of calcium and magnesium, may be de- 
composed by ebullition with solution of carbonate of sodium; 
after filtration the oxalic radical will be found in the clear liquid 
as soluble oxalate of sodium. 
Test of Purity.—“ Purified oxalic acid .... is entirely dissi- 
pated by a heat below 350° F.” (B. P.). 
QUESTIONS AND EXERCISES. 
539. Explain the constitution of oxalates. 
540. State how oxalates are obtained. 
541. What is the quantivalence of the oxalic radical? 
542. Give the formula of “ salt of sorrel.” 
543. Mention the chief test for oxalic acid and other soluble 
oxalates. 
544. Name the antidote for oxalic acid, and describe its action. 
545. By what reactions are insoluble oxalates recognized? 
TARTARIC ACID AND OTHER TARTRATES. 
Formula of Tartaric Acid II2C4II406, or II2T. 
Molecular weight 150. 
Source.—Tartrates exist in the juice of many fruits; but it is 
from that of the grape that our supplies are usually obtained. 
Grape-juice contains much acid tartrate of potassium (KIIC4II406), 
which is gradually deposited when the juice is fermented, as in 
making wine; for acid tartrate of potassium, not very soluble in 
aqueous liquids, is still less so in spirituous, and hence crystallizes 
out as the sugar of the grape-juice is gradually converted into 
alcohol. It is found with tartrate of calcium lining the vessels in 
which wine is kept; and it is from this crude substance, termed 
argal or argot, also from the albumenoid yeasty matter or “ lees ” 
deposited at the same time, as well as from what tartrate may be 
remaining in the marc left after the juice has been pressed from the 
grapes, that by rough crystallization “tartar,” still containing 6 or 
7 per cent, or more of tartrate of calcium (CaC4II40fi,4II20), is ob- 
tained. From the latter tartaric acid and other tartrates are pre- 
pared. In old dried grapes (Raisins; uvce, B. P.) crystalline masses 
of tartar and of grape-sugar are constantly met with. 
Cream of Tartar, purified by crystallization (Potassii Bitartras, 
U. S. P.), occurs as a “ gritty white powder, or fragments of cakes 
crystallized on one surface-,” of a pleasant acid taste, soluble in 180 
parts of cold and 6 of boiling water, insoluble in spirit.* “ If 1 
gm. of Bitartrate of Potassium be digested with 5 c.c. of diluted 
* A boiling solution of tartar yields a floating crust of minute crys- 316 
SALTS OF ACIDULOUS RADICALS. 
acetic acid for half an hour, then diluted with distilled water to 500 
c.c., the solution agitated and filtered, and 25 c.c. of the filtrate 
treated with 5 c.c. of test-solution of oxalate of ammonium, the 
liquid should not become cloudy in less than one minute, nor dis- 
tinctly turbid in less than one minute and a half (absence of more 
than 6 per cent, of tartrate of calcium).”—U. S. P. 
Quantivalence.—The elements represented by the formula C4H408 
are those characteristic of tartrates. They form a bivalent group- 
ing ; hence normal tartrates (R/2T) and acid tartrates (R/HT) exist. 
Tartrate of potassium, the Potassii Tartras of the U. S. Pharmaco- 
poeia (K2C41I406), and Rochelle Salt, or tartrate of potassium and 
sodium (KNa04II406,4II20), the official Potassii et Sodii Tartras 
(Soda Tartarata, B. P.), are illustrations of normal tartrates, wrhile 
Cream of Tartar is an example of acid tartrates. The only official 
tartrate not apparently included in these general formulae is tartar- 
emetic (Antimonium Tartaratum, B. P., Antimonii et Potassii Tar- 
tras, U. S. P.), which is sometimes regarded as the double tartrate 
of potassium and a hypothetical radical, antimonyl (SbO), thus, 
KSb0C4II406. Probably, however, it is but an oxytartrate of anti- 
mony (Sb202T) with normal tartrate of potassium (K2T) ; for there 
are several oxycompounds of antimony analogous to the oxycom- 
pounds of bismuth that have been described (p. 249), normal salts 
partially decomposed by water into oxides, and many of these oxy- 
compounds readily unite with normal salts of other basylous radicals. 
Tartar-emetic would thus be oxytartrate of antimony, with tartrate 
of potassium (Sb202T,K2T, or Sb202C4II406,K2C4II406). 
Tartaric Acid. 
Tartaric Acid (Acidurn Tartaricum, U. S. P.) is obtained by 
boiling cream of tartar (Potassii Bitartras, U. S. P.) with water, 
adding chalk till effervescence ceases, and then chloride of calcium 
so long as a precipitate hills ; the two portions of tartrate of calcium 
thus consecutively formed are thoroughly washed, treated with sul- 
phuric acid, the mixture boiled for a short time, resulting sulphate 
of calcium mostly separated by filtration, the filtrate concentrated 
by evaporation, any sulphate of calcium that may have deposited 
removed as before, and concentration continued until the solution 
is strong enough to crystallize. Tartrate of calcium from 9 ounces 
of cream of tartar requires 5 ounces by weight of sulphuric acid for 
complete decomposition. 
tals on cooling—just as milk yields a floating layer of cream, hence the 
term cream of tartar. 
“ It is called tartar,” says Paracelsus, “because it produces oil, water, 
tincture, and salt, which burn the patient as Tartarus does.” Tartarus is 
Latin (Taprapof, Tartaros, Greek) for hell. The products of its destruc- 
tive distillation are certainly somewhat irritating in taste and smell ; 
and the “salt” (carbonate of potassium) that is left is diuretic, and, 
in larger quantities, powerfully corrosive. TARTRATES. 
2KIIT + CaCOj = CaT + K2T + II/) + CO, 
Acid tartrate 
of potassium. 
Carbonate of 
calcium. 
Tartrate of 
calcium. 
Tartrate of 
potassium. 
Water. 
Carbonic 
acid gas. 
K2T + CaClj = CaT1 + 2KC1 
Tartrate of 
potassium. 
i Z 
Chloride of 
calcium. 
Tartrate of 
calcium. 
Chloride of 
potassium. 
2CaT + 2H2S04 = 2CaS04 + 2H2T 
Tartaric acid occurs in trade in colorless crystals, or the same 
powdered. It is strongly acid and readily soluble in water or spirit. 
One part in 8 of water and 2 of spirit of wine forms “ Solution of 
Tartaric Acid,” B. P. Its aqueous solution is not stable. 
Parcels of tartaric acid often contain crystals of an allotropic or 
physically isomeric modification (vide “Allotropy” and “Isomer- 
ism” in Index). It is termed Paratartaric acid (irapa, para, be- 
side) or Racemic acid (racemus, a bunch of grapes), and is a com- 
bination of ordinary tartaric acid, whose solution twists a ray of 
polarized light to the right hand (dextrotartaric or dextroracemic 
acid), and of laevotartaric or laevoracemic acid, whose solution twists 
a polarized ray to the left. Racemic acid is inactive in this respect, 
the opposite properties of its constituents neutralizing each other. 
Racemic acid is less soluble in alcohol than tartaric acid. 
Tartrate of 
calcium. 
Sulphuric 
acid. 
Sulphate of 
calcium. 
Tartaric 
acid. 
Reactions. 
Tartrate of Potassium. 
Synthetical Reaction.—To a small quantity of a strong so- 
lution of carbonate of potassium add acid tartrate of potas- 
sium so long as effervescence occurs; the resulting liquid is 
solution of normal tartrate of potassium (Potassii Tartras, 
U. S. P.) (K2T), crystals of which may be obtained on evap- 
oration. 
Rote.—This is a common method of converting an acid salt of a 
bivalent acidulous radical into a normal salt. The carbonate added 
need not be a carbonate of the same, but may be of a different 
metal; compounds like Rochelle salt (KNaT) are then obtained. 
Thus:— 
Tartrate of Potassium and Sodium. 
To a strong hot solution of carbonate of sodium add acid 
t-artrate of potassium until effervescence ceases; the resulting 
liquid is solution of tartrate of potassium and sodium ; on cool- 
ing, it yields crystals. This is the official process (Soda 
Tartarctta, B. P.; Potassii. ct Sodii Tartras, TJ. S. P.) 
(KNaC4H406,4H,0). 
Na2C03 + 2KHC4H406 = 2KNaC4H406 + H20 + C02 
Carbonate 
of sodium. 
Acid tartrate of 
potassium. 
Tartrate of potas- 
sium and sodium. 
Water. 
Carbonic 
acid gas. 
Crystals of Rochelle salt are usually halves of colorless, trans- 318 
SALTS OF ACIDULOUS RADICALS. 
parent, right rhombic prisms, slightly efflorescent in dry air, soluble 
in five parts of boiling water. Tartrate of potassium is slightly 
deliquescent, soluble in about four parts of boiling water. 
Equivalent Weights of Tartaric Acid, Carbonate of Potassium, 
Bicarbonate of Potassium, Carbonate of Sodium, Bicarbonate 
of Sodium, and Carbonates of Ammonium and Magnesium; 
repeated for 20 parts of each (and, incidentally, for other pro- 
portions). 
H2C4H4Oe — 150 
20 
IS} 
15 
10} 
11} 
17} 
19} 
25} 
28 
31} 
34} 
Carb. Potas 
K2C03 (of 84 per cent.).. = 1G4 
2*2 
20 
16§ 
Bicarb. Pot 
2(KIIC0 j) - 200 
m 
24} 
20 
14 
3} 
34 
42 
Carb. Soda (cryst.). 
Na2C03,10H20 — 286 
3S 
24} 
28} 
20 
34 
48} 
60 
Bicarb. Soda 
2(NaHC03) - 168 
m 
20 
16} 
11} 
20 
28ff 
35} 
Carb. Ammon 
(N4H16C808)+2 - 118 
15} 
14} 
11} 
8} 
14 
20 
24} 
Carb. Magnes 
(MgC03)3Mg2H0,4H20.. = 95.5 
12} 
1H 
9} 
C} 
11} 
16 
20 
Thus 20 parts (grains or other weights) of tartaric acid neutralize 
22 of carbonate of potassium, 26| of bicarbonate of potassium, 38 
of carbonate of sodium, 224 of bicarbonate of sodium, 15£ of car- 
bonate of ammonium, or 12£ of carbonate of magnesium. Other 
quantities of tartaric acid (18£, 15, 10J, 16J, 25|, 31£) saturate the 
amounts of salts mentioned in the other columns, and vice versa. 
A similar Table for Citric Acid will be found on page 322, and for 
both acids in the Appendix. These Tables afford good illustrations 
of the laws of chemical combination (page 47). The reader should 
verify a few of the numbers by calculation from the atomic weights 
of the elements concerned in the reactions, remembering that the 
salts formed are considered to be neutral in constitution. In med- 
ical practice effervescing saline draughts are often designedly pre- 
scribed to contain an amount of acid or alkali considerably in excess 
of the proportions required for perfect neutrality. 
A common form of Seidlitz Powder consists of 3 parts of Rochelle 
salt (120 grains) with 1 (40 grains) of acid carbonate of sodium (the 
mixture usually wrapped in blue paper), and 1 (40 grains) of tartaric 
acid (wrapped in white paper). W hen administered, the latter is 
dissolved in a tumbler rather more than half full of water, the former 
added, and the mixture drank during effervescence. It will be seen 
that the salts sWallowed are tartrate of potassium and sodium 
(KNaT,4H20), tartrate of sodium (Na.2T,2II20), and acid tartrate 
of sodium or of potassium. The last-mentioned salt results' because 
(for one reason) ll£ per cent. (4£ grains) of the tartaric acid is in 
excess of the quantity necessary for the formation of neutral tar- 
trate of sodium. This amount of acid salt gives agreeable acidity 
to the draught. The United States formula (Pulvis Effcrvescens 
Compositus, U. S. P.) includes rather less tartaric acid, so that only 
neutral salts are formed. TARTRATES. 
319 
Analytical Reactions ( Tests). 
First Analytical Reaction.—To solution of any normal tar- 
trate, or tartaric acid made neutral by solution of soda, add 
solution of chloride of calcium; a white precipitate, tartrate of 
calcium, falls. Collect the precipitate on a filter, wash, place a 
small quantity in a test-tube, and add solution of potash; on 
stirring the mixture the precipitate dissolves. Heat the solu- 
tion ; the tartrate of calcium is again precipitated. 
In the above reaction a fair amount of the chloride of cal- 
cium solution should be added at once, and the whole test per- 
formed without delay, or the calcium tartrate will assume a 
crystalline character, and be with difficulty dissolved by the 
potash. 
The solubility of tartrate of calcium in cold potash solution 
enables the analyst to distinguish between tartrates and citrates, 
otherwise a difficult matter. Citrate of calcium is not soluble, or 
only to a very slight extent, in the alkali. The absence of much 
ammoniacal salt must be insured, citrate as well as tartrate of cal- 
cium being soluble in solutions of salts of ammonium. 
Second Analytical Reaction.—Acidulate a solution of a tar- 
trate with acetic acid, add acetate of potassium, and well stir 
the mixture ; a crystalline precipitate of acid tartrate of potas- 
sium slowly separates. 
This reaction is not applicable in testing for very small quantities 
of tartrates, the acid tartrate of potassium being not altogether 
insoluble. The precipitate being insoluble in alcohol, however, the 
addition of spirit of wine renders the test far more delicate. One 
part of acid should yield lj of salt. 
Third Analytical Reaction.—To a neutral solution of a tar- 
trate add solution of nitrate of silver ; a white precipitate of 
tartrate of silver, Ag2C4H,06, falls. Boil the mixture; it 
blackens, owing to the reduction of the salt to metallic silver. 
Or, before boiling, add a drop, or less, of ammonia; a mirror 
will form on the tube—adhering well to the glass if the tube 
was thoroughly cleansed. Even an insoluble tartrate, placed 
in a dry tube with a few fragments of nitrate of silver and a 
drop, or less, of ammonia added, gives a mirror-like character 
to each fragment of the silver salt when the tube is gently 
rotated some inches above a flame. 
Fourth Analytical Reaction.—To a neutral or alkaline so- 
lution of a tartrate add a few drops of solution of permanganate 
of potassium, and slowly heat the test-tube; the color is dis- 
charged, an oxide of manganese being precipitated. Citrates 
only reduce the permanganate to green manganate. 320 
SALTS OF ACIDULOUS RADICALS. 
Other Reactions.—Tartrates heated with strong sulphuric 
acid char immediately. Tartaric acid and the soluble tar- 
trates prevent the precipitation of ferric and other hydrates by 
alkalies, soluble double tartrates being formed (which on evap- 
oration yield liquids that do not crystallize, but, spread on sheets 
of glass, dry up to thin transparent plates or scales). The 
Ferri et Pot assn Tartras, U. S. P. (Ferrum Tartaratum, B. P.), 
is a preparation of this kind. Tartrates decompose when 
heated, carbonates being formed and carbon set free, the gaseous 
products having a peculiar, more or less characteristic smell, 
resembling that of burnt sugar. 
546. State the origin of tartaric acid and other tartrates, and 
explain the deposition of argol, crude acid tartrate of potassium, 
during the manufacture of wine. 
547. What is the chemical formula and what are the characters 
of “cream of tartar”? 
548. Mention the formula and quantivalence of the tartaric 
radical. 
549. Write formulae of normal, acid, and double tartrates, tartar- 
emetic being treated as an oxytartrate of antimony with tartrate of 
potassium. 
550. Give equations or diagrams illustrative of the production of 
tartaric acid from cream of tartar. 
551. By what general process may normal or double tartrates be 
obtained from acid tartrate of potassium ? 
552. Work out sums proving the correctness of some of the fig- 
ures given on p. 318 as showing the saturating power of tartaric 
acid for various quantities of different carbonates, and give dia- 
grams or equations of the reactions. 
553. State the names and work sums showing the quantities of 
the salts resulting from the admixture of 120 grains of tartrate of 
potassium and sodium, 40 grains of acid carbonate of sodium, and 
40 grains of tartaric acid (Seidlitz powder). 
554. Enumerate the tests for tartrates, and explain the effects of 
heat on tartrates of the metals. 
QUESTIONS AND EXERCISES. 
CITRIC ACID AND OTHER CITRATES. 
Formula of Citric Acid II3CBII507,II20 or II3CiAq. 
Molecular weight 210. 
Source.—Citric acid (Acidum Citricum, U. S. P.) exists in the 
juice of the gooseberry, currant, cherry, strawberry, raspberry 
(liubus, U. S. P.) and many other fruits, and in other parts of CITRATES. 
321 
plants. The pulp of the fruit of Tamarindus indica (Tamarindus, 
U. S. P.) contains from l to 12 per cent, (in addition to 1.5 of tar- 
taric acid, 5 of malic acid, and 3 per cent, of acid tartrate of potas- 
sium). But it is from the lemon or lime that the acid of commerce 
is usually obtained. For this purpose concentrated lemon-juice is 
exported from Sicily, concentrated bergamot juice from the Cala- 
brian coast of South Italy, and concentrated lime-juice from the 
West Indies. The lime-fruit from Citrus bergamia is official in the 
Pharmacopoeia of India. 
Process.—The British Pharmacopoeia directs that the hot lemon- 
juice (4 pints) be saturated by powdered chalk, that is, whiting (4J. 
ounces), the resulting citrate of calcium collected on a filter, washed 
with hot water till the liquor passes from it colorless (by which not 
only the coloring-matter, but the mucilage, sugar, and other con- 
stituents of the juice are got rid of), then mixed with cold water 
(1 pint) decomposed by sulphuric acid (2£ fiuidounces in pints of 
water), the mixture boiled for half an hour, filtered, the solution 
evaporated to a density of 1.21, set aside for 24 hours, then poured 
off from any deposit of crystalline sulphate of calcium, further con- 
centrated, and set aside to crystallize. If the quantity of citrate of 
calcium to be decomposed is indefinite, the sulphuric acid may be 
added until a little of the supernatant fluid gives, after a minute or 
two, a precipitate with solution of chloride of calcium. The con- 
centrated citric solution generally crystallizes very slowly. Shaken 
violently, however, in a bottle, with a granule or two of solid acid, 
it quickly yields its citric acid in a pulverulent form, and this, 
drained and redissolved in a very small quantity of hot water, yields 
crystals fairly quickly (Warington). 
2H3CbII-07 + 3CaCOs = Ca32C8H507 + 3H20 + 3C02 
Citric acid 
(impure). 
Carbonate of 
calcium. 
Citrate of 
calcium. 
Water. 
Carbonic 
acid gas. 
Ca32C6II507 -f 3H2S04 = 2H3C6II507 + 3CaS04 
Citrate of 
calcium. 
Sulphuric 
acid. 
Citric acid 
(pure). 
Sulphate of 
calcium. 
Quantivalence.—The elements represented by the formula C6II507 
are those characteristic of citrates. They form a trivalent group- 
ing ; hence three classes of salts may exist—one, two, or three 
atoms of the basylous hydrogen in the acid, II3C6II507, being dis- 
placed by equivalent proportions of other basylous radicals. 
Citric acid itself is the only citric compound of much direct im- 
portance to the pharmacist. It usually occurs in colorless crystals 
soluble in half their weight of boiling and three-fourths of cold 
water, less soluble in spirit, and insoluble in ether. A solution of 
about 34 grains in 1 ounce of water forms a sort of artificial lemon- 
juice. Citrates heated with strong sulphuric acid to about 212° F. 
evolve carbonic oxide gas, and at higher temperatures acetone and 
carbonic acid gas. 
The artificial production of citric acid has been accomplished by 
Grimaux and Adam, who starting with glycerin, produce certain 
chloro- and cyano-derivatives, and ultimately citric acid itself. 322 
SALTS OF ACIDULOUS RADICALS. 
Action of Heat on Citric Acid.—Citric acid slowly heated first loses 
its water of crystallization ; afterwards (at 347° F.) the elements of 
another molecule of water are evolved and a residue obtained from 
which ether extracts aconitic acid (H3C6II306), identical with the 
aconitic acid (and the acid first termed equisetic) in various species 
of Aconitum and Equisetum. 
The official Lemon Juice (Limonis Succus, U. S. P.) is to be freshly 
expressed from the ripe fruit, and to contain about 7 per cent, of 
citric acid. Lime Juice contains an average of 7.84 per cent, of citric 
acid, rarely rising to 10 per cent., and very seldom falling to 7 per 
cent. Containing but little sugar and mucilage, it requires no addi- 
tion of spirit to preserve it. Lemon juice requires about 40 per cent, 
of proof spirit to prevent fermentation (Conroy). The acidity may 
be ascertained by adding solution of potash or soda (the strength of 
which has been previously determined with pure crystals of citric 
acid) till red litmus-paper is fairly turned blue. Before applying 
this test to commercial specimens, the absence of notable quantities 
of sulphuric, hydrochloric, acetic, tartaric, or other acid must be in- 
sured by application of appropriate reagents. (See also 11 Lemon 
Juice,” in Index.) 
Mistura Potassii Citratis, U. S. P., is lemon-juice completely 
neutralized by bicarbonate of potassium. It is a slightly impure but 
flavored solution of citrate of potassium. 
Equivalent Weights of Citric Acid, Carbonate of Potassium, 
Bicarbonate of Potassium, Carbonate of Sodium, Bicarbonate of 
Sodium, and Carbonates of Ammonium and Magnesium; repeated 
for 20 parts of each (and, incidentally, for other proportions.) 
Citric Acid 
HaC8H507,H20 = 210 
•20 
17 
14 
01 
161 
231 
•291 
Carb. Potas. 
(K2COa,of 84p. ct.)+-2X3 = 2461 
•231 
•20 
161 
m 
19! 
28 
341 
Bicarb. Pot 
3(KHCOa) - 300 
28! 
241 
20 
14 
24 
34 
411 
Carb. Sod. (cryst.).. 
(Na.2COa,10H2O) + 2X3.. = 429 
40 
341 
281 
20 
341 
481 
60 
Bicarb. Sod 
3(NaHCO-j) - 252 
24 
201 
161 
111 
20 
281 
35 
Carb. Ammon 
(N4H,gCjOjj) + 4X3 - 177 
101 
141 
111 
81 
14 
20 
241 
Carb. Magnes 
(MgC03),Mg2H0,4H20 
+ 8X3 = 1431 
,3i 
111 
9! 
G! 
m 
161 
20 
Thus 20 parts (grains or other weights) of citric acid neutralize 
23J of carbonate of potassium, 28J of bicarbonate of potassium, 40 
of carbonate of sodium, 24 of bicarbonate of sodium, 16f of carbo- 
nate of ammonium, or 13J of carb. of magnesium. Other quantities 
of acid (17, 14, 9f, 16J, 23f 29 j) saturate the amount of salts men- 
tioned in the other columns, and vice versa. 
This Table, the similar one for tartaric acid (p. 318), and that for 
both acids (vide Appendix) afford good illustrations of some of the 
laws of chemical combination (p. 47). The reader should verify a 
few of the numbers by calculation from the atomic weights of the CITRATES. 
323 
elements concerned in the reactions, remembering that the salts 
formed are considered to be neutral in constitution. In medical 
practice, effervescing saline draughts are often designedly prescribed 
to contain an amount of acid or alkali considerably in excess of the 
proportions required for perfect neutrality. 
Analytical Reactions ( Tests'). 
First Analytical Reaction.—To a dilute solution of any 
neutral citrate, or citric acid carefully neutralized by alkali, 
add solution of chloride of calcium and boil; a white pre- 
cipitate, citrate of calcium (Ca3Ci2), falls. Treat the precipi- 
tate, as for tartrate of calcium (p. 319) ; it is not perceptibly 
dissolved by the potash. 
A mixture of citrates and tartrates can be separated by this reac- 
tion. They are precipitated as calcium salts, and the rapidly washed 
precipitate mixed with solution of potash, diluted, and filtered ; the 
fiitrate contains the tartrate, which is shown to be present by repre- 
cipitation on boiling. The precipitate still on the filter is washed, 
dissolved in solution of chloride of ammonium, and the solution 
boiled; the citrate of calcium is reprecipitated. The presence of 
much sugar interferes with this reaction. A dilute solution of a 
citrate is not precipitated by chloride of calcium until the liquid is 
heated ; precipitation from a strong solution, also, is not thoroughly 
complete without ebullition of the mixture. This reaction is not 
thoroughly satisfactory, citrate of calcium being slightly soluble in 
alkalies, in the solutions of salts produced in the reaction, and, to a 
very slight extent, even in cold water. 
Second Analytical Reaction.—To a neutral solution of a 
citrate add solution of nitrate of silver; a white precipitate of 
citrate of silver (Ag;jCi) falls. Boil the mixture; the precipi- 
tate does not turn black as a tartrate of silver does, or only 
after long boiling. 
Third Analytical Reaction.—To a neutral or alkaline solu- 
tion of a citrate add a few drops of solution of permanganate 
of potassium and slowly heat the test-tube ; reduction to man- 
ganate only occurs, a green or reddish-green solution resulting. 
Tartrates reduce the permanganate entirely. 
Other Analytical Reactions—Citric acid forms no precipitate 
corresponding with the acid tartrate of potassium. Lime- 
water, in excess, gives no precipitate with citric acid or citrates, 
unless the solution is boiled, citrate of calcium being slightly 
soluble in cold but not in hot water; it usually precipitates tar- 
trates in the cold. Citrates, when heated with strong sul- 
phuric acid, do not char immediately. Citric acid and 
citrates prevent the precipitation of oxide of iron by alkalies, 324 
SALTS OF ACIDULOUS RADICALS. 
soluble double compounds being formed. The Ferri et Ammo- 
mi Gitras, U. S. P., is a preparation of this kind. Metallic 
citrates decompose when heated, carbonates being formed and 
carbon set free: the odor of the gaseous products is not so 
characteristic as that of tartrates. According to Cailletet, a 
cold saturated solution of red chromate of potassium turns a 
solution of tartaric acid dark brown, carbonic acid gas being 
evolved, while a solution of citric acid only slowly becomes of 
a light brown. 
QUESTIONS AND EXERCISES. 
555. What is the source of citric acid ? 
556. Describe the method by which citric acid is prepared, giving 
diagrams. 
557. Illustrate by formulae the various classes of tartrates and 
citrates. 
558. State the average proportion of citric acid in lemon-juice. 
559. Work out the sums proving the correctness of some of the 
figures given on page 322 as showing the saturating-power of citric 
acid for various carbonates. 
560. What are the tests for citrates? 
561. How are the tartrates separated from citrates? 
PHOSPHORIC ACID AND OTHER PHOSPHATES. 
Formula of Phosphoric Acid II3P04. Molecular weight 98. 
Source.—The source of the ordinary normal phosphates and of 
phosphorus itself (Phosphorus, U. S. P.) is the normal phosphate 
of calcium (Ca32P04). It is the chief constituent of the bones of 
animals, being derived from the plants on which they feed, plants 
again obtaining it from the soil. Compounds of phosphorus are 
also met with in the brain, nerves, muscles, blood, saliva, and, ac- 
cording to Kirkes, even in tissues so simple that one must assume 
that the compounds are necessary constituents of the substance of 
the primary cell. They escape from the system both in the urine 
and in the faeces. 
Pt 'ocess.—Phosphorus (P = 31) is obtained from bones by the 
following processes: The bones are burnt to remove all traces of 
animal matter. The resulting bone-earth is treated with sulphuric 
acid and water, by which an acid phosphate of calcium (CaII42P04), 
often called superphosphate of lime, is produced :— 
Ca32P04 + 2H2S04 == CaII42P04 + 2CaS04. 
The acid phosphate (strained from the sulphate and evaporated to 
dryness) is mixed with charcoal and sand, and heated to dull red- PHOSPHATES. 
325 
ness in an iron pot. At this stage water escapes and metaphosphate 
of calcium (Ca2P03, see Index) remains:— 
CaH42P04 = Ca2P03 + 2H20. 
The mixture is then transferred to a retort, and distilled at a strong 
red heat; a silicate of calcium (CaSi03) is formed and remains in 
the retort, phosphorus vapor is evolved and condensed under water, 
and carbonic oxide gas escapes:— 
2(Ca2P03) + 2Si02 + C10 = 2CaSi03 + 10CO + P4. 
It is purified by melting under water containing sulphuric acid and 
red chromate of potassium. 
Properties.—Phosphorus is a “ semi-transparent, colorless, wax- 
like solid (in sticks or cakes), which emits white vapors when ex- 
posed to the air. Specific gravity 1. 77. It is soft and flexible at 
common temperatures, melts at 110° F., ignites in the air at a tem- 
perature a little above its melting-point, burning with a luminous 
flame and producing dense white fumes. It is very poisonous. In- 
soluble in water, but soluble in ether and in boiling oil of turpen- 
tine,” also in bisulphide of carbon. It is soluble in oil which has 
been previously heated for a short time to about 482° F. to expel 
moisture: 1 part in 90 parts of dried almond oil with 9 pa ds of 
ether constituting Phosphorated Oil, Oleum Phosphoratum, U. S. P. 
A mixture, or rather a solution, of phosphorus in chloroform, mixed 
with althca, acacia, and glycerin, forms the official Phosphorus Pills 
(Pihtlce Phosphoric U. S. I\). 
Granulated or pulverulent phosphorus is obtained by placing a 
portion under equal parts of spirit and water in a bottle, standing 
the bottle in warm water till the phosphorus melts, then inserting 
the stopper (glqss, not cork), and shaking the whole till cold. 
Red or Amorphous Phosphorus.—Ordinary phosphorus kept at a 
temperature of about 450° F., in an atmosphere from which air 
is excluded, becomes red, opaque, insoluble in liquids in which 
ordinary phosphorus is soluble, oxidizes extremely slowly, and 
only ignites when heated to near 500° F. It is used in the 
manufacture of several varieties of lucifer matches, not emitting 
the poisonous, jaw-destroying fumes given by ordinary phos- 
phorus. 
Quantivalence.—The atom of phosphorus is quinquivalent, as seen 
in the pentachloride (PC1-) and oxychloride (PC130); but it often 
exhibits trivalent activity, as seen in the trichloride (PC13) and tri- 
hydride (PH3). 
Phosphide of Zinc, Zn3P2 (Zinci Phosphidum, U. S. P.), occurs 
as a grayish-black powder or in crystalline fragments having a 
metallic lustre. It may be obtained by throwing phosphorus upon 
melted zinc. 
Molecular Weight.—Phosphorus is an exception to the rule that 
the atomic weights (in grains, grammes, etc.) of elements occupy 
similar volumes of vapor at similar temperatures, the equivalent 
weight of phosphorus (81) only giving half such a volume. Hence 
while the molecular weights, that is, double the atomic weights, 326 
SALTS OF ACIDULOUS RADICALS. 
of oxygen (02 = 32), hydrogen (II2 = 2), nitrogen (N2 28), etc., 
give a similar bulk of vapor at any given temperature, the double 
atomic weight of phosphorus (P2 = 62) only gives half this bulk; 
that is, four times the atomic weight of phosphorus must be taken 
to obtain the whole bulk. It would appear therefore that the mole- 
cule of phosphorus contains four atoms (P4 -124). As with sul- 
phur, however, phosphorus in the state ordinarily known to us may 
be abnormal, and a variety yet lie found in which the molecular 
weight is double the atomic weight. 
Phosphoric Acid. 
The chief use of phosphorus in pharmacy is the formation 
of Diluted Phosphoric Acid. Phosphorus is boiled with nitric 
acid and water until dissolved. The solution, evaporated to a 
low bulk to remove nitrous compounds, and rediluted so as to 
contain 50 per cent, of acid (II3P04), constitutes the Acidum 
Phosphoricum, U. S. P., a colorless liquid of specific gravity 
1.347. If the necessary appliances are at hand, an ounce or 
two of this acid may be prepared by the official process as 
follows: Boil together, in a retort attached to a Liebig’s con- 
denser, 160 grains of phosphorus, 1000 grains of the official 
nitric acid, and 1000 grains of' water. When about 1 oz. of 
water has distilled over, it should be returned to the retort, 
and the operation repeated until the phosphorus lias dis- 
appeared. 
Phos- 
phorus. 
3P4 + 2OIINO3 + 811,0 = 12H,P04 + 20X0 
Nitric acid. 
Water. 
Phosphoric 
acid. 
Nitric 
oxide. 
The liquid remaining in the retort is then transferred to a dish 
(preferably of platinum), evaporated down to about half an 
ounce, and, lastly, diluted with distilled water until the prod- 
uct weighs 1000 grains. 
One part, by weight, of the official phosphoric acid with 
four of water yields Acidum Phosphoricum Dilution, U. S. P. 
It contains 10 per cent, of H3P04; sp. gr. 1.057. 
The use of the water in this process is to moderate the reaction. 
Strong hot nitric acid oxidizes phosphorus with almost explosive 
rapidity, hence the acid must be diluted in the first instance, and be 
rediluted, from time to time, to prevent its becoming too strong by 
loss of water. Time is saved by using a strong acid, but in that case 
constant supervision is necessary in order that water may be added, 
or the temperature otherwise reduced, when the action becomes too 
violent. Deficiency of nitric acid must also be avoided, or some 
phosphorous acid (II2PII03) will be formed. 
Markoe, also, to economize time, modifies the process by adding, 
for every ounce of phosphorus, four or five grains of iodine, and, drop PHOSPHATES. 
327 
by drop, twenty-five or thirty drops of bromine. The iodine and 
bromine unite with the phosphorus with a readiness or even violence 
that w'ould be explosive if not controlled by the presence of the cold 
fluid—further cooled, if necessary, by immersing the vessel in cold 
water. Iodide of phosphorus (PI5) and bromide of phosphorus 
(PBr5) are at once formed. These, in the presence of water, imme- 
diately yield hydriodic and hydrobromic acids (III, HBr) Jind phos- 
phoric acid. The nitric acid attacks the hydriodic and hydrobromic 
acids, forming the lower oxides of nitrogen, which escape as gas, 
water, and free iodine and bromine. The latter unite with more 
phosphorus, and the reactions are repeated. This carrying power of 
a little iodine or bromine, or both, would perhaps be indefinitely pro- 
longed if no vapor of these elements or their acids escaped with the 
gases. The phosphorus having disappeared, excess of nitric acid is 
got rid of roughly by dropping in clean rags or paper (nitric oxide, 
carbonic acid gas, and water being formed), and the last portions by 
adding oxalic acid (which even still more readily yields similar prod- 
ucts). Evaporation to a syrupy consistence 
finally removes all traces of iodine, bromine, 
oxalic acid, and moisture. The product is 
then diluted to any required extent. 
Experimental Process.—A flask, in the 
neck of which a funnel is inserted, and a 
second funnel inverted, so that its mouth 
rests within the mouth of the first, is an 
efficient and convenient arrangement of 
apparatus for this process, especially if the 
operation be conducted slowly. 
Solution of phosphoric acid evaporated to 
a specific gravity of 1.850 yields a mass of 
prismatic crystals of H3P04, especially if a 
crystal or two be dropped into the fluid 
(Cooper). Further evaporated, it leaves a 
residue which melts at a low red heat, yield- 
ing pyrophosphoric acid, and, finally, meta- 
phosphoric acid ( Glacial Phosphoric Acid). 
Phosphoric acid is also easily made from amorphous phosphorus 
(Mattison). 
Prepared from bones, phosphoric acid is apt to develop fungoid 
deposits (Jensen). Not more than traces of arsenicum or of sul- 
phur should be present in phosphorus, the former detected by sul- 
phuretted hydrogen and the latter by chloride of barium solution 
after the phosphorus has been converted by nitric acid into phos- 
phoric acid (U. S. P.). 
Quantivalence.—The elements represented by the formula P04 
are those characteristic of phosphates. The grouping is trivalent; 
hence there may exist trimetal lie or normal phosphates (M/3P04), 
dimetallic acid phosphates (M/2HP04), monometallic acid phosphates 
(M/H.,P04), and, lastly, trihydric phosphate (H3P04) or common 
phosphoric acid. These are the ordinary phosphates or orthophos- 
phates met with in nature or used in pharmacy; the rarer pyro- 
Fig. 40. 328 
SALTS OF ACIDULOUS RADICALS. 
phosphates and metaphosphates, as well as the phosphites and 
hypopliospliites, will be mentioned subsequently. 
Analytical Reactions ( Tests'). 
First Analytical Reaction.—To an aqueous solution of a 
phosphate (e. y. Na2HP04) add solution of sulphate of mag- 
nesium with which chloride of ammonium and ammonia have 
been mixed; a white crystalline precipitate of ammonio-mag- 
nesium phosphate falls (MgAmP04). 
Chloride of ammonium is added to prevent the precipitation of 
hydrate of magnesium. Arseni ate s, which have close analogy to 
phosphates, give a precipitate of similar character with the mag- 
nesium reagent. 
Second Analytical Reaction.—To a neutral aqueous solution 
of a phosphate add solution of nitrate of silver; light-yellow 
phosphate of silver (Ag3P04) is precipitated. To a portion of 
the precipitate add ammonia; it dissolves. To another portion 
add nitric acid ; it dissolves. By this reaction phosphates may 
be distinguished from their close allies the arseniates, arseniate 
of silver being of a chocolate color. 
Third Analytical Reaction.—To a solution (in a few drops 
of acid) of a phosphate insoluble in water (e. <j. Ca32P04) add 
the acetate of an alkali-metal (easily made by adding to soda 
or ammonia in a test-tube excess of acetic acid), and then a 
drop or two of solution of perehloride of iron ; yellowish-white 
ferric phosphate (Fe2P04) is precipitated, insoluble in acetic 
acid. Too much of the ferric chloride must not be added, or 
ferric acetate will be produced, in which ferric phosphate is to 
some extent soluble. 
To remove the whole of the "phosphoric radical from the solu- 
tion, add ferric chloride so long as a precipitate is produced, 
and boil; ferric phosphate and oxyacetate are precipitated. 
To obtain confirmatory evidence of the presence of phosphate 
in this precipitate, and to separate the phosphoric radical as a 
pure unmixed phosphate, collect the precipitate on a filter, 
wash, drop some solution of ammonia on it, then sulphydrate 
of ammonium, and finally wash with water; black ferrous sul- 
phide remains on the filter, while phosphate of ammonium 
occurs in the filtrate. To the filtrate add a mixture of solutions 
of sulphate of magnesium and chloride of ammonium, and 
well stir; ammonio-magnesian phosphate is precipitated. 
Fourth Analytical Reaction.—To diluted nitric acid add a 
little phosphate of calcium (or any other phosphate), and then PHOSPHATES. 
329 
solution of molybdate of ammonium, and gently heat; a yel- 
low precipitate falls. 
This precipitate contains what is termed phospho-molybdic acid, 
but is a compound of molybdie acid with phosphoric acid (about 4 
per cent, of Ii3P04) and ammonia (nearly 7 per cent.). 
Molybdate of ammonium is obtained by roasting the native 
sulphide of molybdenum (MoS2) to molybdie oxide or anhydride 
(Mo03), dissolving the latter in water, adding ammonia, evaporating, 
and crystallizing. 
Molybdates having the following formulae (M = 1 univalent atom 
of any metal) have been obtained: M2Mo04; MIIMo04; MHMo04, 
H2Mo04. According to Carrington, commercial molybdate of am- 
monium is commonly the intermediate of these three salts. Molyb- 
date of sodium has the formula Na2Mo04,II20. 
Note.—The foregoing two reactions are useful in the analysis of 
bone-earth, other earthy phosphates, phosphate of iron, and all 
phosphates insoluble in water. Only arseniates give similar appear- 
ances ; but the acid solution of these may be decomposed by agitation 
with sulphurous acid and subsequent treatment with sulphuretted 
hydrogen, arsenious sulphide, As2S3, being then precipitated. 
Other Analytical Reactions.—Solutions of barium and cal- 
cium salts give, with aqueous solutions of phosphates, white 
precipitates of the respective phosphates BaHP04, or Ba32P04, 
and CaHP04, or Ca32P04, all of which are soluble in acetic 
and the stronger acids. 
QUESTIONS AND EXERCISES. 
562. State the source of phosphorus. 
563. Give equations or diagrams explanatory of the isolation of 
phosphorus from its natural compounds. 
564. What is the composition of farmers’ “ superphosphate,” and 
how is it prepared ? 
565. Enumerate the properties of phosphorus. 
566. Mention some solvents of phosphorus. 
567. How is the official Diluted Phosphoric Acid made? 
568. Describe the precautions necessary to be observed in making 
this acid. 
569. What is the strength of the official acid ? 
570. Write formulae illustrative of all classes of orthophosphates. 
571. Mention the chief tests for soluble and insoluble phosphates. 
572. By what reactions may phosphates be distinguished from 
arseniates? 
Vanadium, V. 51.3, is a very rare element, and is here men- 
tioned only because of its exceedingly interesting relationship 
to nitrogen, phosphorus, and arsenicum. Discovered but not 330 
SALTS OF ACIDULOUS RADICALS. 
isolated by Sefstrom, and its compounds investigated by Berze- 
lius, it has only of late years been obtained in the free state 
and fully studied by lioscoe. 
Oxides of Vanadium. 
v205, v2o4 va, va, v2o. 
Orthovanadates R/V04 
Pyro vanadates 11/V 207 
Metavanadates R/V03 
Oxides of Nitrogen. 
NA, n204, NA, n202, n20. 
Orthophosphates R/P04 
Pyrophosphates R/P207 
Metaphosphates R'P03 
Isomorphous Minerals. 
Apatite 3(Ca32P04),CaFl2 
Pyromorphite 3(Pb32P04),PbCl2 
Mimetesite 3(Pb32As04),PbCl2 
Vanadinite 3(Pb32V04),PbCl2 
BORACIC ACID AND OTHER BORATES. 
Formula of Boracic Acid II3B03. Molecular weight 62. 
Tim composition of artificial boracic acid is expressed by the for- 
mula H3B03 (Acidum Boricum, U. S. P.); but at a temperature of 
212° F. this body loses the elements of water and yields metaboracic 
acid, HB02, which at higher temperatures becomes boracic anhydride 
(BA)- The latter acid exists in the jets of steam ( fumerolles or 
sujfioni) that issue from the earth in some districts of Tuscany, and 
collects in the water of the lagoni (lagoons or little lakes) formed at 
the orifices of the steam-channels. This acid liquid, evaporated by 
aid of the waste natural steam and neutralized by carbonate of so- 
dium, gives common borax (2NaB02,2HB02,9H20), possibly an acid 
metaborate of sodium with water of crystallization. It occurs “ in 
transparent colorless crystals, sometimes slightly effloresced, with a 
weak alkaline reaction ; insoluble in rectified spirit, soluble in water.” 
' Native borax, or tincal, and other borates are also found in Thibet, in 
Nevada, Peru, Chili, and recently in California, in the Clear Lake 
district. The introduction of the natural borax from California has 
reduced the price to about one-half its former amount. This borax 
is represented as forming large portions of the crystalline bed of a 
dried-up lake. Fused borax readily dissolves metallic oxides, as 
will have been already noticed in testing for cobalt and manganese. 
Hence, besides its use in medicine (Sodii Boras, U. S. P.), it is em- 
ployed as a flux in refining and other metallurgic and ceramic 
operations. 
Quantivalence.—The boracic radical is trivalent (B03///), the 
metaboracic, univalent (BO/); they have not been isolated. The 
element boron, like carbon, occurs in the amorphous, graphitoidal, 
and crystalline conditions. It is a trivalent element (B/V/), yielding 
definite salts, such as the chloride (BC13) and fluoride (BF3). Its 
atomic weight is 11. BORATES. 
331 
Reactions. 
First Synthetical Reaction.—To a hot solution of a crystal 
of borax add a few drops of sulphuric acid and set aside; on 
cooling, crystalline scales of boracic acid (H3B03) are deposited. 
They may be purified by collecting on a filter, slightly washing, 
drying, digesting in hot alcohol, filtering, and setting aside; 
pure boracic acid (B. P.) is deposited. The acid may also be 
recrystallized from water. Fifty grains dissolved in one ounce 
of rectified spirit constitute “ Solution of Boracic Acid,” B. P. 
Boracic acid is a very weak compound. It only slowly decomposes 
carbonates, and resembles alkaline substances in coloring turmeric 
brown. Indeed the alkalinity of borax is as great as if it contained 
no acidulous radical. Boracic acid is said to be itself an antiseptic, 
but Endemann states that in preserving foods it acts by converting 
phosphates into acid phosphates, and that the latter are the antisep- 
tic principles. 
Second Synthetical Reaction.—Mix together 1 part of boracic 
acid, 4 of acid tartrate of potassium, and 10 or 20 of water; 
evaporate to a syrupy consistence, spread on plates, and set aside 
for dry scales to form. The resulting substance is, in water, far 
more readily soluble than either of its constituents, and is 
known as boro-tartrate of potassium or soluble cream of tartar. 
The Prussian tartarus boraxatus differs from the foregoing 
French variety in containing 1 part of borax to 3 of acid tar- 
trate of potassium. 
Analytical Reactions (Tests). 
First Analytical Reaction.—Pip a piece of turmeric-paper 
(paper soaked in tincture of turmeric tubers and dried) into a 
solution of boracic acid ; it is colored brown-red, as by alkalies. 
The usual way of applying this test is as follows: Add to a solu- 
tion of any borate a few di’ops of hydrochloric acid ; immerse half of 
a slip of turmeric-paper in the liquid, then remove the hydrochloric 
acid by drying the paper over a flame. Concentrated hydrochloric 
acid and ferric chloride produce a somewhat similar effect. 
Second Analytical Reaction.—To a fragment of a borate or 
metaborate (borax, for example) in a small dish or watch-glass 
add a drop of sulphuric acid, and then a little alcohol, warm 
the mixture and set light to the spirit; the resulting flame 
will be tinged of a greenish color at its edges by the volatilized 
boracic acid or boracic anhydride. 
The liquid should be well stirred while burning. Salts of copper 
and some metallic chlorides produce a somewhat similar color. The SALTS OF RARER ACIDULOUS RADICALS. 
flame test may also be applied to a little of a mixture of the borax 
with strong sulphuric acid on a platinum wire. Glycerin may be 
used in place of sulphuric acid (lies). 
Other Analytical Reactions.—In solutions of borax barium 
salts give a white precipitate of barium metaborate (Ba2B02) 
soluble in acids and alkaline salts. Nitrate of silver gives 
metaborate of silver (AgB02) soluble in nitric acid and in 
ammonia. Chloride of calcium, if the solution is not too di- 
lute, gives white borate of calcium. 
QUESTIONS AND EXERCISES. 
573. Illustrate the relation of vanadium to nitrogen by formulae of 
compounds of each element. 
574. Describe the preparation of borax. 
575. Give the formulae of boracic acid, metaboracic acid, and 
borax. 
576. Mention the tests for borates or metaborates. 
The foregoing acids and other salts contain the only acidulous 
radicals that are commonly met with in analysis or in ordinary 
medical or pharmaceutical operations. There are, however, many 
others which occasionally present themselves. The chief of these 
will note be shortly noticed; they are arranged in alphabetical order 
to facilitate refei'ence. 
Anemonic Acid.—Pulsatilla, U. S. P., is the official name for the 
herbs of Anemone Pulsatilla, A. pratensis, and A. patens. These, 
together with several species of Ranunculus, on distillation with 
water yield a heavy, yellow, acrid oil, which, in contact with water, 
yields crystalline poisonous anemonin (C13I11206) and amorphous 
anemonic acid (C15IIu07). 
Benzoic Acid (HC7H502) and other Benzoates.—Slowly 
heat a fragment of benzoin (Gum benzoinum) (.Benzoinum, 
U. S. P.) in a test-tube ; benzoic acid (Acidum Benzoicum, U. S. 
P.) rises in vapor and condenses in small, white, feathery plates 
and needles, on the cool sides of the tube. If the benzoin is 
first mixed with twice its weight of sand or roughly powdered 
pumice-stone, and the heat very cautiously applied, the product 
will be less likely to be burnt, and a larger quantity be yielded. 
By repeated sublimation 10 to 15 per cent, may be obtained. 
A more economical process is to boil the benzoin with one- 
SALTS OF RARER ACIDULOUS RADICALS. BENZOATES. 
fourth of its weight of lime, filter, concentrate, decompose the 
solution of benzoate of calcium by hydrochloric acid, collect 
the precipitated benzoic acid, press between paper, dry and 
sublime in a tube or other vessel. 
2HC7HA + Ca2HO = Ca2C7HA + 2H20 
Benzoic acid 
(impure). 
Hydrate of 
calcium. 
Benzoate of 
calcium. 
Water. 
Ca2C7H502 + 2II Cl = CaCl2 + 2HC7H502 
Benzoate of 
calcium. 
Hydrochloric 
acid. 
Chloride of 
calcium. 
Benzoic acid 
(pure). 
There is always associated with the product a minute quantity of 
a volatile oil (styrol?) of agreeable odor, suggesting that of hay. 
Benzoic acid is also prepared on a large scale artificially from 
naphthalene, one of the crystalline by-products in the distillation of 
coal for gits, 'fhe naphthalene is oxidized by nitric acid to naphthalic 
or phthalic acid :— 
. c10H8 + 402 = h c8ha + h2c204 
Naphthalene. Oxygen. Phthalic acid. Oxalic acid. 
The phthalic acid is neutralized by lime, and the phthalate of calcium 
heated with hydrate of calcium in a covered vessel at a temperature 
of about 640° F. for several hours. Benzoate and carbonate of cal- 
cium are formed, and from the powder the benzoic acid is set free 
by action of hydrochloric acid. 
2CaC8II404 + Ca2IIO = Ca2C7H502 + 2CaC03 
Phthalate of 
calcium. 
Hydrate of 
calcium. 
Benzoate of 
calcium. 
Carbonate of 
calcium. 
The crystalline deposit formed when essential oil of almonds 
(hydride of benzoyl or benzoic aldehyd) is exposed to the air is 
benzoic acid. 
2C7H5OH + 02 = 2C7II5OIIO or 2IIC7II502 
Hydride of 
benzoyl. 
Oxygen. 
Hydrate of 
benzoyl. 
Benzoic 
acid. 
Benzoic acid is also obtained from hippuric acid (p. 336). Such 
acid, if not thoroughly purified, may have an urinoid odor. Jacob- 
sen prepares benzoic acid from benzotrichloride (trichloromethyl- 
benzol, C8H5CC13), one of the trichlortoluenes, by heating with gla- 
cial acetic acid and chloride of zinc. This acid, if not very highly 
purified, may give a green color to flame when placed on platinum 
wire with a little oxide of copper. In artificial benzoic acid the 
fragrant volatile oil characteristic of the natural acid is, of course, 
absent; while in some specimens the odor of oil of bitter almond 
may be detected. 
Benzoate of Ammonium.—To a little benzoic acid add a 
few drops of solution of ammonia; it readily dissolves, form- 
ing benzoate of ammonium (Ammonii Benzoas, U. S. P.) 
(NH4c7HA). 
or 334 
SALTS OF RARER ACIDULOUS RADICALS. 
HC7H502 + NIIJIO = NH4C.TIA + H,0 
Benzoic acid. 
Ammonia. 
Benzoate of 
ammonium. 
Water. 
On evaporation, acid crystals or, ammonia being added, neu- 
tral crystals of benzoate of ammonium are deposited. Benzoate 
of sodium (Sodii Benzoas, U. S. P.), NaC7H502 may be 
similarly prepared. 
Properties.—Benzoic acid is also soluble in other alkaline 
liquids, forming benzoates. It is slightly soluble in cold water, 
more so in hot, and readily soluble in rectified spirits. It 
melts at 248° F., and boils at 4G2°, volatilizing with only a 
slight residue. Heated with lime it yields benzol. It dis- 
solves in cold oil of vitriol without decomposition, is again 
deposited on dilution, and the traces of odoriferous and other 
substances present in the acid from benzoin only slightly color 
the fluid, even on gently warming. 
Tests for Benzoates.—To a portion of the above solution of 
benzoate of ammonium add a drop or two of sulphuric or hydro- 
chloric acid; a white crystalline precipitate of benzoic acid 
separates. To another portion, carefully made neutral, add a 
drop or two of neutral solution of perchloride or persulphate 
of iron ; reddish ferric benzoate is precipitated. 
Cinnamic Acid (C9H902).—Benzoic acid is distinguished 
from an allied body, cinnamic acid (occurring in Balsams of 
Peru, Tolu, and Storax, and sometimes in Benzoin), by not 
yielding hydrate of benzoyl (C7H5OH) (oil of bitter almonds) 
when distilled with chromic acid—that is, with a mixture of 
red chromate of potassium and sulphuric acid—or when rubbed 
with half its weight of permanganate of potassium. Old hard 
balsam of tolu yields it on boiling with lime and water and 
percipitating by hydrochloric acid. Jacobsen makes it arti- 
ficially by the prolonged reaction of glacial acetic acid and ben- 
zodiehloride in the presence of chloride of zinc. 
Carminic Acid (C14II1408).—This is the coloring principle of 
cochineal (Coccus, U. S. P.). The carmine of trade, when unadul- 
terated (vide Pharmaceutical Journal, 1859-60, p. 546), is carininic 
acid united with one or two per cent, of alumina, or, occasionally, 
of oxide of tin or albumen. It should be wholly soluble in solu- 
tion of ammonia, giving an apparently clear rich purple fluid. Car- 
mine, with French chalk, or starch, constitutes face-rouge or animal 
rouge. 
Merrick tests the relative value of several samples of cochineal 
or carmine by observing how much solution of permanganate 
of potassium is required to change the color of a decoction to 
faint pink. 
Cetraric Acid (II2C34TI30O16) is the bitter principle of Iceland CYANATES. 
moss {Cetraria, U. S. P.). In the lichen it ia associated with much 
starch. 
Chrvsophanic Acid (C14II10O4).—This acid is the chief coloring- 
matter of various species of rhubarb-root {Rheum, U. S. P.), and, 
under the name of parietinic acid, of various common yellow 
lichens. The author also found it to form four-fifths of old “ Chrys- 
arobine,” a name given by Kemp to the pith, etc. of a leguminous 
tree {Andira Araroba). Chrysarobine or crysarobin {Chrysarobinum, 
U. S. P.) is also known as Araroba Powder, Bahia Powder, Brazil 
Powder, Goa Powder, and Ringworm Powder. Recent chrysarobin 
has been shown by Liebermann and Seidler to have the formula 
C:J0II26<)7; this, by oxidation and elimination of water, yields the 
chrysophanic acid occurring in old chrysarobin. Chrysophanic acid 
may be obtained in crystals of a golden-yellow color, hence the 
name (from xPva°S, chrusos, gold, and <f>ai.vu, phaino, I shine). Its 
synonyms are Rhaponticin, Rheic acid, Rhein, Rheumin, Rheubarb- 
aric acid, Rheubarbarin, Rumicin. Chrysophanic acid, black, red- 
brown, and red resins (Aporetine, Fhceoretine, and Erythroretine), a 
bitter principle, and tannic acid, are considered to be the conjoint 
source of the therapeutic properties of rhubarb. Chrysophanic acid 
is also contained in several species of Rumex or Dock. “Rumicin” 
is a name given to a preparation of the root of Rumex crispus, or 
Yellow Dock {Rumex, U. S. P.). 
Cornic Acid, or Corn in.—This is, according to Geiger, the crys- 
talline bitter principle of the bark (Cornus, U. S. P.) of Cornus Jior- 
ula. A crystalline resin is also present. 
Cyanic Acid (HCyO) and other Cyanates.—The valu- 
able reducing power of cyanide of potassium (KCy) (or ferro- 
cyanide, K4Fcy) on metallic compounds is due to the avidity 
with which cyanate (KCyO) is formed. 
Process.—Fuse a few grains of cyanide of potassium in a 
small porcelain crucible, and add powdered oxide of lead; a 
globule of metallic lead is at once set free, excess of the oxide 
converting the whole of the cyanide of potassium into cyanate 
of potassium. 
Urea.—Cyanate of potassium (KCNO), or, better, cyanate of lead 
(Pb2CNO), treated with sulphate of ammonium, yields cyanate of 
ammonium (NII4CNO); and solution of cyanate of ammonium, 
when simply heated, changes to artificial urea (CII4N20), the 
most important constituent of urine, and the chief form in which 
the nitrogen of food is eliminated from the animal system. The 
process will be more fully described subsequently in connection 
with Urea. 
Formic Acid (IICII0.2).—The red ant {Formica rufa) and several 
other insects, when irritated, eject a strongly acid, acrid liquid, hav- 
ing a composition expressed by the above formula, and which has 
appropriately received the name of formic acid ; it is also contained 336 
SALTS OF RARER ACIDULOUS RADICALS. 
in the leaves of the stinging-nettle. (According to Church the sting 
of the wasp is alkaline.) 
Process.—It may be artificially prepared by heating equal 
weights of oxalic acid and glycerin to a temperature of from 
212° to 220° F. for fifteen hours, and then distilling the mix- 
ture with a considerable volume of water. The formic acid 
slowly passes over, the glycerin being regenerated. The dilute 
acid may be concentrated by neutralizing with carbonate of 
lead, filtering, evaporating to a small bulk, collecting the 
deposited crystalline formate of lead, drying, decomposing in a 
current of sulphuretted hydrogen, separating the resulting 
syrupy acid, and passing air through the product until all sul- 
phuretted hydrogen is removed. The following are the chief 
reactions:— 
C3Ha3HO + H2CA C3H5HOCA + 2H20 
Glycerin. 
Oxalic 
acid. 
Hydrato-oxalate 
of glyceryl. 
M'ater. 
Ilydrato-oxalate 
of glyceryl. 
C:JT5HOCA + 2H20 = C3II53HO + HCIIO, + C02 
Water. 
Glycerin. 
Formic 
acid. 
Carbonic 
anhydride. 
Formic arid may be instructively though not economically pre- 
pared by the oxidation of methylic alcohol (wood spirit), just as 
acetic acid and valerianic acid are obtained from ethylic alcohol and 
amylic alcohol respectively. 
Wood- 
spirit. 
CH.JIO + 0, = IICTI02 + H„0 
Oxygen. 
z , 
Formic 
acid. 
Water. 
Tests.—Formic acid does not char when heated alone or with sul- 
phuric acid, but splits up into carbonic oxide gas and water. It 
is recognized by this property and by its reducing action on 
salts of gold, platinum, mercury, and silver. It is solid below 
32° F. 
Gallic Acid.—See Tannic Acid. 
Hemidesmic Acid.—The supposed active principle of hemi- 
desmus root (Hemidesmi radix, B. P.). 
IIippuric Acid (HC9H8N03) is a constituent of human urine 
(much increased on taking benzoic acid), but is best prepared from 
the urine of the horse (hence the name, from in-nog, hippos, a horse), 
or, better, from that of the cow. To such urine add a little milk of 
lime, boil for a few minutes, remove precipitated phosphates by fil- 
tration, drop in hydrochloric acid until the liquid, after well stirring, 
is exactly neutral to test-paper, concentrate to about one-eighth the 
original bulk, and add excess of strong hydrochloric acid; impure 
hippuric acid is deposited. From a solution of the impure acid in 
hot water chlorine gas removes the color, and the liquid deposits 337 
FERROCYANIDES. 
crystals of pure hippuric acid on cooling. Its constitution is that of 
benzoic ghjcocine, CjH2H2(CtH50)N02. 
Tests.—To a solution of hippurate add neutral solution of ferric 
chloride; a brown precipitate (ferric hippurate) results. Salts of 
silver and mercury give white precipitates. Heat hippuric acid in 
a test-tube; it chars, benzoic acid sublimes, and vapors of charac- 
teristic odor are evolved; they contain, amongst other bodies, hy- 
drocyanic acid and a substance smelling somewhat like Tonka bean. 
The crystalline form of hippuric acid is characteristic ; it will be 
described in connection with the subject of urine. 
577. Give the preparation, composition, properties, and tests of 
benzoic acid, employing equations or diagrams. 
578. What is the nature of carmine? 
579. Name the bitter principle of Iceland moss. 
580. Mention the coloring principle of rhubarb. 
581. To what is rhubarb considered to owe its medicinal activity? 
582. How is cyanate of potassium prepared, how converted into 
an ammonium salt, and what are the relations of the latter to urea? 
583. Give the formulae of cyanic acid, cyanate of ammonium, and 
urea. 
584. What is the chemical formula of formic acid ? 
585. Describe the artificial production of formic acid. 
586. Describe the relation of formic acid to wood spirit, 
587. State the sources, characters, and tests of hippuric acid. 
QUESTIONS AND EXERCISES. 
HyDROFERROCYANIC AoiD (H4Fe//Cy6, Or H4Fcy////) AND OTHER 
Ferrocyanides.—The ferroeyanide of most interest is that of 
potassium (Potassii Ferrocyanidum, U. S. P.), the yellow prussiate 
of potash (Potassce Prussias Fluva, B. P.) (K4FeC6N6,3II20), the 
formation of which was alluded to in connection with hydrocyanic 
acid (see page 276). It cannot be regarded as simply a double salt 
of cyanide of potassium with cyanide of iron (FeCy2,4KCy), its 
chemical properties being entirely different from either of those sub- 
stances ; moreover, unlike cyanide of potassium, it is not poisonous. 
Most of its reactions point to the conclusion that its iron and cyano- 
gen are intimately united to form a definite quadrivalent radical ap- 
propriately termed ferrocyanogen (FeCyfi, or Fey). One part of ferro- 
cyanide of potassium in 20 of water forms the official “ Solution of 
Yellow Prussiate of Potash,” B. P. 
Texts.—Many of the ferrocyanides are insoluble, and are 
therefore precipitated when solution of ferroeyanide of potas- 
sium is added to the various salts. Those of iron and copper, 
being of characteristic color, are adopted as tests of the pres- 
ence of the metals or of the ferrocyanogen, as the case may be. 338 
salts of rarer acidulous radicals. 
To solution of ferrocyanide of potassium add a ferric salt; 
ferrocyanide of iron (Fe4Fey3) (Prussian blue) is precipitated. 
3K4Fcy -f 2(Fe23S04) = Fe4Fcy3 + 6K2S04. 
To another portion add solution of a copper salt; reddish- 
brown ferrocyanide of copper (Cu2Fcy) is precipitated. 
Note.—The ferrocyanogen in ferrocyanide of potassium is broken 
up when the salt is heated with sulphuric acid, carbonic oxide 
being evolved if the acid is strong (that is, ordinary oil of vitriol 
—1I2S04 with 3 to 4 per. cent of water), and hydrocyanic acid 
if weak:— 
K4FeC6N6,3H20 + 3II20 + 6H2S04 = 2K2S04 + FeS04 
+ 3(NH4)2S04 + 6C0. 
2K4FeCy6 -j- 6II2S04 + &’II20 = FeK2FeCy6 + 6KHS04 
+ 6HCy + a:II20. 
Hydrocyanic Acid has already been described. ( Vide p. 277.) 
Carbonic Oxide (CO).—Heat two or three fragments of ferrocy- 
anide of potassium with eight or ten times their weight of sulphuric 
acid, and as soon as the gas begins to be evolved remove the test- 
tube from the flame; for the action, when once set up, proceeds 
somewhat tumultuously. Ignite the carbonic oxide at the mouth of 
the tube; it burns with a pale blue flame, the product of combustion 
being carbonic acid gas (C02). 
Carbonic oxide is a direct poison. It is generated whenever coke, 
charcoal, or coal burns with an insufficient supply of air. Hence 
the danger of open fires in the more or less closed apartments of or- 
dinary dwellings. 
Carbonic oxide may also be obtained from oxalic acid. (Vide 
p. 314.) 
Hydroferridcyanic Acid (H„Fe'"2Cy12, or FFgFdey'’1) and 
other Ferridcyanides.—Pass chlorine gas slowly through 
solution of ferrocyanide of potassium until the liquid, after 
frequent shaking, ceases to give a blue precipitate, when a 
minute portion is taken out on the end of a glass rod and 
brought into contact with a drop of a dilute solution of a ferric 
salt; it now contains ferridcyanide of potassium (K6Fe'"2Cy]2, 
or KTfiFdcyVI), red prussiate of potash (B. P.), as it is termed 
from the color of its crystals. Excess of chlorine must be 
carefully avoided, as chloride of cyanogen and other compounds 
are then formed. 
2K'4Fe"Cy'6 + C1'2 = 2K'C1' + K'6Fe'"2Cy'12. 
Another Process.—To a cold solution of yellow prussiate of 
potash so much hydrochloric acid is added as will take two 
atoms of potassium from two molecules of the salt, and then a FLUORIDES. 
339 
cold clear solution of bleaching-powder till ferric chloride gives 
no reaction. Any excess of acid is then neutralized with chalk 
and the solution evaporated to crystallization (Rhien). 
Note.—The removal of two atoms of potassium from the ferro- 
cyanide is the only change of composition that occurs; but the 
ferrocyanogen is altered in quality, its iron passing from the ferrous 
to the ferric condition, from bivalent to trivalent activity, altered to 
a condition in which it no longer precipitates ferric salts, but, on 
the other hand, gives a dark-blue precipitate with ferrous salts. 
The radical is distinguished as ferridcyanogen. 
Ferridcyanide of potassium may also be prepared by a modifica- 
tion of the foregoing method in which nascent instead of free chlorine 
is employed (Wenzell). Take of Bichromate of Potassium 1 part, 
Ferroeyanide of Potassium Cryst. 5.72 parts, Hydrochloric Acid, of 
spec. grav. 1.16, 3 parts by weight, Water 60 parts. Dissolve the 
two salts in hot water, add the acid, heat to boiling, continuing the 
ebullition, replacing the water evaporated during the process until 
a portion of the filtered liquid is not precipitated on the addition of 
solution of ferric chloride. AYhen reaction is completed, filter the 
liquid and wash the hydrate of chromium, unite the liquids, and 
concentrate to crystallization. If the evaporated liquid possess an 
acid reaction, the addition of caustic potash, in sufficient quantity to 
cause a weak alkaline reaction, will greatly facilitate the subsequent 
crystallization. 
6(K4FeCy6) -f K2Cr20. + 8IIC1 = 3(K6Fe2Cy12) 
-j- 8KC1 + fl20 + Cr26HO. 
Test.—To a portion of the solution add solution of ferrous 
sulphate ; a precipitate falls. This precipitate is ferridcyanide 
of iron (Turnbull’s blue), Fe"3Fe'"2Cy'12, or Fe"3FdcyVI. 
KBFdcy + 3FeS04 - Fe3Fdcy + 3K,S04. 
It will be noticed that the change in the condition of the iron 
keeps up the balance of the atomic values of the various parts of 
the radicals or of the salts; the quantivalential equilibrium is 
maintained. 
A solution of 1 part of ferridcyanide of potassium in 20 of water 
constitutes the “ Solution of Red Prussiate of Potash,” B. P. 
Hydrofluoric Acid (HF) and other Fluorides.—. 
Molecular weight of HF, 20. The chief use of hydrofluoric 
acid is in the etching on glass. The operation, performed on 
the small scale, also constitutes the best test for fluorine, the 
elementary radical of all fluorides. 
Process and Test.—Warm any odd piece of window-glass, 
having an inch or two of surface, until a piece of beeswax 
rubbed on one side yields a thin oily film. When cool make a 
cross, letter, or other mark on the glass by pressing a pointed 340 
SALTS OF RAKER ACIDULOUS RADICALS. 
piece of wood, a penknife, or file, through the wax. Place a 
few grains of powdered fluor spar, the commonest natural fluo- 
ride, in a porcelain crucible (or a lead cup), add a drop or two 
of sulphuric acid, cover the crucible with the prepared glass, 
waxed side downwards, and gently warm the bottom of the 
crucible in a fume-chamber or in the open air, in such a way 
as not to melt the wax. After a few minutes remove the 
glass, wash the waxed side by pouring water over it, scrape 
off most of the wax, then warm the glass, and wipe off the 
remainder; the marks made through the wax will be found to 
be permanently etched on the glass; the acid has eaten into or 
etched (from the German dtze.n, to corrode) the glass. 
In the above operation the fluoride of calcium and sulphuric acid 
yield hydrofluoric acid, thus — 
CaF2 + II2S04 = CaS04 + 2IIF. 
The hydrofluoric acid gas and the silica of the glass then yield 
gaseous fluoride of silicon (SiF4), which escapes, and water, thus:— 
4IIF + Si02 = 2II20 + SiF4. 
The silica, being removed from the glass, leaves farrows or etched 
portions. 
Note.—In the experiment just described, the liberated hydrofluoric 
acid also attacks the siliceous glazing of the porcelain crucible; so 
that in important cases, where search is made for very small quanti- 
ties of fluorine, vessels of platinum or lead must be employed. 
Uses.—The aqueous solution of hydrofluoric acid used by etchers, 
and commonly termed simply hydrofluoric acid, or “ fluoric” acid, is 
prepared in leaden stills and receivers, and kept in leaden or gutta- 
percha bottles. Except these materials, as well as platinum and 
fluor spar, hydrofluoric acid rapidly attacks any substance of which 
bottles and basins are usually made. It quickly cauterizes the skin, 
producing a painful, slow-healing sore. 
Quantivalence.—The atom of fluorine, like that of chlorine, bro- 
mine, or iodine, is univalent (F'). The great analogy existing be- 
tween these radicals extends to their compounds. 
Fluorine is said to be a colorless gas; but, from the avidity with 
which it combines with all elements (except oxygen), it is so difficult 
of isolation as hitherto to preclude satisfactory study of its physical 
properties. 
Hypopiiosphorous Acid (H:iP02, or HPH.,02) and other 
Hypophosphites.—Boil together, in a fume-chamber, a grain 
or two of phosphorus, a few grains of slaked lime, and about 
a quarter of an ounce of water until phosphoretted hydrogen, 
a spontaneously inflammable, badly-smelling gas, ceases to be 
evolved. The lime must not be in great excess or the hypo- 
phosphite will be converted into phosphate as fast as formed. IIYPOPHOSPHTTES. 
341 
The mixture, filtered, and excess of lime removed by car- 
bonic acid gas, yields solution of hypophosphite of calcium 
(Ca2PH202) (Calc it Hypophosphis, U. S. P.). 
2P4 + 6H..0 + 3CaH202 = 3(Ca2PH202) + 2PH3. 
The solution, when concentrated by evaporation, has been known 
to explode, probably from formation of phosphoretted hydrogen. 
This may be prevented, it is said, by evaporating at a low tempera- 
ture, especially towards the close of the operation; or by adding 
alcohol, which decomposes any traces of liquid phosphoretted hydro- 
gen (PII2) or solid phosphoretted hydrogen (P2II) which possibly 
may be present, and to which it is conceivable explosion may be 
due. The aqueous solution may conveniently contain one-fourth or 
one-third of real acid. 
Phosphoretted Hydrogen (PHg).—The above reaction is also that 
by which phosphoretted hydrogen, the third hydride of phosphorus, 
may be prepared. If the gas is to be collected, the phosphorus and 
water may first be boiled in a flask until a jet of spontaneously in- 
flammable phosphorus vapor escapes, with steam, from the end of the 
attached delivery-tube. Strong solution of caustic potash or soda is 
next very gradually poured into the flask through a funnel tube pre- 
viously fitted into the cork, the liquid being kept boiling. Phospho- 
retted hydrogen is then evolved, and, if the delivery-tube dip under 
water, may be collected, or allowed to slowly pass up through the 
water bubble by bubble so as to form the peculiar rings of smoke 
(phosphoric anhydride) characteristic of the experiment. 
Hypophosphite of calcium (Ca2PH202) (Calcii Hypophosphis, U. S. 
P.) may be obtained in crystals by evaporating and slowly cool- 
ing ; but the solution is usually at once evaporated to dryness, 
a white pulverulent salt being obtained. The Hypophosphite of 
Potassium (Potassii Hypophosphis, U. S. P.) (KPH202) may be 
obtained in the same way from its hydrate, and many other hvpo- 
phosphites (Mg2PH202,6fl20, Fe2PII202,6II20, etc.) similarly from 
other hydrates, or by double decomposition of the calcium salt and 
carbonates. 
Hypophosphite of sodium (NaPH202,H,0) (Sodii Hypophosphis, 
IT. S. P.) may be made by decomposing solution of hypophosphite of 
calcium by carbonate of sodium, filtering, and evaporating to dryness. 
It is a white, granular, deliquescent substance. 
Ca2PH2Oa + Na2C03 = 2NaPH202 + CaC03. 
When heated, the water is first evolved, then hydrogen and spon- 
taneously inflammable phosphoretted hydrogen, and a mixture of 
pyrophosphate and metaphosphate of sodium remains (Rammels- 
berg). 
5NaPH202 = Na4P207 + NaP03 + 2PH3 + 2II2. 
IJypophosphorous acid, the hydrogen hypophosphite, may be pre- 
pared by decomposing the barium salt wdth sulphuric acid or the 
calcium salt by oxalic acid : hypophosphite of quinine by dissolving 342 
SALTS OF RARER ACIDULOUS RADICALS. 
the alkaloid in hypophosphorous acid, or by decomposing sulphate 
of quinine by hypophosphite of barium. Hypophosphite of Iron 
(Fe26PII202) (Ferri Hypophosphis, U. S. P.) may be obtained by 
dissolving ferric hydrate in cold aqueous hypophosphorous acid and 
evaporating the solution. 
The hypophosphites are often used in medicine in the form of 
syrups (Syriipus Hypophosphiturn, U. S. P., and Syr. Hypophosphit,urn 
cum Ferro, U. S. I\). The term hypophosphite is in allusion to the 
smaller amount (i'mb, Impo, under or deficiency) of oxygen in these 
compounds (R/3P02) than in the phosphites (R3P03), a class of salts 
having again less oxygen in their molecules than exists in those of 
the phosphates (R.,1’0,). The prefix hypo has similar significance 
in such words as hyposulphite and hypochlorite. 
Tests.—To a portion of the above solution of hypophosphite 
of calcium add solution of chloride of barium, chloride of cal- 
cium, or acetate of lead ; in neither case is a precipitate ob- 
tained, whereas soluble phosphates and phosphites yield white 
precipitates of phosphate .or phosphite of barium, calcium, or 
lead. To other portions add solutions of nitrate of silver and 
mercuric chloride; the respective metals are precipitated ashy 
phosphites. To another small portion add zinc and dilute sul- 
phuric acid; hydrogen and phosphoretted hydrogen are evolved 
as from phosphites. To another portion add sufficient oxalic 
acid to remove the calcium; filter; to the solution of hypo- 
phosphorus acid add solution of sulphate of copper, and slowly 
warm the mixture; solid brown cuprous hydride (Cu2II2) is 
precipitated: increase the heat to the boiling-point; hydrogen 
is evolved and metallic copper set free. Heat a small quantity 
of a solid hypophosphite on the end of a spatula in a flame ; it 
splits up into pyrophosphate, a little metaphosphate, hydrogen, 
phosphoretted hydrogen, and, sometimes, water, burning with 
a phosphorescent light—the official hypophosphite of calcium 
yielding about 80 per cent, of residue. 
7(Ca2PIIA) = 3Ca2P207 + Ca2P03 + 6PH3 + H,0 
+ 4H2. 
To an acid solution of hypophosphite add solution of a per- 
manganate. It is instantly decolorized. The same effect fol- 
lows its addition to an acid solution of a phosphite, but not to 
that of an ortho-,meta-, or pyrophosphate. 
IIyposulpiiurous Acid (H2SA) and other* Hyposul- 
phites.—The only hyposulphite of much interest in pharmacy 
is the sodium salt (Sodti Hyposu/phis, U. S. P.) (Na2S20:1,- 
5II20). Hyposulphites may be regarded as thiosulphates 
0- Q, H2S03S). 343 
HYPOSULPHITES. 
Process.—Heat together gently, or set aside in a warm place, 
a mixture of solution of sulphite of sodium (Na2S03) and a 
little powdered sulphur; combination slowly takes place, and 
hyposulphite of sodium is formed. The solution, filtered from 
excess of sulphur, readily yields crystals. (The solution of 
sulphite of sodium may be made by saturating a solution of 
soda with sulphurous acid gas.) 
Use of Hyposulphite of Sodium in Quantitative Analysis.— 
In the British Pharmacopoeia hyposulphite of sodium is given 
as a reagent for the quantitative estimation of free iodine in 
volumetric analysis. To a few drops of iodine-water add cold 
mucilage of starch ; a deep-blue color (starch iodide) is pro- 
duced. To the product add solution of hyposulphite of sodium 
until the blue color just disappears. This absorption of iodine 
is sufficiently definite and delicate to admit of application for 
quantitative purposes. It depends on the combination of the 
iodine with half of the sodium in two molecules of the hypo- 
sulphite, the hyposulphurous radicals of the two molecules 
apparently coalescing to form a new radical, the tetrathionic 
(from riTpaSj te.tras, four, and Ostov, theion, sulphur), tetrathio- 
nate of sodium (Na2S406) and iodide of sodium being formed. 
Sulphur Oxyacids.—It wTill be as well here to give the formulas of 
other oxyacids of sulphur, forming with the four already mentioned 
a series that is as useful as the series of compounds of nitrogen and 
oxygen in illustrating the soundness of Dalton’s atomic theory (p. 50). 
Hydrosulphurous Acid .... II2S02 
Sulphurous Acid II2S03 
Sulphuric Acid II2S04 
Hyposulphurous Acid .... II2S203 
Pithionic Acid II2S206 
Trithionic Acid II2S308 
Tetrathionic Acid II2S406 
Pentathionic Acid H2S506 
Use of 11 Hypo ” in Photography.—The sodium hyposulphite 
is largely used in photography to dissolve chloride, bromide, or 
iodide of silver off plates which have been exposed in the 
camera. Prepare a little chloride of silver by adding a chloride 
(chloride of sodium) to a few drops of solution of nitrate of 
silver. Collect the precipitated chloride on a filter, wash, and 
add a few drops of solution of hyposulphite of sodium ; the 
silver salt is dissolved, solution of double hyposulphite of so- 
dium and silver being formed. The solution of this double hy- 
posulphite has a remarkably sweet taste, sweeter than syrup, 
if the solution is strong. The double hyposulphite of sodium 344 
and gold is employed for giving a pleasant tint to photographic 
prints. 
Test.—To solution of a hyposulphite add a few drops of 
dilute sulphuric or other acid ; hyposulphurous acid is set free, 
hut at once begins to decompose into sulphurous acid, recog- 
nized by its odor, and free sulphur (2H2S203 = 2H2S03 -f S2). 
This reaction constitutes the best test for hyposulphites. An- 
other good test of a soluble simple hyposulphite is its power 
of dissolving chloride of silver with production of a more or 
less sweet solution. 
SALTS OF RARER ACIDULOUS RADICALS. 
588. Give the formula of ferrocyanide of potassium. 
589. What is the supposed constitution of ferrocyanide of potas- 
sium ? 
590. Enumerate the tests for ferrocyanogen. 
591. What are the respective reactions of ferrocyanide of potas- 
sium with strong and weak sulphuric acid ? 
592. Mention and explain a common source of carbonic oxide in 
households. What is the product of its combustion ? 
593. Write equations or diagrams illustrative of the changes 
effected on ferrocyanide of potassium during its conversion into fer- 
ridcyanide. 
594. By what reactions may the presence of a ferridcyanide in a 
solution be demonstrated ? 
595. State the difference between Prussian blue and Turnbull’s 
blue. 
596. Describe the source, mode of preparation, chief use of, and 
test for hydrofluoric acid. 
597. Illustrate by a diagram the preparation and composition of 
hyposulphite of sodium. 
598. Mention the uses and characteristic reactions of hyposulphite 
of sodium. 
599. Give the names and formulas of eight acids, each containing 
hydrogen, sulphur and oxygen. 
QUESTIONS AND EXERCISES. 
Lactic Acid (IICsII5Os) and other Lactates.—Lactic acid 
occurs naturally in willow-bark (Dott). When milk turns sour its 
sugar has become converted into an acid appropriately termed lactic 
(lac, lactis). Other saccharine and amylaceous substances also by 
fermentation yield lactic acid. The hydrogen lactate (lactic acid) 
is official (Acidum Lacticum, IT. S. I\). 
Process.—Lactate of calcium and lactic acid may be pre- 
pared as follows: Mix together eight parts of sugar, one of 
common cheese, three of chalk, and fifty of water, and set 
aside in a warm place (about 80° F.) for two or three weeks; MALATES. 
345 
a mass of small crystals of lactate of calcium results. Remove 
these, recrystallize from hot water, decompose by sulphuric acid, 
avoiding excess, digest in alcohol, filter off the sulphate of calcium, 
evaporate the clear solution to a syrup; this residue is lactic 
acid ; when of sp. gr. 1.212 it contains 75 per cent, of real acid. 
Lactate of Iron ( Ferri Lactas, U. S. P.; Fe2C3H503,3H20) 
may be made by digesting iron filings in warm diluted lactic 
acid (1 acid to 16 water) till effervescence of hydrogen ceases, 
filtering and setting aside to cool and crystallize. The crystals 
are collected, washed with alcohol, and dried. This ferrous 
lactate occurs in greenish-white crystalline crusts or grains, of 
a mild, sweetish, ferruginous taste, soluble in forty-eight parts 
of cold and twelve of boiling water, but insoluble in alcohol. 
Exposed to heat, it- froths up, gives out thick, white, acid 
fumes, and becomes black, sesquioxide of iron being left. If 
it be boiled for fifteen minutes with nitric acid of the specific 
gravity 1.20, a white, granular deposit of mueic acid will oc- 
cur on the cooling of the liquid. 
Tests.—No single reaction of lactic acid is sufficiently dis- 
tinctive to form a test. The crystalline form of the lactate of 
calcium, as seen by the microscope, is characteristic. The 
production of this salt, and the isolation of the syrupy acid 
itself, are the only means, short of quantitative analysis, on 
which reliance can be placed. It is soluble in water, alcohol, 
and ether, but almost insoluble in chloroform. It is only 
slightly colored by cold sulphuric acid. 
A variety of lactic acid has been obtained from the juice of 
fish; it is termed sarcolactic acid (from (rapzos, sarx, 
sarcos, flesh). Unlike lactic acid, it is precipitated by solution 
of sulphate of copper. 
Malic Acid and other Malates (from 
malum, an apple).—The juice of unripe apples, gooseberries, 
currants, rhubarb stalks, strawberries, grapes, etc. contains 
malic acid and malate of potassium. When isolated it oc- 
curs in deliquescent prismatic crystals. 
Tests.—Malate of calcium is soluble in wTater; 
hence the aqueous solution of malic acid or other malate is not 
precipitated by lime-water or chloride of calcium ; but on add- 
ing spirit of wine a Avhite precipitate falls, owing to the insolu- 
bility of the calcium malate in alcohol. Malates are precipi- 
tated by lead-salts ; on warming the malate of lead with acetic 
acid it dissolves, separating out in acicular crystals on cooling. 
If the mixture be heated without acid, the malate of lead 
agglutinates and fuses. 346 
SALTS OF RARER ACIDULOUS RADICALS. 
Hot strong sulphuric acid chars malic acid far less readily than it 
does nearly all other organic acids. 
Asparagin (C41I8N203,H20).—This proximate principle of plants 
occurs in many vegetable juices, and doubtless plays a very import- 
ant part in their nutrition. It is deposited in crystals when the fresh 
juices of asparagus, marshmallow, etc. are rapidly evaporated. It 
is noticed here because malic acid is readily obtained from it by oxi- 
dation, nitrogen being eliminated, and because its exact natural posi- 
tion among chemical substances is not yet well made out. The atoms 
of its molecule are those of aspartate of ammonium (NH4C4II6N04), 
into which it is converted when its solution is long boiled. Decom- 
posed by aid of ferments, asparagin, absorbing hydrogen, yields 
succinate of ammonium (NII4)2C4H404. Such reactions as these and 
the formation of lactic acid from sugars should suggest to the stu- 
dent possible modes in which chemical changes take place in the 
plant-department of the vast laboratory of nature. 
Meconic Actd (HsC7H07).—Opium contains meconic acid 
(from [j.rjxiov, mekon, a poppy) partially combined with morphine. 
To concentrated infusion of opium nearly neutralized by am- 
monia add solution of chloride of calcium; meconate of cal- 
cium is precipitated. Wash the precipitate, place it in a small 
quantity of hot water, and add a little hydrochloric acid; the 
clear liquid (filtered, if necessary) deposits scales of meconic 
acid on cooling. 
Tests.—To solution of meconic acid or other meconate, or 
to infusion of opium, add a neutral solution of ferric chloride; 
a red solution of meconate of iron is produced. To a portion 
of the mixture add solution of corrosive sublimate; the color 
is not destroyed; to another portion add hydrochloric acid; 
the color is discharged. (These reagents act on sulphocyanate 
of iron, which is of similar tint, in exactly the opposite man- 
ner.) To another portion add a drop of a dilute acid and boil; 
the color is not discharged. (A solution of ferric acetate, 
which is of similar color, is decomposed on boiling, giving a 
colorless fluid and a red precipitate of ferric oxyacetate.) 
The normal meconates of potassium, sodium, and ammonium are 
soluble in water, the acid meconates very slightly soluble, the meco- 
nates of barium, calcium, lead, copper, and silver insoluble in water, 
but soluble in acetic acid. 
Metaphosphoric Acid (HP03) and other Metaphos- 
phates.—Prepare phosphoric anhydride (P205) by burning a 
small piece of phosphorus in a porcelain crucible placed on a 
plate and covered by an inverted test-glass tumbler, half-pint 
measure-glass, or some such vessel. After waiting a few 
minutes for the phosphoric anhydride to fall, pour a little 
water on the plate and filter the liquid; the product is solution NTTIUTES. 
347 
of metaphosphoric acid (from /jmet a, a preposition de- 
noting change). 
?A + H,0 = 2HP03. 
Tests.—To solution of metaphosphoric acid add ammonio- 
nitrate of silver, or to a neutral metaphosphate add solution 
of nitrate of silver; a white precipitate (AgP03) is obtained. 
This reaction sufficiently distinguishes metaphosphates from 
the ordinary phosphates or orthophosphates (from oyOds, orthos, 
straight), as the common phosphates may, for distinction, be 
termed (which give, it will be remembered, a yellow precipitate 
with nitrate of silver). Another variety of phosphates shortly 
to be considered, the pyrophosphates, also gives a white precipi- 
tate with nitrate of silver. To the solution of metaphosphoric 
acid obtained as above, or by the action of acetic acid on a 
metaphosphate, add an aqueous solution of white of egg; 
coagulation of the albumen ensues. Neither orthophosphoric 
nor pyrophosphoric acid coagulates albumen. When mixed 
with an equal volume of Tincture of Chloride of Iron, meta- 
and pyrophosphoric acids give a precipitate after some time 
(U. S. P.). Boil tlie aqueous solution of metaphosphoric acid 
for some time; on testing the solution the acid will be found 
to have been converted into orthophosphoric acid:— 
IIP03 + H20 = II3PO4 (orthophosphoric acid). 
The ordinary medicinal phosphoric acid is made from phos- 
phorus and nitric acid, the liquid being evaporated to a syrupy 
consistence to remove the last traces of nitric acid. It may 
contain pyrophosphoric and metaphosphoric acids, if the heat 
employed be high enough to remove the elements of water :— 
2H3P04 — H20 = II4P,07 (pyrophosphoric acid). 
H3PO4 — HjO = HP03 (metaphosphoric acid). 
On redilution the metaphosphoric acid only slowly reabsorbs 
water. If, therefore, on testing, metaphosphoric be found to be 
present, the solution should be boiled until conversion to ortho- 
phosphoric acid has occurred. 
Nitrous Acid (HN02) and other Nitrites.—Strongly 
heat a fragment of nitrate of potassium or of sodium on a 
piece of platinum foil; oxygen is evolved and nitrite of potas- 
sium remains. 
Test.—Dissolve the residue in water, add a few drops of 
dilute sulphuric acid, then a little weak solution of iodide of 
potassium, and, lastly, some mucilage of starch ; the deep-blue 
compound of iodine and starch is at once produced. Repeat 348 
SALTS OF RARER ACIDULOUS RADICALS. 
this experiment, using nitrate of potassium instead of nitrite; 
no blue color is produced. 
Tests for Nitrites in Water.—This liberation of iodine by nitrites 
and not by nitrates is a reaction of considerable value in searching 
for nitrites in ordinary drinking-waters, the occurrence of such salts 
being held to indicate the presence of nitrogenous organic matter in 
a state of oxidation or decay. The sulphuric acid used in the opera- 
tion must be pure, and the iodide of potassium free from iodate. If 
much organic matter is present, however, the nitric acid liberated by 
the sulphuric may be reduced to nitrous acid. It is perhaps best, 
therefore, to add acetic acid, and (Fresenius) distil over 10 or 20 per 
cent, of the water and apply the test to this distillate. Very dilute 
solutions of nitrous acid may thus be distilled without the slightest 
decomposition. 
Commercial Nitrous Acid.—The liquid commonly termed in phar- 
macy “ nitrous acid ” is simply nitric acid impure from the presence 
of nitrous acid. 
The only nitrite used in medicine is a nitrite of an organic basy- 
lous radical, ethyl; nitrite of ethyl (C2II5N02), or nitrous ether, is 
one of the chief constituents of “ sweet spirit of nitre ” (Spiritus 
AEtheris Nitrosi, U. S. P. • vide Index). 
Opiieuic Acid (C13II20O10).—This is one of the principles to which 
the herb Ophelia chirata, or Cliiretta (Chirata, U. S. P.), owes its 
bitterness. It is an amorphous yellow body. Another is Chiratin 
(C26H48015), decomposable by hydrochloric acid into Chiratogenin 
(C13II2403) and ophelic acid (Hohn). 
Phosphorous Acid (II3P03, or II2PII03).—It is necessary to notice 
this compound in order that the reader may have brought before him 
the three acids of phosphorus, namely, phosphoric acid (II3P04), 
phosphorous acid (I12PI103), and hypophosphorous acid (IIPII202): 
it will be noticed that in composition they differ from each other 
simply in the proportion of oxygen, the molecules containing four, 
three, and two atoms respectively. In constitution they differ by 
the hypothetical phosphoric radical or grouping being trivalent, the 
phosphorous bivalent, and the hypophosphorous radical univalent. 
These three acids and corresponding salts must not be confounded 
with pyrophosphoric and metaphosphoric acids and salts •, the 
former are acids of phosphorus; the latter, varieties of phosphoric 
acid •, the former, in composition, differ from each other in the pro- 
portion of oxygen they contain; the latter, by the elements of 
water :— 
2HI + 2II NO* = 2H.;0 + 2NO + I2. 
Acids of Phosphorus. Varieties of Phosphoric Acid. 
II3P04 phosphoric acid. II3P04 (ortho)phosphoric acid. 
H2PH03 phosphorous acid. 1I4P207 pyrophosphoric acid. 
HPH202 hyphosphorous acid. HP03 metaphosphoric acid. 
When hypophosphorous acid is exposed to the air, oxygen is absorbed 
and phosphorous acid results ; by prolonged exposure more oxygen 349 
is absorbed and phosphoric acid is obtained. When phosphoric acid, 
or rather, for distinction, orthophosphoric acid, is heated, every two 
molecules yield the elements and a molecule of water, and pyro- 
phosphoric acid results; by prolonged exposure to heat more water 
is evolved, and metaphosphoric acid is obtained. These differences 
will be further evident if the formulae be written empirically, nearly 
all being doubled, thus :—• 
PYROPHOSPHATES. 
H6P204 hypophosphorous acid. 
H6P206 phosphorous acid. 
h6p208 
phosphoric acid, or 
orthophosphoric acid. 
H4P207 pyrophosphoric acid. 
II2P206 metaphosphoric acid. 
Or thus: 
phosphorous acid 
h6p20. 
phosphoric acid 
h6p208 
pyrophosphoric acid\ 
\ ' II4P207 
/hypophosphorous acid 
h6p204 
metaphosphoric acid\ 
h2p206 
From the central compound, phosphoric acid, the acids of phosphorus 
differ by regularly diminishing proportions of the element oxygen 
(see previous page), the varieties of phosphoric acid by regularly 
diminishing proportions of the elements of water. 
Prepare phosphorus arid by exposing a moist stick of phos- 
phorus to the air; a thin stream of heavy white vapor falls, 
which contains the acid in question. The best method of col- 
lection is to place the stick in an old test-tube having a hole in 
the bottom, to support this tube by a funnel or otherwise, the 
neck of the funnel being supported in a bottle, test-glass, or 
tube, at the bottom of which is a little water. Having collected 
some phosphorous acid in this way, apply the various tests 
already alluded to under Hypophosphorous Acid, first carefully 
neutralizing the phosphorous acid by an alkali. The means by 
which the varieties of phosphoric acid are distinguished have 
been given under Metaphosphoric Acid. Associated with the 
phosphorous acid, prepared as above stated, there is said to be 
an acid having the formula H2P03, and termed hypophosphoric 
acid. Its anhydride would be P204. 
Other soluble phosphites are prepared by neutralizing phos- 
phorous acid with alkalies, and the insoluble phosphites by 
double decomposition. 
Pyrogallic Acid.—See Tannic Acid. 
Pyrophosphoric Acid (II4P207) and other Pyrophos- 
phates.—Heat ordinary phosphate of sodium (Na2IIP04,- 
12H20) in a crucible ; water of crystallization is first evolved, 350 
.SALTS OF RARER ACIDULOUS RADICALS. 
and dry phosphate (Na2HP04) remains. Continue the heat to 
redness ; two molecules of the salt yield one molecule of water, 
and a salt having new properties is obtained :— 
2Na2HP04 - II20 = Na4P207. 
It is termed pyrophosphate of sodium, in allusion to its origin 
(ffvp, pur, fire). From its solution in water it may be obtained in 
prismatic crystals (Na4P207,l(JH20), Sodii Pyrophosphas, U. S. P. 
Phosphoric acid itself is similarly affected by heat, 2II3P04 — II20 
'= II4P207 (pyrophosphoric acid), though metaphosphoric acid is also 
formed. Other pyrophosphates are produced in a similar wray, or by 
double decomposition and precipitation, or by neutralizing pyro- 
phosphoric acid by an oxide, hydrate, or carbonate. Possibly the 
pyrophosphates are only compounds of orthophosphates with meta- 
phosphates :— 
Na4P207 = Na3P04,NaP03. 
Tests.—To solution of a pyrophosphate add solution of nitrate 
of silver; white pyrophosphate of silver (Ag4P207) falls as a 
dense white powder, differing much in appearance from the 
white gelatinous metaphosphate of silver or the yellow ortho- 
phosphate. To pyrophosphoric acid, or to a pyrophosphate 
mixed with acetic acid, add an aqueous solution of albumen 
(white of egg) ; no precipitate occurs. Metaphosphoric acid, it 
will be remembered, gives a white precipitate with albumen. 
600. What arc the sources of lactic acid ? 
601. How is lactic acid usually prepared? 
602. Name some of the plants in which malic acid is found. 
603. Whence is meconic acid derived ? 
604. By what process may meconic acid be isolated ? 
605. Which is the best test for the meconic radical ? 
606. Distinguish meconates from sulphocyanates. 
607. Give the mode of manufacture of hyphophosphites. 
608. How is phosphoretted hydrogen prepared? 
609. By what ready method may metaphosphoric acid be obtained 
for experimental purposes ? 
610. Name the tests for metaphosphates. 
611. How may meta- or pyrophosphoric acid be converted into 
orthophosphoric acid ? 
612. Describe the preparation of phosphorous acid. 
613. State the relations which the acids of phosphorus bear to 
each other. 
614. How are pyrophosphates prepared? 
615. Offer two views of the constitution of pyrophosphates. 
616. Define, by formulae, metaphosphates, pyrophosphates, ortho- 
phosphates, phosphites, and hypophosphites. 
QUESTIONS AND EXERCISES. SILICATES. 
351 
617. Mention the tests by which meta-, pyro-, and orthophosphates 
are analytically distinguished. 
618. Name the reactions by which hypophosphites and phosphites 
are detected. 
Silicic Acid (II4Si04) and other Silicates.—Silicates of various 
kinds are among the commonest of minerals. The various clays 
are aluminium silicates; the volcanic substance termed pumice- 
stone is a porous silicate of aluminium and of alkali-metals or alka- 
line-earth metals ; meerschaum is an acid silicate of magnesium ; the 
ordinary sandstones are chiefly silica; sand, flint, quartz, agate, 
chalcedony, and opal are silicic anhydride or silica (Si02). Tripoli, 
a polishing powder now found in many other countries than Tripoli, 
consists of infusorial skeletons of nearly pure silica. Bath brick, 
used in knife-polishing, is a silico-calcareous deposit found in the 
estuary at Bridgewater and other places. Asbestos or amianth is a 
fibrous silicate of calcium and magnesium, the length of the fibres 
being from less than one inch to five feet. A single silk-like fibre can 
easily be fused, but, even in very small masses, and for all practical 
purposes, asbestos is infusible and, of course, incombustible. It is 
also a bad conductor of heat. It is already largely used in piston- 
rods and joints and for steam apparatus generally; as a covering 
for boilers to prevent loss of heat by radiation; and for so lining 
ceilings, floors, and other partitions as to render rooms, etc. fire- 
proof. Artificial silicates are familiar under the forms of glass and 
earthenware. Common English window-glass is usually silicate of 
calcium, sodium, and aluminium; French glass, silicate of calcium 
and sodium ; Bohemian, chiefly silicate of potassium and calcium ; 
English flint- or crystal-glass for ornamental, table, and optical pur- 
poses is mainly silicate of potassium and lead. Earthenware is 
mostly silicate of aluminum (clay), with more or less of silicate of 
calcium, sodium, and potassium, and, in the commoner forms, sili- 
cates of iron. The various kinds of porcelain (China, Sevres. Meis- 
sen, Berlin, English), Weclgtcood-ware, and stoneware are varieties of 
earthenware. Kaolin or China Clay, which is disintegrated felspar, 
not more common in China than in Devonshire and Cornwall, is the 
clay which yields the finest translucent porcelain. Crucibles, bricks, 
and tiles are clay silicates. Mortar is essentially silicate of calcium. 
Portland, Roman, and other hydraulic cements are silicates of cal- 
cium with more or less silicate of aluminium. 
Mix together a few grains of powdered flint or sand with 
about five or six times its weight of- carbonate of sodium and 
an equal quantity of carbonate of potassium, and fuse a little 
of the mixture on platinum-foil in the blowpipe-flame; the 
product is a kind of soluble glass. Boil the foil in water for 
a few minutes, filter; to a portion add excess of hydrochloric 
acid, evaporate the solution to dryness, and again boil the resi- 
due in water and acid ; oxide of silicon, silicic anhydride, or 
silica (Si02), remains as a light, flaky, insoluble powder. 352 
SALTS OF RARER ACIDULOUS RADICALS. 
The soluble glass or glass liquor of trade commonly contains 10 
or 12 per cent, of soda (NallO) to 20 or 25 per cent, of silica (Si02). 
When of sp. gr. 1.300 to 1.400 it satisfies official requirements 
(jLiquor Sodii Silicatis, U. S. P.). 
The foregoing operation constitutes the test for silicates. By 
fusion with alkali the silicate is decomposed, and a soluble alkaline 
silicate formed. On addition of acid, silicic acid (II4Si04) is set free, 
but remains in solution if sufficient water is present. The heat sub- 
sequently applied eliminates water and reduces the silicic acid to 
silica (Si02), which is insoluble in water or acid. By the addition 
of hydrochloric acid to soluble glass, and removal of the resulting 
alkaline chloride and excess of hydrochloric acid by dialysis (a pro- 
cess to be subsequently described), a pure aqueous solution of silicic 
acid may be obtained; it readily changes into a gelatinous mass of 
silicic acid. Possibly some of the natural crystallized varieties of 
silica may have been obtained from the silica contained in such an 
aqueous solution, nearly all waters yielding a small quantity of 
silica when treated as above described. 
A variety of silicic acid (II2Si03) sometimes termed dibasic, to 
distinguish it from the normal or tetrabasic acid (H4Si04), results 
when the aqueous solution of the latter is evaporated in vacuo. 
Siliciuretted hydrogen, or hydride of silicon (SiII4), is a sponta- 
neously inflammable gas formed on treating silioide of magnesium 
with hydrochloric acid. It is the analogue of light carburetted 
hydrogen (CII4). A liquid chloride of silicon (SiCl4) and a gaseous 
fluoride (SiF4) also exist. Many other analogies are traceable 
between the elements silicon, boron, and carbon (see p. 330). 
Succinic Acid (H2C4II404).—Amber (Succinum) is a peculiar resin 
usually occurring in association with coal and lignite. From the fact 
that fragments of coniferous fruit are frequently found in amber, and 
impressions of bark on its surface, it is considered to have been an 
exudation from a species of Pinus now probably extinct. Heated in 
a retort, amber yields, first, a sour aqueous liquid containing acetic 
acid and another characteristic body appropriately termed succinic 
acid; second, a volatile liquid known as oil of amber (Oleum Suc- 
cinic U. S. P.), resembling the oil yielded by most resinous sub- 
stances under similar circumstances ; and, third, a pitchy residue 
allied to asphalt. The succinic acid is a normal constituent of the 
amber; the acetic acid is produced during distillation. Succinic acid 
has also been found in wormwood, in several pine-resins, and in cer- 
tain animal fluids, such as those of hydatid cysts, and hydrocele. 
It may be obtained artificially from butyric, stearic, or margaric acid 
by oxygen. Tartaric, malic-, and succinic acids are also convertible 
the one into the other. 
The succinates are normal (R/2C4II404) and acid (R/HC4H404); 
a double succinate of potassium and hydrogen (KHC4H404,H2C4H404,- 
H20), analogous to the superacid oxalate, salt of sorrel, also exists. 
Soluble succinates give a bulky brown precipitate with neu- 
tral ferric chloride, only less voluminous than ferric benzoate; 
a white precipitate with acetate of lead, soluble in excess of SULPHOCYANATES. 
353 
either reagent; with nitrate of silver, a white precipitate after 
a time; with chloride of barium, no precipitate at first, but a 
white one of succinate of barium on the addition of ammonia 
and alcohol. Succinates are distinguished from benzoates by 
the last-named reaction, and by not yielding a precipitate on 
the addition of acids (vide p. 334). 
SuLPHOCYANIC ACID (IlCyS) AND OTHER SuLPHOCYAN- 
ates.—Boil together sulphur and solution of cyanide of potas- 
sium ; solution of sulphocyanate of potassium (KCyS) is formed. 
Warm the liquid, add hydrochloric acid till it faintly reddens 
litmus-paper, and filter; any sulphide of potassium is thus de- 
composed, and the solutions may then be used for the follow- 
ing reactions. 
Tests.—Filter, and to a small portion of the solution add a 
ferric salt (Fe2ClB) ; a deep blood-red solution of ferric sulpho- 
cyanate is formed. To a portion of the red liquid add a little 
hydrochloric acid; the color is not discharged (meconate of 
iron, a salt of similar tint, is decomposed by hydrochloric acid). 
In the acid liquid place a fragment or two of zinc ; sulphuretted 
hydrogen is evolved, and the red color disappears. To another 
portion of the ferric sulphocyanate add solution of corrosive 
sublimate; the color is at once discharged. (Ferric meconate 
is unaffected by corrosive sublimate.) The ferric is the best 
test of the presence of a sulphocyanate; indirectly, it is a good 
test of the presence of hydrocyanic acid or cyanogen. Solutions 
of pure ferrous salts are not colored by the solution of sulpho- 
cyanate. Bed ferric acetate is decomposed by ebullition. 
Neither the ferric acetate nor the meconate yields its color 
to ether; but on shaking ferric sulphocyanate solutions with 
ether the latter takes up the salt and becomes of a purple color. 
To solution of a sulphocyanate add solution of mercuric 
nitrate; mercuric sulphocyanate is precipitated as a white 
powder. 
Pharaoh's Serpents.—Mercuric sulphocyanate, thoroughly washed 
and made up into little cones, forms the toy called Pharaoh’s Ser- 
pent. It readily burns when ignited, the chief product being a 
light solid matter (mellon, C9N13, and the melam, c8H6N6), which 
issues from the cone in a snake-like coil of extraordinary length/ 
The other products are mercuric sulphide (of which part remains in 
the snake and part is volatilized), nitrogen, sulphurous, and car- 
bonic acid gases, and vapor of metallic mercury. (For details con- 
cerning the economical manufacture of sulphocyanates, see Phar- 
maceutical Journal, second series, vol. vii. p. 581 and p. 152.) 
The sulphocyanic radical (CyS) is often termed sulphocyanogen 
(Scy), and its compounds regarded as sulphocyanides. Saiiva con- 
tains sulphocyanates. 354 
Tannic Acid, or Tannin (Acidum Tannic urn, U. S. 1\, C14H10O 
9? 
chiefly).—This is a common astringent constituent of plants, but is 
contained in largest quantity in galls (excrescences on the oak 
formed by the puncture and deposited ova of an insect). English 
galls contain from 14 to 28 per cent, of tannic acid ; Aleppo galls 
(Galla, U. S. P.) from 25 to 65 per cent. It is present also in the 
White Oak (Quercus Alba, U. S. P.). 
Process.—“ Expose powdered galls (about an ounce is suffi- 
cient for the purpose of study) to a damp atmosphere for two 
or three days, and afterward add sufficient ether to form a soft 
paste. Let this stand in a well-closed vessel for twenty-four 
hours; then, having quickly enveloped it in a linen cloth, sub- 
mit it to strong pressure so as to separate the liquid portion, 
which contains the hulk of the tannin in solution. Reduce the 
pressed cake to powder, mix it with sufficient ether, to which 
one-sixteenth of its hulk of water has been added, to form 
again a soft paste, and press this as before. Mix the expressed 
liquids, and expose the mixture to spontaneous evaporation 
until, by the aid subsequently of a little heat, it has acquired 
the consistence of a soft extract; then place it on earthen 
plates or dishes and dry it in a hot-air chamber at a tempera- 
ture not exceeding 212°.” 
The resulting tannic acid occurs in pale yellow vesieular 
masses or thin glistening scales, with a strongly astringent 
taste and an acid reaction, readily soluble in water and recti- 
fied spirit, very sparingly soluble in pure ether, though soluble 
in the ethereal fluid used in the foregoing process—a fluid 
Avhich is really a mixture of true ether, water, and alcohol 
(both the latter contained in the common “ ether ”), and a little 
added water also. 
Medicinal Uses.—Tannic acid is very soluble in water, and in this 
form is usually administered in medicine. 
Tests.—To an aqueous solution of tannic acid add aqueous 
solution of gelatine; a yellowish-white flocculent compound of 
the two substances is precipitated. This is a good test of the 
presence of tannic acid. 
Tanning.—The above reaction also serves to explain the chemical 
principle involved in tanning—the operation of converting skin into 
leather. In that process the skin is soaked in infusion of oak-bark 
(Quercus cortex), the tannic acid of which, uniting with the gelati- 
nous tissues of the skin, yields a compound very well represented by 
the above precipitate. The outer bark of the oak contains little or 
no tannic acid, and is commonly shaved off1 from the pieces of bark 
which are large enough to handle •, useless coloring-matter is thus 
also rejected. Other infusions and extracts besides that of oak-bark 
salts of rarer acidulous radicals. 355 
T ANNATES. 
(chiefly catechu, sumach, and valonia) are largely used by tanners: 
if used alone these act too quickly, and give a harsh, hard, less- 
durable leather. The tannic acid of these preparations is probably 
slightly different from that of oak-bark. 
To an aqueous solution of tannic acid add a neutral solution 
of a ferric salt; dark bluish-black tannate of iron is slowly 
precipitated. This is an excellent test for the presence of tan- 
nic acid in vegetable infusions. The precipitate is the basis of 
nearly all black writing-inks. Ferrous salts give at first only 
a slight reaction with tannic acid; but the liquid gradually 
darkens. Characters written with this liquid become quite 
black in a few hours, and are very permanent. 
To an aqueous solution of tannic acid add solution of tartar- 
emetic ; tannate of antimony is precipitated. This reaction and 
that with gelatin are useful in the quantitative estimation of 
the amount of tannic acid in various substances. 
Tannic acid as it occurs in oak-bark is said to be a glucoside, that 
is, like several other substances, yields glucose (grape-sugar) when 
boiled with dilute sulphuric or hydrochloric acid, the other product 
being gallic acid. 
Catechu, Gambier, or Terra Japonica, an extract of the Uncaria 
Gambler; as well as the true Catechu, Catch, or Terra Japonica, an 
extract from the Acacia catechu (Catechu, U. S. P.; Catechu nigrum, 
P. I.) and A. Suma; East Indian Kino (Kino, U. S. P.) from the 
Pterocarpus marsupium ; also Bengal or Butea Kino, from the Palas 
or Dhak tree, Butea frondosa (Butece gummi vel Kino Bengalensis, 
P. I.); Elm-bark (Ulmi Cortex, B. P.); and some other vegetable 
products, contain a variety of tannic acid (mimotannic acid), which 
gives a greenish precipitate with neutral solutions of ferric salts. 
According to Paul and Kingzett it yields, when decomposed, unfor- 
mentable sugar, and an acid different from ordinary gallic acid. 
Catechu and Gambier also contain catechuic acid or catechin, 
C13H1205, a body occurring in minute colorless acicular crystals, 
and, like mimotannic acid, affording a green precipitate with ferric 
salts. 
Bael fruit (Belas Fructus, B. P.), from the JEgle Marmelos, is said 
to owe its power as a remedy for dysentery and diarrhoea to a variety 
of tannic acid, but this is questionable. About 10 per cent, of tannic 
acid is contained in the leaves of Castanea vesca (Castanea, U. S. P.), 
the tree yielding the common edible Spanish chestnuts. The rind 
of the fruit of the pomegranate (Punica granatum) (Granati Cortex, 
P. I.) contains tannic acid. The astringency of Pomegranate-root 
Bark (Granatum, U. S. P.) is due to a tannic acid (its anthelmintic 
properties probably to a resinoid matter or possibly to what Tanret 
states to be a liquid alkaloid, pellitierine, ClfiII30N2O2). A tannic 
acid also probably gives the astringency to Logwood (Htematoxglon, 
U. S. P.), the color of which is due to oxidized hcematoxglin. Rha- 
tany-rooi bark (Krameria, IJ, S, P.) contains about 20 per cent, of 356 
SALTS OF RARER ACIDULOUS RADICALS. 
tannic acid, its active astringent principle ; rhubarb-root, about 9 
per cent. Bearberiy-leaves (Uva Ur si, U. S. P.) owe most of their 
therapeutic power to about 35 per cent, of tannic acid. (The cause 
of their influence on the kidneys is not yet traced.) They also con- 
tain arbutin, a crystalline glucoside. Larch-bark (Laricis Cortex, 
B. 1\), the inner bark of Pinus larix or Larix europcea, contains, 
according to Stenhouse, a considerable amount of a tannic acid 
giving olive-green precipitates with salts of iron, and larixin and 
iarixinic acid (C10l l10O5), a somewhat bitter substance. Areca nuts 
or Betel nuts (Areca, B. P.), from the Areca Palm (Areca catechu), 
contain, according to Fliickiger and Ilanbury, about 15 per cent, 
of “ tannic matter.” The extract of the fruit of Gab, or Diospyros 
embryopteris (Diospyri Fructus, P. I.), is a powerful astringent con- 
taining tannic acid. The rhizome (Geranium, U. S. P.) of Geranium, 
maculatum, Spotted Cranesbill or Arum-root, contains both tannic 
and gallic acids. Sumac or Shumac, or Sumach, the leaves and 
stalks of various species of Rhus, chiefly Rhus coriaria, contains 
ordinary tannic acid and gallic acid. The fruit of sumach (Rhus 
glabra■, U. S. P.) contains tannic and much malic acid. The bark of 
Prinos verticillatus, the Black Alder or Winterberry (Prinos, U. S. P.), 
contains tannin and a bitter principle. The princijail constituent of 
the bark of the root of Rubus villas us, or high blackberry, and of R. 
canadensis and R. trivialis (Rubus, U. S. P.), is tannic acid. 
Gallic Acid (H,C7H305,H20) (Acidum Gallicum, U. S. P.) 
occurs io small quantity in oak-galls and other vegetable sub- 
stances, but is always prepared from tannic acid. Powdered 
galls are moistened with water and set aside in a warm place 
for five or six weeks, or until a little treated with water and 
filtered yields a solution which is only slightly precipitated 
with solution of isinglass, occasionally being remoistened; fer- 
mentation occurs, and impure gallic acid is formed. The prod- 
uct is treated with about three times its weight of water, 
boiled to dissolve the gallic acid, filtered, the solution set aside 
to cool, deposited gallic acid collected, drained, pressed between 
folds of paper to remove all mother-liquor, and, if necessary, 
purified by recrystallization from water, or by solution in hot 
water with animal charcoal, which absorbs coloring-matter. 
On filtering and cooling, most of the acid separates in the form 
of fawn-colored, slender acicular crystals. Gallic acid is soluble 
in about 100 times its weight of cold or 3 of boiling water, 
freely in spirit, sparingly in ether, also in glycerin. 
The nature of the action by which gallic acid is thus produced is 
probably similar to that of the action of dilute acids on tannic acid. 
During the process oxygen is absorbed and carbonic acid gas 
evolved, the sugar being thus broken up or perhaps prevented 
from being formed. 
Test,—To an aqueous solution of gallic acid add a neutral 357 
URATES. 
solution of ferric salt; a bluish-black precipitate of gallate of 
iron falls, similar in appearance to tannate of iron. Ferrous 
salts are also blackened by gallic acid. To more of the solu- 
tion add an aqueous solution of gelatin ; no precipitate occurs. 
By the latter test gallic acid is distinguished from tannic acid. 
Pyrogallic Acid or Pyrogallol (C6II603).—This substance sublimes 
in light feathery crystals when gallic acid is heated. Or it may be 
formed by heating gallic acid w ith 3 or 4 times its weight of glycerin 
to 190° or 200° C. for a short time until carbonic acid gas ceases to be 
evolved. Longer heating at a lower temperature is not equally effec- 
tive, and below 100° C. probably no pyrogallol is produced (Thorpe). 
To an aqueous solution add a neutral solution of a ferric salt, a red 
color is produced. To another portion add a ferrous salt; a deep- 
blue color results. 
Test for the Three Acids.—To three separate small quantities of 
milk of lime in test-tubes add, respectively, tannic, gallic, and pyro- 
gallic acids; the first slowly turns brown, the second more rapidly, 
w hile the pyrogallic mixture at once assumes a beautiful purplish- 
red color, changing to brow n. These reactions are highly character- 
istic. They are accompanied by absorption of oxygen from the air. 
Use of Pyrogallic Acid in Gas-analysis.—A mixture of pyrogallic 
acid aftd solution of potash absorbs oxygen with such rapidity and 
completeness that a strong solution of each, passed up successively 
by a pipette into a graduated tube containing air or other gas, forms 
an excellent means of estimating free oxygen. The value of this 
method may be roughly proved by pouring a small quantity of each 
solution into a phial, immediately and firmly closing its mouth with 
a cork, thoroughly shaking the mixture, and then removing the cork 
under wTatcr; the water rushes in and occupies about one-fifth of the 
previous volume of air, indicating that the atmosphere contains one- 
fifth of its bulk of oxygen. The small amount of carbonic acid gas 
present in the air is also absorbed by the alkaline liquid; in delicate 
experiments this should be removed by the alkali before the addition 
of pyrogallic acid. 
Toxicodendric Acid is the volatile, excessively acrid and poisonous 
principle of the Poison Oak or Poison Ivy, the fresh leaves of which 
are official (Rhus toxicodendron, U. S. P.), Maisch. 
Uric x\cid (H.2Cr)H.jN403) and other Urates.—Acidulate 
a few ounces of human urine with hydrochloric acid, and set 
aside for twenty-four hours ; a few minute crystals of uric acid 
will be found adhering to the sides and bottom of the vessel 
and floating on the surface of the liquid. 
Microscopical Test.—Remove some of the floating particles 
by a slip of glass, and examine by a powerful lens or micro- 
scope ; the chief portion will be found to be in yellowish semi- 
transparent crystals, more or less square, two of the sides of 
which are even, and two very jagged; but other forms are 358 
SALTS OF RARER ACIDULOUS RADICALS. 
common (see the lithographs in the section on Urinary Sedi- 
ments.) 
Chemical Test.—Collect more of the deposit, place in a watch- 
glass or small white evaporating-dish, remove adherent moisture 
by a piece of blotting- or filter-paper, add a drop or two of 
strong nitric acid, and evaporate to dryness; the residue will 
be red. When the dish is cold add a drop of solution of am- 
monia ; a purplish-crimson color results. The color is deepened 
on the addition of a drop of solution of potash. 
Notes.—Uric acid (or lithic acid) and urates (or lithates) of sodium, 
potassium, calcium, and ammonium are common constituents of an- 
imal excretions. Human urine contains about one part of urate 
(usually urate of sodium) in 1000. When more than this is present 
the urate is often deposited as a sediment in the excreted urino, 
either at once or after standing a short time. Uric acid or other 
urate is also occasionally deposited before leaving the bladder, and, 
slowly accumulating there, forms a common variety of urinary cal- 
culus. Some urates are not definitely crystalline; but when 
treated with dilute nitric acid or a drop of solution of potash, and 
then a drop or two of acetic acid, jagged microscopic crystals of 
uric acid are usually formed.—All urates yield the crimson color 
when treated as above described. This color is due to a definite 
substance murexid (C8H8N606) (from the murex7 a shell-fish of 
similar tint); and the test is known as the murexid test. The 
formation of murexid is due to the action of ammonia on alloxan 
(C4II2N204,41I20) and other white crystalline products of the oxida- 
tion of uric acid by nitric acid. Murexid is a good dye; it may be 
prepared from guano (the excrement of sea-fowl), which contains a 
large quantity of urate of ammonium. The excrement of the ser- 
pent is almost pure ammonium urate. 
Uric acid and the urates will be again alluded to in connection 
with the subject of morbid urine. 
Valerianic Acid or Valeric Acid (HC5H902) and 
other Valerianates.—In a test-tube place a few drops of 
amylic alcohol (fusel oil) with a little dilute sulphuric acid 
and a grain or two of red chromate of potassium, cork the tube, 
set aside for a few hours, and then heat the mixture ; valerianic 
acid, of characteristic valerian-like odor, is evolved. 
Valerianic acid occurs naturally in valerian-root in association 
with the essential oil from which it is derived (vide Index), but is 
usually prepared artificially, by the foregoing process, from amylic 
alcohol, to which it bears the same relation as acetic acid docs to 
common alcohol:— 
C2H5IIO + 03 = HC.11,0. + ILO 
C5HnH0 + 02 = HC5H902 + H20. 
Valerianate of Sodium (NaC5H902) is prepared from the va- 359 
lerianic acid and valerianate of amyl obtained on distilling the 
mixture of amylic alcohol (4 fl. oz.), sulphuric acid (6£ fi. oz. 
with 10 of water), and red chromate of potassium (9 oz. in 70 
of water). The mixture should stand for several hours before 
heat is applied. 
VALERIANATES. 
2(K2CrO«,CrOs) + 8II2S04 = 2(K2S04,Cr23S04) + 8H20 + 302 
Ked chromate of 
potassium. 
Sulphuric 
acid. 
Sulphate of potassium 
and chromium 
(Chrome alum). 
Water. 
Oxy- 
gen. 
c5huho + o2 = hc5ii9o2 + h2o 
Amylic 
alcohol. 
Oxygen. 
Valerianic 
acid. 
Water. 
Amylic 
alcohol. 
2C5HuHO + 02 = C5HnC5H902 + 2H20 
Oxygen. 
Valerianate 
of amyl. 
Water. 
The distillate (TO or 80 oz.) is saturated with soda, which not 
only yields valerianate of sodium with the free valerianic acid, but 
decomposes the valerianate of amyl produced at the same time, more 
valerianate of sodium being formed and some amylic alcohol set 
free, according to the following equations:— 
IIC5H90, + NallO = NaCjHgOj + II20 
C JIuC5H902 + NallO = NaC5II902 + C5IInIIO 
Valerianic. 
acid. 
Soda. 
Valerianate 
of sodium. 
Water. 
Valerianate 
of amyl. 
Soda. 
Valerianate 
of sodium. 
Amylic 
alcohol. 
From the solution of valerianate of sodium (which should be 
made neutral to test-paper by careful addition of soda solution) 
the solid white salt is obtained by evaporation to dryness and 
cautious fusion of the residue. The mass obtained on cooling 
should be broken up and kept in a well-closed bottle. It is 
entirely soluble in spirit. 
Other Valerianates, as valerianate of zinc (Zinci Valerian as, 
U. S. P.) and ferric valerianate (Ferri Valerianas, U. S. P.; 
Fe26C6H902), may be made by double decomposition of vale- 
rianate of sodium with the sulphate or other salt of the metal 
the valerianate of which is desired, the new valerianate either 
precipitating or crystallizing out. A hot solution of sulphate 
of zinc (51 parts) and valerianate of sodium (5 parts) in water 
(40 parts) gives a crop of crystals of valerianate of zinc on 
cooling. 
Tests.—Heated with diluted sulphuric acid, valerianates of 
the metals give valerianic acid, which has a highly character- 
istic smell. Valerianate of sodium thus treated, and the result- 
ing oily acid liquid purified by agitation with sulphuric acid 
and distillation, furnishes valerianic acid. Dry ammonia gas SALTS OF RARER ACIDULOUS RADICALS. 
passed into valerianic acid gives white lamellar crystals of 
valerianate of ammonium (Ammonii Valerianas, TJ. S. P.). 
The amylic alcohol (C6IInIIO) from which valerianates are pre- 
pared may contain the next lower homologue, butylic alcohol 
(C4II9I10). This, during oxidation, will be converted into buty- 
ric acid (IIC41I702), the next lower homologue of valerianic acid 
(IIC3II902), and hence the various valerianates be contaminated by 
some butyrates. These are detected by distillation with diluted sul- 
phuric acid and addition of solution of acetate of copper to the dis- 
tillate, which at once becomes turbid if butyric acid be present. In 
this reaction valerianic and butyric acids are produced by double 
decomposition of the valerianate and butyrate by the sulphuric acid, 
and distil over on the application of heat. On the addition of ace- 
tate of copper (Cu2C21I302) butyrate of copper (Cu2C4II702,II20) is 
formed, and, being almost insoluble in water, is at once precipitated, 
or remains suspended, giving a bluish-white opalescent liquid. Va- 
lerianate of copper (Cu2C511902) is also formed after some time, but 
is far more soluble than the butyrate, and only slowly collects in 
the form of greenish oily drops, which gradually pass into green- 
ish-blue hydrous crystalline valerianate of copper (Larocque and 
Huralt). 
Vanillic Acid (IICgII703) or Vanillin (CgII8Og) or Metiiylpro- 
tocatechuic Aldehyd (07I15CII303), the body to which is due the 
odor and flavor of Vanilla.—The white crystals commonly found on 
vanilla—the prepared unripe pods of Vanilla plant folia—previously 
termed vanillin, were found by Carles to be a weak acid. It occurs 
in vanilla to the extent of from 1| to 3 per cent. Vanillin has 
recently been prepared artificially by Tiemann and Haarmann from 
coniferin, a glucoside existing in the sap wood of pines. The body 
remaining after the removal of glucose from coniferin, or, indeed, 
coniferin itself, by action of a mixture of red chromate of potas- 
sium and sulphuric acid, yields the vanillin. It also may be ob- 
tained by a series of reactions starting from that of carbonic acid 
on carbolate of potassium ; also from the eugenol of oil of cloves. 
By action of hydrochloric acid, vanillin yields chloride of methyl 
and protoeatechuic aldehyd. Such reactions will be better under- 
stood when the pupil has studied succeeding sections on what is 
commonly termed Organic Chemistry. Artificial vanillin is less 
stable than natural vanillin, perhaps because with the latter is asso- 
ciated a preservative resin. 
619. What is the constitution of nitrites? 
620. Mention a test for nitrites in potable waters.- 
621. Which nitrite is official ? 
622. Give the names of some natural and artificial silicates. 
623. What is “ soluble glass ” ? 
624. Distinguish between silica and silicic acid. 
QUESTIONS AND EXERCISES. 361 
DETECTION OF ACIDULOUS RADICALS. 
625. llow are silicates detected ? 
626. What is the quantivalence of silicon? 
627. Mention the sources, formulae, and analytical reactions of 
succinates. 
628. State the mode of manufacture and tests of sulphocyanates. 
629. What proportion of tannic acid is contained in galls? 
630. Describe a process for the preparation of Tannic Acid? 
631. Explain the chemistry of “ tanning.” 
632. Enumerate the tests of tannic acid. 
633. What is the assumed constitution of tannic acid? 
634. Mention official substances other than galls whose astrin- 
gency is due to tannic acid. 
635. IIow is gallic acid prepared ? 
636. By what reaction is gallic distinguished from tannic acid ? 
637. Mention the characteristic properties of pyrogallic acid. 
638. Explain the murexid test for uric acid. 
639. Describe the artificial preparation of valerianic acid and 
other valerianates, giving diagrams or equations. 
640. What is the formula of valerianic acid? 
641. IIow are butyrates detected in presence of valerianates? 
DETECTION OF THE ACIDULOUS RADICALS OF 
SALTS SOLUBLE IN WATER. 
Analytical operations may now be resumed, the detection of acid- 
ulous radicals being practised for two or three days, and then full 
analyses made, both for basylous and acidulous radicals. To this 
end a few compounds of stated metals (potassium, sodium, or am- 
monium) should be placed in the hands of the practical student for 
examination according to the following paragraphs and Tables. 
Mixtures in which both basylous and acidulous radicals may be 
sought should then be analyzed. 
In examining salts soluble in water, and concerning which no 
general information is obtainable, search must first be made for any 
basylous radicals by the appropriate methods {vide page 219 or 255). 
Certain metals having been thus detected, a little reflection on the 
character of their salts will at once indicate what acidulous radicals 
may be, and what cannot be, present. Thus, for instance, if the 
substance under examination is freely soluble in water, and lead is 
found, only the nitric and acetic radicals need be sought, none other 
of the lead salts than nitrate or acetate being freely soluble in 
water. Moreover, the salt is more likely to be acetate than nitrate 
of lead, for two reasons: the former is more soluble than the latter, 
and is by far the commoner salt of the two. Medical and phar- 
maceutical students have probably, in dispensing, already learned 
much concerning the solubility of salts, and whether a salt is rarely 
employed or in common use. And although but little dependence 
can be placed on the chances of a salt being present or absent 
according to its rarity, still the point may have its proper weight. 
If, in a mixture of salts, ammonium, potassium, and magnesium 362 
DETECTION OF ACIDULOUS RADICALS. 
have been found associated with the sulphuric, nitric, and hydro- 
chloric radicals, and we are asked how we suppose these bodies may 
exist in the mixture, it is far more in accordance with common sense 
to suggest that sal-ammoniac, nitre, and Epsom salt were originally 
mixed together than to suppose any other possible combination. 
Such appeals to experience regarding the solubility or rarity of salts 
cannot be made by any one not previously acquainted, or insuf- 
ficiently acquainted, with the characters of salts: in such cases the 
relation of a salt to water and acids can be ascertained by referring 
to the following Table (p. 363) of the solubility or insolubility of 
about five hundred of the common or rarer salts met with in chem- 
ical operations. 
The opposite course to the above (namely, to ascertain what acid- 
ulous radicals are present in a mixture, and then to appeal to ex- 
perience to tell what basylous radicals may be and what cannot be 
present) is impracticable; for acidulous radicals cannot be separated 
out, one after the other, from one and the same quantity of substance 
by a similar treatment to that already given for basylous radicals. 
Indeed, such a sifting of acidulous radicals could scarcely be accom- 
plished at all, or only by a vast deal of labor. The basylous radicals 
must, therefore, be first detected. 
Even when the basylous radicals have been found, the acidulous 
radicals which may be present must be sought for singly, the only 
additional aid which can be brought in being the action of sulphuric 
acid, a barium salt, a calcium salt, nitrate of silver, and ferric chlo- 
ride on separate small portions of the solution under examination, 
as detailed in the second of the following Tables. 
Commence the analysis of an aqueous solution of a salt or 
salts, the basylous radicals in which are known, by writing out 
a list of the acidulous radicals wThich may be, or, if more con- 
venient, of those which cannot be, present. To this end consult 
the following Table (p. 363) of the solubility of salts in water. 
Look for the name of the metal of the salt in the vertical 
column; the letters S and I indicate wdiich salts are soluble 
and which insoluble in water, an asterisk attached to the S 
meaning that the salt is slightly soluble. The acidulous part 
of the name is given in the top line of the Table. All the 
names are in alphabetical order, for facility of reference. 
Some of the salts marked as insoluble in water are soluble in 
aqueous solutions of soluble sa’ts, a few forming soluble double salts. 
To characterize salts as soluble, slightly soluble, or insoluble only 
roughly indicates their relation to water; on the one hand, very fewr 
salts are absolutely insoluble in water; on the other, there is a limit 
to the solubility of every salt. 
If only one, two, or perhaps three, given acidulous radicals can 
he in the liquid, test directly for it or them according to the re- 
actions given in the previous pages. . If several may he present, DETECTION OF ACIDULOUS RADICALS. 
Acetate. 
Arseniate. 
Arsenite. [ 
i Carbonate, j 
Chloride. 
Citrate. 
Chromate. 
Cyanide. 
Hydrate. 
Iodide. 
Nitrate. 
Oxalate. 
Oxide. 
Phosphate. 
Sulphate. 
Sulphide. 
Sulphite.. 
Tartrate. 
Aluminium 
s 
I 
I 
1 
S 
S';; 
I 
? 
• I 
? 
s 
I 
I 
I 
8 
I 
I 
s 
Ammonium 
s 
s 
S 
S 
s 
s 
s 
S 
S 
s 
s 
s 
? 
8 
8 
S 
8 
8 
Antimony 
s 
I 
I 
? 
s 
? 
I 
? 
1 
I 
? 
8* 
1 
I 
I 
I 
I 
I 
Barium 
s 
1 
I 
I 
s 
s* 
I 
s 
s 
s 
s 
I 
8 
1 
I 
s 
I 
I 
Bismuth 
s 
I 
? 
I 
s 
s* 
I 
? 
I 
I 
s 
1 
I 
I 
s 
I 
I 
I 
Cadmium 
s 
? 
? 
1 
s 
s* 
? 
? 
I 
s 
s 
I 
I 
I 
8 
I 
s 
S* 
Calcium 
s 
I 
I 
I 
s 
s* 
s 
s 
s* 
s 
s 
I 
8* 
I 
S* 
s* 
s* 
S* 
Chromium 
s 
I 
? 
I 
s 
s 
I 
I 
I 
s 
s 
S 
I 
I 
s 
I 
s 
s 
Cobalt 
s 
I 
I 
I 
s 
s 
? 
I 
I 
s 
s 
I 
I 
I 
S 
I 
8* 
s 
Copper 
s 
I 
I 
I 
s 
s 
s 
1 
I 
s 
I 
I 
I 
8 
I 
I 
8* 
Ferric 
s 
I 
I 
? 
s 
s 
s 
? 
I 
s 
s 
s* 
I 
I 
S 
I 
? 
s 
Ferrous 
s 
1 
I 
I 
s 
s 
? 
1 
I 
s 
s 
8* 
I 
I 
S 
I 
8* 
s* 
Gold 
? 
I 
? 
? 
s 
? 
? 
I 
I 
I 
? 
? 
I 
I 
? 
I 
? 
? 
Lead 
s 
I 
I 
I 
s* 
s* 
I 
1 
s* 
s* 
s 
1 
I 
1 
I 
I 
I 
I 
Magnesium 
s 
I 
I 
1 
s 
s 
s 
? 
I 
s 
s 
I 
1 
I 
8 
? 
8 
s 
Manganese 
s 
I 
? 
I 
s 
I 
s 
I 
I 
s 
s 
I 
I 
I 
s 
1 
S'* 
s* 
Mercuric 
s 
I 
I 
I 
s 
? 
s* 
s 
I 
I 
s 
I 
I 
I 
8 
f 
? 
I 
Mercurous 
s* 
I 
I 
I 
I 
1 
I 
? 
? 
I 
s 
I 
I 
I 
S* 
l 
V 
I 
Nickel 
s 
I 
1 
I 
s 
s 
I 
I 
I 
s 
s 
I 
I 
I 
s 
1 
s* 
s* 
Platinum 
? 
I 
? 
? 
s 
? 
? 
? 
I 
s* 
s 
? 
I 
? 
S 
I 
s 
? 
Potassium 
s 
s 
S 
s 
s 
s 
s 
s 
s 
s 
s 
s 
S 
8 
8 
s 
8 
s 
Silver 
s* 
I 
I 
I 
I 
I 
I 
I 
? 
I 
s 
I 
I 
I 
S* 
I 
1 
I 
Sodium 
s 
s 
s 
s 
s 
s 
s 
8 
s 
s 
8 
s 
s 
S 
s 
s 
8 
s 
Stannic 
s 
? 
I 
? 
s 
? 
I 
? 
l 
s 
s 
s 
I 
I 
8 
I 
? 
? 
Stannous 
s 
I 
I 
? 
s 
? 
I 
? 
I 
s 
s 
I 
I 
I 
8 
I 
I 
s 
Strontium 
s 
I 
I 
I 
8 
I 
I 
s 
s 
s 
8 
I 
s 
1 
T 
s 
I 
8* 
Zinc 
s 
I 
? 
I 
s 
8* 
s 
I 
? 
s 
s 
I 
I 
I 
8 
I 
S* 
8* 
TABLE OF THE SOLUBILITY OR INSOLUBILITY OF SALTS IN WATER. DETECTION OF ACIDULOUS RADICALS. 
TABLE TO AID IN THE DETECTION OF CHLORIDES, BROMIDES, IODIDES, CYANIDES, NITRATES, CHLORATES, 
BORATES, ACETATES, SULPHIDES, SULPHITES, SULPHATES, CARBONATES, OXALATES, TARTRATES, 
PHOSPHATES, AND CITRATES, IN A NEUTRAL AQUEOUS SOLUTION. 
(For remarks concerning this Table see next page.) 
Sulphuric Acid 
decomposes 
Chloride of Barium 
precipitates 
Chloride of Calcium 
precipitates 
Nitrate of Silver 
precipitates 
Ferric Chloride 
precipitates 
Not pre- 
cipitated. 
Sulphides. 
Sulphites. 
Carbonates, 
with effervescence— 
hydrosulphuric and 
sulphurous acid gases, 
known by smell and 
carbonic acid gas, 
which has no special 
odor, being evolved. 
Cyanides, 
with production of 
the odor of hydro- 
cyanic acid. 
Acetates, 
with production of 
the odor of acetic aciu 
when the solution i. 
warmed. 
Borates. 
Sulphites. 
Sulphates. 
Carbonates.* 
Oxalates. 
Tartrates. 
Phosphates. 
Citrates. 
Of these white barium 
precipitates, the sul- 
phate is the only one 
insoluble in hydro- 
chloric acid; the tar- 
trate and citrate char 
when heated on plat- 
inum foil; the sul- 
phite and carbonate 
are decomposed with 
effervescence by acids. 
Borates. Oxalates. 
Sulphites. Tartrates. 
Sulphates. Phosphates. 
Carbonates. Citrates. 
Of these white calcium 
precipitates, the sul- 
phate only is sol. in 
much water; the bo- 
rate, carbonate, and 
citrate are sol. i u solu- 
tion of chlorideof am- 
monium: all are sol. 
in acetic acid except 
oxalate and some tar- 
trate and sulphate; 
all are sol. in hydro- 
chloric acid, much 
sulphate excepted; 
the dry tartrate and 
citrate char when 
heated; the sulphite 
and carbonate effer- 
vesce with acids. 
Chlorides, white. 
Bromides, white. 
Iodides, yellow. 
Cyanides, white. 
Borates, white. 
Sulphides, black. 
Sulphates, white. 
Carbonates, white. 
Oxalates, white. 
Tartrates, white. 
Phosphates, yellow. 
Citrates, white. 
Of these silver precipi- 
tates, the chloride, 
bromide, iodide, cya- 
nide, and sulphide 
are insoluble in di- 
lute nitric acid; the 
rest soluble. 
Borates, yellowish. 
Sulphides, black. 
Carbonates, reddish. 
Oxalates, yellow. 
Phosphates, yel.-white. 
Gives red color with 
acetates, if neutral. 
Nitrates. ! 
Chlorates. 
Apply spe- 
cial tests. 
Note.—The student should practise the examination of aqueous solutions of salts until able to detect acidulous radicals with facility and 
precision. For this purpose he may finish the analyses of salts or solutions already examined for common and rarer metals, or have aqueous 
solutions of salts, or the salts themselves, specially prepared for present use, the metals of the salts being stated. He will then be in a position 
to effectively study the analysis of salts which may or may not be soluble in water, examining them for both basylous and acidulous radicals. 
* Bicarbonates are not precipitated by Chloride of Barium in the cold. DETECTION OF ACIDULOUS RADICALS. 
pour small portions of the solutions, rendered neutral if necessary 
by ammonia, into five test-tubes, and add, respectively sulphuric 
acid, nitrate or chloride of barium, chloride of calcium, nitrate 
of silver, and ferric chloride ; then consult the Table on page 364, 
in order to correctly interpret the effects these reagents may have 
produced. 
The first point of value to be noticed in connection with this Table 
is one of a negative character ; namely, if either of the reagents 
gives no reaction, it is self-evident that the salts which it decomposes 
with production of a precipitate must be absent. Then, again, if the 
action of one of the reagents indicates the absence of certain acid- 
ulous radicals, those radicals cannot be precipitated by the other re- 
agents ; thus, if the action of sulphuric acid points to the absence 
of sulphides, sulphites, carbonates, cyanides, and acetates, these salts 
may be struck out of the other lists, and the examination of subse- 
quent precipitates be so far simplified. Or, if the barium precipitate 
is soluble in hydrochloric acid and the calcium precipitate in acetic 
acid, neither sulphates nor oxalates can be present. Observing these 
and other points of difference, which will be seen on careful and 
thoughtful reflection, and remembering the facts suggested by a 
knowledge of what basylous radicals are present, one acidulous rad- 
ical after the other may be struck off' as absent or present, leaving 
only one or two as the objects of special experiment. Among the 
chief difficulties to be encountered will be the separation from each 
other of chlorides, bromides, iodides, and cyanides, or of tartrates 
from citrates, and confirmatory tests of the presence of certain com- 
pounds. These may all be surmounted on referring back to the 
reactions of the various radicals, as described under their hydrogen 
salts, the acids. 
In rendering a solution neutral for the application of the various 
group-tests, the employment of any large amount of acid or of alkali 
must be noted ; the presence of actual alkalies (that is, hydrates) or 
of acids, respectively, being thereby indicated. 
Sulphuric acid, the first group-test, may itself yield, especially 
when heated with some solid substances, sulphurous acid or hydro- 
sulphuric acid (see pp. 303 and 308); hence the production of the 
latter acids from a diluted solution only is evidence of the presence 
of a sulphide or sulphite. 
In the precipitate produced by chloride of barium, the second 
group-test, the oxalic radical may be specially sought by the test 
described in the “note” on p. 314. 
Chloride of calcium does not precipitate citrates readily or com- 
pletely in the cold; therefore the mixture should be filtered and the 
filtrate boiled ; calcium citrate then falls. Calcium tartrate is soluble 
in solution of chloride of ammonium when quite freshly precipitated, 
but not after it has become crystalline. From their solution in 
chloride of ammonium, tartrate of calcium is mostly precipitated 
by ammonia, and citrate on boiling. 
The rarer acidulous radicals will very seldom be met with. Ben- 
REMARKS ON THE PRECEDING TABLE. DETECTION OB' ACIDULOUS RADICALS. 
zoates, hippurates (which give benzoic acid), hypochlorites, hyposul- 
phites, nitrites, and valerianates show themselves under the sulphuric 
treatment. Ferrocyaaides, ferridcyanides, meconates, succinates, 
sulphocyanates, tannates, and gallates appear among the salts whose 
presence is indicated by ferric chloride; formiates, hypophospkites, 
malates, and others by nitrate of silver. Urates char when heated, 
giving an odor resembling that of burnt feathers. 
In actual practice the analyst nearly always has some clue to the 
nature of rarer substances placed in his hands. 
If chromium and arsenicum have been detected among the basy- 
lous radicals, those elements may be present in the form of chromates, 
arseniates, and arsenites, yielding with chloride of barium yellow 
chromate of barium and white arseniate and arsenite of barium, and 
with nitrate of silver, red chromate, brown arseniate, and yellow 
arsenite of silver. 
642. In analyzing an aqueous solution of salts, for which radicals 
would you first search, the basylous or the acidulous? and why? 
643. In an aqueous solution there have been found magnesium 
(Mg) and potassium (K), with the sulphuric radical (S04) and iodine 
(I) ; state the nature of the salts which were originally dissolved in 
the water, and mention the principles which guide you in the con- 
clusions. 
644. Give a sketch of the method by which to analyze a neutral 
or only faintly acid aqueous liquid for the acidulous radical of salts. 
In what stage of the process would the following salts be detected ? 
a. Carbonates and Sulphates. 
b. Oxalates. 
c. Tartrates and Nitrates. 
d. Acetates and Sulphites. 
e. Bromides and Cyanides. 
f. Borates. 
g. Iodides and Phosphates. 
h. Chlorates, Oxalates, and Acetates. 
i. Chlorides and Iodides. 
j. Sulphites. 
k. Sulphides, Carbonates, and Nitrates. 
l. Citrates and Sulphates. 
645. Nitrate of silver gives no precipitate in an aqueous solution ; 
vvhat acidulous radicals may be present ? 
646. Chloride of barium gives no precipitate in a neutral solution, 
but nitrate of silver a white ; what acidulous radicals are indicated? 
647. Ferric chloride produces a deep-red color in a solution, chlo- 
ride of calcium yielding no precipitate ; what salts may be present? 
and how may they be distinguished from each other ? 
648. Ferric chloride gives a black precipitate in a solution in which 
sulphuric acid develops no odor ; to what is the effect due ? 
QUESTIONS AND EXERCISES. PRELIMINARY EXAMINATIONS. 
ANALYSIS OF SALTS. 
SINGLE OR MIXED, SOLUBLE OR INSOLUBLE. 
Thus far, all material substances, especially those of pharmaceutical 
interest, have been regarded as being definite compounds, and as 
having certain well-defined parts, termed, for convenience, basylous 
and acidulous respectively ; moreover, attention has been designedly 
restricted to those definite compounds which are soluble in water. 
But there are many substances having no definite or known composi- 
tion ; and of those having definite composition there are many having 
no definite or ascertained parts. Again, of those having definite 
composition, and whose constitution admits of the entertainment of 
theory, there are many insoluble in water. 
Chemical substances of whose composition or constitution little or 
nothing is at present known, are chiefly of animal and vegetable 
origin, and figure in tables of analysis under the convenient collec- 
tive title of “ extractive matterthey are not of immediate import- 
ance, and may he omitted. 
Of substances which are definite in composition, but whose parts 
or radicals, if they have any, are unknown or imperfectly known, 
there are only a few (such as the alkaloids, amylaceous and saccha- 
rine matters, the glucosides, alcoholic bodies, albumenoid, fatty, 
resinoid, and colorific substances) which have any considerable 
amount of medical or pharmaceutical interest; these will be noticed 
subsequently. 
Definite compounds most frequently present themselves; and of 
these by far the larger proportion (namely, the salts soluble in water) 
have already been fully studied. There remain, however, many salts 
which are insoluble in water, but which must be brought into a state 
of solution before they can be effectively examined from any analyt- 
ical, pharmaceutical, or physiological point of view. The next 
subject of laboratory work is, therefore, the analysis of substances 
which may or may not ho soluble in water. This will involve no 
other analytical schemes than those which have been given, wall in 
only one or two cases increase the difficulty of the analysis of the 
precipitate produced by a group-reagent, but will give roundness, 
completeness, and a practical bearing to the reader’s analytical know- 
ledge. Such a procedure will at the same time bring into notice the 
methods by which substances insoluble in water are manipulated for 
pharmaceutical purposes, or made available for use as food by plants, 
or as food and medicine by man and animals generally. 
Preliminary Examination of Solid (chiefly Mineral) Salts. 
Before attempting to dissolve a salt for analysis, its appearance 
and other physical properties should be noted, and the influence of 
heat and strong sulphuric acid be ascertained. If the operator knows 
how to interpret what is thus observed, and to what extent to place 
confidence in the observations, he may more certainly obtain a high 
degree of precision in analysis, and will always gain some valuable GENERAL QUALITATIVE ANALYSIS. 
negative information. But if he has only slight experience of the 
appearance and general properties of bodies, or has the habit of turn- 
ing what should be inferences from tentative processes into foregone 
conclusions, he should omit the preliminary examination altogether, 
or only follow it out under the guidance of a judicious tutor ; for it 
is impracticable here to do more than hint at the results which may 
be obtained by such an examination, or to so adapt description as to 
prevent a student from allowing unnecessary weight to preconceived 
ideas. 
Whatever be the course pursued, short memoranda describing re- 
sults should invariably be entered in the note-book. 
1. Examine the physicial characters of the salt in various 
ways, but never, or only rarely, by the palate, on account of 
the danger to be apprehended. 
If the salt is white, colored substances cannot be present; if 
colored, the tint may indicate the nature of the substance or of one 
of its constituents, supposing that the learner is already acquainted 
with the colors of salts. Closer observation, aided perhaps by a 
lens, may reveal the occurrence, in a pulverulent mixture, of small 
crystals or pieces of a single substance ; these should be picked out 
by a needle and examined separately. In a powder or roughly di- 
vided mixture of substances, the process of sifting (through such 
sieves as muslin of different degrees of fineness) often mechanically 
separates substances, and thus greatly facilitates analysis. The 
body may present an undoubted metallic appearance, in which case 
only the metals existing under ordinary atmospheric conditions need 
be sought. Peculiarity in smell reveals the presence of ammonia, 
hydrocyanic acid, hydrosulphuric acid, etc. Between the fingers a 
substance is, perhaps, hard, soft, or gritty; consequent inferences 
follow. Or the matter may be heavy, like the salts of barium or 
lead; or light, like the carbonates and hydrates of magnesium; or 
may be one of the pharmaceutically well-known class of “scale” 
preparations. 
2. Place a grain or two of the salt in a small dry test-tube 
or in a piece of ordinary tubing, closed at one end, and heat it, 
at first gently, then more strongly, and finally, if necessary, by 
the blowpipe. 
Gases or vapors of characteristic appearance or odor may be 
evolved; such as iodine, nitrous fumes, sulphurous, hydrocyanic, or 
ammoniacal gases. Much steam given by a dry substance indicates 
either hydrates or salts containing water of crystallization. (A 
small quantity of interstitial moisture often causes heated crystalline 
substances to decrepitate—from decrepo, I crackle—that is, break 
up with slight explosive violence, owing to the expansive force of 
the steam suddenly generated). A sublimate may be obtained, due 
to salts of mercury or arsenicum, to oxalic or benzoic acid, or to sul- 
phur free or as a sulphide—a salt wholly volatile containing such PRELIMINARY EXAMIXATTOXS. 
substances only. The compound may blacken, pointing to the pre- 
sence of organic matter—which, in common definite salts, will prob- 
ably be in the form of acetates, tartrates, and citrates, or as common 
salts of the alkaloids morphine, quinine, strychnine, or as starch, sugar, 
salicin, or in other definite or indefinite forms common in pharmacy 
and for which tests will be given in subsequent pages. If no char- 
ring occurs, the important fact that no organic matter is present is 
established. The residue may change color from presence or develop- 
ment of oxide of zinc, oxide of iron, etc., or melt from the presence 
of a fusible salt and absence of any large proportion of infusible 
salts, or, lieing unaltered, showing the absence of any large amount 
of such substances. 
3. Place a grain or two of the salt in a test-tube, add a drop 
or two of strong sulphuric acid, cautiously smelling any gas 
that may be evolved; afterward slowly heat the mixture, 
noticing the effect, and stopping the experiment w hen any sul- 
phuric fumes begin to escape. 
Iodine, bromine, and nitrous or chlorinoid fumes will reveal them- 
selves by their color, indicating the presence of iodides, bromides, 
iodates, bromates, nitrates, and chlorates. The evolution of a color- 
less gas fuming on coming into contact with air, and having an irri- 
tating odor, points to chlorides, fluorides, or nitrates. Gaseous prod- 
ucts having a greenish color and odor of chlorine indicate chlorates, 
hypochlorites, or chlorides mixed with other substances. Slight 
sharp explosions betoken chlorates. Evolution of colorless gas may 
proceed from cyanides, acetates, sulphides, sulphites, carbonates, or 
oxalates. Charring will be due to citrates, tartrates, or other organic 
matter. If none of these effects are produced, most of the bodies 
are absent or only present in minute quantity. The substances 
apparently unaffected by the treatment are metallic oxides, borates, 
sulphates, and phosphates. 
4. Exposure of the substances to the blowpipe-flame, on plat- 
inum wTire w ith or without a bead of borax or microcosmic salt 
(phosphate of sodium, ammonium, and hydrogen, NaAmHPO*) 
—on platinum foil, in a porcelain crucible, or on a crucible-lid 
with or without carbonate of sodium—on charcoal, alone or in 
conjunction with carbonate of sodium, cyanide of potassium, 
or nitrate of cobalt, will sometimes yield important informa- 
tion, especially to one who has devoted much attention to re- 
actions produceable by the blowpipe-flame. The medical or 
pharmaceutical student, however, will seldom have time to work 
out this subject to an extent sufficient to make it a trustworthy 
guide in analysis. (See Plattner and Muspratt On the Use 
of the Blowpipe, and a chapter in Galloway’s Manual of 
Quantitative Analysis. 370 
GENERAL QUALITATIVE ANALYSIS. 
Methods of Dissolving and Analyzing Single or Mixed Solid Sub- 
stances. 
Having submitted the substance to preliminary examination, pro- 
ceed to dissolve and analyze by the following methods. These ope- 
rations consist in treating a well-powdered substance consecutively 
with cold or hot water, hydrochloric acid, nitric acid, nitro-hydro- 
chloric acid, or fusion with alkaline carbonates and solution of the 
product in water and acid. Resulting liquids are analyzed in the 
manner already described, or by slightly modified processes as de- 
tailed in the folioicing paragraphs. 
Solution in Water.—Boil about a grain of the salt presented 
for analysis in about a third of a test-tubeful of water. If it 
dissolves, prepare a solution of about 20 or 30 grains in half an 
ounce or more of water, and proceed with the analysis in the 
usual way, testing first for the basylous radical or radicals by 
the proper group reagents (HC1, 1I2S, AmHS, Am2C03, 
Am2IIP04), p. 220 or 255, and then for the acidulous radical 
or radicals, directly or by aid of the prescribed reagents 
(H2S04, BaCl„ CaCl2, AgNO„ FeaCl,), p. 304. 
If the salt is not wholly dissolved by the water, ascertain 
whether or not any has entered into solution, by filtering, if 
necessary, and evaporating a drop or two of the clear liquid to 
dryness on platinum foil; the presence or absence of a residue 
gives the information sought. If anything is dissolved, pre- 
pare a sufficient quantity of solution for analysis and proceed 
as usual, reserving the insoluble portion of the mixture, after 
thoroughly exhausting with water, for subsequent treatment 
by acids. 
Solution in Hydrochloric Acid.—If the salt is insoluble in 
water, digest about a grain of it (or of the insoluble portion 
of a mixed salt) in a few drops of hydrochloric acid, adding 
water, and boiling if necessary. If the salt wholly dissolves, 
prepare a sufficient quantity of the liquid, noticing whether or 
not any effervescence (due to the presence of sulphides, sul- 
phites, carbonates, or cyanides) occurs, and proceed with the 
analysis as before, except that the first step, the addition of 
hydrochloric acid, may be omitted. 
The analysis of .this solution will in most respects be simpler than 
that of an aqueous solution, inasmuch as the majority of salts (all 
those soluble in water) will be absent. This acid solution will, in 
short, only contain : chlorides produced by the action of the hydro- 
chloric acid on sulphides, sulphites, carbonates, cyanides, oxides, 
and hydrates; and certain borates, oxalates, phosphates, tartrates, 
and citrates (possibly silicates and fluorides) which are insoluble in 
water, but soluble in acids without apparent decomposition. The first METHODS OF EFFECTING SOLUTION. 
four—sulphides, sulphites, carbonates, and cyanides—will have re- 
vealed themselves by the occurrence of effervescence during solution ; 
and the presence of oxides and hydrates may often be inferred by 
the absence of compatible acidulous radicals. The borates, oxalates, 
phosphates, tartrates, and citrates alluded to will be reprecipitated 
in the general analysis as soon as the acid of the solution is neutral- 
ized ; that is, will come down in their original state when ammonia 
and sulphydrate of ammonium are added to the usual course. Of 
these precipitates, only the oxalate of calcium and the phosphates 
of calcium and magnesium need occupy attention now; for oxalate 
and phosphate of barium seldom or never occur, and the borates, 
tartrates, and citrates met with in medicine or in general analysis 
are all soluble in water. These phosphates and oxalates, then, will 
be precipitated in the course of analysis along with iron, their pres- 
ence not interfering with the detection of any other metal. If. from 
the unusual light color of the ferric precipitate, phosphates and 
oxalates are suspected, it is treated according to the following 
Table (reference to which should be inserted in the Table for metals, 
under Fe, pp. 220 and 255). 
PRECIPITATE OF PHOSPHATES, OXALATES, AND FERRIC HYDRATE. 
Dissolve in HC1, add citric acid, then NIIJIO, and filter. 
Filtrate 
Fe. 
Add HC1 and 
K4Fcy. 
Blue ppt. 
Precipitate 
Ca32P04, CaC,04, Mg32P04. 
Boil in acetic acid and filter. 
Insoluble 
CaC204.* 
White. 
(CaF2 may 
occur here.) 
Filtrate 
Ca32P04, Mg32P04. 
Add Am2C204, stir, filter. 
Precipitate 
white, including 
C’a22P03. 
Filtrate. 
Add Am HO. 
White ppt. 
MgNH4P04. 
In analyzing phosphates and oxalates advantage is also frequently 
taken of the facts that the phosphoric radical is wholly removed 
from solution of phosphates in acid by the addition of an alkaline 
acetate, ferric chloride, and subsequent ebullition, as described un- 
der “Phosphoric Acid” (p. 328), and that dry oxalates are converted 
into carbonates by heat, as mentioned under “Oxalic Acid” (p. 314). 
See also p. 328, 4th Analytical Reaction. 
* Oxalates after being heated effervesce on the addition of acid; fluo- 
rides may he detected by the “ etching test.” 372 
GENERAL QUALITATIVE ANALYSIS. 
Certain arseniates and arsenites, insoluble in water but soluble in 
hydrochloric acid, may accompany the above phosphates and oxa- 
lates if from any cause hydrosulphuric acid gas has not been pre- 
viously passed through the solution, or passed for an insufficient 
length of time. 
If the substance insoluble in water does not wholly dissolve 
in hydrochloric acid, ascertain if any has entered into solution, 
by filtering, if necessary, and evaporating a drop of the clear 
liquid to dryness on platinum foil; the presence or absence of a 
residue gives the information sought. If anything is dissolved, 
prepare a sufficient quantity of solution for analysis, and proceed 
as usual, reserving the insoluble portion of the mixture, after 
thoroughly exhausting with hydrochloric acid and well washing 
with water, for the following treatment by nitric acid. 
Solution in Nitric Acid.—If the salt is insoluble in water 
and hydrochloric acid, boil it (or that part of it which is in- 
soluble in those menstrua) in a few drops of nitric acid. If it 
wholly dissolves, remove excess of acid by evaporation, dilute 
with water, and proceed with the analysis. 
This nitric solution can contain only very few substances; for 
nearly all salts soluble in nitric acid are also soluble in hydrochloric 
acid, and therefore will have been removed previously. Some of the 
metals, however (Ag, Cu, Hg, Pb, Bi), as well as amalgams and 
alloys, unaffected or scarcely affected by hydrochloric acid, are read- 
ily attacked and dissolved by nitric acid. Many of the sulphides, 
also insoluble in hydrochloric acid, are dissolved by nitric acid, 
usually with separation of sulphur. Calomel is converted, by long 
boiling with nitric acid, into mercuric chloride and nitrate. The 
nitrates here produced are soluble in water. 
This nitric solution, as well as the hydrochloric and aqueous solu- 
tions, should be examined separately. Apparently time would be 
saved by mixing the three solutions together and making one analy- 
sis. But the object of the analyst is to separate every radical from 
every other; and when this has been partially accomplished by sol- 
vents, it would be unwise to again mix and separate a second time. 
Moreover, solvents often do what the chemical reagents cannot— 
namely, separate salts from each other. This is important, inas- 
much as the end to be obtained in an analysis is not only an enu- 
meration of the radicals present, but a statement of the actual con- 
dition in which they are present; the analyst must, if possible, state 
of what salts a given mixture was originally formed—how the basy- 
lous and acidulous radicals were originally distributed. In attempt- 
ing this, much must be left to theoretical considerations; but a pro- 
cess by which the salts themselves are separated is of trustworthy 
practical assistance; hence the chief advantage of analyzing sepa- 
rately the solutions resulting from the action of water and acids on 
a solid substance. 
Solution in Nitro-Hydrochloric Acul.—If the salt or any ANALYSIS OF INSOLUBLE SUBSTANCES. 
373 
part of a mixture of salts is insoluble in water, hydrochloric 
acid, and nitric acid, digest it in nitro-hydrochloric acid, warm- 
ing or even boiling gently if necessary; evaporate to remove 
excess of acid, dilute, and proceed as before. 
Sulphide of mercury and substances only slowly attacked by hy- 
drochloric or nitric acid, as, for example, calomel and ignited ferric 
oxide, are sufficiently altered by the free chlorine of aqua regia to 
become soluble. 
Analysis of Insoluble Substances. 
If the substance is insoluble in water and acids, it is one or 
more of the following substances : Sand and certain silicates, 
such as pipeclay and other clays; fluor spar; cryolite (3NaF,- 
A1F3) ; sulphates of barium, strontium, and possibly calcium ; 
tinstone; antimonic oxide; glass; felspar (double silicate of 
aluminium and other metals) ; chloride of silver ; sulphate of 
lead. It may also be or contain carbon or carbonaceous mat- 
ter, in which case it is black and combustible, burning entirely 
or partially away when heated in the air; or be or contain sul- 
phur, in which case sulphurous gas is evolved, detected by its 
odor, when the substance is heated in the air. A drop of so- 
lution of sulphydrate of ammonium added to a little of the 
powder, will at once indicate the presence or absence of salts 
of such metals as lead and silver. For the other substances 
proceed according to the following (Bloxam’s) method :— 
Four or five grains of the dry substance are intimately mixed 
with twice the quantity of dry carbonate of sodium, and this 
mixture well rubbed in a mortar with five times its weight of 
deflagrating flux (1 of finely-powdered charcoal to 6 of nitre). 
The resulting powder is placed in a thin porcelain dish, or 
crucible, or clean iron tray, and a lighted match applied to the 
centre of the heap. Deflagration ensues, and decomposition of 
the various substances occurs, the acidulous radicals going to 
the alkali-metals to form salts soluble in water,.the basylous 
radicals being simultaneously converted into carbonates or 
oxides. The mass is boiled in water for a few minutes, the 
mixture filtered, and the residue well washed. The filtrate 
may then be examined for acidulous radicals and aluminium, 
and the residue dissolved in dilute hydrochloric acid and ana- 
lyzed by the ordinary method. 
The only substance which resists this treatment is chrome-iron 
ore. 
To detect alkali in felspar, glass, or cryolite, Bloxam recommends 
deflagration of the powdered mineral with one part of sulphur and 
six of nitrate of barium. The mass is boiled in water, the mixture 374 
GENERAL QUALITATIVE ANALYSIS. 
filtered, hydrate and carbonate of ammonium added to remove ba- 
rium, the mixture again filtered, and the filtrate evaporated and ex- 
amined for alkalies by the usual process. 
Hydrates and Oxides. 
If no acidulous radical can be detected in a substance under 
analytical examination, or if the amount found is obviously in- 
sufficient to saturate the quantity of basylous radical present, 
the occurrence of oxides or hydrates, or both, may be suspected. 
Confirmation of their presence will be found in the general 
rather than in any special behavior of the substances. Some 
hydrates yield water when heated—in a dry test-tube held 
nearly horizontally in a flame, so that moisture may condense 
on the cool part of the tube. Some oxides yield oxygen—de- 
tected by heating in a test-tube, and inserting the incandescent 
end of a strip of wood. Soluble hydrates cause abundant evo- 
lution of ammonia gas when heated with solution of chloride 
of ammonium. Soluble hydrates also give characteristic pre- 
cipitates with the various metallic solutions. Hydrates and 
oxides insoluble in water not only neutralize much nitric acid 
or acetic acid, but are thereby converted into salts soluble in 
water. Most oxides and hydrates have a characteristic appear- 
ance. In short, some one or more properties of an oxide or a 
hydrate will generally betray its presence to the student who 
not only has knowledge respecting chemical substances, but 
has cultivated the faculties of observation and perception. 
649. Describe the preliminary treatment to which a salt may be 
subjected prior to systematic analysis. 
650. Mention substances which might be recognized by smell. 
651. Which classes of salts are heavy, and which light? 
652. Name some bodies detectable by their color. 
653. What inference may be drawn from the appearance of steam 
when dry substances are heated ? 
654. Why do certain crystals decrepitate ? 
655. If a powder sublimes on being heated, to what classes of 
compounds may it belong? 
656. When heat causes charring, what conclusion is drawn? 
657. No change occurring by heat, which substances cannot be 
present ? 
658. Give example of salts which are identified by their reaction 
with strong sulphuric acid ; and by their comportment in the blow- 
pipe-flame, with or without borax or microcosmic salt. 
659. What are the solvents usually employed in endeavoring to 
QUESTIONS AND EXERCISES. RECAPITULATORY AND OTHER NOTES. 
obtain a substance in a state of solution, and what is the order of 
their application? 
660. Name a few salts which may be present in an aqueous solu- 
tion. 
661. Mention some common compounds insoluble in water, but 
soluble in hydrochloric acid. 
662. What substances are attacked only by nitric acid or nitro- 
hydrochloric acid ? 
663. At what stage of analysis do arsenites and arseniates show 
themselves ? 
664. Sketch out a method for the complete analysis of a liquid 
suspected to be an aqueous solution of neutral salts. 
665. IIow can earthy phosphates and oxalates with ferric oxide 
be separated from each other? 
666. IIow would you proceed to analyze an alloy? 
667. By what process may substances insoluble in water or acids 
be analyzed ? 
668. IIow would you qualitatively analyze glass? 
Recapitulatory and other Notes on the Constitution of the 
Definite Chemical Compounds commonly termed Salts. 
The molecules of a salt contain radicals—which may be either 
elementary or compound: pp. 37 and 66. 
Each radical has a definite exchangeable value: p. 120. 
The definite exchangeable values of radicals differ in different 
series of radicals: p. 121. 
In one and the same molecule of a salt, two or more different 
atoms of the same element may possess the two distinct functions 
of being (a) a single definite distinct radical and (It) one member of 
a group of atoms which together form a single definite distinct rad- 
ical : p. 260. 
The relation to each other, either of the elementary or the com- 
pound radicals in organic substances or salts, is apparently far more 
complex than the relation to each other of the elementary and com- 
pound radicals in inorganic or mineral salts: pp. 377 ana 378. 
The properties of salts are regarded as depending on («) the 
nature, (/>) the number, and (e) the position in relation to each 
other of the elementary and compound radicals in a molecule. 
Dumas, afterwards Laurent, and then Gerhard, attempted the 
classification of salts under such types as the following:— 
II I 
Hi 
The hydrogen type. 
11) 
II N 
Hj 
The ammonia type. 
11 to 
The water type. 
Other chemists have extended the number of such types of salts. 
Further, by writing the typical formulae in the above and other man- 
ners a mode of indicating the facts assumed to be dependent on the 
position of the atoms in a molecule has been sought to be obtained. 376 
CHEMISTRY OF ORGANIC SUBSTANCES. 
Finally, the natural development of this train of thought and of 
practice has produced the graphic formula; of Kekule, Frankland, 
and others. 
Caution.—The conjectural or theoretic character of our ideas re- 
specting masses of matter being formed of molecules, and molecules 
of atoms, and that molecules contain radicals consisting of one or 
more atoms, must never be lost sight of—highly valuable and prac- 
tically useful though the hypotheses be: pp. 38, 50, 260, 261, 283, 
299. 
Berthollef s Laws.—“ When we cause two salts to react by means 
of a solvent, if, in the course of double decomposition, a new salt 
can be produced less soluble than those which we have mixed, this 
salt will be produced. When we apply dry heat to two salts, if, by 
double decomposition, a new salt can be produced more volatile than 
the salts previously mixed, this salt will be produced.” 
Malaguti's Law.—When solutions of two different salts are mixed, 
and metathesis occurs and four salts result, the proportions of the 
salts to each other are dependent on the strength or intensity of 
force with which the respective basylous and acidulous radicals are 
united. 
The state of equilibrium just mentioned may be permanent or 
temporary. The latter condition obtains when one of the salts 
which may possibly be produced is insoluble, for as soon as pre- 
cipitation occurs the equilibrium is upset, and is re-established 
only to be upset again, and so on until from the four salts there 
result one in solution and one out of solution. This would seem to 
be the way in which the laws termed Berthollet’s work. 
CHEMISTRY OF CERTAIN SUBSTANCES OF 
VEGETABLE AND ANIMAL ORIGIN. 
Except alcohol and a few acids, the compounds which have hith- 
erto engaged notice have been of mineral origin. But the two 
other kingdoms of nature, the animal and vegetable, furnish a 
large number of definite substances. These, indeed, when discov- 
ered, were producible only by organized living structures, and were 
hence termed organic compounds.* 
A few of these compounds of common occurrence in pharmacy, 
and possessing prominent characteristics, may now occupy atten- 
tion ; reactions of the alkaloids and some other principles may be 
performed, and the methods of examining morbid urine be exper- 
imentally studied. There will then remain to be studied certain 
galenical, as distinguished from chemical, substances, solid and 
* Organic, from ogyavov, organon, an organ. A large number of organic 
compounds can now be obtained artificially—without the aid of a living 
organism; hence the distinction formerly drawn between organic and 
inorganic compounds, organic and inorganic chemistry, is fast breaking 
down. THE ALKALOIDS. 
377 
liquid, which can only be fairly regarded from a pharmacist’s 
rather than a chemist’s point of view, and a still larger number, 
doubtless, not yet brought within the grasp of chemist or pharma- 
cist, and of which, therefore, we must at present be content to 
remain in ignorance. An opportunity, however, will be afforded 
of noticing the effect of such organic matter as a vomit or the con- 
tents of a stomach in masking or preventing the reactions by which 
mineral and vegetable poisons are detected. 
Constitution of Alkaloids or Organic Bases. 
ALKALOIDS. 
Natural Alkaloids.—The alkaloids, or alkali-like bodies (elSoc, 
eidos, likeness), have many analogies with ammonia. Their consti- 
tution is not yet known ; but they are probably derivatives of a 
single molecule of ammonia (NH3), or of double, triple, or quad- 
ruple molecules (N2II6, N3H9, N4II12). 
Artificial Alkaloids.—Numerous artificial alkaloids or organic 
bases, unquestionably having the constitution just mentioned, have 
already been formed. These are sometimes termed amines, and are 
primary, secondary, and tertiary, according as one, two, or three 
atoms of hydrogen in ammonia have been displaced by radicals, as 
seen in the following general formulae (R = any univalent radical. 
Vide Index, “ Alcohol Radicals”):— 
R) 
II > N 
H) 
R) 
R ' N 
II] 
R) 
R l N 
Rj 
or the following examples :— 
c2h5) 
II N 
H) 
Ethylamine or 
ethylia (C2H7N). 
C2II5) 
c2h5 n 
ii) 
Diethylamine or 
diethylia (C4HnN). 
C2H5 
CA N 
c2h5J 
Triethvlamine or 
triethylia (C6II15N). 
The three classes have also been termed amidogen-, imidogen-, and 
nitrile-bases. 
Mode of Formation of Artificial Alkaloids.—A few illustrations 
will suffice. Just as the addition of iodide of hydrogen (III) to 
ammonia (that is, the common tri-hydrogen ammonia, NII3) gives 
iodide of common ammonium (NHHIIHI or NII4I), so the addition 
of iodide of ethyl (C2II5I or EtI) (see Index) to ammonia (NH3) 
gives the iodide of ethyl-ammonium (NHHIIEtl, or NII3EtI, or 
NII3C2II5I). A fixed alkali turns out common ammonia (NHHH) 
from the iodide (or any other salt) of common ammonium; it turns 
out ethyl-ammonia (NHHEt) from the iodide (or any other salt) 
of ethyl-ammonium. Ethyl-ammonia (or ethglia, or ethylamine), 
NIIHEt, with iodide of ethyl, EtI, gives iodide of diethyl-ammonium 
(NHHEtEtl, or NH2Et2I, or NH2[C2H5]2I). From the latter, pot- 
ash turns out diethyl-ammonia (NHEt2) ; diethyl-ammonia (diethylia 378 
THE ALKALOIDS. 
or diethylamine) with iodide of ethyl gives iodide of triethyl-am- 
monium (NIIEt3l). The latter with alkali gives triethyl-ammonia 
or triethylia or triethylamine (NEts), and this with iodide of ethyl 
gives iodide of tetrethy 1-ammonium, NEt4I. 
What has just been stated respecting iodide of ethyl is true of 
other salts of ethyl; and what is true of salts of ethyl is true of salts 
of an immense number of other radicals—univalent, bivalent, etc.— 
so that a vast number of artificial alkaloids and their salts can be 
produced. The reactions are not always so sharp as those just given. 
Mixtures of primary, secondary, and tertiary compounds rather than 
either alone often result in an experiment; but the reactions are 
typically true. 
Some of these artificial alkaloids not only resemble natural alka- 
loids, but are strong caustic liquids, like solution of ammonia. 
Then, the displacing radical in an artificial alkaloid or its salt may 
not only be of one kind, as indicated in the preceding paragraphs, 
but of different kinds; and while the radical displacing one atom of 
hydrogen is keeping its place, any of the many known radicals may 
occupy the position of one or all of the other atoms of hydrogen. 
Thus, for example, we have methyl-ethyl-amyl-amine (C8II19N, or 
CH3C2II5C5IIuN, or MeEtAyN), a colorless oily body, of agreeable 
aromatic odor. The empirical formulae of morphine, quinine, etc. may 
some day be similarly resolvable into rational formulae. Their arti- 
ficial production will then quickly follow. 
Methylamine (CH3HHN), and trimethylamine (CH3)3N, are artificial 
alkaloids which have been found by Schmidt in Mercurialis annua 
and M. perennis, and previously by Reichardt, who termed them rner- 
curialine. Trimethylamine is also produced in large quantities in 
the dry distillation of the evaporated residue of the spent wash pro- 
duced in beet-root spirit distilleries. 
Propylamine or tritylia (C3HTHHN) is a volatile oil, one product 
of the destructive distillation of bones and other animal matters. 
The organic bases derived from one molecule of ammonia are 
termed monamines ; from two molecules, diamines ; from three, tria- 
mines ; and from four, tetramines :— 
R1 
R l N 
RJ 
R.) 
H, V N2 
rJ 
Ra 
«a Ns 
Rai 
R* 
R* \ n4 
rJ 
In these amines any bivalent, trivalent, or quadrivalent radical may 
occupy the place of two, three, or four univalent radicals. 
Evidence of Constitution of the Natural Alkaloids.—Attempts to 
form artificially the important natural organic bases have hitherto 
failed ; but the primary, secondary, or tertiary character of some of 
them has been indicated by the introduction or elimination of methyl, 
ethyl, and other radicals for hydrogen. 
Note on Nomenclature of Natural Alkaloids.—The first syllables 
of the names of the natural alkaloids recall the name of the plant 
whence they were obtained or some characteristic property. It is to 
be regretted that the last syllable is not either ine or ia, instead of 
sometimes one and sometimes the other. In the United States the MORPHINE. 
379 
termination ine is officially adopted, although the termination ia is 
still frequently employed. The names of the salts of the alkaloids 
are given on the assumption that the acid unites with the alkaloid 
without decomposition. Thus hydrochlorate of morphine is regarded 
as morphine with hydrochloric acid, just as we might assume sal- 
ammoniac to be ammonia (NII3) with hydrochloric acid (IIC1), and 
name it hydrochlorate of ammonia (NII3IIC1) instead of chloride of 
ammonium (NII4C1). All acids, even sulphydric, unite with alka- 
loids and form salts having similar names. 
Antidotes.—In cases of poisoning by alkaloids, emetics and the 
stomach-pump must be relied on rather than chemical agents. But 
astringent liquids may be administered, for tannic acid precipitates 
many of the alkaloids from their aqueous solution, absorption of the 
poison being thus possibly retarded. 
MORPHINE, OR MORPHIA. 
Formula C17H19N03,H20. Molecular weight 303. 
Occurrence.—Morphine occurs in opium (the inspissated juice of 
the fruit, Papaveris capsulce, of the White Poppy, Papaver somnif- 
erum) as meconate of morphine [(Ci7H19N03)2, C71I407, 51I20 ; I)ott.]. 
The dried poppy-capsule of pharmacy contains opium principles, 
but varying much in nature and proportion. The presence in the 
capsule of morphine, narcotine, and meconic acid have been demon- 
strated, and, by Groves, of narceine and codeine. Ordinary Asia 
Minor opium {Opium, U. S. P.) (Turkey, Smyrna, or Constantinople 
opium) should contain “ not less than 9 per cent, of morphine,” and 
when dried at 85° C. and powdered {Opii Pulvis, U. S. P.), from 12 
to 16 per cent, of morphine. 
Denarcotized Opium {Opium Denarcotisatum, U. S. P.) is dried 
and powdered opium from which narcotine has been washed out by 
ten times its weight of stronger ether, the product being re-dried at 
85° C., and made up to its original weight with powdered sugar of 
milk. 
Morphina, U. S. P., may be made by adding to infusion of opium 
an equal bulk of alcohol, then slight excess of ammonia, and setting 
aside for crystalline morphine to separate. It is purified by recrys- 
tallization. 
Process for Ihjdrochlorate.—The hydrochlorate, C17H19N03,HC1,- 
3II20 {Morphines Htjdrochloras, U. S. P.), occurs in slender white 
acicular crystals. It is prepared by simply decomposing an aqueous 
infusion of opium with chloride of calcium, meconate of calcium and 
hydrochlorate of morphine being produced. (If the infusion, which 
is always acid, be first nearly neutralized by the cautious addition of 
small quantities of very dilute solution of ammonia, the chloride 
of calcium then at once causes a precipitate of meconate of calcium, 
which can be filtered off, leaving a colored solution of hydrochlorate 
of moi'phine. On the large scale {vide B. P.) the details are some- 
what different.) The salt is partially purified by crystallization 380 
THE ALKALOIDS. 
from the evaporated liquid, then by treatment of the solution of 
the impure hydrochlorate by animal charcoal, and lastly, by pre- 
cipitation of the morphine from the still colored liquid by ammonia 
and re-solution of the morphine in hot dilute hydrochloric acid ; 
hydrochlorate of morphine separates out on cooling. 
Hydrochlorate of morphine deposited from a hot solution in about 
twenty times its weight of alcohol is anhydrous. 
Morphine may also, of course, be prepared by the methods given 
for its quantitative separation from opium (see Index). 
Morphince Sulphas, U. S. P. (2CnlI19N03,II2S04,5II20) may be 
made by neutralizing morphine with sulphuric acid. It is a con- 
stituent of Pulvis Morphince Compositus. 
Process for Acetate.—Acetate of morphine (CnII19N03,C2II402) 
(Morphince Acetas, U. S. P.) is a white pulverulent salt prepared 
by dissolving pure morphine in acetic acid. One grain of acetate, so 
made, in twelve minims of water, forms the Injectio Morphias Hypo- 
dermica, B. P. 
Both the hydrochlorate and acetate of morphine are soluble in water, 
but the solution is not stable unless acidulated and containing alco- 
hol ; hence the official solutions, 4 grains in one ounce, 1 in 110 
{Liquor Morphias Hydrochloratis, B. P., and Liquor Morphias Acetatis, 
B. P.), consist of three parts water and one part rectified spirit, a 
few minims per ounce of hydrochloric or acetic acid being added. 
Even solid acetate of morphine is unstable, slowly dissociating into 
acetic acid and morphine ; hence the acid odor of acetate of morphine. 
Solubility of morphine salts in water at 60° F. According to Dott, 
1 part of the respective salts is soluble in the annexed number of 
parts of water: Acetate, 2h; Tartrate, 9f; Sulphate, 23; Hydro- 
chlorate, 24; Meconate, 34. 
Other alkaloids exist in opium. In the above process a consider- 
able quantity of an alkaloid of very weak basic properties, narcotine 
(C22II23N07) (Narcotina, P. I.) remains in the exhausted opium, and 
may be extracted by digesting in acetic acid, filtering, precipitating 
by ammonia. It crystallizes in brilliant needles from alcohol or 
ether. By oxidation it yields cotarnine and an acid termed opianic. 
Codeine (C18H2lN03,H20) (Codeina, U. S. P.) is soluble in the slight 
excess of ammonia employed in precipitating the morphine. u Codeine 
is dissolved by sulphuric acid containing 1 per cent, of molybdate 
of sodium to a liquid having, at first, a dirty-green color, which, after 
a while, becomes pure blue, and gradually fades, within a few hours, 
to pale yellow. On dissolving codeine in sulphuric acid a colorless 
liquid results, which, on the addition of a trace of ferric chloride 
and gentle warming, becomes deep blue. An aqueous solution of 
codeine, added to test-solution of mercuric chloride, should produce 
no precipitate ; and if codeine be added to nitric acid of sp. gr. 1.200, 
it will dissolve to a yellow liquid which should not become red (differ- 
ence from and abs. of morphine).”—U. S. P. From the mother- 
liquors there have also been obtained thehaine (C]91I2IN03), papa- 
verine (C211I21N04), opianine (C21II21NO. ?), narceine (C231I29N09), 
cryptopine (P21II23N05), meconine (C10Il10O), meconoisine (C8ll10O2), 
laudanine (C20H23NO4), codamine (C20H25NO4), gnoscopine (C34Il3(i- MORPHINE. 
381 
N2On), pseudomorphine (C17H19N04), protopine (C20II19NO5), lauda- 
nosine (C21H2.N 04), hydrocotarnine (C12H15N 0:j), rhceadine (C20 H21N 06), 
meconidine (0211123 N04), lanthopine (C23H25N04). A little acetic acid 
also exists in all opium (D. Brown). 
Analytical Reactions. 
First Analytical Reaction.—To a minute fragment of a salt 
of morphine add one drop of water, and warm the mixture until 
the salt dissolves, then stir the liquid with a glass rod moist- 
ened by a strong neutral solution of perchloride of iron; a 
dirty-blue color is produced. This effect is not observed in 
dilute solutions. 
Second Analytical Reaction.—To a drop or two of a strong 
solution of a morphine salt in a test-tube add a minute fragment 
of iodic acid (III03; page 293) ; iodide is set free. Into the 
upper part of the tube insert a glass rod covered with mucilage 
of .starch, and warm the solution; dark-blue starch iodide is 
produced. If the mixture of morphine and iodic acid be shaken 
up with chloroform or bisulphide of carbon, a violet solution is 
obtained. 
This reaction is only confirmatory of others, as albumenous matters 
also reduce iodic acid. 
Third, Analytical Reaction.—To a few drops of an aqueous 
infusion of opium add a drop of neutral solution of perchloride 
of iron ; a red solution of meconate of iron is produced. Add 
solution of corrosive sublimate; the color is not destroyed 
(as it is in the ease of sulphocyanate of iron, a salt of similar 
tint). 
In cases of poisoning by a preparation of opium this test is almost 
as conclusive as a direct reaction of morphine (the poison itself), 
meconic acid being obtainable from opium only. 
Other Reactions—Add carbonate of sodium to a solution of 
a salt of morphine ; a white precipitate of morphine falls, slowly 
and of a crystalline character if the solution is dilute. Collect 
this precipitate, and moisten it with neutral solution of perchlo- 
ride of iron ; the bluish tint above referred to is produced. 
Add an alkali to a solution of hydrochlorate or acetate 
of the alkaloid; morphine is precipitated, soluble in excess of 
the fixed alkali; far less readily so in ammonia. Moisten a 
particle of a morphine salt with nitric acid; an orange-red col- 
oration is produced. To morphine add strong sulphuric acid, 
mix, and strew nitrate of bismuth on the fluid; the mixture 
turns dark brown or black. Heat morphine on platinum foil; 
it burns entirely away. 382 
THE ALKALOIDS. 
Apomorphine (C17II17N02). 
Apomorphine (a7ro, apo, from, and morphine) is an alkaloid obtained 
from morphine by Matthiesson and Wright. It possesses remarkable 
physiological effects: one-tenth of a grain (in aqueous solution) in- 
jected under the skin, or one quarter of a grain taken into the 
stomach, is said to produce vomiting in from four to ten minutes. 
Process.—Hydrochlorate of morphine is hermetically sealed in a 
thick tube with considerable excess of hydrochloric acid, and heated 
to nearly 300° F. for two or three hours. The product is purified 
by diluting the contents of the tube with water, precipitating with 
bicarbonate of sodium, and treating the precipitate with ether or 
chloroform. On shaking up the ethereal or chloroform solution 
with a very small quantity of strong hydrochloric acid, the sides of 
the vessel become covered with crystals of the hydrochlorate of the 
new base. These may be drained from the mother-liquor, washed 
with a little cold water, in which the salt is sparingly soluble, recrys- 
tallized from hot water, and dried on bibulous paper or over sulphuric 
acid. The formula (C17H17N02,HC1) indicates that the new alkaloid 
is derived from morphine by abstraction of the elements of water. 
Hydrochlorate of apomorphine (Apomorphince HydrochlorasfJ. S. P.) 
occurs in “colorless or grayish-white, shining crystals, turning green- 
ish on exposure to light and air, odorless, having a bitter taste and 
a neutral or faintly acid reaction. Soluble in 6.8 parts of water and 
in 50 parts of alcohol at 15° C. (59° F.); slowly decomposed by boil- 
ing water or boiling alcohol; almost insoluble in ether or chloro- 
form ; should it impart color to either of these liquids it should be 
rejected, or it may be purified by thoroughly agitating it with either 
liquid, filtering, and then rapidly drying the salt on bibulous paper 
in a dark place. The aqueous solution, on gentle warming, rapidly 
turns green, but retains a neutral reaction. Solution of bicarbonate 
of sodium, added to an aqueous solution of the salt, throws down 
the white, amorphous alkaloid, which soon turns green on exposure 
to air, and forms a bluish-green solution with alcohol, a purple one 
with ether or pure benzol, and a violet or blue one with chloroform.” 
Codeine also, according to the same chemists, yields apomorphine 
by similar treatment, a reaction that would seem to indicate that 
codeine is methyl-morphine ; indeed, Grimaux (Hesse also) has since 
obtained codeine—or, possibly, an isomer of codeine, methyl-mor- 
phine—from morphine. 
with a vi 
the vesse 
new base. 
C17HnCH3IIN03 + HC1 = CII3CI + H20 + CnHI7N02 
Codeine. 
Chi. of methyl. 
ApomorpUiue. 
Dr. C. R A. Wright lias recently obtained several new derivatives 
of codeine. 
Codeine neither gives a blue color with ferric chloride nor a red 
with nitric acid. Both codeine and morphine, when heated with a 
mixture of strong sulphuric acid and arseniate of sodium, give a 
blue color, the morphine yielding a greenish-blue and the codeine a 
violet-blue. QUININE. 
QUESTIONS AND EXERCISES. 
669. Write some general formulae of artificial alkaloids. 
670. Name the substances represented by the following formulae:— 
C3II7 
ii u, 
II 
C3II7) 
C3II7 r N, 
II 
CH3 ] 
C21I5 N. 
C5Hn 
CII3) 
H > n, 
II 
CII3 L N, 
II 
CII3 ) 
ch3 In. 
ch3 
671. What is the assumed constitution of the salts of the alka- 
loids ? 
672. Describe the treatment in cases of poisoning by alkaloids. 
673. Give the process for the preparation of llydrochlorate of 
Morphine. In what form does morphine occur in opium? 
674. IIow is Acetate of Morphine prepared? 
675. What plan is adopted for preventing the decomposition of 
the official solutions of morphine? 
676. Mention the analytical reactions of morphine. 
677. In addition to the reactions of morphine, what test may be 
employed in searching for opium in a liquid or semi-fluid material ? 
678. IIow is Apomorphine prepared, and what are its properties? 
679. Describe the relation of morphine to codeine. 
QUININE, OR QUINIA. 
Formula C20II24N2O2,3II2O. Molecular weight 378. 
Source.—Quinine (Quinina, U. S. P.) and other similar alkaloids 
exist in cinchona-bark as kinates. In the yellow bark (Cinchona 
Flam, U. S. P., from Cinchona calisaya) chiefly quinine is present; 
in the pale bark (Cinch nice Pallidce Cortex, B. P., chiefly from C. 
officinalis) other alkaloids are more frequently found; while in the 
red bark (Cinchona Rubra, U. S. P.) these alkaloids occur in irreg- 
ular proportions. 
Under Cinchona the United States Pharmacopoeia recognizes “ the 
bark of any species of Cinchona containing at least 3 per cent, of 
its peculiar alkaloids.” 
Extraction of the Mixed Alkaloids.—Take 750 grains of finely 
powdered bark. Make it into a paste with milk of lime (slaked 
lime about 400 grains and water about 4 ounces). Dry the mixture 
over a water-bath. Powder the residue and place the whole in a 
cylindrical percolator. Pour in 3J fluidounces of chloroform. When, 
after standing, packing is complete, allow percolation to commence 
and to proceed slowly. After a time pour 3$ fluidounces more chloro- 
form into the percolator. When percolation has ceased transfer the 
percolate to a retort, and add nearly half an ounce of water and 
enough dilute sulphuric acid to make the mixture acid to test-paper. 
Recover the chloroform by distilling from a water-bath, and allow 
the residue to cool; filter. To the filtrate, which contains the alka- 384 
THE ALKALOIDS. 
loids as acid sulphates, add ammonia in slight excess. Collect the 
precipitated alkaloids on a filter, wash, and dry in the air or over a 
dish of sulphuric acid covered by a bell-jar. (For the separation of 
alkaloids see Index, “ Dr. Yrij’s process," an operation which should 
not be attempted at this stage of study.) 
Process for Sulphate.—Sulphate of quinine (Quinines Sulphas, 
U. S. P.) may be prepared by treating the yellow bark with dilute 
hydrochloric acid, precipitating the resulting solution of hydro- 
chlorate of quinine by soda, and redissolving the precipitated quinine 
in the proper proportion of hot dilute sulphuric acid. This, the com- 
mon commercial sulphate, crystallizes out on cooling in silky acicular 
crystals, one molecule containing two atoms of quinine (2C20If24N2O2), 
one of sulphuric acid (II2S04), and seven of water of crystallization 
(7H20). 
In the process of the former United States Pharmacopoeia 
(1870) lime was used instead of soda, the precipitated quinine 
dissolved in boiling alcohol, the latter recovered by distillation, 
the residual quinine neutralized by diluted sulphuric acid, the 
solution treated with animal charcoal, filtered while hot, set 
aside to crystallize, and recrystallized if necessary. 
Sulphate of quinine, the common or so-called disulphate (C20II24N2- 
02)2,I12S04,8H20, is only slightly soluble in water; on the addition 
of dilute sulphuric acid the so-called neutral sulphate, or soluble 
sulphate (Quinince Bisulphas, U. S. P.; C20II24N2O2,II2SO4,7H2O), is 
formed, wdiich is freely soluble. The latter salt may be obtained in 
large rectangular prisms.* An acid sulphate (C20H24N2O2,21I2SO4,- 
7II20) also exists. 
The ordinary disulphate of quinine is more soluble in alcohol or 
alcoholic liquids than in wTater. The citrate of iron and quinine 
(Ferri et Quinince Citras, U. S. P.) is the well-known scale com- 
f>ound. It is made by dissolving ferric hydrate, prepared from 
erric sulphate, and quinine, prepared from the sulphate, in solution 
of citric acid ; the liquid, evaporated to a syrupy consistence and 
dried in thin layers on glass plates, yields the usual greenish-yellow 
scales (vide p. 151). 
Quinince Valerianas, U. S. P., may be made by dissolving precipi- 
tated quinine in warm aqueous solution of valerianic acid and setting 
aside to crystallize. Its formula is c20h24n2o2,c5ii]0o2,h2o. 
Basic Citrate of Quinine has the formula (C20Il24N2O2)2,II3C6II5O7,- 
* We do not know whether or not these sulphates are ordinary sul- 
phates, the hydrogen of the acid going over to the quinine molecule, 
nor whether or not the quinine molecule is univalent or bivalent; hence 
we cannot say whether the common sulphate or the soluble sulphate is, 
in constitution, the neutral sulphate. In the above paragraph the 
names disulphate, neutral sulphate, acid sulphate, indicate nothing more 
than that the first sulphate contains in one molecule two atoms (chem- 
ical atoms) of quinine to one of sulphuric acid, the second one of each, 
and the third two of acid to one of quinine. QUININE. 
385 
5H20. Other citrates contain three molecules of quinine to two of 
citric acid, and one of quinine to one of citric acid. 
Quinines Hydrohromas, U. S. P., has the formula C20II21N2O2,IIBr,- 
Quinince Hydrochloras, U. S. P., has the formula C,0IL,N,0.,,IIC1,- 
2II20. 
Reactions. 
First Analytical Reaction:—To a solution of quinine or its 
salts in acidulated water add fresh chlorine-water, shake, and 
then add solution of ammonia; a green coloration (thalleiochin, 
or dallfiocliin) is produced. Bromine-water or bromine-vapor 
may be used instead of chlorine. 
Second Analytical Reaction.—Repeat the foregoing reaction, 
but precede the addition of solution of ammonia by that of 
solution of ferrocyanide of potassium; an evanescent red 
coloration is produced (Livonius and Vogel). 
Third Analytical Reaction.—To an aqueous solution of a 
soluble salt of quinine add solution of oxalate of ammonium; 
a white crystalline precipitate of oxalate of quinine falls. It 
is soluble in acids. If the solution to be tested be made from 
ordinary sulphate of quinine, excess of the latter should be 
added to water very faintly acidulated with sulphuric acid, 
and the undissolved crystals removed by filtration. 
Fourth Analytical Reaction.—A saturated aqueous solution 
of any neutral salt of quinine is made by dissolving so much 
of the salt in hot water as that some shall separate when the 
mixture has cooled to about 60° F. After standing for some 
time, filter. To one volume of the filtrate one-half volume of 
water-washed ether is added, and then ammonia in slight ex- 
cess. After agitation and rest for fifteen minutes all alkaloid 
precipitated by the ammonia will have dissolved. 
Note.—In the case of quinidine salts well-defined crystals will ap- 
pear at the junction of the aqueous and ethereal layers, especially 
after standing. In the case of cinchonidine salts a thick layer of 
small crystals makes its appearance at once, whilst in the case of 
cinchonine salts the undissolved alkaloid is enough to make the 
ethereal layer nearly solid. 
Fifth Analytical Reaction.—Formation of Iodo-sulphate of 
Quinine. Dissolve sulphate of quinine in weak spirit of wine 
slightly acidulated with sulphuric acid, and add an alcoholic 
solution of iodine; a black precipitate forms. Allow the pre- 
cipitate to settle, pour away the fluid, wash once or twice with 
alcohol, and then boil with alcohol; on cooling, minute crystals 
separate having the optical properties of the mineral tourma- 
line. This iodo-sulphate is sometimes termed Herapathite, 386 
THE ALKALOIDS. 
from the name of its discoverer. It is so slightly soluble in 
alcohol that by its means quinine can be separated from its ad- 
mixture with the other cinchona alkaloids. According to Jor- 
gensen, it has the formula 4C2oH24N202,3II.2S04,2III,I4,ceII20. 
Sixth Analytical Reaction.—Prepare a saturated solution of 
ordinary sulphate of quinine in water at about 00° F., and add 
to 5 volumes of that solution 7 volumes of solution of ammo- 
nia (sp. gr. 0.96). The alkaloid which at first precipitates 
redissolves upon slight agitation if the sulphate of quinine is 
free from anything but traces of other cinchona alkaloids. 
If, however, more than traces of quinidine, cinchonidine, and 
cinchonine salts be present a permanent precipitate remains. 
This is Kerner’s method of testing sulphate of quinine for 
other cinchona alkaloids. It turns upon the fact that the 
solubility of the sulphates of the cinchona alkaloids in water 
is in the opposite order to the solubility of the alkaloids them- 
selves in solution of ammonia. 
Other Characters.—Concentrated sulphuric acid dissolves 
quinine with production of only a faint yellow color, which dis- 
tinguishes it from salicin. Quinine and its salts, heated on 
platinum foil, burn entirely away. Most salts of quinine 
when in solution have a beautiful blue fluorescence. They 
twist the ray of polarized light to the left. Quinine is soluble 
in alcohol, ether, benzol, and chloroform. Ordinary quinine sul- 
phate is insoluble in chloroform, and but slightly soluble in 
water. Its solubility in chloroform is increased by the pres- 
ence in solution of quinidine and cinchonine sulphates (Pres- 
cott), and its solubility in water is decreased by the presence in 
solution of ammonium sulphate (Carles). The slight solubility 
of its sulphate and iodo-sulphate in water distinguishes quinine 
from the other cinchona alkaloids, including the “ amorphous 
alkaloid,” or “quinoidine.” 
Quinidine or Quinidia (C2pTI24N202, the Conquinine or Conchinine 
of Hesse) is an isomer of quinine. Its salts are fluorescent, and <rive 
thalleioquin with chlorine- or bromine-water and ammonia. They 
twist the ray of polarized light to the .right. Quinidine is insoluble 
in waiter and sparingly soluble in ether (see Quinine, 4th Analytical 
Iteaction). It is soluble in alcohol, benzol, and chloroform. It is 
less soluble than quinine in ammonia, 5 volumes of a saturated aque- 
ous solution of its ordinary sulphate requiring 60 to 80 volumes of 
ammonia solution (sp. gr. 0.96). Its sulphate (Quinidince Sulphas, 
U. S. P.; 2C2JI24N202,1I2S04,21I.20) is more soluble in water and 
chloroform than the sulphate of quinine. Tartrate of quinidine is 
soluble in water. The hydriodate is insoluble in water and weak 
spirit, and occurs as sandy crystals. The hydriodates of the other 
cinchona alkaloids, though more soluble than quinidine hydriodate, QUININE. 
387 
are sometimes precipitated from neutral concentrated solutions as 
amorphous or semi-liquid precipitates. These, however, are soluble 
in weak spirit. “ If 0.5 gm. each of sulphate of quinidine and of 
iodide of potassium (not alkaline to test-paper) be agitated with 10 
c.c. of water at about 60° C. (140° F.), the mixture then macerated 
at 15° C. (59° F.) for half an hour, with frequent stirring, and fil- 
tered, the addition, to the filtrate of a drop or two of water of am- 
monia should not cause more than a slight turbidity (abs. of more 
than small proportions of cinchonine, cinchonidine, or quinine).”— 
U. S. P. 
Cinchonidine or Cinchonidia (C20II24N2O).—When perfectly pure, 
salts of cinchonidine do not give thalleioquin and are not fluorescent. 
Even good commercial salts, however, nearly always give both reac- 
tions. Salts of cinchonidine twist the polarized ray to the left. 
Cinchonidine is insoluble in water and nearly so in ether (see 
Quinine, 4th Analytical Reaction). It is soluble in alcohol, benzol, 
and chloroform. It is less soluble in ammonia solution than quinine, 
five volumes of a saturated aqueous solution of cinchonidine sulphate 
requiring about 80 volumes of ammonia solution (sp. gr. 0.96). It 
is true that cinchonidine is dissolved as readily as quinine if excess 
of strong ammonia is quickly mixed with the solution of a salt of 
cinchonidine; but from such a solution cinchonidine soon crystallizes, 
while quinine remains dissolved for many hours. Sulphate ( Cincho- 
nidince Sulphas, U. S. P. (C20H24N2O)2,lI2SO4,3H2O) and hydriodate 
of cinchonidine are soluble in water, but the sulphate, like quinine 
sulphate, is insoluble in chloroform. Tartrate of cinchonidine is in- 
soluble in water, and in this form cinchonidine is usually separated 
from neutral solutions containing the other cinchona alkaloids 
except quinine. 
Cinchonine or Cinchonia (C20II24N.,O) (Cinchonina, U. S. P.) is an 
isomer of cinchonidine. When quite pure its salts are not fluores- 
cent and do not give thalleioquin. As in the case of cinchonidine, 
even good commercial specimens of cinchonia salts nearly always 
give both reactions. Cinchonia salts twist the polarized ray to the 
right. Cinchonine is insoluble in water and nearly so in ether (see 
Quinine, 4th Analytical Reaction). It is soluble in chloroform, 
benzol, and alcohol. Chloroform containing one-fourth of its 
weight of 95-per cent, alcohol dissolves cinchonine much more 
readily than either alcohol or chloroform alone. Cinchonine is 
insoluble in ammonia solution. Sulphate (Cinchonina’, Sidphas, 
U. S. P.) (C20H24N20)2,II2S04,2H20, tartrate, and hydriodate of cin- 
chonine, are soluble in water, and the sulphate, like sulphate of 
quinidine, is soluble in chloroform. In mixtures of cinchona alka- 
loids this alkaloid is precipitated by alkali after the others have 
been successively removed by ether, tartrate of sodium, and iodide 
of potassium. 
Cinchonine heated with strong potash or soda yields an oily alka- 
loid termed chinoline (C9H7N), a body which exists in coal-tar, and 
which may be obtained artificially (Skraup) by the action of caustic 
potash on a mixture of nitrobenzine and aniline in the presence of 
glycerin. It forms crystalline salts with acids. 388 
THE ALKALOIDS. 
u Quinoidine" or 11 Quinoidia," or the “Amorphous Alkaloid” 
(Chinoidin, U. S. P.).—Cinchona-barks generally contain some alka- 
loid isomeric with quinine, which, like quinine, is soluble in ether, but 
the ordinary sulphate und iodo-sulphate of which are not crystalline 
and are soluble. These salts are semi-solid, resinous-looking sub- 
stances. The iodo-sulphate is used in Dr. Vrij’s method for the 
separation of mixed alkaloids (see Index). Quinoidine is usually 
obtained along with quinine, etc. from the mixed alkaloids by ether, 
and remains in the mother-liquor, from which it is precipitated by 
an alkali. If quinoidine be triturated with boiling water, the liquid, 
after filtration, should be clear and colorless, and should remain so 
on the addition of an alkali (abs. of alkaloidal salts). On ignition, 
quinoidine should not leave more than 0.7 per cent, of ash. 
Cinchovatine or Cinchovatia occurs in a particular variety of cin- 
chona-bark. Quinicine or Quinicia and Cinchonicine or Cinchoni- 
cia are alkaloids produced by the action of heat on quinine or qui- 
nidine and on cinchonine or cinchonidine respectively. They also 
are isomers—Hesse says polymers—of the parent alkaloids. Both 
yield ordinary salts. Quiniretin is the name given to the brown or 
reddish-brown indifferent substance into which quinine in aqueous 
solution is converted when exposed to much light. 
Quinamine or Quinamia (C20H26N2O2) is a fifth cinchona alkaloid 
obtained by Hesse in 1872 from the bark of Cinchona succirubra. 
Its solution is not fluorescent and does not give thalleioquin. The 
same chemist announces the presence in cinchona of a sixth alka- 
loid, cinchamidine (C20II26N2O). 
Cupreine, homoquinine, or ultraquinine are names given to an 
alkaloid existing in the bark of a Remijia (allied to Cinchona), and 
termed cuprea-bark. It closely resembles quinine, but it is spar- 
ingly soluble in ether. 
STRYCHNINE, OR STRYCHNIA. 
Formula C21H22N202. Molecular weight 334. 
Source.—This alkaloid (Strychnina, U. S. P.) exists, to the extent 
of 0.2 to 0.5 per cent., in the seed of Strychnos Nu.x Vomica (Nux 
Vomica, U. S. P.), also (Shenstone) in minute quantity in the bark 
of the Nux Vomica tree (false Angostura-bark), and to 1.0 or 1.5 
per cent, in St. Ignatius’s bean (Strychnos Ignatia) (Tgnatia, U. S. P.), 
chiefly in combination with strychnic or igasuric acid, or, after slight 
fermentation when moistened, with lactic acid. 
Process.—According to the British official process for its prepara- 
tion, the nuts, disintegrated by subjection to steam, and, after drying, 
grinding in a coffee-mill, are exhausted with spirit, the latter removed 
by distillation, the extract dissolved in water, coloring and acid mat- 
ters precipitated by acetate of lead, the filtered liquid evaporated to 
a small bulk, the strychnine precipitated by ammonia, the precipitate 
washed, dried, and exhausted with spirit, the spirit recovered by dis- 
tillation, and the residual liquid set aside to crystallize. Crystals STRYCHNINE. 
389 
of strychnine having formed, the mother-liquor (which contains the 
brucine of the seeds) is poured away, and the crystals of strychnine 
washed with spirit (to remove any brucine) and recrystallized. 
In the U. S. P. (1870) process the rasped Nux Vomica is exhausted 
by very dilute hydrochloric acid, milk of lime added to the evap- 
orated decoction to decompose the hydrochlorate of strychnine, the 
precipitated and dried mixture of strychnine and lime treated with 
diluted alcohol to remove brucine, and then with strong, hot alcohol 
to dissolve out strychnine; the alcohol having been recovered by dis- 
tillation, the residual impure strychnine is dissolved in very dilute 
sulphuric acid, the solution decolorized by animal charcoal, evap- 
orated, and set aside to crystallize, the crystals of sulphate of strych- 
nine (Strychnince Sulphas, U. S. P.; 2C21H2.2N,02,H2S04,7H20; Cole- 
man, 6II20) redissolved in water, ammonia added to precipitate pure 
strychnine, and the latter dried. It is soluble in about 40 parts of 
water. 
Properties.—Strychnine occurs “ in right square octahedrons or 
prisms, colorless and inodorous; sparingly soluble in water, but 
communicating to it its intensely bitter taste; soluble in boiling 
rectified spirit and in chloroform, but not in absolute alcohol or in 
ether.” 
Reactions. 
First Analytical Reaction.—Place a minute particle of 
strychnine on a white plate, and near to it a small fragment of 
red chromate of potassium; to each add one drop of concen- 
trated sulphuric acid; after waiting a minute or so for the 
chromate to fairly tinge the acid, draw the latter, by a glass 
rod, over the strychnine spot; a beautiful purple color is pro- 
duced, quickly fading into a yellowish-red. The following 
oxidizing agents may be used in the place of the chromate: 
puce-colored oxide of lead, fragments of black oxide of man- 
ganese, ferrideyanide of potassium, or permanganate of potas- 
sium. 
This reaction is highly characteristic: a minute fragment dissolved 
in much dilute alcohol—or, better, chloroform—and one drop of the 
liquid evaporated to dryness on a porcelain crucible-lid or other white 
surface, yields a residue which immediately gives the purple color on 
being oxidized in the manner directed. 
Other Reactions.—Strong sulphuric acid does not decompose strych- 
nine even at the temperature of boiling water, a fact of which advan- 
tage is taken in separating strychnine from other organic matter for 
purposes of toxicological analysis. Sulphocyanide of potassium 
produces, even in dilute solutions of strychnine, a white precipitate, 
which under the microscope is seen to consist of tufts of acicular 
crystals. Strong nitric acid does not color strychnine in the cold, 
and on heating only turns it yellow. 
The Physiological Test.—A small frog placed in an ounce of water 
to which of a grain of a salt (acetate) of strychnine is added is in THE ALKALOIDS. 
two or three hours seized with tetanic spasms on the slightest touch, 
and dies shortly afterward. 
Strychnine has an intensely bitter taste. Cold water dissolves only 
Tpoo part, yet this solution, even when largely diluted, is distinctly 
bitter. Alcohol is a somewhat better solvent. "The salts of the alka- 
loid are more soluble. The Liquor Strychnia?, B. P., contains four 
grains of strychnine to the ounce, the solvent being three parts water, 
one part spirit, and a few minims (6 per ounce) of hydrochloric acid 
(rather more than sufficient to form hydrochlorate of strychnine). A 
syrup of Phosphates of Iron, Quinine, and Strychnine is official (Syr- 
upus Ferri, Quinines, et Strychnines Phosphatum). It contains 1 part 
of strychnine in 2500. 
Brucine, or Brucia (C23II26N?04,4H20), is an alkaloid accom- 
panying strychnine in Nux Vomica and St. Ignatius’s bean to the 
extent of about 0.5 per cent. It is readily distinguished by the 
intense red color produced when nitric acid is added to it. 
Igasurine, once supposed to be a third alkaloid of nux vomica, 
has been shown by Shenstone to be only a mixture of brucine and 
strychnine. 
Curarine (C10II15N), the active principle of the arrow-poison 
termed urari, ourari, wourali, or woorara, prepared from a Stryck- 
nos, resembles strychnine in giving color by oxidation, but the color 
is more stable. Iodide or platino-cyanide of potassium does not 
with curarine afford precipitates which crystallize from alcohol like 
those of strychnine. Curarine also is soluble in water. Unlike 
strychnine, curarine is reddened by sulphuric acid ; it, also, is not 
dissolved out by ether from an acid or alkaline liquid. Curari 
appears to vary much in strength and quality. It is probably a 
mixture of vegetable extracts. 
Distinction of Brucine from Morphine.—The red coloration pro- 
duced by the action of nitric acid on brucine is distinguished from 
that yielded by morphine by the action of reducing agents (such as 
stannous chloride, hyposulphite of sodium, sulphydrate of sodium), 
which decolorize the morphine red, but change that of the brucine to 
violet and green (Cotton). 
Distinction of Free Alkaloids or their Salts from Each Other.— 
I his is accomplished by remembering the appearance and other 
physical characters of the substances as met Avith in pharmacy, the 
effect of heat, the action of such solvents as water, alcohol", and 
ether, the influence of strong and diluted acids, strong and weak 
alkalies, oxidizing agents, chlorine-water and ammonia, and pther 
reagents. (See annexed Tables, I. and II.) 
680. What alkaloids are more or less characteristic of the differ- 
ent varieties of cinchona-bark? In what form do they occur? 
681. By what method is Disulphate of Quinine obtained? 
682. (Jive the characters of disulphate of quinine. 
683. Describe the tests for quinine. 
QUESTIONS AND EXERCISES. To face page 391.] 
I. TABLE FOB THE IDENTIFICATION OF THE FOLLOWING ALKALOIDS, ACIDS, ETC. 
(Compiled by A. Senieii, M. 1).) 
Morphine. 
Brucine. 
Salicin. 
Strychnine. 
Quinine. 
Quinidine. 
Cinchonine. 
ClNCIIONIDINE. 
i Sulphuric. 
ACIDS, -j Hydrochloric. 
( Phosphoric. 
Acetic. 
Meconic. 
Citric. 
If Morphine, Brucine, Salicin, and Strychnine are 
absent, make a saturated solution in 
hot water 
To a small quantity on a 
If no Morphine or Brucine, 
moisten a small quantity on 
a white plate with strong 
sulphuric acid. 
and cool down to about 60° F., removing the crys- 
tals which have deposited by filtration. If the sub- 
Make a solution with a slight excess of 
Make a neutral solution, di- 
white plate add strong nitric 
stance is an alkaloid or an acid salt, 
it must be 
nitric acid, divide it into three portions, and 
vide it into two portions, and 
acid. 
neutralized. To one volume of this solution in a 
test-tube add exactly half a volume of ether and 
test as follows 
— 
test as follows:- 
then ammonia solution in slight excess. Agitate 
and set aside for a quarter of an hour 
An Orange 
A Red Color. 
A deep red 
No color, or 
Precipitate entire- 
A crystalline layer 
Precipitate 
First por- 
Second por- 
Third por- 
First por- 
Second por- 
Color, de- 
To a few 
color — Salt- 
only a slight 
l) soluble in the 
between the ethereal 
insoluble 
tion. 
tion. 
tion. 
tion. 
tion. 
colorized by 
grains in a 
cin. 
color. 
ether. 
and aqueous solu- 
in ether — 
Add BaCI2. 
Add AgN03. 
Boil for a 
Add neutral 
If no ace- 
SnCl2, Na2S2 
test-tube add 
Confirm by 
Drawamois- 
To a portion of 
tions. 
Cinc ho- 
A precipitate 
A precipitate 
time and then 
Fe2Cl6- A red 
tic or meco- 
03, or NallS 
a drop or two 
boiling the 
tened crystal 
the saturated 
To a portion of 
nine. 
= Sulphuric 
= Hydro- 
add a fe w 
color indicates 
nic acid, add 
II 
is 
** 
of HNOs; 
substance 
of K2Cr207 
aqueous solution 
the aqueous solu- 
Confirm 
Acid. 
chloric Acid. 
drops of an 
acetic or me- 
AgN03. 
Confirm by— 
warm to boil- 
with water to 
across the 
add rather more 
tion add Na2C4- 
by other 
excess of solu- 
conic acid. 
Precipitate 
Fe2Cl6(neut.), 
ingand dilute 
which has 
acid film when 
than an equal bulk 
I1406 and agitate. 
reactions 
tion of molyb- 
Distinguish. 
(white, with a 
which gives 
with water; 
been added a 
a transient 
of ammonia solu- 
A bulky crystalline 
(see Cin- 
date of am- 
Decolorized by 
tendency to 
with m 0 r- 
then add a 
few drops of 
play of colors, 
tion (sp. gr. 0.96) 
precipitate = Cin- 
chonine). 
monium in 
boiling=Aceti'c 
darken) sol- 
phine or its 
few drops of 
dilute 1I2S04. 
violet to red 
and agitate. The 
chonidine. 
HN O3, and 
A cid. 
uble in HNO3 
salts a blue 
stannous chlo- 
Then make 
= Strychnine. 
precipitate dis- 
Confirm by other 
boil. A yel- 
Not decolor- 
= Citric Acid. 
color. 
ride. 
solution alka- 
solves completely 
reactions (see Cin- 
low pulveru- 
ized by boil- 
Confirm by 
HIOs is de- 
A violet col- 
line and ex- 
= Ordinary Sid- 
chonidine). 
lent precipi- 
ing= Meconic 
adding CaCl2 
composed by 
or = Brucine. 
amine for glu- 
phate of Quinine. 
If no precipitate 
tate = Phos- 
Acid. 
to a neutral 
morphine or 
cose. 
If precipitate 
or only a trace, add 
plioric Acid. 
cone, solution 
its com- 
does not dissolve 
to another portion 
and boiling, 
pounds, with 
completely, add to 
of the aqueous so- 
when a white 
liberation of 
another portion of 
lution KI. A heavy 
precipitate of 
iodine, which 
the aqueous solu- 
white precipitate 
citrate of cal- 
may be re- 
tion (NH4)2C204 
= Quinidine. 
cium sepa- 
cognized by 
and agitate (no 
If the precipitate 
rates. 
starch. 
precipitate at once 
with ordinary sul- 
phate of quinine). 
be semi-liquid, it 
* Strychnine 
idine or other alka- 
of commerce 
A bulky crystal- 
loids, the hydrio- 
often gives an 
orange or red 
line precipitate — 
Quinine. 
dates of which are 
soluble in weak 
contamination 
Confirm by other 
spirit. 
with brucine. 
reactions (see 
Quinine). II. TABLE FOR THE QUALITATIVE ANALYSIS OF ORDINARY SCALE COMPOUNDS. 
(Compiled by A. Senier, M. D.) 
To face page 391.] 
f Quinine. Cinchonine. 
ALKALOIDS. •! Quinidine. Cinciionidine. 
[Beberine. Strychnine. 
Pyrophosphoric. 
02 Hypophosphorous (generally converted into pyrophosphoric). 
Q , Sulphuric. 
3 Hydrochloric (as a contamination). 
<1 Tartaric. 
Citric. 
0 
S . f Ammonium (often as 
S | a contamination), 
ti co -i Ferric Iron. 
g j Potassium. 
[Sodium. 
M 
Dissolve a portion in II2O, and add NH4IIO cautiously (Precipitate = Alka- 
loids (except Strychnine) and sometimes Fe26HO). Agitate the mixture with a 
little ether, and separate, by means of a pipette, the ethereal solution, aqueous 
solution, and insoluble precipitate. 
Ignite a small quantity of the scale. Heat the ash with HNO3, 
and add to an excess of solution of ammonium molybdate in HNO3, 
and boil. 
Ammonium.—-Boil aqueous 
solution of scale with KHO 
and test vapor for NH3. 
Filter and dissolve precipi- 
tate in HC1, and test the so- 
lution ior Iron by K4FeCy6, 
KCyS, etc. 
Ethereal 
Solution. 
Insoluble 
Precipitate. 
Aqueous 
Solution. 
A Yellow Precipitate. 
No Yellow 
Precipitate. 
May contain quinine, quinidine, or 
heberine. To solution in a test-tube 
add II2O, very slightly acidulated with 
IIC2II3O2 and boil, burning off the ether. 
To a portion of the acetic solution 
Is cinchonine, 
cinchonidine, or 
Fe26HO. 
Saturate a drop 
or two of acetic acid 
May contain 
strychnine. Agi- 
tate with CIICI3 
and separatechlor- 
oformic solution. 
Evaporate chloro- 
formic solution, 
and moisten resi- 
Pyrophosphoric or hypophos- 
phorous acid. Precipitate some 
of the aqueous solution with 
1 KHO, filter, neutralize with 
HNO3 and add AgNOs. 
Precipitate some of the aqueous solu- 
tion with KHO, filter, and add to a por- 
tion of the filtrate a slight excess of 
HNO3 and divide into two parts. To 
one add BaCl2 (precipitate = Sulphuric 
Acid). To the other add AgN03 (pre- 
cipitate = Hydrochloric Acid). Neutral- 
ize another portion of the KHO filtrate 
Ignite a small quantity of 
the scale, and moisten the 
residue with water. Test 
moistened residue with lit- 
mus-paper. If alkaline, ex- 
amine for potassium and 
sodium by the color im- 
parted to flame, and for po- 
tassium by HC1 and PtCL. 
NII4IIO. 
with the precipi- 
tate, and to part 
White pre- 
cipitate solu- 
ble in nitric 
acid = Pyro- 
pho sp ho ri c 
White to 
black precipi- 
tate, soluble in 
nitric acid = 
Hw0ph08 - 
Green Color 
No Green Color. 
of the solution add 
Na2C4H40g, when 
due with concen- 
trated H2SO4. Draw 
with HNO3 and add AgN03. 
(thalleioquin). 
a precipitate occurs 
in the case of cin- 
chonidine, and no 
precipitate in that 
of cinchonine. 
across the acid film 
a small moistened 
crystal of K2Cr207 
when a transient 
play of colors — 
violet to red = 
strychnine. No 
colors = no strych- 
nine. In case of 
doubt add NH4HO 
to original solu- 
tion. Agitate with 
chloroform, and 
proceed as before. 
Precipitate 
Precipitate 
Solution is fluor- 
To a portion of 
Acid. 
phorous Acid. 
Gray to Black. 
White. 
escent, and con- 
tains either qui- 
nine or quinidine. 
Concentrate the re- 
mainder of the so- 
lution and divide 
into two parts. To 
one add KI, and 
to the other add 
(NH4)2C204. 
KI precipitates 
quinidine, not qui- 
nine. 
(NH4)2C204 pre- 
cipitates quinine, 
not quinidine. 
For another 
method, see the 
third division of 
the annexed Table 
(I.) for alkaloids, 
using 40 or 50 
grains of material. 
the acetic solution 
add KHO, a yel- 
lowish-white pre- 
cipitate= Beberine. 
Add very little 
NH4HO (not suffi- 
cient to dissolve 
the whole precipi- 
tate) and heat. A 
silver mirror= Tar- 
taric Acid. 
CaCl2 and Ca2IIO 
precipitate neutral 
solution (if concen- 
trated) in the cold, 
the precipitate re- 
dissolving on boil- 
ing. 
Citric acid gives 
no mirror. CaCl2 
and Ca2HO do not 
precipitate citric 
acid in the cold, 
but upon boiling 
(if solution be 
sufficiently concen- 
trated) precipita- 
tion occurs. 
Confirm Tartaric or Citric Acid.—To slightly acidified KHO filtrate 
add NH4HO in slight excess and considerable quantity of NH4CI and 
CaC]2. Tartrates are precipitated completely in the cold with agita- 
tion and rest for about ten minutes. To the solution (or filtrate if 
tartrates are present) add three volumes of spirit of wine, when 
Citrates are precipitated. If sulphates have been found, disregard 
slight precipitate with spirit of wine. ACONITINE. 
391 
684. How is the adulteration of disulphate of quinine by saliein 
detected ? 
685. Show how the sulphates of quinine or cinchonine may be 
proved to be present in commercial quinine. 
686. How are cinchonine and quinine distinguished from morphine? 
687. Whence is strychnine obtained? 
688. Describe the official process for the isolation of strychnine. 
689. Give the characters of strychnine. 
690. Enumerate the tests for strychnine, and describe their mode 
of application. 
691. By what reagent is brucine distinguished from strychnine? 
692. Distinguish between brucine and morphine. 
693. By what general methods would you distinguish common 
alkaloids from each other? 
Analytical Exercises.—Analyze small quantities of alkaloids, 
their salts, and various “scale” compounds by aid of the annexed 
Tables, I. and II. 
ALKALOIDS OF LESS FREQUENT OCCURRENCE. 
Aconitine, Aconitine, or Aconitia is an alkaloid obtained from 
aconite (Aconitum Napellus) leaves (Aconiti Folia, B. P.) and root 
(Aconitum, U. S. P.). The alkaloid itself is only slightly soluble in 
water; it occurs in the plant in combination with a vegetable acid, 
forming a soluble salt. 
Process.—The process for the preparation of Aconitine, B. P., con- 
sists in dissolving out the natural salt of the alkaloid from the root 
by rectified spirit, recovering the latter by distillation, mixing the 
residue with water, filtering, precipitating the aconitine by ammonia, 
drying the precipitate and digesting it in ether (in which some of 
the accompanying impurities are insoluble), recovering the ether by 
distillation, dissolving the dry residue in the retort in water acid- 
ulated by sulphuric acid, again precipitating the alkaloid by am- 
monia, and finally washing and drying. 
Properties.—Aconitine usually occurs as a white powder, but lias 
been obtained and studied in the crystalline state by Groves, Wright, 
and others. It is soluble in 150 parts of cold water, 50 of hot, and 
is much more soluble in alcohol and ether. It is one of the most 
violent poisons known. “ When rubbed on the skin it causes a 
tingling sensation, followed by prolonged numbness.” 
The thousandth part of a grain on the tip of the tongue produces, 
after a minute or so, a characteristic tingling sensation and numb- 
ness : larger quantities rubbed into the skin cause numbness and 
loss of feeling. Oil of vitriol turns it of a yellowish, and after- 
ward dirty-violet, color. 
According to Wright, who, in conjunction with Groves and Wil- 
liams, worked by aid of grants from the British Pharmaceutical Con- 
ference, Aconitum napellus yields crystalline aconitine, C;U1I4;,N012, 392 
THE ALKALOIDS. 
crystalline pseud-aconitine, C36H49NO)2, and a non-crystalline alka- 
loid. 
The tuberous roots of Aconitum ferox and other species constitute 
the bisk or bitch of India (Aconiti ferocis Radix, P. I.). It chiefly 
contains the variety of aconitine termed pseud-aconitine. Some of 
the aconitine of pharmacy is pseud-aconitine. According to Paul 
and Kingzett, the alkaloid of Japanese aconite has the formula 
C29II4:!N09, while Wright and Menke state that the formula is 
C6fil l88N202, and name it japaconitine. 
Aconitum heterophyllum, Atis, or A tecs (Aconiti heterophylli Radix, 
P. I.), contains no aconitine, but an alkaloid having the formula 
C46II74N205 (Broughton, in Pharmacogr aphid). 
Aspidospermine is an alkaloid of Quebracho bianco bark (Fraude). 
Another and different alkaloid is quebrachine (C2III2CN203) (Ilesse). 
The latter chemist has isolated four other closely-related alkaloids, 
and two from Quebracho Colorado bark. 
Atropine, or Atropia (C17II23N03), exists in the Belladonna, or 
Deadly Nightshade (Atropa belladonna; Relladounce Folia et Radix, 
U. S. P.), as soluble acid malate of atropine. 
Pi •ocess.—It is obtained in the pure state by exhausting the root 
with spirit, precipitating the acid and some coloring-matter by lime, 
filtering, adding sulphuric acid to form sulphate of atropine (which is 
somewhat less liable to decomposition during subsequent operations 
than the alkaloid itself), recovering most of the spirit by distillation, 
adding water to the residue, and evaporating till the remaining spirit 
is removed ; solution of carbonate of potassium is then poured in till 
the liquid is nearly but not quite neutral, by which resinous matter 
is precipitated; the latter is filtered away, excess of carbonate of 
potassium then added, and the liberated atropine dissolved out by 
shaking the liquid with chloroform. The latter solution, having sub- 
sided, is removed, the chloroform recovered by distillation, the re- 
sidual atropine dissolved in warm spirit, coloring-matter separated 
by digesting the liquid with animal charcoal, the solution filtered, 
evaporated, and set aside to deposit crystals. 
Solubility.—Atropine is sparingly soluble in water, the liquid giv- 
ing an alkaline reaction—more soluble in alcohol and ether. 
Tests.—Atropine solutions give with perchloride of gold a yellow 
precipitate. One drop of a dilute aqueous solution (two grains to 
the ounce) powerfully dilates the pupil of the eye. It is generally 
applied on a piece of thin tissue-paper or small disk placed between 
the eyelid and the eye. Baryta-water decomposes it into tropine 
, (C8Hj5NO) and tropic arid (09HloO3), a molecule of water being 
absorbed; hence the atropine so called would seem to be tropate of 
atropine. Indeed, Ladenburg by combining tropic acid and tropine 
has produced a base indistinguishable from atropine. The same 
chemist by removing the elements of water from tropine gets tropi- 
dine, C8II13N. This is, possibly, an intermediate member of a group 
of monamines of which others are conine, C8II15N, and collidine, 
CglljjN, the latter a product of the destructive distillation of bone- 
oil, coal, quinine, etc. BERBERINE. 
393 
Commercial atropine is said by Regnauld and V almont to be a 
mixture of true atropine with hyoseyamine. 
Preparations.—The alkaloid itself (Atropina) and its sulphate 
(Atropines Sulphas, (CnlIMN03).2H.,S04, a colorless powder soluble 
in water, made by neutralizing atropine with sulphuric acid) are 
official in the United States Pharmacopoeia. 
Beberine, Bebirine, Beberia, or Bibirina (C18H21N03), an alka- 
loid existing in the bark of Bebeeru or Bebioe (Nectandra Rodicei). 
Process.—According to the British Pharmacopoeia, it, or rather 
its sulphate, C3eII42N.!0e,II2S04 (Beberia; Sulphas, B. P.), may be 
prepared by exhausting the bark (Neetandrce Cortex, B. P.) with 
water acidulated by sulphuric acid, concentrating, removing most 
of the acid by lime, filtering, precipitating the alkaloid by ammonia, 
filtering, drying, dissolving in spirit (in which some accompanying 
matters are insoluble), recovering most of the spirit by distillation, 
neutralizing by dilute sulphuric acid, evaporating to dryness, dis- 
solving the residual sulphate in water, evaporating to the consist- 
ence of a syrup, and spreading on glass plates, drying the product 
at 140° F. Thus obtained, it occurs in thin dark-brown translucent 
scales, yellow when powdered, strongly bitter, soluble in water and 
in alcohol. It is probably not a single definite salt. 
Tests.—Alkalies give a pale-yellow precipitate of beberine when 
added to an aqueous solution of a salt of the alkaloid ; the precipi- 
tate is soluble in ether. With red chromate of potassium and sul- 
phuric acid beberine gives a black resin, and with nitric acid a yel- 
low resin. 
Buxine, from the bark of Buxus sempervirens; Pelosine, or Ciss- 
ampeline, from the root (Pareira, U. S. P.) of Chondodendron tomen- 
tosum; and Paricine, from a false Para cinchona-bark, are probably 
identical with Beberine (Fllickiger). 
Nectandrine (C20l 12:!N0,).—Drs. Maclagan and Gamgee a few years 
ago discovered this second alkaloid in Bebeeru-bark. It differs 
from beberine in fusing when placed in boiling water, in being much 
less soluble in ether, in giving with strong sulphuric acid and black 
oxide of manganese a beautiful green and then violet coloration, ami 
in having a distinct molecular weight. They gave the opinion that 
two other alkaloids exist in Bebeeru-bark. 
Berberine, or Berberia (C20IIuNO4) is an alkaloid existing in 
several plants of the natural order Berberidece (three species yield 
Indian Barberry, Berberis Cortex, P. 1.), in Calumba-root (Calumba, 
U. S. P.), Goldthread (Coptis trifolia) according to Mayer in the 
root of Coptis Suta, or Nieshnic Bitters (Captidis Radix, P. I.), an 
Indian tonic, and in many yellow woods. Hydrastis canadensis, 
Yellow-root or Golden Seal (Hydrastis, U. S. P.), contains berberine, 
though another alkaloid, hydrastine, and even a third, are said to be 
present. Xanthorrhiza apiifolia, an old American tonic, and, appa- 
rently , Xanthoxylum fruxineum, or Prickly Ash bark (Xanthoxylum, 
U. S. P.), also contain berberine. The rhizome of Menispermum cana- 
dense, Yellow Parilla or Canadian Moonseed (Menispermum, U. S. P.), 
contains, according to Maisch. a colorless alkaloid as well as ber- 394 
THE ALKALOIDS. 
bovine. The color of the tissues of these vegetables is apparently 
due to berberine, for the alkaloid itself is remarkable for its beautiful 
yellow color. 
Tests.—When a dilute solution of iodine in iodide of potassium is 
added to a solution of any salt of berberine in hot spirit, excess of 
iodine being carefully avoided, brilliant green spangles are deposited. 
The reaction is sufficiently delicate to form, according to Perrins, an 
excellent test of the presence of berberine. This iodo-compound 
polarizes light, and has other analogies with a similar quinine-salt 
termed Herapathite. 
Berberine is not an official alkaloid, but the plants in which it 
occurs are used as medicinal agents in all parts of the world. 
Process.—Berberine is readily extracted by boiling the raw mate- 
rial with water, evaporating the strained liquid to a soft extract, 
digesting the residue in alcohol, recovering the alcohol by distilla- 
tion, boiling the residue with diluted sulphuric acid, filtering, and 
setting aside; the sulphate of berberine separates out, and may be 
purified by recrystallization from hot water. The alkaloid itself is 
obtained by shaking hydrate of lead with a hot aqueous solution of 
the sulphate of berberine (Procter). 
Capsicine, or Capsicia.—M. Felletar obtained from capsicum- 
fruits (Capsicum, U. S. P.), which when ground form Cayenne Pep- 
per or African Pepper, a volatile alkaloid having the smell of coniine. 
Thresh has obtained ci’ystalline hydrochlorate and sulphate. The 
latter chemist has also succeeded in isolating the active principle of 
capsicum, which he has termed capsaicin (C9IIu02), a crystalline, 
non-alkaloidal, excessively acrid substance. Its exact chemical 
character is not yet made out. (See also Capsicin in Index.) 
Chemdonine (C19H17N303) and Ciielerythrine (C19II17N04), the 
latter identical, apparently, with sanguinarine, are two alkaloids 
occurring in Celandine (Chelidonium, U. S. P.), associated with 
citric, malic, and chelidonic (C7II406) acids. 
Cocaine, or Cocaina (C16TII9N04) is an alkaloid of Erythroxylon 
coca (Erythroxylon, U. S. P.), the leaves of which are said to be a 
powerful restorative to the human system. 
Colchicine, or Colchicia, the active principle of Colchicum 
autumnale (Colchici Radix; Colchici Semen, U. S. P.), is said 
to be an alkaloid, though some investigators think it has more 
of the characters of a neutral substance and give it the name Col- 
chicin. Teisel says it may be crystallized from chloroform, llertel 
gives it the formula C17II23N06, and states that ebullition with acid- 
ulated water converts it into colcliicein, C17IIS1N05,21I20. It needs 
further examination. The most active medicinal preparation is an 
extract made from the fresh seeds by digestion in large volumes of 
alcohol of at least 90 per cent., and subsequent digestion of the 
marc in hot water. The extracts left on evaporating the two fluids 
separately are to be carefully mixed (Mols). 
Coniine, Conicine, Cicutine, Conia, or Conylia. Formula 
C81I17N (Hofmann).—This alkaloid is a volatile liquid occurring in 
hemlock (Coniinn macidatum), in combination with an acid (malic?). CORYDALINE—EMETINE. 
395 
It is not official. According to Petit, its boiling-point is 170° C., 
and its density 0.840. It forms crystalline salts. 
Process.—It may be obtained by distilling hemlock-fruit (Co- 
ilium, U. S. P.) with water rendered slightly alkaline by caustic soda 
or potash, or by similarly treating the fresh juice of the leaves, 
The alkaloid is a yellow oily liquid floating on the water that distils 
over; by redistillation it is obtained colorless and transparent. 
The salts of coniine have no odor, hut when moistened with solu- 
tion of an alkali yield the alkaloid, the strong smell of which, at 
once recalling hemlock, is characteristic. Extract of hemlock-leaves 
(Conii Folia, B. P.), to which solution of potash and boiling water 
have been added, forms the official Inhalation of Coniine (Vapor 
Conioe, B. P.). 
Tests.—Sulphuric acid turns coniine purplish-red, changing to olive- 
green, nitric acid a blood-red; perchloride of gold produces a yel- 
lowish-white precipitate, perchloride of platinum no precipitate, in 
aqueous solutions. 
Hemlock also contains methyl-coniine (C8H14)//CH3N2 ? (Kekule 
and Van Planta), and conhydrine, C8H17NO. 
According to Schiff, coniine, isomeric, at least, with the natural 
alkaloid, may he produced artificially by action of ammonia on buty- 
ric aldehyd and destructive distillation of the resulting compound. 
Corydaline, Corydamna, or Corydalia, is an alkaloid obtained 
by Wenzell from “ Turkey Corn," the tubers of Dicentra (corydalis) 
formosa. 
Daturine, or Datlria. Vide IIyoscyamine. 
Delphinine, Delpiiine, or Delphia (C24II33N02) the poisonous 
alkaloid of Stavesacre, Delphinium staphisagria (Staphisagria, 
U. S. P.). The powdered seeds of the plant are employed to kill 
the pediculi of animals. 
Ditamine (Jobst and Hesse), the Ditain of Gruppe, is the alka- 
loid of “ Dita,” or bark of Echites scholaris or Alstonia scholaris 
(Alstonice Cortex, P. I.), a reputed febrifuge. Oberlin and Schlag- 
denhauffen state that the allied Alstonia constricta contains a crys- 
talline alkaloid alstonine and unerystallizable alstonicine. Alsto- 
nine seems to he allied to strychnine. 
Duboisine, or Duboisia, is the name suggested by Gerrard for 
the alkaloidal active principle he extracted from Duboisia myopo- 
roides, unless, as he adds, the body should prove to be atropine, to 
which it is, at all events, closely allied. 
Emetine, or Emetia (C30II44N2Og, Glenard).—This alkaloid is the 
active emetic principle of the root of Cephodis ipecacuanha (Ipe- 
cacuanha, U. S. P.). It occurs in combination with ipecacuanhic 
acid. The nitrate is peculiarly slightly soluble in water (Lefort). 
In the Pulvis Ipecacuanhee et Opii, U. S. P., or “Dover's Powder” 
(Powdered Ipecacuanha, 1 part; Powdered Opium, 1 part; and 
Sugar of Milk, 8 parts), minute division of the active ingredients is 
promoted bv prolonged trituration with the sugar of milk, which is 
hard. The Indian substitute of Ipecacuanha is the dried leaf (Tylo- TIIE ALKALOIDS, 
phorce Folia, P. I.) of Tijlophora asthmatica. Its active principle has 
not been satisfactorily isolated. 
Gelsemine, or Gerseminia (CnII19N02, Sonnenschein ; c12h14no.2, 
Gerrard), is the alkaloid of Gelsemium sempervirens, or Carolina, 
Yellow Jasmine (Gelsemium, U. S. P.), in the tissues of which plant 
the gelseminic acid of Wormley and cesculin (C30II34O19), the fluo- 
rescent glucoside of the Horse Chestnut and of many other plants, 
are also present. 
Hyoscyamine, or IIyoscyamia (C17II23N03), a volatile alkaloid, 
occurs in the leaves (Hyoscyamus, U. S. P.), seed, and other parts of 
Henbane. According to Duquesnel, it is solid and crystalline. Its 
effect on the eye is similar to that of atropine. The researches of 
Buckheim point to the conclusion that hyoscyamine is the tropate 
of an alkaloid homologous with tropine (Sonnenschein). (See Atro- 
pine.) 
Sulphate of Hyoscyamine, (C17II23N03)2,II2S04, is official (IIi/os- 
cyaminoe Sulphas, U. S. P.). It is yellowish-white. 
Ladenburg also finds in henbane some hyoscine, a tropate of 
another alkaloid homologous with tropine. 
'fhe alkaloids which occur in Datura Stramonium, or Thorn- 
apple (Stramonii Folia et Semen, U. S. P.; Dhatura; Datura 
alba; Datura; Folia et Semina, P. I.), and in Duboisia myopo- 
roides, and formerly supposed to be distinct alkaloids, called re- 
spectively Daturine and Duboisine, are identical with hyoscyamine, 
and the latter is isomeric, if not identical, with atropine (Laden- 
burg.) Ordinary atropine also occurs in stramonium. Bees which 
sip from the flowers of stramonium are said to produce poisonous 
honey. 
Jervine, or Jervia (C30H46N2O3) occurs in Veratrum album, 
White Hellebore, and V. viride (U. S. P.),* American White Hel- 
lebore, the root of which is officially recognized in Great Britain 
( Veratri Viridis Radix, B. P.). Its salts are much less soluble in 
water than those of veratrine. According to Bullock, Veratrum 
viride contains still another alkaloid, veratroidine; and, according 
to Mitchell, Veratrum album also contains an alkaloid which he terms 
veratralbine. Tobien gives the formula of jervine as C27H47N208, and 
of veratroidine as C51II78N2016 or C24H37N07. According to Wright, 
Veratrum album contains jervine, C26H37N03; pseudojervine, 
C29II43NO.; rubijervine, C2fiH4;jN02; veratralbine, C2gIl43]S'05; and 
traces of veratrine, C37H63NOn. The same author finds Veratrum 
viride to contain jervine, pseudojervine, cevadine, C321I49N09, rubi- 
jervine, and traces of veratrine and veratralbine. 
Juglandine is the name given by Tanret to an alkaloidal sub- 
stance obtained from the leaves of the walnut, Juglans regia. In 
the root-bark of Juglans cinerea, or Butternut (Juglans, U. S. P.), 
* “The name Green Hellebore is sometimes applied to the drug, but 
it properly belongs to Helleborns vivid is (p. 421), which is medicinal in 
some parts of Europe.”—Hanbury. LOBELINE—PIPERINE. 
397 
Thiebaud found a bitter substance and an acid resembling chryso- 
phanie. 
Lobeline, or Lobelia.—A volatile fluid alkaloid first isolated from 
the dried flowering herb Lobelia injiata (Lobelia, U. S. P.) by Proc- 
ter. In the pure state it smells slightly of the plant, but mixed with 
ammonia it emits a strong and characteristic smell of the herb. 
With acids it forms crystalline salts. 
Lupuline is stated by Greismayer to be a liquid volatile alkaloid 
contained in hops (Hamulus lupulus). 
Nectandrixe. Vide Beberixe. 
Nicotine, Nicotixa, Nicotia, or Nicotylia, formula CI0IIUN2, 
or (C5H7)///2N2. This is also a volatile liquid alkaloid, forming the 
active principle of tobacco (Nicotiana tabacum), malate and citrate 
of nicotine being the forms in which it occurs in the leaf (Tabacum, 
U. S. P.). Its odor is characteristic; like coniine, it yields a precip- 
itate with perchloride of gold ; but, unlike that alkaloid, its aqueous 
solutions are precipitated yellowish-white by perchloride of plati- 
num. It is not official. It is also contained in pituri, a drug 
“ chewed by the natives of some parts of Australia as a stimulant 
narcotic.” 
Physostigmine, or Piiysostigma (C30II21N3O4).—An alkaloid con- 
tained in the Calabar bean (Piiysostigma, U. S. P.), the seed of 
Piiysostigma venenosum (Jobst and Hesse). A trace of it power- 
fully contracts the pupil of the eye; a small quantity is highly 
poisonous. Fraser also isolated another (but, possibly, the same) 
principle, and termed it Eserine, from Esere, the name of this ordeal- 
poison at Calabar. Salicylate of Physostigmine is official (Physos- 
tigmince Salicylas, U. S. P.), C15II21N302,C7II603. 
Pilocarpine is, apparently, the active principle of the diapho- 
retic and sialogogue Jaborandi, the leaflets of Pilocarpus pinnati- 
folius (Pilocarpus, U. S. P.). The occurrence of an alkaloid in this 
plant was first announced by Hardy, followed almost immediately 
by Byasson. A crystalline nitrate and hydrochlorate were first 
obtained by Gerrard. Kingzett gives the formula of pilocarpine 
as C23H34N404. The leaves also yield an essential oil, a terpene 
Cj0H16 (Hardy). Harnack and Mever state that the true formula 
for pilocarpine is CnII16N202, and that its effects resemble those of 
nicotine, but that it readily yields another alkaloid, jaborine, 
which probably closely approaches pilocarpine in composition, but 
is allied to atropine in effects, and may be contained, ready formed, 
in jaborandi. One salt is official (Pilocarpince Hydrochloras, 
CnHi6N202,HCl, U. S. P.). 
Piperine, or Pi peri a (Piper ina, U. S. P.) (C17TI19N03), is a feeble 
alkaloid occurring in white, black (Piper Nigrum, U. S. P.), long 
pepper (Chavica officinarum, Mign.) and cubeb pepper (Cubeba, 
U. S. P.), associated with volatile oil and resin ; to these three sub- 
stances the odor, flavor, and acridity belong. Piperine is obtained 
on boiling white pepper with alcohol, and evaporating the liquid 
with solution of potash, which retains resin. Recrystallized from 398 
THE ALKALOIDS. 
alcohol, piperine forms colorless prisms fusible at 212°. With acids 
and certain metallic compounds it forms salts, and distilled with 
strong alkali yields piperidine or piperidia (C5II10IIN), an alkaloid 
of strong chemical properties, and piperic acid (C12H10O4). Accord- 
ing to Buckheim, the amorphous resin of the peppers is similar in 
constitution to piperine, alkalies breaking it up into piperidine and 
chavicic acid. Pyrethrin is also said to he a member of the series. 
The piperine of eubeb pepper is not to be confounded with cubebin, a 
neutral constituent having the formula C33H34O 10- 
Sanguinarine, or Sanguinarina, is a colorless alkaloid obtained 
from the rhizome of Sangainaria canadensis (Sanguinaria, U. S. P.), 
or Blood-root. Its salts have a red, crimson, or scarlet color. It 
appears to be identical with Chelerythrin. 
Soi.anine, or Solania (C4:)H70NOlfi).—An alkaloid said to exist in 
the Woody Nightshade or Bitter-sweet (Solatium dulcamara). The 
dried young branches of the plant are official (Dulcamara, U. S. P.). 
It occurs also in the shoots, and jn minute amount in the skins of 
the tubers, of the potato (Solatium tuberosum). The alkaloid is only 
slightly soluble in water, alcohol, or ether; nitric acid colors it yel- 
low ; sulphuric acid produces at first a yellow, then a violet, and 
finally a brown coloration. It is said to be a conjugated compound 
of sugar with solanidine (C25II39NO). Geissler finds dulcamarin 
(C22II34OJ0), a glucoside, to be the bitter constituent of Solanum 
dulcamara. A mixture of sulphuric acid and alcohol, or either 
selenic acid or selenate of sodium and sulphuric acid, colors sola- 
nine or solanidine a dark red. 
Sparteine, or Sparteia (C15II26N), is a poisonous volatile alkaloid 
occurring in Broom-tops (Scoparius, U. S. P.). Its discoverer, Sten- 
house, considers that the diuretic principle of broom is scoparin, a non- 
poisonous body. Mills has obtained ethyl-sparteine (C13II25C„II5X) 
and diethyl-sparteine (C131I24C21I3C2II3N). 
Spigemna.—According to Dudley, this is a volatile alkaloid and 
active principle of Spigelia marilandica, or Pink-root (Spigelia, 
U. S. P.). 
Theine, Theia, or Caffeine (C8H10N4O2 + H20). This alkaloid 
(Caffeina, U. S. P.) occurs in tea, 1 to 4 per cent., coffee, .5 to 2 per 
cent., Mate or Paraguay tea, .2 to 2 per cent., guarana (Guarana, 
U. S. P., u a dried paste prepared from the crushed or ground seeds 
of Paullinia sorbilis ”), 5 per cent., and the kola-nut. Infusions 
and preparations of these vegetable products are used, chiefly as 
beverages, by three-fourths of the human race. It is remarkable 
that the instinct of man, even in his savage state, should have led 
him to select, as the bases of common beverages, just the four or 
five plants which out of many thousands are the only ones, so far as 
we know, containing theine. Theine is volatile. Considerable quan- 
tities may be collected by condensing the vapors evolved during the 
roasting of coffee on the large scale. The infusion of tea, from 
which astringent and coloring matters have been precipitated by 
solution of subacetate of lead, and which has been evaporated to a 
small bulk, yields a precipitate of theine on the addition of a strong VERATRINE. 
399 
solution of carbonate of potassium. It may be crystallized from 
alcohol or by sublimation. Theine forms salts with the stronger 
acids; they are decomposed by water. 
Test.—Concentrated nitric acid, or, better, a mixture of chlorate 
of potassium and hydrochloric acid, rapidly oxidizes theine, forming 
compounds which with ammonia yield a beautiful purple-red color, 
resembling the murexid obtained under similar circumstances from 
uric acid ; the oxidation must not be carried too far. Theine boiled 
with caustic potash yields methylamine (CH3HHN), the vapor of 
which has a peculiar characteristic odor. 
The chemical action of theine on the system is not yet made out. 
It is probably a pure stimulant. 
Veratrine, or Yeratria (Veratrina, U. S. P.) (CS2H50NO9, Schmidt 
and Koppen; C5.21I^;\20]3, Weigelin).—This alkaloid occurs in Ceca- 
(lilla (Sabadilla, B. P.; the seeds of Asagrea officinalis, Bindley, 
termed Sabadilla officinarium by Brandt, and Veratrum officinale by 
Schlecht). It is also said to occur in the leaves of Sarracenia pur- 
purea. According to Weigelin, Cevadilla contains two isomeric 
varieties of veratrine, the one soluble, the other insoluble, in. water. 
There are also present Sabadilline (C41IIfSN2013) and Sabatrine 
CjiIIggNjOjQ. The veratrine of trade contains the two latter alka- 
loids (Weigelin). A mere trace of veratrine brought into contact 
with the mucous membrane of the nose causes violent fits of sneez- 
ing. These alkaloids, and those from the different species of Vera- 
trum, are evidently very closely allied. Wright and Luff, by the 
use of tartaric acid, a solvent less likely than the strong acids to 
decompose alkaloids, extract from Cevadilla, Veratrine, C37II53XOn; 
Cevadine, C32H49N09; and Cevadilline, C3iIIMN08. 
The official process for the preparation of the alkaloid ( Ver atria, 
B. P .) consists in exhausting the disintegrated cevadilla-seeds by 
alcohol, recovering most of the spirit by distillation, pouring the 
residue into water, by which much resin is precipitated, filtering, 
and precipitating the veratrine from the aqueous solution by am- 
monia. It is purified by washing with water, solution in dilute hy- 
drochloric acid, decolorization of the liquid by animal charcoal, repre- 
cipitation by ammonia, washing, and drying. The U. S. P. (1870) 
process is similar, but includes treatment of the first crude veratrine 
by diluted sulphuric acid and precipitation of alkaloid by magnesia. 
Unguentum Veratrince, U. S. P., contains 4 per cent, of the alka- 
loid. 
QUESTIONS AND EXERCISES. 
694. IIow is Aconitine prepared? 
695. Give the strength of the official preparations of Atropine. 
696. Describe the properties of atropine. 
697. What is the active principle of stramonium? 
698. Mention pharmacopoeial substances containing beberine and 
berberine respectively. 
699. Give the characters of beberine. 400 
BITTER OR TONIC SUBSTANCES. 
700. In what does nectandrine differ from beberine? 
701. Mention the characteristics of coniine. 
702. What is the active principle of Ipecacuanha? 
703. Name the alkaloid of Tobacco. 
704. Give the name and properties of the active principle of Cala- 
bar Bean. 
705. What are the sources of piperine? 
706. Whence is theine obtained? 
707. Describe the preparations of veratrine. 
708. State the properties of veratrine. 
BITTER OR TONIC SUBSTANCES, Etc. 
The following articles, employed medicinally in such forms as 
Decoction, Extract, Infusion, Tincture, etc., contain active princi- 
ples which have not yet been thoroughly examined. Some of these 
principles have been isolated, and a few have been obtained in the 
crystalline condition, but their constitution has not been sufficiently 
well made out to admit of the classification of the bodies either 
among alkaloids, glucosides, acids, or other well-marked principles:— 
Andrographis Caides et Radix, 
P. I., from Andrographis pa- 
niculata, Kariyat. 
Anthemidis fores. 
Apocynum. Canadian Hemp. 
Asclepias tuberosa. Pleurisy-root 
(Asclepedin). 
Aurantii cortex (Hesperidin). 
Azadirachtce Cortex et Folia, P. 
I., from Azadirachta indica, 
Nim or Margosa. (A resin; 
C3fiU5«On- Broughton.) 
Baptisia tinctoria. Wild Indigo. 
Alkaloid? B. L. Smedley, 
Greene. 
Bonducella semina, P. I., from 
Ccesalpinia (guilandina) bon- 
ducella. Bondue-seeds or nick- 
ar-nuts. 
Buchu folia. 
Calendula officinalis. Marigold. 
(Calendulin, Stoltze.) 
Calotropis Cortex, P. I., from Ca- 
lotropisprocera and C.gigantea. 
Mudar. 
Canellce albce cortex. 
Cascarillce cortex (Cascarillin, 
C12IIn04). 
Caulophyllum thcdictroides. Blue 
cohosh. Alkaloid ? 
Cimicifuga (Actea) racemosa (Ci- 
micifugin?). Black snake-root. 
Cusparice cortex. Angustura-bark 
(Cusparin). 
Cypripedium pubescent* (Cypripe- 
din?). Ladies’ Slipper. 
Euonymus atropurpureus. Wa- 
hoo-bark (Euonymin ?). 
Eupatorium perfoliatum. Thor- 
oughwort or Boneset. 
Grindelia robusta. Resin? 
Gulancha (Tinosporce Radix et 
Guides, P. I.). 
Gynocardice semina, from Gyno- 
cardia odorata (Chaulniugra, 
Ilamamelis virginiea. Witch- 
hazel. 
Hedeoma pulegioides. American 
pennyroyal. 
Hydrocotyles folia, P. I., from 
Hydrocotyle asiatica. Indian 
pennywort. 
Iris versicolor. Blue flag (Iridin 
or Irisin?). 
Lactuca (Lactucin, etc.). The 
milk-juice, dried, yields Lactu- 
carium, U. S. P. 
Lappa, U. S. P., Arctium lappa, 
Lappa officinalis. Burdock. STARCH. 
401 
Lupulus. 
Magnolia. Swamp Sassafras or 
Beaver Tree. 
Marrubium. Horehound. Mar- 
rubein, a crystalline bitter 
substance (Mein). 
Maticce folia. Matico. 
Melia Azedarach (Resin, Jacobs). 
Fepo. The seed of Cucurbita 
pepo. A remedy for tape- 
worm. 
Phytolacca bacca et Radix. Poke, 
berry and root. Phytolaccin, 
a crystalline substance (Ciaas- 
sen). 
Quassias lignum (Quassin, 
cI0iiwo,). 
Scutellaria. Skullcap. 
Serpentaria. Virginia Snake-root. 
Stillingia. Queen’s Root. 
Soymidce Cortex, P. I. Rohun 
Bark, from Soymida fcbrifuga. 
Taraxaci radix (Taraxacin). 
Toddulice radix, P. I. 
Triticum repens. Rhizome of 
couch-grass. 
Veronica virginica, or Leptandra 
virginica. Culvers root; Lep- 
tandra, U. S. P. (Leptandrin?). 
Viburnum. Black haw. ( Vibur- 
nin). 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
STARCH. 
Formula C6II10O5; possibly C:2IT120O60. 
Processes.—Rasp or grate, or, with a knife, scrape, a portion 
of a clean raw potato, letting the pulp fall on to a piece of 
muslin placed over a small dish or test-glass, and then pour a 
slow stream of water over the pulp ; minute particles or gran- 
ules of starch pass through the muslin and sink to the bottom 
of the vessel, fibrous matter remaining on the sieve. This is 
potato-starch. Even diseased potatoes furnish good starch by 
this method. Wheat-starch (Amylum, U. S. P.) may be ob- 
tained by tying up some flour in a piece of calico and knead- 
ing the bag in a slow stream of water flowing from a tap, the 
washings running into a deep vessel, at the bottom of which 
the white starch collects; the sticky matter remaining in the 
bag is gluten. The Hue starch of the shops is artificially col- 
ored with smalt or indigo to neutralize the yellow tint of re- 
cently washed linen ; it should not be used for medicinal pur- 
poses. Starch dried in mass splits up into curious columnar 
masses, resembling the basaltic pillars of Fingal’s Cave in 
Staft'a or those of the Giant’s Causeway in the North of Ire- 
land. The cause of the phenomenon, which may also be seen 
in grain-tin, is not conclusively known. 
Gluten is the body which gives tenacity to dough and bread. It 
seems to be a mixture of vegetable fibrin, vegetable casein, and an 
albuminous matter termed glutin. These substances and gluten 
itself are closely allied ; each contains about 16 per cent, of nitrogen. 
Wkeaten Flour (Farina Tritici, E. P.) contains about 72 per cent, 
of starch and 11 of gluten, as well as sugar, gum, fine bran, water, 402 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
and ash. The compactness of barley, well seen in Husked or Pearl 
Barley (Hordeum Decortication, B. 1’.), is said to be due to the large 
amount of vegetable fibrin present. During germination the fibrin 
is destroyed; hence, probably, the cretaceous character of malt. 
Oatmeal is very rich in albumenoid or flesh-forming constituents, 
containing nearly 16 per cent. Sago is granulated starch from the 
Sago Palm. Tapioca is granulated starch from the Bitter Casava. 
The white translucent grains known as Bice are the husked seeds 
of Oryza sativa. Rice (Oryza) and the Flour of Rice, or Ground 
Rice (Oryza Farina), are official in the Pharmacopoeia of India. 
Rice is quite a staple article of food in tropical coutries. Ground 
rice reseriibles flour of wheat in composition, but contains from 85 
to 90 per cent, of starch. 
Microscopical Examination of Starches.—All kinds of starch 
afford the blue color with iodine, showing their chemical similarity. 
Physically, however, the granules of different starches differ from 
each other ; hence a careful microscopical examination of any starch, 
or of any powder or vegetable tissue containing starch, enables the 
observer to state, with a high degree of probability, the source of 
the starch, either at once if he has much experience, or after com- 
paring the granules in question with authentic specimens. A glance 
at the accompanying eight engravings* (Figs. 41 to 48) of common 
starches will show to what extent different starch-granules naturally 
differ in size, shape, general appearance, distinctness and character 
of the rugae, and position of the more or less central point or hilum. 
While from different starches individual granules may be picked out 
which much resemble each other, the appearance of each starch as a 
whole is fairly characteristic. That is to say, each group of granules 
differs in one, two, or several characters from similar groups of 
granules of other starches. 
A quarter-inch object-glass will commonly suffice for the micro- 
scopical examination of starch. A very little of the starch is mixed 
on a glass slide with a drop of water, a piece of thin covering-glass 
being placed on the drop and gently pressed, so as to provide a very 
thin layer for observation. Instead of water diluted spirit of wine, 
diluted glycerin, turpentine, or other essential oil, Canada balsam, 
and other fluids, may be used in cases where the markings or other 
appearances are not well defined. The illumination also of the 
granules may be varied, the light being reflected or transmitted, con- 
centrated or diffused, white or colored, polarized or plain. Polarized 
light is especially valuable in developing differences and in intensi- 
fying the effects of obscure markings. By polarized light the gran- 
ules of potato-starch appear as if traversed by a black cross ; wheat- 
starch granules and many others also peculiarly and characteristically 
influence polarized light. Distinctive characters will sometimes pre- 
sent themselves only when the granules are made to roll over in the 
fluid in which they have been temporarily mounted or when the 
* By permission of Messrs. Longmans & Co. these engravings have 
heen copied, with very few modifications, from the plates in two of the 
three volumes of the original edition of Pereira’s Materia Medica. STARCH. 
403 
STARCHES 
(Magnified 250 diameters). 
-950th of an ivrh.- 
Fi i/s. 41 to 4S. 
WHEAT /TR/TICUM, 
BARLEY (HORDEUM) 
I | • 
MAIZE (ZEA) 
( 
RICE (ORYZA) 
PEARL SAGO 
YjfEST INDIA ARROW BOOT MARAHTA) 
TAPIOCA (MANIHOT) 
P.OTAJO fsjolanum) 404 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
slide is gently warmed. Starches which have already been subjected 
to the inlluence of heat, partly as in sago or tapioca, or almost 
entirely as in bread, will of course differ in appearance from granules 
of the same starch before being dried, cooked, or torrefied. The 
characters of a starch will also somewhat vary according to the age 
and condition of the plant yielding it. 
For plates and descriptions of the characters of other starches 
occurring in plants used for medicinal purposes, the reader is re- 
ferred to works on Materia Medica and to the indexes of Journals 
of Pharmacy, as well as to general works and magazines on micro- 
scopy. For engravings of starch granules in situ, vide Berg’s Ana- 
tomischer Atlas, published by Gaertner, Berlin. 
The student may place fair confidence in the accompanying illus- 
trations and in most of the published engravings of starch granules; 
but in microscopical analyses of importance the worker should, if 
possible, himself obtain actual specimens of starches for comparison 
from the respective seeds, fruits, and other tissues. 
Initlin (C6 H10O5) is a white powder apparently occupying the 
place of starch in the roots of many plants, especially those of the 
natural order Compositce. Twenty to forty-five per cent, has been 
obtained from elecampane (Inula helenium). It is also contained 
in the dahlia, colchicum, arnica, dandelion, chicory, etc. It is 
soluble in boiling water, nearly all being redeposited on cooling. 
Iodine turns it yellow. Long ebullition converts it into a kind 
of gum. 
Lichenin (C6II10O5) is a white starch-like powder largely contained 
in many lichens—Iceland “ Moss,” Cetraria islandica, and many 
others. It is soluble in boiling water, and the fluid gelatinizes on 
cooling. It may be precipitated from its aqueous solution by alco- 
hol. With iodine it gives a reddish-blue color. 
Mucilage of Starch.—Mix two or three grains of starch with 
first a little and then more water, and heat to the boiling- 
point ; mucilage of starch (.Mucilago Amyli, B. P.) results. 1 
part of starch to 200 of water gives Gelatinized Starch, 
U. S. P. 
This mucilage or paste is not a true solution ; by long boiling, 
however, a portion of the starch becomes dissolved. In the latter 
case the starch probably becomes somewhat altered. 
Chemical Test.—To some of the mucilage add a little free 
iodine; a deep blue color is produced. 
This reaction is a very delicate test of the presence of either iodine 
or starch. The starch must be in the state of mucilage; hence in 
testing for starch the substance supposed to contain it must be first 
boiled in water. The solutions used in the reactions should also be 
cold or nearly so, as the blue color disappears on heating, though it 
is partially restored on cooling. The iodine reagent may be iodine- 
water or tincture of iodine. In testing for iodine its occurrence in 
the free state must be insured by the addition of a drop, or even DEXTRIN. 
405 
less, of chlorine-water. Excess of chlorine must be avoided, or chlo- 
ride of iodine will be formed, which does not color starch. 
The so-called Iodized Starch (Amylum Iodatum, U. S. P.), or iodide 
of starch (Starch, 95 ; Iodine, 5) scarcely merits the name of a chem- 
ical compound, the state of union of its constituents being feeble. 
Substances that attack free iodine remove that element from iodide 
of starch. The alkalies, hydrosulphuric acid, sulphurous acid, and 
other reducing reagents destroy the blue color. 
Composition of Starch Granules.—Starch granules consist mainly 
of gramdose, soluble in cold water and giving an indigo-color with 
iodine, and starch cellulose, insoluble in water and giving with 
iodine a dirty-yellow color. The starch cellulose forms an external 
coating upon the granule, and also exists mixed with the granulose 
inside the granule. If this coating be broken by mechanical 
means, the continued application of cold water will remove all the 
granulose, leaving the cellulose insoluble. By the action of diastase, 
ptyalin, and other ferments, and by other means, the granulose may 
be converted into sugar and dextrin, leaving the starch cellulose un- 
acted upon. 
Dextrin.—Mix a grain or two of starch with about half a 
test-tubeful of cold water and a drop or two of sulphuric acid, 
and boil the mixture for a few minutes ; no mucilage is formed, 
and the liquid, if sufficiently boiled, yields no blue color with 
iodine; the starch has become converted into dextrin and some 
sugar. Dextrin is also produced if starch is maintained at a 
temperature of about 320° F. for a short time. Dextrin is 
now largely manufactured in the latter way, and a paste of it 
used by calico-printers as a vehicle for colors ; it is termed 
British gum. The change may also be effected by diastase, a 
peculiar ferment existing in malt. Mix two equal quantities 
of starch with equal amounts of water, adding to one a little 
ground malt, then heat both slowly to the boiling-point; the 
mixture without malt thickens to a paste or pudding, that with 
malt remains thin, its starch having become converted into dex- 
trin and a sugar termed maltose. 
Diastase is probably a mixture of the coagulable albumenoids. 
It is so named from (haaraaig (diastasis), separation, in allusion to 
the separation, or rather alteration, it effects among the constituent 
atoms of the molecule of starch. This function is shared by the 
saliva, pancreatic juice, bile, and the intestinal and other juices. 
The function is destroyed when the albumenoids are coagulated by 
a temperature of from 80°-81° C. 
The Action of Diastase upon Starch.—Diastase has scarcely any 
action upon unbroken starch granules. The granules must be rup- 
tured by gelatinization with heat and moisture or in some other 
way. When a solution containing diastase, such as a cold-water 
infusion of malt, be allowed to act upon gelatinous starch or starch 
paste at GO0 to 70° C., liquefaction occurs. It is possible to operate 406 
AMYLACEOUS ANI) .SACCHARINE SUBSTANCES. 
so that when liquefaction has taken place the solution shall give no 
reaction for sugar or dextrin. If this solution be concentrated and 
allowed to cool, a glistening white precipitate of soluble starch 
falls. Soluble starch is probably the result of the partial decompo- 
sition of the more complex molecule of granulose or gelatinous 
starch. The next step in the action of diastase upon gelatinous 
starch is the breaking down of the soluble starch molecule into 
dextrin and a sugar called maltose. At least ten dextrins are suc- 
cessively produced, each simpler than the one preceding it, the pro- 
portion of maltose being correspondingly increased. The dextrins 
first produced give a red or brown color with iodine, while those last 
produced, and having a simpler molecule, give no color with iodine. 
The final reaction may be expressed thus:— 
10(Cj2H20O10) + 8II20 - 8(C12II22Ou) + 2(C12II20O10) 
Soluble starch. Maltose. Dextrin. 
The dextrins are distinguished by their rotary power, their reducing 
action on cupric salts, and in other ways. 
Starch heated with glycerin is converted into the soluble variety. 
The latter may be precipitated from an aqueous solution by strong 
alcohol. A strong solution in water gradually gelatinizes, owing to 
reconversion into insoluble starch (Zulkowsky). 
The Action of Dilute Acids upon Starch.—Dilute acids act upon 
gelatinous starch in the same way as diastase, except that the final 
product is glucose. 
Malt (the word malt is said to be derived from the Welsh mall, 
soft or “rotten”) is simply barley which has been softened by steep- 
ing in water, allowed to germinate slightly, and further change 
then arrested by the application of heat in a kiln. During germina- 
tion the gluten breaks up and yields a glutinous substance termed 
vegetable gelatin, diastase, and other matters. To the vegetable 
gelatin is due much of the “ body ” of well-malted and slightly- 
hopped beer; it is precipitated by tannic acid, hence the thinness of 
ale (pale or bitter) brewed witli a large proportion of hop or other 
materials containing tannic acid. A portion of the diastase, react- 
ing on the starch of the barley, converts it into dextrin, and, in- 
deed, carries conversion to the further stage of grape-sugar, as will 
be explained immediately. The temperature to which the malt is 
heated is made to vary, so that the sugar of the malt may or may 
not be partially altered to a dark-brown coloring-material; if the 
temperature is high, the malt is said to be high-dried, and is used 
in porter-brewing; if low, the product is of lighter color, and is 
used for ale (Maltum, U. S. P., “not darker than pale amber”). 
The diastase remaining in malt is still capable of converting a large 
quantity of starch into dextrin and sugar (maltose); hence the 
makers or distillers of the various spirits operate on a mixture of 
malted and unmalted grain in preparing liquors for fermenta- 
tion. 
Extract of malt is an evaporated infusion of malt. Taken with 
food, its diastase aids in the conversion of starch into a variety of 
sugar termed maltose and dextrin, and, pro tanto, assists enfeebled 
digestive powers. ISOMERISM. 
407 
3C#TI10O5 + II20 = C]2II22Ou + C5II]005 
Starch. Maltose. Dextrin. 
As diastase loses this power at a temperature above 150° F., that 
degree should not be exceeded in evaporating the infusion ; indeed, 
if the dissolved albumenoid matters are to be retained, the evapora- 
tion should be conducted at 120° F. (For a method of estimating 
the strength of extract of malt, see a paper by Dunstan and Dim- 
mock, Pharm. Journ., March 8, 1879.) 
Gam is a frequent constituent of vegetable juices, existing in large 
quantity in several species of acacia. According to Fremy, gum is 
a calcium salt, sometimes partially a potassium salt of the gummic or 
arabic radical. The formula of gummic acid is said to be H2C12- 
II,,0,0,11,0. Gum differs from dextrin in yielding mucic acid when 
oxidized by nitric acid. Cerasin, or cherry-tree gam, is an insoluble 
modification of acacia gum. Bassorin, traganthin or adraganthin 
(C12II20O10), is a form of gum which is insoluble in water, but absorbs 
a large quantity of that liquid and forms a gelatinoid mass. It 
occurs largely in Tragacanth, combined, like arabin, with calcium. 
Pectin, or vegetable jelly (C2.,II(0O.28,41I2O), is the body which gives 
to expressed vegetable juices the property of gelatinizing. It forms 
the chief portion of Irish or Carrageen “ Moss,” Chondrus crispus, 
(Chondrus, U. S. P.). Ceylon u Moss" (Gracillaria lichenoides and 
G. confervoides, P. I.) contains from one-third to three-fourths of 
vegetable jelly. 
The mucilage of marshmallow-root (Althea officinalis) (Althea, 
U. S. P.), and of linseed or common flaxseed (Linum usitatissimum), 
is a gum-like substance containing much mineral matter. It is the 
basis of the infusions termed mallow-tea and linseed-tea. Somewhat 
similar mucilage occurs in infusion of Bael; it is also largely yielded 
by the seeds of the Quince (Cydonium, U. S. P.) and by ordinary 
Elm-Bark ( Ulmi Cortex, B. P.), as well as by the bark of the Red or 
Slippery Elm (lilmi Fulvce) (Ulmns, U. S. P.). Salop, the powdered 
dried tubers of many species of Orchis, contains a large quantity of 
such matter. Squill also. The Indian Okra (Hibisci Capsalce, P. I., 
from Hibiscus esculentus) and Ispaghul- or Spogel-seeds (Ispaghulce 
semina, P. I., from Plantago ispaghula) also appear to contain a 
considerable quantity. In Sassafras-Pith (Sassafras Medulla, U. S. 
P.) starch and much mucilage occur. 
The composition of dextrin is represented by the same formula as 
that of starch, namely C6H10O5, for it has the same percentage com- 
position as starch. Inulin (p. 404) and cellulose have also a similar 
formula. There are many other bodies similar in centesimal com- 
position, hut dissimilar in properties; such substances are termed 
isomeric (iaog, isos, equal, and ylpog, meros, part), and their condition 
is spoken of as one of isomerism. There is sometimes good reason 
for doubling or otherwise multiplying the formula of one of two 
isomers, isomerides, or isomeric bodies. Thus a molecule of olefiant 
gas (ethylene), the chief illuminating constituent of coal-gas, is repre- 
Isomerism—Allotropy—Polymorphism. 408 
AMYLACEOUS AND SACCHARINE SUBSTANCES, 
sented by tho formula 021I4, while a molecule of amylene, an anaes- 
thetic liquid hydrocarbon, obtained from amylic alcohol, though 
having the same percentage composition as olefiant gas. is represented 
by the formula CDII10; for amylene, when gaseou.s, is about twice and 
a half as heavy fts ethylene, and must contain, therefore, in each 
molecule, twice and a half as many atoms, for (law of Avogadro) 
these equal volumes must contain equal numbers of molecules; its 
formula is, consequently, constructed to represent those proportions. 
(Read again pages 38-42.) This variety of isomerism is termed 
polymerism (from ttoIvq, pot us, many or much, and yepog, part). 
Metastannic acid (vide p. 239) is a polymeric variety or polymeride 
of stannic acid. An illustration of a second variety of isomerism is 
seen in the case of cyanate of ammonium and urea, bodies already 
alluded to in connection with Cyanic Acid. These and several other 
pairs of chemical substances have dissimilar properties, yet are simi- 
lar not only in elementary composition and in the centesimal propor- 
tion of the elements, but also in the fact that each molecule possesses 
the same number of atoms. But the reactions of these bodies indi- 
cate the probable nature of their construction; and this is shown in 
their formulae by the disposition of the symbols. Thus cyanate of 
ammonium is represented by the formula CNONH4, urea by COX.,II4. 
Such bodies are termed metameric (from yera, meta, a preposition 
denoting change, and yepoc), and their condition spoken of as one of 
metamerism. Acetate of ethyl (p. 297) is metameric with butyric 
acid (p. 360), for they have the same percentage composition and 
their vapors have the same specific gravity, and each therefore might 
be represented by the formula C41I802; but their properties warrant 
us in assuming that their atoms occupy different positions in the two 
molecules—-justify us in giving C,H5C2H302 as a picture of a mole- 
'cule of acetate of ethyl, and IIC4II702 as a picture of a molecule 
of butyric acid. Acetate of methyl (CH.C2H302), propionic acid 
(HC3I1502), and formate of ethyl (C2H5CH02) are isomers of the 
metameric variety, or metamerides ; also quinine and quinidine, cin- 
chonine and cinchonidine, and many of the volatile oils, etc. The 
isomerism of starch and dextrin may be of a polymeric or of a meta- 
meric character, but we do not yet know which, and must therefore 
at present give them identical formulae. Substances similar in com- 
position and constitution, yet differing in properties, are termed at lo- 
ir opic (dZZof, alios, another; rp6~or, tropos, condition). Thus ordi- 
nary phosphorus, kept at a temperature of about 450° F. in an 
atmosphere from which air is excluded, becomes red, opaque, insol- 
uble in liquids in which ordinary phosphorus is soluble, oxidizes 
extremely slowly, and only ignites when heated to near 500° F. (red 
or amorphous phosphorus). A black allotropic variety of phosphorus 
is known. There are also three allotropes of carbon, which are 
respectively crystalline, graphitic, and amorphous. Sulphur may be 
obtained in the viscous as well as in the hard, brittle condition. An- 
other illustration of allotropy is seen in the varieties of tartaric acid, 
which have different optical properties, but otherwise are identical; 
they are in neither of the above-mentioned states of isomerism, but 
are allotropic modifications of the same substance. Occasionally one CELLULIN. 
409 
and the same substance crystallizes in two distinct forms ; its state is 
then described as one of polymorphism [nolvs, polus, many •, yopfr), 
morphe, form). Sulphur is polymorphous. It-crystallizes by slow 
cooling in (1) prismatic crystals of sp. gr. 1.98, while in nature it 
occurs in (2) octahedra of sp. gr. 2.07. Melted and poured into 
water, sulphur takes up the form of (3) caoutchouc, of sp. gr. 1.96. 
These differences warrant the statement that sulphur occurs in three 
distinct allotropic conditions. Possibly such conditions result from 
the association of different numbers of atoms in the molecule of the 
element; that is, allotropic bodies may simply he physically polymeric 
or in some other way be mere physical isomerides. 
Cellulin, or cellulose, the woody fibre- of plants, familiar in the 
nearly pure state under the forms of “ cotton-wool ” ( Gossypium, B. P. 
and U. S. P., “hairs of the seed of various species of Gossypium”), 
paper, linen, and pith, is another substance isomeric, probably poly- 
meric, with starch. Lignin is a closely allied body lining the in- 
terior of woody cells, and vessels. By the action of nitric acid of 
various strengths on cellulin, peroxide of nitrogen (N02) is sub- 
stituted for one, two, or three atoms of hydrogen—mono-, di-, or tri- 
nitrocellulin being formed;— 
cyu10o5 + hno, = c6{ }o5 + h2o 
CtiII10O5 + 2IINO., = C6{ 2”«0 }o5 + 2H,0 
Cellulin. 
Nitric acid. 
V * “ 'L ) 
Mononitrocellulin. 
Water. 
Cellulin. 
Nitric acid. 
i. i > 
Dinitrocelluliu. 
Water. 
C6II10O5 + 3IINO, = Cc I }o5 + 3II20 
Trinitrocellulin is highly explosive gun-cotton ; dinitrocellulin is not 
sufficiently explosive for use instead of gunpowder; mononitrocel- 
lulin is scarcely at all explosive. The three movable atoms of 
hydrogen in cellulin may be displaced by bodies other than peroxide 
of nitrogen. 
Diftitrocellulin (Pyroxylinum, U. S. P.).—Mix 6 parts of 
sulphuric acid and 5 of nitric in an earthenware mortar. 
When cooled to about 32° C. (90° F.), immerse 1 part of 
cotton-wool in the mixture, and stir it with a glass rod so 
that it is thoroughly and uniformly wetted by the acids. 
Macerate for about ten hours, or until a sample washed with 
water and then with alcohol is soluble in a mixture of 1 vol. 
of alcohol and 3 of stronger ether. Transfer the cotton to a 
vessel containing a considerable volume of water, stir it rap- 
idly and well with a glass rod, decant the liquid, pour more 
water upon the mass, agitate again, and repeat the affusion, 
agitation, and decantation until the washing ceases to give a 
precipitate with chloride of barium or to taste acid. Drain the 
product on filtering-paper, and dry in a water-bath. 
Cellulin. 
Nitric acid. 
Tiiuitrocellulin. 
Water. 410 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
Pyroxylin may also be made by soaking 7 parts of white filtering- 
paper, which has been washed in hydrochloric acid and dried, in a 
mixture of 140 parts of suljdiurie acid (sp. gr. 1.82) and 70 of nitric 
acid (1.37) for three hours, and well washing the product (Guichard). 
Mononitrocellulin and trinitrocellulin are insoluble in a mixture 
of alcohol and ether; dinitroeellulin or pyroxylin is soluble, the 
solution forming ordinary collodion (Collodium, U. S. P.). The 
official proportions are 4 parts of pyroxylin dissolved in a mixture 
of 70 of stronger ether and 26 of alcohol. After digesting for a few 
days the liquid is decanted from any insoluble matter and preserved 
in a well-corked bottle. It is “ a colorless, highly inflammable liquid 
with ethereal odor, which dries rapidly upon exposure to the air, 
and leaves a thin, transparent film insoluble in water or rectified 
spirit.” Flexible collodion (Collodium Flexile, U. S. P.) is a mixture 
of collodion (92 parts), Canada turpentine, (5 parts), and castor oil 
(3 parts). A Styptic Collodion (Collodium Stypticum) is also official. 
709. How is wheat-starch or potato-starch isolated? 
710. Define gluten and glutin. 
711. Enumerate the proximate principles of wheaten Hour. 
712. Is starch soluble in water? 
713. Which is the best chemical test for starch? 
714. Distinguish physically between the varieties of starch. 
715. Into what compound is starch converted by heat? 
716. What occurs when a mixture of starch and water is allowed 
to flow into hot diluted sulphuric acid ? 
717. If equal amounts of starch and water be heated, one contain- 
ing a small quantity of ground malt, what effects ensue? 
718. Write a short article on the chemistry of “ malting.” 
719. What is the nature of gum-arabic, and how is it distinguished 
from “ British Gum ” ? 
720. Explain isomerism, giving several illustrations. 
721. Give examples of polymeric bodies. 
722. State the formula of a body metameric with urea. 
723. Define allotropy and polymorphism, giving illustrations. 
724. What form of cellulin is official? 
725. Mention the properties of the products of the action of nitric 
acids of various strengths on cellulin. 
726. How is pyroxylin prepared? 
QUESTIONS AND EXERCISES. 
Sucrose, or cane-sugar, C,2H22On. Maltose, C]2H22On- Laevu- 
lose, or inverted sugar, CfiH1206. Dextrose, glucose, or grape- 
sugar, CtiIIi20c,II.,0. Lactose, or milk-sugar, C12H.,2On,- 
h2o. 
Artificial Formation of Grape-sugar from Cane-sugar—Tests 
SUGARS SUGARS, 
411 
for Sugar.—Dissolve a grain or two of common cane-sugar in 
water. To a portion of* this solution placed in a test-tube add 
more water, two or three drops of solution of sulphate of 
copper, a considerable quantity of solution of potash or soda 
(enough to turn the color of the liquid from a light to a dark 
blue), and heat the mixture to the boiling-point; no obvious 
immediate change occurs. To another portion of the syrup 
add a drop of sulphuric acid, and boil for ten or twenty minutes, 
then add the copper solution and alkali, and heat as before; a 
yellowish-red precipitate of cuprous oxide (Cu20) falls. This 
test is exceedingly delicate. 
The above reaction is duo to the conversion of the cane-sugar 
(C12II22Ou) into inverted sugar, or Icevulose, C6lI12Ofi (so called because 
its solution causes left-handed rotation of a ray of polarized light, 
cane-sugar having an opposite effect), and grape-sugar, C6II1206,II20, 
by the influence of the sulphuric acid, and to the reducing action of 
the inverted sugar on the cupric solution. The formation of a pre- 
cipitate immediately, without the action of acid, shows the presence 
of the latter sugars—its formation only after ebullition with acid in- 
dicating, in the absence of starch or dextrin, cane-sugar. In this 
reduction process the sugar is oxidized and broken up into several 
substances, but the exact nature of the reaction has not been ascer- 
tained. 
Dextrin also reduces the copper salt to suboxide, unless its solu- 
tion is cold and very dilute. It does not, however, so act on a solution 
of cupric acetate acidified with acetic acid, while glucose produces 
with this liquid the usual red cuprous precipitate (Barfoed). 
Cane-sugar, or sucrose (Saccharum, U. S. is a frequent con- 
stituent of vegetable juices. Thus it forms the chief portion of 
cassia-pulp (Cassia Fistula, U. S. P.), is contained in the carrot and 
turnip, but is most plentiful in the sugar-cane; much, however, is 
now obtained from the sugar-maple and beet-root. On the evapora- 
tion of the juice common brown or moist sugar crystallizes out; this, 
by re-solution, filtration through animal charcoal, evaporation to a 
strong syrup, and crystallization in moulds, yields the compact 
crystalline conical loaves known in trade as loaf-sugar. From a 
slightly less strong syrup, slowly cooled, the crystals termed sugar 
candy are deposited, white or colored according to the color of the 
syrup. 
Maltose, C,2H22On.—This crystallizable sugar is formed, together 
with dextrin, when diastase or dilute acids act upon starch. In the 
case of diastase it is the ultimate product, but the dilute acids may 
convert it into dextrose. It reduces cupric salts, but to a less extent 
than dextrose. It differs also from dextrose in its optical activity. 
Inverted Sugar, or Lccvnlose, is uncrystallizable. It is found in the 
grape, fig (Ficus, U. S. P.) cherry, and gooseberry; both grape- 
sugar and fruit-sugar in the strawberry, peach, plum, etc. Fruit- 
sugar reduces cupric salts and ainmonio-nitrate of silver. 
Grape-sugar, glucose (from yAmvc, glue us, sweet), or dextrose, is 412 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
often seen in the crystallized state in dried grapes or raisins and 
other fruits; it is also the variety of sugar met with in diabetic urine. 
Its crystalline character is quite distinct from that of cane-sugar, the 
latter forming large four- or six-sided rhomboidal prisms, while 
grape-sugar occurs in masses of small cubes or square plates. Grape- 
sugar is also less soluble in water, but more soluble in alcohol, than 
cane-sugar. Grape-sugar reduces cupric salts and ammonio-nitrate 
of silver. 
According to Fresenius, the percentage proportion of saccharine 
matter in the dried fig is 60 to 70, grape 10 to 20, cherry 11, mul- 
berry 9, currant 6, whortleberry 6, strawberry 6, raspberry 4 (llubus 
Idceus, U. S. P ). 
Laevulose is loevogyrate, while sucrose and glucose possess right- 
handed rotation ; the latter twist a ray of polarized light from left 
to right to an extent dependent on the amount of sugar present—a 
fact easy of application in estimating the amount of sugar in syrups 
or in diabetic urine. 
Cane-sugar, maltose, and grape-sugar yield alcohol and carbonic 
acid gas by fermentation, the cane-sugar probably always passing 
into grape-sugar before the production of alcohol commences. 
Grape-sugar. 
C6TT1206 = 2C2HjHO + 2C0., 
Alcohol. 
Carbonic 
acid gas. 
In bread-making some of the starch is converted into dextrin, and 
this into sugar by the ferment. The above action then goes on, the 
liberation of gas producing the rising or swelling of the mixture of 
flour, water, and yeast (dough), the temperature to which the mass 
is subjected in the oven causing escape of most of the alcohol, and 
further expansion of the bubbles of carbonic acid gas in every part 
of the now spongy loaf. The carbonic acid gas gradually evolved 
when flour is worked up for bread with a mixture of dry bicarbonate 
of sodium and tartaric acid (best preserved by previous admixture 
with dried flour and a little carbonate of magnesium, baking-poicder) 
exerts similar influence. The least objectionable method of intro- 
ducing carbonic acid gas, however, is that of Danglish, whose patent 
aerated bread is made from flour by mere admixture with carbonic 
acid water under pressure. On removal from the cylinder the re- 
sulting dough expands by the natural elasticity of the imprisoned 
carbonic acid, and the bake-oven completes the process. The crumb 
of bread is official in Great Britain (Mica Panis, B. P.). 
Milk-sugar, or lactose (C12H24012) (Saccharum Lactis, U. S. P.), 
the sweet principle of the milk of various animals, is not susceptible 
of alcoholic or vinous fermentation, but it resembles grape-sugar in 
reducing an alkaline solution of copper with precipitation of subox- 
ide. It is readily obtained from milk by adding a few drops of acid, 
stirring, setting aside for the curds to separate, filtering, evaporating 
the wheg to a small bulk, filtering again if necessary, and allowing 
to cool and crystallize. It usually occurs in trade “ in cylindrical 
masses two inches in diameter, with a cord or stick in the axis, or 
in fragments of cakes—grayish-white, crystalline on the surface and 
in its texture, translucent, hard, scentless, faintly sweet, gritty when SUGARS. 
413 
chewed.” It is soluble in 6 parts of cold and 3 of boiling water; 
slightly soluble in alcohol; insoluble in ether. Powdered milk- 
sugar is used in pharmacy as a vehicle for potent solid medicines. 
Milk-sugar is convertible, by the action of dilute acids, into “galac- 
tose” and “ lactoglucosethese may be reunited to form milk-sugar. 
“ Milk-sugar, when sprinkled upon 5 parts of sulphuric acid, should 
acquire not more than a greenish or reddish, but no brown or black- 
ish-brown, color within one hour (abs. of cane-sugar).1'—U. S. P. 
Action of Alkali on Sugar.—To a little solution of grape- 
sugar add solution of potash or soda, or solution of carbonate 
of potassium, and warm the mixture; the liquid is darkened 
in color from amber to brown, according to the amount of 
sugar present. 
Tests.—The copper reaction, the fermentation process, and the 
effect of alkalies form three good tests of the presence of grape- 
sugar, and, indirectly, of cane-sugar. A piece of merino or other 
woollen material, previously dipped in a solution of stannic chloride 
and dried, becomes of a brown or black color when dipped in a solu- 
tion of glucose and heated to about 300° F. by holding before a fire. 
Sugar from Starch.—Boil the starch with a little water and 
a drop of sulphuric acid as for dextrin, but continue the ebulli- 
tion for several minutes ; on testing a portion of the cooled 
liquid with iodine and another portion with the heated alkaline 
solution of a copper salt as described on page 411, it will be 
found that the starch has nearly all become converted into a 
sugar—dextrose. Maltose is also formed, at first, but by the 
continued action of the acid is changed to dextrose. When 
made on a large scale, a warm (131° F.) mixture of starch 
and wrater of the consistence of cream is slowly poured into a 
boiling solution of one part of sulphuric acid in one hundred of 
water, the whole boiled for some time, the acid neutralized by 
chalk, the mixture filtered, the liquid evaporated to a thick 
syrup and set aside; in a few days it crystallizes to a granular 
mass resembling honey. In this operation a small quantity of 
dextrin remains with the glucose, but if the process be con- 
ducted under pressure, conversion, according to Manbre, is 
complete. Sugar made from the starch of rice, maize, etc. is 
now largely used for table syrups, confectioneries, bee-food, 
and as a partial substitute for malt in brewing. It is known 
asputent sugar, saccharine, dextrin-maltose, etc. In the United 
States dealers commonly term the thick syrup glucose, and the 
further evaporated, solid product grape-sugar. 
The sugar in fresh fruits is mainly cane-sugar, but by the action 
of the acid, or possibly of a ferment in the juice, it is gradually con- 
verted into inverted sugar, a variety differing from cane-sugar in 414 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
being uncrystallizable, and in having an inverted or opposite influ- 
ence on polarized light, twisting the ray from right to left (laevo- 
gyrate, having laevo-rotation, hence sometimes termed Icevulose). 
Ripe Hips (ltosce Canince Fructus, B. P.) contain 30 per cent, of 
such sugar, besides gum and acid malates and citrates. Fruit-sugar, 
as gathered in the form of syrup by bees, is probably a mixture of 
these two varieties. It is gradually altered to a crystalline or gran- 
ular mass of grape-sugar, as seen in dried fruits, such as Raisins 
( Uvce, B. P ) and the Prune (Prunnm, U. S. P.), and in solidified honey 
(Mel, B. P. and U. S. P.). This, the common form of grape-sugar, is 
dextrogyrate, and hence is sometimes termed dextrose, to distinguish 
it from laevulose. Diluted with twice its weight of water, it yields 
a liquid having a sp. gr. 1.101 to 1.115. “If 1 part of honey be 
dissolved in 4 parts of water, a clear solution should result, which 
should not be rendered more than faintly opalescent by a few drops 
of test-solution of nitrate of silver (chloride) or of nitrate of barium 
(sulphate). If a small portion of honey be diluted with 1 volume of 
water and then gradually mixed with 5 volumes of absolute alcohol, 
it should not become more than faintly opalescent, and should neither 
become opaque nor deposit a slimy substance at the bottom and along 
the sides of the test-tube. When incinerated in small portions at a 
time in a platinum crucible, it should not leave more than 0.2 per 
cent, of ash (any larger percentage of ash and failure to respond to 
the preceding tests indicating the presence of glucose or other for- 
eign admixtures). Water boiled with honey, and allowed to cool, 
should not be rendered blue or green on the addition of test-solution 
of iodine (abs. of starch) ”—U. S. P. Honey often contains pollen, 
hairs, spores, the dust and dirt from the flowers, and various floccu- 
lent matters which cause it to ferment and yield inannite (Stcddart), 
alcohol, and acetic-acid; hence for use in medicine it (Mel Despuma- 
tum, U. S. P.) should be clarified by melting and straining, while hot, 
through flannel previously moistened with warm water. A mixture 
of clarified honey 80 per cent., acetic acid 10 per cent., and water 10 
per cent, is official under the name of Oxymel (from ofiV, oxus, acid, 
and yDu, honey). A similar mixture of honey with acetic acid con- 
taining the soluble portions of squill-bulbs (SeilJa, U. S. P.) is known 
as Oxymel of Squill (Oxymel Scillee, B. P.). Honey or sugar-cane 
are the bases of the official Confections. 
“ Honey Dew" is a viscid saccharine matter occasionally met with 
on the leaves of the lime, maple, black alder, rose, and other trees. 
Sometimes it is sufficiently abundant to dry and fall on the ground, 
forming a veritable “shower of manna.” It is a mixture of cane- 
sugar, inverted sugar, and dextrin. 
Barley-sugar is made by simply heating cane-sugar till it fuses, a 
change from the crystalline to the uncrystallizable condition occur- 
ring. Treacle (Theriaca, B. P.), Molasses, or Melasses (from Mel, 
honey), chiefly results from the application of too much heat in 
evaporating the syrups of the sugar-cane; it is a mixture of cane- 
sugar with uncrystallizable sugar and coloring-matter. Liquorice- 
root (Glycyrrhizce Radix, B. P.) contains a considerable quantity of 
uncrystallizable sugar. SUGARS. 
415 
Caramel.—Carefully heat a grain or two of sugar in a test- 
tube until it blackens; the product is caramel or burnt sugar 
(the Saccharum Ustum of pharmacy). It is used as a coloring 
agent for gravies, confectioneries, spirits, and similar materials. 
Mannite (C6II1406).—Boil manna with alcohol, filter, and 
set aside; mannite separates in colorless shining crystals or 
acicular masses to the extent of from bO to 80 per cent, of 
the manna. 
Manna, U. S. P., is a concrete saccharine exudation from the stem 
of Fraxinus ornus and F. rotund [folia; it is obtained by making 
incisions in the stem of the trees. It occurs in “ stalactiform pieces 
from one to six inches in length and one or two inches in width, 
uneven, porous and friable, curved on one side, of a yellowish-white 
color, with a faintly nauseous odor and a sweetish taste.” Sp. gr. 
0.834. Mannite is also met with in celery, onions, asparagus, cer- 
tain fungi, and sea-weeds, occurs in the exudations of apple and pear 
trees, and is produced during the vinous fermentation of sugar. 
Mannite is an alcohol, the radical of which is sexivalent (C61I8)VI- 
6IIO (Wanklyn). It is closely related to the sugars, glucose becom- 
ing mannite by action of nascent hydrogen :— 
C.HltO. + II2 = CJI.A, 
Glucose. Hydrogen. Mannite. 
Indeed, glucose itself is probably an alcohol of another radical 
(CfilIfi)v,6H0. Mannite does not undergo vinous fermentation in 
contact with yeast. It is soluble in 5 times its weight of cold 
water. 
Mucic Acid (II2C6H808) and Saccharic Acid (H2C6TI808) are two 
isomeric bodies formed by the action of dilute nitric acid on certain 
sugars, gum, mannite, etc. 
QUESTIONS AND EXERCISES. 
727. IIow are cane-sugar and grape-sugar analytically distin- 
guished ? 
728. Describe the methods of extracting and purifying cane-sugar. 
729. Mention the chief sources of cane-sugar. 
730. Give chemical explanations of the different processes of 
bread-making. 
731. IIow is milk-sugar obtained, and in what respects does it 
differ from other sugar? 
732. By what process may starch be entirely converted into sugar? 
733. What is the difference between fruit-sugar and honey? 
734. What is Oxymel ? 
735. Describe tfie effect of heat on cane-sugar. 
736. Describe the source and character of manna. 
737. Give the latest view of the constitution of mannite. 
738. Whence are mucic and saccharic acids obtained? 416 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
THE GLUCOSIDES. 
Source.—The glucosides are certain proximate vegetable principles 
which, by ebullition with dilute acid or other method of decomposi- 
tion, take up the elements of water and yield glucose, accompanied 
by a second substance, which differs in each case according to the 
body operated on. Several of the glucosides which are of pharma- 
ceutical interest will now be considered. Tannin, or tannic acid, 
is also a glucoside; it has been described among the acids. 
There are indications that glucosides may he regenerated from the 
bodies into which they are converted by heat. 
Note on Nomenclature.—The first syllable of the names of gluco- 
sides and neutral principles generally is commonly given in allusion 
to origin ; the last syllable is in, which sufficiently distinguishes 
them as a class. 
Amygdalin (C20H27NOm,3H2O).—This body, obtained by 
Robiquet and Boutron-Charlard in 1830, was the first dis- 
covered glucoside (Liebig and Wohler, 1837). It is a white 
crystalline substance existing in the bitter (.Amygdala Amara, 
U. S. P.) but not in the sweet almond (Amygdala Balds, 
U. S. P.). About 2 per cent, is readily extracted by strong alco- 
hol from the cake left when the fixed oil has been expressed 
from bitter almonds. From the concentrated alcoholic solution 
ether precipitates the amgydalin. 
Make an emulsion of two or three sweet almonds by bruising 
and rubbing them with water, and notice that it has no odor of 
essential oil of bitter almonds : add a grain or two of amyg- 
dalin, an odor' of essential oil of bitter almonds is at once de- 
veloped. Bruise two or three bitter almonds and rub with 
water; the volatile oil is again developed (Oleum Amygdalae, 
Amarse, U. S. P.). Sp. gr. 1.060 to 1.070. 
Bitter Almond-water (Aqua Amygdalae Amarse, TJ. S. P.) is 
made by filtering a mixture of 1 part of the oil with 999 parts 
of distilled water. 
The source of the hydride of benzoyl, or essential oil of bitter 
almonds, in these reactions is the amygdalin, which, under the 
influence of synaptase or emulsin, a nitrogenous casein-like ferment 
existing in both bitter and sweet almonds, splits up into the essential 
oil, hydrocyanic acid, and glucose :— 
Amygdalin. 
C20H27NOu + 2H20 = C7H,OII + IICN + 2CfiII1206 
Water. 
Hydride of 
benzoyl. 
Hydrocy- 
anic acid. 
Glucose. 
As each molecule of amygdalin yields one of hydrocyanic acid, a 
simple calculation shows that 17 grains (mixed with emulsion of 
sweet almonds) will be required to form one grain of real hydro- 
cyanic acid, a quantity equivalent to 50 minims of the dilute hydro- 
cyanic acid of the British Pharmacopoeia. The hydrocyanic acid is 
probably in chemical combination with the oil. 
Test.—The reaction between synaptase and amygdalin is applica- THE GEUCO,SIDES. 
417 
ble as a test of the presence of one by the addition of the other, even 
when mixed with much organic matter. 
Jacobsen obtains benzaldehyd from benzodichloride (dichloro- 
methylbenzol, C6II5CIIC12), one of the dichlorotoluenes, by heating 
with glacial acetic acid, chloride of zinc, and a little water. 
Cherry-Laurel Water (Aqua Laurocerasi, B. P., by distillation 
with water from Laurocerasi Folia, B. P.) contains hydrocyanic 
acid derived from a reaction similar to, indeed probably identical 
with, that just described, for bitter-almond oil is simultaneously 
produced. But the proportion of amygdalin or analogous body in 
cherry-laurel leaves is most variable; hence the strength of the 
water is highly uncertain. It should contain perhaps two to four 
parts of hydrocyanic acid in ten thousand. 
Prunus Virginiana, U. S. P., the bark of Primus serotina or 
Cerasus serotina, the W ild Black Cherry Bark, also furnishes by 
distillation an essential oil and hydrocyanic acid ; quince-seeds also 
( Cydonia vulgaris). The Wild Black Cherry contains amygdalin. 
Caution.—Essential oil of almonds is of course highly poisonous. 
The purified oil or hydrate of benzoyl is almost innocuous; it is 
obtained on distilling the crude oil with milk of lime and ferrous 
chloride, and thoroughly drying the product by shaking with fused 
chloride of calcium. Sp. gr. 1.043 to 1.049. The so-called “ arti- 
ficial oil of bitter almonds ” or nitrobenzol (C6II5(N02)), when taken 
in quantity, has been known to produce death. The presence of 
nitrobenzol in oil of bitter almonds is detected by adding a little of 
the oil to a mixture of zinc and diluted sulphuric acid, shaking well, 
setting aside for an hour or two, filtering off' the clear liquid, and 
adding a little chlorate of potassium ; a violet color (actual mauve) 
is produced. Or the specimen may be shaken with bisulphide of 
sodium to fix the essential oil, and then with ether, which dissolves 
out, and on evaporation will yield the nitrobenzol. 
Arbutin (C24H.t2014,II20) is contained in leaves of Arctostaphylos 
uva-ursi and Chimaphila umbellata (Chimaphila, U. S. P., or Pip- 
sissewa). It is a bitter neutral body occurring in acicular crystals, 
and resolvable by acids into hydroquinone (C6il602) and glucose, and 
by gentle oxidation into quinone (CeH402) and formic acid. Ericolin 
(C34II56021) is another bitter glucoside in bearberry leaves. 
Brvoxin (C48IIto019, Walz).—The colorless, bitter, indistinctly 
crystalline principle of Bryony (Bryonia, U. S. P., the root of Bry- 
onia alba and Bryonia dioica). 
Cathartic Acid.—u The glucoside acid that now is known to 
confer on the Senna of Alexandria (from Cassia acutifolia) and of 
India (from Cassia elcmgata) {Senna, U. S. P.) its purgative prop- 
erty has been named by its discoverers (Dragendorff and Kubly) 
carthartic acid. Its formula has been stated as C180H192N4S082, 
which, if true, accounts for its extreme stability. It is insoluble 
in water, strong alcohol, and ether, but enters readily into watery 
solution when combined with alkaline and earthy bases, in which 
state it exists in senna. Its ammonium salts give brownish floccu- 
lent precipitates with salts of silver, tin, mercury, copper, and lead. 418 
AMYLACEOUS ANT) SACCHARINE SUBSTANCES. 
Antimonial salts, tannin, yellow and red prussiates have no effect 
upon it. Alkalies, aided by heat, act destructively upon it. Boiled 
with a mineral acid, it splits into a peculiar kind of glucose and an 
acid that has been named Cathartogenic; its formula is said to be 
C]32II116N4S044. The natural cathartate occurring in senna is pre- 
pared by partially precipitating by strong spirit a water infusion of 
senna, concentrated to a syrupy state by evaporation in vacuo. The 
filtrate is now treated with a much larger bulk of absolute alcohol, 
and the precipitate thus obtained is purified by repeated solution in 
water and precipitation by alcohol. To obtain the pure acid, ad- 
vantage is taken of its colloidal properties; the crude cathartate is 
dissolved in moderately strong hydrochloric acid, and subjected to 
dialysis on a diaphragm of parchment-paper. The minimum dose 
of this pure acid was found to be about \\ grains, which caused 
several stools with decided griping. 
“ The cathartic combinations that I have made are the cathartate 
of ammonium, prepared from cathartate of lead by my original pro- 
cess, and the mixed cathartates, prepared according to Dragendorff s 
method as modified by myself. Of the former nearly pure salt I 
have found 3f grains to purge fairly as to amount, but slowly as 
to time, and with considerable griping. Of the latter, 7£ grains 
purged violently with much griping and sickness, which continued 
through the greater part of the day. It obviously would be im- 
proper to combine senna with any of its metallic precipitants, should 
such be desired, which is not likely. It is here satisfactory to observe 
that the cathartate of magnesium is soluble, and that the old-fash- 
ioned black draught agrees with new-fashioned science ” (Groves). 
Buckthorn-juice (Rhanmi Succus, B. P.) owes its cathartic prop- 
erties to a substance apparently identical with cathartic acid. Pos- 
sibly the purgative properties of the bark of the Rhamnus frangula 
(Frangula, U. S. P.), Black alder, Buckthorn, also, are due to ca- 
thartic acid. 
Colocvnthin (C^II^O.,.,?).—This substance is the active bitter 
and purgative principle of colocynth-fruit (Colocynihis, U. S. P.); 
it is soluble in water and alcohol, but not in ether. By ebullition 
with acids it furnishes glucose and a resinoid body. 
Convolvulin. See -Jalapin. 
Cotoin (C22H1806) appears to be the chief active principle of 
Coto-bark, a Bolivian remedy for diarrhoea. 
Daphnin (C31H340I9) is the crystalline glucoside of the bark 
of Daphne mezereum (Mezerei Cortex, B. P.). Boiled with di- 
lute acids, it yields daphnetin (Cl9IIu09) and glucose. The 
acrid principle of mezereon is resinoid. 
Digitalin (C27Hi5015, Kosman; C5H802, Schmiedeberg).— 
This is an active principle of the Foxglove ( Digitalis, U. S. P.). 
Boil a grain of digitalin (Digitalinnm, B. P.) with sulphuric 
acid for some time; flocks of digitaliretin (C15H2305) separate, 
and glucose may be detected in the liquid. THE GLUCOSIDES. 
419 
C27H45015 + 2H20 = C15H2505 + 2C6H,A 
Digitalin. Water. Digitaliretin. Glucose. 
Properties.—Digitalin occurs 11 in porous mammillated masses or 
small scales, white, inodorous, and intensely bitter, readily soluble 
in spirit, but almost insoluble in water and in pure ether, dissolves 
in acids, but does not form with them neutral compounds; its solu- 
tion in hydrochloric acid is of a faint-yellow color, but rapidly be- 
comes green. It leaves no residue when burned with free access of 
air. It powerfully irritates the nostrils, and is an active poison.” 
According to Pettenkofer, an intense red color is produced if a trace- 
of digitalin dissolved in water is mixed with a weak aqueous solu- 
tion of inspissated bile, and sufficient oil of vitriol added to raise 
the temperature to 158° F. Moistened with sulphuric acid and 
the liquid exposed to the vapor of bromine, a violet color is pro- 
duced. 
Process.—The process for the preparation of digitalin consists in 
dissolving the glucoside out of the digitalis-leaf by alcohol, remov- 
ing the alcohol by distillation, dissolving the residue in water by 
the help of a small quantity of acetic acid, removing much of the 
color from the solution by animal charcoal, neutralizing most of the 
acetic acid by ammonia, precipitating the digitalin by tannic acid 
(with which it forms an insoluble compound), washing the pre- 
cipitate, rubbing and heating it with spirit and oxide of lead 
(which removes the acid in the form of insoluble tannate of lead), 
again decolorizing by animal charcoal, evaporating to dryness, wash- 
ing out impurities still remaining by ether, and drying the residual 
digitalin. In this form digitalin is uncrystallizable. 
Pure Digitalin (/)—On treating commercial digitalin with chlo- 
roform only an inert substance remains undissolved. The solution 
yields pure digitalin on evaporation ; it may be crystallized from 
spirit in radiating needles (Nativelle). The therapeutic effect of 
the pure substance is identical with the preparations of digitalis, 
but, as might be expected, more constant in its action, and of 
course intensely powerful. Digitoxin (C311I3307) is a highly poi- 
sonous substance extracted from Foxglove by Schmeideberg. The 
same chemist regards commercial digitalin from Foxglove-seeds 
as composed of three glucosides—namely, pure Digitalin (C5H802), 
Digitonin (C31II32017), closely allied to saponin, and Digitalein. 
Elaterin (C26H,s05).—Boil elaterium, the dried sediment 
from the juice of the squirting cucumber-fruit (Ecballium 
Elaterium), in a small quantity of spirit of wine, and filter; 
fibrous and amylaceous matters remain insoluble, while elaterin 
and resin are dissolved. The filtrate, concentrated and poured 
into a warm solution of potash, yields, on cooling, crystals of 
elaterin, resin being retained by the alkali * It is purified by 
* “ The alcoholic solution should not he precipitated bv tannic acid 
nor by salts of mercury or of platinum (abs. of, and difference from, 
alkaloids).” 420 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
recrystallization from spirit (Elaterin, U. S. P.). Boil elaterium 
in dilute sulphuric acid for an hour or two, filter, and test the 
clear liquid for glucose; a reddish precipitate of cuprous oxide 
falls. This reaction is readily obtained with elaterium, but not 
always with elaterin ; hence probably the latter is not a true 
glucoside. Walz states that elaterium also contains prophetin, 
a true glucoside.' 
Elaterin is the active principle of the so-called elaterium. Elate- 
rium occurs u in light, friable, slightly-incurved cakes, about one 
line (T\ inch) thick, greenish-gray, acrid and bitter; fracture finely 
granular.” Good specimens of this drug should yield, according to 
the British Pharmacopoeia, not less than 20 per cent, of elaterin by 
the above process. Elaterium adulterated with chalk and other 
substances was formerly occasionally met with. A Trituration of 
Elaterin is official (Trituratio Elaterini). It is a mixture of 1 part 
of elaterin with 9 of sugar of milk. 
According to the experience of Fliickiger and Hanbury, the 
best method of obtaining elaterin is to exhaust elaterium with 
chloroform, and then to add ether to the chloroform, when crys- 
talline elaterin is precipitated. It should be washed with a 
little ether and crystallized from chloroform. When pure it 
occurs in hexagonal scales or prisms. 
Test.—A little is placed in a watch-glass with a drop or two 
of liquefied carbolic acid, and then two or three drops of strong 
sulphuric acid; a carmine color is developed (Lindo). 
Gentiopicrin, or Gentian-bitter (C20H30Oi2), the neutral 
crystalline principle of the root of Gentiana lutea (Radix Gni- 
tiause, B. P.). It is soluble in water and weak spirit. Alkalies 
decompose it. Dilute acids convert it into gentvtgenin and glu- 
cose. Gentian-root also .contains a variety of tannin and a 
crystalline acid (IIC)4II905) termed gentianic or gentium acid or 
gentisin. Fused potash, etc. gives with the latter an acid 
(C7II604) which has also unfortunately been called gentisic 
acid. 
Glycyrriiizin (C24H3609, Gorup-Besanez). — Liquorice- 
root ( GlyryrrhizaU. S. P.) in addition to uncrystallizable sugar 
contains a sweet substance, glycyrrhizin, which, when boiled 
with hydrochloric acid or dilute sulphuric acid, yields a resi- 
noid bitter body, glycyrrhetin. and an uncrystallizable sugar re- 
sembling glucose. Glycyrrhizin is only slightly soluble in 
cold water, but is taken up by diluted alcohol containing a lit- 
tle ammonia (Extractum Glycyrrhizse Fluid-urn, U. S. P.) or by 
ammoniacal water. An infusion in the latter, evaporated to a 
pilular consistence, forms Extractum Glycyrrhizse Purum, IT. S. THE GLUCOSIDES. 
421 
P. It is present in considerable quantity in the evaporated 
decoction (aStick Liquorice, Spanish Liquorice, or Solazzi Juice). 
The tropical substitute for liquorice is the root of Ahrus pre- 
catorius, or Indian Liquorice (Ahri Radix, P. I.), which also 
apparently contains glucose and glycyrrhizin. Glycyrrhizin has 
considerable power of disguising nauseous flavors. Poussin 
refers the sweet taste of liquorice not to pure glycyrrhizin, but 
to a combination of glycyrrhizin with alkalies, and states that 
ammoniacal glycyrrhizin has exactly the sweetness of liquoiice- 
root. The formula of this qlycyrrhizate of ammonium is said 
by Habermann to be (NH4)3C44H60NO18. Sestini finds that the 
glycyrrhizin of liquorice-root is chiefly glycyrrhizate of lime. 
An Ammoniated Glycyrrhizin (Giycyrrhizinum Ammoniatum, 
U. S. P.) is directed to be prepared by precipitating a dilute 
ammoniacal percolate with sulphuric acid, washing, redissolv- 
ing in ammoniacal water, reprecipitating, again washing, dis- 
solving in solution of ammonia, and spreading on glass plates 
to dry until reddish-brown scales are obtained. 
GrUAlAClN.—Pesin of guaiaeum (Guaiaci Resina, U. S. P.), 
an exudation from the wood (Guaiaci Lignum, U. S. P.) of 
Guaiaeum officinale, is probably a mixture of several sub- 
stances, among which are Guaiaretic, or Guaiaretinic acid 
(0*11*04) (Hlasiwetz), Gnaiaconic acid (C38H40O10) (Iladelich), 
and Guaiacin, a glucoside. On boiling guaiaeum resin with 
dilute sulphuric acid for some time, glucose is found in the 
liquid, a green resinous substance (guaiaretin) remaining in- 
soluble (Kosmann). Most oxidizing agents, and even atmo- 
spheric air, especially under the influence of certain organic 
substances, produce a blue, then green, and finally a brown 
color, when brought into contact with an alcoholic solution of 
guaiaeum resin. 
These effects are said to be due to three stages of oxidation 
(Jonas). They may be observed on adding the solution to the 
inner surface of a paring of a raw potato. 
Helleborin (C3BH4206) and Helleborein (C2BH440,5) are 
crystalline glucosides occurring in the roots of Black Hellebore 
(lle/lehorus niger), or Christmas Pose, and Green Hellebore 
(//. viridis), ranunculaceous herbs. 
Jalapin (QnHsoOi,,) and Convolvulin (C34II56016).—Ac- 
cording to Keyser and Meyer, jalap resin contains two distinct 
substances—convolvulin, chiefly obtained from Mexican male 
jalap (.Ipomcea orizabensis), and jalapin, most largely contained 
in the true jalap (.Ipomcea purga) ; the former is soluble in 
ether, the latter insoluble. Boil jalap resin with dilute sul- 422 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
phuric acid for some time, and filter; a substance, which is 
probably a mixture of jalapinol (C1:jH2A) and convolvuli nol 
(C1bHs(A), separates, and glucose may be detected in the clear 
liquid. (It is to be regretted that the authors transpose the 
above names, terming the old well-known jalapin convolvulin.) 
CnHaoO,, + 5H20 - C13H2A + 3C6H,A 
Jalapin. Water. Jalapinol. Glucose. 
Jala pic Acid.—This is contained in the portion of jalap 
resin soluble in ether. It may also be obtained from jalapin 
by ebullition with alkalies :— 
2C31H5nOI6 + 3H,0 = C6*H106O35 
Jalapin. Water. Jalapic acid. 
Jalap resin (Resina Jafapse, U. S. P.) is obtained by digest- 
ing and percolating jalap tubercles (Jalapa, U. S. P.) with spirit 
of wine, distilling oft’ most of the spirit, pouring into water, 
decanting the aqueous portion, which contains much saccharine 
matter, and washing and drying the residual resin. The tinc- 
ture is sometimes decolorized by animal charcoal, and the 
evaporated product sold as “jalapin.” 
Jalap resin is insoluble in oil of turpentine; common resin or 
rosin, soluble. If the presence of the latter is suspected, the speci- 
men should be powdered, digested in turpentine, the mixture filtered, 
and the filtrate evaporated; no residue, or not more than yielded by 
the turpentine itself, should be obtained. 
Tampico Jalap, from Ipomoca simulans, yields a resin, which ap- 
parently is chiefly convolvulin, but sometimes contains jalapin ; for 
a sample obtained by Hanbury was entirely soluble in ether, and 
another extracted byUmney was almost wholly soluble, while Evans 
purified some, half only of which was soluble. 
The Kaladana resin or Pharbitisin of India (from Pharbitis 
Nil, P. I.) is a cathartic analogous to, if not identical with, resin of 
jalap. 
Picrotoxin (U. S. P.) is a crystalline bitter poisonous principle 
(ttucpbc, picros, bitter, and toxicon, poison) occurring in Coc- 
culus indicus, the dried fruits of Anamirta cocculus (Anamirta pan- 
iculata, Colebrooke). Ludwig regarded it as a glucoside. Barth 
and Kretschy state that the so-called picrotoxin may be separated 
into picrotoxin proper (C15II]S0.1I20), which is bitter and poisonous; 
picrotin (C25ir:in012 4- nil,/)), which is bitter, but not poisonous ; and 
anamirtin (C19lI24O10), which is neither bitter nor poisonous. 
Salicin (CiSH1807).—This substance (Salicinum, U. S. P.) 
is contained in and easily extracted from the bark of the 
willow, Salix alba, and from other species of Salix (Salix, 
U. S. P.), especially from Salix helix. 
Tests.—1. To a small portion of salicin placed on a white THE GLUGOSIDES. 
423 
plate or dish add a drop of strong sulphuric acid; a deep red 
color is produced. 
2. Boil salicin with dilute sulphuric acid for some time; it 
is converted into su igenin (C7HB02) and glucose. 
C.AA + H20 - C7HA + CfiH,A 
Salicin. Water. Saligenin. Glucose. 
Examine a portion of the solution for grape-sugar by the 
copper-test. 
3. To another portion of the liquid, carefully neutralized, 
add a persalt of iron ; a purplish-blue color is sometimes pro- 
duced, due to the reaction of the saligenin and the ferric salt* 
The saligenin is, however, so rapidly decomposed by acids into 
safiretin (C7H#0) and water that this reaction is almost value- 
less as a test. Saligenin may readily be obtained by action of 
synaptase on salicin. 
4. Heat a mixture of about 1 part of salicin, 1 of red chro- 
mate of potassium, 12 of sulphuric acid, and 20 of water in a 
test-tube ; a fragrant characteristic odor is evolved, due to the 
formation of hydride of salicyl (C7H50,H), an essential oil 
identical with that existing in meadow-sweet (JSpirsea ulmaria.) 
and in heliotrope. 
2C7H802 + 02 = 2C7H,OJI + 211,0 
Saligenin. 
Oxygen. 
Hydride of 
salicyl. 
Water. 
Santonin (0I5II1803).—This substance is apparently the anhydride 
of a weak acid (Hesse), insoluble in ammonia, but forming a soluble 
calcium salt. Indeed, by boiling santonin for twelve hours with 
baryta-water, Cannizarro has obtained a salt from which hydrochlo- 
ric acid separates santanic acid. Santoninate of Sodium (Sodii 
Santoninas, U. S. P.) has the formula 2NaC15H1904,711.20, and occurs 
in colorless crystals unstable when exposed to light. From a solu- 
tion of santonate of calcium the santonin is precipitated by acids. 
Boiled for some time with dilute sulphuric acid, it yields 87 per 
cent, of an insoluble resinous substance (santoniretin) and glucose 
(Kosmann). Santonin (Satoninum, U. S. P., and Trochischi Sodii 
Santoninatis, U. S. P.) is official. It is soluble in an aqueous solu- 
tion of twice its weight of carbonate of sodium. 
Process.—The process for its preparation consists in boiling San- 
tonica. U. S. P. (the unexpanded flower-heads of Artemisia maritima, 
U. S. P., or Levant Worm seed), with milk of lime (whereby santonate 
of calcium is formed), straining, precipitating the santonin or san- 
tonin acid by hydrochloric acid or acetic acid, washing with ammo- 
nia to remove resin, dissolving in spirit, and digesting with animal 
charcoal to get rid of coloring-matter, setting the spirituous solution 
aside to deposit crystals of santonin, and purifying by recrystalliza- 
tion from spirit (Mialhe). 
Test.—To highly dilute solution of perchloride of iron add an equal 424 
AMYLACEOUS AND SACCHARINE SUBSTANCES. 
bulk of concentrated sulphuric acid. To this reagent add the san- 
tonin, or powder or substance suspected to be santonin, and cau- 
tiously apply heat. A red purple, and finally violet, color is pro- 
duced (Lindo). Santonin added to warm alcoholic solution of potash 
yields a violet-red color. 
Tanacetic acid, from the leaves and tops of Tanacetum vulgarc, or 
Tansy (Tanacetum, U. S. P.), is a yellow crystalline acid having the 
medicinal properties of santonin. 
Saponin (Cl2II20O7?) is a peculiar glucoside occurring in Soap- 
wort, the root of the common Pink, and many other plants ; its 
solution in water, even though very dilute, froths like a solution of 
soap. Pereira considers smilacin (Salseparin or Parallin), one of 
the principles of the supposed activity of the root of Smilax officinalis, 
or Sarsaparilla (Sarzce Radix, B. P., Sarsaparilla, U. S. iJ.), to be 
closely allied to, if not identical with, saponin. 
Saponin is also met with in the root of Polygala senega (Senega, 
U. S. P.), though the active principle of senega is said to reside in 
polygalic acid, probably a glucosidic derivative of saponin. 
According to Klunge (Pharmacographia), parallin, by action of 
acids, yields parigenin. The aqueous solutions of parallin froth 
when shaken. 
Saponin is readily obtained from the bark of Quillaia saponaria, 
or Soap-bark (Quillaia, U. S. P.), by boiling the aqueous extract in 
alcohol and filtering while hot. Flocks of saponin separate on cool- 
ing. It is a white, non-crystalline, friable powder. 
Scammonin (C:uHr,fi016).—Boil resin of scammony (Resina 
Scammonii, U. S. P.) with dilute sulphuric acid for some time ; 
glucose may then be detected in the liquid, a resinous acid 
termed scammoniol (Cull1303 ?) being produced at the same 
time. 
Natural scammony (Scammonium, U. S. P.) is an exudation from 
incisions in the living root of Convolvulus scammonia. It contains 
from 10 to 20 per cent, of gum, and therefore, when rubbed up with 
water, gives an emulsion. “ Ether removes from 80 to 90 per cent, 
of resin ” (B. P.). The official resin of scammony contains no gum, 
and therefore gives no emulsion when rubbed up with water. It is 
made by digesting the root in spirit, distilling off the alcohol, and 
washing the residual resin with water till free from the gum. There 
seems to be little or no chemical difference between the extracted 
resin and the resin of the exuded scammony. 
Resin of scammony is soluble in all proportions in ether. Spir- 
gatis states that it is identical with the resin of Mexican Male Jalap, 
which also is soluble in ether. Sulphuric acid slowly reddens it. It 
is said to be liable to adulteration with resin of true jalap, guaiacum 
resin, and common rosin. Resin of true jalap is insoluble in ether; 
guaiacum resin is distinguished by the color-test mentioned under 
Guaiacin, and rosin by the action of sulphuric acid. 
Scillitin.—Schroff, and, afterward, Riche and Remont, believed 
the bitter principle of the squill-bulb (Scilla, U. S. P.) to be a glu- ALCOHOL. 
425 
coside. Merck has extracted substances which he has termed scil- 
lipicrin and scillitoxin. But no definite crystalline principle has yet 
been obtained. Schmeideberg has given the name sinistrin to a 
squill principle. Squill contains a large quantity of mucilage. 
The bulbous root of Crinum asiaticum is official in the Pharma- 
copoeia of India (Crini Radix, P. I.) as a substitute for squill. It 
has not been chemically investigated. 
739. Define glucosides, and mention those of pharmaceutical 
interest. 
740. Draw out an equation illustrative of the development of Oil 
of Bitter Almonds. 
741. How much pure amygdalin will yield one grain of real hydro- 
cyanic acid ? 
742. To what does Cherry-Laurel water oavc its activity? Is the 
preparation trustworthy ? 
743. Mention the active principle of Senna. 
744. By what process is the glucosidc of the purple foxglove 
prepared ? 
745. State the circumstances under which Guaiacum Resin and 
Jalap Resin yield glucose. 
746. Mention a test for guaiacum resin. 
747. How may the adulteration of jalap resin by rosin be de- 
tected ? 
748. Enumerate the tests for Salicin. 
749. How is santonin officially prepared? 
750. Name sources of saponin. 
751. What is the difference between Scammony and Resin of 
Scammony ? 
752. IIow would you detect resins of turpentine, guaiacum, or 
jalap in resin of scammony ? 
QUESTIONS AND EXERCISES. 
ALCOHOL AND ALLIED BODIES. 
ALCOHOL, OR HYDRATE OF ETHYL. 
Formation of Alcohol.—Ferment two or three grains of sugar by 
dissolving in a test-tube full of water, adding a little yeast (Cere- 
yisice Fermentum, B. 1’.) or a piece of the so-called German or dried 
yeast, and set the whole aside for several hours in a warm place at 
a temperature of 70° or 75°; carbonic acid gas is evolved, and, if 
the tube be inverted in a small dish containing water, may be col- 
lected in the upper part of the tube and subsequently tested: the 
solution contains alcohol. If the experiment be made on larger 
quantities (4 ounces of sugar, 1 of yeast, and 1 pint of water) the 
fermented liquid should be distilled, one-half being collected, shaken 
with a little lime, soda, or potash, to neutralize any acetic acid and 426 
ALCOHOL AND ALLIED BODIES. 
decompose ethereal salts, and again distilled till one-half has passed 
over; the product is dilute spirit of wine. It may be still further 
concentrated or rectified by repeating this process of fractional dis- 
tillation. 
Fermentation.—The act of fermentation is commonly the result, 
or rather accompaniment, of some vital action. Alcoholic fermentation 
would appear to be always attended by or to attend development of 
life and free multiplication of cellular structure. It follows the de- 
velopment of the fungus already referred to as constituting the 
chief active part of yeast, the Saccharomyccs cerevisice. In the 
presence of this fungus, with small quantities of phosphates and 
albumenoid matter, glucose is converted into alcohol and carbonic 
acid gas, together with small proportions of glycerin, succinic acid, 
and other substances. Yeast also contains a soluble ferment anal- 
ogous to diastase, which is capable of converting sucrose into 
glucose. Therefore, if yeast be used, sucrose or cane-sugar may 
be converted into carbonic acid gas and alcohol, the soluble ferment 
first converting the sucrose into glucose. 
C6IT1206 = 2C2H5HO + 2C02 
Grape-sugar. 
Alcohol. 
Carbonic 
acid gas. 
Not more than 20 per cent, by weight of alcohol can be obtained 
in a fermenting fluid, for more than this proportion prevents fer- 
mentation. 
Other kinds of fermentation, arising from the action of special 
ferments which have not received in all cases distinctive names, are 
the following: Viscous or Mannitic fermentation, which occurs when 
beer or saccharine juices, such as that of beet-root, become “ropy.” 
Gum, mannite, and carbonic acid gas are produced. For Lactic and 
Butyric fermentations see Lactic Acid. Putrefactive fermentation 
occurs when a liquid containing albumenoid matter is exposed to 
the air. Infusoria appear in the liquid, using up the dissolved 
oxygen, and the ferments of the genus Vibrio are developed. Those 
are protected from oxygen, which is fatal to them, by a thin surface- 
layer crowded with bacteria—small rod-like organisms having powers 
of locomotion. The vibrionic action, or putrefaction, proceeds with 
evolution of sulphuretted hydrogen, together with other gases having 
unpleasant odors and of complex chemical constitution. For Acetic 
fermentation see Acetic Acid. For Ammoniacal fermentation, see 
Urine. 
Fermentation by Certain Soluble Albumenoids.—For the conversion 
of starch into sugar by diastase, see Starch; of amygdalin into ben- 
zoic aldehyd, hydrocyanic acid, and glucose by emulsin, see Amyg- 
dalin ; of salicin into saligenin and glucose, see Salicin; of myronate 
of potassium into sulphocyanide of allyl, etc. by myrosin, see Mus- 
tard ; of cane-sugar into grape-sugar by the soluble ferment in yeast, 
see the foregoing paragraphs. 
Alcoholic Fermentation.—The chief reaction results, as already 
stated, in the formation of alcohol and carbonic acid gas, though 
traces of several other substances are simultaneously produced (vide ALCOHOL. 
427 
“Fusel Oil” in Index). By this reaction are formed the spirit of 
the various kinds of wine, beer, and liqueurs: Sherry Wine (Vinum 
Xericum, B. P.) and Port Wine, the fermented juice of the grape; 
Whiskey (Spiritus Frumenti, U. S. P.), containing from 48 to 56 per 
cent, of pure alcohol; Spirit of Mi/rcia, or Bay Rum (Spiritus 
Myrcice, U. S. P.), prepared by dissolving the oils of Myrcia acris, 
pimento, and orange-peel in diluted alcohol; and others. 
Alcoholic drinks vary much in strength. Cider or apple wine, 
cherry or pear wine, and good beer (ale and porter, or stout) contain 
4 to 6 per cent, of real alcohol; good light wines, both “red” and 
“ white,” 10 to 12 per cent.; good sherry and port, which are com- 
monly “ fortified”—that is, contain added spirit—16 or 18 per cent.; 
while “spirits” (gin, rum, brandy, whiskey, etc.) and “liqueurs” 
(ratafia, almond-flavored; maraschino, cherry-flavored; curaqoa, 
orange-flavored; chartreuse, a composite-flavored liqueur, etc.) are 
“under proof” or “over proof,” terms explained in the next para- 
graph. The well-known effects of these fluids on the animal system 
would appear to be due primarily to alcohol, and, secondarily, to 
ethereal derivatives of alcohols. Some owe a part of their effects to 
non-volatile substances, for beer, from which all alcohol has been 
removed by ebullition, still has a powerful influence on the human 
economy. The official (U. S. P.) Wines are all made with “ Stronger 
White Wine” (Vinum Album Fortius, U. S. P.), made by adding 
1 part of alcohol to 7 parts of “White Wine” (Vinum Album, U. S. 
P.), the latter a kind of natural sherry containing not less than 10 
nor more than 12 per cent, of absolute alcohol. Vinum Rubrum, 
U. S. P., is of similar strength—a kind of natural port wine. 
Varieties of Alcohol.—The weak spirit concentrated by distilla- 
tion till it contains 84 per cent, by weight of pure alcohol is an 
ordinary article of British trade; its specific gravity at 60° F. is 
0.8382. This is common Spirit of Wine, the Spiritus Rectificatus 
of the British Pharmacopoeia. The British official Proof Spirit* 
(Spiritus Tenuior, B. P.) contains 49 per cent, by weight of alcohol, 
and is made by diluting 100 volumes of Rectified Spirit with water 
until the well-stirred product measures 156 volumes. Sixty volumes 
of water will be required for this purpose, the liquids occupying 
less bulk after than before admixture. In the language of the 
Excise authorities, the rectified spirit of the Pharmacopoeia would be 
described as “56 per cent, over proof” (56 per cent. O. P.); that 
is, 100 volumes contain as much alcohol as is present in 156 volumes 
of proof spirit. Obviously, proof spirit may be made by diluting 
with water rectified spirit of any other strength than that mentioned 
above. Thus 100 fluidounces of a spirit of “ seventy over proof” 
may be diluted to 170, or the same quantity of a spirit of “fifty 
* Proof spirit is so termed from the fact that in olden times a proof 
of its strength was supposed to he afforded by moistening a small 
quantity of gunpowder and setting light to the spirit; if it fired the 
powder, it was said to be “over proof;” if not, “under proof.” The 
weakest spirit that would stand this test was what we should now 
describe as of sp. gr. 0.920. 428 
ALCOHOL AND ALLIED BODIES. 
over proof” may be diluted to 150, and so on. The specific gravity 
of proof spirit at 60° is 0.920. 
Alcohol, U. S. P., contains 91 per cent, by weight (94 by volume), 
Alcohol Dilutum, U. S. P., 45£ per cent, by weight (53 by volume) 
of real alcohol, the remainder being water. The former has a sp. 
gr. of 0.820, the latter 0.928, at 15.6° C., or 0.812 and 0.920, re- 
spectively, at 25° C. The stronger boils at 78° C. 
Empirical Formula}—Composition of Alcohol.—Alcohol by quanti- 
tative analysis is found to contain the elements carbon, hydrogen, 
and oxygen in the following proportions :— 
Composition of Alcohol. 
Carbon . . . 52.174, or 12 = 4.348, or 2. 
Hydrogen . . . 13.043, or h- 1 = 13.043, or 0. 
Oxygen . . . 34.783, or 16 = 2.174, or 1. 
100.000 
From centesimal numbers a formula is obtained in the usual way. 
Thus, on dividing these figures by the atomic weights of the respec- 
tive elements (C = 12, II = 1, 0 = 16), and reducing the products 
to the simplest whole numbers, alcohol will he found to contain two 
atomic weights of carbon to every six of hydrogen and to every one 
of oxygen, and its possible or empirical formula to he C2lIfiO. 
Constitution of Alcohol.—There is good reason to believe that 
alcohol is the hydrate of a hasylous radical ethyl (02II5 or Et) ; hence 
we derive the rational formula C2II5IIO or EtllO. Sodium displaces 
hydrogen from alcohol, ethylate of sodium, or “caustic alcohol,” 
being produced: Na2 + 2EtlIO — Il2 + 2EtNaO. 
Rational Formula’.—Rational formulae are deduced by (1) ascer- 
taining how much of the substance will combine with, displace, or 
play the part of, the atomic weight of a well-known element or 
radical. When this method cannot be applied, or in confirmation 
of it, processes of (2) reduction, (3) oxidation, (4) substitution, etc. 
arc employed. 
Salts of Ethyl.—Alcohol is, then, a body analogous in constitu- 
tion to hydrate of potassium (K1IO) ; and there are other compounds 
of ethyl analogous in constitution to ordinary inorganic salts, such 
as those of potassium. The oxide of ethyl (Et20) is common ether; 
the nitrite of ethyl (EtN02) is the chief body which, dissolved in 
spirit of wine, constitutes “ sweet spirit of nitrethe acid sulphate 
of ethyl (EtHSOJ, or sulphethylic or sulphovinic acid, is a liquid 
met with in the preparation of ether. The iodide (EtI), hydride 
(EtII), acetate (EtA), and other salts are of considerable chemical 
interest, but not used in medicine. 
Absolute or Real Alcohol (C2II5IIO) may be prepared from spirit 
of wine by removing the water which the latter contains. This is 
accomplished, partially, by anhydrous carbonate of potassium, and 
finally and entirely by recently-burned quicklime. In operating on, 
say, one pint, la ounces of dried carbonate of potassium are placed 
in a bottle that can be well closed, and frequently shaken during ALCOHOL. 
429 
two days with the spirit. Meanwhile, about half a pound of good 
quicklime, if not already at hand, is made from 10 or 11 ounces of 
slaked lime by heating to redness in a covered crucible for half an 
hour. The spirit having been decanted from the denser aqueous 
solution of carbonate of potassium and placed in a quart flask, re- 
tort, or tin can, the lime, as soon as cold, is added, and the whole 
occasionally shaken during a day. The vessel is now placed in a 
saucepan or other bath containing water, quickly connected with 
a condenser (in the case of the flask or can by a bent tube and cork 
previously prepared, for absolute alcohol must not be exposed to 
air, or water in the form of moisture will be rapidly reabsorbed), 
and heat applied to the bath. Rejecting the first ounce or ounce 
and a half, as likely to contain traces of moisture absorbed 
from the air or apparatus, continue distillation until nothing 
more passes over, the water in the bath being kept just below 
the boiling-point (about 200° F.). These details are those of 
the British Pharmacopoeia. Specific gravity 0.7938 ; boiling-point, 
Tests.—There are no specific tests for alcohol when mixed with 
complex matters. It is, however, easily isolated and concentrated 
by fractional distillation, and is then recognizable by conjoint physi- 
cal and chemical characters. Thus its odor and taste are character- 
istic ; it is lighter than water, volatile, colorless, and, when tolerably 
strong, inflammable, burning with an almost non-luminous flame ; it 
readily yields aldehyd (see below) and acetic ether (vide p. 436), 
each of which has a characteristic odor; lastly, in presence of hot 
acid, alcohol reduces red chromate of potassium to a green salt of 
chromium. 
According to Lieben, 1 of alcohol in 2000 of water can be detect- 
ed by adding to some of the warmed liquid a little iodine, a few 
drops of solution of soda, again warming gently, and setting aside 
for a time; a yellowish crystalline deposit of iodoform (C1II3) is 
obtained. Under the microscope the latter presents the appearance 
of hexagonal plates or six-rayed and other varieties of stellate 
crystals. 
C2H60 + 4I2 + 6NaIIO = CIII3 + NaCH02+ 5NaI + 5II20. 
Other alcohols, aldehyds, gum, turpentine, sugar, and several other 
substances give a similar reaction. 
Tests of Purity.—Oil or resin is precipitated on diluting spirit of 
wine with distilled water, giving an opalescent appearance to the 
mixture. The specific gravity should be 0.838. Fusel oil, aldehyd, 
and such impurities are detected by nitrate of silver (vide Index, 
“Alcohol, Test for Purity of”). Water in absolute alcohol may be 
detected by adding to a small quantity a little highly dried sulphate 
of copper, which becomes blue (CuS04,5II20) if water is present, 
but retains its yellowish-white anhydrous character (CuS04) if water 
be absent. In the United States Pharmacopoeia it is laid down that 
alcohol, “ if mixed with its own volume of water and one fifth its 
volume of glycerin, a piece of blotting-paper, on being wet with the 
mixture after the vapor of alcohol has wholly disappeared, should 430 
ALCOHOL AND ALLIED BODIES. 
give no irritating or foreign odor (fusel oil). And if a portion be 
evaporated to one-fifth its volume, the residue should not turn red- 
dish upon the addition of an equal volume of sulphuric acid (amyl 
alcohol). When treated in a test-tube with an equal volume of solu- 
tion of potassa, there should not be an immediate darkening of the 
liquid (methyl alcohol, aldehyd, and oak tannin). If a portion of 
about 150 c.c. be digested for an hour with 20 gm. of carbonate of 
lead, and filtered, the filtrate then distilled from a water-bath, and 
the first 20 c.c. of the distillate treated with 1 c.c. of test-solution 
of permanganate of potassium, the color should not disappear within 
one or two minutes (abs. of methyl alcohol).” 
Aldeiiyd (CJI40).—Place together, in a capacious test- 
tube, or a flask, about four parts of spirit of wine, six of black 
oxide of manganese, six of sulphuric acid, and four of water, 
and gently warm the mixture; aldehyd (afcohol cie/o/t/rogen- 
atus), a highly volatile liquid, is immediately formed, and its 
vapor evolved, recognized by its peculiar, somewhat fragrant 
odor. Adapt a cork and rather long bent tube to the test-tube, 
and let some of the aldehyd slowly distil over into another test- 
tube, the condensing-tube being kept as cool as possible. Set 
the distillate aside for a day or two; the aldehyd will have 
nearly all disappeared, and acetic acid be found in the tube. 
Test the exposed liquid by litmus-paper; it will be found to 
have an acid reaction : make it slightly alkaline by a drop or 
two of solution of carbonate of sodium, then boil to remove any 
alcohol and aldehyd present, add sulphuric acid, and notice the 
characteristic odor of the acetic acid evolved. 
These experiments will enable the process of Rectification described 
in connection with acetic acid to he more fully understood. Pure 
diluted alcohol is not oxidized by exposure to air; but in presence 
of fermentive matter, or vegetable matter undergoing decay or change, 
it is oxidized first to aldehyd and then to acetic acid. 
In the above process the black oxide of manganese and sulphuric 
acid furnish nascent oxygen :—■ 
Black oxide 
of manganese. 
MnO, + II2S04 = M n SO, + 0 + II20. 
Sulphuric 
acid. 
Sulphate of 
manganese. 
Oxygen 
(atom). 
Water. 
The nascent oxygen then acts on the alcohol, just as the oxygen of 
the air acts on the alcohol in fermented infusion of malt, beer, or 
wine, giving aldehyd :— 
C,JT,.0 + 0 = C,,1T40 + II.20 
Alcohol. 
Oxygen 
(atom). 
Aldehyd. 
Water. 
The aldehyd rapidly, even when pure (more rapidly when impure), 
absorbs oxygen and yields acetic acid:— 
2CJI.0 + 02 = 20,11,0, 
Aldehyd. Oxygen. Acetic acid. 
Tests.—Aldehjd heated with solution of potash gives a brownish- ALCOHOL. 
431 
yellow resinous mass of peculiar odor. Its aqueous solution re- 
duces salts of silver, giving a mirror-like coating to the sides of a 
test-tube. 
Spirit of French Wine (Spiritus Vini Gallici, U. S. P.), or Brandy, 
is a colored and flavored variety of alcohol distilled from French 
wine. Its color is that of light sherry, and is derived from the cask 
in wrhieh it has been kept, but it is commonly deepened by the addi- 
tion of burnt sugar. Its taste is due to the volatile flavoring con- 
stituent of the wine, often increased by the addition of artificial 
essences. u Brandy has a pale amber color, a distinctive taste and 
odor, and a sp. gr. not above 0.941 nor below 0.925, corresponding 
approximately with an alcoholic strength of 39 to 47 per cent, by 
weight, or 40 to 55 per cent, by volume. If 100 c.c. of brandy be 
slowly evaporated in a weighed capsule, on a water-bath, the last 
portions volatilized should have an agreeable odor, free from harsh- 
ness (abs. of fusel oil from grain or potato spirit). The resi- 
due, dried at 100° C. (212° F.), should weigh not more than 
0.250 gin., equivalent to 0.25 per cent. (abs. of an undue amount 
of solids). This residue should have no sweet or distinctly spicy 
taste (abs. of added sugar, glycerin, or spices). It should nearly all 
dissolve in 10 c.c. of cold water, forming a solution which is colored 
light green by a dilute solution of ferric chloride (traces of oak 
tannin from casks). 100 c.c. of brandy should be rendered dis- 
tinctly alkaline to litmus by 3 c.c. of the volumetric solution of 
soda (abs. of an undue amount of free acid).”—IT. S. P. 
The foregoing words are also used in describing Whiskey (Spiritus 
Frumenti) in the United States Pharmacopoeia, except that the sp.gr. 
is to be “ not above 0.930 nor below 0.917, corresponding approx- 
imately with an alcoholic strength of 44 to 50 per cent, by weight, 
or 50 to 58 per cent, by volume,” and that the acidity is not to be 
greater in 100 c.c. than 2 c.c. of soda solution will neutralize. 
753. Write a few sentences on the formation, purification, and 
concentration of alcohol, and explain the difference between Recti- 
fied Spirit, Proof Spirit, and Absolute Alcohol. 
754. What quantity of water must be added to one gallon of 
spirit of wine, 56 degrees over proof, to convert it into proof 
spirit ? 
755. To what volume must 5 pints of spirit of wine of 53 degrees 
over proof be diluted before it becomes proof spirit? Ans. 7 pints, 
13 ounces. 
756. State the specific gravity of proof spirit. 
757. Show how the formula of alcohol is obtained from its cen- 
tesimal composition:— 
Carbon 52.174 
Hydrogen 13.043 
Oxygen J54.783 
100.000 
QUESTIONS AND EXERCISES. 432 
ALCOHOL AND ALLIED BODIES. 
758. Give the formulae of some of the salts of ethyl. 
759. By what processes may pure hydrate of ethyl be obtained? 
760. Enumerate the characters of alcohol. 
761. Mention a chemical test to distinguish rectified spirit from 
absolute alcohol. 
762. From the formula of aldehyd calculate back its composition 
in 100 parts. 
763. What is the relation of aldehyd to alcohol and to acetic 
acid ? 
764. Whence is brandy obtained, and to what are due its color 
and flavor? 
ETHER, OR OXIDE OF ETHYL. 
Formula C4H10O, or (C2H5)20, or Et20. 
Experimental Process.—Into a capacious test-tube put a 
small quantity of spirit of wine and about half its bulk of sul- 
phuric acid, mix and gently warm; the vapor of ether, recog- 
nized by its odor, is evolved. Adapt a cork and long bent tube 
to the test-tube, and slowdy distil over the ether into another 
test-tube. Half the original quantity of alcohol now placed in 
the generating-tube will again give ether; and this operation 
may be repeated many times. 
On the larger scale, and according to the following process, the 
addition of alcohol, instead of being intermitting, is continuous, a 
tube conveying alcohol from a reservoir into the generating-vessel. 
Mix 10 fluidounces of sulphuric acid with 12 fluidounces of rectified 
spirit in a glass retort or flask capable of containing at least two 
pints, and, not allowing the mixture to cool, connect the retort or 
Fig. 49. 
flask by means of a bent glass tube with a Liebig’s condenser, and 
distil with a heat sufficient to maintain the liquid in brisk ebulli- 
tion. If a thermometer also be inserted in the tubulure of the ETIIYLIC ETHER. 
433 
retort or through the cork of the flask, the temperature may he still 
more carefully regulated—between 284° and 290° F. As soon as 
the ethereal fluid begins to pass over, supply fresh spirit in a con- 
tinuous stream, and in such quantity as to about equal the volume 
of the fluid which distils. For this purpose use a tube furnished 
with a stopcock to regulate the supply, connecting one end of the 
tube with a vessel containing the spirit supported above the level 
of the retort or flask, and passing the other end through the cork 
of the flask into the liquid. When a total of 50 fluidounces of 
spirit has been added, and 42 fluidounces of ether have distilled 
over, the process may be stopped. 
To partially purify the liquid, dissolve 10 ounces of chloride of 
calcium in 13 ounces of water, add half an ounce of lime, and agi- 
tate the mixture in a bottle with the impure ether. Leave the 
mixture at rest for ten minutes, pour off the light supernatant 
fluid, and distil it with a gentle heat until a glass bead of specific 
gravity 0.735 placed in the receiver begins to float. The ether and 
spirit retained by the chloride of calcium and by the residue of each 
rectification may be recovered by distillation and used in a subse- 
quent operation. 
Explanation of Process.—On the addition of sulphuric acid to 
alcohol in equal volumes, one molecule of each reacts and gives a 
molecule of sulphethylic acid and one of water:— 
EtTIO + H2S04 = EtTIS04 + 11,0 
Alcohol. 
Sulphuric 
acid. 
Sulphethylic 
acid. 
Water. 
More alcohol then gives ether and sulphuric acid by the reaction of 
one molecule of the alcohol on one of sulphethylic (ethylsulphuric) 
acid:— 
EtTIO + EtIISO, = Et20 + II2S04 
Alcohol. 
Sulphethylic 
acid. 
Ether. 
Sulphuric 
acid. 
The water of the first reaction and the ether of the second distil 
over, while the sulphuric acid, as fast as liberated, is attacked by 
alcohol and reconverted into sulphethylic acid:— 
EtllO + 11,80, = EtHS04 + H20 
Alcohol. . Sulphuric Sulphethylic Water, 
acid. acid. 
so that the sulphuric acid originally employed finally remains in the 
retort in the form of sulphethylic acid. The effect, however, of a 
small quantity of sulphuric acid in thus converting a large quantity 
of alcohol into ether is limited, secondary reactions occurring to 
some extent after a time. 
Properties.—Pure ether is gaseous at temperatures above 95° F.; 
hence the condensing-tubes employed in its distillation must be kept 
as cool as possible. At all ordinary temperatures it rapidly evapor- 
ates, absorbing much heat from the surface on which it is placed. 
A few drops evaporated consecutively from the back of the hand 
produce great cold; if blown in the form of spray, the cooling effect 
is so rapid and intense as to produce local anaesthesia. Its vapor is 434 
ALCOHOL AND ALLIED BODIES. 
very heavy, more than twice and a half that of air and nearly forty 
times that of hydrogen (H2 = 2; C4II10O = 74; or as 1 to 37). In 
a still atmosphere, therefore, it will flow a considerable distance 
along a table or floor before complete diffusion occurs; the vapor 
is also highly inflammable; hence the importance of keeping candle 
and other flames at a distance during manipulations with ether. 
Purification.—To imitate the process of partial purification 
above described, add to the small quantity of ether obtained in 
the foregoing operation a strong solution of chloride of calcium 
and a little slaked lime; the latter absorbs any sulphurous acid 
that may have been produced by secondary decompositions, 
while the former absorbs water; on shaking the mixture and 
then setting aside for a minute or two, the ether will be found 
floating on the surface of the solution of chloride of calcium. 
This ether, redistilled until the distillate has a sp. gr. not higher 
than 0.735 and boiling-point not higher than 105° F., is the ether 
of the British Pharmacopoeia. It still contains about 8 per cent, of 
alcohol. The latter may be removed by well shaking the ether with 
half of its bulk of water, setting aside, separating the floating ether, 
and again shaking it with water ; alcohol is thus washed out. This 
washed ether, containing water (for water and ether are to some 
extent soluble the one in the other; 50 measures agitated with an 
equal volume of water are reduced to 45 by an absorption of 10 per 
cent.), is next placed in a retort with solid chloride of calcium and 
a little caustic lime, and once more distilled ; pure dry ether results. 
Sp. gr. not exceeding 0.720. JEther, U. S. P., contains nearly 74 per 
cent, of real ether, nearly 26 per cent, of alcohol, and a little water; 
sp. gr. 0.750 at 15° C. JEther Fortior, U. S. P., contains nearly 94 
per cent, of real ether, nearly 6 per cent, of alcohol, and a little 
water; sp. gr. not above 0.725 at 15° C., or 0.716 at 25° C.; boiling- 
point, 37° C. Agitated with an equal volume of glycerin, the JEther 
should yield 75 per cent, of ether, while Ether Fortior should yield 
86 per cent. 
Spiritus JEthei'is, U. S. P., is a mixture of 30 weights of ether 
with 70 similar weights of alcohol. Spiritus Jit her is Compositus, 
U. S. P., contains 30 of stronger ether, 67 of alcohol, and 3 of ethe- 
real oil. It is the old “ Hoffmann’s Anodyne.” 
NITROUS ETHER, OR NITRITE OF ETHYL. 
Formula C2H3N02 or EtN02. 
Process.—To a third of a test-tubeful of alcohol add about 
a tenth of its bulk of sulphuric acid, rather more of nitric 
acid, and warm the mixture as soon as ebullition commences; 
the vapor of nitrous ether (with other substances) is evolved, 
recognized by its odor. A long bent tube, kept cool, may be 
adapted by a perforated cork to the test-tube, and thus a little 
of the product be condensed and collected. NITROUS ETHER. 
435 
The above process conducted on a larger scale, with definite quan- 
tities of materials, temperature regulated by a thermometer, and a 
well-cooled condenser, etc. (see p. 125), is the official process for the 
preparation of a solution of crude nitrous ether. Diluted with spirit, 
one variety of it forms the “sweet spirit of nitre” (Spiritus JEtheris 
Nitrosi, U. S. P.) of pharmacy, “ containing 5 per cent, of the crude 
ether.” 
“Add 7 parts of sulphuric acid gradually to 31 parts of alcohol. 
When the mixture has cooled, transfer it to a tubulated retort con- 
nected with a well-cooled condenser, to which a receiver, surrounded 
by broken ice, is connected air-tight, and which is further connected, 
by means of a glass tube, with a small vial containing water, the end 
of the tube dipping into the latter. Now add 9 parts of nitric acid 
to the contents of the retort, and, having introduced a thermometer 
through the tubulure, heat rapidly, by means of a water-bath, until 
strong reaction occurs and the temperature reaches 80° C. (176° F.). 
Continue the distillation at that temperature, and not exceeding 82° 
C. (180° F.), until the reaction ceases. Disconnect the receiver, and 
immediately pour the distillate into a flask containing 16 parts of 
ice-cold distilled water. Close the flask and agitate the contents 
repeatedly, keeping down the temperature by immersing the flask 
occasionally in ice-water. Then separate the ethereal layer and 
mix it immediately with 19 times its weight of alcohol. Keep the 
product in small, glass-stoppered vials, in a dark place, remote from 
lights or fire.” 
“ Properties.—A clear, mobile, volatile, and inflammable liquid, of 
a pale straw-color, inclining slightly to green, a fragrant, ethereal 
odor, free from pungency, and a sharp, burning taste. Sp. gr. 0.823 
to 0.825. It slightly reddens litmus-paper, but should not effervesce 
when a crystal of bicarbonate of potassium is dropped into it. When 
mixed with half its volume of solution of potassa, previously diluted 
with an equal volume of water, it assumes a yellow color, which 
slightly deepens, without becoming brown, in twelve hours. A por- 
tion of the spirit, in a test-tube half filled .with it, plunged into 
water heated to 63° C. (145.4° F.), and held there until it has ac- 
quired that temperature, should boil distinctly on the addition of a 
few small pieces of glass. 
“ Test.—If 10 gm. of spirit of nitrous ether be macerated with 1.5 
gm. of potassa for twelve hours, with occasional agitation, the mix- 
ture then diluted in a beaker with an equal volume of water, and 
set aside until the odor of alcohol has disappeared, then slightly 
acidulated with diluted sulphuric acid, and a solution of 0.335 gm. 
of permanganate of potassium gradually added, the color of the 
whole of this solution should be discharged (presence of at least 4 
per cent, of real ethyl nitrite).” 
The nitrous radical may be detected by adding sulphate of iron 
and sulphuric acid to some of the spirit of nitrous ether, a brown 
or black compound being produced, already explained in connection 
with nitric acid (p. 286). 
The chief reactions in the above process consist in the reduction 
of the nitric radical (N03) to the nitrous (N02) by some of the hot 436 
ALCOHOL AND ALLIED BODIES. 
spirit, and the combination of the nitrous radical with the ethyl of 
more of the spirit. 
Acetic Ether, or Acetate of Ethyl. 
To a little dried acetate of sodium, in a test-tube, add a 
small quantity of rectified spirit of wine and some sulphuric 
acid, and, adapting a long bent tube in the usual manner, heat 
the test-tube, and so distil over acetic ether, which may be 
collected in another test-tube kept cool by partial immersion in 
cold water. 
The official proportions (./Ether Aeeticus, B. P.) are 8 parts of 
dried acetate of sodium, 5 of spirit, and 10 of acid. It is purified 
from any water by shaking in a bottle with fused chloride of calcium, 
and, after twenty-four hours, rectifying. “ Sp. gr. 0.910. Boiling- 
point 166° F.” 
C2H£HO + NaC2H302 + II2S04 = C2II5C2U302 -f Nail SO, 
Hydrate of 
ethyl. 
Acetate of 
sodium. 
Sulphate of 
hydrogen. 
Acetate of 
ethyl. 
Sulphate of sodium 
aud hydrogen. 
+ H,0 
Water. 
The JEther Aeeticus, U. S. P., has a sp. gr. of 0.889 to 0.897 ; 
boiling-point 76° C. (168.8° F.). When 10 c.e. are agitated with an 
equal volume of water, in a graduated test-tube, the upper, ethereal 
layer, after its separation, should not measure less than 9 c.c. 
Iodide of Ethyl (EtI) may be prepared by mixing two or 
three parts of phosphorus with 100 of absolute alcohol, and 
then dropping in iodine gradually until about 200 parts have 
been added. 
Alcohol. 
5EtHO + PI5 = 5EtI + II:(P04 + H20 
Iodide of 
phosphorus. 
Iodide of 
ethyl. 
Phosphoric 
acid. 
Water. 
The reaction at first proceeds rapidly, and is complete after 
the mixture has been set aside for a few hours. The iodide of 
ethyl may then be isolated by careful distillation, freed from 
any excess of iodine by washing with a very small quantity of 
solution of potash or soda, washed with water, dried over chlo- 
ride of calcium, and again distilled. It should be kept in a 
dark place, as light favors decomposition and liberation of 
iodine. 
Bromide of ethyl (C2H5Br), or hydrobromic ether, may be 
similarly prepared. For its preparation on a large scale l)e 
Vrij’s method is preferable, EtHS04 + KBr = EtBr + 
KHS04 (see Pharm. Journ., Feb. 15, 1879), or the same 
method as modified by Greene (P. J., July 12, 1879) ; by ALCOHOL RADICALS. 
437 
Remington (P. ./., May 29, 1880); or by Wolff (P. J, July 
3, 1880). 
Ethyl.—This gaseous radical, (C2H5)2 or Et2, is obtained 
on digesting together, at about 250° F., in a strong sealed 
tube, dry, freshly granulated zinc with iodide of ethyl (Frank- 
land). 
Zn + 2EtI = Znl2 + Et2 
Zinc. 
Iodide of 
ethyl. 
Iodide of 
zinc. 
Ethyl. 
On cautiously opening the tube the ethyl escapes, and may be 
ignited or collected over water. There remains with the iodide 
of zinc a body termed by Frankland zinc-ethyl (ZnEt2) ; it is 
a spontaneously inflammable liquid, but may easily be distilled 
and otherwise manipulated if a few simple precautions be ob- 
served. If water be allowed to flow down the tube, the solid 
compound of iodide of zinc and zinc-ethyl will be decomposed, 
a gas, hydride of ethyl (EtH), resulting, which also may be in- 
flamed or collected over water :— 
ZnEt* + 211,0 = Zn2HO + 2EtH. 
765. Describe the official process for the preparation of Ether, 
giving equations. 
766. Offer a physical explanation of the mode of producing local 
anaesthesia. 
767. How is commercial ether purified? 
768. Explain the official process for the preparation of Spirit of 
Nitrous Ether. 
769. Give the properties of spirit of nitrous ether. 
770. By what official method is the strength of Spirit of Nitrous 
Ether estimated ? 
771. How is iodide of ethyl made? 
772. Adduce evidence of the existence of ethyl. 
QUESTIONS AND EXERCISES. 
OTHER ALCOHOL RADICALS AND THEIR SALTS. 
What has been stated concerning the chemistry of ethyl and its 
compounds may he applied to other radicals known to exist, some of 
the compounds of each of which are of common occurrence. These 
basylous radicals are closely related to each other, to hydrogen, and 
to the metals. Their formulae in the combined state may be built 
up by successive additions of CH2, thus:— ALCOHOL AND ALLIED BODIES. 
Ilydvogen 
. . . H 
Methyl 
. . . ('ll. 
or 
Me 
Ethyl 
• • • 
or 
Et 
Propyl (or Trityl) . . . 
Butyl (or Tetryl) . . . 
. . . ex, 
or 
or 
Pr 
Bu 
Amyl 
■ • • C5II„, 
or 
Ay 
Caproyl (or Hexyl) . . . 
• • • C6H,3, 
or 
Cp 
The above list is an illustration of an homologous series (from 
ogoQ, homos, the same, and ?.6yoc, logos, proportion) of compounds. 
It will be observed that the relation of the number of hydrogen atoms 
to carbon is twice as many, with one added ; hence the series is often 
termed the CnII2n+1 series (n — any number). The oxides of these 
radicals are known as ethers, their hydrates alcohols, their compounds 
with the acetic and similar acidulous radicals eihereal salts. Every 
alcohol furnishes a body corresponding to the aldehyd of spirit of 
wine, the class being termed aldehyds; each also yields an acid cor- 
responding with acetic acid. Any one of these classes constitutes 
an homologous series. Or, taking the hydride, oxide, hydrate, acid,, 
of any single radical, we get a heterologous (erepog, heteros, another) 
series of compounds. Hydride of methyl (Mell or CH3II) is ordi- 
nary marsh-gas, fire-damp or light carburetted hydrogen; it is a 
diluent or non-luminiferous constituent of ordinary coal-gas to the 
extent of 30 or 40 per cent. ;* formic acid, the acid of the methyl 
series; butyric acid, the acid of the butyl series • sulphocyanate of 
butyl, the essential oil of horseradish; valerianic acid, the acid of 
the amyl series. 
Homologous and Heterologous Series of the CBH2n-f1 Radicals. 
Radicals 
(free). 
Hydrides. 
Oxides 
(or ethers). 
Hydrates 
(or alco- 
hols). 
Aldehyds. 
Acids. 
(C h3 )2 
C H3 II 
(C II3 )20 
C II3 no 
C II2 0? 
C II, 0, 
(C,H5 )2 
C2II5 II 
(C,1I. )./> 
C,H. HO 
c2h4o 
c2ii4o, 
(C3H7)2 
C3II7II 
(C3ii7 )20 
C3II- HO 
c,h6 0 
<yi«o* 
(C4II,), 
c4h9h 
(C4II9 )20 
C4II9 IIO 
C41I80 
c*ii8o, 
(C5H„)2 
C*HnH 
(C.H„),0 
c5huiio 
C5H10O 
c5ii10o2 
etc. 
etc. 
etc. 
etc. 
etc. 
etc. 
* Coal-gas.—The other diluents, or vehicles for the conveyance of 
illuminating vapors of coal-gas, are hydrogen (40 to 50 per cent.) and 
carbonic oxide (6 to 7 per cent.). The illuminating constituents are 
olefiant gas (p. 453) and its homologues, existing to the extent of from 
5 to 7 per cent. Hydrocarbons normally fluid, but kept in the vapor- 
ous condition by the diluents, also contribute materially to the illu- 
minating power of gas. The impurities are nitrogen, air, carbonic 
acid, bisulphide of carbon, and badly-smelling sulphur compounds. METHYLIC ALCOHOL. 
439 
QUESTIONS AND EXERCISES. 
773. Mention several radicals homologous with ethyl, and give 
their formulae. 
774. Define ethers, hydrides, alcohols, ethereal salts, aldehyds. 
775. What is the difference between homologous and heterologous 
series ? 
776. Give the systematic name of fire-damp. 
777. Enumerate the chief constituents of coal-gas. 
778. State the formulae of formic, butyric, and valerianic acids. 
779. Write the formulae of butyl, its hydride, ether, alcohol, 
aldehyd, and acid. 
Methylic Alcohol (CII3IIO, or McIIO), Wood-Spirit, or Pyroxy- 
lic Spirit, or Wood-Naphtha, is a product of the destructive dis- 
tillation of wood. Spirit of wine containing 10 per cent, of wood- 
spirit constitutes ordinary methylated spirit, a spirit issued duty 
free for the use of manufacturers, the methylic alcohol not inter- 
fering with technical applications. From its nauseous taste and 
odor, however, it cannot take the place of gin, brandy, or other 
spirit; hence, while industry is benefited, intemperance is dis- 
couraged and the revenue not injured. 
Detection of Methylic Alcohol in Presence of Ethylic Alcohol. 
—Three or four methods have been proposed for the detection 
of methylated spirit in various liquids; that open to least ob- 
jection is by J. T. Miller. For the application of the test to 
tinctures and similar spirituous mixtures, some of the spirit is 
first separated by distilling off a drachm or so from about half 
an ounce of the liquid placed in a small flask or test-tube hav- 
ing a long bent tube attached. Into a similar apparatus put 
3U grains of powdered red chromate of potassium, half an 
ounce of water, 25 minims of strong sulphuric acid, and 30 or 
40 minims of the spirit to be tested. Set the mixture aside 
for a quarter of an hour, and then distil nearly half a fluid- 
ounce. Place the distillate in a small dish, add a very slight 
excess of carbonate of sodium, boil down to about a quarter 
of an ounce, add enough acetic acid to impart a distinct but 
feeble acid reaction, pour the liquid into a test-tube, add a 
grain of nitrate of silver dissolved in about 30 drops of water, 
and heat gently for a couple of minutes. If the liquid then 
merely darkens a little, but continues quite translucent, the 
spirit is free from methylic alcohol; but if a copious precipi- 
METHYLIC ALCOHOL, 
Upward of fifty distinct chemical substances have been obtained from 
the solid, liquid, and gaseous products of the destructive distillation 
of coal. 440 
ALCOHOL AND ALLIED BODIES. 
tate of dark-brown or black metallic silver separates, and the 
tube, after being rinsed out and filled with clear water, has a 
distinct film of silver, which appears brown by transmitted 
light (best seen by holding it against white paper), the spirit 
is methylated. 
Explanation.—This test depends for its action on the reducing 
powers of formic acid. In the above operation the ethylic alcohol 
becomes oxidized to acetic acid (the natural acid of the ethyl series), 
which does not reduce silver salts, a minute quantity only of formic 
acid being produced, while the methylic alcohol yields formic acid 
(the natural acid of the methyl series) in a comparatively large 
quantity. Aldehyd, which is also a reducing agent, is simultan- 
eously produced, but removed in the subsequent ebullition with car- 
bonate of sodium. 
Methylated Sweet Spirit of Nitre.—The preparation of spirit 
of nitrous ether from methylated spirit is illegal in Great Britain. 
For the detection of methylic alcohol in this liquid, Mr. Miller 
suggests the following modification of the above process:— 
Shake about an ounce of the sample with 20 or 30 grains of 
anhydrous carbonate of potassium, and, if needful, add fresh 
portions of the salt until it ceases to be dissolved, then pour 
off the supernatant spirit. This serves to neutralize acid and 
to remove water, of which an abnormal quantity may be pres- 
ent. Introduce half a fluidounce of the spirit into a small 
flask; add 150 grains of anhydrous chloride of calcium in 
powder, and stir well together; then, having connected the 
flask with a condenser, place it in a bath of boiling water and 
distil a fluidrachm and a half, or continue the distillation until 
scarcely anything more comes over. The operation is rather 
slow, but needs little attention, and should be done thoroughly. 
The distillate contains nearly the whole of the nitrous ether 
and other interfering substances, while in the retort there re- 
mains a non-volatile compound of chloride of calcium and 
methylic alcohol, if the latter be present. Now add to the 
contents of the flask a fluidrachm of water, which decomposes 
the compound just referred to, and draw over the half drachm 
of spirit required for testing. Add to it the usual oxidizing 
solution composed of 30 grains of red chromate of potassium, 
25 minims of strong sulphuric acid, and half an ounce of wa- 
ter ; let the mixture stand a quarter of an hour, then distil 
half a fluidounce. Treat the distillate with a slight excess of 
cai'bonate of sodium, boil rapidly down to two fluidrachms, 
and drop in, cautiously, enough acetic acid to impart a faint 
acid reaction; pour the liquid into a test-tube about three- 
quarters of an inch in diameter; add two drops of dilated CHLOROFORM. 
441 
acetic acid, and one grain of nitrate of silver in half a drachm 
of pure water; apply heat, and boil gently for two minutes. 
If the spirit is free from methylic alcohol, the solution darkens 
and often assumes transiently a purplish tinge, but continues 
quite translucent, and the test-tube, after being rinsed out and 
tilled with water, appears clean or nearly so. But if the spirit 
contains only 1 per cent, of methylic alcohol, the liquid turns 
first brown, then almost black and opaque, and a film of silver, 
which is brown by transmitted light, is deposited on the tube. 
V) hen the sample is methylated to the extent of 3 or 4 per 
cent., the film is sufficiently thick to form a brilliant mirror. 
To ensure accuracy, the experiments should be performed by 
daylight. 
CHLOROFORM. 
Formula CHC13. 
Process.—Should the necessary appliances be at hand, a 
small quantity of this liquid may easily be prepared by the 
official process. One fluidounce and a half of spirit and 24 of 
water are placed in a retort or flask of at least a quart capacity ; 
8 oz. of chlorinated lime and 4 of slaked lime are added, the 
vessel connected with a condenser, and the mixture heated 
until distillation commences, the source of heat then being 
withdrawn. The condensed liquid should fall into a small flask 
containing water, at the bottom of which about a drachm of 
chloroform will slowly collect. 
Explanation of the Process.—The hypochlorite of calcium believed 
to be present in the chlorinated lime (see the remarks in connec- 
tion with the latter, p. Ill) readily yields up oxygen and chlorine 
to organic substances, the calcium being liberated as hydrate, 
4(Ca2C10) + 411,0 4(Ca2IIO) + 20, + 4C12. The alcohol used 
in making chloroform is thus reduced first to aldehyd:— 
2C2[[(!0 + 02 = 2C2H40 + 211,0 
Alcohol. Oxygen. Aldehyd. Water. 
The action of chlorine on aldehyd then probably gives chloral 
(c7(/or-«/dehyd):— 
C2H40 + 3C12 = C2TIC130 + 3IIC1 
Alrlehyd. Chlorine. Chloral. Hydrochloric acid. 
The hydrochloric acid being at once neutralized by some of the 
liberated hydrate of calcium to form chloride of calcium and water, 
more freed hydrate of calcium and chloral gives formate of calcium 
and chloroform. 
2C,TICL0 + Ca2HO Ca2CIIO, + 2CIICL 
Chloral. 
Hydrate of 
calcium. 
~ — - - & 
Formate of 
calcium. 
: .J 
Chloroform. 442 
ALCOHOL AND ALLIED BODIES. 
Or, neglecting the probable steps in the process, and regarding 
only the materials and the products, 4 molecules of alcohol and 8 
of hypochlorite of calcium give two of chloroform, 3 of formate of 
calcium, 5 of chloride of calcium, and 8 of water, thus:— 
Alcohol. 
40,IIB0 + 8CaCl,02 = 2CHC13 + 3(Ca2C!IIOs) + 5CaCl2 + 811,0 
Hypochlorite 
of calcium. 
Chloroform. 
Formate of 
calcium. 
Chloride of 
calcium. 
Water. 
The hydrate of calcium placed in the generating-vessels is not 
essential, but is useful in preventing secondary decompositions, the 
hydrate of calcium obtainable from the reaction being insufficient 
for this purpose. 
Constitution.—Chloroform is sometimes considered to be the chlo- 
ride of a trivalent radical formyl (CH), the first member of a series 
CnII2,1_1. Glycerin is the hydrate of another member—glyceryl, 
C3II5 (p. 453). 
Chloroform may also be regarded as the chloride of di-chlor- 
methyl; it may be formed from methylic compounds, thus:— 
2011,0 + 2(CaCI2,CaCl202) = 2CIIC13 + CaCL3CaO + 311,0 
Methylic Chlorinated Chloroform. Oxychloride of Water, 
alcohol. lime. calcium. 
Chlorine converts it into tetrachloride of carbon, completing a 
series of substitution products of chloride of methyl. 
cfii|°' 
cl Sic. 
(Cl) 
cjHiJc. 
fen 
C \ Cl V Cl 
(Cl) 
CC14 
or 
Chloride of 
methyl. 
Chloride of 
mono-chlor- 
metliyl. 
Chloride of 
di-chlor- 
metliyl. 
Chloride of 
tri-chlor 
methyl. 
Tetrachlo 
ride of 
carbon. 
or 
The chloride of mono-chlor-methyl, under the name of dichloride 
of methylene, has been used as an anaesthetic. It may be obtained 
by the action of nascent hydrogen on chloroform. 
Chloroform is purified by shaking it with pure sulphuric acid 
containing no trace of nitric acid, which chars and removes hydro- 
carbons, etc., but does not affect chloroform. It is freed from any 
trace of acid by agitation with carbonate of sodium, and from moist- 
ure by distillation with lime. 
Properties.—The sp. gr. of purified chloroform is 1.500. It is 
liable to slowly decompose when exposed to air and light. To ren- 
der it stable a minute amount of alcohol (one-tenth of 1 per cent.— 
0.1, or at most 1 per cent.) is necessary; hence the specific gravity 
of medicinal chloroform is about 1.497 (1.485 to 1.490, Chloroform- 
um Purificatum, U. S. P.). It readily and entirely volatilizes at com- 
mon temperatures, having, to the last drop, its pleasant characteris- 
tic odor. It has a sweetish taste, is limpid, colorless, soluble in 
alcohol (1 to 9 gives Spiritus Chloroformi, U. S. P.) and ether, and 
slightly in water. It burns Avith a sluggish green smoky flame. 
It should be neutral to test-paper, indicating absence of acid ; give 
no precipitate with solution of nitrate of silver, indicating absence 
of ordinary chlorides; remain colorless when heated with potash, 
indicating absence of aldehyd; and give no color to any sulphuric 443 
CHLORAL. 
acid with which it may be shaken, even after the mixture has been 
set aside for half an hour, indicating absence of hydrocarbons, etc. 
Alcohol may be detected by Lieben’s test (p. 429), or by shaking 
with a little of the dye termed “ Hofmann’s violet,” which gives the 
chloroform a purple tint if alcohol be present, but affords no color 
with pure chloroform. 
Commercial Chloroform {Chloroformnm Venale, U. S. P.) should 
have a sp. gr. “ not lower than 1.470 at 15° C.” 
Aqua Chloroforrni, B. P., the official chloroform-water, is made 
by shaking 1 lluidraehm of chloroform with 2d ounces of distilled 
water till dissolved. 
Iodoform (Iodoformum, U. S. P.), analogous in constitution to 
chloroform, the iodine taking the place of the chlorine (CHI3), may 
be prepared by mixing in a retort 2 parts of crystallized carbonate 
of sodium, 1 to 2 parts of iodine, 1 part of alcohol, and 10 of water, 
heating at about 150° F. till colorless, and then pouring into a beaker 
and allowing to settle. The iodoform is deposited in yellow scales, 
which are collected on a filter, washed thoroughly with water, and 
dried between filtering-paper. 
Iodoform appears in the shape of yellow, shining six-sided scales 
with a saffron-like odor ; is volatile at ordinary temperatures, and at 
a temperature above 250° is decomposed, giving off violet vapors. 
Almost insoluble in water, but more so in alcohol, ether, and the 
fixed and volatile oils. Sp. gr. 2.000. 
CHLORAL AND CHLORAL HYDRATE. 
Process.—Pass a rapid stream of dry chlorine into pure ab- 
solute alcohol so long as absorption occurs. During the first 
hour or two the alcohol must be kept cool, afterward gradually 
warmed till ultimately the boiling-point is reached. The prepa- 
ration of a considerable quantity occupies several days. The 
crude produ'et is mixed with three times its volume of oil of 
vitriol and distilled, again mixed with a similar quantity of oil 
of vitriol, and again distilled, and finally rectified from quick- 
lime. 
The formation of chloral would at first sight seem to be due to the 
production from the alcohol (02IIB0) of aldehyd (C21I40), through 
the removal of hydrogen by the chlorine and the substitution of 
chlorine for hydrogen in the aldehyd (C2II40), with formation of 
chlor-aldehyd or chloral ((’2IIC130). But the reactions are far more 
complicated, being somewhat as follows : Aldehyd and hydrochloric 
* acid are first formed ; these with some of the alcohol give monochlo- 
C II ) 
rinated ether, (i2jj5(q j 0, which with more chlorine yields tetra- 
chlorinated ether, j 0, and this in presence of water fur- 
nishes chloral, some alcohol, and some hydrochloric acid (Wurtz 
and Vogt). 
Properties.—The formula of chloral is C2I1C130. It is a colorless 444 
liquid, of oily consistence. Sp. gr. 1.502. Boiling-point 201.2° F. 
Its vapor has a penetrating smell, and is somewhat irritating to the 
eyes. Mixed with water, beat is disengaged, and solid white, crys- 
tallizable hydrous chloral (Chloral, U. S. P.), or, what is more 
generally, though somewhat irregularly, termed chloral hydrate 
(C2HC130,H20) or hydrate of chloral (Chloral Hydras, B. P.), re- 
sults. The latter fuses at 110.8°, and boils at 95° C. or 203° F. It 
sublimes as a white crystalline powder. Both chloral and chloral 
hydrate are soluble in water, alcohol, ether, and oils. Oils and fats 
are also soluble in chloral hydrate. The aqueous solution should 
be neutral, and give no reaction with nitrate of silver. Chloral, 
especially if it contains a trace of acid, may undergo a spontaneous 
change into an opaque, white isomeric modification (metachloral), 
insoluble in water, alcohol, or ether, but convertible by prolonged 
contact with water or by distillation into the ordinary condition. 
By action of weak alkalies chloral first yields formate of the alkali- 
metal and chloroform :— 
ALCOHOL AND ALLIED BODIES. 
Chloral, or rather strong aqueous solution of chloral hydrate (3 in 
4), injected beneath the skin yields nascent chloroform by action of 
the alkali of the blood, and produces narcotic effects (Liebreich, 
Personne). Chloroform itself admits of similar hypodermic use 
(Richardson). If administered by the stomach, 30 to 80 grains of 
solid hydrate arc required. The final products of the reaction of 
the chloroform and blood are formate and chloride of sodium. A 
spirituous solution of potash effects the same transformation. 
CjHCljO + KIIO = KCIIO, + CIIC13. 
CHClj + 4KIIO = KCH02 + 3KC1 + 2II20. 
Solution of ammonia and moist hydrate of calcium, as well as 
weak solutions of fixed alkalies, convert hydrate of chloral into 
formate of the metal and chloroform. The reaction with the slaked 
lime being especially definite and complete (Wood), it may be em- 
ployed in ascertaining the richness of a sample of commercial chloral 
hydrate in chemically pure chloral hydrate. 
2(C2TIC130,II,20) + Ca2IIO = 2CIIC1., + Ca2CII02 + 2II20. 
331 239 
From the foregoing equation and molecular weights it is obvious 
that 100 grains of hydrate of chloral, if quite dry, will yield by 
distillation with 30 grains of slaked lime and an ounce of distilled 
water (in a small flask and long bent tube kept cool by moistened 
paper) 72.2 grains of chloroform by weight or (the sp. gr. of chloro- 
form being taken at 1.497) 47.56 grains by measure, or about 52 
minims. One hundred grains of the official hydrate of chloral 
“ should yield not less than 70 grains of chloroform.” 
Pure Chloral Hydrate.—Liebreich, who first proposed the use of 
chloral hydrate, gives the following as the characteristics of a pure 
article: Colorless, transparent crystals. Does not decompose by the 
action of the atmosphere, does not leave oily spots when pressed be- AMYLIC ALCOHOL. 
445 
tween blotting-paper, affects neither cork nor paper. Smells agree- 
ably aromatic, but a little, pungent when heated. Taste bitter, 
astringent, slightly caustic. Seems to melt on rubbing between the 
fingers. Dissolves in water like candy without first forming oily 
drops, and the solution is neutral or faintly acid to test-paper. Dis- 
solves in bisulphide of carbon, petroleum, ether, water, alcohol, oil 
of turpentine, etc. Its solution in chloroform gives no color when 
shaken with sulphuric acid. Boiling-point 203° to 205° F., and vol- 
atilizes without residue. Distilled with sulphuric acid, the chloral 
should pass over at 205° to 207° F. Melting-point 133° to 136° F., 
again solidifying at about 120° F. Gives no chlorine reaction on 
treating the solution in water (acidulated by nitric acid) with nitrate 
of silver. 
Impure Chloral Hydrate.—Yellowish, cloudy. Decomposes; leaves 
spots by pressing between blotting-paper; decomposes corks and 
paper of the packing. Smells pungent and irritating; on opening 
the bottles sticky and often omits fumes. Taste strongly caustic. 
With water forms oily drops or is partially insoluble. Boils at a 
higher temperature. On treating it with sulphuric acid turns brown, 
with formation of hydrochloric acid. Gives chlorine reaction on 
treating the solution in water (acidulated by nitric acid) with nitrate 
of silver. 
Alcoholates of chloral are obtained on combining alcohols with 
chloral. They are more soluble in chloroform than the hydrate, 
which dissolves to the extent of 1 in 4. 
Bromal (C2IIBr30), hydrate of bromal (C2IIBr30,II20), and alcohol- 
ates of bromal are produced when bromine itstead of chlorine attacks 
alcohol. Iodal (C2EI1.,0) also exists. 
Butyl chloral (C4II5C130), originally but erroneously termed croton 
chloral, is a product of the action of chlorine on aldehyd. Its name 
expresses its constitution; it is chlorinated butyric aldehyd, ordinary 
chloral being chlorinated vinic aldehyd. 
Amylic Alcohol (Alcohol Amylicum, B. P.) (C5IIuIIO, or AyHO) 
is a constant accompaniment of ethylic or common alcohol (C2Il-HO, 
or EtHO) when the latter is prepared from sugar which has been 
derived from starch ; hence the name, from amylum, starch. The 
sugar of potato-starch yields a considerable quantity ; hence the 
alcohol is often called potato oil. It is also termed fousel oil, or 
fusel oil (from <pvu, phuo, to produce), in allusion to the circumstance 
that the supposed oil is not simply educed from a substance already 
containing it, as is usually the case with oils, but is actually pro- 
duced during the operation. It was described as oil, probably be- 
cause it resembled oil in not readily mixing with water; but it is 
soluble to some extent in water, and is a true spirit, homologous 
with spirit of wine. It often contains variable proportions of pro- 
pylic, butylic, and caproylic alcohols. See also Valerianic Acid. 
Amylic alcohol is a “colorless liquid, with a penetrating and op- 
pressive odor, and a burning taste. When pure its specific gravity is 
0.818 ; boiling-point 270° F. Sparingly soluble in water, but soluble 
AMYLIC ALCOHOL. 446 
ALCOHOL AND ALLIED BODIES. 
in all proportions in alcohol, ether, and essential oils. Exposed to 
the air in contact with platinum-black, it is slowly oxidized, yielding 
valerianic acid.” Two allotropic varieties of amylic alcohol exist, 
one dextro-rotating a polarized ray. The amylic alcohol of trade 
probably contains both varieties. 
Acetate of Amyl (C5HuC2H302, or AyA).—To a small 
quantity of amylic alcohol in a test-tube add some acetate of 
potassium and a little sulphuric acid, and warm the mixture; 
the vapor of acetate of amyl is evolved, recognized by its 
odor, which is that of the jargonelle pear. If a condensing- 
tube be attached, the essence may be distilled over, washed by 
agitation with water to free it from alcohol, and separated by 
a pipette. 
KA + Ay HO + H,SOt - Ay A + KHS04 + II.20 
Acetate of 
potassium. 
Amylic 
alcohol. 
Sulphuric 
mid. 
Acetate of 
amyl. 
Acid sulphate 
of potassium. 
Water. 
Fruit-Essences. 
Acetate of amyl, prepared with the proper equivalent proportions 
of constituents as indicated by the above equation, is largely manu- 
factured for use as a flavoring agent by confectioners. Valerianate 
of amyl (C5HuC5II902) is similarly used under the name of apple oil. 
Butyrate of ethyl (C2II5C4II70.2) closely resembles the odor and flavor 
of the pineapple; oenanthylate of ethyl (C2I[5C7II1:j02) recalls green 
gage; pelargonate of ethyl (C2II5C9II1702) quince; suberate of ethyl 
(Et2C8H1204) mulberry; sebacate of ethyl (Et2C10IIlfiO4) melon. 
Hydride of salicyl (C7II502II), or salicylous acid, is the essential oil 
of meadow-sweet (Spircea ulmario), and may be prepared artificially 
by the oxidation of salicin (vide p. 423). Acid salicylate of methyl 
(CII31I( 17II403), or gaulthericacid (Oleum Gaultherice, U. S. P.), forms 
the chief part of the essential oil of the leaves (Gaultheria, U. S. P.) 
of wintergreen (Gaultheria procumbens, the fresh leaves of which 
yield an average of 0.4 per cent, of oil), and may also be prepared 
artificially from salicin. Salicylic acid (C7H6Og or II2C71I403) can 
easily be obtained from the salicylate of methyl, but more cheaply 
from carbolic acid. (Vide p. 451.) 
When heated to about 80° 0. (176° F.) the oil should not yield a 
colorless distillate having the characteristics of chloroform or of 
alcohol. On mixing 5 drops of the oil with 5 drops of nitric acid, 
the mixture should not acquire a deep-red color, and should not 
solidify to a dark-red, resinous mass (abs. of oil of sassafras). 
By mixing ethereal salts with each other and with essential oils in 
various proportions the odor and flavor of nearly every fruit may be 
fairly imitated. (For a set of formulae of fruit-essences, see the 
Pharmaceutical Journal, May 17, 1879.) 
Nitrite op Amyl (Amyl Nitris, U. S. P.) (C5HnN02).—For the 
preparation of this substance Maisch recommends a modification of 
Nitrite of Amyl. AMYLIC ALCOHOL. 
447 
Balard’s process. Amylie alcohol is first rectified until pure; that 
is, until its boiling-point is about 270° F. This alcohol, with about 
an equal bulk of nitric acid, is introduced into a capacious glass 
retort, and a moderate heat is applied and very gradually increased. 
As soon as the mixture approaches boiling the fire is removed, and 
the reaction allowed to continue. If the application of the heat has 
been too rapid or too long continued, considerable frothing occurs 
and the contents of the retort are apt to foam over. With a mod- 
erate and slowly increased heat the reaction is less violent, and the 
temperature rises gradually after the removal of the fire and the 
beginning of boiling. As soon as the thermometer, inserted in the 
tubulure, rises above 212° F., the receiver is changed, the distillate 
now becoming more and more mixed with ethyl-amylie ether and 
nitrate of amyl, readily perceived by the change in odor. 
The distillate obtained below 212° F. is agitated with an aqueous 
solution of hydrate or carbonate of potassium to remove free acids, 
and, after separation, the oily liquid is introduced into a clean retort 
and again slowly heated. The first portion coming over contains 
amylie aldehyd. W hen the very slowly increased heat has risen to 
205° F., the receiver is again changed, and the distillate now col- 
lected as nitrite of amyl, until the thermometer reaches 212° F., 
when the distillation is stopped. 
Nitrite of amyl is a yellowish ethereal liquid; sp. gr. of liquid is 
about 0.873, of vapor 4.03 ; boiling-point 205° F.; soluble in spirit 
of wine, insoluble in water; converted by fused caustic potash into 
valerianate of potassium. Exposed to air, it yields amylie alcohol. 
QUESTIONS AND EXERCISES. 
780. Name the source of methylic alcohol. 
781. What is “ methylated spirit” ? 
782. Describe the method by which methylated spirit is detected 
in a tincture. 
783. In what relation does formic acid stand to methylic alcohol ? 
784. How would you proceed to ascertain whether or not a speci- 
men of sweet spirit of nitre had been made from methylated 
spirit ? 
785. Give details of the production of chloroform from alcohol, 
tracing the various steps by equations. 
786. Is chloroform an ethylic compound ? What is its probable 
constitution ? 
787. How is chloroform purified? 
788. State the character of pure chloroform. 
789. Describe the reactions that occur in the manufacture of chlo- 
ral and chloral hydrate. 
790. What is the nature of the action of alkalies on chloral 
hydrate? 
791. Mention the characters of pure and impure chloral hy- 
drate. 
792. Whence is amylie alcohol obtained? 448 
ALCOHOL AND ALLIED BODIES. 
793. Has valerianic acid any chemical relation to amylic alcohol? 
794. Mention the systematic names of several artificial fruit- 
essences. 
795. What is the formula of nitrite of amyl, and how is it 
prepared ? 
SALTS AND DERIVATIVES OF RADICALS OF OTHER 
SERIES THAN THE CnH2„+1. 
What has been stated regarding radicals having the general for- 
mula C„II2n+1 and their salts may be applied to the radicals of other 
series. 
The series C,JI2n_7 includes phenyl (C6II5), the so-called hydride 
of which (C6H5II, or Phil) is common benzol or benzene (B. P.), a 
colorless volatile liquid distilled from coal-tar, and a body wTiich in 
constitution is the type of a very large class of aromatic organic 
bodies. Toluol (C7IIg), or methyl benzol, is one of the products of 
the distillation of balsam of Peru. The next homologue, xylol 
(C8II10), or dimethyl-benzol, is contained in crude wood-spirit and in 
coal-naphtha: it is a colorless fluid, having an odor faintly resem- 
bling that of benzol; boiling-point 282° F.; sp. gr. .866. 
Benzol is a powerful solvent of grease, and under the name of 
Benzene Colins was introduced by M. Collas in 1848 for cleansing 
stuffs.* By the action of strong nitric acid benzol yields nitroben- 
zol (C6II4(N02)II), a liquid termed, from its odor, artificial oil of 
bitter almonds, or essence of mirbane. Its specific gravity is 1.20 to 
1.29. The odor of this essence, however, is not exactly that of es- 
sential oil of almonds, and its composition is very different, so that 
it is not truly an artificial volatile oil. The natural oil has a sp. gr. 
* The light product of the distillation of petroleum is also, unfor- 
tunately, termed benzine, benzin, benzoline (Benzin, U. 8, P., Petroleum 
Benzin, Petroleum Ether, C5H12, C6IIU, and other hydrocarbons of the 
inarsh-gas series. Boiling-point 50° to GO0 C., 1223 to 140° F.). It 
requires five or six times its bulk of alcohol for solution, while benzol 
dissolves in less than its own bulk. Sp. gr. of benzol, about .9; of ben- 
zin, 0.670 to 0.675. Benzin, Avhen evaporated upon the hand, should 
leave no odor, and when evaporated in a warm dish should leave no 
residue (abs. of heavy hydrocarbons). When boiled a few minutes with 
one-fourth its volume of spirit of ammonia and a few drops of test- 
solution of nitrate of silver, the aminoniacal liquid should not turn 
brown (abs. of pyrogenous products and sulphur compounds). 
The heavier, semi-solid purified product (C16H34, etc.) of the distilla- 
tion of petroleum, melting between 40° C. and 51° C., is officially 
(U. S. P.) termed Petrolatum or Petroleum Ointment. In trade it is known 
as one of the varieties of Vaseline. 
If 5 gm. of Petroleum Ointment be digested, for half an hour, with 
5 gm. of soda and 25 gm. of water, the aqueous layer separated, and 
supersaturated with diluted sulphuric acid, no oily substance should 
separate (abs. of fixed oils or fats of vegetable or animal origin, or of 
resin). Liquefied Petroleum Ointment agitated with sulphuric acid 
of sp. gr. 1.540 should not acquire a dark color within two hours (abs. 
of readily carbonized organic impurities). PHENYL, CARBOLIC ACID, ETC. 
449 
of 1.04 to 1.07, and is a hydride of the negative radical* benzoyl 
(07II501I), a radical derived from the next higher homologue of phe- 
nyl by displacement of hydrogen by oxygen. Nitrobenzol yields 
aniline (vide infra), oil of bitter almonds does not (page 417). On 
this reaction the test for nitrobenzol is founded (p. 451). Dinitro- 
benzol (C6II3(N02)2II) may also be obtained. 
The hydrate of phenyl (C61I5H0), or phenic alcohol or phenol, is the 
phenic acid or carbolic acid (H2C6H40) of commerce (Acidum Carbol- 
icum, U. S. P.), a colorless crystalline substance obtained from coal-tar 
oil by fractional distillation between 180° and 190° C., and subsequent 
purification. A crystalline hydrous acid (H2C6II40,H20) may also be 
obtained. At temperatures above 95° F. ordinary carbolic acid is an 
oily liquid. It is only slightly soluble in water, but readily dis- 
solved by alcohol, ether, and glycerin. In odor, taste, and solu- 
bility (and in appearance when liquefied by heat or by the addition 
of 5 per cent, of water) it resembles creasote, a wood-tar product for 
which carbolic acid has been substituted. Besides hydrate of phe- 
nyl (CglljIIO), coal-tar oil contains cresol, hydrate of cresyl, or cre- 
sylic acid (C7lI7IIO), while wood-tar oil furnishes guaiacol (C7H802) 
—also a product of the destructive distillation of guaiacuin resin— 
and creasol (C8II1002), or creasote. Certain coloring-matters may be 
obtained by the oxidation of carbolic acid; ammonia, or, still better, 
phenyl-ammonia (aniline) mixed with it, and then a small quantity 
of solution of a hypochlorite, gives a blue liquid; a similar effect is 
produced on dipping a chip of deal into carbolic acid (or into 
creasote), then into hydrochloric acid, and afterward exposing it to 
the air. By the following tests carbolic acid may be distinguished 
from creasote: The former boils only at 370° F., while the latter 
readily dries up at 212°. Carbolic acid does not affect a ray of polar- 
ized light; creasote twists it slightly to the right. Carbolic acid is 
either solid or may be solidified by cooling; creasote is not solidified 
by the cold produced by a mixture of hydrochloric acid and sulphate 
of sodium. Creasote from coal (impure or crude carbolic acid) gives 
a jelly when shaken with albumen or with collodion; creasote from 
wood (Creasotum, U. S. P.) is unaffected. Coal-creasote is soluble 
in solution of potash and in the strongest solution of ammonia 
(Read), wood-creasote scarcely soluble. The coal product is soluble 
in 20 volumes of water, and a neutral solution of ferric chloride 
strikes a permanent blue color with the liquid ; wood-creasote is less 
soluble (Aqua Creasoti, U. S. P., is said to contain 1 in 129) and not 
permanently colored blue by ferric chloride. An alcoholic solution of 
the coal oil is colored brown by ferric chloride, a similar solution of 
true creasote green. “ If 1 volume of creasote be mixed with 1 volume 
of glycerin, a nearly clear mixture will result, from which the crea- 
sote will be separated by the addition of 1 or more volumes of water.” 
—U. S. P. Aqueous solution of carbolic acid gives a white precipi- 
tate with bromine-water. 
Carbolic acid is a powerful antiseptic (awl, anti, against, and aij-Ku, 
* Neqative basvlous organic radicals are derived from the ordinary 
or -positive basylous organic radicals by displacement of two atoms of 
hydrogen in the latter radicals by one atom of oxygen. 450 
ALCOHOL AND ALLIED BODIES. 
sepo, I putrefy). In large doses it is poisonous, antidotes being a 
mixture of olive oil and castor oil, freely administered, or a mix- 
ture of slaked lime with about three times its weight of sugar 
rubbed together with a little water. Acidum Carbolicam Crudum, 
U. S. P., is the impure carbolic acid obtained from coal-tar by treat- 
ing it first with an alkali, and then with an acid, and finally distilling. 
It is of a brown shade, and if at first colorless it becomes reddish- 
brown on pressure. It consists of carbolic and cresylic acids in 
variable proportion, together with impurities derived from coal-tar: 
950 measures of warm water on being agitated with 50 measures of 
the liquid will dissolve out the two acids, and should not leave more 
than 5 measures of impurity (10 per cent.). Carbolic acid is soluble 
in oil of vitriol, sulphocarbolic acid (IIC6If5S04) or sulphophenic acid 
being formed. On diluting and mixing with oxides, hydrates, or 
carbonates, sulphocarbolates are formed. The formula of svtphocar- 
bolate of sodium (Sodii Sulphocarbolas, U. S. P.) is NaC6H6S04,2II20; 
sulphocarbolate of zinc, Zn(C6H5S04)2H20. Trinitro-carbolic acid 
(C6H3(N02)30) is formed on slowly dropping carbolic acid into fuming 
nitric acid; it is the yellow dye known as carbazotic acid or picric 
acid; most of the picrates are explosive by percussion. Both car- 
bolic acid and benzol are secondary products obtained in the manu- 
facture of coal-gas; hence, indeed, the word phenic, and thence 
pherrf (from tpaivu, phaino, I light, in allusion to the use of coal-gas). 
Carbolic acid (Cr>II5110) may be regarded as benzol in which one 
atom of hydrogen (ll) is displaced by hydroxyl (HO). When two 
atoms of hydrogen in benzol are displaced by two of hydroxyl, 
resorcin (C6II421IO) results, a colorless, crystalline antiseptic having 
many advantages over carbolic acid in surgical operations. Its name 
was given in allusion to its original source, resin, and to certain sim- 
ilarities with orcin. It occurs in fiat prisms readily soluble in most 
liquids. It may be made by passing benzol vapor into hot sulphuric 
acid and heating the product (benzol-disulphonic acid, C6H4(S02,H0)2) 
with excess of soda. 
Benzol-disulphonate 
of sodium. 
C6H4(S02.Na0)2 + 2NaII0 = CBII4(TIO)2 + ‘2Na2S03 
Soda. 
Itesorcin. 
Sulphite of 
sodium. 
Resorcin is one of a group of three metameric dihydroxyl-benzols 
(CfiII42IIO). Their chemical relationships warrant the conclusion 
(on the atomic theory) that the cause of their differences in proper- 
ties is a difference of position of the two atoms of hydroxyl in the 
molecule, these being, respectively, next to each other, separated by 
one atom (of CII) and by two atoms of CII), thus:— 
CYIIO) 
iie c(iio) 
I ll 
Va 
Olio) 
lie (ii 
I II 
HCW’(HO) 
C(IIO) 
A 
lie cn 
I II 
lie eH 
e(iio) 
Ortho-dihydroxyl benzol 
(pyroeatechin). 
Meta-dihydroxyl-benzol 
(resorcin). 
Para-diliydroxyl-benzol 
(liydroquinone). SALICYLIC ACID. 
451 
Aniline, or phenylamine, is a product of the action of nascent hy- 
drogen on nitrobenzol. 
(C6H5 
C6H5N02 + 3II2 = N II + 2II20, 
Nitrobenzol. Hydrogen. | JJ 
the substance whence, by oxidation, etc. aniline-red (magenta), 
-orange, -yellow, -green, -blue, -violet (mauve), and -black are pro- 
duced. The process with zinc-dust (vide Watt’s Diet.) answers 
fairly well: 1 oz. of nitrobenzol gives a drachm or two of aniline. 
But action of iron filings and acetic acid on an alcohol solution an- 
swers better, 3 oz. of nitrobenzol giving 1 oz. of aniline. To detect 
nitrobenzol add alcohol and hydrochloric acid and a little zinc; 
when action has ceased, liberate aniline by shaking with excess of 
potash; dissolve out the aniline by agitation with ether • to the 
decanted ethereal liquid add solution of chlorinated lime; a violet 
color or tint results. 
Salicylic Acid (H2C7II403) (Acidum Salicylicum, U. S. P.).—The 
natural acid salicylate of methyl is described on page 446. Salicylic 
acid itself occurs in several species of violet (Maudelin), especially 
in Pansy (Viola Tricolor, U. S. P.). Artificial salicylic acid is made 
as follows: Carbolic acid (II2C6II40), by acquiring the elements of 
carbonic acid gas (C02), is converted into salicylic acid (Kolbe). 
The carbolic acid is first mixed with caustic soda in molecular 
proportions and dried. The resulting acid carbolate of sodium 
(NaIIC6H40), made hot, is saturated with carbonic gas, every pair 
of molecules of the carbolate then affording one of regenerated car- 
bolic acid, which distils off, and one of normal carbolate of sodium 
which, absorbing the gas, becomes normal salicylate of 
sodium (Na2C7FI403). The latter, by action of hydrochloric acid, 
furnishes salicylic acid, which may be purified by crystallization 
from ethylic or amylic alcohol or ether. Salicylic acid, like car- 
bolic acid, is a powerful antiseptic, but is free from the taste and 
smell of carbolic acid. It is only slightly soluble in water, but 
readily soluble in aqueous solutions of such alkali-metal salts as 
borax, phosphate of sodium, or citrate of potassium. A similar 
antiseptic, cresotic acid (C8H803), is similarly obtained from cre- 
sylic acid (C7II80). Ferric chloride strikes a violet coloration with 
both salicylic and cresotic acids. Both acids have antipyretic 
powers. The true salicylates of the alkali-metals, and probably, 
therefore, the cresotates, are very feeble antiseptics. Salicylate of 
sodium (Sodii Salicylas, U. S. P.), 2NaC7II503,II20, is fairly soluble 
in water. Carbolic acid often containing acid, commercial 
salicylic acid may often contain cresotic acid. Salicylic acid is sol- 
uble in strong sulphuric acid, yielding colorless sulphosalicylic acid 
(1IC7II502S04). Salicylic acid yields colored substances on being 
nitrated and etherified, etc. If it affords a reddish or brownish tint 
when its aqueous solution is shaken with chlorate of potassium and 
hydrochloric acid, and, afterward, ammonia, carbolic acid is present. 
Aloins.—The aloes {Aloe, U. S. P.) of pharmacy (from Aloe Soco- 
trina) is an evaporated juice, doubtless much altered by the tem- 452 
ALCOHOL AND ALLIED BODIES. 
perature to which it is subjected. Aloe Purificata, U. S. P., is the 
evaporated alcoholic extract. 
Barbaloin.—This substance, first obtained by T. and II. Smith, 
occurs in minute crystals in Barbadoes aloes. It is readily procured 
by making a decoction in water acidified with a little hydrochloric 
acid, after some hours pouring off the precipitated resin, and evapor- 
ating the liquid to a syrup. The aloin crystallizes out in a day or 
two. Barbaloin yields by the action of bromine and chlorine sub- 
stitution compounds. Nitric acid dropped upon it produces a red 
color which soon fades. Boiled for some time with strong nitric 
acid, barbaloin gives, together with oxalic and picric acids, a yellow 
substance, chrysammic acid, which furnishes beautiful red salts (Til- 
den). Anthracene (C14II10) has been obtained by deoxidation of 
barbaloin. 
Nataloin.—This body was discovered by Fliickiger in Natal aloes. 
It crystallizes readily in rectangular plates, either from spirit or from 
water. No bromine or chlorine substitution derivatives have yet been 
formed, but an acetyl oompound has been analyzed (Tilden). Nata- 
loin moistened with nitric acid gives a red coloration which does not 
fade. When boiled with nitric acid it yields no chrysammic acid, 
but only oxalic and picric acids. 
Socaloin, or Zanaloin.—Histed and Fliickiger have shown that 
Socotrine or Zanzibar aloes yields an aloin distinct from those just 
described. It forms tufted acicular prisms. Nitric acid scarcely 
alters the color of socaloin. Neither socaloin nor barbaloin affords 
any color when vapor from a glass rod moistened with nitric acid 
is brought near to a drop of oil of vitriol containing a minute frag- 
ment of the aloin, while nataloin gives rise to a blue coloration. 
Analysis.—To Aloin, or powdered aloes, on a white plate, add 
strong nitric acid. No color = Socaloin; crimson color = Nataloin 
or Barbaloin. To another portion add strong sulphuric acid and 
vapor of nitric acid. A blue color — Nataloin •, no blue color — Barb- 
aloin. 
Formulae.—The reactions of these bodies seem to indicate that 
they are complex phenols. Phenol being the phenyl hydrate, 
CfiII5IIO, and cresol being methyl-phenol, CBII4CII31I0, the aloins 
may possibly have a similar constitution 5 that is, they may be the 
hydrates of radicals in which part of the hydrogen is replaced by 
groups of atoms. Since Tilden made this suggestion, E. von Som- 
maruga and Egger (Pharmacographia) have arrived at the conclu- 
sion that the aloins form an homologous series, and that they have 
the composition indicated in the following formulas :— 
Socaloin C15II1607 
Nataloin 
Barbaloin C17H20O7 
Tilden’s more recent experiments indicate, however, that barbaloin 
(C17II20O7) and socaloin (C15H1607) are isomeric in the anhydrous 
state, but that socaloin and its derivatives in the hydrous condition 
contain more water of crystallization than barbaloin. Nataloin 
(C16H1807) seems to be isomeric with the others, but is less soluble, A LOINS, 
453 
and does not yield either chrysammic acid or chloro- or bromo-deriva- 
tives (C161I15C1307 ; C16H15Br307). The acetyl derivative appears to 
have the formula C16H15(C21130)30T. 
In the series we have the univalent radical allyl (C3H5), 
whose sulphide ((C3II5)2S) is essential oil of garlic (Allium, U. S. P.), 
and sulphocyanate (C3lI5CyS), the chief part of the essential oil of 
mustard, the body to which mustard owes its power of inducing in- 
flammatory action on the skin (“ Mustard Poultice ” and Charta 
Sinapis, U. S. P.). Mustard (Sinapis, U. S. P.) is a powdered mix- 
ture of black, or rather reddish-brown, and white mustard-seeds. The 
white mustard-seed contains sinalbin (C30H44N2S2OJ6), a glucoside 
which, in contact with the myrosin in an aqueous extract of mustard, 
yields the sulphocyanide of a peculiar radical acrinyl, a body which 
forms part of the essential oil of mustard-paste. 
C3oH44N,S2016 = c7ii7ocns + cmiimo5nshso4 + CfiII]206 
The black contains the albumcnoid ferment myrosin, resembling the 
emulsin of almonds (p. 416), and myronate of potassium or sinigrin. 
The latter is the body which, under the influence of the former, 
yields the chief part of the pungent oil of mustard-paste. 
Sinalbiu. 
Sulphocyanate 
of acrinyl. 
Acid sulphate 
of sinapiue. 
Glucose. 
KC10H19NS2O10 - KHS04 + CsH5CNS + C6Hla06 
Myronate of 
potassium. 
Acid sulphate 
of potassium. 
Oil of 
mustard. 
Glucose. 
Crude oil of mustard often contains cyanide of allyl, C3TI5CN. 
In the Pharmacopoeia of India the seed of Sinapis juncea Iiai, or 
Indian Mustard-riant, is official in addition to that of S. alba and 
S. nigra. It is the common mustard of warm countries. It does 
not differ chemically from other mustard. Allyl compounds are also 
met with in several other cruciferous and liliaceous plants. 
In the C„H2n series occurs ethylene or olefiant gas (C2II4), the 
chief illuminating constituent of coal-gas (made by heating spirit of 
wine with twice its volume of strong sulphuric acid), a bivalent 
radical, the alcohol of which is glycol (C2II42IIO). Etherol, or Ethe- 
real Oil (Oleum JEthereum, U. S. P.), a mixture of equal volumes of 
ether and of heavy oil ofi wine (C]51I30?), a hydrocarbon polymeric 
with olefiant gas, is one of the products of the action of excess of 
sulphuric acid on alcohol; its sp. gr. is 0.917. In CnII2n_1/// series 
the trivalent hypothetical radical glyceryl (C3II5) is found, the hydrate 
of which (C3H53IIO) is glycerin. The homologues of glycol (e. g., 
propylene glycol and butylene glycol) are termed glycols, the homo- 
logues of glycerin glycerins. By oxidation of glycols, acids of the 
lactic series are formed (glycolic, lactic, and oxybutyric acids), just 
as by oxidation of ordinary alcohols acids of the acetic series are 
formed. It will be noticed that the chemical composition of the 
radicals glyceryl and allyl is identical (C,H,), but the former is 
trivalent and the latter univalent; hence they probably differ in 
physical constitution; they are isomeric, possibly polymeric with 
each other. From a glyceryl compound (glycerin), however, an 
allyl salt (iodide) can be produced. By distilling a mixture of 454 
ALCOHOL AND ALLIED BODIES. 
glycerin and biniodide of phosphorus, iodide of allyl (C3II5I) is 
obtained, and on digesting this with sulphocyanate of potassium the 
sulphocyanate of allyl, or artificial oil of mustard, results ; identical 
with the chief constituent of the natural oil. 
Glycerin.—Glycerin, or Glyceric Alcohol (C;,H53HO), is 
the hydrate of the basylous radical of most oils and fats, 
bodies which are mainly oleates, palmitates, and stearates of 
glyceryl (g'lyeyl or propenyl). When these substances are 
heated with metallic hydrates (even with water—hydrate of 
hydrogen—at a temperature of 500° F. or 600° F.), double 
decomposition occurs, oleate, palmitate, or stearate of the metal 
is formed, and hydrate of glyceryl, or glycerin. Hence gly- 
cerin is a by-product in the manufacture of soap, hard can- 
dles, and lead-plaster (vide Index). 
Properties.—Glycerin is viscid when pure; specific gravity 1.28 
(not below 1.25 U. S. P. = 95 per cent.) ; has a sweet taste; is soluble 
in water or alcohol in all proportions. It has remarkable powers as 
a solvent, is a valuable antiseptic even when diluted with 10 parts 
of water, and useful as an emollient. In vacuo it may be distilled 
unchanged, but under ordinary atmospheric pressure it is decom- 
posed by heat. From damp air glycerin absorbs moisture slowly, 
but in considerable proportions. Perfectly pure and anhydrous 
glycerin, at a few degrees below the freezing-point of water, some- 
times solidifies to a mass of crystals. It may be extracted from 
many substances insoluble in absolute alcohol by digestion in the 
latter, acids being first neutralized by oxides and oxides and hydrates 
by acids. 
“ Glycerin should be neutral to litmus-paper. Upon warming a 
portion of 5 or 6 gin. with half its weight of diluted sulphuric acid, 
no butyric or other acidulous odor should be developed. A portion 
of 2 or 3 gm., gently warmed with an equal volume of sulphuric 
acid in a test-tube, should not become dark colored (abs. of cane- 
sugar). A portion of about 2 gm., heated in a small, open porcelain 
or platinum capsule upon a sand-bath until it boils, and then ignited, 
should burn and vaporize so as to leave not more than a dark stain 
(abs. of sugars and dextrin, which leave a porous coal). A portion 
heated to about 85° C. (185° F.) with test-solution of potassio-cupric 
tartrate should not give a decided yellowish-brown precipitate, and 
the same result should be obtained if, before applying this test, an- 
other portion be boiled with a little diluted hydrochloric acid for 
half an hour (abs. of sugars). After full combustion no residue 
should be left (metallic salts). Diluted with 10 times its volume of 
distilled water, portions should give no precipitates or colors when 
treated with test-solution of nitrate of silver, chloride of barium, 
chloride of calcium, sulphide of ammonium, or oxalate of ammonium 
(acrylic or hydrochloric, sulphuric, oxalic acid, iron, or calcium 
salts).”—U. 8. P. 
Tests.—Heat one or two drops of glycerin in a test-tube, or ALBUMENOTD SUBSTANCES. 
455 
with strong sulphuric acid, acid sulphate of potassium, or other 
salt powerfully absorbent of water; vapors of acrolein (from 
acer, sharp, and oleum, oil) are evolved, recognized by their 
powerfully irritating effects on the eyes and respiratory pas- 
sages. If the glycerin be in solution, it must be evaporated 
as low as possible before, applying this test.—Add a few drops 
of the fluid suspected to contain glycerin to a little powdered 
borax; stir well together; dip the looped end of a platinum 
wire into the mixture and expose to an air-gas flame: a deep 
green color is produced (Senier and Lowe). 
The glycerin liberates boracic acid, and it is the latter which colors 
the flame. Ammoniacal salts, which similarly affect borax, must 
first be got rid of by boiling with solution of carbonate of sodium. 
Liquids containing much indefinite organic matter must sometimes 
be evaporated to dryness, the residue extracted by alcohol, and the 
latter tested for the glycerin. To detect traces liquids must be con- 
centrated. 
Besides glycerin itself (Glycerinum, U. S. P.), solutions or mix- 
tures of starch and of yolk of egg and glycerin (Glyceritum Amyli, 
U. 8. P.; Glyceritum Vitelli, or Glyconin, U. S. P.) are official. 
796. Give the formulae of some compounds of radicals which have 
the general formula CnII2n_/, C„H2n~/, Cnll2„_1///, and CnH2n//,— 
e. g. benzol, essential oil of mustard, glycerin, and glycol. 
797. State the difference in composition of natural and artificial 
oil of bitter almonds. 
798. How is the so-called artificial oil of bitter almonds prepared? 
799. What are the uses, composition, source, and properties of 
Carbolic Acid? 
800. State the characters by which carbolic acid is distinguished 
from Creosote. 
801. In what relation does carbolic acid stand to cresylic acid? 
802. What is the general formula of sulphocarbolates ? 
803. Draw out an equation explanatory of the production of 
aniline. 
804. Mention the chief properties of Glycerin. 
805. What is the specific gravity of glycerin ? 
806. By what test is glycerin recognized ? 
807. Enumerate some official preparations in which glycerin is 
employed as a solvent. 
QUESTIONS AND EXERCISES. 
Albumen.—Agitate thorouglily white of egg (Albumen On, 
B. P.) witli water, and strain or pour oft’ the liquid from the 
ALBUMENOID SUBSTANCES. 456 
ALBUMENOIDj SUBSTANCES. 
flocculcnt membranous insoluble matter. One white to 100 c.c. 
of water forms the “ Test-Solution of Albumen,” U. S. P. 
Test.—Heat a portion of this solution of albumen to the 
boiling-point; the albumen becomes insoluble, separating in 
clots or coagula of characteristic appearance. 
Other Reactions.—Add to small quantities of aqueous solu- 
tion of albumen solutions of corrosive sublimate, nitrate of 
silver, sulphate of copper, acetate of lead, alum, perchloride of 
tin ; the various salts not only coagulate, but form insoluble 
compounds with albumen. Hence the value of an egg as a 
temporary antidote in cases of poisoning by many metallic 
salts, its administration retarding the absorption of the poi- 
son until the stomach-pump or other measures can be applied. 
Sulphuric, nitric, and hydrochloric acids precipitate albumen ; 
the coagulum is slowly redissolved by aid of heat, a brown, 
yellow, or purplish-red color being produced. Neither acetic, 
tartaric, nor organic acids generally, except gallo-tannic, coag- 
ulate albumen. Alkalies prevent the precipitation of albumen. 
Yolk or Yelk of Egg ( Vitellus, U. S. P.) contains only 3 per cent, 
of albumen, the white 12£. The yolk also contains only 30 per cent, 
of yellow fat and 14 of casein. 
Albumen is met with in large quantities in the serum of blood, in 
smaller quantity in chyle and lymph, and in the brain, kidneys, 
liver, muscles, and pancreas. It is not a normal constituent of 
saliva, gastric juice, bile, or mucus, but occurs in those secretions 
during inflammation. It is found in the urine and faeces only under 
certain diseased states of the system. 
The cause of the coagulation of albumen by heat has not yet been 
discovered. 
Albumen has never been obtained sufficiently pure to admit of its 
composition being expressed by a trustworthy formula; Gerhardt 
regarded it as a sodium compound (IINaC72II]10N18SO22,II2O). 
Egg-albumen (and, to some extent, blood-albumen) is largely used 
by calico-printers as a vehicle for colors, serving also, when dry, as 
a glaze. Curriers prize egg oil for softening leather. 
Albumen coagulated by heat is said to be recoverable in a scarcely 
altered fluid condition by contact with a dilute aqueous solution of 
a very small proportion of pepsin. 
Fibrin is the chief constituent of the muscular tissue of animals. 
It occurs in solution in the blood, and its spontaneous solidification 
or coagulation is the cause of the clotting of blood shortly after being 
drawn from the body—a phenomenon which cannot at present be 
explained satisfactorily. Fibrin may be obtained by whipping fresh 
blood with a bundle of twigs, separating the adherent fibres, and 
washing in water till colorless. It may be dried or kept under spirit 
of wine. 
Fibrin, Casein, Legumin. CASEIN. 
457 
Average Composition of Blood {in 1000 Parts). 
(Compiled by Kirkes). 
Water 784 
Albumen 70 
Fibrin 2.2 
Red corpuscles (dried) 130 
' Cholesterin 0.08 
Cerebrin ...... 0.40 
Serolin ...... 0.02 
Oleic and margaric acids . 
Volatile and odorous fatty acid 
Fat containing phosphorus 
Fatty 
matters. 
1.4 
> Chloride of sodium ...... 3.6 
Chloride of potassium .35 
Phosphate of sodium (Na3P04) ... .2 
Carbonate of sodium ..... .82 
Sulphate of sodium .28 
Phosphates of calcium and magnesium . . .25 
Oxide and phosphate of iron .... .50 
Inorganic 
salts. 
Extractive matters, biliary coloring-matter, gases, 
and accidental substances .... 6.4 
1000.00 
Percentage proportion of the chief constituents of Blood. 
Water 78.4 
Red corpuscles (solid residue) . . . 13.0 
Albumen of serum ..... 7.0 
Inorganic salts ...... .603 
Extractive, fatty, and other matters . . .777 
Fibrin _ .22 
100.000 
Casein occurs in Cow’s Milk {Lae, B. P.) to the extent of 3 per 
cent, dissolved by a trace of alkaline salt. Its solution does not 
spontaneously coagulate like that of fibrin, nor by heat like albumen ; 
but acids cause its precipitation from milk in the form of a curd 
(cheese) containing the fat- (butter)-globules previously suspended in 
the milk, a clear yellow liquid (or w'hey) remaining. Curds and 
whey are also produced on adding to milk a piece or an infusion of 
rennet, the salted and dried inner membrane of the fourth stomach 
of the calf. The exact action of rennet is not known. Respecting 
rennet, Soxhlet says : “ 60 to 80 grains of calf’s stomach, steeped for 
five days in 1 litre of a 5-per cent, solution of common salt at ordi- 
nary temperatures, yield a solution of which 1 vol. will coagulate 
10,000 vols. of new milk at a temperature of 95° F. in forty minutes. 
If the filtered solution is treated with 60 to 90 grains more of stomach, 
a solution of double strength is obtained ; another repetition gives a 
solution three times the strength of the original one. To prevent 
decomposition, about 0.3 per cent, of thymol may be added to the 
concentrated rennet extract solution. Possibly a slight taste due to 458 
ALBUMENOID SUBSTANCES. 
this may be detected in the finest cheese, but for the same reason oil 
of cloves is much more objectionable. Boracic acid is on all accounts 
the best antiseptic to employ, and solutions to which it has been added 
may be kept in covered vessels for months. All extract-solutions 
lose strength on keeping; during the first two months the solution 
may become 30 per cent, weaker, then the strength remains nearly 
constant for eight months in the case of a solution of 1 in 18,000. 
A lcohol is almost as good an antiseptic as boracic acid if the solution 
be preserved in well-stoppered flasks.” 
Average Composition of 1000 Parts of Milk. 
Specific 
gravity. 
Water. 
Solid 
constit- 
uents. 
Casein 
and ex- 
tractive. 
Sugar. 
Butter. 
Salts. 
Woman . . 
f 1.030- \ 
11.034 / 
870 
130 
37 
50 
40 
3 
Cow .... 
< 1.030- \ 
11.035 / 
877 
123 
40 
46 
30 
7 
Specific gravity alone, as taken by the form of hj-drometer termed 
a lactometer, or even by more delicate means, is of little value as an 
indication of the richness of milk, the butter and the other solids 
exerting an influence in opposite directions. Good cow's milk affords 
from 10 to 12 per cent, by volume of cream and 3 to 3| per cent, of 
butter. The water of milk seldom varies more than from 87 to 88 
per cent., and the solid constituents from 13 to 12. Indeed, excluding 
its butter, the milk of healthy cows is curiously regular in composi- 
tion. The non-fatty solids in the mixed milk of a herd or dairy of 
healthy cows is almost a constant quantity—namely, 9.3 per cent. 
A lower proportion of non-fatty solids in a sample of milk points to 
the addition of water. Thus, supposing that 100 grains of a speci- 
men of milk evaporated to dryness, and all butter extracted from the 
residue by ether, yielded a non-fatty residue of 7.44 grains, the 
specimen would probably be four-fifths milk and one-fifth water. 
For if 9.3 indicate 100, then 7.44 indicate 80. Occasionally, under 
exceptional circumstances, a sample of genuine milk might be slightly 
poorer than that from a healthy herd, and therefore in England, for 
legal purposes, a standard of 9 per cent, by weight of non-fatty 
solids and 2.5 per cent, of butter-fat has been proposed. Only in 
the rare cases of milk containing an unusually large proportion of 
butter-fat would any milk yielding less than 9 per cent, of non-fatty 
solids be regarded as genuine. And, again, no milk would be con- 
sidered genuine, under this standard, if it yielded less than 2.5 per 
cent, of fat, not even in the rare case of its containing an unusually 
large proportion of real non-fatty milk-solids. Half-starved cows 
might yield milk below these standards, but it could scarcely be 
considered to be genuine or better fitted for food than milk watered 
after leaving the cow. If, however, such milk is to be regarded as 
genuine, a standard of 8.5 of non-fatty solids will not be too low. 
Under the microscope milk is seen to consist of minute corpuscles GELATIGENOUS SUBSTANCES. 
459 
floating in a transparent medium. These corpuscles consist of fatty 
matter (butter), said to be contained in a filmy albumenoid envelope. 
The fat is fluid at the normal temperature of the animal, and remains 
so until the milk is well agitated by churning or otherw ise, or until 
the milk is frozen. 
Legumin, or vegetable casein, is found in most leguminous seeds, 
such as sweet and bitter almonds. Peas contain about 25 per cent, 
of legumin. 
Vegetable albumen is contained in many plant-juices, and is depos- 
ited in floceuli on heating such liquids. Vegetable fibrin is the name 
given by Liebig and Dumas to the portion of the gluten of wheat 
which is insoluble in alcohol and ether (vide p. 401). 
Albumenoid substances are nearly identical in percentage compo- 
sition. Albumen (and fibrin) contains 53.5 of carbon, 7 of hydrogen, 
15.5 of nitrogen, 22 of oxygen, 1.6 of sulphur, and .4 of phosphorus. 
Casein contains no phosphorus. These three bodies are often termed 
the plastic elements of nutrition, under the assumption that animals 
directly assimilate them in forming muscles, nerves, and other tis- 
sues—starch, sugar, and similar matter forming the respiratory 
materials of food, because more immediately concerned in keeping 
up the temperature of the body by the combustion going on between 
them and their products and the oxygen of the air in the blood. 
The whole of the organic nitrogen in food must not, however, be 
regarded as representing true albumenoids, some existing as amidic 
and similar compounds—bodies having a simplicity of composition 
characteristic of the products of physiological action on food, rather 
than that complexity of composition characteristic of true nutrients. 
Albumenoids in decomposing yield much fatty as well as other sub- 
stances. Possibly, a portion, at least, of the aclipocire (adeps, fat; 
cent, wax), or corpse-fat, characteristic of the remains of buried 
animals, is thus derived. 
Musk (Moschus, U. S. P.), “ the dried secretion from the preputial 
follicles of Moschus moschiferus ” (the Musk Deer), is a mixture of 
albumenoid, fatty, and other animal matters with a volatile odorous 
substance of unknown composition. 
GELATIGENOUS SUBSTANCES. 
These nitrogenous bodies differ chemically from the albumenoid 
in containing less carbon and sulphur and more nitrogen. They 
are contained in certain animal tissues, and on boiling with water 
yield a solution which has the remarkable property of solidifying 
to a jelly on cooling. The tendons, ligaments, bones, skin, and 
serous membranes afford gelatin proper; the cartilages give chon- 
drin, wdiich differs from gelatin in composition and in being pre- 
cipitated by vegetable acids, alum, and the acetates of lead. The 
purest variety of gelatin is isinglass, B. P. (Ichthyocolla, U. S. P.), 
the swimming-bladder or sound of various species of Acipenser, 
Linn., prepared and cut in fine shreds. Small quantities are more 
easily disintegrated by a file than a knife. Fifty grains dissolved in 460 
PEPSIN. 
5 ounces of distilled water forms the official 11 Solution of Gelatin,” 
B. P. Glue is an impure variety of gelatin, made from the trim- 
mings of hides; size is glue of inferior tenacity, prepared from the 
parings of parchment and thin skins. “ Among the varieties of 
gelatin derived from different tissues and from the same sources at 
different ages, much diversity exists as to the firmness and other 
characters of the solid formed on the cooling of the solutions. The 
differences between isinglass, size, and glue in these respects are 
familiarly known, and afford good examples of the varieties called 
weak and strong, or low and high, gelatin. The differences are 
sometimes ascribed to the quantities of water combined in each case 
with the pure or anhydrous gelatin, part of which Avater seems to 
be intimately united with the gelatin; for no artificial addition of 
water to glue would give it the character of size, nor Avould any 
abstraction of water from isinglass or size convert it into the hard, 
dry substance of glue. But such a change is effected in the gradual 
process of nutrition of the tissues ; for, as a general rule, the tissues 
of an old animal yield a much firmer or stronger jelly than the 
corresponding parts of a young animal of the same species” 
(Kirkes’s Physiology). 
Gelatin appears to unite chemically with a portion of the Avater in 
which it is soaked when used for culinary and manufacturing pur- 
poses, for a solution of glue in a hot anhydrous glycerin does not 
yield an ordinary jelly on cooling. From its solution in Avater 
gelatin is precipitated by alcohol, corrosive sublimate, perchloride 
of platinum, and by tannic acid. Its aqueous solution is not, like 
that of albumen, coagulated by heat. By prolonged ebullition its 
gelatinizing power is destroyed. 
Pepsin (from irt-ru, peptu, I digest) is a nitrogenous substance 
existing in the gastric juice and as a viscid matter in the peptic 
glands and on the walls of the stomach of animals. To isolate it, 
the mucous membrane of the stomach (of the hog, sheep, or calf, 
killed fasting) is scraped, and macerated in cold water for twelve 
hours; the pepsin in the strained liquid is then precipitated by 
acetate of lead, the deposit washed once or twice by decantation, 
sulphuretted hydrogen passed through the mixture of the deposit 
with a little water to remove the whole of the lead, and the filtered 
liquid evaporated to dryness at a temperature not exceeding 105° F. 
Pepsin is a powerful promoter of digestion ; its solution is hence 
frequently termed artificial gastric juice. As met Avith in pharmacy 
its strength varies greatly. It is often prepared by simply mixing 
with starch the thick liquid obtained on macerating the scraped 
stomach Avith water, and evaporating to dryness. (Vide Pharma- 
ceutical Journal, 1865-66, p. 112, and 1871-72, pp. 785 and 843.) 
The English official process (Pepsin, B. P.) simply consists in scrap- 
ing the viscid pulp from the slightly washed inner surface of the 
stomach, and quickly evaporating it to dryness on glass or glazed 
PEPSIN. PANCREATIN, 
earthenware at a temperature not exceeding 100° F. The product 
is powdered. “ A light yellowish-brown powrder, having a faint, 
but not disagreeable odor, and a slightly saline taste, without any 
indication of putrescence. Very little soluble in water or spirit. 
Two grains of it with an ounce of distilled water, to which five 
minims of hydrochloric acid have been added, form a mixture in 
which 100 grains of hard-boiled w'hite of egg, in thin shavings (or, 
better, in pulp formed by passing it through copper wire gauze con- 
taining thirty-six meshes to the inch), will dissolve on their being 
digested together for about four hours at a temperature of 98° F. (or, 
better, 130° F.). The solvent or digestive action of pepsin on the 
albumenoids, etc. in the stomach results in a fluid termed peptone. 
It is thus that such food is prepared for conversion into blood. 
Artificial peptone is made by digesting blood-fibrin writh pepsin in 
very weak hydrochloric acid. Peptone is not readily coagulated by 
heat, and it freely diffuses through membranes. It appears to be 
isomeric with albumen. Some vegetables, notably the leaves of the 
papaw tree, Carica papaya, appear to contain a principle, “papaine,” 
analogous in properties to pepsin. According to Wurtz, papaine is 
an albumenoid. 
(For a r6$um6 of the different modes of preparing pepsin, see an 
article by Petit in the Pharmaceutical Journal for July 17, 1880.) 
The preparation official in the United States is Pepsinum Saccha- 
ratum: “ 1 part of Saccharated Pepsin, dissolved in 500 parts of 
water acidulated with 7.5 parts of hydrochloric acid, should digest 
at least 50 parts of hard-boiled egg-albumen in five or six hours at a 
temperature of 38° to 40° C. (100° to 104° F.).” 
Liquor Pepsini, U. S. P., is a mixture of 40 parts of saccharated 
pepsin, 12 of hydrochloric acid, 400 of glycerin, and water to make 
1000. It should not develop an ammoniacal odor on keeping (abs. 
of mucus). 
PANCREATIN. 
The pancreas (or “ sweetbread ,:) secretes a colorless fluid which 
contains 1J to 2J per cent, of an albumenoid substance which has 
the power of converting starch into sugar, and, especially, of emul- 
sifying fat. It may be precipitated by chloride of sodium from an 
acidulated infusion of the pancreas. It is soluble in cold water. 
An extremely small proportion emulsifies a large volume of fat. 
QUESTIONS AND EXERCISES. 
808. In what form is albumen familiar ? 
809. Name the chief test for albumen. 
810. Why is the administration of albumen useful in cases of 
poisoning? 
811. Mention the points of difference between yolk and white of 
egg. 
812. From what source other than egg may albumen be obtained? 
813. In what respect does fibrin differ from albumen? 462 
FATTY BODIES. 
814. Enumerate the chief constituents of blood? 
815. How may fibrin be obtained from blood? 
816. State the difference between casein, fibrin, and albumen. 
817. What are the relations of cream, butter, curds and whey, and 
cheese, to milk? 
818. Describe the microscopic appearance of blood and of milk. 
819. How much cream should be obtained from good milk? 
820. What is the percentage of water in genuine milk? 
821. Name sources of vegetable casein and vegetable albumen. 
822. Give the percentage of nitrogen in albumenoid substances. 
823. Describe the chemical nature of Musk. 
824. In what lie the peculiarities of Gelatin ? 
825. To what extent do isinglass, glue, and size differ? 
826. Whence is Pepsin obtained ? 
827. How is pepsin prepared ? 
Soaps, Solid Fats, Fixed Oils, Volatile Oils, Camphors. 
General Relations.—Oils and fats are, apparently, almost as sim- 
ple in constitution as ordinary inorganic salts. Just as acetate of 
potassium (KC2H302) is regarded as a compound of potassium (K) 
with the characteristic elements of all acetates (02II302), so soft 
soap is considered to be a compound of potassium (K) with the ele- 
ments characteristic of all oleates (K18H3302), and hence is chemically 
termed oleate of potassium (KC18H3302). Olive oil, from which soap 
is commonly prepared, is mainly oleate of the trivalent radical gly- 
ceryl (C3II5), the formula of pure fluid oil being C3II53C18II3302, and 
its name olein. The formation of a soap, therefore, on bringing 
together oil and a moist oxide or hydrate, is a simple case of double 
decomposition, or, rather, metathesis, as seen already in connection 
with lead plaster (p. 209), or in the following equation relating to 
the formation of common hard soap:— 
FATTY BODIES. 
Hydrate of sodium 
(caustic soda). 
3NaHO + C„IL3C18IT,.,0., = 3NaC,,H„0. f C.IL3HO 
.1—O In 3d 
Oleate of glyceryl 
(vegetable oil). 
- - .1,1 - L 
Oleate of sodium 
(hard soap). 
i a o 
Hydrate of glyceryl 
(glycerin). 
Berthelot has succeeded in preparing oil artificially from oleic acid 
and glycerin, and it is said to be identical with the pure olein of 
olive and of other fixed oils. Hard fats chiefly consist of stearin—• 
that is, of tristearate of glyceryl (CSH53C18H3502). Mr. Wilson, of 
Price’s Candle Company, obtains stearic and oleic acids and gly- 
cerin by simply passing steam, heated to 500° or 600° F., through 
melted fat. Both the glycerin and fat acids distil over in the cur- 
rent of steam, the glycerin dissolving in the condensed water, the 
fat-acids floating on the aqueous liquid. 
Oleic acid (Acidum Oleicum, U. S. P.), when quite pure, is a light- 
yellow, almost inodorous, and tasteless oil, of sp. gr. 0.800 to 0.810. 
At low temperatures it thickens, and when near the freezing-point of 
water crystallizes, The occurrence of any important quantity of FATTY BODIES. 
463 
palmitic acid or stearic acid may be proved by saponifying with 
carbonate of potassium, neutralizing the product with acetic acid, 
precipitating with acetate of lead, washing the lead oleate with a 
little hot water, and adding ether: the oleate will dissolve the pal- 
mitate, and stearate of lead be insoluble. Any fixed oil will float 
on the surface when equal volumes of the oleic acid and of alcohol 
are \yarmed to 25° C. 
The author found (Pharmaceutical Journal, March, 1863) that oleic 
acid readily combines with alkaloids and most of the metallic 
oxides or hydrates, forming oleates which are soluble in fats. In 
this way active medicines may be administered internally in con- 
junction with oils or externally in the form of ointments. ( Oleatum 
Hydrecrgyri, U. S. P.; Oleatum Veratrince, U. S. P.) 
As regards the conversion of oily substances into emulsions resem- 
bling the common natural emulsion milk, Gregory states that 3 
drachms of gum-acacia in fine powder are necessary to emulsify 1 
ounce of any of the volatile oils, and that a little less (about 2 
drachms) will answer for the fixed oils and balsams. To this quan- 
tity of gum 44 drachms of water must be added (no more and no 
less). Either the water or the oil may be added first to the gum, 
but it is quickest to add the oil first, and well triturate before adding 
the water. 
Soaps.—Olive oil boiled with solution of potash yields po- 
tassium soap, or soft soap (Sapo Mollis, B. P. ; Sapo Viridis, 
U. S. P., or Green Soap); with soda, sodium soap, or hard soap 
(Sapo, U. S. P.); mixed with ammonia, an ammonium soap 
(Liniment-urn Ammonise, U. S. P. with cotton-seed oil) ; and 
with lime-water, calcium soap (Linimentum Calcis, U. S. P., 
with cotton-seed oil).—all oleates, chiefly of the respective 
basylous radicals. Their mode of formation is indicated in 
the foregoing equation. The alkali soaps are soluble in alco- 
hol, the others insoluble. A green soap, much used on the 
continent of Europe, and indeed official in Germany (formerly 
as Sapo Viridis, now as Sapo Kalinus Venalis), is made by 
adding indigo to ordinary soft soap, the yellow color of the 
soap yielding with the indigo a greenish compound. The 
official characters of Hard Soap are : “ Grayish-white, dry, in- 
odorous ; horny and pulverizable when kept in dry warm air ; 
easily moulded when heated; soluble in rectified spirit, leaving 
not more than 3 per cent, of insoluble matter, of which-at least 
two-thirds are soluble in water. A 4-per cent, alcoholic solution 
should not gelatinize on cooling (abs. of animal fats), not im- 
parting an oily stain to paper; incinerated, it yields an ash 
which does not deliquesce.” And of Soft Soap: “ Yellowish- 
green, inodorous, of a gelatinous consistence ; soluble in recti- 
fied spirit; not imparting an oily stain to paper; when dried 
yielding nothing to benzol ; incinerated, it yields an ash which 464 
FATTY BODIES. 
is very deliquescent.” Curd Soap (Sapo Animalis, B. P.) is a 
“ soap made with soda and a purified animal fat, consisting 
principally of stearin.” It will, of course, chiefly contain 
stearate of sodium. In pharmacy it is often advantageously 
employed instead of the “ hard soap.” Castile and Marseilles 
soaps are sodium soaps “ mottled ” by iron soap. 
The hard soap met with in trade is made from all varieties of oil, 
the commoner kinds being simply the product of the evaporated 
mixture of oil and alkali, while the better sorts have been separated 
from alkaline impurities, and the glycerin by the addition of com- 
mon salt to the liquors, which causes the precipitation of the pure 
soap as a curd. Potash soap is not prccipitable by salt. 
Bile (Fel Boris, U. S. P.) is, officially, the gall of the ox (Bos 
taurus, Linn.), either heated to 80° C., strained, and evaporated from 
100 parts to 15 (Fel Boris Inspissatum, U. S. P.), or freed from 
mucus by agitating with alcohol (in which mucus is insoluble), 
filtering, and evaporating. The latter is the official Purified Ox-Bile 
(Fel Boris Purificatum, U. S. P.); it has a resinous appearance, but 
is chiefly composed of two crystalline substances having the con- 
stitution of a soap; the one is termed taurocholate of sodium 
(NaC2elI42N06S), the other is glycocholate, or simply cholate of 
sodium (NaC2SlI44N07S). Both taurocholates and glycocholates are 
conjugated bodies readily yielding, the former cholic or cholalic acid 
(1IC241I3905) and taurine (C2II7N03S), the latter cholalic acid and 
glycocine or glycocoll (02H5N02), a soluble crystalline body having 
interesting physiological relations, inasmuch as it is obtainable from 
gelatin (hence the name glycocoll or sugar of gelatin, from 
gluciis, sweet, and koa'Ao, holla, glue) and from hippuric acid. The 
presence of bile in a liquid, such as urine, may be detected by the 
following tests: The fluid is gradually mixed with half its bulk of 
strong sulphuric acid in a test-tube, rise of temperature being pre- 
vented by partial immersion of the tube in water. A small quan- 
tity of powdered white sugar is then introduced and well mixed 
writh the acid liquid, and more sulphuric acid then poured in ; as 
the temperature rises a reddish or violet coloration is produced. 
The cholacic acid liberated in the reaction furnishes the color. 
This is Pettenkofer's test. It is somewhat interfered with by albu- 
men and by volatile oils. Quinlan tests for bile by placing a three- 
millimetre stratum of the suspected fluid before the slit of a spectro- 
scope and observing the absorption, which extends, according to the 
amount present, from the violet of the spectrum as far as the Fraun- 
hofer line I). 
Solid Fats.—1. Lard {Adeps, U. S. P.) is the purified internal fat 
of the abdomen of the hog—the perfectly fresh omentum or flare, 
washed, melted, strained, and dried. Lard Oil (Oleum Adipis, 
U. S. 1\), which is chiefly olein, is “ a fixed oil expressed from lard 
at a low temperature.” Sp. <rr. 0.900 to 0.920. 2. Benzoated Lard 
(Adepts Benzoinatus, U. S. P.) is lard heated over a water-bath with FATTY BODIES. 
465 
2 per cent of benzoin, which communicates an agreeable odor and 
prevents or retards rancidity. Lard is a mixture of olein and 
stearin; margarin, the margarate of glyceryl, was formerly sup- 
posed to be a constituent of lard and other soft fats, but is now 
regarded as a mere mixture of palmitin (the chief fat of palm oil) 
and stearin. 3. Yellow Wax (Cera Flava, U. S. P.), (sp. gr. 0.955 
to 0.967 ; melting-point 63° to 64° C.), the prepared honeycomb of 
the Hive-Bee, and the same bleached by exposure to sunlight. 
4. White Wax (Cera Alba, U. S. P.) (sp. gr. 0.965 to 0.975; melt- 
ing-point about 65° C.), according to Brodie, is chiefly a mixture 
of Cerotic Acid (IIC27Hj;j02), Palmitate of Melissyl (C30ir61C,Bn.jlO2), 
and about 5 per cent, of Ceroleine, the body to which the color, odor, 
and tenacity of wax are due. “ If 1 gm. of yellow wax be boiled, 
for half an hour, with 40 gm. of solution of soda (sp. gr. 1.180), the 
volume being preserved by the occasional addition of water, the wax 
should separate on cooling, without rendering the liquid opaque, 
and no precipitate should be produced in the filtered liquid by hy- 
drochloric acid (abs. of fats or fatty acids, Japan wax, resin); nor 
should the same reagent produce a precipitate in water which has 
been boiled with a portion of the wax (abs. of soap). If 5 gm. of 
wax be heated in a flask for fifteen minutes with 25 gm. of sulphu- 
ric acid to 160° C. (320° F.), and the mixture diluted with water, no 
solid, wax-like body should separate (abs. of paraffin).”—U. S. P. 
Cerecine, the purified native ozokerita (oC«, ozo, I smell; xvpfl, keros, 
wax) of Galicia, is a solid hydrocarbon largely used as a substitute 
for beeswax, especially in Russia. It differs from beeswax chem- 
ically in being almost unattacked by warm oil of vitriol. 5. Sper- 
maceti (Cetaceum, U. S. P.) is the palmitate of cethyl (C1BII33C1BII3102), 
or cetine; when saponified it yields, not glycerin, the hydrate of 
glyceryl (C3II53IIO), but ethal, the hydrate of cetyl (C1BII33IIO); it 
is the solid crystalline fat accompanying sperm oil in the head of 
the spermaceti whale. Sp. gr. about 0.945; melting-point near 
50° C. 6. Suet, the internal fat of the abdomen of the sheep, puri- 
fied by melting and straining, forms the official Sevum, U. S. P.; it 
is almost exclusively composed of stearin (C3II53C18FI3502). 7. Ex- 
pressed oil of nutmeg (Oleum Myristicce Expression, B. P.), com- 
monly but erroneously termed Oil of Mace, is a mixture of a little 
volatile oil with much yellow and white fat; the latter is myristin 
or myristate of glyceryl (C3H53CUH2702). 8. Oil of theobroma, or 
Cacao-butter (Oleum Theobrornce, U. S. P.), chiefly theobromate of 
glyceryl (Kingzett), is a solid product of the roasted and roughly 
crushed seeds or cocoa-nibs of the Theobroma cacao. They contain 
from one-fourth to one-half of this fat; melting-point 15° C. These 
also furnish, when ground, flake cocoa ; or when ground and much 
sweetened, chocolate ; or with farina and some sugar, cocoa ; or with 
a portion of the butter extracted, “cocoatina,” etc. 9. Cocoa-nut 
oil or butter, a soft fat largely contained in the edible portion of the 
nut of Cocos nucifera, or common cocoa-nut of the shops, a body 
containing glyceryl united with no less than six different univalent 
acidulous radicals—namely, the caproic (C6Hn02), caprylic (C8II]50.,), 
rutic (C10lI19O2), lauric (C12H2302), myristic (C]4II2702), and palmitic 466 
FATTY BODIES. 
(C16H3l02), radicals which, like some from common resin, when 
united with sodium, form a soap differing from ordinary hard soap 
(oleate of sodium) by being tolerably soluble in a solution of chlo- 
ride of sodium ; hence the use of cocoa-nut oil and resin in making 
marine soap, a soap which, for the reason just indicated, readily 
yields a lather in sea-water. 10. Kokum Butter, Garcinia Oil, or 
Concrete Oil of Mangosteen, a whitish oryellowish-wdiite fat obtained 
from the seeds of Garcinia indica or G. purpurea, is composed of 
stearin, myristicin, and olein. It is recognized officially in the 
Pharmacopoeia of India (Garcinice Purpurece Oleum). 
Butter yields 87 J per cent, of fat acids by saponification and de- 
composition of the soap by acid. Other animal fats, with which 
butter is likely to be adulterated, yield 95J. Hence the percentage 
of fat acid yielded by a suspected sample of butter indicates not 
only purity or the opposite, but the extent of sophistication. 
Fixed Oies.—Fixed and Volatile oils are naturally distinguished 
hy their behavior when heated ; they also differ generally in chem- 
ical constitution, a fixed oil being, apparently, a combination of a 
basylous with an acidulous radical, while a volatile oil is more com- 
monly a neutral hydrocarbon or the same oxidized. 
Drying and Non-drying Oils.—Among fixed oils, most of which 
are oleate with a little palmitate and stearate of glyceryl, a few, 
such—as (1) Linseed oil (Oleum Lini, U. S. P., contained in Linum, 
U. S. P., Linseed or Flaxseed, the ground residue of which “ should 
yield, when extracted with disulphide of carbon, not less than 25 
per cent, of fixed oil,” is linseed meal), and (2) Cod-liver oil (Oleum 
Morrhuas, U. S. P.), and to some extent castor and croton—are known 
as drying oils, from the readiness with which they absorb oxygen 
and become hardened to a resin. Linseed commonly contains 37 or 
38 per cent, of oil; 25 to 27 per cent, is obtained by submitting the 
ground seeds to hydraulic pressure, 10 or 12 per cent, remaining in 
the residual oil cake. Boiled oil is linseed oil which has been boiled 
with oxide of lead. This treatment increases the already great tend- 
ency of linseed oil to resinify, forming linoxyn, CS2H54011, on expo- 
sure to air. The drying oils appear to contain linolein, an oily 
body distinct from olein. Cod-liver oil contains a trace of iodine. 
Among the non-drying oils are the following: (3) Almond oil (Oleum 
Amygdalae Expression, U. S. P.), indifferently yielded by the bitter 
(Amygdala Amara, U. S. P.) or sweet seed (Amygdala Dulcis, 
U. S. P.) to the extent of 45 and 50 per cent, respectively. (3u) 
Cotton-seed oil (Oleum Gossypii Seminis, U. S. P.) contains olein 
and some palmitin. Sp. gr. 0.920 to 0.930. It should not be per- 
manently colored dirty yellow by sulphuric acid. (4) Croton oil 
(Oleum Crotonis, B. P., and Oleum Tigtii, U. S. P.). Geuther states 
that no such acid as crotonic is obtainable from croton oil, but acetic, 
butyric, valerianic, and higher members of the oleic series, together 
with tiglic acid, IIC5H702. (5) Lycopodium (U. S. P.), a yellow pow- 
der composed of the spores of the common Club-Moss (Lycopodium 
claoatum), contains a large proportion of a very fluid fixed oil 5 also FIXED OILS. 
467 
an alkaloid (Bodeker), C32H52N203. (6) Olive oil (Oleum Olivee, U. S. 
P.), already noticed (p. 462). “ If 1 gm. of olive oil be agitated in 
a testrtube with 2 gm. of a cold mixture prepared from equal volumes 
of strong sulphuric acid and of nitric acid of sp. gr. 1.185, and the 
mixture be set aside for half an hour, the supernatant oily layer 
should not have a darker tint than yellowish ; nor should a green 
or red layer separate on standing if 1 gm. of the oil be shaken for 
a few seconds with 1 gm. of a cold mixture of sulphuric acid (sp. 
gr. 1.830) and nitric acid (sp. gr. 1.250), and 1 gm. of disulphide of 
carbon ; and if 5 drops of the oil are let fall upon a thin layer of 
sulphuric acid in a flat-bottomed capsule, no brown-red or dark- 
brown zone should be developed within three minutes at the line 
of contact of the two liquids (abs. of appreciable quantities of other 
fixed oils of similar physical properties). —U. S. P. (7) Castor oil ( Ole- 
um Ricini, U. S. P.), chiefly a ricinoleate of glycei-yl (C3H53C18II3303) 
or ricinolein, a slightly oxidized olein, soluble, unlike most fixed 
oils, in alcohol and in glacial acetic acid. Castor-oil seeds are stated, 
by Tuson, to contain an alkaloid, ricinine. It possesses no purgative 
property. (8) Oil of Male Fern, a vermifuge obtained by exhausting 
the rhizome (Aspidium, U. S. P.) with ether and removing the ether 
by evaporation—a dark-colored oil containing a little volatile oil and 
some resin, and officially termed an oleoresin (Oleoresina Aspidii, 
U. S. P.). Its chief active constituent appears to be filicic acid, 
CHII,805. (9) Fixed oil of Mustard, a bland, inodorous, yellow or 
amber oil, yielding, by saponification and action of sulphuric acid, 
glycerin, oleic acid, and exude acid (IIC22II4102) (Darby). (10) 
Arachis oil (Oleum Arachis, P. I.) is found to the extent of 40 or 50 
per cent, in the seeds of Arachis hypogcea (P. I.), the Ground-nut or 
Eiirth-nut (so called because the pod of the herb in the growth of 
its stalk downward is forced beneath the surface of the ground, and 
there ripens). It is chiefly olein, but contains hypogaein, palmitin, 
and arachin. The oil is largely used in India in the place of olive 
oil, and is becoming much employed in Europe, especially for soap- 
making. (11) Sesame oil, or oil of sesamum ( Oleum Sesami, U. S. P.) 
(Gingelly, Teal, or Benne Oil), from the seeds of Sesamum indicum, 
is also largely used in Europe. It has most of the characters of the 
best olive oil. (12) Shark-liver oil, from Squalus carcharis (Oleum 
Squalce, P. I.), is used to some extent as a substitute for cod-liver oil 
in India. 
Their physical qualities and the formulae of their acidulous rad- 
icals show that the fatty bodies are closely related, and indicate 
that the natural processes by which they are formed are probably 
as closely related. The following Table shows the homology of the 
fat-acids, and gives their names, formulae, melting-points, boiling- 
points, and natural and artificial sources. (For further information 
respecting these acids and their isomers, the reader is referred to 
the Index, to works on Organic Chemistry, to larger chemical 
works, or to Watt’s Dictionary of Chemistry.) FATTY BODIES. 
Formulae. 
Melting- 
Boiling- 
Whence obtained. 
Vol. =2. 
point. 
0 F. 
0 C. 
0 F. 
0 C. 
f Red ants ; distillation 
of 
IIC II 02 
47.3 
8.5 
212 
100 
J oxalic acid ; and oxida- 
tion of amylaceous and 
{ other organic bodies. 
( Distillation of wood : 1 
IIC2 II3 02 
62 
16.7 
244.4 
118 
'O 
( hoi, etc. 
0 
Propionic ... 
IIC3 II5 02 
-5.8 
-21 
285.2 
140.7 
( Fermentation of gly- 
( cerin, etc. 
Butyric 
IIC4 II7 02 
32 
0 
324 
162.4 
(Butter: fermentation 
( of lactic acid, etc. 
.2 
*3 
Valerianic... 
hc5 h9 O2 
3.2 
-16 
365 
185 
j Valerian root; oxida- 
| tion of fusel oil. 
Caproic 
II c6 H11O2 
28.4 
-2 
401 
205 
Butter. 
0 
CEnanthylic. 
IIC7 II13O2 
19 
-10.5 
435 
224 
f Castor oil bydistilla- 
( tion, etc. 
0 
ts 
Caprylic 
HC8 II15O2 
61.7 
-16.5 
457 
236 
Butter; cocoa-nut oil. 
Pelargonic.. 
11C9 II17O2 
54.5 
12.5 
489 
254 
f Leaves of the geran- 
1 ium. 
0 
PQ 
HCioHi902 
86 
30 
516 
269 
( Butter; oil of rue by 
OX- 
j idation. 
HP,oTTo0n„nn 
43 
f Cocoa-nut oil; berries of 
( the bay tree. 
Myristic 
IIC14II27O2 
129 
54 
( Nutmeg-butter; coeoa- 
1 oil, etc. 
nut 
Palmitic 
HCi6H3102 
143.6 
62 
'* 
(Palm oil; butter; bees- 
{ wax, etc. 
Stearic 
TIC18H35O2 
159 
70.5 
.... 
Most solid animal fats. 
Arachidie ... 
HC20H39O2 
167 
75 
Butter; oil of ground-nut. 
Cerotic 
IIC27H5302 
174 
79 
Beeswax. 
Melissic 
llC30H59O2 
192 
89 
Beeswax. 
QUESTIONS AND EXERCISES. 
828. Give a sketch of the general chemistry of fixed oils, fats, 
and soaps. 
829. What is the difference between hard and soft soap? 
830. Which soaps are official ? 
831. Name the source of lard, and state how “Prepared Lard ” 
is obtained. 
832. State the composition of Beeswax. 
833. In what does Spermaceti differ from other solid fats? 
834. Mention the chief constituent of Suet? 
835. Whence is Cacao-Butter obtained ? 
836. Why is marine soap so called, and from what fatty matter is 
it almost exclusively obtained? 
837. What do you understand by drying and non-drying oils? 
838. In what respect does Castor Oil differ from other oils? 
839. How is oil of male fern (Ex. Filicis Liquidum) prepared? 
840. Mention the sources and formulae of the following fat-acids: VOLATILE OILS. 
469 
formic, acetic, propionic, butyric, valerianic, caproic, oenanthylic, 
caprylie, pelargonic, and rutic. 
Volatile Oils.—The Volatile or Essential Oils exist in various 
parts of plants, at first, probably, as mere combinations of carbon 
and hydrogen; but such hydrocarbons are prone to change when in 
contact with oxygen or moisture; hence these liquids, even when 
freshly obtained from the plants, and more especially as they occur 
in pharmacy, are usually mixtures of the liquid hydrocarbons or 
elceoptens (from c/mlov, elaion, oil, and b-royai, optomai, to see) (pp. 
469 to 475) with oxidized hydrocarbons, which are commonly solid 
or camphordike bodies termed stearoptens (from rrriap, stear, suet) 
(p. 475). The oils are also often associated with further oxidized 
bodies termed resins (p. 477). Of the hydrocarbons, those most 
commonly occurring are identical with or are isomers of that from 
oil of turpentine, and are known as terpenes. Tilden separates these 
terpenes into two groups: a turpentine group of true terpenes 
(C10HJ, whose members boil at 156° C. to 160° C., yield a nitroso- 
derivative melting at 129° C., and form a solid crystalline hydrous 
terpene (C10II20O2,lI2O) ; and an orange group (C13II24), polymerides 
of the true terpenes, whose members boii at 174° C. to 176° C., yield 
a nitroso-derivative melting at 71° C., and form no solid hydrous 
compound. Kingzett’s researches had previously pointed to a simi- 
lar grouping, for he showed that turpentine and the other similar 
hydrocarbons (C10IIlfi), and cymene (C101I14)—the probable nucleus of 
the terpenes—when mixed with water and subjected to a current of 
air, yielded to the water peroxide of hydrogen (not ozone), camphor, 
and camphoric acid, the peroxide of hydrogen and camphoric acid 
possibly resulting from the action of water on a camphoric peroxide 
(C,oHm04) ; while the second class (C15II24) yield no peroxide of hy- 
drogen. The members of the C10ll16 group are easily convertible 
into their polymers C151I24 and C20II32 by the action of heat, strong 
acids, etc. As regards either class, the members often differ from 
each other in their action on polarized light. Among the oxidized 
hydrocarbons occur several aromatic aldehyds; these, like ordinary 
aldehyds, form stable crystalline compounds with acid sulphite of 
sodium. On cooling a volatile oil, a stearopten often crystallizes 
out, or on distilling an oil it remains in the retort, being less vola- 
tile than an elaeopten. Volatile oils should obviously be preserved 
in well-closed bottles. Oxidation also proceeds more slowly in a 
cold than in a warm temperature. 
(For a paper by Symes on the varying power of a large number 
of essential oils to twist a ray of plane polarized light, see the 
Pharmaceutical Journal for September 13, 1879.) 
The process by which volatile oils are usually obtained from 
herbs, flowers, fruit, or seeds may be imitated on the small scale 
by placing the material (bruised cloves or caraways, for instance) 
in a tubulated retort, adapting the retort to a Liebig’s conden- 
ser, and passing steam, generated in a Florence flask, through 470 
FATTY BODIES. 
a glass tube to the bottom of the warmed retort. The steam 
in its passage through the substance will carry the oil over the 
neck of the retort into the condenser, and thence, liquefied and 
cooled, into the receiving vessel, where the particles of the oil 
will be found floating on the water. It may be collected by 
running off the distillate through a glass funnel having a stop- 
cock in the neck, or by letting the water from the condenser 
drop into an old test-tube which has a small hole in the bottom, 
or any similar tube placed in a larger vessel, the water and oil 
being subsequently run off separately from the tube as from a 
pipette. Volatile oils, like fixed oils, stain paper, but the stain 
of the former is not permanent like that of the latter. Oils 
of lemon and orange are sometimes obtained by mere pressure 
of the rind of the fruit. 
The following official (U. S. P.) waters are made hy distribu- 
ting 2 parts of volatile oil over the large surface afforded by 
four parts of cotton, and percolating with 1000 parts of dis- 
tilled water: Aquse Anisi, Oinnamomi, Fceniculi, Menthse 
Piperitse, Menthse Viridis. Aqua Aurautii Florum, U. S. P., 
and Aqua Posse, U. S. P., are obtained by distilling 40 parts 
of flowers with 200 of water. 
The presence of alcohol in an essential oil may be detected 
and its quantity estimated by shaking with an equal bulk of 
pure glycerin. The latter dissolves the alcohol, and is aug- 
mented in volume according to the amount of alcohol present 
(Boettger). For tests for the alcohol see page 429. 
A large number of volatile oils are employed in medicine, either 
in the pure state, in the form of saturated aqueous solution (medi- 
cated waters), solution of spirit of wine, 1 in 5 (Essentia Anisi and 
Essentia Mentha; Piperita;, B. P.) and 1 in 50 (Spiritus Cajaputi, 
Juniperi, Lavandula;, Mentha; Piperita’, Myristicce, Rosmarinf— 
B. P.), or as leading constituents in various barks, roots, leaves, etc. 
The strength of Spiritus Anisi, U. S. P., and Sp. Cinnamomi, U. S. 
P., is 10 of oil to 90 of alcohol. Sp. Mentha; Piperita?, U. S. P., and 
Sp. Menth. Viridis, U. S. P., are of similar strength, but also con- 
tain whatever may be extracted by the 100 parts of the spirit from 
1 part of the dried herb. Spiritus Aurantii, U. S. P., contains 6 of 
oil and 94 of alcohol; Sp. Gaultherice, U. S. P., Sp. Juniperi, U. S. P., 
Sp. Lavandulae, U. S. P., and Sp. Myristicce, U. S. P., contain 3 of 
oil and 97 of alcohol; Spiritus Lirnonis, U. S. P., is made with 6 of 
oil, 4 of freshly-grated lemon-peel, and alcohol sufficient to produce 
100 of filtered product. Perfumes (“scents” or “essences,” includ- 
ing “Lavender-Water” and “Eaude Cologne,” or “Cologne-Water, 
Perfumed Spirit or Spiritus Odoratus,” as it is termed in U. S. P.) 
are for the most part solutions of essential oils in spirit of wine or 
spirituous infusions of materials containing essential oils. The fol- 
lowing oils are, directly or indirectly, official in the Pharmaoopasias: 471 
VOLATILE OILS. 
1. Volatile oil of Bitter Almond (p. 416). 2. Oil of the fruits of 
Ajwain or Ornurn, Carum Ajowan, or Ptychotis Ajowan (Fructus 
Ptychotis, P. I.), contains cymol or cymene (C10lT,,) and a stearopten 
(Ajicain-ka-phul, flowers of ajwain) identical with thymol, <W>. 
3. Oil of Dill (Oleum Anethi, B. P.), a pale, yellow, pungent, acrid 
liquid distilled from dill-fruit; it contains a hydrocarbon, anethene 
(C10 1I16), and an oxidized oil (CJ0HuO) identical with the carvol of 
oil of caraway (Gladstone). 4. Oil of Aniseed (Oleum Anisi, U. S. 
P.), a colorless or pale-yellow liquid, sp. gr. 0.976 to 0.990, of sweet- 
ish warm flavor, distilled in Europe from the Anise-fruit (Pimpinella 
anisnm) (Anisum, U. S. P.), and in China from the fruit of Star- 
Anise (Illicium anisatum) (Illicium, U. S. P.); it is a mixture of a 
hydrocarbon isomeric with oil of turpentine and anethol, a stear- 
opten (C10II12) which crystallizes out at low temperatures. 5. Oil 
of Chamomile (Oleum Anthemidis, B. P.), a bluish, or, when old, 
yellow" oil, of characteristic odor and taste, distilled from chamomile 
flower-heads (Anthemis, U. S. P.). The official variety (Anthemis 
nobilis) yields about 0.2 per cent, of an oil composed of a hydro- 
carbon (C101I1B) and an oxidized portion (C10H16O2), which, heated 
with potash, gives angelate of potassium (KC5H702), whence is ob- 
tained angelic acid (HC5H702). According to Demareay, Kopp, and 
Kobig, the oil is a mixture of the angelates of butyl and amyl and 
similar bodies. The flower-heads of another variety, Matricaria 
chamomilla (Matricaria, U. S. P.), contain a stearopten (C10II16O) 
having the composition of laurel-camphor. 6. Oil of Ilorseradish- 
root (Armoracice Radix, B. P.) is, according to Hofmann, the sulpho- 
cyanate of butyl or tetryl (C4II9CNS); it is the chief active ingre- 
dient of Spiritus Armoracice Compositus, B. P. 7. Oil of Sweet- 
Orange peel (Aurantii Dulcis Cortex, U. S. P.) and Oil of Bitter- 
Orange rind (Aurantii Amari Cortex, B. P.; Oleum Aurantii 
Corticis, U. S. P.), the former the flavoring constituent of the 
official syrup of the peel (Syrupus Aurantii, U. S. P.),' and the oils 
of various species of Citrus—namely, 8, lemon (Oleum Limonis, U. 
S. P.), from Lemon Peel (Limonis Cortex, U. S. P.) ; 9, lime; 10, 
bergamot (Oleum Bergamii, U. S. P.); 11, citron, and a variety of 
citron termed cedra—resemble each other in composition, all con- 
taining hesperidene, a hydrocarbon (C15II24), and a small quantity of 
oxidized hydrocarbons (PioIIhP5,Ci5H1()0), and (Wright and I’iessc) 
((,20lI.i0O.!). Tilden states that lemon oil, distilled from the fresh 
peel, consists chiefly of a terpene (C10II16), boiling at 176° C., with 
small quantities of a terpene boiling below" 160° and a hydrous 
terpene; the odor of the oil being due to the mixture. Expressed 
lime-essence also contains a soft resin. 12. Oleum Aurantii Riorum, 
U. S. P., Oil of Neroli, or Orange-Flower (Aurantii Flores, U. S. P.), 
the aqueous solution of which is official in the forms of wrater (Aqua 
Aurantii Fiorum, U. S. P.) and syrup (Syrupus Aurantii Florum, B. P. 
and U. S. P.), contains a fragrant hydrocarbon (C101I16), colorless wrhen 
fresh, but becoming red on exposure to light, and an inodorous oxi- 
dized hydrocarbon. Strong acids, especially nitric, attack the oil in 
orange-flower wrater, coloring the fluid of a rose-tint. 13. Oil of Petit 
Grain, distilled from the leaves and shoots of the orange tree, con- 472 
FATTY BODIES. 
sists chiefly of a hydrocarbon apparently identical with that of oil of 
neroli. 14. The leaves of Boldo (Peumus boldus), a Chilian shrub 
(tonic and hepatic), yield 2 per cent, of essential oil (and, according 
to Bourgon and Yrerne, an alkaloid, boldine). 15. Oil of Buchu- 
leaves (Buchu, U. S. P.) consists chiefly of a fluid oil (C10lI18O) 
holding in solution a crystalline stearopten, diosphenol (CH1I2203) 
(Fluckiger). 16. Oil of Cannabis Indica (see p. 478). 17. Oil of 
(the lesser) Cardamom, from seeds of the capsules (Cardamomum, 
IJ. S. P.), is chiefly a hydrocarbon (010ll18) isomeric with oil of tur- 
pentine and a camphor resembling turpentine-camphor (C10lIlg3II2O). 
18. Oil of Cajuput (Oleum Cajuputi, U. S. P.) is a mobile bluish 
liquid, consisting chiefly of hydrous cajuputene or cajuputol (C10ll,g,- 
1I20). The latter, repeatedly distilled from phosphoric anhydride, 
yields cajuputene itself (C101I16), which has the odor of hyacinths. 
Fresh cajuput oil has a green hue, which is perhaps transient, for 
the color of the oil of trade is due to copper (Guibourt and llisted) ; 
certainly the green coloring-matter of pure cajuput oil is organic. 
19. Oil of Caraway-fruit (Carum, U. S. P.) (Oleum Carui, B. 1\ ; 
Oleum Carl, U. S. P.) is a mixture of carvene (C151I24) and carvol 
(C,olli40). 20. Oil of Cloves (Caryophyllus, U. S. P.; Oleum Caryo- 
phylli, U. S. P.) and of Pimento or Pimenta, U. S. P., or Allspice 
( Oleum Pimentee, U. S. P.), both heavier than water, contain a liquid 
hydrocarbon (C15H24), eugenic acid (C10H12O2), a solid body, eugenin, 
isomeric with the eugenic acid, a second crystalline substance, caryo- 
phyllin (C10lI16O), isomeric with common camphor, and a salicylic 
compound. 21. Oil of Cascarilla-bark (Cascarilla, U. S. P.) has not 
been fully examined. 22. Oil of Cinnamon-bark (Cinnamomum, 
U. S. P.) and of Cassia-bark is mostly hydride of cinnamyl or cin- 
namic aldehyd (C9lI7OII). Boiled with nitric acid, it furnishes hy- 
dride of benzoyl (C7H5011) and benzoic acid (IIC71I502), with chloride 
of lime yields benzoate of calcium (Ca2C7tI502), and with caustic 
potash gives cinnamate of potassium (KC9H702). The specific gravity 
of oil of Ceylon cinnamon is about 1.040, and of Chinese cinnamon 
(oil of Cassia) about l.OoO. Both are termed Oleum Cinnamomi in 
U. S. P. 23. Oil of Citronella, a grass oil, from Andropogon nardus, 
is chiefly composed of citronellol (C10II16O and C10II,8O, Wright), 
probably isomeric with the absinthol from the Artemisia; absinthium 
or wormwood (Absinthium, U. S. P.) (Gladstone). 24. Oil of Co- 
paiva or Copaiba (Oleum Copaiba;, U. S. P.) and, 25, of Cubebs 
(Oleum Cubebce, U. S. P.), are hydrocarbons, having the formulae 
Cj5H24. This cubebene is sometimes associated with a camphor, 
hydrous cubebene (015H24,H20). Oil of cubebs also contains a small 
quantity of a terpene (C10ll16). 26. Oil of Coriander (Coriandrum, 
U. S. P. ; Oleum Coriandri, U. S. P.) seems to have the composition 
of hydrous oil of turpentine (C10H16,H2O). 27. The fruits of Cumin 
or Cummin (Cuminum cyminum), an ingredient of many curry- 
powders, contain about 3 per cent., and those of Water Hemlock, or 
Cowbane (Cicuta virosa), about 1} per cent., of an essential oil com- 
posed of Cymol or Cymenc (C101IU) and Cuminol (C]0lI12O). The 
latter is an aldehyd readily uniting with alkaline bisulphites and 
by oxidation yielding Cuminic Acid (C10II12O2). Cymol also occurs VOLATILE OILS. 
473 
in Garden Thyme (Thymus vulgaris). 27a. The fresh flowering 
herb of Erigeron canaclense, or Canadian Fleabane, yields an essen- 
tial oil (Oleum Erigerontis, U. S. P.) 28. Eucalyptus globulus leaves 
(Eucalyptus, U. S. P.) furnish nearly 1 per cent, of an oil (Oleum 
Eucalypti, U. S. P.) of sp. gr. 0.917, the more volatile and chief 
portion of which is eucalyptol or cymene, and a terpene (C101IU 
+ 2C10II16), together with an oxidized portion, C10HuO and C10H16O. 
29. Elecampane-root, Inula Helenium {Inula, U. S. P.), by distilla- 
tion with water yields solid volatile helenin (C61I80), a camphor oil 
or inulol (C10II18O), and inulic anhydride (Cj5II2.,0;j). 30. Oleum 
Foeniculi, U. 8. P., Oil of Fennel-fruit (Fceniculum, U. S. P.) differs 
in odor, but contains the same proximate constituents as oil of anise. 
31. Oil of Geranium, or Ginger Grass oil, from Andropogon schce- 
nanthus and various species of Pelargonium, contains geraniol 
(C10II18O). Oil of Hedeoma or American Pennryoyal (Oleum Hedeomce, 
U. 8. P.) has a sp. gr. of about 0.940. 32. Grains of Paradise {Amo- 
mum melegueta), Guinea Grains or Melegueta Pepper, Semina Car- 
damomi Majoris, contain an essential oil (C101I16 and C10lIlfiO) and a 
highly pungent resin. 33. Oil of Juniper { Oleum Juniperi, U. S. P.), 
the active constituent of Juniper Tops and Berries (Juniperus, 
U. S. P.), contains a hydrocarbon (C10U16) which by contact with 
water yields a white crystalline hydrous compound (C10H16,H2O) and 
a polymeric hydrocarbon (C20II.i2). 34. Oil of Lavender {Oleum 
Lavandulae, U. S. P.), from the flowering tops or whole herb, and 
Oleum Lavandulae Florurn, U. S. P., from the flowers, of Lavandula 
vera {Lavandula, U. S. P.), has not been satisfactorily examined. 
34a. Oil of Myrcia {Oleum Myrcice, U. S. P.), oil of bay, or bay- 
berry oil (sp. gr. about 1.040), is obtained from the leaves of Myrcia 
acris. 35. Oil or butter or camphor of Orris {Iris forentina) is a 
soft solid lighter than water. Fluckiger and Hanbury found it to be 
chiefly myristic acid associated with a little essential oil. 36. Oil of 
Peppermint {Oleum Menthce Piperitce, U. S. P.) consists of a hydro- 
carbon, menthene (C10II18), different from that of most volatile oils, 
and hydrous menthene (C10lI,8,H2O), a crystalline stearopten. 37. 
Oil of Spearmint {Oleum Menthce Viridis, U. S. P.), the Common 
Mint of the kitchen-garden, contains a liquid having the formula 
CioHjoO or C10H18,H20; also, according to Gladstone, menthol 
(Ci„HuO), isomeric with carvol. 38. Oil of Pennyroyal {Mentha 
pvlegium) contains, according to Kane, C10lI16O. 38a. The leaves 
and tops of Melissa officinalis or Balm {Melissa, U. S. P.), yield a 
volatile oil containing a camphor. 39. Oil of Nutmeg {Oleum My- 
risticce, B. P. and IJ. S. P.), and of the arillus of the nutmeg or mace 
{Maris, U. S. P.), is composed of a hydrocarbon, myristicene (C10Illfi), 
and myristicol (C10II16O) (Gladstone). 39a. Oil of Origanum, from 
Origanum vulgare, or Wild Marjoram (Origanum, U. S. P.), is of a 
bright yellow and has an odor somewhat like peppermint; it is a 
mixture of a liquid hydrocarbon and a camphor which is deposited 
after long standing. 40. Oil or Otto or Attar of Cabbage-Rose Petals 
{Rosce. Centifolia, U. S. P.; Oleum Rosa;, U. S. P.) gives the frag- 
rance to rose-water {Aqua Rosce, B. P.). It resembles most other 
volatile oils in being composed of a hydrocarbon and an oxidized 474 
FATTY BODIES. 
portion, but differs from all in this respect, that the hydrocarbon is 
solid and is destitute of odor, while the oxygenated constituent is 
liquid and the source of the perfume. According to Fluckiger, the 
solid hydrocarbon (C16II34) yields succinic acid as the chief product 
of its oxidation by nitric acid, and in other respects affords evidence 
of belonging to the paraffin series of fats. 41. Rosmarinus, U. S. P., 
Oil of Rosemary-tops (Oleum Rosmarini, U. S. P.), exists in the 
plant to the extent of from lj to 3 parts per 1000. It chiefly con- 
sists of a hydrocarbon (C101I]6) resembling that from Myrtle, Ulyrtus 
communis, but also contains oxygenized oil and stearopten (C10lI16O 
and C]0II18O) in variable proportions. 42. Oil of Rue {Oleum Rata?, 
U. S. 1’.) contains a small quantity of hydrocarbon (C10II16), with 
some rutic aldehyd (C10lI20O), but, according to Greville Williams, 
is chiefly euodic aldehyd (CjjII220), some lauric aldehyd (C121I240) 
also being present. Gorup-Besanez and Grimm have obtained oil 
of rue (CuII220) artificially as one of the products of the destructive 
distillation of acetate and caprate of calcium. 43. Oil of Savine 
(Oleum Sabince, U. S. P.), from the tops of Juniperus Sabina or 
Savine {Sabina, U. S. P.), contains several hydrocarbons, but none 
isomeric with oil of turpentine (Tilden). 43a. Sage {Salvia, U. S. P.) 
contains about 40 per cent, of salviol, C10II16O; about 20 per cent, 
of two C10II16 hydrocarbons, boiling at 156° 0. and 167° C. respect- 
ively ; about 10 per cent, of a camphor, C10lI16O ; and about 10 per 
cent, of cedrene, C15II24 (Muir). 44. Oil of Elder-flowers (Sambucus, 
U. S. P.) occurs in very small quantity ; it has a butyraceous con- 
sistence: it contains a hydrocarbon, sambucene (C10II16), and prob- 
ably a camphor. 45. Oil of Sandal-Wood {Oleum Santali, U. 8. 1\), 
or oil of Santal, has not been thoroughly examined. It occurs to 
the extent of about 1 per cent, in the fragrant white or yellow sandal- 
wood of India, Santalum album, a small tree of the natural order 
Santalaceae, and not to be confounded with the Pterocarpvs santa- 
linus, a tree of the natural order Leguminosae, and furnishing the 
inodorous Red Sandal-Wood or Red Sanders-Wood of the dyer. * 
46. Oil of Sassafras-root, {Oleum Sassafras, U. S. P.), sp. gr. 1.094 
(Sassafras, U. S. P.), yields safren (C10ll16) and large quantities of 
a stearopten, safrol or sassajrol (t1,,,11lo0b2). 47. Oil of Mustard 
{Oleum Sinapis Volatile, U. 8. P.) is the sulphocyanate of ally 1 (p. 
453). If adulterated with alcohol its sp. gr. is below 1.015. 48. Oil 
of Sweet Flag {Acorus calamus) contains the hydrocarbon c10ii 16* 
(The rhizome, Calamus, U. S. P., also contains Acorin, a bitter 
glucoside.) 48a. The tops and leaves of Thuja occidentalis, or Arbor 
Vitae. {Thuja, U. S. P.), yields two oxygenated oils (also a bitter prin- 
ciple, pinipicrin). 49. Oil of Turpentine {Oleum Terebinthinee, 
U. S. 1\). Turpentine itself is really an oleo-resin of about the con- 
sistence of fresh honey. It flows naturally or by incision from the 
wood of most coniferous trees, larch {Larix European) yielding 
Venice turpentine, Abies balsamece furnishing Canadian turpentine, 
Balsam of Fir or Canada Balsam {Terebinthina Canadensis, U. 8. P.), 
the bark of Pistachia terebinthus, the variety termed Chian Turpen- 
* Santalum Rubrum, U. S. P. CAMPHORS. 
475 
tine (containing about 1 part of essential oil to 7 of resin), and the 
Pinus palustris, P. australis, P. abies, P. pinaster, and P. tceda 
affording the common American turpentine, Terebinthina, U. S. P. 
Pinus maritima gives the French or Bordeaux turpentine, and P. 
picea, the old fragrant Strasburg turpentine. By distillation tur- 
pentine is separated into rosin or resin (p. 477), which remains in the 
still, and essential oil of turpentine, often termed simply turpentine, 
spirit of turpentine, or “ turps," which distils over. Mixed with 
alkali to saturate resinous acids, and redistilled, oil of turpentine 
furnishes about 80 per cent, of rectified oil of turpentine. Under the 
influence of heat, chemical agents, or both, pure oil of turpentine 
(C10II16) yields many derivatives of considerable chemical interest. 
The terpene of Bordeaux turpentine (terebenthene) rotates a ray of 
polarized light more than, and in the opposite direction to, the terpene 
of American turpentine. 50. Oil of common garden Thyme ( Thymus 
vulgaris), Oleum Thymi, U. S. P., is composed of cymene or cymol 
(C10II14), thymene (C10ll18), and thymol (C10U14O) (Thymol, U. S. P.). 
Thymol is also contained in (50a.) Oil of Horsemint (Monarda). 
Thymol crystallizes out when oil of thyme or of ptychotis, etc. is 
kept at a low temperature for a day or two. It may also be obtained 
by shaking the oils with caustic alkali and treating the separated al- 
kaline liquid by an acid. It may be purified by distillation or crystalli- 
zation from alcohol. It would seem that as an antiseptic thymol is far 
stronger than carbolic acid. 51. Oil of turmeric {Curcuma longa) is said 
by Jackson and Menke to be chiefly an alcohol having the formula 
C19H27HO. They name it turmerol. It is a light yellow volatile oil, 
having the sp. gr. 0.902. It is to this oil that turmeric (and, there- 
fore, curry-powder) owes its flavor and odor. 52. Oil of Valerian- 
root ( Valeriana, U. S. P.) ( Oleum Valeriance, U. S. P.) is a mixture of 
a hydrocarbon, valerene or borneene (C10fl16), and valerol (CelI10O). 
Valerol slowly oxidizes to valerianic acid, known by its smell. A 
similar change occurs at once if oil of valerian be allowed to fall, 
drop by drop, on heated caustic potash: C6II10O + 3KJIO -f- 1I20 
= K2C03 + K.C5II902 + 3IIj. By the action of sulphuric acid on 
the valerianate of potassium thus produced, valerianic acid is ob- 
tained. 53. Oil of Verbena, Lemon-Grass Oil, or Indian Melissa 
Oil, is obtained from Andropogon citratus (Oleum Andropogi Citrati, 
P. I.). 54. Oil of Ginger (Zingiber, U. S. P.) is, according to Thresh, 
a complex mixture of hydrocarbons and of their oxidation products. 
Cymene (C101I14) is present, a terpene, adehyds, and ethereal salts. 
(For an analysis of ginger, by Thresh, and for a paper on “Soluble 
Essence of Ginger,” see the Pharmaceutical Journals for August 30 
and September 6,1879, and March 4, 1882.) 55. American worm- 
seed (Chenopodium, U. S. P.) contains a volatile oil (Oleum Cueno- 
podii, U. S. P.). 
Camphors.—In addition to the stearoptens or camphors already 
mentioned as being contained in or formed from volatile oils, there is 
one that is a common article of trade. It is obtained from the wood 
of Cinnamomum camphora, or Camphor-Laurel, in Japan (termed in 
Europe “ Dutch Camphor,” because imported by the Dutch) and in 476 
FATTY BODIES. 
China (known as “Formosa Camphor”) by a rough process of dis- 
tillation with water, and is purified by resublimation (Camphora, 
U. S. P.). The formula of laurel-camphor is C10IIlfiO.; sp. gr. 
0.990 to 0.995; melting-point 175° C.; boiling-point 205° C. Bro- 
mine heated with camphor gives monohrom camphor (C10H,-BrO) 
and hydrobromic acid. Monobromated camphor (Camphora Mono- 
brornata, U. S. P.) is camphor in each molecule of which an atom 
of hydrogen has been displaced by one of bromine. Recrystallized, 
it occurs in white prisms. It melts at 65° C. and boils at 274° C. 
The essential oil from which doubtless camphor is derived by oxida- 
tion is easily obtained from the wood, and is occasionally met with 
in commerce under the name of liquid camphor or camphor oil; its 
formula is C20lI32O; by exposure to air it becomes oxidized and de- 
posits common camphor, 2C20II32O 02 = 4C]01 IlfiO. Camphor dis- 
tilled with phosphoric anhydride yields cymol, C10IIU. There is 
another kind of camphor in European markets less common than 
laurel-camphor, but highly esteemed by the Chinese; it is obtained 
from the Dryobalanops aromatica, and denominated Sumatra or 
Borneo camphor. It differs slightly from laurel-camphor in con- 
taining more hydrogen, its formula being C10lI]8O. It is accom- 
panied in the tree by a volatile oil (C10II]B) isomeric with oil of tur- 
pentine. This oil, borneene, is also occasionally met with in trade 
under the name of liquid camphor or camphor oil, but differs from 
laurel-camphor oil in not depositing crystals on exposure to air. 
Camphor is soluble to a slight extent in water (40 grains per gallon, 
Pooley). The official Camphor-water (Aqua Camphoroz, U. S. P.) is 
such a solution. 
Common camphor, and many other of the camphors, oily hydro- 
carbons, and oxidized hydrocarbons, yield camphoric acid (C10H16O4) 
and camphoretic acid (C10IIuO7) when attacked by oxidizing agents. 
Such reactions indicate natural relationships. Camphoric acid is a 
good antiseptic. 
Cantharidin (C5IIB02), the active blistering-principle of cantharides 
(Cantharis, U. S. P.) and other vesiccating insects (such as Mylatris 
cichorii, or Telini Fly, P. I., common in India), has most of the 
properties of a camphor or stearopten. It slowly crystallizes, from 
an alcoholic tincture of the beetles, in fusible, volatile, micaceous 
plates. The following process for the extraction of cantharidin is 
by Fumouze: Powdered cantharides are macerated with chloroform 
for twenty-four hours, and this treatment is repeated twice with fresh 
quantities of solvent, the residue having been well squeezed each 
time. The collected solutions are then distilled, and the dark-green 
residue treated with bisulphide of carbon, which dissolves fatty, 
resinous, and other matters and precipitates the cantharidin. The 
precipitate is thrown on a filter, washed with bisulphide of carbon, 
and recrystallized from chloroform. The same process, omitting the 
final recrystallization, may be used for the quantitative estimation 
of cantharidin in cantharides. The average quantity found is from 
4 to 5, but occasionally from 10 to 12, parts in 1000. Cantharidin 
is readily soluble in warm glacial acetic acid (Tichborne), and still 
more readily in acetic ether. Cantharides from which the fat has RESINS. 
been removed by petroleum ether yields the cantharidin with great 
facility. 
Massing and Dragendorff consider cantharidin to be an anhydride 
(C5II602), and that with the elements of water it forms cantharidic 
acid (II2C5II603). A cantharidate of potassium has the composition 
KIIC5H603. Piccard gives the vapor-density of cantharidin as about 
6.5, and its formula c10h12o4- 
841. How do volatile oils usually differ chemically from fixed oils? 
842. What are the general chemical characters of volatile oils? 
843. Describe the usual process by which volatile oils are obtained. 
844. Mention the differences in composition between the volatile 
oils of Anlhemis nobilis and Matricaria chamomilla. 
845. Give the systematic name of oil of horseradish. 
646. State the general composition of the oil of lemon, lime, ber- 
gamot, citron, and cedra. 
847. Name the constituents of oil of cloves. 
848. In what respect does oil (or otto) of roses differ from other 
volatile oils? 
849. To what class of substances do the constituents of oil of rue 
belong ? 
850. IIow does natural turpentine differ from the turpentine of 
trade? 
851. With what object is commercial turpentine rectified? 
852. How is camphor oil related to camphor? 
853. In what respects do Borneo or Sumatra camphor and cam- 
phor oil differ from the corresponding products of Japan and China? 
854. What is the nature of cantharidin? 
QUESTIONS AND EXERCISES. 
RESINOID SUBSTANCES. 
Resins occur in plants generally in association with volatile oils. 
They closely resemble camphors or stearoptens, hut are not volatile, 
and differ from oils and fats mainly in being solid and brittle. Oleo- 
resins are mixtures of a resin and a volatile oil. Gum-resins are 
mixtures of a resin or oleo-resins and gum. Balsams are commonly 
described as resins or oleo-resins which yield benzoic or cinnamic 
acid, but oleo-resins containing neither of these acids are often 
termed balsams; e. g., balsam of copaiva and Canada balsam. A 
physico-chemical method for the identification of the chief resins, 
gum-resins, and balsams will be found in the; Pharmaceutical Jour- 
nal for Nov. 17, 1877. Resins appear to be somewhat antiseptic. 
Beer is said never to turn sour in casks lined with Burgundy pitch. 
The resin of hops has, perhaps, a similar effect in retarding oxida- 
tion of alcohol. 
Resins, Oi.eo-Resins, Gum-Resins, Balsams. 478 
RESINOID SUBSTANCES. 
Resins.—1. Resin, rosin, or colophony (Resina, U. S. P.) is the 
type of this class. Its source is the oleo-resin or true turpentine of 
the conifers, a body which by distillation yields spirit of turpentine 
and a residuum of rosin. “Brown” and “White” rosin are met 
with in trade. The former is the residue of American, the latter of 
Bordeaux, turpentine (from Finns aides, etc. and Pinus maritima, 
respectively). The chief constituents of brown resin are pinic acid 
(IIC2#lI2902) and sylvic acid, identical in composition, but differing 
in properties (vide Isomerism), the former being soluble and the 
latter insoluble in cold spirit of wine. White resin or “ galipot ” is 
chiefly pimaric acid, also isomeric with pinic acid. Pinic acid 
heated yields colophonic or colopholic acid. Among the products of 
the destructive distillation of resin Tiehborne has found “ colopho- 
nic hydrate" (C10II22O3,II2O), a white inodorous crystalline substance, 
and by depriving this of water has obtained white crystalline colo- 
phonine (Cj0lI22O3). Resin is soluble in oil of turpentine. Contact 
with sulphuric acid immediately colors it strongly red. 2. Arnicin 
(C20II;S0O4), the chief acrid if not the only active principle of Arnica 
(Arnicas Radix, B. P.; Arnicas Flores, U. S. P.), is a resin. 3. Can- 
nabin, said to be the active principle of Indian llemp or Indian Can- 
nabis (Cannabis Indica. U. S. P., the flowering tops of the female 
plant of Cannabis saliva) and American Cannabis (Cannabis Amer- 
icana, U. S. P., the Cannabis sativa plant grown in the United 
States), was obtained in 1846 by T. and II. Smith, and is a resin. 
Personne in 1857 isolated a volatile oil said to possess much medici- 
nal activity, consisting of cannabene (ClgII20) and a solid crystalline 
‘■‘‘hydride of cannabene" (C18II22). 4. Capsicum-fruit contains resin 
(p. 479). 5. Castorin, a resinous matter, is the name given to the 
chief constituent of Castor (Castoreum, B. P.), the dried preputial 
follicles and included secretion of the beaver (Castorfiber). 6. Co- 
pal. The best copal is the exuded resin of trees of extinct forests, 
and is found beneath the surface of the ground in the neighborhood 
of existing trees. It appears to be a mixture of acids, but its cha- 
racter is still obscure. 7. Dragon's Blood, a crimson-red resin found 
as an exudation on the mature fruits of a Rotang or Rattan Palm 
(Calamus draco). It is said to be a definite substance, and to have 
the formula C20II20O4. 8. Ergotin is a very active resinoid constit- 
uent of Ergot (Ergota, U. S. P.), or the “ sclerotium (compact my- 
celium or spawn) of Clariceps purpurea, produced within the pal cm 
of the common rye, Secale cereale." Maize or Indian Corn, Zea 
mays, appears to foster a similar parasite, the Ustilago maydis, or 
Corn Smut (Ustilago, U. S. P.). According to Wenzell, ergot con- 
tains two alkaloids, ecboline and ergotine, to the former of which, he 
says, the activity of ergot is due. Blumberg considers these alka- 
loids to be identical. Tanret states that an unstable alkaloid termed 
ergotinine occurs in ergot, and to the extent of 1 per 1000, and that it 
is accompanied by a camphor. Dragendorff and Podwissotzky assert 
that ergot owes most of its activity to sclerotic or sclerotinic acid, 
present to the extent of about 4 per cent. No separated principle 
representing the full activity of ergot has yet been extracted from 
that drug. The same may be said of a similar therapeutical agent, OLEO-RESINS. 
479 
the root-bark of Gossypium herbaceum (Gossypii Radicis Cortex, 
U. S. P.), the activity of which appears to reside in a red resin. 
9. Guaiacum resin is a mixture of several substances (p. 421). 
10. Jalap resin (p. 422). 11. Kousso, or Kooso (Brat/era, U. S. P.), 
yields yellow crystals of a resinoid body readily soluble in alkaline 
liquids, kosin or koussin (C31II38O]0). 12. Mastic (Mastiche, U. S. P.) 
is a resinous exudation obtained by incision from the stem of the 
Mastic or Lentisk tree. Nine-tenths of mastic is mastichic acid 
(C20II31O2), a resin soluble in -alcohol; the remaining tenth, masticin 
(C20Il31O), a tenacious elastic resin. 13. Mezereon (Mezereum, U. S. 
P.), the dried bark of Daphne mezereum, Mezereon, and Daphne 
laureola, Spurge Laurel, owes its acridity to a resin. 14. Pepper 
contains a resin (p. 397). 15. Burgundy Pitch (Pix Burgundica, 
U. S. P.) is the melted and strained exudation from the stem of the 
Spruce Fir, Abies excelsa. The term Burgundy is a misnomer, the 
resin never having been collected at or near Burgundy; Finland, 
and to a smaller extent Baden, and Austria being the countries 
whence it is derived. Its constituents closely resemble those of 
common resin. It is often adulterated and imitated by a mixture 
of resin with palm oil, water, etc., from which it may be readily 
distinguished by its duller yellow color, highly aromatic odor, 
greater solubility in alcohol, and almost complete solubility in 
twice its weight of glacial acetic acid (Hanbury). 16. Podophyl- 
lum resin. In preparing the resin of podophyllum, or May-apple 
(Resina Podophylli, U. S. P.), an alcoholic extract of the rhizome 
and rootlets of Podophyllum peltatum (Podophyllum, U. S. P.) is 
poured into cold water acidulated by hydrochloric acid. This resin 
is the chief active principle of podophyllum-root. According to 
Guareschi, podophyllin contains a glucoside resembling convolvulin. 
Podwissotzkv has extracted from podophyllin a little coloring-mat- 
ter, fat, a bitter crystalline acid, a bitter crystalline neutral prin- 
ciple, and an amorphous acid resin. 17. Pyrethrin is the name of 
the acrid resinous active principle of the root of Anacyclus pyre- 
thrum, or Pellitory-root (Pyrethrum, U. S. P.). According to Buck- 
heim, the action of alkalies breaks it up into piperidine and pyre- 
thric acid. (The crystalline poisonous principle obtained by Bellesme 
from Pyrethrum carneum, the powder of which (and of P. roseum, 
and especially P. cinerarias folium, or Dalmatian Insect-Powder) is 
the well-known “insecticide,” has not yet been analyzed.) 18. The 
resins of Rhubarb have already been alluded to in connection with 
Crysophanic Acid (p. 335). 19. Rottlerin is the name given by 
Anderson to a crystalline resin from Kamala (Kamala, U. S. P.), 
the minute glands that cover the capsules of Rottlera tinctoria: to 
this and, apparently, allied resins, Kamala owes its activity as an 
anthelmintic. 
Oleo-Resins.—1. Cqpsicin, a term suggestive of a definite chem- 
ical substance, is a name somewhat unhappily accorded to an indef- 
inite substance, an oleo-resin, obtained bv digesting the alcoholic 
extract of Capsicum-fruit (Capsicum, U. S. P.) in ether and evap- 
orating the clear ethereal fluid to dryness. Besides volatile oil and 480 
RESINOID SUBSTANCES. 
resin, capsicum-fruits contain much fatty matter, which Thresh 
states is chiefly free palmitic acid. (See also Capsicine and Cap- 
saicin, p. 394.) 2. Copaiva (Copaiba, U. S. P.), sp. gr. 0.940 to 
0.993, is a mixture of essential oil (C15H24), with 2 or more per cent, 
of brown soft resin, and 30 to 60 of a yellow dark crystalline resin 
termed Copaivic acid Copaiva, containing about equal 
parts of this acid and of the oil, heated with a fourth of its weight 
of the official carbonate of magnesium, yields a transparent fluid, 
owing to the formation of copaivate of magnesium and solution of 
this soap in the essential oil. With an equal weight of the carbo- 
nate enough soap is produced to take up the whole of the essential 
oil and form a mass capable of being rolled into pills. A much 
smaller quantity of calcined magnesia, as might be expected, effects 
the same result; but more time, often several days, is required 
before complete reaction is effected. The Massa Copaiba?, U. S. P., 
is formed from 6 parts of magnesia and 94 of copaiba. Quicklime 
has a similar effect. Perhaps carbonate reacts more quickly because 
of its line state of division and admixture of hydrate ; in which case 
hydrates of calcium and magnesium may be expected to act better 
than the calcined preparations, and in much smaller quantity than 
carbonate of magnesium. Copaiva, unlike, 3, Wood Oil or Gurjun 
Balsam (Dipterocarpi Balsamum, P. I.), a similar oleo-rcsin from 
the Dipterocarpus turbinatus {])'. Lcevis, P. I.), does not become 
gelatinous when heated to 270° F. Copaiva is often slightly fluo- 
rescent ; Gurjun balsam is highly fluorescent. The stated analogy 
of Gurjun balsam to copaiva is borne out by its chemical composi- 
tion, for by distillation it yields about 40 per cent, of an essential 
oil identical in composition with oil of copaiva, the non-volatile por- 
tion being resinous. The adulteration of copaiva with ftxed oil is 
best detected by heating 20 or 30 drops in a capsule until all essen- 
tial oil has evaporated. Turpentine is betrayed by its odor during 
this evaporation. The residue, copaiva resin, is brittle if pure, and 
more or less sticky or soft if fixed oil is present. The limit of brit- 
tleness is stated, by Siebold, to be reached when 1 per cent, of oil 
has been added to the copaiva, that amount preventing the residue 
being reduced to a fine powder. “ The essential oil distilled off 
from the oleo-rcsin, when rectified, should not begin to boil below 
200° C. (392° F.). On adding 1 drop of copaiba to 19 drops of 
disulphide of carbon and shaking the mixture with 1 drop of a cold 
mixture of equal parts of sulphuric and nitric acids, it should not 
acquire a purplish-red or violet color (absence of gurjun balsam).” 
—U. S. P. Resina Copaibce, U. S. P., is the residue left after dis- 
tilling off the volatile oil from copaiba. 4. Elemi (Elemi, B. P.) is 
an exudation from a tr.ee growing in the Philippine Islands. It 
consists of volatile oil (C10II16) with 80 or more per cent, of two 
resins, the one (C20II32O2) soluble in cold alcohol, the other, amyrin, 
(C5II8)5II20, almost insoluble, associated with amyric acid, (C5IIg)704 
(Buri). It also contains small quantities of two crystalline bodies 
soluble in water, bryoidin, (C5H8)43II20, and breidin (Fluckiger). 
The icacin of Stenhouse and Groves is either identical with amyrin 
or perhaps has the formula (C5II8)alI20. All these bodies are prob- GUM-RESINS. 
481 
ably hydrous terpenes. 5. Wood-Tar (Pix Liquida, U. S. P.) is a 
mixture of several resinoid and oily bodies (amongst others Creasote, 
p. 449) obtained by destructive distillation from the wood of Finns 
sylvestris and other pines. When heated it yields an almost color- 
less terebinthinate oil (Oleum Picis Liquidce, U. S. P.), Oil of Tar, 
sp. gr. 0.970, which soon becomes brown, and a residue of pitch. 
6. Turpentines.—These oleo-resins have been mentioned in connec- 
tion with oil of turpentine, their volatile, and resin, their fixed, con- 
stituent. 7. Common Frankincense (Thus Americanum, B. P.) is 
the concrete turpentine of Pinus tceda. 8. Canada Balsam (Tere- 
binthina Canadensis, B. P.), largely gathered in the province of 
Quebec, is the turpentine or oleo-resin of Balm of Gilead Fir 
(Abies balsamea). 9. Sumbul-root, from Ferula sumbul (Sumbul, 
U. S. P.), seems to owe its stimulating property to two oleo-resins, 
one soluble in ether, the other in alcohol. 10. Oleo-resin of Lu- 
pulin (U. S. P.) is an ethereal extract of the yellow powder (Lu- 
pulinum, U. S. P.) attached to the small nuts at the base of the scales 
which form the aggregate fruit of the Hamulus lupulus, or IIop 
(Hamulus, U. S. P.). It contains essential oil of hop (Valero!, 
C6II10O) and oxidized oil or resin, bitter extract containing the hop- 
bitter, lupulinic acid (C.12lI5nG7), and tannic acid. Oleoresince As- 
pidii, Capsid, Cubebce, Piperis, and Zingiberis are official in the 
United States Pharmacopoeia. 11. Pix Canadensis, U. S. P., Can- 
ada Pitch or Hemlock Pitch, is the concrete juice of Abies canadensis. 
Gum-Resins.—1. Ammoniacum (Ammoniacum, U. S. P.) is an ex- 
udation from the Dorema ammoniacum. It contains nearly 20 per 
cent, of gum, a little volatile oil, and about 70 of resin (C40U50O9— 
Johnston). 2. Asafcetida (Asafcetida, U. S. P.) is a gum-resin ob- 
tained, by incision, from the living root of Ferula narthex and F. 
scorodosma. It contains from 50 to 70 per cent, of a resin which 
is partly ferulaic acid (C10II10O4), 25 to 30 per cent, of gum (about 
two-thirds arabin, one-third bassorin, p. 113), and 3 to 5 per cent, 
of volatile oil. At least 60 per cent, of it should be soluble in 
alcohol. 3. Euphorbium, an old drug which is an emetic and pur- 
gative resin. It contains an amorphous active resin (C20II32O4), 
crystalline euphorbon (C2BII4402), and mucilage (Fliickiger). 4. The 
ordinary or Siam Gamboge (Cambogia, U. S. P.) of European trade 
is obtained from the Garcinia Hanburii; the gamboge of India 
(Cambogia Indica vet Mysoriensis, P. I.) from G. pictoria. When 
of best quality it contains about 20 per cent, of a gum and 80 to 75 
per cent, of a resin termed gambogic acid (C.,0II23O4). 5. Galbanum 
(Galbanum, U. S. P.) contains from 20 to 25 per cent, of gum, about 
65 per cent, of resin (C40II54O7), and 3 or 4 per cent, of volatile oil. 
Moistened with alcohol, and then with hydrochloric acid, galbanum 
yields a purple color, due, probably, to the production and oxidation 
of resorcin. Galbanum, heated for some time to 212° F. with hydro- 
chloric acid, the liquid separated and shaken with ether or chloroform, 
and the latter evaporated, yields somewhat less than 1 per cent, of 
colorless acicular crystals of umbelliferone (C91IB03).* 6. Myrrh 
* “ Umbelliferone is soluble in water; its solution exhibits, espe- 482 
RESINOID SUBSTANCES. 
(Mgrrha, U. S. P.), an exudation from the stem of Balsamodendron 
myrrha, contains about half its weight of soluble gum (arabinoid), 
10 per cent, of insoluble gum (probably bassorin), 2<| of volatile oil, 
and about 25 per cent, of resin (myrrhic acid). (For a note by 
11. H. Parker on the spurious gums imported with myrrh, see the 
Pharmaceutical Journal for July 17, 1880.) 7. Olibanum (P. 1.), 
Thus musculum, or Arabian Frankincense (from various species 
of Boswellid), is about one-third gum and nearly two-thirds resin 
(C40II.)0O6), with a little hydrocarbon (C10II16) and oxidized hydro- 
carbon volatile oils. It has always been an important ingredient 
of incense—myrrh, storax, benzoin, and such fragrant combustible 
resinous substances being other constituents. 8. Scummony (p. 424). 
Gum-resins need only be finely powdered and rubbed in a mortar 
with water to yield a medical emulsion, in which the fine particles 
of resin are held in suspension by the aqueous solution of gum. 
Balsams.—1. Benzoin (Benzoinum, U. S. P.) is obtained from in- 
cisions of the bark of Sty rax benzoin. It contains 12 to 15 per cent, 
of benzoic acid (p. 332), about 50 per cent, of a resin (a) soluble 
in ether, 25 to 30 per cent, of a resin (/3) soluble in alcohol only, 
and 3 to 4 per cent, of a resin (y) soluble in solution of carbonate 
of sodium. The a resin is considered to be a compound of the [3 
(C40II46O9) and the y (C30II40O5). The balsams of Peru, Tolu, and 
Storax differ from benzoin in containing cinnamic (p. 472) in place 
of benzoic acid; hence they yield, by oxidation, hydride of benzoyl 
(oil of bitter almonds). 2. Balsam of Peru (Balsamum Peruvianum, 
U. S. P.), from the Myroxylon pereira’, is a mixture of oily matter 
with about one-quarter or one-third of resinous matter and 6 per 
cent, of cinnamic acid. The oil, by fractional distillation in an atmo- 
sphere of carbonic acid gas and under diminished pressure, .fur- 
nishes benzylic alcohol (C71I7II0), benzoate of benzyl (C7II7C-H502), 
and cinnamate of benzyl (C71I7C9II702) or cinnamein (Kraut). By 
action of alcoholic solution of potash it yields benzoate and cin- 
namate of potassium and benzylic alcohol; also cinnamic alcohol 
(C91I9II0), otherwise known as peruvine or styrone; it also often 
holds in solution metacinnamttin or styracin (018II]602), isomeric 
with hydride of cinnamyl (C9II7OII). The resin of balsam of Peru 
cially on addition of an alkali, a brilliant blue fluorescence which is 
destroyed by an acid. If a small fragment of galbanum is immersed 
in water, no fluorescence is observed, but it is immediately produced 
by a drop of ammonia. The same phenomenon takes place with asa- 
foetida, and to a slight degree with ammoniaeum; it is probably due 
to traces of umbelliferone pre-existing in those drugs. Umbelliferone 
is also produced from many other aromatic umbelliferous plants, as 
Angelica, Levisticum, and Meum, when their respective resins are sub- 
mitted to dry distillation; also from the resin of Daphne mezerevm. 
The fluorescence of umbelliferone may be beautifully shown by dipping 
some bibulous paper into water which has stood for an hour or two 
on lumps of galbanum, and drying it. A strip of this paper placed 
in a test-tube of water with a drop of ammonia will give a superb 
blue solution, instantly losing its color on the addition of a drop of 
hydrochloric acid.” (Fliickiger and llanbury.) BALSAMS. 
483 
seems to result from the action of moisture on the oil. When mixed 
with 3 parts of bisulphide of carbon, about 40 per cent, of resin 
separates, and the liquid portion should be transparent, of a light- 
brown color and exhibit only a faint fluorescence (abs. of Gurjun bal- 
sam).—U. S. P. The constituents of Vanilla, U. S. P., the prepared 
unripe pods of a plant, somewhat resemble those of balsam of Peru. 
The crystals often found on vanilla are a weak acid substance hav- 
ing the formula C16H1606 (Carles). 3. Balsam of Tolu (Balsamum 
Tolutanum, U. S. P.) is an exudation from incisions in the bark of 
Myroxylon toluifera; in composition it closely resembles balsam of 
Peru, but is more susceptible of resinification. It contains benzoate 
and cinnamate of benzyl, cinnamic acid, a little benzoic acid (Busse), 
and about l per cent, of a volatile hydrocarbon, tolen, C]0II16. Old 
hard balsam of tolu is a convenient source of cinnamic acid, which is 
extracted by the same process as that by which benzoic acid may be 
obtained from benzoin—namely, ebullition with alkali, filtration, and 
precipitation by hydrochloric acid. 4. Storax (Styrax, U. S. P.) is 
an oleo-resin obtained from the Liquidambar orientate. It contains 
a volatile oil termed styrol cinnamene or cinnamol (P8H8)—which 
possibly (Berthelot) is condensed acetylene, 4C2112—cinnamic acid, 
stvracin or cinnamate of cinnamyl (C9119C9II70.2), and a soft and a 
hard resin. Styrol differs from similar hydrocarbons in being con- 
verted into a polymeric solid termed metastyrol or draconyl on heat- 
ing to about 400° F. For medicinal use, storax (Styrax Prceparatus, 
1>. P.) is sometimes purified by solution in alcohol, filtration, and 
removal of the alcohol by distillation. 
Caoutchouc or India-rubber and Gutta-percha. 
Caoutchouc is the hardened juice of Hevea (Siphonia) brazili- 
ensis, Castilloa elastica, Urceola elastica, Ficus elastica, and other 
plants (Collins). Heated moderately with sulphur, it takes up 2 or 
3 per cent., and forms vulcanized India-rubber; at a higher tem- 
perature a hard, horny product, termed ebonite or vulcanite, results. 
Gutta-percha (U. S. P.) is the concrete drop or juice of the percha 
(Malay) tree, the Isonandra gutta, and of other sapotaceous plants. 
It is soluble in chloroform (Liquor Gutta-pei'cha, U. S. P.), benzol, 
and essential oils. White gutta-percha is obtained by precipitating 
a solution of the ordinary gutta-percha in chloroform by alcohol, 
washing the precipitate with alcohol, and finally boiling in water 
and moulding into the desired form while still hot. The official 
solution of Gutta-percha (Liquor Gutta-percha, B. P.) is made by 
digesting thin slices of gutta-percha in 12 parts by weight of chloro- 
form, and then “fining” by shaking with 1 part of carbonate of 
lead and setting aside till the fluid is clear. 
These two elastic substances, in the pure state, are hydrocarbons 
(xC5II4), usually slightly oxidized. 
QUESTIONS AND EXERCISES. 
855. IIow do rosins occur in nature? Distinguish between resins 484 
CORORING-M ATTERS. 
and camphors. Mention the points of difference of resins, oleo-resins, 
gum-resins, and balsams. 
856. Name the source and chief constituents of common Resin or 
Rosin. 
857. Enumerate some official articles of which the active constitu- 
ents are resins. 
858. Give the chief distinguishing characters of Burgundy Pitch. 
859. What is the average proportion of oil and of resin in the so- 
called Balsam of Copaiva? 
860. Explain the effect of carbonate of magnesium, magnesia, and 
lime on copaiva. 
861. State the nature of Wood-tar. 
862. Why do Ammoniacum, Asafoctida, Gamboge, Galbanum, 
Myrrh, and similar substances give an emulsion by mere trituration 
with water? 
863. In what respect does Benzoin differ from the Balsams of 
Peru, Tolu, and Storax? 
864. What is the chemical nature of India-rubber and Gutta- 
percha ? 
865. IIow is India-rubber vulcanized and converted into ebonite 
or vulcanitet 
COLORING-MATTE RS. 
The animal, vegetable, and mineral kingdoms abound in sub- 
stances or pigments which powerfully decompose light, absorbing 
certain of its constituent colors and reflecting some others. Thus, 
for example, most leaves contain a body termed chlorophyll, which 
has the property of absorbing red light and reflecting green ; these 
reflected rays, entering the eye of an observer and striking on the 
retina (the expanded extremity of the optic nerve), always commu- 
nicate the same impression to the brain ; in popular language, the 
leaf is said to be green. Art has richly supplemented the number 
of such natural coloring-matters. 
Yellow.—1. Chrome yellow occurs in more than a dozen shades 
(see Lead, Chromate of). 2. Fustic or yellow-wood is the wood of 
the Rhus cotinus. 3. Gamboge (see Gamboge). 4. Ochre is met 
with of many tints, under the names of yellow ochre, gold yelloiv, 
gold earth or ochre, yelloiv sienna, Chinese yelloiv. It is chiefly a 
mixture of oxyhydrates of iron with alumina and lime. 5. Orpi- 
ment is a sulphide of arsenicum (As2S3). 6. Persian berries or 
Avignon grains contain a yellow principle termed rhamnin and 
other crystalline bodies. They are the product of the Rhamnus 
infectorius. 7. Purree or Indian yellow is said by Stenhouse to 
owe its color to purrate or euxanthate of magnesium (MgCt2lI.i4022). 
8. Quercitron is the bark of Quercus tinctoria or Black Oak. It 
contains the yellow glucoside, quercitrin (C18II]8O10,II.2O). 9. Rhu- 
barb (see Chrysophanic Acid, p. 335). 10. Saffron (Crocus, U. S. 
P.), the dried stigma and part of the style of Crocus sativus, yields 
saffranin or polychroite, an orange-red glucoside, which by the COLORING-MATTERS. 
485 
action of dilute acids and by other means breaks up, as shown in 
the following equation, yielding red crocin (Weiss):— 
c«nB0o18 + h2o = 2(C16H1806) + c10h14o + cBn12ofi 
Polychroite. Water. Crociu. Vol. oil of saffron. Sugar. 
11. Turmeric, the rhizome of Curcuma longa, owes its yellow color 
to curcumin, a resinous matter, the formula of which is said by 
Daube to be C,0lI10O3, and by Iwanof C1BII1604. Jackson and Menke 
state that curcumin is an acid, and that its formula is ii2cuii,A- 
Possibly two yellow pigments are present. 12. Weld (Reseda Inter 
ola) contains a durable yellow matter termed luteolin (C20lI,4O3). 
13. Picric or carbazotic acid (p. 450) is a very powerful yellow dye. 
14. Dried and powdered carrots yield to bisulphide of carbon a 
yellow coloring-matter, “ carrotin,” which is obtained on evapor- 
ating the solvent. It is said to be used in coloring butter. 
Red.—1. Alkanet, the root of Alkanna tinctoria, Tausch, Anchusa 
iinctoria, Desf., yields anchusin (C35II40O8), a resinoid matter solu- 
ble in oils and fats. 2. Annato, Arnatto, or Arnotto, a paste pre- 
pared from the seeds of Bixa orellana, contains bixin, an orange- 
red, and orellin, a yellow principle. 8. Brazil-wood (Ccesalpinia 
brasiliensis) furnishes brezilin, the basis of several lakes. Sapan- 
wood and Cam-wood probably contain the same substance. 4. Cin- 
nabar, Chinese red, Vermilion, or Paris red is mercuric sulphide. 
5. Chrome red is an oxychromate of lead. 6. Cochineal (p. 334). 
7. Madder, the root of Rubia tinctorum, powdered and treated 
with sulphuric acid and acidulated water to effect the removal of 
earthy and other inert matters, furnishes a residual powder termed 
garancin. Garancin yields to pure water alizarin (0UII]804,3II20), 
the red, neutral, crystallizable coloring-matter of madder. Alizarin 
does not exist ready formed in the plant, but is derived by fermen- 
tation from rubian, a yellowish resinoid substance. Alizarin is now 
produced artificially from anthracene, one of the solid constituents 
of coal-tar. 8. Mulberry-juice (Mori Succus, B. P.) contains a violet- 
red coloring-matter which has not been chemically examined. 9. 
Red lead (p. 208). 10. Red oxide of iron, of shades varying from 
light to brown-red, is found native. The common names of it are 
Armenian bole, Berlin red, colcothar, English red, red ochre, burnt 
ochre, red earth, terra di sienna, mineral purple, stone red, and 
Indian red. 11. Red Sanders-wood or Red Sandal-wood (Santalum 
rubrum or Red Saunders, U. S. P.), the billets and chips of Ptero- 
carpus santalinus, owes its color to santalin (C14II1204), a crystalline 
resinoid matter. 12. Red Poppy Petals (Rhcedos Petula, B. P.), 
from the Papaver rhaeas, contain a red coloring-principle which has 
not yet been isolated in a state of purity. The author has sought 
for morphine in large quantities of the petals, but could not find a 
trace of that alkaloid. 13. Red Rose Petals (Rosa Gallica, U. S. P.), 
and those of the Cabbage Rose (Rosa Centifolia, U. S. P.), also yield 
a red substance, which has not been analyzed. 14. Safflower, Dyerrs 
Saffron, or Bastard Saffron, the florets of Carthamus tinctorius, 
contains an unimportant yellow dye and *5 per cent, carthamin 
(C14Hlg07), an uncrystallizable red dye, the pigment of the old pink 486 
COLOTlING-MATTEItS. 
saucers. Oarthamin seems to possess acid characters, and (like 
silicic acid arid other substances) to be soluble in water for a certain 
time after liberation from its alkaline solution ; for fabrics are dyed 
with safflower by immersion in a bath made of an infusion in dilute 
alkali neutralized by citric acid immediately before use, the cartha- 
min probably penetrating the cells and vessels of the fibres in a 
soluble form, there becoming insoluble and imprisoned, and thus 
giving permanent color to the wool, silk, or other material. Mixed 
with French chalk, carthamin is used as a cosmetic under the name 
of vegetable rouge—carmine being animal rouge and red oxide of iron 
mineral rouge. 15. Lac-dye is a cheap form of cochineal, and is also 
yielded by the species of Coccus, whose resinous excretion consti- 
tutes lac (stick-lac, seed-lac, or shell-lac, according to its condition as 
gathered off the twigs on which it is deposited, or as roughly sep- 
arated from impurities in seed-like powder or lumps, or as melted 
and squeezed through bags into shell-like pieces). 10. Logwood 
(Hcematoxylon, U. S. P.) contains a yellow substance, hcematoxylin 
(C16II1406,H20 or 3II20), which under the influence of air and alkali 
assumes an intense red color. Under the influence of ammonia and 
air it yields greenish-violet iridescent scales of hcematin (ClfiII,206,- 
3II20). 17. Red enamel colors, for glass-staining and ceramic oper- 
ations, are produced either by cuprous silicate or purple of Cassius 
(p. 243). 
Blue.—1. Cobalt oxide, precipitated in combination or admixture 
with alumina or phosphate of calcium, forms Thenard's blue, cobalt 
blue, Hoffner's blue, and cobaltic ultramarine. 2. Smalt, Saxony 
blue or King's blue, is rough cobalt glass in fine powder (p. 230). 
3. Copper blue, mountain blue, and English or Hambro' blue are 
carbonates or oxycarbonates of copper. 4. Indigo (p. 287). 5. 
Litmus, lichen blue, turnsole, orchil or archil, and cudbear are 
products of the action of air and alkalies on certain colorless prin- 
ciples, as orcin (C7II802), derived from different species of lichen, 
Roccella, Variolaria, and Lecanora. 6. Prussian blue (p. 338) and 
Turnbull's blue (p. 339), the ferro- and ferridcyanides of iron, are 
met with under the names of Erlangen, Louisa, Saxon, Paris, or 
Berlin blue. 7. Ultramarine is made on a large scale by roasting a 
mixture of fine white clay, carbonate of sodium, sulphur, and char- 
coal. Its constitution is not well made out. Acids decompose it, 
sulphuretted hydrogen escaping. 
Green.—1. Cupro-arsenical green pigments (p. 173). 2. Chlo- 
rophyll, Leaf green, or Chromule. (A method of extracting chlo- 
rophyll is given under “Extracts,” vide Index.) It is resinoid, sol- 
uble in alcohol and ether, insoluble in water, and, according to 
Fremy, consists of a blue substance, phyllocyanin (C34II68N4017 ?), 
and a yellow, phylloxanthin ; the yellow tints in fading autumnal 
leaves, he says, ai*e due to the latter principle, the former being the 
first to fade. Chlorophyll would probably well repay extended in- 
vestigation. 3. Sap-green, buckthorn-, vegetable-, or bladder-green is 
obtained by evaporating to dryness a mixture of lime and the juice 
(Rhamni Succus, B. P.) of the berries of the Buckthorn (Rhamnus COLORING- M ATT E RS. 
487 
catharticus). It is soluble in water, slightly in alcohol, and insol- 
uble in ether and oils. 4. Green ultramarine is made by a process 
similar to that of blue ultramarine. 5. Mixtures of blue and yellow 
pigments and dyes are common sources of green colors. 6. Glass 
and earthenware are colored green by oxide of chromium and black 
oxide of copper. 
Brown.—1. Umber, Sienna, or Chestnut brown is found native. 
By heat it is darkened in tint, and is then known as burnt umber. 
It is a mixture of oxide of iron, silica, and alumina. 2. Sepia is a 
dried fluid from the ink-bag of cuttle-fishes (Sepiadce); by its ejec- 
tion into adjacent water the animal obtains opportunity of escape 
from enemies. 3. Catechu (p. 355) furnishes a brown coloring- 
matter. 
Black.—1. Black-lead (p. 30), boneblack (p. 110) or ivory-black, 
and lampblack, the latter a deposited soot from incomplete combus- 
tion of resin and tar, are varieties of carbon. 2. Burnt sugar or 
caramel (p. 415). 3. Indian ink is usually a dried mixture of fine 
lampblack and size or thin glue. 4. Black ink is essentially tan- 
nates and gallates of iron suspended in water containing a little 
gum in solution. 5. Printer's ink is well-boiled linseed or other oil 
mixed with good lampblack, vermilion, or other pigment. 6. Black 
dyes are of the same nature as ink. 7. The pigmentum nigrum of 
black feathers, such as those of the common rook, of dark hair, and 
probably also of the skin of the negro, seems to be due to the black 
substance which remains undissolved when black feathers are digested 
for some time in dilute sulphuric acid. It is said to have the formula 
C,8H16N208 (Ilodgkinson and Sorby). 
White Pigments.—1. Chalk or Whiting (p. 108). 2. French chalk, 
steatite, or soapstone, a silicate of magnesium. 3. Heavy white (p. 
101). 4. Pearl-white (p. 248). 5. Plaster of Paris (p. 113). (5. 
Starch (p. 401). 7. White-lead (p. 206). 8. Zinc-white (p. 131). 
9. Oxides of tin and zinc and phosphate of calcium are employed 
for giving a white opacity to glass. 
Aniline Colors.—Coal-tar Colors.—Within the last ten years 
nearly every shade of color seen in the animal and vegetable "king- 
doms has been successfully imitated by certain dyes and pigments 
primarily derived from a mineral, coal. Coal distilled for gas fur- 
nishes tar or gas-tar. Coal-tar contains some aniline, but especially 
it contains a liquid convertible into aniline—namely, benzol (CfilI3Il), 
first discovered by Faraday in compressed oil-gas. From aniline, by 
oxidation, Bunge obtained the violet color-reaction, the body pro- 
ducing which Perkin afterward studied and isolated, and manu- 
factured under the name of mauve. Aniline red (fuchsine, magenta, 
or rosaniline), aniline yellow, aniline green, aniline blue, and, in 
short, aniline dyes, lakes, and pigments of every hue of the rainbow, 
are now common articles of trade. Their application has revolution- 
ized the arts of the dyer and color-printer. The dyeing power of 
aniline colors may be used in testing for their presence in colored 
wines (claret, port, etc.). 488 
GENERAL QUALITATIVE ANALYSIS. 
QUESTIONS AND EXERCISES. 
866. Explain the production of color by various natural and arti- 
ficial pigments. 
867. Mentio'n the chief yellow coloring-matters, and describe their 
chemical nature. 
868. What is annatto? 
869. Name the colorific constituent of madder. Can it be made 
artificially ? 
870. State the source of Litmus. 
871. Distinguish between Prussian blue and Turnbull’s blue, and 
state how they are manufactured. 
872. How is blue ultramarine obtained? How is it affected by 
acids ? 
873. Describe the chemical nature of the coloring-principle of 
green leaves. 
874. By what agents is glass colored green? 
875. AVhence is sepia obtained? 
876. Describe the chemistry of black ink. 
877. Write a few sentences on aniline colors. 
QUALITATIVE ANALYSIS OF SUBSTANCES 
HAVING UNKNOWN PROPERTIES. 
Substances are presented to the analyst in one of the three 
forms in which all matter exists—namely, solid, liquid, or 
gaseous—and they may contain animal or vegetable as well as 
mineral matter. 
The method of analysis in the case of solid mineral bodies 
has been described on pp. 367 to 374. 
Solid animal or vegetable substances (or mixtures of these 
with mineral bodies) may be indefinite and beyond the grasp of 
chemistry, or definite and quite within the range of proximate 
qualitative organic analysis. The presence of such substances 
is indicated in the preliminary examination of a solid (pp. 367 
to 369) by charring and other characters. If no charring oc- 
curs and no volatile liquid is expelled by heat, the absence of 
such matter is indicated. But if organic matter is present, an 
endeavor is made to ascertain its precise character. The ana- 
lyst’s knowledge of the history of the substance or the cir- 
cumstances under which it conies into his hands will probably 
afford a clue to its nature and enable him to search directly 
for its proximate constituents. If no such information is at 
hand, the action of solvents may be employed, as likely to af- 
ford indication of the general, if not of the precise, nature of 
the substance. Water, alcohol, ether, chloroform, bisulphide 
of carbon, each both hot and cold, may in turn be agitated with 489 
GENERAL QUALITATIVE ANALYSIS. 
the substance, the mixture filtered, a portion of the filtrate 
evaporated, at first partially, setting the product aside, and 
afterward to dryness, and any deposit or residue examined 
with and without the aid of a microscope. Other portions of 
the filtrate may he treated with acids, alkalies, and solutions of 
such metallic salts as are commonly used as group-tests for 
acidulous radicals (p. 3G4). The action of alkalies, as well as 
acids, weak and strong, hot and cold, may also be tried on the 
solid substance itself, and colors, odors, and, in short, any effect 
whatever, duly noted. A portion of the substance should also 
be burnt in an open porcelain crucible until no carbon remains, 
and the ash, if any, examined; its amount and nature may 
afford information leading to the identification of the sub- 
stance. 
The foregoing experiments having been carefully performed 
and all results entered in the note-book, a little reflection will 
possibly lead to the recognition, or may suggest further direct 
experiments or confirmatory tests, or will, at least, have pointed 
to the absence of 90 or 95 per cent., of all possible substances, 
and thus have restricted the area of inquiry to narrow limits. 
The success attainable in qualitative proximate organic analysis 
by the medical or pharmaceutical student will of course largely 
depend on the thoroughness with which the operator has prose- 
cuted his study of practical chemistry generally, but it also 
will be considerably affected by the extent to which he has 
cultivated the art of observation, and the opportunities he has 
had of acquiring a knowledge of the appearances, uses, and 
common properties of definite chemical substances and of ar- 
ticles of food, drink, and medicine. The most successful of 
several good analysts will be the one who has most common 
sense and most experience. 
The pharmaceutical student, who has probably already had 
some years of experience in pharmacy, occupies an unusually 
favorable position for prosecuting the proximate analysis of 
organic and inorganic substances, or, at all events, of that large 
proportion of such bodies met with in the domain of hygiene 
and pharmacy. Many substances he will identify at sight or 
by aid of a lens, or after applying some simple physical or 
chemical test. Nor should he find much difficulty, after reach- 
ing the present point of practical study, in deciding whether 
the solid substance under examination belongs to the class of 
organic acids, organic salts of metallic radicals, alkaloids, salts 
of alkaloids, amylaceous matter, gums, saccharine substances, 
glucosides, albumenoid- matters, fats, soaps, resins, coloring-mat- 
ters, etc. For instance, the pharmaceutical student will find 490 
GENERAL QUALITATIVE ANALYSIS. 
less difficulty than the general student in successfully analyzing 
a substance occurring in “ scales,” because he has experience 
of the appearances of compounds commonly produced in that 
form, and because, even if the appearance is new to him, he 
knows what kind of substances most readily lend themselves 
to production in that form. While the general student is test- 
ing generally and proceeding cautiously, or searching for gen- 
eral information in books of reference, the pharmaceutical or 
medical student has incinerated some of the material, noticed 
whether or not the ash is red (iron) and strongly alkaline 
(potassium), treated more of the material with an alkali (for 
ammonium), added excess of ammonia, and examined the pre- 
cipitate (for cinchonine or quinine), or shaken up the alkaline 
liquid successively with ether and chloroform, and tested the 
residue of these decanted and evaporated solvents (quinine, 
beberine, strychnine), and examined the aqueous solution of the 
material or one of the filtered alkaline liquids in the usual 
way for acidulous radicals (citric, tartaric, sulphuric, hypo- 
phosphorous) ; or he has modified his methods to include 
search for some “ scale preparation ” which his special know- 
ledge tells him has been newly introduced to, or is rare in, 
pharmacy. 
In the case of liquids the solvents as well a£ the dissolved 
matters claim attention. A few drops are evaporated to dry- 
ness on platinum foil to ascertain if solid matter of any kind is 
present; the liquid is tested by red and blue litmus-paper to 
ascertain if free alkalies, free acids, or neither, are present; a 
few drops are heated in a test-tube and the odor of any vapor 
noticed, a piece of glass tubing bent to a right angle being, if 
necessary, adapted to the test-tube by a cork, and some of the 
distilled liquid collected and examined ; finally, the usual group- 
reagents for the several basylous and acidulous radicals are 
consecutively applied. 
Proceeding in this way, the student, who has already had 
some experience in pharmacy, will not be likely to overlook 
such solvents as water, acids, alkalies, alcohol, glycerin, ether, 
chloroform, benzol, fixed oils, and essential oils, or to miss the 
substances which these menstrua may hold in solution. He 
will probably also recognize such liquids as carbolic acid, formic 
acid, lactic acid, methylic alcohol, aldehyd, aniline, nitrobenzol. 
He must not, however, suppose that he will always be able to 
qualitatively analyze, say, a bottle of medicine, for the various 
infusions, decoctions, tinctures, wines, syrups, liniments, con- 
fections, extracts, pill-masses, and powders contain vegetable 
matters, most of which at present are quite beyond the reach of GENERAL QUALITATIVE ANALYSIS. 
491 
the analyst. Neither the highest skill in analysis, nor the 
largest amount of experience concerning the odor, appearance, 
taste, and uses of drugs, is sufficient for the detection of all 
these vegetable matters. Skill and experience combined, how- 
ever, will do much, and in most cases even so difficult a task as 
the one just mentioned be accomplished with reasonable success. 
Obviously, qualitative analysis alone will not enable the exper- 
imenter to produce a mixture of substances similar to that 
analyzed; to this end recourse must be had to quantitative 
analysis, a subject reserved for subsequent consideration. 
Natural fluids, as “ Milk ” and “ Urine ” (vide Index), admit 
of special analytical treatment. 
Gas-analysis, or Eudiometry (from eudca, eudia, calm air, 
and fiirpov, metron, a measure, in allusion to the eudiometer, an 
instrument used in measuring the proportion and, as the early 
chemists thought, the salubrity of the gases of the air), is a 
branch of experimental investigation, chiefly of a quantitative 
character, concerning which information must be sought in 
other treatises. The analysis of atmospheric air from various 
localities, coal-gas and gases obtained in chemical researches, 
involves operations which are scarcely within the sphere of 
Chemistry applied to Medicine. Beyond the recognition, there- 
fore, of oxygen, hydrogen, nitrogen, carbonic, sulphurous, and 
hydrosulphuric acid gases, the experimental considerations of 
the chemistry of gaseous bodies may be omitted. Their study, 
however, should not be neglected, as existing conceptions of 
the constitution of chemical substances are largely dependent 
on the observed relations of the volumes of gaseous compounds 
to their elements. (See previous paragraphs, pp. 36 to 43, 54 
to 58, and 155.) The best single work on this latter part of the 
subject is a small book by Hofmann, Introduction to Modern 
Chemistry. 
Epecfrtd Analysis.—It may be as well to state here that the 
preliminary and final examinations of minute quantities of solid 
matter may, in certain cases, profitably include their exposure 
to a temperature at which they emit light, the flame being 
physically analyzed by a spectroscope. A spectroscope con- 
sists essentially of a prism to decompose a ray of light into its 
constituent colors, with tubes and lenses to collect and trans- 
mit the ray or rays to the eye of an observer. The material 
to be examined is placed on the end of a platinum wire, which 
is then brought within the edge of a spirit-lamp or other smoke- 
less flame; volatilization, attended usually in the case of a 
compound by decomposition, at once occurs, and the whole 
flame is tinged with a characteristic hue. A flat ribbon of rays 492 
CHEMICAL TOXICOLOGY. 
is next cut off by bringing near to the flame a brass tube the 
cap of which is pierced by a narrow slit. At the other end of 
the tube, at focal distance for parallel rays, is a lens through 
which the ribbon of light passes to a prism ; the prism decom- 
poses the ribbon, spreading out its constituent colors like a 
partially-opened fan, and the colored beam or spectrum thus 
produced is then examined by help of a telescope attached by 
a movable joint to the stand which carries the prism and 
object-tube. Sodium compounds under these circumstances 
give yellow light only, indicated by a double band of light in 
a position corresponding to a portion of the yellow part of an 
ordinary solar spectrum. The potassium spectrum is mainly 
composed of a red and violet band; lithium, a crimson, and at 
very high temperatures a blue band. Most of the other ele- 
ments give equally characteristic spectra. 
By aid of a combined microscope and spectroscope (micro- 
spectroscope) the color of colored fluids can be analyzed. 
CHEMICAL TOXICOLOGY. 
In cases of criminal and accidental poisoning the substances 
presented to the chemical analyst for examination are usually 
articles of food, medicines, vomited matters, or the liver, 
kidney, intestines, stomach and contents, removed in course of 
post-mortem examination. In these cases some special opera- 
tions are necessary before the poison can be isolated in a state 
of sufficient purity for the application of the usual tests ; for 
in most instances the large quantity of animal and vegetable— 
or, in one word, organic—matter present prevents or masks the 
characteristic reactions on which the tests are founded. These 
operations will now be described ;* they form the chemical 
part of the subject of Toxicology taxi con, poison, and 
/n'tyoq, locjos, discourse). 
Substances occurring in the form of an apparently definite 
salt or unmixed with organic matter need no special treatment; 
they are analyzed by the ordinary methods already given, at- 
tention being restricted to poisonous compounds only. 
* Materials for these experiments are readily obtained for educa- 
tional purposes by dissolving the poison in infusions of tea or coffee, in 
porter, or in water to which some mucilage of starch, or linseed-meal, 
pieces of bread, potato, and fat have been added. chemical toxicology. 
493 
Examination op an Organic Mixture suspected to con- 
tain Mercury, Arsenicum, Antimony, Lead, Copper, 
or Zinc; Sulphuric Acid, Nitric Acid, Hydrochloric 
Acid, Oxalic Acid, or Hydrocyanic Acid ; Caustic 
Alkalies; Phosphorus; Strychnine, Morphine, or 
other Poisonous Alkaloids. 
Prelim inary Examination. 
Odor, Appearance, Taste.—Smell the mixture, with the view 
of ascertaining the presence or absence of any notable quantity 
of free hydrocyanic acid. Look carefully for any small solid 
particles, such as arsenic, corrosive sublimate, or verdigris, and 
for any appearance which may be regarded as abnormal, any 
character unusual to the coffee, tea, beer, medicine, vomit, 
coats of stomach, kidney, liver, or other organ, tissue, or solid 
matter under examination. 
Poisonous Quantity of Acid.—Add to a small portion some 
solution of carbonate of sodium, with the view of ascertaining 
by strong effervescence the presence of any large, poisonous 
quantity of sulphuric, nitric, or hydrochloric acid (p. 495). 
Poisonous Quantity of Alkali.—If so excessively alkaline as 
to require the addition of a very large quantity of acid before 
neutralization is effected, a noxious quantity of a corrosive or 
caustic alkali is present. Whether soda or potash, is ascertained 
by the usual tests. 
Special instructions may induce the operator to suspect the 
presence of one particular poison. Direct examination for the 
latter may then be made, either at once if the substance has 
an aqueous character, or when filtration or treatment with 
warm hydrochloric or acetic acid has afforded a more or less 
colorless liquid. 
Fluids.—A vomit or the contents of a stomach, if set aside 
in a long narrow vessel (test-glass or ale-glass), or, better, ex- 
posed on a filter during a night, will often yield a more or less 
clear limpid portion at the bottom or top of the solid matter. 
This fluid (separated by a pipette or otherwise) will sometimes 
respond to tests without further preparation, and always re- 
quires less preparatory treatment than a semi-solid mixture. 
If none passes through a filter, a portion often collects in the 
upper part. 
General Procedure.—If the preliminary examination does 
not indicate the method to be pursued, proceed as follows, 
treating a portion (not more than one-fourth) of the mixture 
for the poisonous metals, another for the acids, and a third for 494 
CHEMICAL TOXICOLOGY. 
alkaloids, reserving the remainder for any special experiments 
which may suggest themselves in the course of analysis:— 
Examination for Mercury, Arsenicum, Antimony, Laid, 
Copper, Zinc. 
If a liquid, acidulate with hydrochloric acid and boil for a 
short time. If solid or semi-solid, cut up the matter into small 
pieces, add enough water to form a liquid mixture, stir in 10 or 
20 per cent, of ordinary liquid hydrochloric acid, and boil until, 
from partial aggregation and solution of the solid matter, filtra- 
tion can be easily effected. 
Heat a portion of the clear liquid with a thin piece of bright 
pure copper or copper gauze about an inch long and a quarter 
of an inch broad for about ten or twenty minutes; metallic 
mercury, arsenicum, or antimony will be deposited on the copper, 
darkening it considerably in color. Pour off the liquid from 
the copper, carefully rinse the latter with a little cold water, 
dry the piece of metal by holding it over or near a flame (using 
fingers, not tongs, or it may become sufficiently hot for loss of 
mercury or arsenicum to occur by volatilization), introduce it 
into a narrow test-tube or piece of glass tubing closed at -one 
end, and heat the bottom of the tube in a flame, holding it 
horizontally, that the upper part of the tube may be kept cool, 
and partially closing the mouth with the finger to prevent 
escape of vapor. Under these circumstances any mercury will 
volatilize from the copper and condense on the cool part of the 
tube in a ring or patch of white sublimate, readily aggregating 
into visible globules on being pressed by the side of a thin 
glass rod inserted into the tube; arsenicum will volatilize from 
the copper, and, absorbing oxygen from the air in the tube, 
condense on the cool part of the glass in a ring or patch of 
white sublimate of arsenic (gray, or even darker if much 
arsenicum as well as arsenic be present), not running into 
globules when rubbed, but occurring in small crystals, the 
characteristic octahedral form of which is readily seen by aid 
of a good hand-lens or the lower part of a microscope; anti- 
mony volatilizes from the copper if strongly heated, and, ab- 
sorbing oxygen, immediately condenses as a slight white deposit 
close to the metal. 
Confirmatory Tests.—1. Nothing short of the production of glob- 
ules should be accepted as evidence of the presence of mercury. It 
will usually have existed as corrosive sublimate. 
2. To confirm indications of the presence of arsenicum, a portion 
of the acid liquid may be subjected to the hydrogen tests (pp. 169, MINERAL ACIDS, OXALIC ACID, ETC. 
170), or the tube containing the white crystalline arsenic may be 
broken, and the part on which the sublimate occurs boiled for some 
time in water, and the hydrosulphuric-acid, ammonio-nitrate-of-silver, 
and ammonio-sulphate-of-copper tests (pp. 172, 174) applied to the 
aqueous solution. 
3. For antimony a portion of the acid liquid must always be intro- 
duced into the hydrogen apparatus with the usual precautions. ( Vide 
p. 184.) 
Note.—Before finally concluding that arsenicum is absent from a 
fluid the latter should be warmed with a little sulphurous acid, and 
ordinary tests then again applied, for arsenic acid and other arse- 
niates are not readily affected by the usual reagents for arsenicum. 
For lead or copper, pass hydrosulphuric acid gas through 
the clear acid liquid for some time, warming the liquid if no 
precipitate is produced, or diluting and partially neutralizing 
the acid by ammonia if much acid has been added. Collect on 
a filter any black precipitate that may have formed; wash, 
dissolve in a few drops of aqua regia, dilute, and apply the 
tests, such as ammonia for copper, sulphuric acid for lead, and 
any other of the ordinary reagents (pp. 189, 210). 
Copper may often he at once detected in a small quantity of acid- 
ulated liquid by immersing the point of a penknife or a piece of 
bright iron wire—a deposit of copper, in its characteristic color, 
quickly or slowly appearing, according to the amount present (p. 
189). 
Zinc.—To the acid liquid through which sulphuretted hydro- 
gen has been passed, add excess of ammonia (or to the original 
acid fluid add excess of ammonia and then sulphydrate of am- 
monium) ; a precipitate falls which may contain alumina, phos- 
phates, and zinc ; it is usually blackish from the presence of 
sulphide of iron. Collect the precipitate on a filter, wash, dis- 
solve in a little hydrochloric acid, add a few drops of nitric 
acid, boil, pour in excess of ammonia, filter, and test the filtrate 
with sulphydrate of ammonium : a white precipitate indicates 
zinc. 
Examination for Mineral Acids, Oxalic Acid, or 
Hydrocyanic Acid. 
To detect Hydrochloric, Nitric, or Sulphuric And in any 
liquid containing organic matter, dilute with water and apply 
to small portions the usual tests for each acid, disregarding in- 
dications of small quantities. ( Vide pp. 264, 286, 3U7.) 
Excessive sourness, copious evolution of carbonic acid gas on the 
addition of carbonate of sodium, and abundant evidence of acid on 
applying the various tests to small portions of the fluid presented for 496 
CH EM I CAL, TOXICOLOGY. 
analysis, collectively form sufficient evidence of the occurrence of a 
poisonous amount of either of the three common mineral acids. 
Small quantities of the hydrochloric, nitric, and sulphuric radicals 
occurring as metallic salts or acids are common normal constituents 
of food, hence the direction to disregard insignificant indications. If 
the fluid under examination he a vomit or the contents of a stomach, 
and an antidote has been administered, free acid will not be found, 
but, instead, a large amount of corresponding salt. 
For oxalic acid, filter or strain a portion of the liquid, if 
not already clear, and add solution of acetate of lead so long 
as a precipitate occurs; collect the precipitate, which is partly 
oxalate of lead, on a filter, wash, transfer it to a test-tube or 
test-glass, add a little water, and pass hydrosulphuric gas 
through the mixture for a short time; the lead is thus con- 
verted into the insoluble form of sulphide, while oxalic acid is 
set free in the solution. Filter, boil to get rid of hydrosul- 
phuric gas, and apply the usual tests for oxalic acid (see p. 
314) to the clear filtrate. 
The contents of a stomach containing oxalic acid are often 
of a dark-brown color with a tinge of green (altered blood and 
mucus), and the viscid mixture generally, though slowly, af- 
fords some clear, limpid, almost colorless liquid by filtration or 
standing. 
For hydrocyanic, acid the three chief tests may be applied 
at once to the liquid or semi-liquid organic mixture, whether 
it has an'odor of hydrocyanic acid or not. First: Half fill a 
small porcelain crucible with the material, add eight or ten 
drops of strong sulphuric acid, stir gently with a glass rod, 
and invert over the mouth of the crucible a watch-glass moist- 
ened with a small drop of solution of nitrate of silver ; a white 
film on the silver solution is probably cyanide of silver, formed 
by the action of the gaseous hydrocyanic acid on the nitrate of 
silver. Second: Prepare a small quantity of the organic mix- 
ture as before, slightly moistening the centre of the watch- 
glass with solution of potash; here, again, the heat generated 
by the action of the strong acid is sufficient to volatilize some 
of the hydrocyanic acid, which, reacting on the potash, forms 
cyanide of potassium. On removing the watch-glass and stir- 
ring into it successively solution of a ferrous salt, a ferric salt, 
and hydrochloric acid, flocks of Prussian blue are produced if 
hydrocyanic acid is present. Third: Proceed as before, moist- 
ening the watch-glass with sulphydrate of ammonium; after 
exposure to the hydrocyanic gas for five or ten minutes add a 
drop of solution of ammonia, evaporate to dryness at a low 
temperature, and add a drop of hydrochloric acid and of solu- STRYCHNINE AND MORPHINE. 
497 
tion of perchloride of iron ; a blood-red color, due to sulpho- 
cyanate of iron, is produced if cyanogen is present. 
If the above reactions are not well marked, the organic mixture 
may be carefully and slowly distilled in a small retort, the neck of 
which passes into a bottle and dips beneath the surface of a little 
water at the bottom of the bottle, and the reagents then applied to 
separate portions of the distillate. 
The examination of organic mixtures for hydrocyanic acid must 
be made without delay, as the poison soon begins to decompose, and 
in a day or two is usually destroyed. 
Examination for Phosphorus. 
A paste containing phosphorus is commonly employed for destroy- 
ing vermin. In cases of poisoning the phosphorus is commonly in 
sufficient quantity to be recognized by its characteristic unpleasant 
smell. A stomach in which it occurs not unfrequently exhibits 
slight luminosity if opened in a dark room. When the phosphorus 
is too small in quantity or too much diffused to afford this appear- 
ance, a portion of the material is placed in a flask, water acidulated 
by sulphuric acid added, a long wride glass tube fitted to the neck of 
the flask by a cork, and the mixture gently boiled. If phosphorus is 
present (even 1 part in 2,000,000, according to De Yrij) the top of 
the column of steam as it condenses in the tube will appear dis- 
tinctly phosphorescent when viewed in a dark room. From its 
liability to oxidation, phosphorus cannot be detected after much 
exposure of an organic mixture to air. 
Examination for Strychnine and Morphine. 
Strychnine.—If solid or semi-solid, digest the matter with 
water and about 10 per cent, of hydrochloric acid till fluid ; 
filter, evaporate to dryness over a water-bath. If the organic 
mixture is already liquid, it is simply acidulated with hydro- 
chloric acid and evaporated to dryness. The acid residue is 
next treated with spirit of wine as long as anything is dissolved, 
the filtered tincture evaporated to dryness over the water-bath, 
and the residue digested in water and filtered. This slightly 
acid aqueous solution must now be rendered alkaline by ammo- 
nia, and well shaken in a bottle or long tube with about half 
an ounce of chloroform, and set by till the chloroform has sub- 
sided. The chloroform (which contains the strychnine) is then 
removed by a pipette, the presence of any aqueous liquid being 
carefully avoided, and evaporated to dryness in a small basin 
over a water-bath, the residue moistened with concentrated sul- 
phuric acid, and the basin kept over the water-bath for several 
hours. (It is highly important that the sulphuric acid used in 
this operation should be free from nitrous compounds. Test 498 
CHEMICAL TOXICOLOGY. 
the acid, therefore, by adding powdered sulphate of iron, which 
becomes pink if nitrous bodies are present. If these are found, 
the acid should be purified by strongly heating with sulphate 
of ammonium, 70 or 80 grains to a pint.) The charred mate- 
rial is exhausted with water, filtered, excess of ammonia added, 
the filtrate shaken with about a quarter of an ounce of chloro- 
form, the mixture set aside for the chloroform to separate, and 
the chloroform again removed. If, on evaporating a small 
portion of this chloroform solution to dryness, adding a drop 
of sulphuric acid to the residue, and warming, any darkening 
in color or charring takes place, the strychnine is not suffi- 
ciently pure for chemical detection ; in that case the rest of 
the chloroform must be removed by evaporation and the resi- 
due redigested in warm sulphuric acid for two or three hours. 
Dilution, neutralization of acid by ammonia, and agitation with 
chloroform are again practised, and the residue of a small por- 
tion of the chloroform solution once more tested with sulphuric 
acid. If charring still occurs, the treatment must be repeated 
a third time. Finally, a part of the chloroform solution is 
taken up by a pipette, and, drop after drop, evaporated on one 
spot of a porcelain crucible-lid until a fairly distinct dry resi- 
due is obtained. A drop of sulphuric acid is placed on the 
spot, another drop placed near, a minute fragment of red chro- 
mate of potassium placed in the second drop, and, when the 
acid has become tinged with the chromate, one drop drawn 
across the other; the characteristic evanescent purple color is 
then seen if strychnine is present. Other tests (vide p. 389) 
may be applied to similar spots. 
This is Girdwood and Rogers’s method for the detection of strych- 
nine when mixed with organic matter. It is tedious, but trustworthy, 
and, though apparently complicated, very simple in principle; thus, 
strychnine is soluble in acidulated water or alcohol or in chloroform, 
readily removed from an alkaline liquid by agitation with chloroform, 
and not charred or otherwise attacked when heated to 212° F. with 
sulphuric acid: much of the organic matter of the food is insoluble 
in water; of that soluble in water, much is insoluble in alcohol; 
and of that soluble in both menstrua, all is charred and destroyed 
by warm sulphuric acid in a shorter or longer time. 
Morphine, and the, Meconic Acid with which it, is Associated in 
Opium.—To the liquid or the semi-fluid mixture warmed for 
some time in a small quantity of acetic acid, filtered and con- 
centrated if necessary, add solution of acetate of lead until 
no further precipitate is produced. Filter and examine the 
precipitate for meconic acid, reserving the filtrate for the de- 
tection of morphine. STRYCHNINE AND MORPHINE. 
The Precipitate.—Wash the precipitate (meconate of lead, 
etc.) with water, place it in a test-tube or test-glass with a 
small quantity of water, pass hydrosulphuric acid gas through 
the mixture for a short time, filter, slightly warm in a small 
basin, well stirring to promote removal of excess of the gas, 
and add a drop of neutral solution of perchloride of iron; a 
red color, due to the formation of meconate of iron, is produced 
if meconic acid is present. This color is not destroyed on boil- 
ing the liquid, as is the case with ferric acetate, nor is it 
bleached by solution of corrosive sublimate, thus distinguish- 
ing it from the ferric sulphocyanate. It is discharged by 
hydrochloric acid. 
The Filtrate.—The solution from which meconic acid has 
been removed by acetate of lead is evaporated to a small bulk 
over a water-bath, excess of carbonate of potassium added, and 
evaporation continued to dryness. The residue is then treated 
with alcohol, which dissolves the morphine. The alcoholic 
solution evaporated similarly may leave the morphine sufficient- 
ly pure for the application of the usual tests {vide p. 381) to 
small portions of the residue. If no reaction is obtained, add 
a drop of sulphuric acid and a little water to the residue and 
shake with ether, in which the salt of morphine is insoluble. 
The treatment with ether may be repeated until nothing more 
is removed, the acid aqueous liquid saturated with carbonate 
of potassium, the mixture evaporated to dryness, the residue 
digested in alcohol, filtered, and portions of the alcoholic liquid 
evaporated to obtain spots of morphine for the application of 
the ordinary tests. 
If much organic matter is believed to remain in the filtrate 
after the acetate-of-lead treatment, or if a considerable excess 
of acetate of lead has been employed, the filtered liquid should 
be subjected to a current of sulphuretted hydrogen until no 
more sulphide of lead is precipitated, the mixture filtered, and 
the filtrate, with the washings from the sulphide of lead, evapor- 
ated to a small bulk, excess of carbonate of potassium added, 
the whole well mixed and agitated with twice or thrice its bulk 
of a mixture of ether and acetic ether (ether alone might not 
dissolve the morphine). On standing, the ethereal liquid rises 
to the surface; it is carefully removed, evaporated to dryness, 
and the residue tested or further purified in the manner de- 
scribed in the preceding paragraph. 
The examination for morphine must be conducted with great care, 
and with as large a quantity of material as can be spared, for its 
isolation from other organic matter is an operation of considerable 
difficulty, especially when only a minute proportion of alkaloid is 500 
CHEMICAL TOXICOLOGY. 
present. Fortunately, the detection of meconic acid does not in- 
clude similar difficulties, and, as its reactions are quite characteris- 
tic, its presence is held to be strong evidence of the existence of 
opium in an organic mixture. 
Stas's Process.—Minutely subdivide any solid matter; to 
this and the liquid portion of the vomit, etc. add about twice 
their weight of the strongest spirit of wine containing sufficient 
tartaric acid to fairly acidify the mixture. Digest the whole in 
a flask at a temperature of 150° or 160° F.; set aside to cool; 
filter. The solution, which will contain the whole of the alka- 
loid, should then be evaporated to dryness in vacuo, or at all 
events at a temperature not exceeding 100° F., lest volatile 
alkaloids should be dissipated. The residue is next exhausted 
with cold anhydrous alcohol, filtered, and the filtrate evapor- 
ated to dryness with the precautions already stated. The ex- 
tract is dissolved in a very small quantity of water, treated with 
excess of powdered bicarbonate of sodium or potassium, and 
well shaken with five or six times its volume of pure ether 
(with perhaps a little acetic ether). This ethereal liquid con- 
tains the alkaloid. Small portions should be evaporated in 
watch-glasses and tasted, or tested physically and chemically, 
according as the knowledge of collateral circumstances by the 
operator, or his experience or such reactions as are recorded on 
pp. 391—399, may suggest. 
If a volatile alkaloid (coniine, nicotine, hyoscyamine, lobe- 
line) is indicated, the ethereal solution, which may still contain 
animal matter, is removed, agitated with aqueous solution of 
potash, decanted, and shaken with pure diluted sulphuric acid. 
On standing, the aqueous portion, containing the alkaloid as 
acid sulphate, subsides; the upper ethereal portion containing 
the animal matter is rejected; the acid aqueous liquid is made 
alkaline with cairstic potash or soda ; ether added ; well shaken; 
the ethereal liquid decanted, evaporated to dryness in vacuo 
or at a low temperature, and (to get rid of all traces of ammo- 
nia) again moistened with ether and dried. The residue is now 
tested for the suspected alkaloid by taste, smell, and the appli- 
cation of appropriate reagents (pp. 391—399). 
If a non-volatile alkaloid (aconitine, atropine, brucine, col- 
chicine, emetine, physostigmine, solanine, veratrine, as well as 
morphine, codeine, and strychnine) is indicated, further puri- 
fication is effected by decanting ethereal liquid from the lower 
aqueous solution of bicarbonate of sodium, removing the ether 
by evaporation, digesting the residue in alcohol, filtering, evapor- 
Examination for other Poisonous Alkaloids. OTHER POISONOUS ALKALOIDS. 
501 
ating the alcohol, treating the residue with dilute sulphuric acid, 
setting aside for a few hours, filtering, concentrating, adding 
powdered carbonate of potassium, and finally anhydrous alcohol. 
The alcoholic liquid, on evaporation, yields the alkaloid in a fit 
state for testing in the manner already stated. 
Sonnenschein's Process.—Digest with diluted hydrochloric 
acid, evaporate to the consistence of syrup, dilute, set aside for 
some hours, filter. Add solution of phosphomolybdic acid so 
long as any precipitate falls or cloudiness occurs; collect the 
precipitate on a small filter ; wash it with water containing 
phosphomolybdic and nitric acid, and, while still moist, place it 
in a flask. Decompose this compound of phosphomolybdic acid 
and alkaloid by adding caustic baryta until the stirred mixture 
is distinctly alkaline. Distil off volatile alkaloids, condensing 
and collecting by help of a long tube so bent that the apparatus 
shall act as a retort, the end of the tube being attached to a 
bulb or series of bulbs containing dilute hydrochloric acid. 
The acid liquid evaporated gives a residue of hydrochlorates of 
alkaloids. The hitter will afford characteristic reactions with 
the tests for the suspected alkaloid, and, on being moistened 
with baryta-water and warmed, will afford fumes of volatile 
alkaloids whose odor is usually characteristic. The residue in 
the flask will contain non-volatile alkaloids. It is treated with 
carbonic acid gas to neutralize and precipitate the excess of 
baryta as insoluble carbonate of barium; the mixture is evap- 
orated to dryness over a water-bath, and the residue digested 
in alcohol. The alcoholic solution evaporated generally yields 
the alkaloids in a fit state for testing. 
Reagents for Alkaloids. 
Phosphomolybdic acid forms with ammonia, in acid solutions, a 
remarkably insoluble compound, and it comports itself in a similar 
manner with those compounds which are analogous to ammonia, the 
nitrogenized organic bases; consequently forming an excellent re- 
agent for their detection. It may be prepared in the following 
manner: Molybdate of ammonium is precipitated by phosphate 
of sodium ; the yellow precipitate, having been washed, is diffused 
through water, and heated with sufficient carbonate of sodium to 
dissolve it. The solution is then evaporated to dryness, and cal- 
cined to drive off the ammonia. In case any of the molybdic com- 
pound be reduced by this operation, the residue must be moistened 
with nitric acid and again calcined. The dry mass is then dissolved 
in cold water, the solution strongly acidulated with nitric acid, and 
water added until 10 parts of the solution contain 1 of the dry salt. 
The liquid, which is of a golden-yellow color, must be preserved from 
ammoniacal fumes. It precipitates all the alkaloids (with the excep- 502 
CH EM IC A Li TOXICOLOGY. 
tion of urea) when a mere trace only is present. The precipitates 
are yellow, generally flocculent, insoluble in water, alcohol, ether, 
and the dilute mineral acids, with the exception of phosphoric 
acid. Nitric, acetic, and oxalic acids, concentrated and boiling, 
dissolve them. These compounds are decomposed by the alkalies, 
certain metallic oxides, and the alkaline salts, which separate the 
alkaloid. To give an idea of the sensitiveness of this reagent, it 
may be stated that the 0.000071 gramme of strychnine gives an 
appreciable precipitate with one cubic centimetre of the solution 
of phosphomolybdic acid. 
Phosphoantimonic acid and phosphotungstic acid are also precip- 
itants of alkaloids. The chlorides of platinum, iridium, palladium, 
and gold are occasionally serviceable. Tannic acid and picric acid 
may too be used. 
Other special reagents for alkaloids are the “ Nessler test” (see 
Index), the double iodide of potassium and cadmium, and a solution 
of the double “ Iodide of Bismuth and Potassium.” The latter is 
made (by Thresh) on adding together 1 ounce of Liquor Bismuthi, 
B. P., 90 grains of iodide of potassium, and 90 grains of strong 
hydrochloric acid. This orange-colored solution gives a red precip- 
itate with dilute cold solutions containing alkaloids. 
Obscure Poisons.—Many substances, the active principles of which 
are at present beyond the reach of the chemical analyst, are poisons 
of a more or less active character. (See the Pharmaceutical Journal 
for Sept. 6, 1879, p. 195, and for Dec. 20, 1879, p. 481.) 
Ptomaines are poisonous alkaloids producible from the human 
body itself after death during the ordinary processes of decay. 
But they are distinguished, according to Bronardel and Boutmy, 
by a drop or two of a solution of their sulphate converting a drop 
of solution of ferrocyanide of potassium into ferrideyanide, the mix- 
ture then giving a dark-blue precipitate with a ferric salt. Unfor- 
tunately, some other substances possess this converting power. 
ANTIDOTES. 
Vide “Antidote” in the Index. 
878. In examining food and similar matter for poison, why must 
not the ordinary tests for the poison be at once applied? 
879. What preliminary operations should be performed on a vomit 
in a case of suspected poisoning ? 
880. How would you proceed in searching for corrosive sublimate 
in wine? 
881. By what series of operations would you satisfy yourself 
of the presence or absence of arsenic in the contents of a 
stomach ? 
QUESTIONS AND EXERCISES. MORBID URINE AND CALCULI. 
503 
882. Describe the treatment to which decoction of coffee should be 
subjected in testing it for tartar-emetic. 
883. State the method by which the occurrence of lead in water 
is demonstrated. 
884. Give a process for the detection of copper in jam. 
885. How would you detect zinc in a vomit? 
886. How may the presence of a poisonous quantity of sulphuric 
acid in gin be proved ? 
887. In examining ale for free nitric acid what reactions would be 
selected ? 
888. Show how you would conclude that a dangerous quantity 
of hydrochloric acid had been added to cider. 
889. Describe the manipulations necessary in testing for hydro- 
cyanic acid in the contents of a stomach, 
890. By what method is oxalic acid discovered in infusion of 
coffee ? 
891. IIow is the phosphorus detected in organic mixtures? 
892. Give the process by which strychnine is isolated from par- 
tially digested food. 
893. Mention the experiments by which the presence of laudanum 
in porter is demonstrated. 
894. Name the appropriate antidotes in cases of poisoning by— 
o, alkaloids; b, antimonials; c, arsenic ; d, barium salts; e, copper 
compounds ; J\ hydrochloric acid ; g, hydrocyanic acid ; h, prepara- 
tions of lead ; i, corrosive sublimate ; j, nitric acid ; k, oxalic acid ; 
l, salts of silver ; m, oil of vitriol; n, tin liquors ; o, zinc solutions ; 
p, carbolic acid. 
EXAMINATION OF MORBID URINE AND 
CALCULI. 
The various products of the natural and continuous decay of 
animal tissue and the refuse matter of food are eliminated from the 
system chiefly as faeces, urine, and expired air. Air exhaled from 
the lungs carries off from the blood much carbon (about 8 ounces in 
twenty-four hours) in the form of carbonic acid gas and some aque- 
ous vapor—the latter, together with a small amount of oily matter, 
also escaping by the skin. Directing the breath to a cold surface 
renders moisture evident, and breathing through a tube into lime- 
water demonstrates the presence of a considerable quantity of car- 
bonic acid gas. The faeces consist mainly of the insoluble debris of 
the system, the soluble matters and water forming the urine. These 
excretions vary considerably according to the food and general 
habits of the individual and external temperature. But in disease 
the variations become excessive; their detection by the medical 
practitioner, or by the pharmacist for the medical practitioner, is 
therefore a matter of importance. 
A complete analysis of faeces, urine, or expired air cannot be per- 
formed in the present state of our knowledge. Nor can even a par- 
tial analysis of faeces or air be made with sufficient ease and rapid- 504 
MORBID URINE. 
ity to be practically available in medical diagnosis. But with regard 
to urine, certain abnormal substances and abnormal quantities of 
normal constituents may be chemically detected in the course of a 
few minutes by any one having already some knowledge of chem- 
ical manipulation. 
Healthy human urine contains, in 1000 parts, 957 of water, 14 of 
urea, 1 of uric acid, 15 of other organic matter, and 13 of inorganic 
salts. The amount passed in twenty-four hours varies from two to 
three pints in an adult, and its specific gravity, if healthy, will 
range from 1.015 to 1.025. The acidity of urine Thudichum consid- 
ers to be due to cryptophanic acid, H2C5H7N05. 
Examination of Morbid Urine for Albumen, Sugar, 
Bile, and Excess of Urea; and Urinary Sediment 
for Urates (or Lithates), Phosphates, Oxalate of 
Calcium, and Uric Acid. 
Albumen.—To detect albumen, acidulate a portion of the 
clear urine in a test-tube with a few drops of acid (to keep 
phosphates in solution—nitric is best, acetic not so good), and 
boil; flocks or coagula will separate if albumen be present. 
This experiment should first be made on normal urine contain- 
ing a drop or two of solution of white of egg. The coagulum is 
white if it is only albumen, greenish if bile-pigment be present, 
and brownish-red if the urine contain blood. The influence of 
acids and alkalies on the precipitation of albumen is noticed on 
page 456. 
The occurrence of albumen in the urine may be temporary and 
of but little importance, or it may indicate the existence of a serious 
affection known as Bright's disease. 
Sugar.—To a portion of the clear urine in a test-tube add 
five or ten drops of solution of sulphate of copper; pour in 
solution of potash or soda until the precipitate first formed is 
redissolved; slowly heat the solution to near the boiling-point; 
a yellow, yellowish-red, or red precipitate (cuprous oxide) is 
formed if sugar be present. 
This experiment should first be made on urine containing a drop 
or two of solution of grape-sugar (page 411). The hydrate of cop- 
per precipitated by the alkali is insoluble in excess of pure potash 
or soda, but readily dissolves if organic matter, especially sugar, be 
present. The copper salt may not contain iron. 
Other tests may be applied if necessary (vide pages 411 et seq.) 
A minute amount of sugar is said to occur in normal urine, and a 
distinct trace is occasionally present. In larger quantities (often 5 
per cent.) it is a characteristic constituent of the urine of diabetic 
patients, greatly increasing the specific gravity of the excretion. 
Small hydrometers (termed urinometers) are commonly employed 
for quickly and readily ascertaining the specific gravity of urine; BILE, UREA, ETC. 
505 
they range from 1.000 to 1.050, the interval of 1.015 to 1.025 being 
marked as “ II. S.” or healthy state. ( Vide “ Specific Gravity ” and 
“Hydrometers” in Index.) 
Bile.—This is best detected by the general test (Pettenkofer’s, 
or, still better, Quinlan’s) described on page 464. Or a little of the 
urine may be placed on a white plate, and strong nitric acid dropped 
on it; a peculiar play of colors—green, yellow, violet, etc.—occurs 
if (the coloring-matter of) bile be present (Gmelin). A somewhat 
similar iridescence is produced in the presence of the indigo-forming 
matter occasionally found in urine. 
Excess of Urea.—About one-third of the solid matter in the 
urine is urea. Its proportion varies considerably, but 1? per 
cent, may be regarded as an average amount. Concentrate 
urine slightly by evaporation in a small dish, pour the liquid 
into the test-tube, set the tube aside till cold, or cool it by 
letting cold water run over the outside; add an equal bulk of' 
strong nitric acid and again set aside; scaly crystals of nitrate 
of urea are deposited more or less quickly. 
With regard to the amount of urea in urine it is impossible to 
sharply define excess or deficiency. If nitric acid gives crystals 
without concentration, excess is certainly present. A rough esti- 
mate may be formed by mixing a few drops of the urine and acid 
on a piece of glass and setting aside; the time which elapses before 
crystals form is an indication of the quantity in the specimen. The 
time will vary according to the temperature and state of moisture 
of the atmosphere, but with care some useful comparative results 
may in this way be obtained. 
For methods of estimating the amount of urea in urine, and for 
drawings of the necessary apparatus, vide Journal of the Chemical 
Society, 1874, p. 749; and 1877, i. pp. 534 and 538; also Chemical 
News, Jan. 22, 1875. 
Tests.—Urea in solution in water may be detected by the above 
reaction with nitric acid and by the readiness with which it yields 
ammonia on being boiled with alkalies. In putrid urine its conver- 
sion into an ammoniacal salt has already been effected by ammo- 
niaeal fermentation. 
CH4N20 + 2TI,0 = (NH4)2CO,. 
Urea. Water. Carbonate of ammonium. 
This transformation of the urea into carbonate of ammonium is 
due to the action of a special ferment belonging to the genus 
Torulacei, formed of chaplets of globules similar in form to, but 
much smaller than, those of beer-yeast. It occurs as a white 
deposit in the urine. If some of this deposit be added to a sac- 
charine solution containing urea, it rapidly multiplies, carbonate 
of ammonium being formed. 
Formula of Urea.—The empirical formula of urea is CII4N20. 
(CO)" | 
Its rational formula may be thus written :— II2 > N2; that is, 
Haj 506 
MORBID URINE. 
it may be regarded as one of the organic bases already referred to, 
a primary diamine, in which the bivalent radical CO occupies the 
place of II2. The other atoms of hydrogen may be displaced by 
various radicals, and many compound ureas thus be obtained. 
Artificial Urea.—Urea may be prepared artificially by Williams's 
modification of Wohlers method. Cyanide of potassium of the best 
commercial quality (containing about 90 per cent, of real cyanide) 
is fused at a very low red heat in a shallow iron vessel; red lead is 
added in small quantities at a time, the temperature being kept down 
by constant stirring. When the red lead ceases to cause further 
action, the mixture (cyanate of potassium and lead) is allowed to 
cool, the product finely powdered, exhausted with cold water, nitrate 
of barium added till no more precipitate (carbonate of barium) falls, 
the mixture filtered, and the filtrate treated with nitrate of lead so 
long as cyanate of lead is thrown down. The latter is thoroughly 
washed, and dried at a low temperatnre. Equivalent quantities of 
cyanate of lead and sulphate of ammonium, digested in a small 
quantity of water at a gentle heat and filtered, yield a solution from 
which urea crystallizes on cooling. 
Another Process.—Basaroff has found that urea is produced when 
ordinary carbonate of ammonium is heated in hermetically sealed 
tubes to about 275° F. for a few hours. The same chemist had pre- 
viously obtained urea by similarly heating pure carbonate of ammo- 
nium, so that the source of the urea in the former case is probably 
the carbamate of ammonium believed to occur in the carbonate (see 
p. 91). 
NII4NII2C02 — II20 = CH4N20. 
Notes.—Urinary deposits are seldom of a complex character; the 
action of heat and acetic and hydrochloric acids generally at once 
indicates the character of the deposit, rendering filtration and pre- 
cipitation unnecessary. 
The urates are often of a pink or red color, owing to the presence 
of a pigment termed purpurine; hence the common name of red 
gravel for such deposits. Purpurine is soluble in alchol, and may 
be removed by digesting a red deposit in that solvent. It is seldom 
necessary to determine whether the urate be that of ammonium, cal- 
cium, or sodium (see also Uric Acid, p. 357). 
The phosphate of calcium and the ammonio-magnesium phosphate 
are usually both present in a phosphatic deposit, the magnesium 
salt forming the larger proportion. They may, if necessary and if 
sufficient in quantity, be separated by collecting on a filter, washing, 
and boiling with solution of carbonate of sodium. The carbonates 
of calcium and magnesium thus formed are collected on a filter, 
washed, and dissolved in a drop or two of hydrochloric acid ; chlo- 
ride of ammonium, ammonia, and carbonate of ammonium are 
added, and the mixture boiled and filtered; any calcium originally 
present will then remain insoluble as carbonate of calcium, while 
any magnesium will be precipitated from the filtrate as ammonio- 
magnesium phosphate on the addition of phosphate of sodium, the 
mixture being also well stirred. The chief portion of excreted URINARY SEDIMENTS. 
507 
phosphates is carried off by the faeces, that remaining in the urine 
being kept in solution by the influence of acid phosphate of sodium, 
and frequently lactic acid. Occasionally, an hour or two after a 
hearty meal, the urine becomes sufficiently alkaline for the phos- 
phates to be deposited, and the urine when passed is turbid from 
their presence. The ammoniacal constituent of the magnesium 
salt does not occur normally, but is produced from urea as soon as 
urine becomes alkaline. 
Warm the sediment with the supernatant urine and filter. 
Urinary Sediments. 
Insoluble. 
Phosphates, oxalate of calcium, and uric 
acid. 
Warm with acetic acid, and filter. 
Soluble. 
Urates—of ammonium, 
calcium, or sodium, 
chiefly the latter. 
They are redeposited 
as the liquid cools, and 
if sufficient in quantity 
may be further exam- 
ined for ammonium, 
calcium, sodium, and 
the uric radical by the 
appropriate tests. 
Insoluble. 
Oxalate of calcium ana uric 
acid. 
Warm with hydrochloric 
acid, filter. 
Soluble. 
Phosphates. 
Add ammo- 
nia, white ppt. 
= phosphate 
of calcium, or 
ammonio-mag- 
nesium phos- 
phate, or both. 
Insoluble. 
Uric acid. 
Apply mu- 
rexid test (p. 
358). 
Soluble. 
Oxalate of 
calcium. 
May be pre- 
cipitated by 
ammonia. 
Oxalate of calcium is seldom met with in excessive amounts, but 
very often in small quantities mixed with phosphates. 
In one case of oxaluria the whole urine excreted by a patient in 
twenty-four hours furnished to the author only two-thirds of a grain 
of oxalate of calcium. 
Free uric acid is in most cases distinctly crystalline, and nearly 
always of a yellow, red, or brown color. 
Artificial Sediments.—For educational practice artificial deposits 
may be obtained as follows :—1. Rub up in a mortar a few grains of 
serpent’s excrement (chiefly urate of ammonium) with an ounce or 
two of urine; this represents a sediment of urates. 2. Add a few 
drops of solution of chloride of calcium and of phosphate of sodium 
to urine; the deposit may be regarded as one of phosphates. 3. To 
an ounce or two of urine add very small quantities of chloride of 508 
MORBID URINE. 
calcium and oxalate of ammonium ; the precipitate is oxalate of cal- 
cium. 4. To urine acidulated by hydrochloric acid add a little ser- 
pent’s excrement; the sediment is uric acid. 
Other deposits than the foregoing are occasionally observed. Thus 
hippuric acid (IIC9II8N03), a normal constituent of human urine, 
and largely contained in the urine of herbivorous animals, is some- 
times found associated with uric acid in urinary sediment, especially 
in that of patients whose medicine contains benzoic acid (p. 333). 
Its appearance, as observed by the aid of the microscope, is charac- 
teristic—namely, slender, four-sided prisms, having pointed ends. 
Cystin (0311,11 SO.,) (from kvotiq, kustis, a bladder, in allusion to its 
origin) rarely occurs as a deposit in urine. It is not soluble in 
warm urine or dilute acetic acid, and scarcely in dilute hydrochloric 
acid, hence would be met with in testing for free uric acid. It is 
very soluble in ammonia, recrystallizing from a drop of the solu- 
tion placed on a piece of glass in characteristic microscopic six- 
sided plates. Organized sediments may be due to the corpuscles 
of pus, mucus, or blood, fat-globules, spermatozoa, cylindrical casts 
of the tubes of the kidneys, epithelial cells from the walls of the 
bladder, or foreign matters, such as fibres of wood, cotton, small 
feathers, dust, starch; these are best recognized by the microscope, 
as will be seen by the following paragraphs and figures on the 
microscopic appearances of both crystalline and organized urinary 
sediments. 
Microscopic Examination op Urinary Sediments. 
Urine containing insoluble matter is usually more or less opaque. 
For a microscopical examination a few ounces should be set aside in 
a conical test-glass for an hour or two, the clear supernatant urine 
poured off from the sediment as far as possible, a small drop of the 
residue placed on a slip of glass and covered with a piece of thin 
glass, and examined under the microscope with different magnifying 
powers. 
[The respective appearances of the various crystalline and or- 
ganized matters are given in the following figures, which were 
kindly drawn by II. B. Brady, F. R. S., from natural specimens (as 
seen with a two-third inch objective and No. 1 eye-piece—i. e., mag- 
nified 60 diameters) in the collections of St. Bartholomew’s Hos- 
pital, Dr. Sedgwick, \V. W. Stoddart, F. C. S., Mr. Waddington, and 
the author.] 
Uric Acid occurs in many forms, most of which are given in the 
first two figures. Flat, more or less oval crystals, sometimes at- 
tached to each other, their outline then resembling an 8, a cross, or 
a star, are common. Single and grouped quadratic prisms, aigrettes, 
spicula, and crystals recalling dumb-bells are met with. From urine 
acidulated by hydrochloric acid square crystals, two opposite sides 
smooth and two jagged, are generally deposited; acidulated by 
acetic acid, more typical forms are obtained. A drop of solution 
of potash or soda placed on a glass slip will dissolve a deposit of 
uric acid, a drop of any acid reprecipitating it in minute but charac- 
teristic crystals. URINARY SEDIMENTS. 
509 
Cystin is very rarely met with as a urinary deposit; that from 
which the figure was taken was found in the urine of a patient in 
St. Bartholomew’s Hospital. Lamellae of cystin always assume an 
hexagonal character, but the angles are sometimes ill defined and 
the plates superposed : in the latter case, a drop of solution of am- 
monia placed on the glass at once dissolves the deposit, well-marked 
six-sided crystals appearing as the drop dries up. 
Fig. 50. 
Fig. 51. 
Uric Acid. 
Uric Acid. 
Triple Phosphate (phosphate of magnesium and ammonium) is 
deposited as soon as urine becomes alkaline, the ammoniacal con- 
stituent being furnished by the decomposition of urea. It occurs 
Fig. 52. 
Fig. 53. 
Cystin. 
Triple Phosphate. 
in large prismatic crystals, forming a beautiful object when viewed 
by polarized light; sometimes also in ragged stellate or arborescent 
crystals resembling those of snow. Both forms may be artificially 510 
MORBID URINE. 
prepared by adding a small lump of carbonate of ammonium to a 
few ounces of urine and setting aside in a test-glass. 
Amorphous deposits are either earthy phosphates (a mixture of 
phosphates of magnesium and calcium) or urates (of calcium, mag- 
nesium, ammonium, potassium, or sodium—chiefly the latter). They 
may be distinguished by the action of a drop of acetic acid placed 
near the sediment on the glass slip, the effect being watched under 
the microscope; phosphates dissolve, while urates gradually assume 
characteristic forms of uric acid. Urates redissolve when warmed 
with the supernatant urine. 
Urates of Sodium and Magnesium, though generally amorphous, 
occasionally take a crystalline form—bundles or tufts of small 
needles—as shown in the cut. 
Oxalate of Calcium commonly occurs in octahedra requiring high 
magnifying-power for their detection. The crystals are easily over- 
looked if other matters are present, but are more distinctly seen after 
phosphates have been removed by acetic acid. In certain aspects the 
smaller crystals look like square plates traversed by a cross. A 
dumb-bell form of this deposit is also sometimes seen, resembling 
certain forms of uric acid and the coalescing spherules of a much 
rarer sediment, carbonate of calcium. Oxalate of calcium is insol- 
uble in acetic, but soluble in hydrochloric, acid. The octahedra are 
frequently met with in the urine of persons who have partaken of 
garden rhubarb; the crystals may often be deposited artificially (ac- 
cording to Waddington) by dropping a fragment of oxalic acid into 
several ounces of urine and setting aside for several hours. 
Fig. 54. 
Fig. 55. 
Urates. 
a, of Sodium: 
b, of Magnesium. J 
Oxalate of Calcium. 
Carbonate of Calcium. 
Hippuric Acid. 
Carbonate of Calcium is rarely found in the urine of tnan, but 
frequently in that of the horse and other herbivorous animals. Hu- 
man urine containing carbonate of calcium often reddens litmus- 
paper ; and it is only after the removal, on standing, of the excess of 
carbonic acid that the salt is deposited. It consists of minute spher- 
ules, varying in size, the smaller ones often in process of coalescence. URINARY SEDIMENTS. 
511 
The dumb-bell form thus produced is easily distinguished from simi- 
lar groups of uric acid or oxalate of calcium by showing a black 
cross in each spherule when viewed by polarized light. Acetic acid 
dissolves carbonate of calcium, liberating carbonic acid gas, with 
visible effervescence (under the microscope) if the slide has been pre- 
viously warmed and a group of crystals be attacked. 
Hippuric Acid.—The pointed rhombic prisms and acicular crys- 
tals are characteristic and easily recognized. The broader crystals 
may possibly be mistaken for triple phosphate, and the narrower for 
certain forms of uric acid; but insolubility in acetic acid distin- 
guishes them from the former, and solubility in alcohol from the 
latter. These tests may be applied while the deposit is under 
microscopic observation. An alcoholic solution of hippuric acid 
evaporated to dryness, and the residue treated with water, gives a 
solution from which characteristic crystalline forms of hippuric acid 
may be obtained on allowing a drop to dry upon a slip of glass. 
The organized deposits in urine entail greater care in their deter- 
mination, and usually require a higher magnifying-power for their 
proper examination, than those of crystalline form. The figures are 
drawn to 230diameters. The following notes will assist the observer:— 
Casts of uriniferous tubuli are fibrinous masses of various forms, 
and often of considerable length—sometimes delicate and trans- 
parent, occasionally granular, and often beset with fat-globules. 
Epithelial debris are frequently present in urine in the form of 
nucleated cells, regular and oval when full, but angular and un- 
symmetrical ivhen partially emptied of their contents—sometimes 
perfect, but more frequently a good deal broken up. 
Fig. 56. 
Fig. 57. 
Blood is easily recognized. Urine containing it is high-colored, 
and the corpuscles appear under the microscope as reddish circular 
disks, either single or laid together in strings resembling piles of 
coin. Their color and sometimes smaller size serve to distinguish 
them from pus-corpuscles. In doubtful cases a minute drop of 
blood taken from a finger by help of a needle should be diluted 
Epithelial Cells and Tubuli. 
Blood-Corpuscles. 512 
MORBID URINE. 
with water and used for comparison. After urine containing blood 
has stood for some time the corpuscles lose their regular outline and 
become angular. (See a in the figure.) Day, of Geelong, tests for 
blood in urine or in stains on clothing by adding a few drops of a 
recently-prepared alcoholic solution of the inner unoxidized portions 
of guaiacum rosin, and then a small quantity of Robbins's aqueous or 
ethereal solution of peroxide of hydiogen, when a blue color results. 
“If the stain is on a dark-colored fabric, the moistened parts may be 
pressed with white blotting-paper, when blue impressions will be ob- 
tained. Contact with many substances causes the blue reaction or 
oxidation of guaiacum ; the peculiarity of blood is that it does not 
produce this effect unless peroxide of hydrogen or a similar ‘ anto- 
zonic ’ liquid is present. Bodies such as permanganate of potassium, 
whose oxygen is, apparently, in the form of ozone, also give rise to 
a blue color with guaiacum ; peroxide of hydrogen and other com- 
pounds whose oxygen is in the opposite, positive, or, according to 
Schijnbein, antagonistic condition, produce no such effect. It would 
seem as if blood or some other constituent of blood has the power 
of converting positive into negative oxygen, and thus bring about 
an effect which negative oxygen alone is able to produce; for of all 
substances which, like blood, do not alone cause guaiacum to become 
blue, blood is the only one that so affects ‘ antozonides ’ (themselves 
inactive) as to enable them to act as ozonides—that is, to oxidize the 
guaiacum. Both the venous and arterial fluid from any red-blooded 
animal will produce this blue reaction. Fruit-stains are darkened 
by ammonia, which does not alter the color of blood. Iron-stains 
or iron-mould yields no color to water, whereas the red coloring-mat- 
ter of blood is soluble in water. The peroxide of hydrogen should 
be free from more than a trace of acid.” 
The blood-corpuscles of ordinary animals are much smaller than 
those of man, but a or -fa of 
an inch lens is necessary for 
proper differentiation (-J. G. 
Richardson). 
Pus and Mucus. — Purulent 
urine deposits, on standing, a 
light-colored layer, easily dif- 
fused thi’ough the liquid by 
shaking. Acetic acid does not 
dissolve the sediment, and so- 
lution of potash, of official 
strength, converts it into a 
gelatinous mass. Under the 
microscope, pus-corpuscles ap- 
pear rounded and colorless, 
rather larger than blood-disks, 
and somewhat granular on the 
surface. They generally show 
minute nuclei, which are more 
distinctly seen after treatment with acetic acid. (See the portion of 
the figure marked a.) Mucus possesses no definite microscopic eha- 
Fig. 58. 
Pus-Corpuscles. URINARY SEDIMENTS. 
513 
racters, but commonly has imbedded in it pus, epithelium, and air- 
bubbles. Mucus is coagulated in a peculiar and characteristic manner 
by acetic acid; and this reaction, together with the ropy appear- 
ance it imparts to urine, prevents its being confounded with pus. 
Day’s test for pus consists in adding a drop or two of oxidized 
tincture of guaiacum to the urine or other liquid, when a clear blue 
color is produced. It is necessary to moisten dry pus with water 
before applying the test. The 
test-liquid is made by exposing 
a saturated alcoholic solution of 
guaiacum to the air until it has 
absorbed a sufficient quantity of 
oxygen to give it the property 
of turning green when placed 
in contact with iodide of potas- 
sium. Day’s test for mucus 
consists in the application, first, 
of oxidized tincture of guaiac- 
um, which by itself undergoes 
no change in the presence of 
mucus, and then in the addition 
of carbolic acid or creasote, 
which quickly changes the color 
of the guaiacum to a bright 
blue. Neither carbolic acid 
nor creasote alone will render 
guaiacum blue. In testing for mucus on cloths or when it is mixed 
with blood, it is necessary to use the carbolic acid pure, but when 
the mucus is in a liquid state it is better to use carbolic acid diluted 
with alcohol. 
Saliva.—Saliva is an aqueous fluid containing less than 1 per 
Fig. 59. 
Fat-Globules. 
Fig. 60. 
Fig. 61. 
cent, of solid matter, of which one-third is an albumenoid substance 
termed ptyalin (from tttveXov, spittle), a body that has power of con- 
Spermatozoa. 
Sarcina ventriculi. 514 
MORBID URINE. 
verting starch into dextrin and grape-sugar. Alkaline salts, includ- 
ing a trace of sulphocyanate of potassium, and calcareous compounds 
are also present. 
Day’s test for saliva in urine, etc. is similar to that for mucus, 
with the exception that the blue reaction produced by the oxidized 
tincture of guaiacum and alcoholic solution of carbolic acid is highly 
intensified by the addition of Robbins’s aqueous or ethereal solution 
of peroxide of hydrogen. 
Fatty matter occurs either as minute globules partially diffused 
through the urine (as shown at a, Fig. 59) or in more intimate emul- 
sion (as at b). When present in larger quantity it collects as a sort 
of scum on the surface after standing. 
Spermatozoa are liable to escape notice on account of their small 
size and extreme transparency. Suspected urine should be allowed 
to settle some hours in a conical test-glass, and the drop at the bot- 
tom examined under a high power. The drawing (Fig. 60) shows 
their tadpole-like appearance. 
Sarcina ventriculi is an alga of a very rare occurrence in urine, 
though not unfrequent in the matters vomited during certain dis- 
eases of the stomach. The upper figures (a, Fig. 61) are copied 
from Dr. Thudichum’s drawing (from urine) ; the larger fronds (5) 
are from vomited matter. 
Extraneous bodies, such as hair, wool, or fragments of feathers, 
are often found in urinary deposits, and ludicrous mistakes have 
been made by observers not on their guard in respect to such casual 
admixtures. 
The term calculus is the diminutive of calx, a lime- or chalk- 
stone. 
Knowledge of the composition of a calculus or urinary deposit 
affords valuable diagnostic aid to the physician ; hence the import- 
ance of a correct analysis of these substances. 
Nature of Calculi.—Urinary calculi have the same composition 
as unorganized urinary sediments. They consist, in short, of sedi- 
ments that have been deposited slowly within the bladder, particle 
on particle, layer on layer, the several substances becoming so com- 
pact as to be less easily acted on by reagents than when deposited 
after the urine has been passed—the urates less readily soluble in 
warm water, the calcic phosphate insoluble in acetic acid until it 
has been dissolved in hydrochloric acid and reprecipitated by an 
alkali. 
Preliminary Treatment.—If the calculus is whole, saw it in two 
through the centre, and notice whether it is built up of distinct 
layers or apparently consists of one substance. If the latter, use 
about a grain of the sawdust for the analysis; if the former, care- 
fu.ly scrape off portions of each layer and examine them separately. 
If the calculus is in fragments, select fair specimens of about half 
a grain or a grain each, and reduce to a fine powder by placing on 
a hard surface and crushing under the blade of a knife. 
Examination of Urinary Calculi. URINARY CALCULI. 
515 
Analysis.—Commence the analysis by heating a portion, 
about the size of a pin’s head, on platinum foil, in order to 
ascertain whether organic matter, inorganic matter, or both are 
present. If both, the ash is examined for inorganic substances, 
and a fresh portion of the calculus for uric acid by the murexid 
test. (In the absence of uric acid any slight charring may be 
considered to he due to indefinite animal matter.) If composed 
of organic matter only, the calculus will in nearly all cases be 
uric acid, the indications being confirmed by applying the mu- 
rexid test, in a watch-glass, to another fragment half the size 
of a small pin’s head. If inorganic only, the ash on the plati- 
num foil may be examined for phosphates, and a separate por- 
tion of the calculus for oxalates. Even a single drop of liquid 
obtained in any of these experiments may be filtered by placing 
it on a filter not larger than a sixpence and previously moist- 
ened with water, and adding three or four drops of water one 
after the other as each passes through the paper. If the cal- 
culus is suspected to contain more than one substance, boil 
about half a grain of the powder in half a test-tubeful of dis- 
tilled water for a few minutes, and pour it on a small filter; 
then proceed according to the following Table :— 
Insoluble. 
Soluble. 
Phosphates, oxalate of calcium, and free 
uric acid. 
Boil with two or three drops of hydrochloric 
acid, and filter. 
Urates. 
These will prob- 
ably be redepos- 
ited as the solution 
cools. Small quan- 
tities may be de- 
tected by evaporat- 
ing the solution to 
dryness. They are 
tested for ammo- 
nium, sodium, cal- 
cium, and the uric 
radical by the ap- 
propriate reagents. 
Insoluble. 
Uric acid. 
Apply the 
murexid 
test 
(p. 358). 
Soluble. 
Phosphates and oxalate of 
calcium. 
Add excess of ammonia, and then 
excess of acetic acid ; filter. 
Insoluble. 
Soluble. 
Oxalate of 
calcium. 
Phosphates. 
They may be repre- 
cipitated by ammonia. 
Varieties of Calculi.—Calculi composed entirely of uric acid are 
common ; a minute portion heated on platinum foil chars, burns, 516 
MORBID URINE. 
and leaves scarcely a trace of ash. The phosphates frequently 
occur together, forming what is known as the fusible calculus from 
the readiness with which a fragment aggregates, and even fuses to 
a bead, when heated on a loop of platinum wire in the blow pipe- 
flame. The phosphates may, if necessary, be further examined by 
the method described in connection with urinary deposits. Oxalate 
of calcium often occurs alone, forming a dark-colored calculus hav- 
ing a very rough surface, bence termed the mulberry calculus. 
Smaller calculi of the same substance are called, from their appear- 
ance, hempseed calculi. Calculi of cystin are rarely met with. 
Xanthin (from ijavdoc, xanthos, yellow', in allusion to the color it 
yields with nitric acid) less often occurs as a calculus. The earthy 
concretions, or chalk-stones, which frequently form in the joints of 
gouty persons are composed chiefly of urates, the sodium salt being 
that most commonly met writh. Gall-stones, or biliary calculi, occa- 
sionally form in the gall-bladder; they contain cholesterin (from 
Xo1.ii, chole, bile, and art:pew;, stereos, solid), a fatty substance of 
alcoboloid constitution, soluble in rectified spirit or ether, and crys- 
tallizing from such solutions in well-defined, square, scaly crystals. 
Phosphatic and other calculi of many pounds weight are occasion- 
ally found in the stomach and larger intestines of animals. 
QUESTIONS AND EXERCISES. 
895. In breathing, how much carbon (in the form of carbonic acid 
gas) is exhaled from the lungs every 24 hours? 
896. How may the presence of carbonic acid gas in expired air be 
demonstrated? 
897. Mention an experiment showing the escape of moisture from 
the lungs during breathing. 
898. State the method of testing for albumen in urine. 
899. Give the tests for sugar in urine. 
900. What is the average composition of healthy urine? 
901. Give the tests for urea. 
902. Write the rational formulae of some compound ureas in 
which methyl or ethyl displaces hydrogen. 
903. Describe an artificial process for the production of urea, 
giving equations. 
904. Sketch out a plan for the chemical examination of urinary 
sediments. 
905. A deposit is insoluble in the supernatant urine or in acetic 
acid ; of what substance may it consist? 
906. Which compounds are indicated when a deposit redissolves 
on warming it with the supernatant urine? 
907. Name the salts insoluble in warmed urine, but dissolved on 
the addition of acetic acid. 
908. Mention the chemical characters of cystin. At what stage 
of analysis would it be recognized? OFFICIAL GALENICAL PREPARATIONS. 
517 
909. Describe the microscopical appearance of the following 
urinary deposits:— 
Uric acid. Tube-casts. 
Cystin. Epithelial debris. 
Triple phosphate. Blood. 
Earthy phosphates. Pus. 
Urates. Mucus. 
Oxalate of Calcium. Fat. 
Carbonate of Calcium. Spermatozoa. 
Ilippuric Acid. Sarcina. 
Extraneous Bodies. 
910 How are Day’s tests for blood, pus, and saliva applied? 
911. What is the general, physical, and chemical nature of urinary 
calculi ? 
912. How are urinary calculi prepared for chemical examination? 
913. Draw out a chart for the chemical examination of urinary 
calculi. 
914. Why is the “ fusible calculus” so called? and what is its 
composition ? 
915. State the characters of “mulberry” and “hempseed” 
calculi. 
916. What are the “ chalk-stones ” of gout, and “ gall-stones ” 
or “biliary calculi”? 
TIIE GALENICAL PREPARATIONS OF THE 
PHARMACOPOEIAS. 
The preparation of Abstracts, Cerates, Confections, Decoc- 
tions, Elixirs, Enemas, Extracts, Glycerins, Infusions, Inhala- 
tions, Juices, Liniments, Lozenges or Troches, Mixtures, Oint- 
ments, Pills, Plasters, Poultices, Powders, Spirits, Suppositories, 
Syrups, Tinctures, Triturations, and Wines includes a number 
of mechanical rather than chemical operations, and belongs to 
the domain of pure Pharmacy. The medical or pharmaceutical 
pupil will have had ample opportunity of practically studying 
those compounds before working at experimental chemistry, and 
will probably have prepared many of them according to the 
directions of the Pharmacopoeias; if not, he is referred to the 
pages of the last edition of those works for details. 
Among the extracts of the British Pharmacopoeia, however, 
there are five (namely, those of Aconite, Belladonna, Hemlock, 
Henbane, and Lettuce) which are not simply evaporated infu- OFFICIAL GALENICAL PREPARATIONS. 
sions, decoctions, or tinctures, like most others, but are evapor- 
ated juices from which vegetable albumen, the supposed source 
of fermentation and decay, has been removed, and chlorophyll 
(the green coloring-mater of plant-juice) retained, practically 
unimpaired in tint. For educational practice either of the 
above-named five raw materials may be employed ; but in order 
that attention may be concentrated on the process by which 
the extracts are prepared, rather than />n any one of the ex- 
tracts themselves, it suffices to make an extract of some ordi- 
nary green vegetable, such as cabbage or turnip-tops. Bruise 
the green leaves of a good-sized cabbage in a mortar, and press 
out the juice: heat it gradually to 130° F., and remove the 
green flocks of chlorophyll which separate, by filtration through 
calico. When the liquor has all passed through the filter, set 
the chlorophyll aside for a time, heat the strained liquor to 
200° F. to coagulate albumen; remove the latter by filtration 
and throw it away; evaporate the filtrate by a water-bath to 
the consistence of thin syrup; then add to it the chlorophyll, 
and, stirring the whole together assiduously, continue the 
evaporation at a temperature not exceeding 140° F. until the 
extract is of a suitable consistence for forming pills. A higher 
temperature than that indicated would cause the alteration of 
the chlorophyll to a dark-brown substance, any such extract 
used in pharmacy no longer having the green tint which cus- 
tom and the British Pharmacopoeia demand. 
QUESTIONS AND EXERCISES. 
917. Enumerate the different classes into which official galenical 
preparations may be divided. 
918. Describe the general process for the preparation of green 
extracts:— 
Aconite. Hemlock. 
Belladonna. Henbane. 
Lettuce. 
919. Why is vegetable albumen excluded in the preparation of 
green extracts? 
920. How may chlorophyll be removed from vegetable juices, and 
again be introduced into their evaporated residues, without destroy- 
ing its color ? 
921. For what reason is exposure of chlorophyll to a boiling tem- 
perature avoided in the manufacture of green extracts? QUANTITATIVE ANALYSIS. 
519 
THE CHEMICAL PREPARATIONS OF THE 
PHARMACOPOEIAS. 
The process by which every official chemical substance is 
prepared has already been described, and the strict chemical 
character of the processes illustrated by experiments and ex- 
plained by aid of equations. Should the reader, in addition, 
desire an intimate acquaintance with those details of manipu- 
lation on which the successful and economic manufacture of 
chemical substances depends, he is advised to prepare, if he 
has not done so already, a few ounces of each of the salts men- 
tioned in the Pharmacopoeias or commonly used in Pharmacy. 
An additional guide in these operations will be the Pharmaco- 
poeia itself. 
The production of many chemical and galenical substances 
on a commercial scale can only be successfully carried on in 
manufacturing laboratories and with some knowledge of the 
circumstances of supply and demand, value of raw material and 
of by-products, etc.; for the technical preparation of such sub- 
stances requires much knowledge beyond even a thorough 
acquaintance with Chemistry. Still, in the present day, com- 
mercial Chemistry and Pharmacy can best hope for success 
when founded on the working out of abstract scientific princi- 
ples. The problem of manufacturing success is now only solved 
with certainty by sound and wisely-applied science. 
Memorandum.—The next subject of experimental study will 
be determined by the nature of the student’s future pursuits. 
In most cases the operations of quantitative analysis will engage 
attention. These should be of a volumetric and gravimetric 
character; for details concerning them see the following pages. 
QUANTITATIVE ANALYSIS. 
INTRODUCTORY REMARKS. 
General Principles.—The proportions in which chemical sub- 
stances unite with each other in forming compounds are definite 520 
QUANTITATIVE ANALYSIS. 
and invariable (p. 47). Quantitative analysis is based on this law. 
When, for example, aqueous solutions of a salt of silver and a chlo- 
ride are mixed, a white curdy precipitate is produced containing 
chlorine and silver in atomic proportions; that is, 35.4 parts of chlo- 
rine to 107.7 of silver. No matter what the chloride or what the 
salt of silver, the resulting chloride of silver is invariable in compo- 
sition. The formula AgOl is a convenient picture of this compound 
in these proportions. The weight of a definite compound being 
given, therefore, the proportional amounts of its constituents can 
be ascertained by simple calculation. Suppose, for instance, 8.53 
parts of chloride of silver have been obtained in some analytical 
operation; this amount will contain 2.11 parts of chlorine and 6.42 
of silver; for if 143.1 (the molecular wrnight) of chloride of silver 
contain 35.4 (the atomic weight) of chlorine, 8.53 of chloride of sil- 
ver will be found to contain 2.11 of chlorine:— 
143.1 : 35.4 : : 8.53 : 
8.53 
1.062 
17.70 
283.2 
143.1)301.962(2.11 
286.2 
15.76 
14.31 
.1.452 
i.431_ 
21 a: = 2.11. 
And if 143.1 of chloride of silver contain 107.7 of silver, 8.53 of 
chloride of silver will contain very nearly 6.42 of silver. To ascer- 
tain, for example, the amount of silver in a substance containing, 
say, nitrate of silver, all that is necessary is to take a weighed quan- 
tity of the substance, dissolve it, precipitate the whole of the silver 
by adding hydrochloric acid or other chloride till no more chloride of 
silver falls, collect the precipitate on a filter, wash, dry, and weigh. 
The amount of silver in the dried chloride, ascertained by calcula- 
tion, is the amount of silver in the quantity of substance on which 
the operation was conducted; a rule-of-three sum gives the quantity 
per cent., the form in which the results of quantitative analysis are 
usually stated. Occasionally a constituent of a substance admits of 
being isolated and weighed in the uncombined state. Thus the 
amount of mercury in a substance may be determined by separating 
and weighing the mercury in a metallic condition ; if occurring as 
calomel (IlgCl) or corrosive sublimate (IIgCl2), the proportion of 
chlorine may then be ascertained by calculation (Ilg = 199.7; 
Cl = 35.4). 
Nature of Gravimetric Quantitative Analysis.—As above stated, 
a body may be isolated and weighed, and its quantity thus ascertained, 
or it may be separated and weighed in combination with another body DETERMINATION OF ATMOSPHERIC PRESSURE. 
521 
whose combining proportion is well known; this is quantitative anal- 
ysis by the gravimetric method. 
Nature of Volumetric Quantitative Analysis.—Volumetric opera- 
tions depend for success on some accurate initial gravimetric opera- 
tion. A weighed amount of a pure salt is dissolved in a given volume 
of water or other fluid, and thus forms a standard solution. Accu- 
rately measured quantities of such a solution will obviously contain 
just as definite amounts of the dissolved salt as if those amounts were 
actually weighed in a balance, and, as measuring occupies less time 
than weighing, the volumetric operations can be conducted with great 
economy of time as compared with the corresponding gravimetric 
operations. Quantitative analysis by the volumetric method consists 
in noting the volume of the standard liquid required to be added to 
the substance under examination before a given effect is produced. 
Thus, for instance, a solution of nitrate of silver of known strength 
may be used in experimentally ascertaining an unknown amount of 
chlorine in any substance. The silver solution is added to a solu- 
tion of a definite quantity of the substance until flocks of chloride 
of silver cease to be precipitated : every 107.7 parts of silver added (or 
169.7 of nitrate of silver: Ag= 107.7, N = 14, 03 —48; total 169.7) 
indicates the presence of 35.4 of chlorine or an equivalent quantity 
of any chloride. The preparation of standard solutions, such as 
that of nitrate of silver, to which allusion is here made, requires 
considerable care, but when made certain analyses can, as already 
indicated, be executed with far more rapidity and ease than by 
gravimetric processes. 
Quantitative Determination of (a) Atmospheric Pressure, (5) Tem- 
perature, and (c) Weight.—The quantitative analysis of solids and 
liquids often involves quantitative determinations of atmospheric 
pressure, temperature, and weight. These processes will now be 
explained, after which an outline of volumetric and gravimetric 
quantitative analysis will be given. The scope of this work pre- 
cludes any attempt to describe all the little mechanical details ob- 
served by quantitative analysts • essential operations, however, arc 
so fully treated that expert manipulators will meet with little 
difficulty. 
Quantitative Determination of Atmospheric Pressure. 
The Barometer.—The analysis of gases and vapors involves de- 
terminations of the varying pressure of the atmosphere as indicated 
by the barometer (from (3apoc, baros, weight, and yerpov, metron, 
measure). 
The ordinary mercurial barometer is a glass tube 33 or 34 inches 
long, closed at one end, filled with mercury, and inverted in a small 
cistern or cup of mercury (fig. 62). The mercury remains in the 
tube, owing to the weight or pressure of the atmosphere on the ex- 
posed surface of the liquid, the average height of the column being 
nearly 30 inches. In the popular form of the instrument, the wheel- 
barometer, the cistern is formed by a recurvature of the tube (fig. 
63); on the exposed surface of the mercury a float is placed, from 
which a thread passes over a pulley and moves an index whenever 522 
QUANTITATIVE ANALYSIS. 
the column of mercury rises or falls. As supplied to the public, 
these barometers are usually enclosed in ornamental frames with 
thermometers attached. In the wheel- 
barometer the glass tube and contained 
column of mercury are altogether en- 
closed, the index alone being visible. 
In the other variety the upper end of 
the glass tube and mercurial column 
are exposed, and the height of the 
mercury is ascertained by direct ob- 
servation. 
The aneroid barometer (from a, a, 
without, and vr/goq, neros, fluid) con- 
sists of a small, shallow, vacuous metal 
drum, the sides of which approach 
each other when an increase of atmo- 
spheric pressure occurs, their elasticity 
enabling them to recede toward their 
former position on a decrease of pres- 
sure. This motion is so multiplied 
and altered in direction by levers, etc. 
as to act on a hand traversing a plate 
on which are marked numbers corre- 
sponding Avith those showing the height 
of the mercurial column of the ordi- 
nary barometer by wdiich the aneroid 
wars adjusted. The Bourdon barometer 
(from the name of the inventor) is a 
modified aneroid, containing, in the 
p'ace of the round metal box, a flat- 
tened vacuous tube of metal bent nearly to a circle. These barom- 
ters are also useful for measuring the pressure in steam-boilers, etc. 
Under the name of pressure-gauges they are sold to indicate pres- 
sure of 500 pounds and upward per square inch. From their porta- 
bility (they can be made of 1 to 2 inches in diameter and 1 inch 
thick) they are excellent companions for travellers wishing to know 
the height of hills, mountains, and other elevations. 
For further information concerning the influence of pressure on 
the volume of a gas or vapor see page 547 ; and for descriptions of 
the methods of analyzing gases refer to Ganot's Physics (translated 
by Atkinson), Miller’s Chemical Physics, and “ Analysis of Gases ” 
in Watt's Dictionary of Chemistry. 
Fig. 62. 
Fig. 63. 
Barometer. 
Barometer, 
Quantitative Determination of Temperature. 
General Principles.—As a rule, all bodies expand on the addition 
and contract on the abstraction of heat, the alteration in volume 
being constant and regular for equal increments or decrements of 
temperature. The extent of this alteration in a given substance, 
expressed in parts or degrees, constitutes the usual method of in- 
telligibly stating, with accuracy, precision, and minuteness, a par- 
ticular condition of warmth or temperature—that is, of sensible TEMPERATURE. 
523 
heat. The substance commonly employed for this purpose is mer- 
cury, the chief advantages of which are that it will bear a high tem- 
perature without boiling, a low temperature without freezing, does 
not adhere to glass to a sufficient extent to “wet” the sides of any 
tube in which it may be enclosed, and, from its good conducting- 
power for heat, responds rapidly to changes of temperature. Plati- 
num, earthenware, alcohol, and air are also occasionally used for 
thermometric purposes. 
The Thermometer.—The construction of an accurate ther- 
mometer is a matter of great difficulty, but the following are 
the leading steps in the operation :—Select a piece of glass 
tubing having a fine capillary (capillus, a hair) bore and about 
a foot long ; beat one extremity in the blowpipe-flame until the 
orifice closes and the glass is sufficiently soft to admit of a 
bulb being blown ; heat the bulb to expel air, immediately 
plunging the open extremity of the tube into mercury ; the 
bulb having cooled, and some mercury having entered and 
taken the place of expelled air, again heat the bulb and tube 
until the mercury boils and its vapor escapes through the bore 
of the tube : again plunge the extremity under mercury, which 
will probably now completely fill the bulb and tube. When 
cold the bulb is placed in melting ice. The top of the column 
of mercury in the capillary tube should then be within an inch 
or two of the bulb ; if higher, some of the mercury must be 
expelled by heat; if lower, more metal must be introduced as 
before. The tube is now heated near the open end and a por- 
tion drawn out until the diameter is reduced to about one- 
tenth. The bulb is next warmed until the mercurial column 
rises above the constricted part of the tube, which is then 
rapidly fused in the blowpipe-flame and the extremity of the 
tube removed. 
The instrument is now ready for graduation. The bulb is 
placed in boiling water (a medium having, cseteris paribus, an 
invariable temperature), and when the position of the top of 
the mercurial column is constant a mark is made on the tube 
by a scratching diamond or a file. This operation is repeated 
with melting ice (also a medium having an invariable tempe- 
rature). The space between these two marks is divided into a 
certain number of intervals termed degrees. Unfortunately, 
this number is not uniform in all countries: in England it is 
180, as proposed by Fahrenheit; in France 100, as proposed 
by Celsius (the Centigrade scale), a number generally adopted 
by scientific men ; in some parts of the Continent the divisions 
are 80 for the same interval, as suggested by Reaumur. Which- 
ever be the number selected, similar markings should be con- 524 
QUANTITATIVE ANALYSIS. 
tinued beyond the boiling- and freezing-points as far as the 
length of the stem admits. They may be made on the stem 
itself or on any wood, metal, or 
earthenware frame on which the 
stem is mounted. 
Thermometric Scales (fig. 64).— 
On the Centigrade (C.) and Reau- 
mur (R.) scales the freezing-point of 
water is made zero, and the boiling- 
point 100 and 80 respectively ; on 
the Fahrenheit (F.) scale the zero 
is placed 32 degrees below the con- 
gealing-point of water, the boiling- 
point of which becomes, consequent- 
ly, 212. Even on the Fahrenheit 
system, temperatures below the 
freezing-point of water are often 
spoken of as “degrees of frost;” 
thus 19 degrees as marked on the 
thermometer would be regarded as 
“ 13 degrees of frost.” It is to be 
regretted that the freezing-point of 
water is not universally regarded 
as the zero-point, and that the number of intervals between that and 
the boiling-point is not everywhere the same. 
The degrees of one scale are easily converted into those of another 
if their relations be remembered—namely: 180 (F.), 100 (C.), 80 
(R.); or 18, 10, and 8 ; or, best, 9, 5, and 4. 
Fig. 64, 
Thermometric Scales. 
Fahrenheit. Centigrade. 
Reaumur. 
Formulae for the Conversion of Degrees of one Thermometric Scale 
into those of another. 
F = Fahrenheit. 
R = Reaumur. 
O = Centigrade. 
D = The observed degree. 
If above the freezing-point of water (32° F ; 0° C ; 0° R), 
F into C (D — 32) -+- 9 X 5. 
F “ R (D — 32) + 9X4. 
C “ F • D + 5 X 9 + 32. 
R “ F D 4 X 9 + 32. 
If below freezing, but above 0° F (— 17°.77 C ; — 14°.22 R), 
F into C — (32 — D) + 9 X 5. 
F “ R — (32 — D) + 9 X 4. 
C “ F 32 — (1) + 5 X 9. 
R “ F ..... . 32 — (D + 4X9. 
If below 0° F (— 17°.77 C; — 14°.22 R), 
F into C — (D + 32) -s- 9 X 5. 
F “ 11 — (I) + 32) -+- 9 X 4. 
C “ F -([)+ 5 X9)- 32. 
R “ F — (D -+- 4 X 9) — 32. THERMOMETRIC SCALES. 
525 
For all degrees: 
C into K D -f 5 X 4. • 
11 “ C D h- 4 X 5. 
In ascertaining the temperature of a liquid the bulb of a 
thermometer is simply inserted and the degree noted. In de- 
termining the boiling-point also the bulb is inserted in the 
liquid, if a pure substance. In taking the boiling-point of a 
liquid which is being distilled from a mixture, the bulb of the 
thermometer should be near to but not beneath the surface. 
The “ boiling-point ” of a liquid is the temperature at which 
the elasticity of the vapor of the substance overcomes the 
atmospheric or other pressure to which the liquid is exposed. 
If the pressure is equal to 760 mm. (29.92 inches) of mercury, 
water will boil at 100° C. (212° F.). The boiling-point of a 
drop of a fluid is taken by introducing it into the closed ex- 
tremity of a small U-tube, the remaining portion of the closed 
limb being filled with mercury. The tube is lowered into a 
bath, the open limb being above the surface of the fluid of the 
bath. The bath is slowly and equally heated, and the boiling- 
point of the liquid, indicated by the mercury falling until it is 
level in the two limbs, taken by a thermometer whose bulb is 
close to the U-tube. 
The following are the boiling-points of a few substances met 
with in pharmacy :— 
Centigrade. 
Fahrenheit. 
Alcohol, absolute 
78.3 
173 
“ 84 per cent 
79.5 
175 
“ 49 per cent, (proof spirit) . . . 
81.4 
178.5 
u ainylic 
132.2 
270 
Benzol 
80.6 
177 
Bromine 
63.0 
145.4 
Benzoic acid 
239.0 
462 
Carbolic acid 
187.8 
370 
Chloroform 
61 
142 
Ether (B. P.) (below) 
40.5 
105 
“ pure 
35 
95 
Mercury in vacuo (as in a thermometer) 
“ in air (barom. at 30 inches) . . . 
304 
580 
350 
662 
Water (barom. at 29.92 inches) .... 
“ ( “ 29.33 “ ) . . . . 
100 
212 
99.5 
211 
“ ( “ _ 28.74 “ ) . . . . 
Saturated solutions of— 
99 
210 
Cream of tartar 
101 
214 
Common salt 
106.6 
224 
Sal ammoniac 
113.3 
236 
Nitrate of sodium 
119 
246 
Acetate of sodium 
124.4 
256 
Chloride of calcium 
179.4 
355 526 
QUANTITATIVE ANALYSIS. 
By “ gentle heat,” U. S. P., is meant any temperature between 
about 32° C. ami 38° C. (about 90° and 100° F.). 
To Determine Melting-points of Fat,—Heat a fragment of 
the substance (spermaceti or wax, for example) till it liquefies, 
and then draw up a small portion into a thin glass tube about 
the size of a knitting-needle. Immerse the tube in cold water 
contained in a beaker, and slowly heat the vessel till the thin 
opaque cylinder of solid fat melts and becomes transparent; a 
delicate thermometer placed in the water indicates the point of 
change to the fifth of a degree. Remove the source of heat 
and note the congealing-point of the substance ; it will be iden- 
tical with or close to the melting-point. 
Pyrometers.—Temperatures above the boiling-point of mer- 
cury are determined by ascertaining to what extent a bar of 
platinum or porcelain has elongated. The bar is enclosed in a 
cavity of a suitable case, a plug of platinum or porcelain placed 
at one end of the bar, and the whole exposed in the region the 
temperature of which is to be found. After cooling, the dis- 
tance to which the bar has forced the plug along the cavity is 
accurately measured and the corresponding degree of tempera- 
ture noted. The value of the distance is fixed for low tempe- 
ratures by comparison with a mercurial thermometer, and the 
scale carried upward through intervals of equivalent length. 
Such thermometers are conventionally distinguished from ordi- 
nary instruments by the name pyrometer (from -up, pur, fire, 
and pirpov, metron, measure). 
The following are melting-points of substances official in the 
British Pharmacopoeia :— 
Acetic acid, glacial 
In degrees 
Centigrade. 
8.9 
In degrees 
Fahrenheit. 
48 
u u u 
congeals at . . 
1.1 
34 
Penzoic acid 
120 
248 
Carbolic acid . . 
35 
95 
Oil of theobroma . 
. (about) 
32 
90 
Phosphorus 
43.3 
110 
Prepared lard . 
. . . (about) 
38 
100 
“ suet . . 
39.5 
103 
Spermaceti . . . 
. (not under) 
38 
100 
White wax . 
65.5 
150 
Yellow wax 
GO 
140 
The order of fusibility of a few of the metals is as fol- 
lows:— MELTING-POINTS. 
527 
Mercury .... 
In degrees 
Centigrade. 
—39.4 
In degrees 
Fahrenheit. 
— 39 
Potassium .... 
+ 62.5 
+ 144.5 
Sodium 
97.6 
207.7 
Tin 
227.8 
442 
Bismuth .... 
264 
507 
Lead 
325 
617 
Zinc 
411.6 
773 
Antimony .... 
621 
1150 
Silver . 
1023 
1873 
Copper ..... 
Gold 
. . . . . 1091 
1996 
1102 
2016 
Cast iron .... 
1530 
2786 
QUESTIONS AND EXERCISES. 
922. On what fundamental laws are the operations of quantitative 
analysis based ? 
923. What is the general nature of gravimetric quantitative 
analysis ? 
924. Describe the general principle of volumetric quantitative 
analysis. 
925. How are variations in atmospheric pressure quantitatively 
determined ? 
926. Explain the construction and mode of action of a mercurial 
barometer. 
927. In what respect does a wheel-barometer differ from an instru- 
ment in which the readings are taken from the top of the column of 
mercury ? 
928. Describe the principle of action of an aneroid barometer. 
929. On what general principles are thermometers constructed? 
930. What material is employed in making thermometers? 
931. Why is mercury selected as a thermometric indicator? 
932. Describe the manufacture of a mercurial thermometer. 
933. How are thermometers graduated? 
934. Give formulm for the conversion of the degrees of one ther- 
mometric scale into those of another, (a) when the temperature is 
above the freezing-point of water, {!>) below 32° F., but above 0° F., 
and (c) below 0°. 
935. Name the degree C. equivalent to 60° F. 
936. What degree C. is represented by — 4° F. ? 
937. Mention the degree F. indicated by 23° C. 
938. Convert 100° R. into degrees C. and F. 
939. State the boiling-points of alcohol, chloroform, ether, mer- 
cury, and water on either thermometric scale. 
940. Describe the details of manipulation in estimating the melt- 
ing-point of fats. 
941. In what respect do pyrometers differ from thermometers? 528 
QUANTITATIVE ANALYSIS. 
942. Mention the melting-points of glacial acetic acid, oil of theo- 
broma, lard, suet, and wax. 
943. Give the fusing-points of tin, lead, zinc, copper, and cast- 
iron. 
Quantitative Determination of Weight. 
Definitions. 
All bodies, celestial and terrestrial, attract each other, the amount 
of attraction being in direct proportion to the quantity of matter of 
which they consist, and in inverse proportion to the squares of their 
distances. This is gravitation. When gravitation in certain direc- 
tions is exactly counterbalanced by gravitation in opposite directions, 
a body {e. g. the earth) remains suspended in space. Such a body 
in relation to other bodies has gravity, but not weight. Weight is 
the effect of gravity, being the excess of gravitation in one direction 
over and above that exerted in the opposite direction. Weight, 
truly, in any terrestrial substance is the excess of attraction which 
it and the earth have for each other over and above the attraction 
of each in opposite directions by the various heavenly bodies. But, 
practically, the weight of any terrestrial substance is the effect of 
the attraction of the earth only. Specific weight is the definite or 
precise weight of a body in relation to its bulk ; it is more usually 
but not quite correctly termed specific gravity—gravity belonging to 
the earth, and not, in any sensible degree, to the substance. 
QUESTIONS. 
944. What is understood by gravitation ? 
945. State the difference between weight and gravity. 
946. Mention a case in which a body has gravity, but no apparent 
weight. 
947. Practically, what causes the weight of terrestrial substances? 
Weights and Measures. 
The Balance.—The balance used in the quantitative operations of 
analytical chemistry must be accurate and sensitive. The points of 
suspension of the beam and pans should be polished steel or agate 
knife-edges working on agate planes. It should turn easily and 
quickly, without too much oscillation, to or of a grain or 
T\y of a milligramme, when 1000 grains or 50 or 60 grammes are 
placed in each scale. (Grammes are weights of the metric system, 
a description of which is given on the next two or three pages.) The 
beam should be light and strong, capable of supporting a load of 
1500 grains or 100 grammes; its oscillations are observed by help 
of a long index attached to its centre, and continued downward for WEIGHTS AND MEASURES. 
529 
some distance in front of the supporting pillar of the balance. The 
instrument should be provided with screws for purposes of adjust- 
ment, a mechanical contrivance for supporting the beam above its 
bearing when not in use or during the removal or addition of 
weights, spirit-levels to enable the operator to give it a horizontal 
position, and be enclosed in a glass case to protect from dust. It 
should be placed in a room the atmosphere of which is not liable to 
be contaminated by acid fumes, in a situation free from vibration, 
and a vessel containing lumps of quicklime should be placed in the 
case to keep the enclosed air dry and prevent the formation of rust 
on any steel knife-edges or other parts. During weighing the doors 
of the balance should be shut, in order that currents of air may not 
unequally influence the pans. 
The Weights.—These should be preserved in a box having a sep- 
arate compartment for each. They must not be lifted directly with 
the fingers, but by a small pair of forceps. If grain-weights, they 
should range from 1000 grs. to y gr., a weight being fashioned 
of gold wire to act as a “ rider ” on the divided beam, and thus in- 
dicate by its position lOOths and lOOOths of a grain. From to 
10 grs. the weights may be of platinum ; thence upward, to 1000 
grs., of brass. The relation of the weights to each other should be 
decimal. Metric decimal weights may range from 1000 grammes to 
1 gramme of brass, and thence downward to 1 centigramme of plat- 
inum, a gold centigramme rider being employed to indicate milli- 
grammes and tenths of a milligramme. 
Weights and Measures of the TJ. S. Pharmacopoeia.—“The 
working formulae of the United States Pharmacopoeia are now so 
constructed that, in their practical application, any system of 
weights or (in certain cases measures) may be used.” “ The 
weights and measures referred to by physicians in prescribing, 
and used by pharmacists in dispensing medicines, are, in the 
United States, either those of the “ apothecaries’ or troy system of 
weights and the wine measure, or those of the metric system.” 
Troy Weights.—These are derived from the troy pound, and are 
exhibited in the following table, with their signs annexed:— 
One pound, lb = 12 ounces = 5760 grains. 
One ounce, =? 8 drachms — 480 grains. 
One drachm, ,5 = 3 scruples = 60 grains. 
One scruple, = 20 grains. 
One grain, gr = 1 grain. 
It is highly important that persons engaged in preparing med 
icines should be provided with troy weights. But those who are 
not so provided can make their avoirdupois weights available as 
substitute for troy weights by bearing in mind that 42.5 grains, 
added to the avoirdupois ounce, will make it equal to the troy 
ounce, and that 1240 grains, deducted from the avoirdupois pound, 
will reduce it to the troy pound. 
Measures.—These are derived from the wine gallon, and are given 
in the following table, with their signs annexed:— 530 
QUANTITATIVE ANALYSIS. 
One gallon, C = 8 pints = 61,440 minims. 
One pint, 0 = 16 lluidounces = 7,680 minims. 
One iiuidounce, — 8 fluidrachms = 480 minims. 
One fluidrachm, f3 = 60 minims. 
One minim, n\, = 1 minim. 
Relation of Troy Weight and Wine Measure. 
1 minim — 0.95 grains. 
1 fg = 56.96 " “ 
1 fg = 455.69 “ 
1 grain = 1.05 minims. 
1 3 = 6 3.2 “ 
1 | = 505.6 “ 
The Metric System of weights (the word metric is from the 
Greek yergov, metron, measure) is greatly to be preferred to all 
others, the relation of the metric weights of all denominations to 
measures of length, capacity, and surface being so simple as to be 
within the perfect comprehension of a child ; while under the Brit- 
ish and American plans the weights have no such relation either 
with each other or with the various measures. Moreover, the metric 
system is in perfect harmony with the universal method of counting 5 
it is a decimal system. 
[It is perhaps impossible to realize, much more express, the ad- 
vantages we enjoy from the fact that in every country of the world 
the system of numeration is identical. That system is the decimal. 
Whatever language a man speaks, his method of numbering is deci- 
mal ; his talk concerning number is decimal; his written or printed 
signs signifying number are decimal. With the figures, 1, 2, 3, 4, 5, 
0, 7, 8, 9, 0 he represents all possible variation in number, the posi- 
tion of a figure in reference to its companions alone determining its 
value, a figure on the left hand of any other figure in an allocation 
of numeral symbols (for example, 1871) having ten times the value 
of that figure, while the figure on the right hand of any other has a 
tenth of the value of that other. When the youngest pupil is asked 
how many units there are in 1871, he smiles at the simplicity of the 
question, and says 1871. How many tens? 187, and 1 over. How 
many hundreds? 18, and 71 over. How many thousands? 1, and 
871 over. But if he is asked how many scruples there are in 1871 
grains, how many drachms, how many ounces, he first inquires 
which drachms or which ounces are. meant—avoirdupois ounces, 
troy ounces, or wine ounces—and then brings out his slate and 
pencil. And so with the pints or gallons in 1871 fluidounces, or 
the feet and yards in 1871 inches, or the pence, shillings, and 
pounds in 1871 farthings-, to say nothing of cross questions, such 
as the value of 1871 articles at 2 dollars and 20 cents per dozen, or 
of the perplexity caused by the varying values of several individual 
weights or of measures of length, capacity, and surface in different 
parts of the country. What is desired is, that there should be an 
equally simple decimal relation among weights and measures and 
coins as already universally exists among numbers. This condition 
of things having already been introduced into most other countries, 
there is no good reason why it should not be accomplished in the 
United States and Great Britain.] WEIGHTS AND MEASURES. , 
531 
The Metric System of weights and measures is founded on the 
metre. The engraving (Fig. 05) represents a pocket folding-meas- 
Fig. 65. 
ure, the tenth part of a metre in length, divided into ten centimetres, 
and each centimetre into 10 millimetres. 
The units of the system with their multiples and submultiples 
are as follows :— 
The Decimetre. 
Length.—The Unit of Length is the Metre, derived from the 
measurement of the quadrant of a meridian of the earth. (Prac- 
tically, it is the length of certain carefully-preserved bars of metal 
from which copies have been taken.) 
Surface.—The Unity of Surface is the Are, which is the square 
of ten metres. 
Capacity.—The Unity of Capacity is the Litre, which is the cube 
of a tenth part of a metre. 
Weight.—The Unit of Weight is the Gramme, Avhich is the weight 
of that quantity of distilled water, at its maximum density (4° C.), 
which fills a cube of the one-hundredth part of the metre. 
Units. 
Table. 
Note.—Multiples are denoted by the Greek words “ Deca,” Ten, 
“ llecto,” Hundred, “ Kilo,” Thousand. 
Subdivisions, by the Latin words “ Deci,” One-tenth, “ Centi,” 
One-hundredth, “ Milli,” One-thousandth. 
Quantities. 
Length. 
Surface. 
Capacity. 
Weight. 
1000 
Kilo-metre 
Kilo-litre 
Kilo-gramme. 
100 
Hecto-metre 
Hectare 
Hecto-litre 
Hecto-gramme. 
10 
Deca-metre 
Deca-litre 
Deca-gramme. 
1 (Uni 
ts) METRE 
ARE 
LITRE 
GRAMME. : 
.1 
Deci-metre 
'Deci-litre 
Deci-gramme. 
.01 
Centi-metre 
Centiare 
Centi-litre 
Centi-gramme. 
.001 
Milli-metre 
. . 
Milli-litre 
Milli-gramme. 
When the Metric Method is exclusively adopted these units and this 
table, comprising the entire system of weights and measures, repre- 
sent all that will be essential to be learned in lieu of the numerous 
and complicated tables hitherto in use. Adopting the style of ele- 
mentary books on arithmetic, the Tables may be expanded in the 
following manner:— 532 
QUANTITATIVE ANALYSIS. 
10 Milligrammes make 1 Centigramme. 
10 Centigrammes u 1 Decigramme. 
10 Decigrammes “ 1 Gramme. 
10 Grammes “ 1 Decagramme. 
10 Decagrammes “ 1 Hectogramme, 
10 Hectogrammes “ 1 Kilogramme. 
10 Millilitres make 1 Centilitre, 
etc. 
10 Millimetres make 1 Centimetre, 
etc. 
The following approximate equivalents of metrical units should 
be committed to memory:— 
1 Metre = 3 feet 3 inches and 3 eighths. 
1 Are = a square whose side is 11 yards. 
1 Litre = If pints. 
1 Gramme = 15£ grains. 
The Kilometre is equal to 1100 yards. 
The Hectare = 2£ acres nearly. 
The Metric Ton of 1000 Kilogrammes = 19 cwt. 2 qrs. 20 lbs. 10 oz. 
The Kilogramme = 2 lbs. oz. nearly. 
For exact equivalents in many forms see pages 539 and 540. A 
litre of water at 39° F. weighs 15432 grains; at 50° F., 15429 
grains; at 60° F., it weighs 15418 grains; at 70° F., 15403 grains; 
and at 80° F., 15383 grains (File). (The word gramme is, in Eng- 
lish, frequently written gram.) 
Decimal Coinage.—In most countries where the metric system of 
weights and measures is employed a decimal division of coins is also 
adopted. This course, conjoined with the ordinary decimal method 
of enumerating, which, fortunately, is in universal use, renders cal- 
culations of all kinds most simple—easy to an extent which cannot 
be conceived in countries like England, where the operations of 
weighing, measuring, paying, and counting have only the most ab- 
surdly intricate relations to each other. 
The General Council under whose authority the British Pharma- 
copoeia is issued encourages medical practitioners and pharmacists 
in the adoption of the metric system, and gives the annexed state- 
ment of metric weights and measures:— WEIGHTS AND MEASURES. 
533 
EIGHTS AND MEASURES OF THE 
METRICAL SYSTEM. 
(From the British Pharmacopoeia of 1867.) 
Weights. 
I Milligramme = the thousandth part of one grm., or 0.001 grm. 
I Centigramme = the hundredth “ 0.01 “ 
1 Decigramme = the tenth “ 0.1 “ 
1 Gramme = weight of a cubic centimetre of 
water at 4° C. 1.0 “ 
1 Decagramme — ten grammes 10.0 “ 
1 Hectogramme = one hundred grammes 100.0 u 
1 Kilogramme = one thousand grammes 1000.0 (1 kilo.). 
Measures of Capacity. 
1 Millilitre = 1 cub. centim., or the meas. of 1 gram, of water. 
1 Centilitre = 10 “ “ 10 “ “ 
1 Decilitre = 100 “ “ 100 “ “ 
1 Litre = 1000 “ “ 1000 “ (1 kilo.). 
Measures of Lexgtii. 
1 Millimetre = the thousandth part of one metre, or 0.001 metre. 
1 Centimetre = the hundredth “ 0.01 “ _ 
1 Decimetre — the tenth “ 0.1 “ 
1 Metre = the ten-millionth part of a quarter of the meridian 
of the earth. 
The National Convention for revising the Pharmacopoeia of the 
United States also recognizes the metric system of weights and 
measures by giving, in the recent (sixth) edition of the Pharma- 
copoeia, Tables of the units of the metrical system with their mul- 
tiples and submultiples, similar to the foregoing, and the following 
Tables showing the relation to each other of the metrical and troy 
systems. In some parts of the text of the work the metric system 
is that actually employed. 
TABLES OF WEIGHTS AND MEASURES. 
A.—MEASURES OF LENGTH. 
I. Relation of Metric to United States Measures of Length. 
1 Metre = 39.370432 inches. 
1 Decimetre == 3.937043 “ 
1 Centimetre — 0.393704 “ 
1 Millimetre = 0.039370 “ QUANTITATIVE analysis. 
11. Relation of United States to Metric Measures of Length. 
1 Yard (or 36 Inches) — 0.91439 Metre. 
1 Foot (or 12 Inches) = 30.40 Centimetres. 
Inches. Centimetres. 
11 = 27.9 
10 = 25.4 
9 = 22.9 
8 = 20.3 
7 = 17.8 
6 = 15.2 
Inches. Centimetres. 
5 - 12.7 
4 = 10.2 
3 = 7.6 
2 = 5.1 
1 = 2.5 
Inch. Centimetres 
A = 12.5 
| = 6.25 
£ = 3.12 
rV = 1-^4 
To = 1-00 
B.—MEASURES OF CAPACITY. 
Cubic Centim. Fluidounces. 
1,000 = 33.81 
950 = 32.12 
900 = 30.43 
850 = 28.74 
800 = 27.05 
750 25.36 
700 = 23.67 
650 = 21.98 
600 = 20.29 
550 = 18.59 
500 = 16.90 
450 =; 15.22 
400 = 13.53 
350 = 11.84 
300 = 10.14 
250 a# 8.45 
200 = 6.76 
150 = 5.07 
100 = 3.38 
30 = 1.01 
Cubic Centim. Fluidrachms. 
25 = 6.76 
20 = 5.41 
III. Relation of Metric to United States Fluid Measures. 
Cubic Centim. Fluidrachms. 
15 = 4.06 
10 = 2.71 
9 = 2.43 
8 = 2.16 
7 = 1.89 
6 = 1.62 
5 = 1.35 
4 = 1.08 
; Cubic Centim. Minims. 
i 3 = 48.69 
i 2 = 32.46 
1 = 16.23 
0.95 = 15.42 
0.90 = 14.61 
0.85 = 13.80 
0.80 = 12.98 
0.75 = 12.17 
0.70 = 11.36 
0.65 = 10.55 
0.60 = 9.74 
0.55 = 8.93 
0.50 = 8.12 
0.45 = 7.30 
Cubic Centim. Minims 
0.40 = 6.49' 
0.35 = 5.68 
0.30 = 4.87 
0.25 = 4.06 
0.20 = 3.25 
0.19 = 3.08 
0.18 = 2.92 
0.17 = 2.76 
0.16 = 2.60 
0.15 = 2.43 
0.14 == 2.27 
0.13 = 2.11 
0.12 == 1.95 
0.11 = 1.79 
0.10 = 1.62 
0.09 .= 1.46 
0.08 = 1.30 
0.07 = 1.14 
0.06 = 0.97 
0.05 = 0.81 
0.04 = 0.65 
0.03 = 0.49 
0.02 = 0.32 
0.01 = 0.16 
Minims. Cubic Centim. 
1 = 0.06 
2 = 0.12 
3 = 0.18 
4 = 0.25 
5 = 0.31 
6 = 0.37 
7 = 0.43 
IY. Relation of United States to Metric Fluid Measures. 
Minims. Cubic Centim. 
8 = 0.49 
9 = 0.55 
10 = 0.62 
11 = 0.68 
12 = 0.74 
13 = 0.80 
14 = 0.86 
Minims. Cubic Centim 
15 = 0.92 
16 = 0.99 
17 = 1.05 
18 = 1.11 
19 = 1.17 
20 = 1.23 
21 = 1.29 WEIGHTS AND MEASURES. 
Relation of United States to Metric Fluid Measures.— Coni. 
Minims. Cubic Centim. 
22 = 1.36 
23 = 1.42 
24 =s 1.48 
25 = 1.54 
26 = 1.60 
27 = 1.66 
28 = 1.73 
29 = 1.79 
30 = 1.85 
35 = 2.16 
40 = 2.46 
45 = 2.77 
50 = 3.08 
55 = 3.39 
60 = 3.70 
70 = 4.31 
80 = 4.93 
90 = 5.54 
100 = 6.16 
110 = 6.78 
120 = 7.39 
Fluidraclims. Cubic Centim. 
I 3 = 11.09 
4 = 14.79 
5 = 18.48 
6 — 22.18 
7 = 25.88 
8 = 29.57 
9 = 33.27 
10 - 36.97 
11 = 40.66 
12 = 44.36 
13 = 48.06 
14 = 51.75 
15 = 55.45 
16 = 59.10 
Fluiduunces. 
3 = 88.67 
4 = 118.24 
5 = 147.81 
6 = 177.39 
7 = 206.96 
8 = 236.53 
9 = 266.10 
10 = 295.68 
Fluidounces. Cub. Centim. 
11 = 325.25 
12 = 354.82 
13 — 384.40 
14 = 413.97 
15 == 443.54 
16 = 473.11 
17 = 502.69 
18 = 532.26 
19 = 561.93 
20 = 591.50 
21 = 621.08 
22 = 650.65 
23 = 680.22 
24 = 709.80 
25 = 739.37 
26 = 768.94 
27 = 798.51 
28 = 828.09 
29 = 857.66 
30 = 887.23 
31 = 916.80 
32 — 946.38 
64 = 1892.75 
128 = 3785.51 
C.—WEIGHTS. 
Grammes. Grains. 
0.0010 = 0.015 
0.0013 = 0.019 
0.0015 = 0.023 
0.0020 = 0.031 
0.0025 = 0.039 
0.0030 = 0.046 
0.0035 = 0.054 
0.0040 = 0.062 
0.0045 = 0.069 
0.0050 = 0.077 
0.0055 = 0.085 
0.0060 = 0.093 
0.0065 — 0.100 
0.0070 = 0.108 
0.0075 = 0.116 
0.0080 = 0.123 
0.0085 = 0.131 
0.0090 = 0.139 
0.0095 == 0.147 
0.0100 — 0.154 
V. Relation of Metric to Apothecaries’ or Troy Weight. 
Grammes. Grains. 
0.120 = 1.852 
0.130 == 2.006 
0.140 = 2.161 
0.150 = 2.315 
0.160 — 2.469 
0.170 = 2.623 
0.180 = 2.778 
0.190 = 2.932 
0.200 = 3.086 
0.210 = 3.241 
0.220 = 3.395 
0.230 = 3.549 
0.240 = 3.704 
0.250 = 3.858 
0.260 = 4.012 
0.270 = 4.167 
0.280 = 4.321 
0.290 = 4.475 
0.300 = 4.630 
0.310 = 4.784 
Grammes. Grains. 
0.0125 = 0.193 
0.0150 = 0.231 
0.0200 = 0.309 
0.0250 = 0.386 
0.0300 = 0.463 
0.0350 = 0.540 
0.0400 = 0.617 
0.0450 = 0.694 
0.050 = 0.772 
0.055 = 0.849 
0.060 = 0.926 
0.065 = 1.003 
0.070 = 1.080 
0.075 = 1.157 
0.080 = 1.235 
0.085 = 1.312 
0.090 = 1.389 
0.095 = 1.466 
0.100 = 1.543 
0.110 == 1.698 536 
QUANTITATIVE ANALYSIS. 
Grammes. Grains. 
0.320 = 4.938 
0.330 = 5.093 
0.340 = 5.247 
0.350 = 5.401 
0.360 = 5.556 
0.370 = 5.710 
0.380 = 5.864 
0.390 = 6.019 
0.400 = 6.173 
0.500 = 7.716 
0.600 = 9.259 
0.700 = 10.803 
0.800 = 12.346 
0.900 = 13.889 
1 = 15.432 
2 = 30.865 
3 = 46.297 
4 = 61.729 
5 = 77.162 
6 = 92.594 
7 = 108.026 
8 = 123.459 
9 = 138.891 
10 = 154.323 
11 = 169.756 
12 = 185.188 
Relation of Metric to Apothecaries’ or Troy Weight.—Coni. 
Grammes. Grains. 
13 = 200.621 
14 = 216.053 
15 = 231.485 
16 = 246.918 
17 = 262.350 
18 == 277.782 
19 = 293.215 
20 = 308.647 
21 = 324.079 
22 = 339.512 
23 — 354.944 
24 = 370.376 
25 = 385.809 
26 = 401.241 
27 = 416.673 
28 = 432.106 
29 = 447.538 
30 = 462.970 
31 = 478.403 
32 = 493.835 
33 = 509.268 
34 = 524.700 
35 = 540.132 
36 = 555.565 
37 = 570.997 
38 = 586.429 
Grammes. Grains. 
39 = 601.862 
40 = 617.294 
50 = 771.617 
60 — 925.941 
70 = 1080.264 
80 = 1234.588 
90 = 1388.911 
100 = 1543.235 
125 = 1929.044 
150 = 2314.852 
200 = 3086.470 
250 = 3858.087 
300 = 4629.705 
333 = 5144.118 
350 = 5401.322 
400 = 6172.940 
450 = 6944.557 
500 = 7716.174 
600 = 9259.409 
700 = 10802.644 
750 = 11574.262 
800 = 12345.879 
900 = 13889.114 
1000 = 15432.350 
VI. Tiie Relation of Apothecaries’ (or Troy) to Metric Weight. 
Grains. Grammes. 
■h = 0.00101 
= 0.00108 
x — 0.00130 
i = 0.00135 
* = 0.00162 
1 S 0.00180 
A = 0.00202 
i = 0.00216 
= 0.00259 
X - = 0.00270 
i = 0.00324 
i = 0.00360 
i = 0.00405 
V = 0.00432 
V = 0.00540 
V = 0.00548 
i = 0.00810 
i = 0.01080 
J =; 0.01296 
Grains. Grammes. 
i = 0.01620 
£ = 0.02160 
| = 0.03240 
£ = 0.04860 
1 = 0.06480 
11- = 0.09720 
.2 = 0.12960 
2£ — 0.16200 
3 = 0.19440 
4 = 0.25920 
5 = 0.32399 
6 = 0.38879 
7 = 0.45359 
8 = 0.51839 
9 = 0.58319 
10 = 0.64799 
11 = 0.71297 
12 0.77759 
13 = 0.84239 
Grains. Grammes. 
14 = 0.90718 
15 = 0.97198 
16 = 1.037 
17 = 1.102 
18 = 1.166 
19 = 1.231 
20 = 1.296 
21 = 1.361 
22 = 1.426 
23 = 1.458 
24 = 1.555 
25 = 1.620 
26 = 1.685 
27 = 1.749 
28 = 1.814 
29 = 1.869 
30 == 1.944 
40 = 2.592 
50 = 3.240 WEIGHTS AND MEASURES. 
Relation of Apothecaries' (or Troy) to Metric 'Weight.—Cont. 
Drachms. Grammes. 
1 = 3.888 
2 = 7.776 
3 = 11.664 
4 = 15.552 
5 = 19.440 
6 = 23.328 
7 = 27.216 
Ounces. 
1 = 31.103 
Ounces. Grammes. 
14 = 46.655 
2 = 62.207 
3 = 93.310 
4 = 124.414 
5 = 155.517 
6 = 186.621 
7 = 217.724 
8 = 248.823 
9 = 279.931 
10 = 311.035 
Ounces. Grammes. 
11 = 342.138 
12 = 373.250 
13 = 404.345 
14 = 435.449 
15 = 466.552 
16 = 497.656 
17 = 528.759 
18 = 559.863 
19 = 590.966 
20 = 622.070 
VII. Relation of Metric to Avoirdupois Weight. 
Grammes. Oz. Grs. 
28.35 = 1 
29 = 1 10 
30 = 1 254 
31 = 1 41 
32 = 1 56} 
33 =1 72 
34 = 1 87} 
35 = 1 103 
36 = 1 118 
37 = 1 133J 
38 = 1 149 
39 = 1 1644 
40 = 1 180 
Avoirdupois Ounces 
and Grains. 
Grammes. Gz. Grs. 
50 = 1 334 
60 = 2 50} 
70 = 2 205 
80 = 2 359 
90 — 3 76} 
100 = 3 230} 
150 = 5 127 
200 = 7 24 
250 = 8 358 
300 = 10 255 
350 = 12 151} 
400 = 14 48 
450 = 15 382 
Avoirdupois Ounces 
and Grains. 
Grammes. Oz. Grs. 
500 = 17 279 
550 = 19 175 
600 = 21 72 
650 = 22 405} 
700 = 24 303 
750 = 26 198} 
I 800 = 28 96 
| 850 = 29 429 
900 = 31 3264 
950 = 33 222 
1000 = 35 120 
Avoirdupois Ounces 
and Grains. 
Ao°uucUer ! 
tV = 1-772, 
} 3.544 
i = 7.088 
} = 14.175! 
1 = 28.350 
2 = 56.699: 
3 = 85.049! 
4 = 113.398 | 
5 = 141.7481 
6 = 170.0981 
VIII. Relation of Avoirdupois to Metric Weight. 
I Avoirdupois Gralnmes. 
Ounces. 
7 = 198.447 
8 = 226.796 
9 = 255.146 
10 = 283.496 
11 = 311.846 
12 = 340.195 
13 = 368.544 
14 = 396.894 
15 = 425.243 
Avoirdupois 
Pounds. Grammes. 
1 =- 453.592 
2 = 907.18 
3 = 1360.78 
4 = 1814.37 
5 = 2267.96 
6 = 2721.55 
7 = 3175.14 
8 = 3628.74 
9 = 4082.33 
10 = 4535.92 
The following Tables, from the British Pharmacopoeia and the 
Diary of Messrs. De La Rue, will be found useful for reference:— 538 
QUANTITATIVE ANALYSIS. 
WEIGHTS AND MEASURES OF THE 
BRITISH PHARMACOPOEIA OF 18G7. 
1 Grain gr. 
1 Ounce oz. = 437.5 grains. 
1 Pound lb. = 16 ounces = 7000 “ 
Weights 
Measures of Capacity. 
1 Minim min. 
1 Fluidraehm fl. dr. = 60 minims. 
1 Fluidounce fl. oz. = 8 fluidrachms. 
1 Pint O. = 20 fluidounces. 
1 Gallon C. =8 pints. 
Measures of Length. 
1 line = inch. 
1 inch = gg seconds-pendulum. 
12 “ =1 foot. 
33 “ =3 feet = 1 yard. 
Length of pendulum vibrating seconds of mean' 
time in the latitude of London in a vacuum at 
the level of the sea 
39.1393 inches. 
(1 cubic inch of distilled water at 62° F. and 30 inches barom. = 
252.458 grains.) 
Relation of British Measures to Weights. 
1 Minim is the measure of 0.91 grain of water. 
1 Fluidraehm “ 54.68 grains of water. 
1 Fluidounce “ 1 ounce or 437.5 “ 
1 Pint “ 1.25 pounds or 8750.0 “ 
1 Gallon “ 10 pounds or 70,000.0 “ 
(Gtt. — guttce, drops. The term “ drop” indicates a quantity which 
is indefinite, and should only be used when approximativeness is 
alone desired.) 
Relation of Wine Measures to Cubic Measure. 
One Gallon — 231. Cubic Inches. 
One Pint = 28.875 Cubic Inches. 
One Fluidounce = 1.80468 Cubic Inches. 
One Fluidraehm = 0.22558 Cubic Inch. 
One Minim = 0.00375 Cubic Inch. WEIGHTS AXD MEASURES. 
539 
In English inches. 
In English feet 
= 12 inches. 
In English yards 
— 3 feet. 
In English fathoms 
- - 6 feet. 
In English miles 
= 1760 yards. 
Millimetre 
Centimetre 
Decimetre 
Metre 
Decametre 
Hectometre 
Kilometre 
Myriometre 
0.03937 
0.39371 
3.93708 
39.37079 
393.70790 
3937.07900 
39370.79000 
393707.90000 
0.003281 
0.032809 
0.328090 
3.280899 
32.808992 
328.089920 
3280.899200 
32808.992000 
0.0010936 
0.0109363 
0,1093633 
1.0936331 
10.9363310 
109.3633100 
1093.6331000 
10936.3310000 
0.0005468 
0.0054682 
0.0546816 
0.5468165 
5.4681655 
54.6816550 
546.8165500 
5468.1655000 
0.0000006 
0.0000062 
0.0000621 
0.0006214 
0.0062138 
0.0621382 
0.6213824 
6.2138244 
1 inch = 2.539954 centimetres. 1 yard = 0.9143835 metre. 
1 foot = 3.0479449 decimetres. 1 mile = 1.6093149 kilometres. 
Metrical Measures of Surface. 
In English square 
feet. 
In Eng. sq. yards 
= y square feet. 
In English poles 
=- 272.25 sq. feet. 
In English roods 
= 10890 sq. feet. 
In English acres 
= 43560 sq. feet. 
Centiare, or square metre 
Are, or 100 square metres 
Hectare, or 10,000 square metres.... 
10.764299 
1076.429934 
107642.993418 
1.196033 
119.603326 
11960.332602 
0.0395383 
3.9538290 
395.3828959 
0.0009885 
0.0988457 
9.8845724 
0.0002471 
0.0247114 
2.4711431 
1 square inch = 6.4513669 square centimetres. 1 square yard = 0.83609715 square metre or centiare. 
1 square foot = 9.2899683 square decimetres. 1 acre = 0.40467102 hectare. 
Metrical Measures op Length. 540 
quantitative analysis. 
In cubic inches. 
In cubic feet 
= 1728 
cubic inches. 
In pints 
= 34.65923 
cubic inches. 
In gallons = 8 pints 
= 277.27384 
cubic inches. 
In bushels = 8 gal- 
lons = 2218.19072 
cubic inches. 
- 
Millilitre, or cubic centimetre 
0.06103 
0.000035 
0.00176 
0.0002201 
0.0000275 
Centilitre, or 10 cubic centimetres.. 
0.61027 
0.000353 
0.01761 
0.0022010 
0.0002751 
Decilitre, or 100 cubic centimetres.. 
6.10271 
0.003532 
0.17608 
0.0220097 
0.0027512 
Litre, or cubic decimetre 
61.02705 
0.035317 
1.76077 
0.2200967 
0.0275121 
Decalitre, or centistere 
610.27052 
0.353166 
17.60773 
2.2009668 
0.2751208 
Hectolitre, or decistere 
6102.70515 
3.531658 
176.07734 
22.0096677 
2.7512085 
Kilolitre, or stere, or cubic metre... 
61027.05152 
35.316581 
1760.77341 
220.0966767 
27.5120846 
Myriolitre, or decastere 
610270.51519 
353.165807 
17607.73414 
2200.9667675 
275.1208459 
1 cubic inch = 16.386176 cubic centimetres. 1 cubic foot = 28.315312 cubic decimetres. 1 gallon = 
= 4.535926 litres. 
Metrical 
Measures of 
Weight. 
In troy ounces 
In avoirdupois lbs. 
In cwts. = 112 lbs. 
Tons = 20 cwts. = 
= 480 grains. 
= 7000 grains. 
= 784000 grains. 
15080000 grains. 
Milligramme 
0.01543 
0.000032 
0.0000022 
0.0000000 
0.0000000 
Centigramme 
0.15432 
0.000322 
0.0000220 
0.0000002 
0.0000000 
Decigramme 
1.54323 
0.003215 
0.0002205 
0.0000020 
0.0000001 
Gramme 
15.43235 
0.032151 
0.0022046 
0.0000197 
0.0000010 
Decagramme 
154.32349 
0.321507 
0.0220462 
0.0001968 
0.0000098 
Hectogramme 
1543.23488 
3.215073 
0.2204621 
0.0019684 
0.0000984 
Kilogramme 
15432.34880 
32.150727 
2.2046213 
0.0196841 
0.0009842 
Myriogramme 
154323.48800 
321.507267 
22.0462126 
0.1968412 
0.0098421 
1 grain = 0.064799 gramme. 1 troj 
oz. = 31.103496 grammes. 1 lb. avd. = 0.453593 kilogr. 1 cwt. = 50.802377 kilogrs. 
Metrical Measures of Capacity. SPECIFIC GRAVITY. 
541 
QUESTIONS AND EXERCISES. 
948. Mention some advantages of a decimal system of weights and 
measures. 
949. What is the name of the chief unit of the metric decimal 
system of weights and measures ? 
950. Mention the names of the metric units of surface, capacity, 
and weight, and state how they are derived from the unit of length. 
951. How are multiples of metric units indicated? 
952. State the designations of submultiples of metric units. 
953. How many metres are there in a kilometre? 
954. How many millimetres in a metre? 
955. How many grammes in 5 kilogrammes? 
956. How many milligrammes in 13\ grammes? 
957. In 1869 centigrammes how many grammes ? 
958. In a metre measure 5 centimetres wide and 1 centimetre 
thick, how many cubic centimetres? 
959. How many litres are contained in a cubic metre of any 
liquid ? 
960. State the British equivalent of the metre. 
961. How many square yards in an are? 
962. How many fluidounces in a litre? 
963. How many ounces in a kilogramme? 
964. Give the relation of a metric ton (1000 kilos.) to a British 
ton. 
965. How many grains are there in 1 ton ? 
966. How many ounces in 1 ton ? 
967. How many grains of water in 1 Huidrachm? 
968. How many minims in 1 pint? 
969. How many grains in 1 pint of water? 
970. Whence is the British unit of length derived? 
Specific Weight or Specific Gravity. 
The specific iceiyht of a substance is its weight in comparison with 
weights of similar bulks of other substances. This comparative 
heaviness of solids and liquids is conventionally expressed in rela- 
tion to water: they are considered as being lighter or heavier than 
water. Thus, water being regarded as unity — 1, the relative weight, 
or specific weight, of ether is represented by the figures .720 (it is 
nearly three-fourths, .750, the weight of water), oil of vitriol by 
1.843 (it is nearly twice, 2.000, as heavy as water). The specific 
weight of substances is, moreover, by generally accepted agreement, 
the weight of similar volumes at 15° C. (59° F.), except in the case 
of alcohol and wine, which are at present taken at 15.6° C. (60° F.), 
to maintain consistency with United States laws and regulations; 
for the weight of a definite volume of any substance will vary 
according to temperature, becoming heavier when cooled and lighter 
when heated, different bodies (gases excepted) differing in their rate 
of contraction and expansion. While, then, specific weight—or, 542 
QUANTITATIVE ANALYSIS. 
conventionally, specific gravity—is truly the comparative weight of 
equal bulks, the numbers which in America commonly represent 
specific gravities are the comparative weights of equal bulks at 
15° C. (59° F.), water being taken as unity.* The standard of com- 
parison for gases was formerly air, but is now usually hydrogen. 
Specific Gravity of Liquids.. 
Procure any small bottle holding from 100 to 1000 grains 
(fig. G6) and having a narrow neck; counterpoise it in a deli- 
cate balance ; fill it to about halfway up the neck with pure 
distilled water having a temperature of 15° C.; ascertain the 
weight of the water, and, for convenience, add or subtract a 
drop or two, so that the weight shall he a round number of 
grains; mark the neck by a diamond or file-point at the part 
cut by the lower edge of the curved surface of the water. 
Consecutively fill up the bottle to the neck-mark with several 
other liquids, cooled or warmed to 15° C., first rinsing out the 
bottle once or twice with a small quantity of each liquid, and 
note the weights; the respective figures will represent the 
relative weights of equal bulks of the liquids. If the capacity 
of the bottle is 10, 100, or 1000 grains, the resulting weights 
will, without calculation, show the specific gravities of the 
Fig. G6. 
Fig. 67. 
Fig. 68. 
Fig. 69. 
Specific-Gravity Bottles. 
liquids ; if any other number, a rule-of-three sum must be 
worked out to ascertain the weight of the liquids as compared 
with 1 (or 1.000) of water. Bottles conveniently adjusted to 
* The true weight of the body is its weight in air plus the weight 
of an equal bulk of air, and minus the weight of a bulk of air equal 
to the bulk of brass or other weights employed; or, in other words, 
its weight in vacuo uninfluenced by the buoyancy of the air; but such 
a correction of the weight of a body is seldom necessary, or, indeed, 
desirable. Density is sometimes improperly regarded as synonymous 
with specific gravity. It is true that the density of a body is in exact 
proportion to its specific gravity, but the former is more correctly the 
comparative bulk of equal weights, while specific gravity is the com- 
parative weight of equal bulks. SPECIFIC GRAVITY. 
543 
contain 250, 500, or 1000 grains, or 100 or 50 grammes, of 
water when tilled to the top of their perforated stopper (Fig. 
68), and other forms of the instrument (Figs. 67 and 69), are 
sold by all chemical-apparatus makers. Figure 69 is that of a 
bottle extremely useful in ascertaining the specific gravities of 
very volatile liquids. 
Verify some of the following stated specific gravities of substances 
official in the U. S. Pharmacopoeia, 1880:— 
Acid, Acetic 1.048 
“ “ dil 1.0083 
“ “ Glacial... 1.056-1.058 
“ Hydrobromic dil 1.077 
“ Hydrochloric 1.160 
11 “ dil 1.049 
“ Lactic 1.212 
“ Nitric 1.420 
“ “ dil 1.059 
“ Oleic 800-.810 
u Phosphoric 1.347 
“ & dil 1.057 
u Sulphuric 1.840 
“ “ Aromat 955 
“ “ dil 1.067 
“ Sulphurous 1.022-1.023 
JEther 750 
“ Acetic 889—.897 
u Fortior 725 
Alcohol 820 
“ dil 928 
Amyl Nitris 872-874 
Aq. Ammon 959 
“ “ Fort 900 
Bals. Peru 1.135-1.150 
Benzinum 670-.675 
Bromum 2.990 
Camphora 990-.995 
Carbonei Bisulphidum 1.272 
Cera Alba 0.965-0.975 
Cera Flava 955-.967 
Cetaceum 0.945 
Chloroform Purif. 1.485-1.490 
“ Yenali 1.470 
Copaiba 940-.993 
Creosote 1.035-1.085 
Fel Bovis 1.018-1.028 
Glycerinum 1.250 
Hydrargyrum 13.5 
Iodoformum 2.00 
Liq. Ammon. Acet 1.022 
Liq. Calcis 1.0015 
“ Ferri Acetatis 1.160 
“ “ Chloridi 1.405 
“ Citratis 1.260 
“ “ Nitratis 1.050 
“ “ Subsulph 1.555 
“ “ Tersulph 1.320 
“ Hydrarg. Nit 2.100 
“ Plumbi Subacetatis... 1.228 
“ Potassae 1.036 
“ Potassii Citratis 1.059 
u Sodae 1.059 
“ “ Chloratse 1.044 
“ Sodii Silicatis...1.300-1.400 
u Zinci Chlor 1.555 
Mel 1.101-1.105 
Oleum Adipis 0.900-0.920 
“ iEthereum 0.910 
u * i i f 1.060-1.070 
Amygd.Amar. j 1 043_1049 
“ “ Express... .914-.920 
“ Anisi 976-.990 
“ AurantiiCort 860 
“ “ Flor... .850-890 
“ Bergamii 860-.890 
“ Cajuputi 920 
“ Cari 920 
“ Caryoph 1.050 
“ Chenapodii 920 
“ Cinnamomi (Ceylon) 1.040 
“ “ (Chinese) 1.060 
“ Copaiba 890 
u Coriandri 870 
“ Cubebae 920 
u Erigerontis 850 
“ Eucalypti 900 
u Fceniculi 960 
“ Gaultheriae 1.180 
“ Gossypii Sem... .920-.930 
“ Hedeomae, 940 
“ Juniperi 870 544 
QUANTITATIVE ANALYSIS. 
Oleum Lavendulse 890 
“ _ “ Flor 890 
“ Limonis 850 
“ Lini 936 
“ Menth. Pip 900 
“ “ Virid 900 
“ Morrhuae 920-.925 
“ Myrcioe 1.040 
“ Myristieae 930 
“ Olivae 915-918 
“ Picis Liquida 970 
“ Pimentae 1.040 
“ Ricini 950-.970 
“ Rosae 860 
“ Rosmarini 900 
“ Rutae 880 
“ Sabinae 910 
“ Santali 945 
“ Sassafras 1.090 
“ Sesami 914-.923 
“ Sinapis Yol 1.017-1.021 
Oleum Succini 920 
“ Terebinthinae 855-.870 
“ Thymi 880 
l< Tiglii 940-.955 
Valerianae 950 
Petrolatum 835-.860 
Phosphorus (at 50° F.1.83 
Resina 1 070-1.080 
Sp. /Etheris Nitrosi... .823-.82S 
“ Ammoniae 810 
“ Ammoniae Aromat 885 
“ Frumenti 930-.917 
“ Vini Gallici 941-.925 
Syrupus 1.310 
Syr. Acidi Hydriodici 1.300 
Thymol 1.028 
Tinct. Ferri Acetatis 0.950 
“ “ Chloridi 0.980 
Vinum Album 990-1.010 
“ Rubrum 989-1.010 
Zineum 6.9 
Hydrometers.—The specific gravity of liquids may be ascertained 
without scales and weights by means of a hydrometer, an instru- 
ment usually of glass, having a graduated stem and a bulb or bulbs 
at the lower part. The specific gravity of a liquid is indicated by 
the depth to which the hydrometer sinks in the liquid, the zero of 
the scale marking the depth to which it sinks in pure water. Hydrom- 
eters constructed for special purposes are known under the names 
of saccharometer, galactometer, elaeometer, urinometer, alcohol- 
ometer. Hydrometers require a considerable quantity of liquid to 
fairly float them, and specific gravities observed with them are less 
delicate and trustworthy than those obtained by the balance; never- 
theless, they are exceedingly useful for many practical purposes where 
the employment of a delicate balance would be inadmissible. 
Specific Gravity of Solids in Mass. 
Weigh a piece (50 to 250 grains) of any solid substance 
heavier than water in the usual manner. Then weigh it in 
water by suspending it from a shortened balance-pan by a fine 
thread or hair and immersing in a vessel of water (Fig. 70). 
The buoyant properties of the water will cause the solid ap- 
parently to lose weight; this loss in weight is the exact weight 
of an equal hulk of water. The weight of the substance and 
the weight of an equal bulk of water being thus ascertained, 
a rule-of-three sum shows the proportional weight of the sub- 
stance to 1.000 of water. To express the same thing by rule, 
divide the weight in air by the loss of weight in water; the SPECIFIC GRAVITY. 
545 
resulting number is the specific gravity in relation to 1 part of 
water, the conventional standard of comparison. 
Fig. 70. 
Weighing a Solid in Water. 
Aluminium 2.56 
Antimony 6.71 
Bismuth 9.83 
Coins, English, gold 17.69 
“ “ silver 10.30 
“ “ bronze 8.70 
Copper 8.95 
Gold 19.34 
Iron 7.84 
Verify some of the following specific gravities :— 
Lead 11.36 
Magnesium 1.74 
Marble *2.70 
Phosphorus 1.77 
Platinum 21.53 
Silver 10.53 
Sulphur 2.05 
Tin 7.29 
Zinc 7.14 
Specific gravities of solid substances should be taken in water 
having a temperature of about 15° C. (59° F.). The body should be 
immersed about half an inch below the surface of the w*ater; adher- 
ing air-bubbles must be carefully removed ; the body must be quite 
insoluble in water. 
(For a Table of the specific gravities of a large number of fatty 
and resinoid substances see the Pharmaceutical Journal for Oct. 11, 
1879.) 
Specific Gravity of Solids in Powder or Small 
Fragments. 
Weigh the particles; place them in a counterpoised specific- 
gravity bottle of known capacity, and fill up with water, taking 
care that the substance is thoroughly wetted; again weigh. 
From the combined weights of water and substance subtract 
the amount due to the substance; the residue is the weight of 546 
QUANTITATIVE ANA LYSIS. 
the water. Subtract this weight of water from the quantity 
which the bottle normally contains; the residue is the amount 
of water displaced by the substance. Having thus obtained 
the weights of equal bulks of water and substance, a rule-of- 
three sum shows the relation of the weight of the substance to 
1 part of water—the specific gravity. 
Or suspend a cup, short glass tube, or bucket from a short- 
ened balance-pan ; immerse in water; counterpoise; place the 
weighed powder in the cup, and proceed as directed for taking 
the specific gravity of a solid in mass. 
This operation may be conducted on fragments of any of the sub- 
stances the specific gravities of which are given in the foregoing 
Table, or on a powdered piece of marble the specific gravity of 
which has been taken in mass. The specific gravity of one piece of 
glass, first in mass, then in powder, may be ascertained; the result 
should be identical. The specific gravity of shot is about 11.350; 
sand, 2.600; mercury, 13.56. 
Specific Gravity of Solids Soluble in Water. 
Weigh a piece of sugar or other substance soluble in water; 
suspend it from a balance in the usual manner, and weigh it in 
turpentine, benzol, or petroleum, the specific gravity of which 
is known or has been previously determined ; the loss in weight 
is the weight of an equal bulk of the turpentine. Ascertain 
the weight of an equal bulk of water by calculation :— 
Sp. gr. of _ sp. gr. of _ , observed _ equal bulk 
turpentine ' water ' ' bulk of turp. ' of water. 
The exact weights of equal bulks of sugar and water being 
obtained, the weight of a bulk of sugar corresponding to 1.000 
of water is shown by a rule-of-three sum ; in other words, 
divide the weight of sugar by that of the equal bulk of water ; 
the quotient is the specific gravity of sugar. The stated specific 
gravity of the sugar ranges from 1.590 to 1.607. 
Specific Gravity of Solids Lighter than Water. 
This is obtained in a manner similar to that for solids 
heavier than water; but the light body is sunk by help of a 
piece of heavy metal, the bulk of water which the latter dis- 
places being deducted from the bulk displaced by both ; the 
remainder is the weight of a bulk of water equal to the bulk 
of the light body. For instance, a piece of wood weighing 12 
grammes (or grains) is tied to a piece of metal weighing 22 
grammes, the loss of weight of the metal in water having been SPECIFIC GRAVITY. 
547 
previously found to be 3 grammes. The two, weighing 34 
grammes, are now immersed, and the loss in weight found to 
be 26 grammes. But of this loss 3 grammes have been proved 
to be due to the buoyant action of the water on the lead; the 
remaining 23 therefore represent the same effect on the wood; 
23 and 12 therefore represent the weights of equal bulks of 
water and wood. As 23 are to 12, so is 1 to .5217. Or, 
shortly, as before, divide the weight in air by the weight of an 
equal bulk of water; .5217 is the specific gravity of the wood. 
Another specimen of wood may be found to be three-fourths 
(.750) the weight of water, and others heavier. Cork varies 
from .100 to .300. 
Specific Gravity of Gases. 
This operation is similar to that for liquids. A globe exhausted 
of air and holding from l to 4 litres (or quarts) is suspended from 
the arm of a balance, and counterpoised by a similar flask. Gases 
are introduced in succession and their weights noted. A rule-of- 
three sum shows their specific gravity in relation to air or hydrogen, 
whichever be taken as a standard. 
Correction of the Volume of Gases for Pressure.—The height of 
the barometer at the time of manipulation is noted. Remembering 
the fact that u the bulk of a gas is inversely as the pressure to which 
it is subjected” (Boyle and Mariotte), a simple calculation shows 
the volume which the gas would occupy at 760 millimetres (or 
29.922 inches), the standard pressure (30 inches is sometimes adopted 
as the standard in England*). Thus, 40 volumes of a gas at 740 
millimetres pressure are reduced to 39 when the pressure becomes 
760 millimetres (or 90 vols. at 29 ins. barom. become 87 vols. at 30 
inches.) 
Correction of the Volume of Gases for Temperature.—This is done 
in order to ascertain what volume the gas would occupy at 0° C. (32° 
F.), or 15° C. (59° F.), or 15°.5 C. (60° F.), according to the standard 
taken. Gases are equally affected by equal variations in tempera- 
ture (Charles). They expand about 0.3665f per cent, of their 
volume at the freezing-point of tcater for every C. degree (0.2036), or 
* In France the conventional standard height of the barometer is 
760 millimetres at 0° C. (32° F.); in England it is 30 inches, the 
temperature of the mercurial column being 60° F. 760 millims. is 
equivalent to 29.922 inches, hut the expansion of the metal between 
32° F. and 60° F. increases the length of the column to 30.005 inches. 
The standards are therefore almost identical, difference in true length 
being counterbalanced by the temperature at which the length is ob- 
served. 
f Corrected for the difference between the mercurial and air thermo- 
meters, the coefficient of expansion of air is 0.003656 (Miller). The 
coefficient of expansion of different gases varies very slightly, being 
somewhat higher for the more liquefiable gases. 548 
QUANTITATIVE AX A LYSIS. 
f°r every F. degree (Regnault). Thus, 8 volumes of gas at 0° 
(J. will become 8.293 at 10° C. ; for if 100 become 103.665 on being 
increased in temperature 10° C., 8 will become 8.293 (or if 100 be- 
come 102.036 on being increased 10° F., 8 will become 8.1629). 
Vapor-Density.—Vapors are those gases which condense to liquids 
at common temperatures. By the density of a vapor is meant its 
specific gravity. The density of a vapor is the ratio of any given 
volume to a similar volume of air or hydrogen at the same tempera- 
ture and pressure. But for convenience of comparison this experi- 
mental specific gravity is referred, by calculation as just described 
for permanent gases, to a temperature of 0° C. and 760 millimetres 
barom. A teaspoonful or so of liquid is placed in a weighed flask 
of about the capacity of a common tumbler and having a capillary 
neck ; the flask is heated in an oil-bath to a temperature considerably 
above the boiling-point of the liquid; at the moment vapor ceases 
to escape the neck is sealed by a blowpipe-flame and the tempera- 
ture of the bath noted; the flask is then removed, cooled, cleaned, 
and weighed ; the height of the barometer is also taken. The neck 
of the flask is next broken off' beneath the surface of water or mer- 
cury (which rushes in and fills it), and again weighed, by which its 
capacity in cub. centims. is found. From these data the volume of 
vapor yielded by a given weight of liquid is ascertained by a few 
obvious calculations. The capacity of the globe having been ascer- 
tained, the weight of an equal bulk of air* is obtained by a rule-of- 
three sum. This weight of air is deducted from the original weight 
of the flask, which gives the true weight of the glass. The weight 
of the glass is next subtracted from the weight of the flask and con- 
tained vapor (now condensed), which gives the weight of material 
used in the experiment. The volume which this weight of material 
occupied at the time of experiment is next corrected for temperature 
(to 0° C.) and pressure (760 millimetres) in the manner just described. 
The weight of a similar volume of hydrogen is next found.f The 
weights of equal volumes of hydrogen and vapor being thus deter- 
mined, the amount of vapor corresponding to one of hydrogen (the 
specific gravity or vapor-density) is shown by a short calculation. 
This process of finding the weight of a given volume of vapor is by 
Dumas. Gay-Lussac’s consists in determining the volume of a given 
weight; it has been improved by Hofmann. An excellent method 
by V. and C. Meyer consists, like that of Gay-Lussac, in determin- 
*1 cub. centim. of air at 0° C. and 7G0 niillims. weighs 0.001293 
gramme. 
f 1 litre (1000 cub. centims.) of hydrogen at 0° C. and 760 milli- 
metres (the barometer being at 0° C.) weighs 0.0896 gramme—a quan- 
tity sometimes termed a crith (from Kf>/0r/: krithe, a barley-corn—figu- 
ratively, a small weight); thus a litre of oxygen weighs 16 criths, 
chlorine 35.5 criths, etc. 100 cubic inches of hydrogen at 32° F. weigh 
2.265 grains; at 60° F., 2.143 grains (the barometer being 30 ins. at 
60° F. in both cases). 100 cubic inches of air at 32° F. weigh 32.698 
grains; at 60° F.. 30.935 (barom. 30 ins. at 60° F.). 1 cubic inch of 
water weighs 252.5 (252 458 at 62° F. and 30 ins. bar.) grains. 1 gallon 
of water contains 277|- (277.274 at 62° F.) cubic inches. SPECIFIC GRAVITY. 
ing the volume of the vapor of a given weight of a fluid or solid, but 
differs in the volume of the vapor being ascertained from an equal 
volume of air which the vapor is made to displace. (For a detailed 
description of this method and a drawing of the apparatus see Phar- 
maceutical Journal, May 17, 1879.) 
Experiment shows that the specific gravities of many gases and 
vapors on the hydrogen scale, and the proportions in which they 
combine by weight, are identical. Thus, chlorine is 35.5 times as 
heavy as hydrogen, and 35.5 parts unite with 1 of hydrogen to form 
hydrochloric acid gas. Hence, if the specific gravity of a gas or 
vapor is known, its combining proportion may be predicated with 
reasonable certainty, and vice versa. In applying this rule to gas- 
eous or vaporous compounds attention must be paid to the extent to 
which their constituent gases contract at the moment of combination 
or expand at the moment of decomposition. Thus, steam is found to 
be composed of two volumes of hydrogen and one of oxygen, the 
three volumes of constituents condensing to two at the moment of 
combination. Hence, steam may be expected to be nine times as 
heavy as hydrogen ; which experiment confirms. 
These relations may be so expressed as to include both element- 
ary and compound gases and vapors; thus, molecular weights and 
specific weights are identical. Molecular weights represent two 
volumes of a gas; specific gravity conventionally represents the 
relative weight of a gas compared with 1 volume of hydrogen or 
air; hence the specific gravity of a gas or vapor on the II scale is 
found by calculation on simply dividing the molecular weight by 2; 
on the air-scale, by dividing the hydrogen numbers by 14.44. For 
example, 
Specific Gravity. 
7C 
Molecular 
Molecular 
Aame. 
formula. 
weight. 
11 = 2. 
11 = 1. Air = 1. 
Hydrogen . . . 
. h2 
2 
2 
1 
.069 
Chlorine . . 
. C12 
71 
71 
35.5 
2.460 
Oxygen . . . 
. 0, 
32 
32 
16 
1.108 
Nitrogen . . . 
. N2 
28 
28 
14 
.970 
Steam .... 
. 11,0 
18 
18 
9 
.625 
Ammonia "as 
• nh3 
17 
17 
8.5 
.589 
Carbonic acid gas 
. CO, 
44 
44 
22 
1.524 
Alcohol (vapor) 
. c2h6o 
46 
46 
23 
1.593 
Air 
28.88 
14.44 
1.000 
These specific gravities closely correspond with those obtained by 
actual experiment. The specific gravity of any gas or vapor may 
therefore be calculated if the following data are at hand: (a) form- 
ula, (b) atomic weight of constituent elements; these give the mo- 
lecular weight, and the molecular weight divided by 2 is the specific 
gravity on the hydrogen-scale. Specific gravity on the air-scale is 
then deducible, if (c) the specific gravity of air (14.44) in relation 
to hydrogen be remembered. The absolute weight of any volume 
of a gas or vapor on the metric system is then obtainable if (d) the 
weight of a litre of hydrogen (0.0896 gramme) be known, or on the 
English plan by remembering (e) that 100 cubic inches of hydrogen 550 
QUA NTITATIVE ANALYSIS. 
at 60° F. weigh 2.143 grains (100 cubic inches of air at 60° F. weigh 
30.935 grains). 
In confirmation of these statements regarding the mutual relation 
of specific gravity and atomic weight a remarkable fact may be men- 
tioned. Regnault several years ago found the weights of 1 litre of hy- 
drogen and oxygen to be respectively .089578 and 1.429802 grammes. 
The latter number divided by the former gives 15.96 as the specific 
gravity of oxygen. Stas, in recent experimental researches on com- 
bining proportions, finds the atomic weight of oxygen to be not 16, 
but 15.96. 
Exceptions to the law occur in a few compounds and in arsen- 
icum and phosphorus, whose vapor-densities are twice that indicated 
by the rule. Possibly, in these cases the temperature employed is 
insufficient to dissociate an unusually complex molecule into mole- 
cules of usual complexity. As regards compounds, and, possibly, 
as regards those elements in which the observed density is only half 
that indicated by the rule, heat may, and in some cases probably 
does, produce molecular dissociation (thermolysis) into free atoms 
(uniatomic molecules) or into less complex molecules. 
Relation of the Specific Heat of Elements to their Atomic Weights. 
—Reference may here appropriately be made to a physical fact of 
great importance as regards molecular and atomic weights. In the 
earlier pages of this manual it was stated that elements do not com- 
bine chemically in haphazard proportions, but in fixed weights ; and 
abundant evidence of the truth of the statement has already been 
afforded, and will also be found in this section on Quantitative An- 
alysis. Secondly, it has been shown that elements do not combine 
in haphazard proportions by volume, but in certain constant bulks; 
and the weights of these bulks have been found to be identical with 
the combining weights themselves. Thirdly (this is the point to 
which attention is now drawn), if equal amounts of heat be given 
to elements in the solid state (that is, to solid elements or to solid 
compounds of volatile elements), and the quantity of the element be 
increased or diminished until each is thus heated through an equal 
number of degrees, it will be found that the different weights of ele- 
ments required are (in relation to a common standard) identical with 
the combining weights of the elements and with the weights of the 
combining volume of the elements. Thus, where 108 parts of silver 
would be employed, 207 of lead xvould be necessary.* Hence, in the 
determination of (a) combining proportion, {{>) specific gravity in 
gaseous state, and (c) specific heat, three distinct methods of ascer- 
taining atomic weight are available. In cases where one method is 
* Obviously, if equal weights of silver and lead were heated through 
an equal number of degrees, the silver would absorb nearly twice as 
much heat as the lead. In fact, as regards all the solid elements, “spe- 
cific heats and atomic weights are inversely proportional.” This law 
was discovered by Dulong and Petit. It follows that the product of 
the multiplication of the figures representing the specific heat of an 
element with the figures repi'esenting its atomic weight is, in the case 
of ever}' such element, the same number. SPECIFIC GRAVITY. 
551 
inapplicable, recourse is had to cither, or, if practicable, both, of the 
others, and thus the trustworthiness of observations and generaliza- 
tions placed more or less beyond question. The specific heat of a 
solid element is the same in the free as in the combined condition; 
therefore the specific heat of a molecule is the sum of the specific 
heat of its constituent atoms. From the specific heat of a solid 
compound of a volatile element (chlorine, for example) can thus be 
calculated the specific heat of an element in the solid state, even 
though the free element cannot itself be solidified. For the pro- 
cesses by which experimentally to determine specific heat the reader 
is referred to books on Physics. 
There is equivalency, also, between electrical and chemical action. 
The amount of electricity which would set free 127 parts of iodine 
would set free 80 parts of bromine. 
QUESTIONS AND EXERCISES. 
971. Define specific weight, or, as it is commonly termed, specific 
gravity. 
972. In speaking of light and heavy bodies especially, what stand- 
ard of comparison is conventionally employed? 
973. How are specific gravities expressed in figures? 
974. Why should specific gravities be taken at one constant tem- 
perature ? 
975. How does the buoyancy of air affect the real weight of any 
material ? 
976. Describe the difference between density and specific gravity. 
977. Give a direct method for the determination of the specific 
gravity of liquids. 
978. A certain bottle holds 150 parts, by weight, of water or 
135.7 of spirit of wine; what is the specific gravity of the latter? 
Ans. 0.9046. 
978a. An imperial fluidounce of a liquid weighs 366£ grains; 
what is its specific gravity? Ans. .838. 
979. Equal volumes of benzol and glycerin weigh 34 and 49 parts 
respectively, and the sp. gr. of the benzol is 0.850; what is the spe- 
cific gravity of the glycerin? Ans. 1.225. 
980. Explain the process employed in taking the specific gravity 
of solid substances in mass and in powder. 
981. State the method by which the specific gravity of a light 
body, such as cork, is obtained. 
982. What modifications of the usual method are necessary in 
ascertaining the specific gravity of substances soluble in water? 
983. How is the specific gravity of gases determined? 
984. By what law can the volume of a gas at any required pres- 
sure be deduced from its observed volume at another pressure ? 
985. To what extent will 78 volumes of a gas at 22.3 inches 
barometer alter in bulk when the pressure, as indicated by the 
barometer, is 30.2 inches? 552 
QUANTITATIVE ANALYSIS. 
986. Write a short account of the means by which the volumes 
of gases are corrected for temperature. 
987. At the temperature of 15° C. 40 volumes (litres, pints, 
ounces, cubic feet, or other quantity) of a gas are measured. To 
what extent will this amount of gas contract on being cooled to the 
freezing-point of water (0° C.)? 
Answer. As 1 vol. of any gas at zero expands or contracts .003605 
of a vol. for each rise or fall of 1° C., 1 vol. at 0° C., if heated to 15° 
C., will become increased by .054975 (that is .003665 multiplied by 
15); 1 vol. will expand to 1.054975. Conversely, 1.054975 vol. wi 11 
contract to 1 vol. if cooled from 15° C. to 0° C. And if 1.054975 
becomes 1 in cooling through 15° C., 40 vols. will (as found by rule 
of three) contract to 37.916. 
The following five problems and solutions are from Williamson’s 
Chemistry:— 
988. 10 litres of oxygen are measured off at 14° F. Required 
the volume of the gas at 15° C. 
Answer. The first operation must be to reduce the temperature 
quoted in Fahrenheit’s degrees to an equivalent value on the Centi- 
grade scale. 14° F. is 18° below 32° F., the freezing-point of water, 
and a range of 9° on the Fahrenheit scale is equal to a range of 5° 
on the Centigrade scale, so that the temperature at which the oxygen 
is measured off is —10° C. The rise of temperature up to 0° ex- 
pands the gas in such proportion that its volume at 0° is to its vol- 
ume at —10 as 1 is to 1 — 0.03665 •, i. e. as 1 to 0.96335. The further 
rise of temperature from 0° C. to 15° expands the gas in the propor- 
tion of 1 to 1 + 15 X 0.003665; i. e. 1 to 1.054975. The total rise 
of temperature therefore expands the gas in the proportion of 
of 0.96335 to 1.054975. 
0.96335 : 1.054975 : : 10 : 
. 10Xi«M?76 5_ 
0.96335 
989. 230 cubic centimetres of oxygen are measured off at 14° C. 
and 740 millimetres mercurial pressure. Required the volume of 
the gas at the normal temperature and pressure (0° C. and 760 
millimetres). 
Answer. Let the reduction for change of temperature be made 
first. The proportion 
1 + (14 X 0.003665) : 1 : : 230 : x 
gives 
x — —— — 218.774. 
1.05131 
To reduce this volume of 740 millimetres pressure to the volume 
corresponding to the pressure of 760 millimetres, we have the 
proportion 
38 : 37 : : 218.77 : z; 
whence 
*=3_7X21M1=213.02. 
38 SPECIFIC GRAVITY. 
990. A litre of oxygen is confined in a glass flask at 10° C. by the 
atmospheric pressure, added to that of a column of mercury 60 milli- 
metres high. The flask must be heated to 300° C. without any in- 
crease of volume taking place in the oxygen. How high must the 
column of mercury then be which presses on the gas, supposing the 
atmospheric pressure to remain constant at 760 millimetres? 
Answer. The oxygen is given at 10° C. and 820 millimetres pres- 
sure. If the pressure remained constant, the rise of temperature 
from 10° C. to 300° C. would expand the gas in such proportion 
that 1.03665 volumes would expand to 2.0995 volumes. In order to 
prevent any expansion the pressure must be increased in the same 
proportion, whence 
1.03665 : 2.0995 : : 820 x; 
820X2.0995 1RfinR 
1.03665 
From this total pressure the atmospheric pressure of 760 millimetres 
has to be deducted, leaving 900.6 millimetres as the height of the 
required mercurial column. 
991. A litre of oxygen is required of the density of 100 at 0° C. 
What weight of potassic chlorate must be used for its preparation, 
and what total pressure must be applied to it? 
Answer. The pressure required to compress oxygen from the den- 
sity of 16 to that of 100 is found by the proportion 
16 : 100 : : 760 : x ; 
76000 
. . x = = 4/ oO. 
16 
At the pressure of 4750 millimetres of mercury the weight of a litre 
of oxygen (16 grammes measure 11.2 litres at 0° C. and 760 millims. 
pressure) is found by the proportion 
760 : 4750 : : JA- : x: 
11.2 ’ 
whence 
„ 16 X 4750 q no 
x = = 8.93 grammes. 
11.2X760 
The weight of chlorate required for the evolution of 8.93 grammes 
of oxygen is found from the proportion 
48 : 122.5 : : 8.93 : x; 
.'. x — 22.8 grammes. 
992. What is the volume of 12 grammes of hydrogen at 15° C? 
Ansicer. One gramme of hydrogen measures 11.2 litres at 0° C.; 
therefore 12 grammes measure 12X11-2 = 134.4 litres at 0°. To 
find their volume at 15° C. we have the proportion 
1:1 + 15X0.003665 : : 134.4 : x; 554 
QUANTITATIVE ANALYSIS. 
whence 
x — 134.4 X 1.054975 = 141.788 litres. 
993. What interest for chemists have the specific heats of sub- 
stances ? 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
Preliminary Note.—Great care should he observed in selecting a 
fair sample of any hulk of material that is to be examined either by 
volumetric or gravimetric quantitative analysis. If the whole quan- 
tity is in separate parcels, and there is any ground for believing that 
the parcels differ in quality, they should, if practicable, he carefully 
mixed, or, technically, “ hulked.” Small portions should be taken 
from different parts of the resulting heap and well mixed in a mortar 
or other vessel, or in certain cases dissolved and the solution well 
stirred or shaken. A specimen of the powder or a portion of the 
solution may then he selected for analysis. 
Introduction.—The operations of volumetric analysis consist (u) 
in carrying out some definite chemical reaction, already well known 
to the operator, with (h) definite quantities of chemicals or salts; (c) 
the exact termination of the reaction between the two salts or chem- 
icals being ascertained—usually by some chemical indicator (litmus, 
starch, etc.). A portion of the chemical or salt, etc. to he tested is 
carefully weighed. To this is gradually added the second chemical 
or salt contained in the testing-fluid, commonly termed the Stand- 
ard Volumetric Solution. The usefulness and, indeed, the prepara- 
tion, of this Standard Solution is founded (as already indicated on 
page 521) on some accurate initial gravimetric operation. A weighed 
amount of a pure salt is dissolved in a given volume of water. “Ac- 
curately measured quantities of such a Standard Volumetric Solu- 
tion will obviously contain just as definite amounts of the dissolved 
salt as if those amounts were actually weighed in a balance, and, as 
measuring occupies less time than weighing, the volumetric opera- 
tions can be conducted with great economy of time as compared with 
the corresponding gravimetric operations.” 
APPARATUS. 
The only special vessels necessary in volumetric quantitative oper- 
ations are—1. A litre flask (Fig. 72), which, when filled to a mark 
on the neck, contains at 15° C., or about 60° F., one litre (1000 
cubic centimetres—i. e. 1000 grammes of water*); it serves for pre- 
paring solutions in quantities of one litre. 2. A tall cylindrical 
graduated litre jar (Fig. 71) divided into 100 equal parts ; it serves 
for the measurement and admixture of decimal or centesimal parts 
* A cubic centimetre is, strictlv speaking, the volume occupied bv 
one gramme of distilled water at its point of greatest density—namely, 
4° C.; metrical measurements, however, are uniformly taken at 15°.55 
C. (60° F.). VOLUMETRIC QUANTITATIVE ANALYSIS. 
555 
of a litre. 3. A graduated tube or burette (Fig. 73), which, when 
filled to 0, holds 100 cubic centimetres (a decilitre), and is divided 
into 100 equal parts; it is used for accurately measuring small vol- 
umes of liquids. 
Fig. 71. 
Fig. 72. 
Fig. 73. 
A litre jar. 
A litre flask. 
A burette, etc. 
The best form of burette is Mohrs. It consists of a "lass tube, 
commonly about the width of a little finger and the length of an 
arm from the elbow, contracted at the lower extremity and gradu- 
ated. The width and length of burettes, however, as well as the 
extent and fineness of their graduation, vary considerably. To the 
contracted portion is fitted a small piece of vulcanized caoutchouc 
tubing, into the other end of which a small spout made of narrow 
glass tube is tightly inserted. A strong wire clamp effectually pre- 
vents any liquid from passing out of the burette unless the knobs 
of the clamp are pressed by the finger and thumb of the operator, 
when a stream or drops flow at will. In place of the India-rubber 
tubing and clamp a stopcock is sometimes employed, and other 
modes of arresting the flow of liquid may be adopted. The accu- 
rate reading of the height of a solution in the burette is a matter 
of great importance; it should be taken from the bottom of the 
curved surface of the liquid. It may be still more exactly meas- 
ured by the employment of a hollow glass float or bulb (Erdmann’s 
float; see Fig. 73), of such a width that it can move freely in the 
tube without undue friction, and so adjusted in weight that it shall 
sink to more than half its length in any ordinary liquid. A fine 
line is scratched round the centre of the float; this line must 
always be regarded as marking the height of the fluid in the 
burette. In charging the burette a solution is poured in, not 
until its surface is coincident with 0, but until the mark on the 
float is coincident with 0. 556 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
ESTIMATION OE ALKALIES, ETC. 
Volumetric Solution of Oxalic Acid. 
On account of the bivalent character of the oxalic radical, and the 
univalent character of most of the metals contained in the salts 
which are estimated by oxalic acid, it is convenient that each litre 
of the volumetric solution should contain half a molecular weight 
in grammes of the acid (H2C204,21I20 = 126 2 = 63). 
If pure crystallized oxalic acid be at hand, the solution is made 
by dissolving 63 grammes in water, and making the volume up with 
more water to exactly one litre. 
Pure oxalic acid, however, not being easy to obtain, the solution 
may be made from the commercial acid by dissolving 65 to 70 
grammes in enough water to make a litre of solution, and then de- 
termining the strength of this solution by a titration with pure car- 
bonate of sodium, making use of the following memoranda:— 
(Crystallized Oxalic Acid, II2C204,2ir20 = 126.) 
Na2C03 + II2C204,2H20 = Na2C204 + C02 + 3II20 
2)106 
53 
2)126 
63 
Pure anhydrous carbonate of sodium is easy to obtain, for com- 
mercial bicarbonate is usually of such purity that when a few 
grammes are heated to redness for a quarter of an hour the result- 
ing carbonate is practically free from impurity. The bicarbonate 
should, however, be tested, and if more than traces of chlorides 
and sulphates are present, these may be removed by washing a few 
hundred grammes, first with a saturated solution of bicarbonate of 
sodium, and afterward with pure distilled water. After drying, the 
salt is ready for ignition. 
About half a gramme of the carbonate of sodium is accurately 
weighed and placed in a half-pint flask, around the neck of which is 
tied calico or leather to protect the fingers when the heated vessel is 
shaken bv the operator. The salt is dissolved in water to about 
one-third the capacity of the flask, and a few drops of the indicator, 
blue tincture of litmus, is added. The acid solution to be “set” or 
“ standardized ” is then poured into a burette, and run therefrom into 
the flask until the reddened litmus indicates the presence of free 
acid. This will be due in the first place to carbonic acid liberated 
and remaining dissolved in the solution. The contents of the flask 
are therefore boiled for several minutes, when the blue color will 
have returned. More acid is then run in until the mixture, after 
boiling, remains of a neutral color, indicating that just enough acid 
has been added to complete the reaction expressed in the foregoing 
equation. 
Let it be supposed that 0.6 gramme of carbonate of sodium was 
taken, and that this required 11 c.c. of oxalic acid solution; how 
many c.c. of this solution would contain 63 grammes of oxalic acid 
crystals? or, what is equivalent in the reaction, how many c.c. would ESTIMATION OF ALKALIES, ETC. 
557 
be required to neutralize 53 grammes of carbonate of sodium ? As 
0.6 gramme Na2C03 is to 11 c.c. sol., so are 53 grammes Na2C03 
to x c.c. sol.; x = 972 c.c. 972 c.c. (nearly) are equivalent to 53 
grammes of carbonate of sodium, and contain 63 grammes of oxalic 
acid. 
This solution may either be used as it is, or may be diluted with 
water, every 972 c.c. to be diluted to 1000 c.c., so that 1000 c.c. shall 
contain 63 grammes of oxalic acid. 
The following official substances are tested by this solution accord- 
ing to the United States Pharmacopoeia:— 
Solutions of Ammonia.—2 or 3 grammes of dilute, or about 1 
gramme of strong, solution of ammonia is a convenient quantity to 
operate upon. The weighing is most conveniently accomplished by 
taking a small stoppered bottle containing half an ounce or so of 
the substance, and, having ascertained its total weight, transfer 
about the quantity desired to the flask in which the estimation is 
to be conducted, and again weigh the bottle with what remains in 
it. The difference is the exact quantity taken. The weighing of 
the ammonia solution having been accomplished, water is added to 
about one-third the capacity of the flask (or, better, the ammonia is 
added to water already in the flask), and a few drops of tincture of 
litmus introduced. The titration is then conducted as described be- 
fore, except that no heat is employed. 
2NITJIO + H2C204,2H20 = (NH4)2C204 + 4H20 
2)70 
35 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
2NHjH20 + II2CA,2II20 = (NH4)./J204 + 4 If/) 
2)34 
17 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
1000 c.c. of standard solution, or its equivalent of a solution of 
any other strength, would, according to this reaction, neutralize 17 
grammes of ammonia gas (NII3) or 35 grammes of hydrate of am- 
monium (NTI,HO). If 3 grammes of ammonia solution had been 
taken, and it had required 15 c.c. of standard oxalic acid solution, 
then the amount of ammonia gas or hydrate of ammonium it con- 
tained would be seen by the following calculations:— 
1000 c.c. : 17XH., : : 15 c.c. : x = .255 grammes NIL, ■« 
1000 c.c. : 35NILJIO : : 15 c.c. : x — .525 grammes NII JIO 
Three grammes, then, would contain .255 grammes of the gas or 
.525 grammes of hydrate of ammonium. Or, in percentage, 
3 gr. sol.: .255 gr. NH3 :: lOOgr. sol.: xgr. NH3 — 8.5%NIL, 
3gr. sol.: .525 gr. NiIJiO :: 100 gr. sol.: xgr. NII JIO = 17.5%NII4IIO 
The solution would therefore contain 8.5 per cent, of ammonia gas 
(NH3) or 17.5 per cent, of hydrate of ammonium (NII4IIO). If the 
oxalic acid solution was not of full standard, the number of c.c. which VOLUMETRIC QUANTITATIVE ANALYSIS. 
contained 63 grammes of oxalic acid—which was, in fact, equivalent 
to 1000 c.c. of standard solution—would be substituted for 1000 c.c. 
in the preceding proportions. 
A comparison should now be made with the requirements of the 
Pharmacopoeia. It is useful to express results as percentage of sub- 
stance of pharmacopneial strength in the material examined. Thus 
the U. S. Pharmacopoeia requires dilute ammonia solution (both Aqua 
Ammonia; and Spiritus Ammonia?) to contain 10 per cent, of the gas 
(NH3). t he solution supposed to have been operated on contained 
8.5 per cent. NH3 (10 : 8.5 : : 100 : x = 85). Therefore it contains 85 
per cent, of the dilute ammonia of the U. S. Pharmacopoeia.* 
Strong Solution of Ammonia, U. S. P., contains 28 per cent, of 
ammonia gas (N1I3). 
Note.—The calculations just described for ammonia are similar to 
those employed throughout volumetric analysis ; they will not be re- 
peated, therefore, in the case of every substance. 
Carbonate of Ammonium.—The reactions indicated by the fol- 
lowing equations occur between commercial carbonate of ammonium 
and oxalic acid :— 
6)314 
52.33 
2N3HuCA + 3H,CsO„2HaO = 3(NII4)2C204 + 8IIa0 + 4C02 
6)378 
63 = grammes in 1000 c.c. of standard solution. 
About 1 gramme is a convenient quantity to operate upon. Tinc- 
ture of litmus is the indicator, and the titration is conducted at a 
temperature just short of boiling. The estimation is not very satis- 
factory, because the heat employed, while scarcely sufficient to expel 
the carbonic acid gas, is enough to occasion loss of ammoniacal salt. 
Practised analysts usually add excess of the standard acid, and thus 
* Extremely minute quantities of ammonia—1 part in many millions 
of water—may be estimated volumetrically by adding excess of a color- 
less solution of red iodide of mercury (Kessler’s test), then in a similar 
vessel, containing an equal amount of pure water with excess of the 
Kessler reagent, imitating the deptli of yellow or reddish-yellow color 
thus produced by adding an ammoniacal solution of known strength. The 
amount of ammonia thus added represents the amount in the original 
liquid. 
The Nessler Reagent.—A litre may be made by dissolving 30 or 40 
grammes of iodide of potassium in a small quantity of hot water, add- 
ing a strong hot solution of perehloride of mercury until the precip- 
itate of mercuric iodide ceases to redissolve even by the aid of rapid 
stirring and heat, slightly diluting, filtering, adding a strong solu- 
tion of (120 to 140 grammes) caustic soda or (160 to 180 grammes) 
caustic potash, and diluting to 1 litre. A few c.c. (5 or 6 or more) of a 
strong solution of perehloride of mercury are finally stirred in, the 
whole set aside till all precipitated red iodide has deposited, and the 
clear liquid decanted for use. The reaction of this Kessler test with 
ammonia is as follows:— 
KII3 + 2HgI2 + 3KIIO NHgjI + SKI + 3H20. ESTIMATION OF ALKALIES, ETC. 
fix every trace of ammonia; then gently boil to get rid of carbonic 
acid gas ; bring back the liquid to neutrality by an observed volume 
of standard alkaline solution, and deduct an equivalent volume of 
acid from the quantity first added. The United States Pharmaco- 
poeia requires 5.232 grammes to neutralize 100 c.c. of standard solu- 
tion of oxalic acid. This corresponds to 100 per cent, of carbonate 
having the formula N3HuC205. 
Borax.—Two or three grammes is a convenient quantity. 
Na2B4O7,10H2O + II2C204,2H20 = Na2C204 + H2B407 + 12II20 
2)382 
191 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
Tincture of litmus is the indicator, and the titration may be carried 
on without heat. The liberation of boracic acid colors the litmus 
wine-red. This is not regarded, the titration being continued until 
the bright red due to the action of free oxalic acid makes its appear- 
ance. Both the British and United States Pharmacopoeias require 
borax to be pure (= 100 per cent.). 
Lead Acetate and Solution of Subacetate.—Operate upon about 
three grammes of acetate of lead and from live to ten grammes of 
solution of subacetate. 
Pb2C2H302,3H20 + H2C204,2H20 = PbC204 + 2HC2H302 -f 5H20 
2)378.5 
189.25 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
Pb202C2TI302 + 2(H2C204,2II20) = 2PbC204 + 2HC2H302 + 5H20 
4)54-7 
136.75 
4)252_ 
63 = grammes in 100C c.c. of standard solution. 
The flask in which the estimation is being conducted should contain 
one third of a flaskful of water. In the case of both acetate and 
solution of subacetate of lead a little acetic acid should be added to 
prevent precipitation of basic salt on dilution. The only indicator 
of complete reaction is cessation of production of the precipitate— 
oxalate of lead. The United States Pharmacopoeia requires acetate 
of lead to be pure (100 per cent.), and solution of subacetate to con- 
tain 25 per cent. 
Lime- Water and Saccharated Solution of Lime.—Measure about 
half a litre of lime-water for the estimation, and of saccharated 
solution weigh about 25 grammes. The following equations, etc. 
are quantitative expressions of the reactions:— 
Ca2II0 -4- II,C204 = CaC204 + 211,0 
2)74 
37 
21126 
63 = grammes in 1000 c.c. of standard solution. 560 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
Or, 
Ca0,II20 + H2C204 = CaC204 + 2II20 
Litmus is used as an indicator. 
Caustic Potash and Soda, Potassium and Sodium Carbonates and 
Bicarbonates.—Litmus is the indicator throughout, and heat is used 
in all cases, for the caustic alkalies always contain some carbonate. 
2)56 
28 
2)126 
63 = grammes in 1000 c.c. of standard solution 
2KII0 + II2C204,21I20 == K2C204 + 4II20 
2)112 
56 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
2NalI0 + HsC204,2II20 = Na2C204 + 4H20 
2)80 
40 
2)126 
63 — grammes in 1000 c.c. of standard solution. 
K2C03 + II2C204,2H20 = K2C204 + C02 + 3H20 
2)138 
69 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
Or, 
K2C03 + 16%H20 + H2C204,2H20 = K2C204 + C02 + xll20 
2)164.28 
82.14 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
Na2C03 + II2C204,2H20 = Na2C204 + C02 + 3H20 
2)106 
53 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
Or, 
Na.CO3,10H2O + H2C204,2H20 = Na2C204 + C02 + 13H.0 
2)286 
143 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
2KIIC03 + II2C,04,2Hs0 = K2C204 + 2C02 + 4II20 
2)200 
100 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
2NaHC0# + H2C204,2H20 = Na.UA + 2C02 + 4H.0 
2)168 
84 
2)126 
63 = grammes in 1000 c.c. of standard solution. 
Convenient quantities to operate with are: Of caustic potash, 
1 gramme; caustic soda, .5 to 1 gramme; potassium carbonate or ESTIMATION OF ALKAEIES, ETC. 
561 
bicarbonate, 1 to 2 grammes; sodium carbonate or bicarbonate, 
2 to 3 grammes; dried sodium carbonate, .5 to 1 gramme; and of 
solutions a corresponding quantity. The United States Pharma- 
copoeial requirements are: Caustic potash or soda, 90 per cent, 
of KUO or NallO; potassium carbonate, 81 per cent, of K,COs; 
sodium carbonate, 98 per cent, of Na,C03,1011,0; potassium bicar- 
bonate, 100 per cent, of KHC03; sodium bicarbonate, 99 per cent, 
of NaHCO,; and commercial bicarbonate, at least 95 per cent. The 
dried carbonate (Sodii Carbonas Exsiccatus, U. S. P.) is to contain 
72.6 per cent, of real carbonate. Liquor Eotassce and Liquor Sodas 
must contain 5 per cent, of pure hydrate. 
The strength of soda-ash is often reported in terms of “soda’’— 
that is, oxide of sodium (Na,0 = 62). The old molecular weight 
of carbonate of sodium, 54 (it should have been 53), derived from 
that of “soda,” 32 (it should have been 31), is still employed in 
Great Britain in reporting the strength of soda-ash. The true 
amount of soda equivalent to 54 parts of carbonate is 31.41 parts. 
A modern analyst having found the true amount of soda in a sample 
of soda-ash is expected by some manufacturers to report 31 as 31.41 
parts, or 53 of carbonate as 54, and other quantities in proportion 
to these figures. 
Tartrates and Citrates of Potassium and Sodium and Acetate of 
Potassium.—When tartrates or citrates of alkali-metals are burned 
in the open air the whole of the metal remains in the form of 
carbonate. Each molecular weight of a neutral tartrate gives one 
molecular weight of carbonate, and every two molecular weights of 
an acid tartrate give one molecular weight of carbonate. Advantage 
is taken of these reactions to estimate indirectly the quantity of 
citrate or tartrate in presence of substances with which they are 
generally associated. One to two grammes of any of these salts is 
a convenient quantity to operate upon. The ignition may be con- 
ducted in a platinum or porcelain crucible. A low red heat only 
should be used, and the vessel removed when complete carbonization 
has been effected—that is to say, when nothing remains but the 
carbonate and free carbon. The mixture is in this case treated with 
hot water, and the carbon separated by filtration. If too little heat 
has been used and carbonization is not complete, the filtrate will be 
more or less colored. If this should be the case the operation must 
be repeated with a fresh quantity of material. The carbonate is 
titrated in the usual way. The following equations, etc. explain 
the reactions:— 
2K204II40«,II„0 + 502 = 2K2C03 + 6C02 + 411,0 
4)470 
117.5 
4)276 
69 = 1000 c.c. of standard oxalic acid solution. 
2KIIC4II,06 4- 50, = K,C03 + 7C0, + 511,0 
2)376 
188 
2)138 
69 = 1000 c.c. of standard oxalic acid solution. 562 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
2(K,C6H50T>n,0) + 902 = 3K.C0, + 9C02 + 7II20 
6)648 6)414 
108 69 = to 1000 c.c. of standard oxalic acid solution. 
2(KNaC4H406,4H,0) -f 50, = 2KNaC0s + 6C02 + 811,0 
4)564 4)244 
141 61 =1000 c.c. of standard oxalic acid sol. 
2KC2II.j02 + 402 = K2C03 + 3C02 + 3H20 
2)196 
98 
2)133 
69 = 1000 c.c. of standard oxalic acid solution. 
It will be readily understood that in the first (for example) of the 
reactions just expressed 113 weights of tartrate of potassium are 
equivalent to 69 weights of carbonate of potassium ; and as in a 
previous reaction it has been shown that 69 weights of carbonate of 
potassium are equivalent to 63 weights of oxalic acid, it follows that 
113 weights of tartrate of potassium are equivalent to 63 weights of 
oxalic acid. Let these weights be grammes, and then 113 grammes 
of tartrate of potassium are equivalent to 63 grammes of oxalic 
acid, or to 1000 c.c. of the standard solution of oxalic acid. If the 
substance estimated be a crude sample of tartrate of potassium, and 
the number of c.c. of oxalic acid used has been 15 c.c., then as 1000 
c.c. of the acid solution are to 113 grammes of tartrate of potassium, 
so are 15 c.c. of the solution to 1.695 grammes of tartrate of potas- 
sium. Now, if the weight of the sample taken was 2 grammes, 
then as 2 grammes of the sample contain 1.695 of real tartrate of 
potassium, 100 will contain x=-84.75 per cent, of real tartrate. 
These salts are required to be 100 per cent, pure by the United 
States Pharmacopoeia, except acetate of potassium, which is to have 
98 per cent, of real acetate. Trade samples are practically pure as 
a rule. 
Permanganate of Potassium.—The reaction is shown in the fol- 
lowing equation: K2Mn2Og -j- 3II2S04 -j- 5(II2C204,2II20) = K2S04- 
+ 2MnS04 + 18II20 + 10CO2. 
K2Mn208 and 5(II2C204,2II20) 
10)314 
31.4 
10)630 
63 = grammes in 1000 c.c. of standard solution. 
The salt satisfies official requirements if it contains 98.8 per cent, of 
real permanganate of potassium. 
Notes. 
Alkalimetry.—The foregoing processes are often spoken of as 
those of alkalimetry (the measurement of alkalies). 
Neutral solution of litmus is prepared by digesting the commercial ESTIMATION OF ACIDS. 
563 
fragments in about 15 or 20 times their weight of water for a few 
hours, decanting, dividing into two equal portions, adding acid to 
one till it is faintly red, then pouring in the other and mixing. The 
solution may be kept in a stoppered bottle and occasionally exposed 
to the air. It should never be filtered, but gradually allowed to 
deposit. 
Standard sulphuric acid may be used in the place of oxalic acid, 
1000 c.c. of the liquid containing half of the molecular wreight of 
the pure acid in grammes. It is prepared by diluting oil of vitriol 
with from 3 to 4 times its bulk of distilled water, ascertaining how 
much of the acid liquid is required to exactly neutralize of the 
molecular weight of pure carbonate of sodium, taken in grammes 
(5.3), and adding water until the observed volume of acid is in- 
creased to 100 c.c., the wdiole of the fluid being similarly diluted. 
Weighing.—In the case of substances which are liable to alter by 
exposure to air it is important that a selected quantity should be 
quickly weighed, rather than selected weights be accurately bal- 
anced by material, the former operation occupying much the shorter 
time. 
Salts other than the official may be quantitatively analyzed by the 
volumetric solutions of the Pharmacopoeia, slight modifications of 
manipulation even enabling the processes to be adapted to fresh 
classes of salts. Ample instructions for extending operations in 
this manner will be found in Sutton's Handbook of Volumetric 
Analysis. 
QUESTIONS AND EXERCISES. 
990. Describe the various pieces of apparatus used in volumetric 
determinations. 
991. One hundred cubic centimetres of solution of oxalic acid 
contain 6.3 grammes of the crystallized acid; work sums showing 
what weights of bicarbonate of potassium and anhydrous carbon- 
ate of sodium that volume will saturate. Ans. 10 grammes and 5.3 
grammes. 
992. Show what weight of hydrate of potassium is contained 
in solution of potash, 48.02 grammes of which are saturated 
by 50 c.c. of the standard solution of oxalic acid. Ans. 5.83 
per cent. 
993. Calculate the percentage of hydrate of calcium in lime- 
water, 438 grammes of which are neutralized by 20 c.c. of the 
volumetric solution of oxalic acid. Ans. 0.1689. 
994. Eight grammes of a sample of llochelle salt, after ignition, 
etc., require 54.3 c.c. of the official oxalic acid solution for complete 
saturation ; work sums showing w hat is the centesimal proportion 
of real salt present. Ans. 95.7. 
In the previous experiments a known amount of an acid has been 
used in determining unknown amounts of alkalies. In those about 
ESTIMATION OF ACIDS. 564 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
to be described a known amount of an alkali is employed in esti- 
mating unknown amounts of acids. The alkaline salt selected may 
be either a hydrate or a carbonate; but the former is to be pre- 
ferred, for the carbonic acid set free when a strong acid is added to 
a carbonate interferes to some extent with the indications of 
alkalinity, acidity, or neutrality afforded by litmus. The alkali 
most convenient for use is soda, a solution of which has probably 
already been made the subject of experiment in operations with the 
standard solution of oxalic acid. It should be kept in a stoppered 
bottle and exposed to air as little as possible. 
Volumetric Solution of Soda. 
(Hydrate of Sodium, NaTIO - 40.) 
This aqueous solution of soda is most conveniently made of such 
a strength that each 1000 c.c. contains one molecular weight in 
grammes of the alkali (NallO = 40). It will be seen from the fol- 
lowing equation that 40 grammes of soda convert 63 grammes of 
oxalic acid into neutral oxalate of sodium. Therefore, 1 litre of 
this solution, containing 40 grammes of soda, will form a neutral 
solution of oxalate with 1 litre of standard oxalic acid solution, 
or with a chemically equivalent quantity of oxalic acid solution of 
any other strength. 
II2C204,2II20 + 2NaH0 = Na2C204 + 4II20 
2)126 
63 = 1000 c.c. of stand, sol. 
2)80 
40 = 1000 c.c. of standard solution. 
If pure soda were at hand, it would only be necessary to weigh 
40 grammes, dissolve this in water, and dilute to 1 litre. But 
pure soda cannot readily be produced. Therefore weigh about 45 
grammes of hydrate of sodium of trade, and add water to 1 litre. 
When dissolved take, say, 14 c.c., dilute with more water in a ilask, 
add a few drops of tincture of litmus, and titrate with oxalic acid 
solution of known strength. Suppose that the volume of standard 
acid solution required to neutralize the 14 c.c. of soda solution the 
strength of which is to be estimated lias been 15 c.c., or an equiva- 
lent amount of acid solution of another strength; then, how many 
c.c. of soda solution is equivalent to 1000 c.c. of standard acid solu- 
tion ? or, what comes to the same thing, how many c.c. of soda solu- 
tion contain 40 grammes of real soda (NallO)? As 15 c.c. stand- 
ard acid are to 14 c.c. soda solution, so are 1000 c.c. standard acid 
to x c.c. x = 933 c.c. 933 c.c. of the soda solution contain, there- 
fore, 40 grammes of soda. This may either be diluted, every 933 
c.c. to 1000 c.c., so that it may be standard (10(X) c.c. ==40 grammes 
NallO), or the solution may be used without dilution (933 c.c. = 40 
grammes NallO). It has already been mentioned that soda nearly 
always contains carbonate. To remove resulting carbonic acid, 
therefore, gentle heat should be employed toward the close of each ESTIMATION OF ACIDS. 
565 
titration in all the estimations with this solution. Litmus is used 
throughout as an indicator of completion of the reaction. The 
following substances are officially estimated with this solution. 
The list admits of considerable extension (see Sutton's Volumetric 
Analysis). 
Acetic Acid.—Operate upon about 1 gramme of glacial acid, 
about 20 grammes of dilute acid, or about 3 grammes of ordinary 
acetic acid. 
IIC2II302 + NallO = NaC2II302 + II20 
60 
40 = 1000 c.c. standard solution. 
Acetic Acid, U. S. P., should contain 36 per cent of real acid 
(HC2II302); Dilute Acetic Acid, U. S. P., 6 per cent; Glacial 
Acetic Acid, U. S. P., 99 per cent. 
Citric Acid.—Operate on about 1 gramme. The reaction is ex- 
pressed by the following equation, etc.:— 
II3C6lI507,II,0 + 3 NallO = Na3C6H507 + 4II20 
3)210 
70 
3) 12ft 
40 = 1000 c.c. standard solution. 
Citric Acid, U. S. P., should be pure ( = 100 per cent. 
H3C-H507,H20). 
Hydrochloric Acid.—Operate on from 1 to 2 grammes of the con- 
centrated acid or on about 4 grammes of the dilute acid. 
HOI + NallO = • NaCI + 1I20 
36.4 
40 = 1000 c.c. standard solution. 
Hydrochloric Acid, U. S. P., should contain 31.9 per cent, of real acid 
(HC1), and Dilute Hydrochloric Acid, U. S. P., 10 per cent. 
Dilute Hydrobromic Acid.—Operate on from 8 to 12 c.c. 
IIBr + NallO = NaBr -f H20 
Dilute Hydrobromic Acid, U. S. P., should contain 10 per cent, of 
real acid (HBr). 
Lactic Acid.—Operate on 1.5 to 2 grammes. The reaction is ex- 
pressed by the following equation :— 
80.8 
40 = 1000 c.c. standard solution. 
HC3H503 + NallO = NaC3H303 + II20 
90 
40 —1000 c.c. of standard solution. 
Lactic Acid, U. S. P., should represent 75 per cent, of absolute lactic 
acid (HC3H503). 
Nitric Acid.—Operate on from 1 to 2 grammes of concentrated or 
on from 4 to 5 grammes of dilute acid. 566 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
HN03 + NaHO = NaN03 + II20 
63 
40 = grammes in 1000 c.c. standard solution. 
Nitric Acid, U. S. P., should contain 69.4 per cent., and Dilute Nitric 
Acid, U. S. P., 10 per cent., of real acid (1IN03). 
Sulphuric Acid.—Operate upon from .5 to 1 gramme of concen- 
trated acid or from 4 to 5 grammes of either Dilute or Aromatic Sul- 
phuric Acid. 
II2S04 + 2NaTI0 = Na2S04 + 2Ha0 
2)98 
49 
2)80 
40 = grammes in 1000 c.c. standard solution. 
Sulphuric Acid, U. S. P., should contain not less than 96 per cent., 
Dilute, U. S. P., 10 per cent, of real acid, and Aromatic, U. S. P., 
18 per cent., of sulphuric acid (II2S04), partly as ethyl-sulphuric 
acid. 
Tartaric Acid.—Operate upon about 1 gramme of the acid. The 
following equation, etc. represents the reaction :— 
II2C4II406 + 2NaII0 = Na2C4II406 + 2II20 
2)150 
75 
2)80 
40 = grammes in 1000 c.c. standard solution. 
Tartaric Acid, U. S. P., should contain 100 per cent, of II2C4II406. 
Notes.—1. Pure acetates, citrates, tartrates, and some other organic 
salts have an alkaline action on litmus, but not to an important ex- 
tent. If the soda solution be added to acetic, citric, or tartaric acid 
containing litmus until the liquid is fairly blue, the operator will 
obtain trustworthy results. In delicate experiments turmeric, “ me- 
thyl-orange,” “phenolphthalein,” etc. may be used instead of litmus. 
2. The operations for the quantitative analysis or measurement of 
acids are often collectively spoken of under the name of acidimetry. 
QUESTIONS AND EXERCISES. 
995. Calculate the percentage of real acid present in diluted sul- 
phuric acid, 30 grammes of which are neutralized by 84 c.c. of the 
official volumetric solution of soda. Ans. 13.72. 
996. Show how much real nitric acid is contained in a solution 36 
grammes of which are saturated by 94 c.c. of the standard solution 
of soda. Ans. 16.45 per cent. 
ESTIMATION OF ACIDULOUS RADICALS PRECIP- 
ITATED BY NITRATE OF SILVER. 
The purity of many salts and the strength of their solutions may 
be determined by this process. Diluted Hydrocyanic Acid, Bromide 567 
ESTIMATION OF ACIDULOUS RADICALS. 
Potassium, Bromide of Ammonium, Cyanide of Potassium, Bro- 
mide of Sodium, Syrup of Hydriodic Acid, Syrup of Bromide of 
Iron, and Syrup of Iodide of Iron are quantitatively analyzed by 
standard solution of nitrate of silver. 
Standard Solution of Nitrate of Silver. 
Dissolve 16.97 grammes of crystals of pure nitrate of silver 
in 1 litre of water. 1000 c.c. of this solution contain of 
the molecular weight in grammes of nitrate of silver. It is 
therefore a decinormal solution. 
Pure crystals of nitrate of silver can readily be obtained. When 
this is not the case, and pure chloride of sodium is at hand, a solu- 
tion may be made of approximate strength, and then be standardized 
by means of that salt. The method may be thus indicated:— 
(Nitrate of Silver, AgNOs — 169.7.) 
NaCl + AgNOj = AgCl + NaN03 
10)58.5 
5.85 
10)169.7 
16.97 = grammes in 1000 c.c. of standard solution. 
Take rather less than 1 gramme of the chloride of sodium (NaCl) 
and dissolve in water. The salt (AgCl) precipitated in the reaction 
is an insoluble salt, and the end of its precipitation will serve as a 
good indication of the completion of the reaction. A better in- 
dicator, however, is a few drops of neutral chromate of potassium 
(which should previously be purified by recrystallization). The 
nitrate of silver does not act upon the chromate until all the chlo- 
ride is converted into chloride of silver, after which a (lecp-rcd pre- 
cipitate of chromate of silver is produced. This indication is ex- 
tremely delicate, and in practice is noticed when the white color due 
to chloride of silver changes to yellowish from formation of the first 
traces of chromate of silver. The titration being accomplished, sup- 
pose that .1 gramme of the chloride of sodium has taken 17 c.c. of 
the nitrate of silver solution cf unknown strength : how many c.c. 
of the solution are equivalent to 5.85 of the chloride of sodium ? 
that is, how many c.c. of solution contain 16.97 grammes of nitrate 
of silver? As .1 gramme of NaCl is to 17 c.c., so are 5.85 NaCl 
to x c.c. = 994 c.c. 994 c.c. of the solution of nitrate of silver are 
equivalent, therefore, to 1000 c.c. of official standard solution, and 
contain 16.97 grammes of the nitrate of silver. They may be di- 
luted to 1000 c.c. if desired. 
Hydrocyanic Acid.—Three to four grammes of the dilute acid 
form a convenient quantity to operate upon. The TICN is first, 
converted into KCN or NaCN with potash or soda. rlhe following 
equations, etc. explain the reactions:— 
21ICN + 2NaIlO = 2NaCN + 2IIaO 
10)54 
5.4 
10)98 
9.8 568 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
2NaCN + AgN03 = AgCN,NaCN + NaNO, 
10)98 
9.8 
10)169.7^ 
16.97 = grammes in 1000 c.c. of standard solution. 
Tt is seen that 5.4 grammes of real hydrocyanic acid (HCy) are 
equivalent to 9.8 grammes of cyanide of sodium, and represent 
16.97 grammes of nitrate of silver, or 1000 c.c. of standard solution 
of nitrate of silver. 
The cyanide of sodium having been obtained, the titration is carried 
on until it is converted into the soluble douide salt (NaCy,AgCy), 
immediately after which a permanent turbidity occurs, due to pre- 
cipitation of cyanide of silver, thus:— 
AgCy,NaCy + AgNOs = 2AgCy + NaN03. 
This turbidity affords a delicate and satisfactory proof of the com- 
pletion of the above reaction, which is the B. P. process. 
There is, however, a difficulty in the conversion of the acid into 
the cyanide (Siebold) to which it is necessary to pay particular atten- 
tion. Tincture of litmus is added to the acid diluted largely with 
water, and the soda poured in. Owing to the strong alkaline reac- 
tion of the cyanide of sodium formed, the mixture becomes blue 
when only a small proportion of the acid has been converted. If 
then the titration be conducted until the turbidity appears, only the 
cyanide of sodium will be estimated, leaving free hydrocyanic acid 
still unacted upon. Indeed, cyanide of sodium may be estimated in 
presence of hydrocyanic acid in this way. Thus the following reac- 
tion (expressed approximately) might occur : 
NaCy + 4IICy + AgNOs = AgCy + NaN03 + 4IICy 
Alkaline. 
Turbid aud acid. 
In this case only one-fifth of the acid originally present would be 
estimated. The mixture would, however, become acid. If this 
acidity be prevented all difficulty is overcome. The following de- 
tails (Senior) will be found to answer well: To the diluted hydro- 
cyanic acid add soda solution to a strong alkaline reaction, deter- 
mined by means of tincture of litmus. Then add the silver solution, 
drop by drop, from the burette, when in most cases the mixture will 
become acid. When it does so, add more soda solution, and repeat 
this process until the final reading, when the solution must be alka- 
line. In this way the addition of too much soda at the commence- 
ment, which would use up silver solution and make the reading a 
trifle too high, is avoided. 
Dilute Hydrocyanic Acid, U. S. P., should contain 2 per cent, of 
real acid (HCN), as shown by the following process:— 
The following is the quantitative test of purity ordered by the 
United States Pharmacopoeia:—“13.5 gm. diluted with 30 c.c. of 
water, and mixed with enough of an aqueous suspension of mag- 
nesia to make the mixture quite opaque, and afterward with a few 
drops of solution of chromate of potassium, should require 50 c.c. of ESTIMATION OF ACIDULOUS RADICALS. 
569 
the volumetric solution of nitrate of silver before the red color 
caused by the latter ceases to disappear on stirring (corresponding 
to the presence of 2 per cent, of absolute Hydrocyanic Acid).” By 
this method the whole of the IlCy is precipitated as AgCy before the 
chromate of silver is permanently precipitated, and 13.5 grammes 
of dilute HCy, U. S. P., will therefore require 100 c.c. of volumet- 
ric nitrate of silver, not 50 c.c., as stated by the Pharmacopoeia. 
Bromide of Ammonium.—Operate upon .075 to .1 gramme of the 
salt, using chromate of potassium (or Bichromate, U. S. P.) as an 
indicator of the close of the reaction :— 
NH4Br + AgNOj = AgBr + NH4NOs. 
10)97.8 10)169.7 
9.78 16.97 = 1000c.c. of standard solution. 
Bromide of Ammonium, U. S. P., should be of 97 per cent, purity, 
but as the impurity is chloride of ammonium, this too will be pre- 
cipitated by the nitrate of silver, and must be calculated in finding 
the percentage of bromide. 
NH4C1 + AgN03 = AgCl + NH4N03. 
10)53,5 
5.35 
10)169.7 
16.97 = 1000c.c. of standard solution. 
The amount of the salt equivalent to 1000 c.c. of standard solution 
is first calculated by simple proportion : Let x represent this ; then 
9.78 — x — y, the excess of standard solution used up by the chloride 
of ammonium, reckoned in terms of bromide (NH4Br); and since 
5.35 grammes of NH4C1 = 9.78 grammes of NH4Br, the excess 
which ammonium chloride can consume is represented by 9.78 — 
5.35 = 4.43; 
therefore, as 4.43 : 5.35 : : # : z = the amount of chloride of am- 
monium present in x grammes of the sample taken; lastly, the per- 
centage is calculated by simple proportion: 
As x : 100 : : z : p = percentage. For example: .075 gramme 
of the salt required, 7.8 c.c. of standard solution, 
1. 7.8 : 1000 : : .075 : *; 
* = 9.615. 
2. 9.78 — 9.615=#; 
# = .165. 
3. 4.43 : 5.35 : : .165 : z; 
z = . 19926. 
4. 9.615 : 100 : : .19926 : p -, 
p = 2.072 per cent, of NH4C1. 
Bromide of Potassium.—Operate upon rather less than .1 
gramme, and conduct the titration in the same manner as with 
chloride of sodium, using chromate of potassium as an indicator 
of the close of the reaction :— 570 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
KBr -f- AgNOs — AgBr -f- KN03 
10)118.8 
11.88 
10)169.7 
16.97 = grammes in 1000 c.c. of standard solution. 
To calculate the KOI, proceed as for NH4C1, 74.5 of KC1 being 
equal to 118.8 of KBr. 
The United States Pharmacopoeia requires Bromide of Potassium 
to contain 97 per cent, of the salt. 
Bromide of Sodium.—Operate upon .1 gramme, and proceed 
exactly as for bromide of ammonium:— 
NaBr + AgNOs = AgBr + NaN03 
10)102.8 
10.28 
10)169.7 
16.97 = 1000 c.c. of standard solution. 
Bromide of Sodium, U. S. P., should be of 97 per cent, purity, and 
the chloride may be calculated in the same manner as chloride of 
ammonium, 5.85 grammes of chloride being equal to 10.28 grammes 
of bromide of,sodium. 
Cyanide of Potassium.—Operate upon from .1 to .2 gramme of 
the salt, conducting the titration as for hydrocyanic acid. The 
following reaction occurs :— 
10)130 
13 
2KCy + AgN03 = AgCy,KCy + KNOs 
10)169.7 
16.97 = l°d0 c.c. of standard solution. 
The United States Pharmacopoeia requires Cyanide of Potassium 
to contain 90 per cent, of real cyanide (KCy). 
Syrup of Hydriodic Acid.—Operate upon 10 to 15 grammes. 
The reaction which occurs is as follows:— 
Ill + AgNO, = Agl + IIN03 
10)127.6 
12.76 
10)169.7 
16.97 = 1000c.c. of standard solution. 
The close of the reaction is shown by the cessation of the formation 
of iodide of silver, the nitric acid liberated rendering chromate of 
potassium inadmissible as an indicator. 
Syrupus Acidi Hydriodici, U. S. P., should contain 1 per cent, 
of anhydrous hydriodic acid (HI). 
Syrup of Bromide of Iron.—About 1 gramme should be used :— 
FeBr2 + 2AgNOs = 2AgBr + Fe (N03)2 
20)215.5 
10.775 
20)339.4 
16.97 — 1000 c.c. of standard solution. 
It should correspond to 10 per cent, of bromide of iron (FeBr2) to 
fulfil the requirements of the United States Pharmacopoeia. ESTIMATION OF ACIDULOUS RADICALS. 
571 
Syrup of Iodide of Iron.—Operate upon 1 to 2 grammes of the 
syrup until no further precipitate is formed:— 
Fel, + 2AgN03 = 2AgI + Fe(NOs)2 
20)309.1 
15.455 
20)339.4 
16.97 = 1000c.c. of standard solution. 
Syrupus Ferri Iodidi, U. S. P., should contain 10 per cent, of 
iodide of iron (FeL,). 
Spirit of Wine (Spiritus liectificatus, B. P.) may contain traces 
of amylic alcohol and aldehyd ; these may be detected by nitrate of 
silver, which is reduced by them to the metallic state. Any quan- 
tity beyond a mere trace of such bodies renders spirit of wine too 
impure for use in medicine. “ Four tluidounces with thirty grain- 
measures (about 2 c.c.) of the volumetric solution of nitrate of 
silver exposed for twenty-four hours to bright light, and then de- 
canted from the black powder which has formed, undergoes no 
further change when again exposed to light with more of the test.” 
—B. P. “ If 20 c.c. are shaken in a glass-stoppered vial, previously 
well rinsed with the same alcohol, with 2 c.c. of test-solution of 
nitrate of silver, the mixture should not be rendered more than 
faintly opalescent during one day’s exposure to direct sunlight (abs. 
of more than traces of foreign organic matters, fusel oil, etc.).”— 
U. S. P. 
Iodide of Potassium may be volumetrically estimated by a semi- 
decinormal solution of mercuric chloride, the termination of the 
operation being indicated by the formation of a red precipitate:— 
(1) 4KI + HgCl2 = 2KC1 + IIgI2,2KI; 
(soluble) 
(2) HgI„2KI + IlgCl, = 2KC1 + 2HgI2. 
The author of this process, M. Personne, states that neither chlo- 
rides, bromides, nor carbonates interfere. Carles dissolves the 
iodide in spirit of wine of 171 per cent., as much excess of water 
decomposes the double iodide. 
Iodide of Iron.—Messrs. Naylor and Hooper have demonstrated 
that Personnel solution is applicable to ferrous iodide, even in the 
state of syrup :— 
(1) 2Fel2 + HgCl, = FeCl2 + FeT2,HgT2; 
(soluble) 
(2) FeI2,HgI2 + HgCl2 = FeCl2 + 2IIgIr 
997. Explain the volumetric method of estimating the strength 
of aqueous solutions of hydrocyanic acid. 
998. Work a sum showing how much nitrate of silver will indi- 
cate, by the official volumetric process, the presence of 1 part of 
real hydrocyanic acid. Am. 6.2853 parts. 
QUESTIONS AND EXERCISES. 572 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
ESTIMATION OF SUBSTANCES READILY OXIDIZED. 
Any deoxidizer—that is, any substance which quickly absorbs a 
definite amount of oxygon or is susceptible of any equivalent action 
—may be quantitatively tested by ascertaining how much of an 
oxidizing agent of known power must be added to a given quantity 
before complete oxidation is effected. The oxidizing agents em- 
ployed for this purpose in the United States Pharmacopoeia are 
iodine and the red chromate of potassium. Permanganate of potas- 
sium is often used for the same purpose. Iodine acts indirectly by 
taking hydrogen from water and liberating oxygen; the red chro- 
mate of potassium directly, by the facility with which it yields three- 
sevenths of its oxygen, as indicated by the equations and statements 
given on p. 575; permanganate of potassium, by affording five- 
eighths of its oxygen in presence of acid, 
2K2Mn208 + 0II2SO4 = 2K2S04 -f 4MnS04 + 6H20 + 502. 
Standard Solution of Iodine. 
(Iodine, I = 126.6.) 
If pure iodine be not at hand, it may be prepared by mixing the 
commercial article with about a fourth of its weight of iodide of 
potassium and subliming. Sublimation may be effected by gently 
warming the mixture in a beaker the mouth of which is closed 
by a funnel; the iodine vapor condenses on the funnel, while 
fixed impurities are left behind, and any chlorine which the 
iodine may contain is absorbed by the iodide of potassium, an 
equivalent quantity of iodine being liberated. Small quantities 
may be similarly treated between two watch-glasses placed edge to 
edge. Any trace of moisture in the resublimed iodine is removed 
by exposure for a few hours under a glass shade near a vessel con- 
taining oil of vitriol. 
Place 12.66 grammes of pure iodine and about 18 grammes of 
pure iodide of potassium (an aqueous solution of which is the best 
solvent of iodine; the salt plays no other part in these operations) 
in a litre flask, add a small quantity of water, and agitate until the 
iodine is dissolved; dilute to 1 litre. 
The following substances are officially estimated by this volu- 
metric solution:— 
Sulphurous Acid.—Operate on about .5 of a gramme of the acid, 
and dilute with water as usual. If the sulphurous acid be diluted 
to a less degree than .04 or .05 per cent., there will be some risk of 
the sulphuric acid formed being again reduced to sulphurous acid, 
with liberation of iodine. In delicate experiments the distilled 
water used for dilution should previously be freed from air by boil- 
ing, to prevent the small amount of oxidizing action which dissolved 
air would exert. The solution of iodine is then added until a slight 
permanent brown tint is produced, showing the presence of free 
iodine. A better indicator of the termination of the reaction is 
mucilage of starch, which gives a blue color with the slightest trace 
of free iodine. 
The following equations, etc. show the reaction that takes place:— ESTIMATION OF SUBSTANCES READILY OXIDIZED. 
H2S03 + ir20 + I2 = 2HI + II2S04 
20)82 
4.1 
20)253,2 
12.66 = grms. in 1000 c.c. of standard solution. 
II20,S02 + II20 + = 2III + II2S04 
20)64 
3.2 
20)253.2 
12.66 = grins, in 1000 c.c. of standard solution. 
The official (U. S. P.) sulphurous acid should contain 3.5 per 
cent, of sulphurous anhydride (S02). 
Arsenic.—About .1 gramme of solid arsenic, accurately weighed, 
should be dissolved in the usual quantity of water, heated to boil- 
ing, by help of about .5 gramme of bicarbonate of sodium. The 
arsenious acid is only partly, if at all, converted into arsenite or ar- 
seniate of sodium, but the iodine reaction occurs more readily in an 
alkaline solution. When the liquid is quite cold, mucilage of starch 
is added, and the iodine solution allowed to flow in until, after well 
stirring, a permanent blue color is produced. The official solution 
of arsenite of potassium, already containing some carbonate of 
potassium, requires somewhat less. 10 grammes is a convenient 
quantity to operate upon. To this should be added the usual quan- 
tity of water and about .3 of a gramme of bicarbonate of sodium. 
After boiling and cooling the titration is carried on as before.— 
About 10 grammes of the official solution of arsenic in dilute hydro- 
chloric acid is also a convenient quantity to operate upon. This 
quantity requires about .6 gramme of bicarbonate of sodium. The 
usual quantity of water is added, and the titration performed as be- 
fore. The following equation exhibits the reaction:— 
40)1 97.8 
4.945 
As203 + 5II20 + 2I2 = 4III + 2II3As04 
40)506.4 
12.66 = gnus, in 1000 c.c. of standard solution. 
Arsenic, U. S. P., should contain 97 per cent., and both solutions, 
U. S. P., contain .97 per cent, of arsenic. 
Hyposulphite of Sodium.—About .4 of a gramme is a convenient 
quantity to employ. It is dissolved in water, starch mucilage added, 
and the iodine solution slowly run in, the whole being frequently 
stirred, until a permanent blue color is produced. This is the B. P. 
process; the U. S. P. orders a solution of sodium hyposulphite to 
be shaken with solid iodine. 
In the previous reactions iodine has acted as an indirect oxidizing 
agent by uniting with the hydrogen and thus liberating the oxygen 
of water. In the present case it unites with an analogue of hydro- 
gen—namely, sodium—a new salt (tetrathionate of sodium) being 
simultaneously produced, thus :— 
2(N -f- I2 = 2XaI 4- Xa2S406 -j- 10II2O 
20)496 
24.8 
20)253.2 
12.66 = gmis. in 1000 c.c. of standard solution. 574 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
The United States Pharmacopoeia requires 98 per cent, purity in 
the case of hyposulphite of sodium. 
Sulphite of Potassium.—About .1 gramme is a convenient quan- 
tity to take, using starch paste as an indicator, as before. The re- 
action as below occurs :— 
K2S03,2H20 + I2 = 2KI + H2S04 + II20 
2.0)19.4 
” 9.7 
20)253.2 
12.66 = 1000 c.c. of standard solution. 
Sulphite of potassium, U. S. P., should contain 90 per cent, of the 
crystallized salt (K2S03,2H20). 
Bisulphite of Sodium.—Operate upon .05 to .07 gramme, as 
before:— 
NaTISOg + I2 + II20 = Nal + II2S04 + III 
20)104 
5.2 
20)253.2 
12.06 = 1000 c.c. of standard solution. 
The United States Pharmacopoeia requires bisulphite of sodium to 
contain 90 per cent, of the pure salt (NaHSOs). 
Sulphite of Sodium.—Use for this estimation about 1. to .15 
gramme, and proceed as before:— 
Na,SOs,711,0 + I2 = 2NaI + II,S04 + 611,0 
v / 
20)252 
12.6 
20)253.2 
12.66 = 1000 c.c. of standard solution. 
This also should contain 90 per cent, of the crystallized salt to sat- 
isfy the demands of the United States Pharmacopoeia. 
QUESTIONS AND EXERCISES. 
999. Give equations illustrative of the reactions on which the 
use of a standard volumetric solution of iodine is based. 
1000. From what point of view may iodine be regarded as an 
oxidizing agent? 
1001. What reagent indicates the termination of the reaction be- 
tween deoxidizing substances and moist iodine? 
1002. IIow much sulphurous acid gas will cause the absorption 
of 2.54 parts of iodine in the volumetric reaction? Ans. .642. 
1003. What quantity of iodine will be required, under appropri- 
ate conditions, to oxidize 5 parts of arsenic? Ans. 12.008. 
1004. Find by calculation the amount of hyposulphite of sodium and 
of sulphite of sodium which will react with 13 parts of iodine in 
volumetric analysis. Ans. 25.466 and 12.9384. RED CHROMATE OF POTASSIUM. 
575 
VOLUMETRIC SOLUTION OF RED CHROMATE OF 
POTASSIUM. 
(Red Chromate of Potassium, K2Cr207 = 294.8.) 
One molecule of red chromate of potassium in presence of an 
acid, under favorable circumstances, yields 4 atoms of oxygen to 
the hydrogen of the acid, leaving three available either for direct 
oxidation or for combination with the hydrogen of more acid, an 
equivalent proportion of acidulous radical being liberated for any 
required purpose. 
When used as a volumetric agent the red chromate always yields 
the whole of its oxygen to the hydrogen of the accompanying acid, 
a corresponding quantity of acidulous radicals being set free—four- 
sevenths of this radical immediately combining with the potassium 
and chromium of the red chromate, three-sevenths becoming avail- 
able. Ferrous may thus be converted into ferric salts with sufficient 
rapidity and exactitude to admit of the estimation of an unknown 
quantity of iron by a known quantity of the red chromate. As l 
atom of any liberated bivalent acidulous radical will convert 2 mole- 
cules of ferrous into l of ferric salt, 1 molecule of red chromate 
causes 6 of ferrous to become 3 of ferric, as shown in the following 
equation:— 
K2Cr04,Cr03 -f 7II2S04 + 6FeS04 = K2S04,Cr23S04 + 7H20 
The volumetric solution is made by dissolving 14.74 grammes 
(.jfi of a molecular weight in grammes) of red chromate of potas- 
sium in water, and diluting to 1 litre. It is used in determining 
the strength of the ferrous preparations. It is known that the 
whole of the ferrous has been converted to ferric salt when a small 
drop of the liquid placed in contact with a drop of a very dilute 
solution of ferridcyanide of potassium on a white plate ceases to 
strike a blue color. 
If the red chromate employed in making this standard solution is 
not known to be pure and dry, the strength of the solution may be 
checked by dissolving a small, accurately weighed piece of piano- 
forte wire (0.4 or 0.5 gramme) in diluted sulphuric acid in a small 
flask, warming, and then running in the solution of red chromate 
until conversion is effected. 
The reactions which take place may be thus expressed :— 
+ 3(Fe23S04). 
20)335.4 
16.77 
6Fe + 6II2S04 = 6FeS04 + 6H2 
20)91IA_ 
45.57 
6FeS04 + K2Cr207 + 7H2S04 = 
20)911.4 
45.57 
20)294.8 
14.74 = grammes in 1000 c.c. of standard solution. 
K2S04,Cr23S04 + 7H20 + 3(Fe23S04) VOLUMETRIC QUANTITATIVE ANALYSIS. 
It is evident that 16.77 grammes of iron are equivalent in the re- 
actions to 14.74 of red chromate or 1000 c.c, of standard solution of 
the chromate. Now suppose that 0.5 of a gramme of pianoforte wire 
has been employed, and the quantity of solution of red chromate of 
unknown strength used has been 28 c.c. How many c.c. of this solu- 
tion contain 14.74 of red chromate? that is, how many c.c. must be 
required to oxidize ferrous salt containing 16.77 of iron? As .5 of 
iron is to 28 c.c. sol., so are 16.77 of iron to x c.c. sol. = 939.12 c.c. 
Of the supposed solution, then, 939.12 c.c. would contain 14.74 
grammes of red chromate, and would be equivalent to 1000 c.c. of 
standard solution. It might be employed without being diluted, or, 
better, be diluted to official standard strength. 
Special care should be taken in all these estimations of substances 
readily oxidized to avoid atmospheric oxidation. Flasks may usually 
be loosely corked, or corked closely with a gas exit-tube passing just 
beneath a little mercury, and in all cases the estimation should be 
performed quickly. When standardizing with iron wire any slight 
oxidation may be remedied by a fragment of zinc, the last portions 
of which must be removed or dissolved before the titration is com- 
menced. 
The ferrous salt in the following substances is estimated by this 
solution. 
Arseniate of Iron.—Operate upon 1 to 2 grammes. Dissolve in 
excess of dilute sulphuric or hydrochloric acid. Sulphuric acid is 
preferable in most cases, because ferrous sulphate absorbs oxygen 
much less readily than ferrous chloride. The reaction that occurs 
is shown in the following equation, the ferrous arseniate being con- 
verted into ferric arseniate :— 
2(Fe//32As04) + 7II2S04 + K2Cr207 = 
20)891 
44.55 
20)294.8 
14.74 = grammes in 1000 c.c. of standard sol. 
K2S0i,Cr23S04 + Fe'" 3S04 + 2(Fe'"2As04) + 711./) 
Arseniate of Iron, B. P., is supposed to contain 37.9 per cent, of fer- 
rous arseniate. The compound is more nearly a ferric than a ferrous 
arseniate. 
Phosphate of Iron.—Operate upon 1 to 2 grammes. Proceed as 
with arseniate. The following equation indicates the reaction, the 
ferrous phosphate being converted into ferric phosphate:— 
2(Fe"2P04) + 7H2S04 + K2Cr20T = 
20)715.4 
35.77 
20)294.8 
14.74 = lOOO c.c. of standard solution. 
K2S04,Cr23S04 + Fe'" 3S04 + 2(Fe'"2P04) + 7H20 
The official (B. P.) requirement is nearly 45 per cent, of real ferrous 
phosphate. Phosphate of Iron, U. S. P., is Ferric Phosphate, and 
therefore cannot be estimated by this solution. RED CHROMATE OF POTASSIUM. 
577 
Saccharated Carbonate.—Proceed as with arseniate, using about 
the same quantity :— 
6FeC03 + 13II2S04 + K2Cr207 = 
20)695.4 
34.77 
20)2948 
14.74 = 1000 c.c. of standard solution. 
K2S04Cr23S04 + 3(Fe23S04) + 13II20 + 6C02 
The official (U. S. P.) strength is 15 per cent. Trade samples yield 
from 20 to 30, and sometimes 35, per cent., according to the care with 
which oxidation has been prevented. The theoretical percentage ob- 
tainable from the ingredients is 45.5, the quantity that would be 
present if the compounds were anhydrous and unoxidized—condi- 
tions never obtained in practice. Howie has suggested that as 
hydrochloric acid is known to so rapidly convert ordinary sugar 
into inverted sugar as to render it easily attacked by chromic acid, 
'while phosphoric acid very slowly affects sugar, the latter acid in- 
stead of the former should be employed in dissolving the saccharated 
carbonate of iron for volumetric analysis. Another mode of elim- 
inating the action of sugar is to char with oil of vitriol before 
analyzing. 
Magnetic Oxide of Iron.—Use about the same quantity, and pro- 
ceed as with arseniate or phosphate. The reaction may thus be 
shown :— 
6Fe304 -f- 31II2S04 -j- K2Cr207 = 
20)1390.2 
69.51 
20)294.8 
14.74 = grammes in 1000 c.c. of standard solution. 
K2S04,Cr23S04 + 9(Fe23S04) + 31H20 
or, 
6(Fe203,Fe0) + 31H2S04 + K2Cr207 = 
20)4344 
21.57 
20)2948 
14.74 = grammes in 1000 c.c. of stand, solution. 
K2S04,Cr23S04 + 9(Fe23S04) + 31II20 
Absolutely pure magnetic oxide of iron contains 31 per cent, of 
ferrous oxide. Oxidation occurs, however, during manufacture, as 
in the case of the ferrous salts just described. The British Pharma- 
copoeia recognizes magnetic oxide containing nearly 25 per cent, of 
ferrous oxide. 
Sulphate of Iron.—Operate upon about 1 gramme of the crystal- 
lized or precipitated salt in presence of excess of sulphuric acid; 
the reaction which occurs has been already given when treating 
of the standardizing of solution of Bichromate of Potassium on 
page 575. 
The United States Pharmacopoeia demands almost absolute 
purity for both Ferri Sulphas and Ferri Sulphas Precipitatus 
(FeS04,7H20). 578 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
Note.—The use of this volumetric solution in quantitative analysis 
admits of great extension. The student should at least employ it in 
the case of a few iron ores. 
1005. Write equations explanatory of the oxidizing power of red 
chromate of potassium. 
1006. One hundred cubic centimetres of an aqueous solution of 
red chromate of potassium contain of the molecular w eight of 
the salt in grammes ; with what weight of metallic iron, dissolved in 
hydrochloric acid, will this volume react? Ans. 1.677 grammes. 
1007. If 8.34 grammes of impure crystallized ferrous sulphate, 
dissolved in acidulated water, require 93 c.c. of the standard solution 
of chromate for complete conversion into ferric salt, what percentage 
of ferrous sulphate is present? Ans. 92.966. 
1008. Work a sum showing how much red chromate of potassium 
is required for the conversion of 10 parts of ferrous sulphate into 
ferric salt. Ans. 1.768. 
1009. Show what quantity of pure ferrous carbonate is indicated 
by 1.475 parts of red chromate as applied in volumetric analysis. 
Ans. 3.479. 
1010. Prove what amount of official saccharated carbonate of 
iron is equivalent to .7375 part of red chromate in the volumetric 
reaction. Ans. 11.598. 
QUESTIONS AND EXERCISES. 
ESTIMATION OF SUBSTANCES READILY DEOXIDIZED. 
Any substance which quickly yields a definite amount of oxygen 
may be quantitatively tested by ascertaining how much of a deoxi- 
dizing agent of known power must be added to a given quantity 
before complete deoxidation is effected. The chief compounds which 
may be used for this absorption of oxygen (deoxidizers or reducing 
agents, as they are commonly termed) are hyposulphite of sodium, 
sulphurous acid, ferrous sulphate,* oxalic acid, arsenious acid. The 
first named is officially employed; it is only used in the estimation 
of free iodine, and, indirectly, of chlorine and chlorinated compounds. 
Iodine and chlorine are regarded as oxidizing agents, because their 
great affinity for hydrogen enables them to become powerful indirect 
oxidizers in presence of water. 
Standard Solution op Hyposulphite of Sodium. 
(Crystallized Hyposulphite of Sodium, Na2S203,5H20 = 248.) 
Dissolve about 27 grammes of hyposulphite of sodium in a litre 
or less of water. Fill a burette with this solution, and allow it to 
* Five grains of permanganate of potassium dissolved in water re- 
quire for decoloration a solution of forty-four grains of granulated sul- 
phate of iron acidulated with two fluidraclims of diluted sulphuric 
acid. VOLUMETRIC ESTIMATION OF OXIDIZERS. 
flow into a beaker containing, say, 15 c.c. of the volumetric solution 
of iodine until the brown color of the iodine is just discharged, or, 
starch being added, until the blue iodide of starch is decolorized. 
(The latter affords the more delicate indication.) When iodine and 
hyposulphite of sodium react, 2 atoms of iodine remove 2 of sodium 
from 2 molecules of the hyposulphite, tetrathionate of sodium being 
formed, as indicated in the following equation:— 
+ 2(Na2S,03,5H,0) = 
20)253.2 
12.66 = grms. of iodine in 1000 c.c. 
20)496 _ 
24.8 = grms. of hypo, in 1000 c.c. 
2NaI + Na,S406 + 10II2O 
Now, suppose the number of c.c. required to deoxidize the 15 c.c. 
of standard iodine were 14 c.c., how many c.c. of this hyposulphite 
solution would be equivalent to 1000 c.c. of standard iodine solution ? 
In other words, how many c.c. would contain 24.8 grammes of hypo- 
sulphite? As 15 c.c. iodine sol. are to 14 c.c. hyposulph. sol., so 
are 1(XX) iodine sol. to x hyposulph. sol. = 933 c.c. Therefore, 933 
c.c. of this solution of hyposulphite would contain 24.8 grammes 
of the salt, and be equivalent to 1000 c.c. of the official standard 
solution. The 933 c.c. would be diluted to 1000 c.c., or be used 
without dilution. In either case its strength would, as usual, be 
recorded on the label. The following substances are estimated 
officially by means of this solution. 
Chlorine-Water.—About 10 grammes are operated upon. Excess 
of iodide of potassium is added; that is, to 10 grammes of solution 
of chlorine about half a gramme of iodide. An amount of iodine 
is set free by the chlorine exactly in proportion to their atomic 
weights. The titration is then conducted as already described. 
The following shows the reaction:— 
Cl2 + 2KI = I2 + 2KC1 
20)71 
3.55 
20)253.2 
12.66 
I2 + 2(Na2S203,5II20) = 2NaI + Na2S406 + 10II2O 
20)253.2 
” 12.66 
20)496 
24.8 = grammes in 1000 c.c. of standard solution. 
It is evident, then, that 1000 c.c. of standard solution of hypo- 
sulphite of sodium, or a corresponding quantity of a solution of 
different strength, is equivalent to 3.55 grammes of chlorine gas. 
Chlorine-Water of the United States Pharmacopoeia contains .4 per 
cent, of chlorine gas. 
Iodine.—Solid iodine is dissolved in solution of iodide of potas- 
sium, and titrated as already described. About .2 of a gramme is a 
convenient quantity to employ. 1000 c.c. of standard hyposulphite 
solution are equivalent, as seen in the equation, to 12.66 of iodine. 
The United States Pharmacopoeia requires “iodine” to contain 100 580 
VOLUMETRIC QUANTITATIVE ANALYSIS. 
per cent, of real iodine. It is assumed in this operation that the 
iodine has been shown by qualitative analysis to be free from chlo- 
rine and bromine. These elements resemble iodine in reacting 
upon hyposulphite of sodium, hence would reckon as iodine in a 
volumetric assay. 
Chlorinated Lime.—Operate on from .1 to .2 of a gramme. Dis- 
solve in the usual quantity of water, and add excess either of dilute 
hydrochloric or dilute sulphuric acid and of iodide of potassium: 
.1 to .2 of a gramme of chlorinated lime would require .4 to .8 of a 
gramme of iodide of potassium. The following equations show the 
reactions:— 
or, 
CaOCl2 + 1I2S04 == CaS04 + I120 + Cl2. 
CaOCI2 + 21IC1 = CaCl2 + II20 + Cl,; 
The chlorine thus set free liberates an equivalent amount of iodine, 
and this is titrated as before. (See the equations for solution of 
chlorine.) This chlorine, liberated from chlorinated lime by acids, 
is its available chlorine for indirect oxidizing action. It should 
correspond (U. S. P.) to 25 per cent. 
Solution of Chlorinated Lime.—About 2 grammes is a convenient 
quantity to operate upon. 1 gramme of iodide of potassium and 
excess of acid should be added, and the available chlorine deter- 
mined as in the case of the solid. The official (U. S. P.) require- 
ment is 2.9 per cent, of available chlorine. 
Solution of Chlorinated Soda.—About 2 grammes are mixed with 
the usual quantity of water, excess of acid added, and about 1 
gramme of iodide of potassium. The available chlorine is esti- 
mated as in the case of chlorinated lime. The reaction by which 
the chlorine is evolved is similar:— 
NaCl,NaOCl + 2IIC1 = 2NaCl + II20 + Cl2. 
The action of the liberated chlorine on the iodide of potassium 
and the iodine on the hyposulphite solution has been given under 
fi Solution of Chlorine.'1 The official (U. S. P.) requirement is 2 
per cent, of available chlorine. 
Compound Solution of Iodine.—Process as before, using 1 or 2 
grammes; the reaction has already been given. The requirements 
of the United States Pharmacopoeia are 5 per cent, of free iodine. 
Tincture of Iodine.—Use about 1 gramme. It will contain 8 per 
cent, of free iodine when of official strength. 
1015. For what purposes is the official volumetric solution of 
hyposulphite of sodium used? 
1016. On what reaction is based the quantitative employment of 
hyposulphite of sodium ? 
1017. How much hyposulphite of sodium is required to show the 
presence of 10 parts of iodine? Ans. 19.527. 
QUESTIONS AND EXERCISES. ESTIMATION OF POTASSIUM. 
581 
1018. To what amount of chlorine is 4.96 parts of hyposulphite 
of sodium equivalent in volumetric analysis? Ans. 0.71. 
1019. Describe the operation included in the estimation of the 
Strength of bleaching-powder. 
1020. By what reagent is the complete absorption of free iodine 
by hyposulphite of sodium indicated? 
MISCELLANEOUS PROBLEMS. 
1021. Work sums showing how much bicarbonate of potassium 
is contained in an eight-ounce bottle of medicine, seven fluidrachms 
of which are saturated by two and a half grains of crystallized 
oxalic acid. Am. 36.3 grains. 
1022. A sample of soda-ash is said to contain 78 per cent, of pure 
anhydrous carbonate of sodium ; if the statement is true, how much 
of the official volumetric solution of oxalic acid will saturate 5 
grammes of the specimen? Am. 73.6. 
1023. 2.69 grammes of common brown sulphuric acid are satu- 
rated by 43.5 cubic centimetres of the official volumetric solution of 
soda •, how much acid of 96.8 per cent, is present ? Am. The 2.69 
contained 2.2. 
1024. Four grammes of a litre and a half of concentrated hydro- 
cyanic acid are neutralized by 89 cubic centimetres of volumetric 
solution of nitrate of silver of official strength by the official process : 
to what volume must the bulk of the acid be diluted for the produc- 
tion of acid of pharmacopceial strength ? Ans. 4J litres. 
1025. 3.18 grammes of a powder containing arsenic require for 
complete reaction 84 cubic centimetres of a volumetric solution of 
iodine, which is 1.43 per cent, weaker than the standard solution of 
the United States Pharmacopoeia; what percentage of pure arsenic 
is contained in the powder ? Aws. 12.863. 
1026. How much pure metal is present in a sample of iron 1.68 
of a gramme of which, dissolved in dilute sulphuric acid, is exactly 
attacked by 95.7 cubic centimetres of semi-decinormal volumetric 
solution of red chromate of potassium which is 6 per cent, too 
strong ? 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
ESTIMATION OF METALS. 
Outline of the Process.—This element is usually estimated in the 
form of double chloride of potassium and platinum. Qualitative 
analysis having proved the presence of potassium and other radi- 
cals in a substance, a small quantity of the material is accurately 
weighed, dissolved, and the other elements removed by appropriate 
reagents; the precipitates are well washed, in order that no trace 
POTASSIUM. 582 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
of the potassium salt shall be lost, the resulting liquid concentrated 
over a water-bath (to avoid loss that would occur mechanically 
during ebullition), hydrocholoric acid added if necessary, solution of 
perchloride of platinum poured in, and evaporation continued to 
dryness; excess of the perchloride is then dissolved out by adding 
to the dried residue spirit of wine containing half its bulk of ether 
(a liquid in which the double chloride is insoluble), the mixture 
carefully poured on to a tared and dried filter, washed with the spirit 
till every trace of free perchloride of platinum is removed, the whole 
dried and weighed; from the resulting amount the proportion of 
potassium, or equivalent quantity of a salt of potassium, is ascer- 
tained by calculation. 
Note.—From this short description it will be seen, first, that the 
chemistry of quantitative is the same as that of qualitative analysis ; 
second, that the principle of gravimetric is the same as that of 
volumetric quantitative analysis: the combining proportions being 
known, unknown quantities of elements may be ascertained by 
calculation from known quantities of their compounds. 
Apparatus.—In addition to a delicate balance and weights 
and the common utensils, a few special instruments are used in 
quantitative manipulation ; some of these may be prepared 
before proceeding with the estimation of potassium. 
Filteriny-paper may be of the kind known as “ Swedish,” 
the texture of which is of the requsite degree of closeness 
and its ash small in amount. A large number of circular pieces 
of one size, six to eight centimetres in diameter, should be cut 
ready for use. In delicate experiments, where a precipitate on 
a filter has to be ignited and the paper consequently burnt, the 
weight of the ash of the filter must be deducted from the weight 
of the residue. The ash is estimated after burning ten or 
twenty of the cut filters. These are folded into a small com- 
pass, a portion of a piece of platinum wire twisted a few times 
round the packet, so as to form a cage, the whole held by the 
free end of the wire over a weighed porcelain crucible placed 
in the centre of a sheet of glazed paper, the bundle ignited by 
a spirit-lamp or smokeless gas-flame, the flame allowed to im- 
pinge against the charred mass till it falls into the crucible 
below, any stray fragments on the sheet carefully shaken into 
the crucible, the latter placed over a flame till carbon has all 
burnt off and nothing but ash remains, the whole cooled, 
weighed, and the weight of the crucible deducted; the weight 
of the residue divided by the number of pieces used gives the 
average amount of ash in each filter. 
A pair of weighing-tubes (Fig. 74), for holding dried filters 
during operations at the balance, may be made from two test- 
tubes, one fitting closely within the other. About five cen- ESTIMATION OF POTASSIUM. 
583 
timetres of the closed end of the outer and seven of the 
inner are cut oif by leading a crack round the tube with a 
Fig. 74. 
Fig. 75. 
pencil of incandescent charcoal, and the sharp edges fused in 
the blowpipe-flame. A filter, after drying, is quickly folded 
and placed in the narrower tube, the mouth of which is then 
closed by the wider tube. This prevents reabsorption of moist- 
ure from the air. 
A 'pair of watch-glasses, having accurately ground edges 
and clamped, as shown in Fig. 75, also form 
a convenient arrangement for weighing fil- 
ters, etc. 
The washing-bottle, holding the spirit of 
wine and ether, is a common flask through 
the cork of which a short straight tube passes. 
The outer end of the tube should be suffi- 
ciently narrowed to enable it to deliver a 
very fine stream of the liquid. The flask 
being inverted, the warmth of the hand ex- 
pands the air and vapor to a sufficient extent 
to force out the liquid. 
The ordinary washing-bottle for quantitative operations should 
be formed of a flask in which water may be boiled, fitted up as 
usual f ide p. 107). 
A water-oven is the best form of drying-apparatus. It is a small 
square copper vessel, jacketed on five sides and having a door on the 
sixth; water is poured into the space between the inner and outer 
casing, and the whole placed over a gas-lamp or source of heat, 
moist air and steam escaping by appropriate apertures. Desiccation 
at higher temperatures than the boiling-point of water may be prac- 
tised by using oil or paraffin instead of water, inserting a ther- 
mometer in the fat. The apparatus may be purchased of any maker 
of chemical instruments. ' 
Pure distilled water must be used in all quantitative determina- 
tions. 
Note.—In practising the operations of quantitative analysis, ex- 
periments should at first be conducted on definite salts of known 
composition, for the accuracy of results may then be tested by 
calculation. 
Estimation of Potassium in the Form of Double Chloride of 
A pair of weighing-tubes. 
Clamped watch-glass for weighing. 
Fig. 76. 
The washing-bjttla. 584 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
Potassium and Platinum.—Select two or three crystals of pure 
nitrate of potassium, powder them in a clean mortar, dry the 
powder by gently heating in a porcelain crucible over a flame 
for a few seconds, place about a couple of decigrammes (0.2 
grm.) of the powder in a counterpoised watch-glass, accurately 
weigh the selected quantity, transfer to a small dish, letting 
water from a wash-bottle flow over the watch-glass and run 
into the dish, warm the dish till the nitrate is dissolved, acid- 
ulate with hydrochloric acid, add excess of aqueous solution of 
perchloride of platinum (a quantity containing about 0.4 of 
solid salt), evaporate to dryness over a water-bath. While 
evaporation is going on place a filter and the weighing-tubes 
in the water-oven, exposing them to a temperature of 100° C. 
for about half an hour ; fold the filter and insert it in the tubes, 
place them on a plate under a glass shade, and when cold 
accurately note their weight. Arrange the weighed filter in a 
funnel over a beaker. Transfer the dried and cooled platinum 
salt from the dish to the filter by moistening the residue with 
the mixture of alcohol and ether, and when the salt is loosened 
pouring the contents of the dish into the paper cone. Any 
salt still adhering may be freed by the finger, which, together 
with the dish, should be washed in the stream of spirit, the 
rinsings at once flowing into the filter. The filtrate should 
have a yellowish-brown color, due to the excess of perchloride 
of platinum. If it is colorless, an insufficient amount of per- 
chloride has been added, and the whole operation must be 
repeated. The washed precipitate and filter are finally dried 
in the water-oven, folded and placed in the weighing-tubes, the 
drying continued until the whole, after repeated weighing when 
cold, ceases to alter; the final weight is noted. 
Note.—If filters are not freed from all trace of acid by thorough 
washing, the paper will be brittle when dry, falling to pieces on being 
folded. 
Analytical memoranda in the note-book may have the fol- 
lowing form :— 
Watch-glass and substance 
Watch-glass 
Substance .... 
Weighing tubes, filter, and Pt salt . . . 
Weighing tubes and filter 
PtCl4,2KCl . . . ESTIMATION OF POTASSIUM. 
585 
The calculations are simple :— 
As 
PtCl4,2KCl 
= 484.8 
are equivalent to 
\ 2KNO:j 
i =202 
so 
the weight of 
double chloride 
obtained 
7 
- is equivalent to x. x will Be the amount 
of pure nitrate of potassium in the quantity of substance ope- 
rated on. x should, in the present instance, be identical with 
the weight of substance taken, because, for educational pur- 
poses, pure nitre is under examination. Only after analyses of 
pure substances have yielded the operator results identical with 
those by calculation can analyses of substances of unknown 
degree of purity be undertaken with confidence. A Table of 
Atomic Weights, from which to find molecular weights, is given 
in the Appendix. 
Platinum residues should be preserved, and the metal recovered 
from them from time to time (vide p. 245). 
Hot alcohol sometimes reduces perchloride of platinum, the metal 
being thrown out of solution in a finely-divided form known as plati- 
num black ; only aqueous solutions, therefore, of the salt should be 
used where heat is employed. Hence, also, in washing out excess of 
perchloride of platinum from the double chloride of platinum and 
potassium by spirit the application of heat should be avoided. 
Effervescing Potash-water (Liquor Potassce Efferrescens, B. P.) 
is most easily estimated volumetrically (p. 561). Any adulteration 
by an equivalent amount of bicarbonate of sodium would, however, 
by that process be undetected ; hence the Pharmacopoeia directs that 
“ 5 fluidounces, evaporated to one-fifth, and 12 grains of tartaric 
acid added, yield a crystalline precipitate which, when dried, weighs 
not less than 12 grains.” Five fluidounces of this preparation should 
contain 7.5 grains of bicarbonate, convertible into 14.1 grains of acid 
tartrate of potassium by 11.25 grains of tartaric acid. The method 
is somewhat rough, but quite efficient for “ potash-water ” containing 
nothing but bicarbonates of alkali-metals. 
Proportional Weights of Equivalent Quantities of Potassium 
and its Saifs. 
Metal ........ K, 78 
Oxide (“potash”) .... K.20 94 
Hydrate (“ caustic potash ”) 2KHO 112 
Carbonate (anhydrous) . . K2C03 138 
Carbonate (crystalline) . . K2C03 + 16 % aq. . 164.285 
Bicarbonate 2KHCOs .... 200 
Nitrate 2KNO;j 202 
Platinum salt PtCl4,2KCl . . . 484.8 586 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
Sodium is usually estimated as sulphate. Accurately weigh 
a porcelain crucible and lid, place within about .3 grm. of pure 
rock-salt, and again weigh, making a memorandum of the weights 
in a note-book. Add rather more strong sulphuric acid than 
may be considered sufficient to convert the chloride into acid 
sulphate of sodium. Heat the crucible gradually, the flame 
being first directed against the side of the crucible to avoid 
violent ebullition, until fumes of acid cease to be evolved, 
toward the end of the operation dropping in one or two frag- 
ments of carbonate of ammonium to facilitate complete expul- 
sion of all excess of acid. When cold, weigh the crucible and 
contents. The weight of the crucible having been deducted, 
the amount of sulphate obtained should be the exact equivalent 
of the quantity of chloride of sodium employed. 
SODIUM. 
2NaCl + II2S04 = Na2S04 + 2HC1. 
117 
142 
Proportional Weights of Equivalent Quantities of Sodium and 
its Salts. 
Metal Na2 46 
Oxide (“ soda ”) Na20 62 
Hydrate (“ caustic soda ”) . . 2NaHO .... 80 
Carbonate (anhydrous) .... Na2C03 .... 106 
Carbonate (crystals) Na2CO3,10H2O. . 286 
Bicarbonate 2NaHC03 . . . 168 
Chloride 2NaCl .... 116.8 
Sulphate (anhydrous) .... Na2S04 .... 142 
Sulphate (crystals) Na2SO4,10H2O. . 322 
AMMONIUM. 
Salts of ammonium are, for purposes of quantitative analysis, 
generally converted into the double chloride of ammonium and 
platinum (PtCl4,2NH4Cl), the details of manipulation being the 
same as those observed in the case of potassium. About 0.15 
grm. of pure, white, dry chloride of ammonium may be taken 
for experiment. 
Composition of the Platinum Salt. 
Pt . . 
. 194.4 
In 1 molec. wt. 
. . 194.4 . . 
In 100 parts. 
. 43.903 
Cl, . . 
. 35.4 X 6 • 
. . 212.4 . . 
. 47.967 
N2 . . 
. 14.0 X 2 . 
. . 28 
. 6.324 
H8 • • 
1.0 X 8 • 
8 . . 
. 1.806 
442.8 
100.000 ESTIMATION OF BARIUM. 
587 
In 1 molec. wt. 
In 100 parts. 
or, PtCl4 . 
. 336 
. . 336 
. 75.88 
2NII4C1 , 
. 53.4 X 2 . 
. . 106.8 . . 
. 24.12 
442.8 
100.00 
The proportion of nitrogen, ammonium, or chloride of am- 
monium in the double chloride may also be ascertained from 
the weight of platinum left on igniting the double chloride ; for 
this purpose heat must be applied slowly, or platinum will be 
mechanically carried oft with the gaseous products of decom- 
position. 
Proportional Weights of Equivalent Quantities of Ammoniacal 
Compounds. 
Ammonia (gas) 2NHS .... 34 
Ammonium (NH4),?. ... 36 
Chloride of ammonium .... 2NH4C1 .... 106.8 
Platinum salt PtCl4,2NH4Cl . . 442.8 
“ Carbonate of ammonium” . . (N4H1SC308) -h 2 . 118 
Sulphate of ammonium .... (Nil4)2S04 . . . 132 
Barium is estimated in the form of anhydrous sulphate of 
barium (BaS04). 
Process.—Dissolve 0.3 or 0.4 grm. of pure crystallized and dried 
chloride or nitrate of barium in about half a litre of water in a 
beaker, heating to incipient ebullition, and slightly acidulating 
with hydrochloric or nitric acid. Add diluted sulphuric acid 
(prepared some days previously, so that sulphate of lead may 
have deposited) so long as a precipitate forms; keep the mix- 
ture hot for some time, set aside for half an hour, pass the 
supernatant liquid through a filter, gently boil the residue two 
or three times with more water; finally, collect the precipitate 
on the filter, removing adherent particles from the beaker by 
the finger and cleansing by a stream of hot water from the 
wash-bottle. The precipitate must be washed with hot water 
until the filtrate ceases to turn litmus-paper red or give any 
cloudiness when tested with chloride of barium. The filter and 
sulphate of barium, having thoroughly drained, are dried in a 
warm place, commonly by supporting the funnel in an inverted 
bottomless beaker over a sand-bath or hot plate. 
The sulphate of barium is now removed from the filter, 
heated to drive off every trace of moisture, and weighed. This 
is accomplished by placing a weighed porcelain crucible (and 
cover) on a sheet of glazed paper, holding the filter over it, 
BARIUM. GRAVIMETRIC QUANTITATIVE ANALYSIS. 
and carefully transferring the precipitate; the sides of the 
filter are then gently rubbed together and detached powder 
dropped into the crucible, the paper folded, encased in two or 
three coils of one end of a platinum wire and burnt over the 
crucible, ash and any particles in the sheet of paper dropped 
into the sulphate of barium, the open crucible exposed over a 
flame till its contents are quite white, covered, cooled, and 
weighed. 
Chloride of barium . 
Formulae. 
Molecular 
weights. 
. . BaCl2,2H20 . 
243.6 
Nitrate of barium . 
. . Ba2N0, 
260.8 
Sulphate of barium 
. . BaS04 
232.8 
Ba . . 
In 1 
molec. wt. 
In 100 
pails. 
. . . 13G.8. . 
. . 136.8 
. 58.77 
S . . . 
. . . 32 . . 
. . 32 . 
. 13.73 
O4 • • 
. . . 16X4. 
. . 64 . 
232^8 
. 27.50 
100.00 
Composition of Sulphate of Barium. 
In these educational experiments it is unnecessary to take 
filter-ash into account. Inevitable mistakes of manipulation 
commonly cause far greater errors. 
CALCIUM. 
Calcium is usually thrown out of solution in the form of oxa- 
late, the precipitate ignited, and the resulting carbonate weighed. 
Process.—Dissolve 0.3 grm. or 0.4 of dried colorless crystals 
of calc-spar in about a third of a litre of water acidulated with 
hydrochloric acid, heat the solution to near the boiling-point, 
add excess of solution of oxalate of ammonium, then ammonia, 
until, after stirring, the liquid smells strongly ammoniacal; set 
aside in a warm place for twelve hours. Carefully pour off 
the supernatant liquid, passing it through a filter; add hot 
water to the precipitate, set aside for half an hour, again 
decant, and after once more washing transfer the precipitate to 
the filter, allowing all contained fluid to pass through before a 
fresh portion is added. Wash the precipitate with hot water, 
avoiding a rapid stream or the precipitate may "be driven 
through the pores of the paper. Dry, transfer to a weighed 
crucible, and incinerate, as described for sulphate of barium, 
and slowly heat the precipitate till the bottom of the crucible 
is just visibly red when seen in the dark. As soon as the ESTIMATION OF MAGNESIUM. 
589 
residue is white or only faintly gray remove the lamp, cool, 
and weigh. 
The resulting carbonate of calcium should have the same 
weight as the calc-spar from which it was obtained. If loss 
has occurred, carbonic acid gas has probably escaped. In 
that case moisten the residue with water, and after a few 
minutes test the liquid with red litmus- or turmeric-paper; if 
an alkaline reaction is noticed, it is due to the presence of 
caustic lime. Add a small lump of carbonate of ammonium, 
evaporate to dryness over a water-bath, and again ignite, this 
time being careful not to go beyond the prescribed temperature. 
The treatment may, if necessary be repeated. 
Proportional Weights of Equivalent Quantities of Calcium 
Salts. 
Oxide (quicklime) CaO 56 
Hydrate (slaked lime) .... Ca2HO . . . . 74 
Carbonate CaCO., . . . .100 
Sulphate (anhydrous) CaS04 .... 136 
Sulphate (crystalline or precipitated) CaS04,2H20 . . 172 
Chloride CaCl2 . ’. . .111 
Phosphate (of bone) (Ca32PO4)310 -4- 3 103.3 
Superphosphate ....... CaH42P04 . . . 234 
Process 1.— The light or heavy carbonate of magnesium of 
pharmacy may be estimated by heating a weighed quantity to 
redness in a porcelain crucible. If it has the composition 
indicated by the formula given in the British Pharmacopoeia 
(3MgC03,Mg2H0,4H20), it will yield 42 per cent, of mag- 
nesia (MgO). According to that work, the purity of even 
sulphate of magnesium (MgS04,7H20) may be determined by 
boiling a weighed quantity with excess of carbonate of sodium, 
collecting the precipitate, washing, drying, igniting, and weigh- 
ing the resulting magnesia (MgO). The crystalline sulphate 
should afford 16.2G per cent, of oxide. The official solution of 
carbonate of magnesium in carbonic acid water (Liquor Mag- 
netise Carbonatis, B. P.) should yield five grains of pure oxide 
of magnesium per fluidounce. 
Process 2.— The general form in which magnesium is precip- 
itated is as phosphate of ammonium and magnesium (MgN 
H,P04,6Hr,0) ; this, by heat, is converted into pyrophosphate 
of magnesium (Mg2P.,07). Accurately weigh a small quantity 
(0.4 to 0.5 grm.) of pure dry crystals of sulphate of magne- 
MAGNESIUM. 590 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
sium, dissolve in two or three hundred cubic centimetres of cold 
water in a beaker, add chloride of ammonium, ammonia, and 
phosphate of sodium or ammonium, agitate with a glass rod 
(without touching the sides of the vessel, or crystals will firmly 
adhere to the rubbed portions), and set aside for twelve hours. 
Collect on a filter, wash the precipitate with water containing 
a tenth of its volume of the strongest solution of ammonia, 
until the filtrate ceases to give a precipitate with an acidulated 
solution of nitrate of silver. Dry, transfer to a crucible, burn 
the filter in the usual way, heat slowly to redness, cool, and 
weigh. 
Proportional Weights of Equivalent Quantities of Magnesium 
Salts. 
Pyrophosphate . . Mg2P207 222 
Sulphate .... 2(MgS04,7H20) 492 
Oxide 2(MgO) 80 
Official carbonate . (3MgC03,Mg2H0;4H20) . , 191 
ZINC. 
Zinc is usually estimated as oxide (ZnO), occasionally as 
sulphide (ZnS). 
Process.—Dissolve a weighed quantity (0.5 to 0 6grm.) of sul- 
phate of zinc in about half a litre of water in a beaker, heat to 
near the boiling-point, add carbonate of sodium in slight excess, 
boil, set aside for a short time; pass the supernatant liquid 
through a filter, gently boil the precipitate with more water, 
again decant; repeat these operations two or three times; col- 
lect the precipitate on the filter, wash, dry, transfer to a 
crucible, incinerate, ignite, cool, and weigh. 286.9 (= molec. 
weight) of sulphate should yield 80.9 (= molec. weight) of 
oxide. 
MANGANESE. 
To ascertain its value for evolving chlorine from hydrochloric 
acid a weighed quantity of finely-powdered black oxide of 
manganese is heated in a small flask with pure hydrochloric 
acid, and the resulting chlorine conveyed into a U-tube con- 
taining solution of iodide of potassium. The amount of iodine 
thus freed is estimated by the volumetric solution of hypo- 
sulphite of sodium. 126.6 of iodine indicate 35.4 of chlorine. 
Manganese may also be estimated by the reaction and apparatus 
described under “ Oxalates,” page 607- (See Fig. 77). ESTIMATION OF ALUMINIUM. 
591 
Fig. 77. 
ALUMINIUM. 
Aluminium is always precipitated as hydrate (Al26IIO) and 
weighed as oxide (A1203). 
Process.—Dissolve about 2 grammes of pure dry ammonium 
alum in half a litre of water, heat the solution, add chloride 
of ammonium and a slight excess of ammonia, boil gently till 
the odor of ammonia has nearly disappeared, set aside for the 
hydrate to deposit, pass the supernatant liquid through a filter, 
wash the precipitate three or four times by decantation, trans- 
fer to the filter, finish the washing, dry, burn the filter, ignite 
in a covered crucible, and weigh. 
A123S04K2S04,24H20 948 
A123S04,(NH4)2S04,24H20 907 
AljOs . . 103 
Per cent, of A1203 yielded by ammonium alum . . 11,356 
QUESTIONS AND EXERCISES. 
1027. Give details of the manipulations observed in gravimetric- 
ally estimating salts of potassium or ammonium. 
1028. What quantity of chloride of sodium is contained in a sam- 
ple of rock-salt 0.351 gramme of which yields 0.426 of sulphate of 
sodium ? Jus. 99.83 per cent. 
1029. To what amount of the official alum is 0.894 of a gramme 
of the double chloride of platinum and potassium equivalent? Ans. 
1.748 grammes. 
1030. Find the weight of sulphate of barium obtainable from 
0.522 of nitrate. Ans. 0.466. 
1031. Describe the usual method by which salts of calcium are 
estimated. 
1032. By what quantitative processes may the official salts of 
magnesium be analyzed? 592 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
1033. Calculate the proportion of pure sulphate of zinc in a sam- 
ple of crystals 0.574 of which yield 0.161 of oxide. Ans. 99.46 per 
cent. 
1034. Ascertain the weight of alumina (Al2Os) which should be 
obtained from 1.814 grammes of ammonium alum. 
IRON. 
Iron and its salt are gravimetrically estimated in the form 
of ferric oxide (Fe20;j). 
Compounds containing organic acidulous radicals are simply 
incinerated, and the resulting oxide weighed. Thus, 1 gramme 
of the official citrate of iron and ammonium (Ferriet Ammoniac 
Cifras, B. P.), incinerated, with exposure to air, leaves not 
less than .27 of ferric oxide. A small quantity of the salt is 
weighed in a tared covered porcelain crucible, flame cautiously 
applied until vapors cease to be evolved, the lid then removed, 
the crucible slightly inclined and exposed to a red heat until 
all carbonaceous matter has disappeared. The residual ferric 
oxide is then weighed. The tartrate of potassium and iron 
(Ferrum Tar tar at um, B. P.) is treated in the same manner, 
except that the ash must be washed and again heated before 
weighing, in order to remove carbonate of potassium produced 
during incineration : 5 grammes should yield 1.5 grammes of 
ferric oxide. 
From other compounds of iron, soluble in water or acid, the 
metal is precipitated in the form of hydrate (Fe2GIIO) by solu- 
tion of ammonia, and converted into oxide (Fe2603) by ignition. 
Dissolve a piece (about 0.2 grin.) of the purest iron obtainable 
(piano wire), accurately weighed, in water acidulated with 
hydrochloric acid; add a few drops of nitric acid and gently 
boil; pour in excess of ammonia, stir, set aside till the ferric 
hydrate has deposited, pass the supernatant liquid through a 
filter, treat the precipitate three or four times with boiling 
water; transfer to the filter, wash till the filtrate yields no 
trace of chlorine (for chloride of ammonium will decompose 
ignited ferric oxide, with volatilization of ferric chloride), dry 
and ignite as usual, and weigh. Iron in the official solutions 
(Liquor Ferri Perchloridi Fortior, Liquor Ferri Nitratis, and 
Liquor Ferri Tersulpliatis) may be estimated by this general 
process. 
The proportion of metallic iron in a mixture of iron and ox- 
ides of iron may be determined by digestion in a strong solu- 
tion of iodine in iodide of potassium, which attacks the metal 
only. The reduced iron of pharmacy (Ferrum Redaction) is ESTIMATION OF ARSENICUM. 
593 
in good condition so long as it contains, as shown by this 
method, half its weight of free metal. 
Another Method—Reduced iron is converted into ferrous 
chloride by a hot, strong solution of Corrosive sublimate, while 
the oxides are not affected. The filtrate may be treated gravi- 
metrically or volumetrically (Wilner). 
Proportional Wrights of Equivalent Quantities of Iron and its 
Salts. 
Metal Fe, 111.8 
Ferric oxide .... Fe203 159.8 
Ferric hydrate . . . Fes6HO .... 218.8 
Ferric chloride . . . Fe2Cl6 324.2 
Ferric sulphate . . . Fe23S04 .... 399.8 
Ferrous sulphate . . 2(FeS04,7H20) . . 555.8 
Arsenic (As203) is usually estimated volumetrically (vide p. 
573). With certain precautions arsenicum may also be pre- 
cipitated and weighed as sulphide (As2S3). 
Process 1.—The pure, white, massive arsenic (about 0.2 grm.) 
is dissolved in a flask in a small quantity of water containing 
bicarbonate of sodium or potassium, the liquid being heated. 
A slight excess of hydrochloric acid is then added, and sur- 
phuretted hydrogen gas passed through the solution so long as 
a precipitate falls, the mouth of the flask being stopped by a 
plug of cotton-wool (to prevent undue access of air and conse- 
quent decomposition of the gas, resulting in precipitation of 
sulphur). The mixture is warmed in the flask, and carbonic 
acid gas passed through it until the odor of sulphuretted hydro- 
gen has nearly disappeared ; the precipitate collected on a tared 
filter, washed as quickly as possible with hot water containing 
a little sulphuretted hydrogen, dried in a water-oven, and 
weighed. 197.8 parts of arsenic should yield 245.8 of sul- 
phide of arsenicum. 
Process 2.—The arsenicum must be present in the arsemc 
condition. If the operator is not certain that this is the case, 
the solution must be warmed with a little hydrochloric acid 
and a few grains of chlorate of potassium added until a distinct 
odor of chlorous vapor is evolved, which is then allowed to 
escape by continued application of heat. To the solution 
thus obtained ammonia, which must produce no turbidity, is 
added in excess, and then magnesia mixture (see p. 608). The 
solution is set aside for twenty-four or forty-eight hours. The 
ARSENICUM. 594 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
precipitate is collected on a filter and washed with as little 
ammonia-water (1 to 3) as possible until the filtrate ceases to 
give a reaction for chlorides. The precipitate is then dried on 
the filter, the precipitate and filter-paper burned, and the whole 
gently ignited in a crucible and weighed. The residue is rep- 
resented by the formula (Mg^As307). 
ANTIMONY. 
The metal is precipitated in the form of sulphide (Sb2S3), 
with the precautions observed in estimating arsenicum, a small 
quantity of tartaric acid, as well as hydrochloric, being added 
to prevent the precipitation of an oxysalt. If the sulphuretted 
hydrogen be passed through a hot solution, the particles of pre- 
cipitate aggregate better, and the latter may he more quickly 
fdtered out and washed. Tha experiment may be performed 
on about half a gramme of pure tartar-emetic : the salt should 
yield slightly more than half its weight (50.6 per cent.) of 
sulphide. According to Fresenius, the sulphide dried at 100° 
C. still contains 2 per cent, of water, and must be heated in a 
current of carbonic acid gas until it turns from an orange to a 
black color before all moisture is expelled. In the United 
States Pharmacopoeia the purity of tartar-emetic (Antimonium 
Tartaratum) and the strength of solution of chloride of anti- 
mony (Liquor Antimonn Chloridi) are determined by the 
above process. Sulphurated Antimony of official quality, when 
dissolved in hydrochloric acid and the solution boiled and 
poured into a considerable volume of water, should yield a 
precipitate of oxychloride, which, after washing and drying, 
should weigh 85 per cent, of the sulphurated antimony. 
Copper is precipitated from its solutions and weighed (1) as 
metal (Cu2) or (2) as oxide (CuO). 
Process 1.—Dissolve about half a gramme of dry crystal- 
lized sulphate of copper in a small quantity of water in a tared 
porcelain crucible or beaker, acidulate with hydrochloric acid, 
introduce a fragment or two of pure zinc, cover the vessel with 
a watch-glass, and set aside till evolution of hydrogen has 
ceased and the still acid liquid is colorless. The copper is 
then washed with hot water by decantation until no trace of 
acid remains, the precipitate drained, rinsed with strong spirit 
of wine, dried in the water-oven, and weighed. 
Process 2.—About three-fourths of a gramme of sulphate 
of copper is accurately wreighed, dissolved in half a litre of 
COPPER. ESTIMATION OF MERCURY. 
water, the liquid boiled ; dilute solution of potash or soda is 
then added till no more precipitate falls, ebullition continued 
for a short time, and the beaker set aside; the supernatant 
liquid is decanted, the precipitate boiled with water, twice or 
thrice collected on a filter, washed, dried, transferred to a cru- 
cible, the filter incinerated, and its ash moistened with a drop 
of nitric acid; the whole is finally heated strongly, cooled, and 
weighed. 
Process 3.—From a solution acidulated by sulphuric acid 
and placed in a platinum crucible copper may be entirely de- 
posited in a coherent form by a weak current of electricity, 
the crucible being connected with the zinc pole of the battery, 
a platinum spatula suspended in the solution forming the posi- 
tive pole. The crucible may afterward be freed from the de- 
posited copper by nitric acid. 
249.2 parts of sulphate of copper yield 79.2 of oxide or 
G3 2 of metal. 
Other Processes.— Vide Pharmaceutical Journal for April 3, 
1880, p. 801. 
BISMUTH. 
Dissolve 0.3 or 0.4 grm. of pure oxycarbonate of bismuth 
(2Bi2O2C0.;.IlX)) (Bismuth! Subcarbonas, U. S. P.) in a small 
quantity of hydrochloric acid, dilute with water slightly acidu- 
lated by hydrochloric acid, pass excess of sulphuretted hydro- 
gen through the liquid, collect the precipitate on a fared filter, 
wash, dry at 100° 0., and weigh. The sulphide must not be 
exposed too long in the water-oven, or it will increase in 
weight, owing to absorption of oxygen; hence it should be 
tested in the balance every half hour during desiccation. 521 
of oxycarbonate should yield 51G of sulphide (Bi2S3). The 
atomic weight of bismuth is 210. 
MERCURY. 
This element may be (1) isolated and estimated in the form 
of metal, or precipitated and weighed as (2) mercurous chlo- 
ride, or (3) mercuric sulphide. 
Process 1.—The process by which the metal itself is sepa- 
rated is one of distillation into a bulb surrounded by water. 
About half a metre of the difficultly fusible German glass 
known as combustion-tubing is sealed at one end after the 
manner of a test-tube (Fig. 78) ; a mixture of bicarbonate of 
sodium and dry chalk is then dropped into the tube to the 
height of 2 or 3 centimetres, and, next, several small frag- 590 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
ments of quicklime so as to occupy another centimetre : a 
mixture of about a gramme of pure calomel or corrosive sub- 
limate with enough powdered quicklime to occupy TO or 12 
centimetres of the tube is added; then the lime-rinsings of the 
mixing-mortar, a layer of a few centimetres of powdered quick- 
lime, and finally a plug of asbestos (a fibrous mineral unaf- 
Figs. 78, 79, 80. 
fected by beat), The whole powder should occupy two-thirds 
of the length of the tube. The part of the tube just above 
the asbestos is now softened in the blowpipe-flame and drawn 
out about a decimetre to the diameter of a narrow quill; it 
is again drawn out to the same extent at a point about two 
or three centimetres nearer the mouth, and any excess of tub- 
ing cut off. The bulb thus formed may be enlarged by soften- 
ing and blowing. The tube is next softened at a point close 
to but anterior to the asbestos, and bent to form an obtuse 
angle ; the tube is then softened close to the bulb and slightly 
bent, so that the bulb may be parallel with the large tube ; then 
softened on the other side of the bulb, and the terminal tube 
bent to an obtuse angle, so that, the tube being held in a hori- 
zontal position, the bulb may be sunk in water and the terminal 
tube point upward (Fig. 80). The long tube is now laid in 
the gas-furnace found in most laboratories (Fig. 81), a basin 
so placed that the bulb of the apparatus may be cooled by 
being surrounded by water, the part of the tube occupied by 
asbestos heated to redness, and the flame slowly lengthened 
until the whole tube is red hot. Under the circumstances just 
described the mercurial compound volatilizes, is decomposed by 
the lime, and its acidulous radical fixed, the mercury carried to 
and condensed in the bulb, the carbonic acid gas evolved from 
the bicarbonate of sodium and chalk washing out the last por- 
tions of mercury vapor from the tube. When the distillation 
is considered to be complete, the dish of water is removed, the 
bulb dried, and then detached by help of a file at a point 
beyond any sublimate of mercury. The bulb is lastly weighed, 
the mercury shaken or dissolved out, and the tube again dried 
and weighed. ESTIMATION OF LEAD. 
Process 2.—The process by which mercury is separated in 
the form of calomel consists in adding hydrochloric and phos- 
phorous acids (vide p. 348) to an aqueous or even acid solu- 
Fig. 81. 
tion of a weighed quantity of the mercurial compound, setting 
the mixture aside for twelve hours, collecting the precipitate 
on a tared filter, washing, drying at 100° C., and weighing 
(Rose). The experiment may be tried on half a gramme to a 
gramme of corrosive sublimate. 
Process 3.—Two or three decigrammes of corrosive subli- 
mate are dissolved in water, the solution acidulated with hy- 
drochloric acid, excess of sulphuretted hydrogen passed through 
it, the precipitate collected on a tared filter, washed with cold 
water, dried at 100° C., and weighed. 
Distillation of Mercury for Quantitative Purposes. 
Proportional Weights of Equivalent Quantities of Mercury and 
its Salts. 
Metal ...... Hg 199.7 
Mercurous chloride . . . IlgCl 235.1 
Mercuric chloride . . . HgCl2 270.5 
Mercuric sulphide . . . HgS 231.7 
LEAD. 
Lead is generally estimated either as (1) oxide, (2) sulphate, 
(3) chromate, or (4) metal. 
Process 1.—Weigh out 1 or 2 grammes of pure acetate of 
lead in a covered crucible previously tared, and heat slowly 
until no more vapors are evolved. Remove the lid, stir down 
the carbonaceous mass with a clean iron wire, and keep the 
crucible in the flame so long as any carbon remains unconsumed. 
Introduce some fragments of fused nitrate of ammonium, and 
again ignite until no metallic lead remains and all excess of GRAVIMETRIC QUANTITATIVE ANALYSIS. 
the nitrate has been decomposed. Cool and weigh the result- 
ing oxide (PbO). 
Process 2.—Dissolve 0.4 or 0.5 of a gramme of acetate of 
lead in a small quantity of water, drop in diluted sulphuric 
acid, add to the mixture twice its bulk of methylated spirit of 
wine, and set aside. Decant the supernatant liquid, collect the 
sulphate on a filter, wash with spirit, dry, transfer to a porce- 
lain crucible, removing as much of the sulphate as possible 
from the paper, incinerate on the crucible-lid (not in the plati- 
num coil, for the particles of reduced lead would unite with the 
platinum by fusion), ignite, cool, and weigh. 
Process 3.—About half a gramme of acetate of lead is dis- 
solved in 200 or 300 c.c. of water, acetic acid added, and then 
solution of red chromate of potassium. Collect the precipitate 
on a tared filter, wash, dry at 100° C., and weigh. 
Process ]/..—In certain cases, notably in that of commercial 
white lead, the lead may be estimated in the metallic state by 
means of cyanide of potassium. The lead paint (about 20 
grammes) is weighed and carefully incinerated. The residue, 
a mixture of metallic lead and oxide of lead, is then mixed 
with several times its bulk of cyanide of potassium and the 
whole heated to fusion. With careful manipulation the lead 
collects in one globule, which, after cooling, may readily be 
separated from the mixed cyanide and cyanate and weighed. 
White lead, commercially pure, should contain 74 per cent, of 
lead. 
Molecular Weight of Salts of Lead. 
Metal . . . . Pb 206.5 
Acetate .... Pb2C2HA>2H20 . 378.5 
Oxide .... PbO 222.5 
Sulphate . . . PbS04 302.5 
Chromate . . . PbCrO* .... 322.9 
SILVER. 
Compounds of silver which are readily decomposed by heat 
are estimated in the form of (1) metal, others usually as (2) 
chloride (AgCl), but sometimes as (3) cyanide (AgNC). 
Process 1.—Heat about a gramme of oxide of silver (Ag-jO) 
in a tared crucible, cool, and weigh. 231.4 of oxide yield 215.4 
of metal. “ 29 grains heated to redness yield 27 grains of 
metallic silver.”—Brit. Pliarm. 
Process 2.—Dissolve 0.4 or 0.5 grm. of pure dry crystals of 
nitrate of silver in water, acidulate with two or three drops of 
nitric acid, slowly add hydrochloric acid, stirring rapidly, until 599 
ESTIMATION OF SILVER. 
no more precipitate falls. Pour off the supernatant liquid 
through a filter, wash the chloride of silver once or twice with 
hot water, transfer to the filter, complete the washing, and dry. 
After removing as much as possible of the precipitate from the 
paper to the crucible, burn the filter, letting its ash fall on the 
inverted lid of the crucible, moisten with a drop of nitric acid, 
warm, add a drop of hydrochloric acid, evaporate to dryness, 
replace the lid on the crucible, unite the whole until the edges 
of the mass of chloride begin to fuse; cool and weigh. 169.7 
of nitrate yield 143.1 of chloride. According to the United 
States Pharmacopoeia, 10 parts of nitrate should thus yield 
8.4 of chloride, while 20 parts of “ moulded nitrate of silver ” 
should yield 16 of chloride, and the filtrate from the chloride 
evaporated to dryness should leave no residue, indicating ab- 
sence of nitrates of potassium or sodium and other similar 
adulterants. 20 parts of “ diluted nitrate of silver ” should 
yield 8.4 of chloride; 10 parts of “oxide of silver” should 
yield 12.36 of chloride. 
Process 3.—Cyanide of silver may he collected on a tared 
filler and dried at 100° C. 169.7 of nitrate yield 133.7 of 
cyanide. 
Silver and its salts may be volumetrically estimated by a 
standard solution of chloride of sodium. 
Cupellation.—The amount of silver in an alloy may be also deter- 
mined by a dry method. The metal is folded in a piece of thin sheet 
lead, placed on a cupel (cupella, little cup, made of compressed bone- 
earth), and heated in a furnace, the cupel being protected from the 
direct action of flame by a muff-shaped or, rather, oven-shaped, case 
termed a muffle. The metals melt, the baser become oxidized, the 
oxide of lead fusing and dissolving the other oxides; the fluid oxides 
sire absorbed by the porous cupel, a button of pure silver remaining. 
An alloy supposed to contain 95 per cent, of silver requires about 
three times its weight of lead for successful cupellation ; if 92£ per 
cent. (English silver coin), between five and six times its weight of 
lead is necessary. 
1035. Explain the gravimetric process by which the strength of 
the official solutions of ferric chloride, nitrate, and sulphate is deter- 
mined. 
1036. Mention the various amounts of ferrous and ferric salts 
equivalent to 100 parts of metal. 
1037. State the precautions necessary to he observed in estimating 
arsenicum or antimony in the form of sulphide. 
1038. In what form are the official compounds of bismuth weighed 
for quantitative purposes? 
QUESTIONS AND EXERCISES. 600 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
1039. Give an outline of the process by which mercury may be 
isolated from its official preparations and weighed in the metallic 
condition. 
1040. Describe three methods for the quantitative analysis of salts 
of lead, and the weights of the respective precipitates, supposing 
0.56 of crystallized acetate to have been operated on in each case. 
1041. Describe the process by which silver is estimated in the 
forms of metal, chloride, and cyanide. 
1042. What proportions of nitrate of silver are indicated, respec- 
tively, by 15 of metal, 9.8 of chloride, and 8.1 of cyanide? 
1043. Describe cupellation. 
GRAVIMETRIC ESTIMATION OF THE ACIDULOUS 
RADICALS OF SALTS. 
CHLORIDES. 
Free chlorine (chlorine-water) and compounds which by ac- 
tion of acids yield free chlorine (Chlorinated Lime, Chlori- 
nated Soda, and their official solutions) are estimated volumet- 
rically by a standard solution of hyposulphite of sodium (vide 
p. 578). The amount of combined chlorine in pure chlorides 
(HC1, NaCl) may also be determined by volumetric analysis 
with a standard solution of nitrate of silver (p. 567). 
Combined chlorine is gravimetrically estimated in the form 
of chloride of silver, the operation being identical with that 
just described for silver salts (p. 599). 58.4 parts of pure, 
colorless, crystallized chloride of sodium (rock-salt) yield 
143.1 of chloride of silver. 
Free iodine is estimated volumetrically by solutions of hypo- 
sulphite of sodium (vide p. 579). 
Combined iodine is determined gravimetrically in the form 
of iodide of silver, the operations being conducted as with chlo- 
ride of silver. Iodide of potassium may be used for an experi- 
mental determination : KI = 165.1 should yield Agl = 234.3. 
Of iodide of cadmium (Cadmii lodidum, B. P.) it is stated 
that “ 10 grains dissolved in water, and nitrate of silver added 
in excess, give a precipitate which, when washed with water 
and afterward with half an ounce of solution of ammonia, 
and dried, weighs 12.5 grains.” 
In presence of chlorides and bromides the iodine in iodides 
may be precipitated and weighed as iodide of palladium. 
Moisture in iodine is estimated by loss on exposing a weighed 
quantity of iodine in a capsule over a dish of sulphuric acid 
IODIDES. ESTIMATION OF NITRATES. 
601 
under a small bell-jar, or by adding to a weighed sample five 
or six times as much mercury or twice as much zinc, and a 
little water, drying and weighing. The product is the amount 
of metal employed plus that of the dry iodine in the sample. 
BROMIDES. 
Free bromine may be estimated by shaking with excess of 
solution of iodide of potassium, and then determining the 
equivalent quantity of liberated iodine by a standard solution 
of hyposulphite of sodium (p. 579). 
The bromine in bromides may be precipitated and weighed 
as bromide of silver, the manipulations being the same as those 
for chloride of silver: 0.2 to 0.3 of pure bromide of potassium 
may be used for an experimental analysis. 
Ammonii Bromidum, U. S. P. : “1 gm. of the powdered and 
dry salt, when completely precipitated by nitrate of silver, 
yields, if perfectly pure, 1.917 gm. of dry bromide of silver.” 
Cal' ii Bromidum, U. S. P.: “1 gm of the dry salt, when com- 
pletely precipitated by nitrate of silver, yields, if perfectly 
pure, 1.878 gm. of dry bromide of silver.” 
The hydrogen cyanide (hydrocyanic acid) is usually esti- 
mated volumetrically (vide p. 567). 
From all soluble cyanides cyanogen may be precipitated by 
nitrate of silver after acidulating with nitric acid, the cyanide 
of silver collected on a tared filter, dried at 100° C., and 
weighed. 
Of the official Diluted Hydrocyanic Acid it is stated that 
100 grains (or 110 minims), precipitated by solution of nitrate 
of silver, yield 10 grains of dry cyanide of silver. 
CYANIDES. 
Cyanide of Silver. 
In 1 molec. wt. In 100 parts. 
Silver . . . Ag . . 107.7 . . 80.55 
Cyanogen . CN . . 26.00 . . 19.45 
133.7 100.00 
NITRATES. 
Nitrates cannot be estimated by direct gravimetric analysis, 
none of the basylous radicals yielding a definite nitrate insolu- 602 
GRAVIMETEIC QUANTITATIVE ANALYSIS. 
ble in water. With some difficulty they may be determined 
by indirect volumetric methods. 
Process.—The following (Thorpe’s) method depends upon 
the fact (Gladstone and Tribe) that when zinc upon which 
copper is deposited in a spongy form is boiled with water 
hydrogen is evolved. Thorpe found that in a solution con- 
taining nitrates the nascent hydrogen converts the whole of the 
nitrogen of the nitrates into ammonia, which may be collected 
and estimated. (The oxygen of the nitrate is simultaneously 
converted into water, the nitrate-metal into hydrate, and the 
zinc into hydrate of zinc. The power of the copper-zinc couple 
is considered to depend largely on the hydrogen absorbed by 
the finely-divided metal.) 
An apparatus such as shown in Fig. 82 should be con- 
structed. A flask (about 
100 c.c.) is fitted with an 
India-rubber cork, per- 
forated for a delivery-tube, 
which should be of strong 
glass tubing of about quar- 
ter-inch bore, and for a 
stoppered funnel, which 
should have about half the 
capacity of the flask. The 
whole is supported by a 
clamp or on wire-gauze. 
The outer jar shown in the 
figure should have a capa- 
city of 2 or 3 litres, and the 
inner receiving-jar should 
be capable of holding 200 
c.c. The latter is fitted 
with an India-rubber cork, perforated for the delivery-tube, 
and for another tube containing fragments of glass. 
A few strips of clean zinc are boiled in a beaker with a 2-per 
cent, solution of sulphate of copper, the operation being re- 
•peated with a fresh portion of solution six consecutive times. 
A thick coating of finely-divided copper is deposited. The 
pieces of metal are well washed and introduced into the flask, 
which is then half filled with pure water. To avoid transfer- 
ence, the flask itself may be used instead of the beaker. The 
funnel also is filled with pure water. Into the inner receiver 
is put a little pure water very slightly acidulated with hydro- 
chloric acid, and the glass fragments are also moistened with 
the dilute acid (to prevent possible loss of ammonia). Water 
Fig. 82. 
Estimation of Nitrates. ESTIMATION OF NITRATES. 
603 
is now placed around the inner receiver in the outer jar, and, 
the connections being sound, heat is applied with the view of 
freeing the apparatus itself from any trace of ammonia. When 
the contents of the flask are evaporated nearly to dryness, pure 
water is admitted from the funnel until the flask is again about 
half full (the funnel should be filled again at once), and the 
distillation carried on as before. This must be repeated until 
no further trace of ammonia is evolved, when the apparatus is 
ready for use. On each occasion that the apparatus is used it 
must be freed from ammonia in this way. A suitable quantity 
of the substance to be estimated is now introduced (in the case 
of potable waters the prepared solid residue from 100 c.c.,.with 
an added fragment of recently ignited lime, the size of a hemp- 
seed, to promote the evolution of the ammonia), and water 
added, if necessary, until the flask is half full. Heat is now 
applied, and the operation conducted in the manner already 
described until ammonia ceases to come over—a point which 
always occurs in the case of water-residues when the flask has 
been refilled twice and the distillate is about 100 c.c. The 
warm water from the upper part of the cooling-jar may be re- 
moved by a siphon or otherwise, cold water being introduced 
from time to time. 
The ammonia being all evolved, disconnect the flask and re- 
ceiver simultaneously (unless washing-bottle tubes are fitted), 
and treat the contents of the latter by the Nessler method, 
described on page 558. Urea yields but traces of ammonia 
by this process, and neither the sulphates nor chlorides of the 
alkali-metals affect the result. The method is only applicable 
to highly dilute solutions of nitrates, for with stronger solu- 
tions oxides of nitrogen are formed and escape. 
Another process (Pelouze’s improved by Fresenius) consists 
in adding the nitrate to an acid solution of a ferrous salt of 
known strength, and, when reaction is complete, estimating the 
amount of ferrous salt unattacked by volumetric solution of red 
chromate or of permanganate. Three molecular weights of con- 
verted ferrous salt indicate one molecular weight of nitric acid. 
Regeneration of nitric or nitrous acids by aerial oxidation of 
the nitric oxide evolved is prevented either by a current of 
carbonic acid gas or by using a closed flask in which is a Bun- 
sen valve (i. e. a short attached piece of India-rubber tubing 
closed at the free extremity and having a sharp longitudinal 
slit in it a third of an inch long—a slit by which gases can 
escape, but cannot re-enter). 
Potassii Nitras, U. S. P. : “ If 1 gm. of the dried salt be 
moistened with 1 gm. of concentrated sulphuric acid, and the 604 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
mixture be kept at a red heat until it ceases to lose weight, the 
residue should weigh 0.86 gm.” 
SULPHIDES. 
Process 1.—Soluble sulphides (H2S, NaHS, e. g.~) may be 
determined volumetrically by adding to the aqueous liquid a 
measured excess of an alkaline solution of arsenic of known 
strength, neutralizing by hydrochloric acid, diluting to any 
given volume, filtering off the sulphide of arsenicum precipi- 
tated, taking a portion of the filtrate equal to half or a third 
of the original volume, and, after neutralizing by acid carbo- 
nate of sodium, estimating the residual arsenic by the standard 
iodine solution (vide p. 572). The process may be tried on a 
measured volume of sulphuretted hydrogen (the weight of 
which is easily calculated: 1 litre of hydrogen = 0.0896 
gramme) absorbed by a strong solution of soda or potash. 
Process 2.—Sulphur and sulphides may also be quantita- 
tively analyzed by oxidizing to sulphuric acid and precipitating 
in the form of sulphate of barium. A couple of decigrammes 
of a pure metallic sulphide may be decomposed by careful 
deflagration with a mixture of chlorate of potassium and car- 
bonate of sodium, the product dissolved in water, acidulated 
with hydrochloric acid, solution of chloride of barium added, 
and the precipitated sulphate of barium purified and collected 
as described in connection with the estimation of barium 
(p. 587). Many sulphides may be oxidized in a flask by 
chlorate of potassium and hydrochloric acid, and then precip- 
itated by chloride of barium. Experimental determinations 
may also be made on a weighed fragment of sulphur, about 0.1 
grm., cautiously fused with a solid caustic alkali, and the product 
oxidized while hot by the slow addition of powdered nitrate or 
chlorate of potassium, or, when cold, by treatment with chlorate 
of potassium and hydrochloric acid, and subsequent precipita- 
tion by chloride of barium. 
Note.—Fusions performed by help of a gas-lainp must be carefully 
conducted, for any alkali that may creep over the side of a crucible 
will certainly absorb sulphurous acid from the products of combus- 
tion of the gas, and error result. 
Process 3.—Soluble sulphides may also be treated with ex- 
cess of an alkaline arsenite, arsenous sulphide be then precip- 
itated by the addition of hydrochloric acid, and the precip- 
itate collected and weighed with the usual precautions (vide 
p. 593). ESTIMATION OF SULPHATES. 
605 
Weights of Equivalent Quantities of Sulphur and its 
Compounds. 
Sulphur 
. S . . . . 
... 32 
Sulphuretted hydrogen 
. H„S . . . 
... 34 
Sulphate of barium . 
. BaS04 . . 
. . . 232.8 
Arsenious sulphide . 
. (As2S3) -s- 3 
... 82 
Bisulphide of iron . 
. (FeSa) 2 . 
... 60 
Sulphide of lead . 
. PbS . . . 
. . . 238.5 
SULPHITES. 
Sulphites are usually estimated volumetrically by a standard 
solution of iodine (vide p. 572). Sulphites insoluble in water 
are diffused in that menstruum, hydrochloric acid added, and 
the iodine solution then dropped in. 
If necessary, sulphites may be estimated gravimetrically by 
oxidation and precipitation in the form of sulphate of barium. 
SULPHATES. 
These salts are always precipitated and weighed as sulphate 
of barium, the manipulations being identical with those per- 
formed in the determination of barium by means of sulphates 
(vide p. 587). The purity of Sulphate of Sodium (Sodii Sul- 
phas, U. S. P.), and the presence of not more than a given 
amount of sulphuric acid in vinegar (Acetum, B. P.), are 
directed, in the British Pharmacopoeia, to he ascertained by 
this process. Ten grains of sulphate of sodium yield 7.23 of 
sulphate of barium. Five ounces of vinegar should yield not 
more than about one-third of a gramme of sulphate of barium. 
The amount of free sulphuric acid or hydrochloric acid in 
vinegar, lemon-juice, lime-juice, etc. may also be ascertained 
volumetrically by adding a known quantity of standard solu- 
tion of soda, evaporating to dryness, incinerating, dissolving 
in water, and, by standard acid, estimating the quantity of soda 
still remaining free. The soda lost indicates the amount'of 
free mineral acid (Hehner). Thresh estimates the chlorine in 
a sample of vinegar, adds a known additional amount of chlo- 
rine, preferably in the form of chloride of barium, evaporates, 
ignites; treats with water, adds bicarbonate of sodium to 
move excess of barium, filters, and again estimates the chlorine, 
A loss of 70.8 of chlorine (Cl2) indicates 98 of free sulphuric 
acid (H,S04). The method of estimating free sulphuric, nitric, 
or hydrochloric acid proposed by Spence and Esilman is 
founded on their power of decolorizing a standard solution of 
ferric acetate. GRAVIMETRIC QUANTITATIVE ANALYSIS. 
Proportional Weights of Equivalent Quantities of Sulphates. 
The sulphuric radical . . . S04 96 
Sulphuric acid H2S04 98 
Sulphate of barium . . . BaS04 232.8 
CARBONATES. 
Carbonates are usually estimated by the loss in weight they 
undergo on the addition of a strong acid. 
Process 1.—A small light flask is selected—of such a size 
that it can be conveniently weighed in a delicate balance. Two 
narrow glass tubes are fitted to the flask 
by a cork ; the one straight, extending 
from about two or three centimetres above 
the cork to the bottom of the flask : the 
other cut off close to the cork on the in- 
side and curved outward, so as to carry 
a thin drying-tube horizontally above the 
flask. (See Fig. 83.) The drying-tube 
is nearly filled with small pieces of chlo- 
ride of calcium, a plug of cotton-wrool 
preventing escape of any fragments at 
either end, and is attached by a pierced 
cord to the free extremity of the curved 
tube of the flask. A weighed quantity of any pure soluble 
carbonate is placed in the flask, a little water added, a minia- 
ture test-tube containing sulphuric acid lowered into the flask 
by a thread and supported so that the acid may not flow out. 
the cork inserted, the outer end of the piece of the straight 
glass tube closed by a fragment of cork or wax, and the whole 
weighed. The apparatus is then inclined so that the oil of 
vitriol and carbonate may slowly react; carbonic acid gas is 
evolved and escapes through the horizontal tube, any moisture 
being retained by the chloride of calcium. When efferves- 
cence has ceased, the gas still remaining in the vessel is sucked 
out; this is accomplished by adapting a piece of India-rubber 
tubing to the end of the drying-tube, removing the small plug 
from the straight tube, and aspirating slowly with the mouth 
for a few minutes. If the heat produced by the action of oil. 
of vitriol and solution is considered insufficient to expel all the 
carbonic acid from the liquid, the plug is again inserted in the 
tube and the contents of the flask gently boiled for some seconds. 
When the apparatus is nearly cold more air is again drawn 
through it, and the whole finally weighed. The loss is due to 
carbonic acid gas (C02), from the weight of which that of any 
Fig. 83. 
Estimation of Carbonates. ESTIMATION OF OXALATES. 
607 
carbonate is ascertained by calculation. Carbonates insoluble 
in water may be attacked by hydrochloric instead of sulphuric 
acid ; granulated mixtures of carbonates and powdered tartaric 
or citric acid by enclosing the preparation in the inner tube 
and placing water in the .flask, or vice versa. The apparatus 
also may be modified in many ways to suit the requirements, 
convenience, or practice of the operator. 
Process 2.—Carbonates from which carbonic acid gas is 
evolved by heat may be estimated by the loss they experience 
on ignition. 
Process 3.—Free carbonic acid gas may be absorbed by a 
solid stick of potash or a strong alkaline solution, the loss in 
volume of the gas or mixture of gases indicating the amount 
originally present. 
Weights of Equivalent Quantities of Carbonic Acid Gas and 
certain Carbonates. 
Carbonic acid gas C02 44 
Carbonic acid H2C03 .... 62 
Anhydrous carbonate of sodium . Na2C03 .... 106 
Crystalline carbonate of sodium . Na2CO3,10H2O. . 286 
Anhydrous carbonate of potassium . K2C03 .... 138 
Crystalline carbonate of potassium. K2C03-|-16%aq.l64. 285 
Carbonate of calcium CaC03 . . . . 100 
OXALATES. 
P, •ocess 1.—The oxalic radical is usually precipitated in the 
form of oxalate of calcium and weighed as carbonate, the 
manipulations being identical with those observed in the esti- 
mation of calcium (vide p. 588). The experiment may be 
performed on 0.3 or 0.4 grm. of pure crystallized oxalic acid, 
126 parts of which should yield 100 of carbonate of calcium. 
Process 2.—Oxalates may also be determined by conversion 
of their acidulous radical into carbonic acid gas, and observa- 
tion of the weight of the latter. The oxalate, water, and 
excess of black oxide of manganese are placed in the carbonic 
acid apparatus (page 606), a tube containing oil of vitriol low- 
ered into the flask, the whole weighed, and the operation com- 
pleted as for carbonate. From the following equation it will 
be seen that every 88 parts of carbonic acid gas evolved indi- 
cate the presence of 126 parts of crystallized oxalic acid or an 
equivalent quantity of other oxalate :— 
Na,CA + MnO* + 2H2S04 = MnS04 + Na2S04 + 2H20 
+ 2CO., 608 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
The black oxide of manganese used in this experiment must 
be free from carbonates. The amount of materials employed 
is regulated by the size of the vessels. 
Process 1.— From phosphates dissolved in water the phos- 
phoric radical may be precipitated and weighed in the form of 
pyrophosphate of magnesium, the details of manipulation being 
similar to those observed in estimating magnesium (vide p. 
589). Half a gramme or rather more of pure dry crystallized 
phosphate of sodium may be employed in experimental deter- 
minations. The official phosphate of ammonium (Ammonii 
Phosphas, U. S. P.) is quantitatively analyzed by this method. 
“ 2 gm. of the salt, dissolved in water and precipitated with 
test-mixture of magnesium, yields a crystalline precipitate, 
which, when washed with diluted water of ammonia, dried, 
and ignited, should weigh 1.68 gm.” Half a gramme or less 
is a more convenient quantity if the operations be conducted 
with care. Solution of ammonia-sulphate of magnesium (U. S. 
P.) is prepared by dissolving 1 part of sulphate of magne- 
sium, 2 of chloride of ammonium, and 4 of solution of ammo- 
nia (10-per cent. NH3) in 8 of distilled water; such a solution 
is of considerable use if several phosphoric determinations are 
about to be made. 
Process 2.—Free phosphoric acid is most readily determined 
as phosphate of lead (Pb32P04). Of the official solution of 
phosphoric acid it is stated that “ on pouring 5 gm. of phos- 
phoric acid upon 10 gm. of oxide of lead free from carbonate 
of lead and from moisture, evaporating and igniting, a residue 
will be obtained which should weigh 11.81 gm.” In the case 
of the diluted acid, 5 gm. with 5 of lead oxide should yield 
5.36. The oxide of lead must be quite pure : it should be 
prepared by digesting red lead in warm dilute nitric acid, 
washing, drying, and heating a resulting puce-colored plumbic 
oxide in a covered porcelain crucible. The increase in weight 
obtained on evaporating a given amount of solution of phos- 
phoric acid with a known weight of perfectly pure oxide of 
lead (PbO) may be regarded as entirely due to phosphoric an- 
hydride (P.A), 
PHOSPHATES. 
the actual reaction being 
3PbO + P205 = Pb32P04, 
3PbO + 2H3P04 = Pb32P04 + 3IP0. 
From these equations and the table of atomic weights (vide ESTIMATION OF PHOSPHATES. 
Appendix) the percentage of phosphoric acid (H3P04) in any 
specimen of its solution may be easily calculated. 
Process 3.— The strength of pure solution of phosphoric 
arid may be ascertained by specific gravity and reference to 
Tables. 
Process f—Bone-earth, “ superphosphate,the Calais Plios- 
phas of pharmacy, and other forms of phosphate of calcium 
known to be tolerably free from iron or aluminium, may be 
estimated by treating about half a gramme with hydrochloric 
acid somewhat diluted, filtering if necessary, warming, precip- 
itating with excess of ammonia, collecting the precipitate 
(Ca32P04), washing, drying, igniting, and weighing. “ Calcis 
Phosphasf if pure, will in this process lose no weight. 
Process 5.—Insoluble phosphates in ashes, manures, etc. are 
treated as follows: A weighed quantity of the material (1.0 
to 10.0 grm.) is digested in hydrochloric acid diluted with three 
or four times its bulk of water; filtered (insoluble matter and 
filter being thoroughly exhausted by water) ; ammonia added 
to the filtrate and washings until, after stirring, a faint cloudy 
precipitate is perceptible; solution of oxalic acid dropped in 
until, after agitation for a few minutes, the opalescence is de- 
stroyed ; oxalate of ammonia next added, the whole wrarmed, 
oxalate of calcium removed by filtration, and the filtrate con- 
centrated if very dilute; the liquid treated with citric acid in 
such quantity that ammonia when added in excess gives a clear 
lemon-yellow solution (Warington), magnesian mixture poured 
in (as in Process 1), and the precipitate of ammonio-magnesian 
phosphate collected, washed, dried, and weighed, as already de- 
scribed in connection with the estimation of magnesium. 
Relative Weights of Equivalent Quantities of Phosphoric 
Compounds. 
Phosphoric acid H3P04 98 
Pyrophosphate of magnesium . (MgaP207 = 222)-5-2= 111 
Phosphate of lead .... (Pb32P04 = 811) -h2= 405.25 
Phosphoric anhydride . . . (P205 = 142) -5-2= 71 
Phosphate of calcium . . . (Ca:,2P04= 310)-5-2= 155 
Superphosphate of calcium . (CaFI42P04=234-5-2= 117 
1044. What quantity of pure rock-salt is equivalent to 4.2 parts 
of chloride of silver? Ann. 1.714. 
1045. State the percentage of real iodide of potassium contained 
in a sample of which 8 parts yield 10.9 of iodide of silver. Ans. 96.3. 
1046. What is the strength of a solution of hydrocyanic acid 10 
QUESTIONS AND EXERCISES. 610 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
parts of which, by weight, yield .9 of cyanide of silver. Ans. 1.87 
per cent. 
1047. How are nitrates quantitatively estimated? 
1848. By what processes may the strength of sulphides be deter- 
mined ? 
1049. How much real sulphate of sodium is contained in a speci- 
men 10 parts of which yield 14.2 of sulphate of barium. Ans. 86.61 
per cent. 
1050. Give details of the operations performed in the quantitative 
analysis of carbonates. 
1051. What amount of carbonic acid gas should be obtained from 
10 parts of acid carbonate (or bicarbonate) of potassium? Ans. 4.4 
parts. 
1052. To what operation and what proportion of materials does 
the following equation refer?— 
Na2C204 + Mn02 -f 2II2S04 == MnS04 + Na2S04 + 2II20 + 2C02. 
1053. Explain the lead process for the estimation of phosphoric 
acid in the official solution. 
1054. State the amount of superphosphate of calcium equivalent 
to 7.6 parts of pyrophosphate of magnesium. Ans. 8.01. 
SILICATES. 
Silica (Si02) may be separated from alkaline silicates, or 
from silicates decomposable by hydrochloric acid, by digesting 
the substance in hydrochloric acid at a temperature of 70° or 
80° C. until completely disintegrated, evaporating to dryness, 
heating in an air-bath, again moistening with acid, diluting 
with hot water, filtering, washing, drying, igniting, and weigh- 
ing. 
ESTIMATION OF WATER. 
Water and other matters readily volatilized are most usually 
estimated by the loss in weight which a substance undergoes 
on being heated to a proper temperature. Thus, in the British 
Pharmacopoeia crystalline gallic acid (HiC7H;i05,H20) is stated 
to lose 9.5 per cent, of its weight at a temperature of 100° C., 
oxalate of cerium (CeC204,3H20) 52 per cent, on incineration, 
carbonate of potassium about 16 per cent, on exposure to a red 
heat, sulphate of quinine (2C20H24N2O2,H2SO4,7H2O) 14,4 per 
cent, at 100° C., arseniate of sodium (Na2HAs04,7H20) 40.38 
per cent, at 149° C., carbonate of sodium (Na2CO3,10H2O) 60.3 
per cent., phosphate of sodium (Na2HP04,12H20) 63 per cent., 
and sulphate of sodium (Na2SO4,10H2O) 55.9 per cent, at a 
low red heat; oxide of bismuth heated to incipient redness 
should not diminish in weight. CARBON, HYDROGEN, OXYGEN, NITROGEN. 
611 
Process.—One or two grammes of substance is sufficient in 
experiments on desiccation, the material being placed in a 
watch-glass, covered or uncovered porcelain crucible, or other 
vessel, according to the temperature to which it is to be ex- 
posed. Rapid desiccation at an exact temperature may be 
effected by introducing the substance into a tube having some- 
what the shape of the letter U, sinking the lower part of the 
tube into a liquid kept at a definite temperature by aid of a 
thermometer, and drawing or forcing a current of dry air 
slowly through the apparatus. Substances liable to oxidation 
may be desiccated in a current of dried carbonic acid gas. The 
weights of the U-tube before and after the introduction of the 
salt, and after desiccation, give the amount of water sought. 
In all cases the material must be heated until it ceases to lose 
weight. Occasionally it is desirable to estimate water directly 
by conveying its vapor in a current of air through a weighed 
tube containing chloride of calcium and reweighing the tube at 
the close of the operation ; the increase shows the amount of 
water. 
Note.—Highly dried substances rapidly absorb moisture from the 
air; they must therefore be weighed quickly, enclosed, if possible, 
in tubes (p. 583), a pair of clamped watch-glasses, or a crucible 
having a tightly fitting lid. 
CARBON, HYDROGEN, OXYGEN, NITROGEN. 
The quantitative analysis of animal and vegetable substances is 
either proximate or ultimate. Proximate quantitative analysis in- 
cludes the estimation of water, oil, albumen, starch, cellulose, gum, 
resins, alkaloids, acids, glucosides, ash. It requires the application 
of much theoretical knowledge and manipulative skill, and cannot 
well be studied except under the guidance of a tutor. One of the 
best of the published works on the subject is by Rochleder, a transr 
lation of whose monograph will be found in the Pharmaceutical 
Journal, vol. i. 2d ser. pp. 562, 610; vol. ii. 2d ser. pp. 24, 129, 160, 
215, 274, 420, 478. Another is a small book by Professor A. B. 
Prescott, Outlines of Proximate Organic Analysis, Van Nostrand, 
New York. 
Ultimate quantitative organic analysis can only be successfully 
accomplished with the appliances of a well-appointed laboratory—a 
good balance, a gas-furnace giving a smokeless flame (7 or 8 centi- 
metres wide and 70 or 80 centimetres long), special forms of glass 
apparatus, etc. The theory of the operation is simple: A weighed 
quantity of a substance is burnt to carbonic acid gas (CO, = 44) and 
water (1I20 = 18), and these products collected and weighed; 12 
parts in every 44 of carbonic acid gas (=T3T) are carbon, 2 in every 
18 of water (= ,j) are hydrogen ; nitrogen if present escapes as gas. 
If nitrogen be a constituent, more of the substance is strongly heated 612 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
with a mixture of the hydrates of sodium and calcium ; these bodies 
then split up into oxides, oxygen, and hydrogen; the oxygen burns 
the carbon of the substance to carbonic acid gas, its hydrogen and 
nitrogen appearing as water and ammonia respectively ; the car- 
bonic acid and water are disregarded, the ammonia collected and 
weighed in the form of a double chloride of platinum and ammonium 
(PtCl42NII4Cl = 442.8), of which 28 parts in every 442.8 (=xV) are 
nitrogen. The difference between the sum of the weights of hydro- 
gen and carbon, and the weight of substance taken, is the proportion 
of oxygen in the body, supposing nitrogen to be absent. If nitrogen 
is present, the difference between the sum of the percentage of car- 
bon, hydrogen, and nitrogen, and 100, is the percentage of oxygen. 
Shortly, carbon is estimated in the form of carbonic acid gas, hydro- 
gen as water, nitrogen as ammonia, and oxygen by loss. 
The following is the outline of the necessary manipulation:— 
The source of the oxygen for the combustion of carbon and 
hydrogen is black oxide of copper in coarse powder. 200 or 
300 grammes of this material are heated in a crucible to low 
redness for a short time to expel every trace of moisture ; then 
transferred to store-tubes (Fig. 84) resembling test-tubes, half 
Fig. 84. 
a metre long, and having a slightly narrowed mouth, the tube 
being held in a cloth to protect the hand while the hot oxide 
is being directly introduced into the mouth of the tube by a 
scooping motion. As soon as the well-corked tube is cool, the 
oxide is poured, portion by portion, into a similar tube (the 
combustion-tube), but somewhat longer, drawn out to a quill 
(bent upward nearly to a right angle) at one end and not con- 
stricted at the mouth. Two such tubes are readily made by 
softening in the blowpipe-flame two or three centimetres of the 
central part of a tube about a metre long, and drawing the 
halves of the tube apart, as shown in the following engraving 
(Fig. 85). The tubes are separated by melting the glass in the 
middle of the quilled portion. A few decigrammes of fused 
chloi’ate of potassium should first be dropped into the tube. 
After ten or fifteen centimetres of oxide have been poured in, 
about a decigramme of the substance to be analyzed is dropped 
down the tube, then a few grammes of oxide, then another 
decigramme of substance, then more oxide, until three or four 
decigrammes of the body under examination have been added. 
The fifteen or twenty centimetres of alternate layers are next 
thoroughly mixed by a long copper wire having a short helix; 
more oxide is introduced, the wire cleansed by twisting the CARBON, HYDROGEN, OXYGEN, NITROGEN. 
613 
helix about in the pure oxide, and a plug of dry asbestos 
finally placed on the top of the oxide at about five centimetres 
from the mouth of the tube ; the tube is then securely corked 
and set aside. The substance operated on may be pure white 
Fig. 85. 
sugar, powdered and dried; the tube in which it is contained 
is weighed before and after the removal of a portion for com- 
bustion ; the loss is the quantity employed in the experiment. 
The combustion-furnace may be such as shown on page 597. 
If the furnace is very powerful or the combustion-tube not of 
the hardest glass, the tube should be enclosed in wire-gauze the 
elasticity of which has been destroyed by heating to redness. 
If the substance under experiment contains nitrogen, the plug 
of asbestos must be displaced by one of copper turnings, which 
serves to reduce any oxides of nitrogen, and thus ensure the 
escape of nitrogen itself. The water produced when the pre- 
pared tube is heated is collected in a small U-tube containing 
pieces of chloride of calcium, or pumice-stone moistened with 
sulphuric acid (Fig. 86) ; the carbonic acid (/ax in a series of 
bulbs (Fig. 86) containing solution of potash (sp. gr. about 
1.27). These bulbs may be purchased at any apparatus-shop. 
Ths chloride-of-calcium tube is fitted by a good cork to the 
combustion-tube, the potash-bulbs by a short piece of India- 
rubber tubing to the chloride-of-calcium tube. The potash- 
bulbs may carry a short light tube containing a rod of caustic 
Fig. 86. 
potash three or four centimetres long ; this serves to arrest any 
moisture that might be carried away from the solution of pot- 
ash by the dried expanded air which escapes during the opera- 
tion. The combustion-tube having been placed in the furnace, 
Chloride-of-Calcium Tubes and Potash-bulbs 614 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
and the drying-tube and potash-bulbs weighed and detached, 
the gas is lit under the asbestos, and, when the tube is red hot, 
the flame slowly extended until nearly the whole tube is at the 
same temperature, the operation being conducted at such a 
rate that bubbles of gas escape through the potash-bulbs at 
about the rate of one per second. When no more gas passes, 
the extremity of the tube containing the chlorate of potassium 
is gently heated until oxygen ceases to be evolved ; the quilled 
extremity of the combustion-tube is then broken, and air, dried 
and freed from carbonic acid, drawn slowly through the appa- 
ratus by suction through an India-rubber tube fixed on the free 
end of the potash-bulbs; perfect combustion of carbon and re- 
moval of all carbonic acid gas are thus ensured. The drying- 
tube and bulbs are disconnected and weighed, the increase in 
weight due to carbonic acid gas and water respectively noted, 
and the percentages of carbon, hydrogen, and (by loss) oxygen 
calculated. This method is that of Liebig, with modification 
by Bunsen; good combustion-furnaces are those known as 
Hofmann’s and Griffin’s. 
Chromate of lead can he used for combustion in place of oxide 
of copper. Its advantages are, its less hygroscopic nature, and 
the greater readiness with which it yields its oxygen to organic 
bodies when heated with them. It must not, however, be used 
with bodies containing nitrogen, since it would convert so large 
a proportion of the nitrogen into nitric oxide or higher oxide 
of nitrogen that it would be necessary to use an inconveniently 
long layer of copper turnings to reduce these oxides, and so 
prevent their absorption in the series of bulbs containing the 
solution of potash. Organic bodies, however, containing sul- 
phur, bromine, iodine, or chlorine are burnt with advantage 
by means of chromate of lead. If oxide of copper were used 
with bodies containing sulphur, it would be necessary to place 
an additional tube containing peroxide of lead between the 
chloride-of-ealcium tube and the potash-bulbs in order to absorb 
the sulphurous anhydride formed; this is entirely obviated by 
using chromate of lead, which itself retains the whole of the 
sulphur. Again, if bodies containing chlorine, iodine, or bro- 
mine are burnt by means of oxide of copper, then volatile 
chloride, iodide, or bromide of copper is formed, and, collecting 
in the chloride-of-calcium tube, vitiates the result with regard 
to the hydrogen; by using chromate of lead, however, the 
chlorine, iodine, and bromine are respectively retained in the 
combustion-tube as chloride, bromide, and iodide of lead. 
In order to render the chromate fit for use, it is first fused 
and poured out on a clean iron plate ; when cool it is powdered, CARBON, HYDROGEN, OXYGEN, NITROGEN. 
and heated in a long tube throughout its whole length, while 
air, dried by passing through chloride of calcium or strong 
sulphuric acid, is drawn over it; when the color of the chro- 
mate changes to brown the heat can be withdrawn and the 
extremity of the tube farthest from the drying apparatus closed, 
so that the air in passing into the tube on cooling may be quite 
dry ; when cool the drying-tube is removed, the extremity 
securely corked, and the carbonate of lead is ready for direct 
transference to the combustion-tube. 
The general manipulations for substances containing nitrogen 
resemble the foregoing so far as the use of a combustion-tube 
and furnace and collection of 
the ammoniacal gas are con- 
cerned. The combustion-tube 
must be quilled at one end, and 
about a third of a metre long. 
The soda-lime is made by slak- 
ing quicklime with a solution 
of soda, of such a strength that 
about two parts of quicklime 
shall be mixed with one of hy- 
drate of sodium, drying the prod- 
uct, heating to bright redness, and finally powdering; it should 
be preserved in a well-closed bottle. Some of the soda-lime is 
introduced into the tube, then layers of substance and soda- 
lime, mixture effected by a wire, more soda-lime added, and 
lastly a plug of asbestos. Bulbs (Fig. 87), known as those of 
Will and Varrentrapp (the originators of the method), contain- 
ing hydrochloric acid of about 25 per cent., are then fitted by 
a cork, and the tube heated in a furnace to a not too bright red 
heat, or some of the produced ammonia may be decomposed. 
When gas ceases to pass and combustion is considered to be 
quite complete, the tube is allowed to cool somewhat. The 
quill is then broken, and aspiration continued slowly until 
ammoniacal gas may be considered to have been all absorbed 
by the acid. The bulls are disconnected, tbeir contents and 
rinsings poured into a small dish, solution of perchloride of 
platinum added, and the operation completed, as in the estima- 
tion of ammonium and potassium salts (vide pp. 584 and 586). 
Liquids are analyzed by a similar method to that adopted for 
solids, volatile liquids being enclosed in small bulbs having a 
long quill. These are weighed previously to and after the in- 
troduction of the liquid; just before being dropped into the 
combustion-tube the quill is broken. 
Formulse.—From the percentage composition of an organic 
Fig. 87. 
Nitrogen-bulbs. G16 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
substance an empirical formula may be deduced by dividing 
the weight of each constituent by its atomic weight, and con- 
verting the product into the simplest whole numbers ; a rational 
formula by ascertaining the proportion in which the substance 
unites with a radical or body having a known combining pro- 
portion, etc. (vide p. 428). 
Chlorine, bromine, or iodine contained in an organic sub- 
stance is usually estimated by heating to redness a given 
weight of the material with ten times as much pure lime in a 
combustion-tube. Chloride, bromide, or iodide of calcium is 
thus produced. While still hot the tube is plunged into water, 
the mixture of broken glass and powder treated with pure 
diluted nitric acid in very slight excess; the filtered liquid pre- 
cipitated by nitrate of silver, and the chloride, bromide, or iodide 
of silver collected, washed, dried, and weighed. 
Sulphur, phosphorus, and arsenicum in organic salts may be 
estimated by gradually heating in a combustion-tube 1 part of 
the substance with a mixture of 10 parts nitre, 2 dried carbo- 
nate of sodium (in order to moderate deflagration), and 30 chlo- 
ride of sodium. The product is dissolved in water acidulated 
by nitric acid, the sulphuric radical precipitated and estimated 
as sulphate of barium, the phosphoric and arsenic radicals as 
ammonio-magnesium phosphate or arseniate. 
QUININE OR QUINIA. 
De Vry’s Method for the Separation of the Mixed Alkaloids 
from Cinchona-bark.—This is the method adopted for the assay 
of cinchona-bark in the United States Pharmacopaeia: Twenty 
grammes of powdered and sifted bark, dried at 100° C., are 
mixed with milk of lime made of 5 grammes of dry slaked 
lime and 50 grammes of water. This mixture is slowly dried, 
and when entirely dry heated in a flask with 200 c.c. of very 
strong alcohol (about 95 per cent.) till it boils. After well 
shaking, the clear liquid is poured by degrees into a percolating 
tube. The flask is then washed with 200 c.c. more of the same 
alcohol, and the liquid passed through the percolator. After 
this has run through, a little clear, colorless liquid may be 
further collected by pouring into the percolator successive 
small quantities of distilled water. The united clear liquors 
are now slightly acidulated with weak sulphuric acid, whereby 
a precipitate of sulphate of calcium is formed. When this 
has subsided the greater part of the liquid may be decanted 
and the rest passed through a small filter. From the clear so- 
lution most of the spirit is distilled off-, the residue poured into QUININE OR QUINfA. 
a capsule, and the still washed with a little weak spirit, the 
washings being added to the liquid in the capsule. The cap- 
sule is now heated on a water-bath till free from alcohol, and 
the remaining liquor, which contains all the alkaloids in the 
form of acid sulphates, is, after cooling, passed through a small 
filter. On the filter remains a mixture of quinovine* and fatty 
substances, which must be repeatedly washed with water slight- 
ly acidulated with sulphuric acid, till the washings are no longer 
rendered turbid by caustic soda. The filtrate, concentrated 
over a water-bath, is, while still warm, precipitated by a large 
excess of caustic soda. This precipitation from a warm solu- 
tion has the advantage of rendering the alkaloids less volu- 
minous, and therefore capable of being more easily washed. 
(Should the alkaloids melt, as is sometimes the case under this 
treatment, the liquid must be cooled and the fused alkaloids 
carefully powdered before proceeding to the next step of the 
process.) The precipitate is next placed on a small filter, 
washed with the smallest possible quantity of xlistilled water 
(sufficient to remove the soda-salt without dissolving the qui- 
nine, etc.) ; the filter is laid on blotting-paper, and this is re- 
newed until the mixed alkaloids can easily be removed from 
the filter without adhering to it: this can be done before they 
are quite dry, but requires some practice. They are then 
heated in a tared capsule on a water-bath till they cease to 
lose weight. The observed weight multiplied by five gives the 
percentage of mixed alkaloids in the bark. The intensely yel- 
low alkaline liquor separated from the alkaloids contains still 
a small quantity of quinovine, which can be separated by acidi- 
fying with hydrochloric acid. 
Assay of Mixed Alkaloids for Quinine.—The official (U.S. P.) 
method is as follows : “To the total alkaloids from 20 grammes 
of cinchona, previously weighed, add distilled water acidulated 
with diluted sulphuric acid until the mixture remains for ten 
or fifteen minutes after digestion just distinctly acid to test- 
paper. Transfer to a weighed beaker, rinsing with distilled 
water, and adding of this enough to make the whole weigh 
seventy times the weight of the alkaloids. Add now, in drops, 
solution of soda previously well diluted with distilled water 
until the mixture is exactly neutral to test-paper. Digest at 
60° C. (140° F.) for five minutes, then cool to 15° C. (59° F.), 
and maintain at this temperature for half an hour. If crys- 
* This is strictly a mixture of quinovine and quinovic acid, but, as 
quinovine is by far the larger constituent, I actually prefer the name 
of quinovine for the mixture.—De Vrij. 618 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
tals do not appear in the glass vessel, the total alkaloids do not 
contain quinine in quantity over eight per cent, of their weight 
(corresponding to nine per cent, of sulphate of quinine, crystal- 
lized). If crystals appear in the mixture, pass the latter 
through a filter not larger than necessary, prepared by drying 
two filter-papers of two to three and a half inches (5 to 9 cen- 
timetres) diameter, trimming them to an equal weight, folding 
them separately, and placing one within the other so as to 
make a plain filter fourfold on each side. When the liquid 
has drained away, wash the filter and contents with distilled 
water of a temperature of 15° C. (59° F.), added in small 
portions, until the entire filtered liquid weighs ninety times the 
weight of the alkaloids taken. Dry the filter, without sepa- 
rating its folds, at 60° C. (140° F.), to a constant weight, cool, 
and weigh the inner filter and contents, taking the outer filter 
for a counterweight. To the weight of effloresced sulphate of 
quinine so obtained add 11.5 per cent, of its amount (for water 
of crystallization), and add 0.12 per cent, of the weight of the 
entire filtered liquid (for solubility of the crystals at 15° C. or 
59° F.). The sum in grammes, multiplied by Jive, equals the 
percentage of crystallized sulphate of quinine equivalent to 
the quinine in the cinchona.” 
I)e Vrij's Method for the Separation and Quantitative Deter- 
mination of All the Different Cinchona Alkaloids.—This is based 
upon the following facts (nomenclature adopted by the Quino- 
logical Congress of Amsterdam, 1877) :— 
1. The great solubility of quinine and amorphous alkaloids 
in ether, and the relative insolubility of quinidine, cinchonidine, 
and cinchonine in this liquid. 
2. The great solubility of the iodosulpliate of the amorphous 
alkaloid in alcohol of at least 90 per cent., and the very slight 
solubility of the iodosulpliate of quinine (Herapathite) in the 
same. 
3. The great difference in solubility between the tartrate of 
cinchonidine and the tartrates of cinchonine and quinidine— 
the first being soluble in 1265 parts of water at 10° C., the 
second in 35.6 parts of water at 16° C., and the third in 38.8 
parts of water at 15° C. 
4. The great difference in solubility between the hydriodate 
of quinidine and the hydriodates of cinchonidine and cincho- 
nine in water and alcohol. One part of hydriodate of quini- 
dine requires 1250 parts of water at 15° C. or 110 parts of 
alcohol; the same salt of cinchonidine, 110 parts of water or 
3 parts of alcohol; and that of cinchonine, 128 of water or 3 
of alcohol. QUININE OR QUINIA. 
619 
These facts are applied to the separation and determination 
of the different cinchona alkaloids in the following manner:— 
A. Determination of Quinine.—1. Preparation of the Iodo- 
snlphate of Chinioidin. One part of commercial quinoidin 
(Sulphate of Chinoidin is identical with Sulphate of Amor- 
phous Quinine, prepared according to Dr. De Vrij’s process by 
Messrs. Howard & Sons, Stratford, London) is heated on a 
water-bath with two parts of benzol, whereby the quinoidin 
is partly dissolved. The cold clear benzol solution is shaken 
with an excess of weak sulphuric acid, whereby a watery solu- 
tion of acid sulphate of chinioidin is obtained. After ascer- 
taining in a small part of this solution the amount of amor- 
phous alkaloid contained in it, so that its whole quantity in the 
solution may be known, the clear solution is poured into a large 
capsule. For every 2 parts of amorphous alkaloids contained 
in the solution, 1 part of iodine and 2 parts of iodide of potas- 
sium are dissolved in water. This solution is slowly added 
under continuous stirring to the liquid in the capsule, so that 
no part of it comes into contact with an excess of iodine. By 
this addition an orange-colored flocculent precipitate is formed 
of iodosulphate of chinioidin, which either spontaneously or 
by a slight elevation of temperature collapses into a dark 
brown-red colored resinous substance, whilst the supernatant 
liquor becomes clear and slightly yellow-colored. This liquor 
—which, if the prescription is strictly followed, must still con- 
tain some amorphous alkaloid as a proof that no excess of 
iodine has been used—is poured off and the resinous substance 
is washed by heating it on a water-bath with distilled water. 
After washing, the resinous substance is heated on the water- 
bath till all the water has been evaporated. It is then soft 
and tenacious at the temperature of the water-bath, but be- 
comes hard and brittle after cooling. One part of this sub- 
stance is now heated with 6 parts of alcohol of 92 to 95 per 
cent, on a water-bath, and is thus dissolved, and the solution 
allowed to cool. In cooling, a part of the dissolved substance 
is separated. The clear dark brown-red colored solution is 
evaporated on a water-bath, and the residue dissolved in 5 
parts of cold alcohol. This second solution leaves a small 
part of insoluble substance. The clear dark brown-red colored 
solution obtained by the separation of this insoluble matter 
either by decantation or filtration constitutes the reagent which, 
under the name of “ iodosulphate of chinioidin,” Dr. De Vrij 
uses both for the qualitative and quantitative determination of 
the crystallizable quinine in barks. 
2. Application of the Reagent. To determine the quantity 020 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
of quinine contained in the mixed alkaloids obtained from a 
cinchona-bark, 1 part of these alkaloids* is dissolved in 20 
parts of alcohol of 92 to 95 per cent., containing 15 per cent, 
of H2S04,f to obtain an alcoholic solution of the acid sulphates 
of the alkaloids, and this solution is diluted with 50 parts of 
pure alcohol. From this solution the quinine is separated at 
the ordinary temperature by adding carefully, by means of a 
pipette, the above-mentioned solution of iodosulphate of chin- 
ioidin as long as a dark brown-red precipitate of iodosulphate 
of quinine (Herapathite) is formed. As soon as all the qui- 
nine has been precipitated, and a excess of the reagent 
has been added the liquor acquires an intense yellow' color, 
The beaker § containing the liquor writh the precipitate is now 
covered by a watch-glass, and heated till the liquid begins to 
boil and all the precipitate is dissolved. The beaker is then 
left to itself, and in cooling the Herapathite is separated in 
the well-known beautiful crystals. After tw'elve hours’ rest 
the beaker is weighed to ascertain the amount of liquid w'hich 
is necessary in order to be able to apply later the necessary 
correction, for although the quinine-Herapathite is very slightly 
soluble in cold alcohol, it is not insoluble.|| The clear liquid 
is poured off*|[ as far as possible on a filter, leaving the majority 
of the crystals in the beaker, which is now weighed again to 
*One gramme is a sufficient quantity. 
f This quantity is quite sufficient to transform the alkaloids into acid 
sulphates, for an excess of acid would increase the solubility of the 
Herapathite. 
J If cinchonidine is present in large quantity—as, for instance, in the 
alkaloids obtained from suceirubra-bark—the estimation of this slight 
excess requires a great deal of practical experience, which cannot be 
acquired without having studied the action of the reagent on a solution 
of pure cinchonidine in the quantity mentioned of pure and acid alco- 
hol. In manipulating the alkaloids of succirubra-bark, it often hap- 
pens that the first drops of the reagent, instead of producing a precipi- 
tate of quinine-Herapathite, form an orange-colored gelatinous pre- 
cipitate. In this case the further addition of the reagent is stopped 
and the beaker slightly heated, whereby the precipitate immediately 
disappears. In rubbing, then, the sides of the beakers with a glass rod, 
the quinine-Herapathite appears, and then the reagent can be safely 
added again. 
\ The conical form of beaker, commonly in use, is peculiarly adapted 
for this purpose. 
|| According to the experiments of Professor Jorgensen, 100 parts of a 
saturated solution of Herapathite in alcohol of 90 per cent, at a tem- 
perature of 16° C. contain 0.125 parts of Herapathite. 
*[f Before pouring off the whole quantity, it is safe to ascertain with a 
small portion of it if the necessary quantity of the reagent has been 
added. QUININE OH QUIN I A. 
ascertain the amount of liquid, which is noted down. The few 
crystals on the filter are now washed down in the beaker, and 
as much alcohol added as is necessary to redissolve all the 
crystals at the boiling-point. The object of this redissolving 
is to be absolutely certain that by surface attraction no trace 
of iodosulphate of einchonidine has adhered to the crystals of 
Herapathite, for these traces, if present, will remain dissolved 
after the recrystallization. After perfect cooling the weight of 
the beaker is ascertained again, the crystals of Herapathite 
carefully collected on a small filter, and the empty beaker 
weighed again. The difference in weight will indicate the 
amount of liquor which is added to that of the first liquor, and 
from the sum of this addition the necessary correction is cal- 
culated. If the operation is effected at a temperature of 1 G° 
C., the weighed quantity of the two combined liquors will in- 
dicate the correction if multiplied by 0.125 and divided by 100. 
If the temperature be lower or higher, the solubility of Hera- 
pathite at that temperature must be ascertained by experiment, 
which can be easily performed by a standard solution of hypo- 
sulphate of sodium, as 21.58 parts of iodine found by this 
reagent indicate 100 parts of Herapathite. The Herapathite 
collected on the filter is thoroughly washed with a saturated 
alcoholic solution of pure Herapathite,* and after this washing 
is completed the liquid retained by the crystals is expelled as 
much as possible by slightly knocking the sides of the funnel. 
The filter is then taken from the funnel and laid upon blotting- 
paper, often renewed, to take away as quickly as possible the 
still adhering liquid. As soon as the filter is air-dry the crystals 
of Herapathite can be completely removed from the filter and 
dried on a water-bath in one of a couple of large watch-glasses 
closing tightly upon each other, so that the weight of the sub- 
stance contained in the glass may be taken without the access 
of the air. If, after repeatedly weighing, the weight remains 
constant, it is noted down, and to it is added the product of the 
calculated correction. The sum of this addition is the total 
amount of iodosulphate of quinine obtained from the mixed 
alkaloids subjected to the operation, and from this weight the 
amount of quinine can be calculated by the use of Jorgensen’s 
formula: 4C.i0H.2lN2O2,3H.JSO1,2HI,I4. According to this for- 
mula, 1 part of Herapathite dried at 100° C. represents 0.55055 
part of pure anhydrous quinine. 
B. Determination of the Other Alkaloids.—Two grammes of 
* A washing-bottle containing an excess of pure crystallized Hera- 
pathite in alcohol of 95 per cent, may be kept ready for application. 622 
G RA VIMETRIC QUANTITATIVE A X A LYSIS. 
the pulverized mixed alkaloids are dissolved in weak hydro- 
chloric acid to obtain a slightly alkaline solution measuring 70 
c.c. By adding 1 gramme of Rochelle salt to this solution the 
tartrates of quinine and cinchonidine are separated; these are 
collected on a filter, washed with a little water, and dried on a 
water-bath. One part of these tartrates represents .80844 of 
quinine and cinchonidine: from the amount of these alkaloids 
thus found the amount of quinine already ascertained is sub- 
tracted, the remainder representing the cinchonidine present. 
In the filtrate from the tartrates quinidine (if present) is pre- 
cipitated by a concentrated solution of potassium iodide; one 
part of the dried hydriodate representing .86504 of crystallized 
quinidine. The remaining solution is treated with caustic 
soda, and the precipitate (if any) washed with ether. The 
residue represents the amount of cinchonine. Finally, by dis- 
tilling the ether from the washings can be ascertained the 
amount of amorphous alkaloid, which often, in the case of 
analysis of Indian barks, contains traces of quinamine. 
Prollius s Method for the Estimation of Total Alkaloids in 
Cinchona-bark, as modified by De Vrij.—The principle of the 
method referred to consists in using for the extraction of the 
alkaloids a mixture of 88 parts (by weight) of ether, 8 of 
alcohol (92 to 95 per cent.), and 4 of liquid ammonia. Prollius 
directs 10 grammes of this liquid to be taken for every gramme 
of bark, but De Vrij recommends the proportion of menstruum 
to be doubled. 10 grammes of finely-powdered bark are intro- 
duced into a well-closed bottle, and, after being carefully tared, 
200 grammes of the ethereal liquid are added. The whole is 
now shaken at intervals during one hour (Biel says four hours), 
this length of time having been ascertained by comparative 
experiments to be sufficient. The bottle is then again weighed, 
and if evaporation has taken place the necessary quantity of 
ether mixture is added. As much as possible of the clear 
liquid is now poured off into a flask, and the bottle again 
weighed; the difference in weight gives the amount of solution 
taken. The ether is then recovered by distillation, and the 
residual liquid, containing alkaloid and waxy matter, is trans- 
ferred to a tared porcelain dish and glass rod, the flask being 
washed with a little spirit. The evaporation is now continued 
on the water-bath until the weight is constant. This gives the 
amount of crude alkaloid. For instance, 10 grammes of succi- 
rubra-bark were digested with 200 grammes of ethereal liquid : 
159.8 grammes of the clear solution gave a residue of 0.78 
gramme, or 9.76 per cent, of crude alkaloid. 
To estimate the pure alkaloids, the crude residue is dissolved QUININE OR QUINIA. 
623 
in dilute hydrochloric acid, filtered, washed as long as the 
washings precipitate with solution of soda, and the whole made 
alkaline and shaken with chloroform. After standing twelve 
hours the clear chloroformic solution is run into a flask and 
evaporated by distillation. The residue is transferred with a 
little spirit to a tared dish and stirrer, and heated on the water- 
bath till the weight is constant. Particular attention should 
be paid to the latter point. In the instance referred to 0.648 
gramme of alkaloid was obtained, equivalent to 8.11 per cent., 
or about 14 per cent, less than the amount of crude alkaloid. 
By estimating the crude alkaloid and deducting 1£ per cent., 
a result will be arrived at, with loss of but little time, which, 
for the practical purposes of the pharmacist, will be sufficiently 
near the truth. 
Carles's Process for the Valuation of Cinchona-barks.—An 
average sample of the bark is reduced to fine powder and 
passed through a sieve without residue. Twenty grammes are 
then taken and intimately mixed in a mortar with 8 grammes 
of slaked lime previously mixed with 35 grammes of water. 
This mixture, spread on a plate, is dried in the air in summer 
or on a water-bath at other times. When all the moisture has 
evaporated, the lumps are broken up and the powder packed in 
a percolator with a piece of lint at the bottom. Chloroform is 
then passed through in successive portions till the mass is ex- 
hausted. This is ascertained by receiving the last drops on a 
watch-glass, evaporating to dryness and pouring on the residue 
water acidulated with dilute sulphuric acid, then solution of 
chlorine, and lastly ammonia. When a green color is no longer 
produced it is known that all the quinine has been removed. 
When the operation is well conducted about 150 grammes of 
chloroform suffice for this purpose. The menstruum retained 
by the mass is displaced by water, and the whole of the chloro- 
form solution is either distilled or evaporated to dryness. To 
separate the alkaloids from the residue it is treated several 
times in the cold with diluted sulphuric acid (1 to 10), 10 to 12 
cubic centimetres being sufficient. This solution, thrown upon 
a moistened filter, passes through colorless and free from resin- 
ous matter. It is raised to the boiling-point and ammonia 
cautiously added, so as to leave the liquid with a slightly acid 
reaction. The sulphate of ammonium thus formed appears to 
prevent the mother-liquids from retaining sulphate of quinine 
in solution. All the quinine crystallizes out in the state of 
sulphate. After some time it is collected on a double filter, the 
mother-liquors displaced by a little water, and the crystals dried 
and weighed. It is preferable to dry completely at 100° C., 624 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
and after weighing in this state to add the 12 per cent, of 
water which is lost by this treatment. The other alkaloids re- 
tained in the mother-liquors are separated by precipitation. 
A quantitative determination of the purity of commercial sul- 
phate of quinine may be made by dissolving 1 gramme of the 
salt in 20 grammes of alcohol containing .7562 per cent, of 
sulphuric acid, adding 20 more grammes of alcohol, and preci- 
pitating the quinine as Herapathite in the manner above de- 
scribed. If pure, one gramme of quinine should yield 1.3 
grammes of Ilcrapathite (De Yrij). 
K'rner's Jest for the Purity of Sulphate of Quinine.—This 
has already been described as a qualitative test under Quinine 
(p. 386). It may be applied quantitatively in the following 
manner: 5 grammes of the sulphate to be tested are triturated 
in a mortar with a little cold water, and the whole placed in a 
stoppered bottle previously calibrated for 50 c.c. Water is 
added to 50 c.c., and the mixture is well agitated and set aside 
for a day or so. It is then filtered, and a portion of the filtrate, 
say 30 c.c., is examined. To 30 c.c. of the filtrate 42 c.c. of 
ammonia solution (sp. gr. 0.96) are added, and the mixture 
agitated. If a permanent precipitate remains it is collected on 
a filter, washed, dried at 100° C., and weighed. This weight is 
the amount of alkaloid other than quinine in 3 grammes of 
sulphate. Multiplied by 33.3, it is the percentage of alkaloid 
other than quinine, generally cinchonidine, contained in the 
specimen of sulphate. To obtain the amount of sulphate of 
cinchonidine corresponding to this percentage it must be multi- 
plied by 1.217. 
Poufs Modification of Kerners Te t for Sulphate of Cincho- 
vidine in Snljthate of Quiniw.—Dissolve 4 or 5 grammes of 
the salt in 80 to 150 c.c. of boiling water. Set aside for some 
hours or during a night. Most of the quinine sulphate is de- 
posited, while the more soluble cinchonidine sulphate remains 
in solution. Filter. To the filtrate in a bottle add ether, 
shaking occasionally, until a distinct layer of ether remains 
undissolved. Add now ammonia in excess; quinine is precipi- 
tated, and then redissolved by the excess of ammonia, while 
cinchonidine remains insoluble. Set this mixture aside for a 
few hours; any cinchonidine which may have been carried into 
solution in the ether along with the quinine will separate out 
in a crystalline state. If a weighed quantity of the original 
salt has been operated on, the separated cinchonidine may be 
collected on a filter, washed with a little ether, and weighed. 
Care must be taken that the filter does not retain quinine de- 
posited by the evaporating of the ether which held it in solution. QUININE OR QUINIA. 
This will be avoided if the flask in which the operation is con- 
ducted is of such a size that the ethereal solution of quinine 
collects in the neck; for the latter liquid may be removed by a 
pipette, a little more ether then poured in, the cork replaced, 
and the whole shaken and set aside ; and this operation repeated 
two or three times before the cinchonidine is collected. The 
cinchonidine, being thus washed with a minimum of ether, suffers 
a minimum loss. 
The quinine sulphate deposited from the first aqueous solu- 
tion should be again recrystallized and its mother-liquor treated 
as above; and even the sulphate deposited in this second 
treatment should be once more carried through the operation. 
The whole of the cinchonidine may finally be collected on one 
filter. 
The aqueous filtrates may even be evaporated, set aside, 
filtered, and the ether test again applied (Parker). 
Sulphate of quinine normally contains 14.45 per cent, of 
water; sulphate of cinchonidine, 13.17 per cent.—all given off 
at 11)0° to 115° C. The drying should therefore be effected at 
100° C., and the dried salt weighed in well-fitting weighing- 
tubes. 100 parts of cinchonidine are equivalent to 110 parts 
of sulphate of cinchonidine. 
Sulphate of cinchonidine is almost the only salt likely to 
be accidentally present in the sulphate of quinine of trade, 
much quinidine being rarely present in bark, and sulphate of 
cinchonine being sufficiently soluble to always remain in the 
mother-liquors of sulphate of quinine. The sulphate of cin- 
chonidine may vary from 1 to 12 per cent., but more usually 
is present to the extent of about 6 per cent. 
Qinnitia, U. S. P.: “ If 1 gm. of quinine be mixed, in a 
mortar, with 0.5 gm. of sulphate of ammonium and 5 c.c. of 
distilled water, the mixture thoroughly dried on the water-bath, 
the residue (which should be neutral to test-paper) agitated 
with 10 c.c. of distilled water, this mixture macerated at 15° C. 
(59° F.) for half an hour, then filtered through a small filter, 
5 c.c. of the filtrate taken in a test-tube, and 7 c.c. of water of 
ammonia (sp. gr. 0.900) then added,—on closing the test-tube 
with the finger and gently turning it until the ammonia is fully 
intermixed, a clear liquid should be obtained. If the tempera- 
ture of maceration has been 10° C. (00.8° F.), 7.5 c c. of the 
water of ammonia may be added; if 17° C. (62.6° F.), 8 c c. 
may be added. In each instance a clear liquid indicates the 
absence of more than about 1 per cent of cinchonidine and 
quinidine, and of more than traces of cinchonine.” 
Quininee Sulphas, U. S. P.: “ If 1 gm. of the salt be placed 626 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
in a porcelain capsule, and dried at a temperature of 100° C. 
(212° F.) for three hours, or until a constant weight is attained, 
the remainder, cooled in a desiccator, should weigh not less than 
0.838 gm. (abs. of more than 8 molecules, or 10.18 per cent., 
of water). If the residue thus dried at 100° C. (212° F.) be 
agitated with 10 c.c. of distilled water, the mixture macerated 
at 15° C. (59° F.) for half an hour, then filtered through a 
small filter, 5 c.c. of the filtrate taken in a test-tube, and 7 c.c. 
of water of ammonia (sp. gr. 0 960) then added,—upon treat- 
ing this liquid as described above for Quinina the results there 
given should be obtained.” 
Of the Citrate of Iron and Quinine (Ferri et Quininse Citra«, 
B. P. and U. S. P.) it is officially stated that “ 50 grains dis- 
solved in a fluidounce of water and treated with a slight excess 
of ammonia give a white precipitate, which, when collected on 
a filter, washed, and dried (at 260° F.), weighs 8 grains. 
The precipitate is almost entirely soluble in two or three 
fluidrachms of pure ether,” and the ethereal solution set aside 
for twelve hours in a small well-corked bottle yields no crystal- 
line deposit (of quinidine). 
Another Process for the Determination of the Quinine of the 
Scaled Compound.—A weighed quantity of the scale, about 4 
grammes, is dissolved in about 50 c c. of water, and the whole 
is placed in a closed separating-funnel. About the same vol- 
ume of chloroform is added, and enough ammonia to impart a 
distinctly alkaline reaction. The whole is well agitated, and 
is allowed to stand until the two layers separate. The chloro- 
formic layer is then run into a weighed dish. The aqueous 
solution is treated in this way with two more portions of chlo- 
roform, about 25 c.c. each. The mixed chloroformic solutions 
are then evaporated to dryness over a water-bath, and the 
weight of the residue determined. To the residue is added 
about 25 c. c. of water and enough dilute sulphuric acid to 
impart a decidedly acid reaction. The mixture is next heated 
over a water-bath until, the solution remaining acid, the residue 
has completely dissolved. Dilute soda solution is afterward 
added with great care until the solution is exactly neutral. 
The dish is tlien removed, and the solution allowed to cool and 
rest over night, when the quinine will have separated in crys- 
tals of ordinary sulphate. These should be collected on a 
filter, and the mother-liquor tested with litmus-paper. If it 
is acid, it must be warmed over a water-bath, and dilute soda 
solution added to exact neutralization, and the solution set 
aside as before, when some more crystal’s will probably sepa- 
rate. These are also collected, and with the former ones MORPHINE OR MORPHIA. 
627 
washed, dried at 100° C., and weighed [(C2oll2+N202)2,H2S04 = 
746], To this weight must be added 1 gramme for every 750 
c.c. of mother-liquor for quinine sulphate which it retains. 
From this weight of anhydrous quinine sulphate is calculated 
its equivalent of hydrous quinine (C20H24N2O2)2,2H2O = 684, 
the approximate formula of hydrous quinine dried over a water- 
bath. The weight thus obtained is compared with the weight 
of total alkaloid determined, both having been reduced to per- 
centages. The amount of hydrous quinine calculated from the 
crystals of sulphate should not be much below that weighed 
directly. In good specimens the difference will be about 1 
per cent. (See also a paper by Fletcher in the Pharmaceutical 
Journal for Sept. 20, 1879; also in that for Sept. 18, 1880, by 
De Yrij.) 
The official (U. S. P.) process for the assay of opium is con- 
ducted in the following manner:— 
MORPHINE OR MORPHIA. 
Grammes. 
Opium, in any condition to be valued, .... 7 
Lime, freshly slaked, 3 
Chloride of Ammonium, 3 
Alcohol, 
Stronger Ether, 
Distilled Water, each a sufficient quantity. 
“ Triturate together the opium, lime, and 20 c.c. of distilled 
water in a mortar until a uniform mixture results; then add 
50 c.c. of distilled water, and stir occasionally during half an 
hour. Filter the mixture through a plaited filter three to 
three and one-half inches (75 to 90 millimetres) in diameter 
into a wide-mouthed bottle or stoppered flask (having the 
capacity of about 120 c.c. and marked at exactly 50 c.c.), until 
the filtrate reaches this mark. To the filtered liquid (repre- 
senting 5 grammes of opium) add 5 c.c. of alcohol and 25 c.c. 
of stronger ether, and shake the mixture; then add the chlo- 
ride of ammonium, shake well and frequently during half an 
hour, and set it aside for twelve hours. Counterbalance two 
small filters ; place one within the other in a small funnel, and 
decant the ethereal layer as completely as practicable upon the 
filter. Add 10 c.c. of stronger ether to the contents of the 
bottle and rotate it; again decant the ethereal layer upon the 
filter, and afterward wash the hitter with 5 c.c. of stronger 
ether, added slowly and in portions. Now let the filter dry in 
the air, and pour upon it the liquid in the bottle, in portions, GRAVIMETKIC QUANTITATIVE ANALYSIS. 
in such a way as to transfer the greater portion of the crys- 
tals to the filter. Wash the bottle, and transfer the remaining 
crystals to the filter, with several small portions of distilled 
water, using not much more than 10 c.c. in all, and distrib- 
uting the portions evenly upon the filter. Allow the filter to 
drain, and dry it, first by pressing it between sheets of bibu- 
lous paper, and afterward at a temperature between 55° and 
00° C. (131° to 140° F.). Weigh the crystals in the inner 
filter, counterbalancing by the outer filter. The weight of the 
crystals in grammes, multiplied by twenty, equals the percent- 
age of morphine in the opium taken.” 
“ On exhausting 100 parts of opium, previously dried at a 
temperature of 105° C. (221° F.), with cold water, and evap- 
orating the solution to dryness, an extract is obtained which 
should weigh between 55 and GO parts.”—U. S. P. 
Prollius's Method for the Determination of Morphine in Opium. 
—5 to 10 grammes of opium are weighed and extracted with 
100 c.c. of 34-per cent, spirit. The resulting tincture is well 
shaken with 50 c.c. of ether and 2 c.c. of solution of ammo- 
nia in a stoppered bottle, and then allowed to stand from 
twelve to twenty-four hours. The liquids separate slowly, 
and retain, partly in the ether and partly in the alcoholic 
liquid, the coloring-matter, narcotine, and other crystalljzable 
constituents of opium, while the morphine separates in crystals 
between the two layers, and finally sinks to the bottom. The 
fluid portion is decanted, the crystals are washed with diluted 
alcohol dried at 10()° C., and weighed. 
Petit's Method.—Take 15 grammes of opium, suspend it in 
75 grammes of water, and afterward throw it upon a filter. 
Take 55 grammes of the filtrate, which represents 10 grammes 
of opium, add 3 c.c. of ammonia solution, and agitate. The 
morphine deposits rapidly in the form of a crystalline powder. 
The whole is allowed- to stand for a quarter of an hour, and 
then 27 grammes of alcohol (of 95 per cent.) are added; 
after shaking several times it is again allowed to stand for 
half an hour, and then thrown upon a tared filter. The alka- 
loid is washed upon the filter with 50 per cent, alcohol. It is 
then dried at 100° C. and weighed. 
FlUckujer s, Method.—Take of powdered opium 8 grammes, 
cold water 80 grammes; shake the mixture frequently; after 
twelve hours filter. The filter should have a diameter of 5 
inches. The operation will afford on an average G5 to 70 
grammes of clear liquid. No washing is to take place. 42.5 
grammes of the liquid are collected in a little phial, the weight 
of which has previously been noted. Next add to the solu- MORPHINE OR MORPHIA. 
629 
tion 12 grammes of alcohol (sp. gr. 0.812-0.815), 10 grammes 
of ether, and 1.5 grammes of ammonia-water of 0.960 sp. gr. 
The mixture after shaking will remain clear, and a colorless 
layer of ether will appear on its surface. The phial is corked 
and allowed to stand without further shaking. After an hour 
or two crystals of morphine begin to be formed, mostly at the 
junction of the two layers. Presently they sink to the bot- 
tom, and after a day or two the whole amount of whitish or 
white crystals of the alkaloid will have been deposited. They 
are then to be collected by using two folded filters having a 
diameter of four inches. The phial is rinsed out with a 
mixture of 6 grammes of alcohol and 5 grammes of ether, 
and lastly with 10 grammes of ether, these liquids being grad- 
ually poured on to the crystals in order to wash them. The 
funnel in the mean time is carefully covered. The crystals 
are subsequently cautiously pressed between the folds of the 
two filters, which will almost completely absorb the mother- 
liquor which the crystals of morphine may still retain. It will 
now be quite easy to remove the alkaloid neatly from the fil- 
ter ; it must be weighed in the phial, in which some crystals 
may have remained obstinately attached to the walls. The 
phial and contents, dried at 109° C., contain the whole amount 
of morphine precipitated in the hydrous condition—namely, 
Ci7H,9N03 + H20. The operator finally ascertains the purity 
of the crystals. To this end he takes 1 decigramme of the 
morphine and dissolves it in 19 grammes of lime-water. If the 
lime-water be duly saturated in the cold, the quantity men- 
tioned will be a little more than sufficient. The morphine will 
probably leave only a very trifling amount of coloring-matter, 
quite insufficient to influence appreciably the percentage of 
alkaloid. Should narcotine be present it will remain undis- 
solved. It is important to precipitate the morphine from a 
solution containing alcohol and ether. By adding ammonia to 
an aqueous solution a flocculent matter is precipitated. This 
abundant amorphous mass—an alkaloid or not, it is certainly 
far from being morphine—remains in solution if the liquid con- 
tains a little alcohol, one-third alcohol of the volume of the 
aqueous filtrate being quite sufficient for the purpose. Of no 
less importance is the action of the ether. It not only pre- 
vents the narcotine from being thrown down together with 
the morphine, but ether promotes the formation of distinct and 
pure crystals of morphine, this alkaloid separating very readily 
from a liquid saturated with ether. E. R. Squibb has pub- 
lished useful details respecting this process. 
Mylius s Method.—For the colorimetric assay of morphine in 630 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
opium by means of iodic acid see New Remedies for June, 
1881. 
The qualitative test of sugar by means of an alkaline copper 
solution (vide p. 411) may be applied in the estimation of 
sugar in sacchariferous substances. 
Process.—34.65 grammes of pure dry crystals of ordinary 
sulphate of copper are dissolved in about 250 c.c. of distilled 
water, and 173 grammes of pure crystals of the double tartrate 
of potassium and sodium are dissolved in 480 c.c. of solution 
of caustic soda of sp. gr. 1.14. The solutions are mixed, and 
water added until 1 litre of solution is obtained. 100 c.c. 
of this solution represent 3.464 grammes of sulphate of copper, 
and correspond to 0.5 of a gramme of pure anhydrous grape- 
sugar, 0.475 of cane-sugar, 0.82 of maltose, or 0.45 of starch. 
It must be preserved in a well-stoppered bottle to prevent ab- 
sorption of carbonic acid, and be kept in a dark place. Should 
it give a precipitate on boiling, a little solution of soda may 
be added when making experiments. A solution of this 
strength is officially (U. S. P.) termed “ Test-Solution of Po- 
tassio-cupric Tartrate,” or “ Fehling’s Solution.” 
Dissolve 0.475 of pure dry powdered cane-sugar in about 50 
c.c. of water, convert into grape-sugar by acidulating with sul- 
phuric acid and boiling for an hour or two, make slightly alka- 
line with carbonate of sodium, and dilute to 100 c.c. Place 
10 c.c. of the copper solution in a small flask, dilute with three 
or four times its bulk of water, and gently boil. Into the boil- 
ing liquid drop the solution of sugar from a burette, one cubic 
centimetre or less at a time, until, after standing for the pre- 
cipitate to subside, the supernatant liquid has just lost its blue 
color; 10 c.c. of the solution of the sugar should be required 
to produce this effect = 0.0475 of cane-sugar, 0.082 of mal- 
tose, or 0.05 of grape-sugar. Experiments on pure cane-sugar 
must be practised until accuracy is attained ; syrups, diabetic 
urine, and saccharated substances containing unknown quanti- 
ties of sugar may then be analyzed. 
Starch is converted into grape-sugar by gentle ebullition 
with dilute acid for eight or ten hours, the solution being final- 
ly diluted so that one part of starch, or rather sugar, shall be 
contained in about 150 of water, 
Saccharimetry.—A generic term for certain volumetric oper- 
ations undertaken with the view of ascertaining the quantity 
of sugar present in any matter in which it may be contained. 
Saccharimetry is frequently performed upon common syrup 
SUGAR. SUGAR. 
631 
(Syrupus, B. P.) and solutions which are known to contain 
nothing but cane- (ordinary) sugar, the object being merely to 
ascertain the amount present. In such a case it is only neces- 
sary to take the specific gravity of the liquid at 60° F., and 
then refer to a previously prepared Table of density and per- 
centages :— 
Specific 
gravity. 
Sugar, 
per cent. 
Specific 
gravity. 
Sugar, 
per cent. 
Specific 
gravity. 
Sugar, 
per cent. 
1.007 . . 1.8 
1.014 . . 3.5 
1.022 . . 5.2 
1.029 . . 7.0 
1.036 . . 8.4 
1.044 . . 10.4 
1.052 . . 12.4 
1.060 . . 14.4 
1.067 . . 16.3 
1.075 . . 18.2 
1.083 . . 20.0 
1.091 . . 21.8 
1.100 . . 23.7 
1.108 . . 25.6 
1.116 . . 27.6 
1.125 . . 29.4 
1.134 . . 31.5 
1.143 . . 33.4 
1.152 . . 35.2 
1.161 . . 37.0 
1.171 . . 38.8 
1.180 . . 40.6 
1.190 . . 42.4 
1.199 . . 44.3 
1.210 . . 46.2 
1.221 . . 48.1 
1.231 . . 50.0 
1.242 . . 52.1 
1.252 . . 54.1 
1.261 . . 56.0 
1.275 . . 58.0 
1.286 . . 60.1 
1.289 . . 62.2 
1.309 . . 64.4 
1.321 . . 66.6? 
1.330(b. p.)66.6? 
The sp. gr. may be taken by a hydrometer, technically 
termed a saccharometer. (The above spec, gravs. = 1° to 35° 
Baume.) 
If a liquid contains other substances besides cane-sugar, the 
test of specific gravity is of little or no value. Advantage 
may then be taken of the fact that syrup causes right-handed 
twisting of a ray of polarized light to an extent exactly pro- 
portionate to the amount of sugar in solution. The saccharine 
fluid is placed in a long tube having opaque sides and trans- 
parent ends, and a ray of homogeneous light, polarized by re- 
flection from a black-glass mirror or otherwise, is sent through 
the liquid and optically examined by a plate of tourmaline, 
Nicol’s prism, or other polarizing eye-piece. Attached to the 
eye-piece is a short arm which traverses a circle divided into 
degrees. The eye-piece and arm are previously so adjusted 
that when the ray is no longer visible the arm points to the 
zero of the scale of degrees. The saccharine solution, how- 
ever, so twists the ray as to again render it visible ; and the 
number of degrees which the eye-piece has to be rotated before 
the ray is once more invisible is exactly proportionate to the 
strength of the solution. The value of the degrees having 
been ascertained by direct experiment and the results tabulated, 
a reference to the Table at once indicates the percentage of 
sugar in the liquid under examination. Grape-sugar also pos- 632 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
sesses the property of dextro-rotation, but less powerfully 
than cane-sugar ; moreover, the former variety does not. like 
cane-sugar, suffer inversion of the direction of rotation on the 
addition of hydrochloric acid to its solution—an operation that 
I furnishes data for ascertaining the amounts of cane- and of 
grape-sugar, or of crystallizable and non-crystallizable sugar, 
present in a mixture. In using the polariscope-saccharometer 
it is convenient to employ tubes of uniform size and always to 
operate at the same temperature. Various modes are adopted 
of applying, for the purposes of quantitative analysis, the ac- 
tion of syrup on polarized light. 
ALCOHOL. 
Mulder's process for the determination of the amount of 
alcohol in wines, beer, tinctures, and other alcoholic liquids 
containing vegetable matter is as follows:—Take the specific 
gravity and temperature of the liquid, and measure off a certain 
quantity (100 cubic centimetres); evaporate to one half or less, 
avoiding ebullition in order that particles of the material may 
not be carried away by the steam. Dilute with water to the 
original bulk, and take the specific gravity at the same tempe- 
rature as before. Of the figures representing this latter spe- 
cific gravity, all over 1.000 show to what extent dissolved solid 
matter affected the original specific gravity of the liquid. Thus, 
the specific gravity of a sample of wine at 15°.5 C. is 0.9951 ; 
evaporated till all alcohol is removed and diluted with water to 
the original bulk, the specific gravity at 15°.5 C. is 1.0081; 
0.0081 represents the gravitating effect of dissolved solid mat- 
ter in 0.9951 parts of original wine. 0.0081 subtracted from 
0.9951 leaves 0.987, which is the specific gravity of the water 
and alcohol of the wine. Or divide the sp. gr. of the wine by 
the sp. gr. of the wine minus alcohol, carrying out the sum to 
four places of decimals; the quotient shows the sp. gr. of the 
water and alcohol only of the wine. On referring to a Table 
of the strengths of diluted alcohol of different specific gravi- 
ties (p. 659), 0.987 at 15°.5 C. is found to indicate a spirit 
containing 8 per cent, of real alcohol. Mulder’s process is that 
adopted officially (U. S. P.) for ascertaining the strength of 
white wine ( Vinur/l Album) and red wine ( Vinum Rubrum). 
If the foregoing operation be conducted in a retort, the liquid 
being boiled and the steam carefully condensed, the distillate, 
diluted with water to the original bulk of wine operated on, 
will still more accurately represent the amount of water and DIALYSIS. 
633 
alcohol in the wine, its specific gravity showing the percentage 
of real alcohol present. 
Dialysis (from Sta, dia, through, and kuats, lusts, a loosing 
or resolving) is a term applied by Graham to a process of 
analysis by diffusion through a septum. The apparatus used 
in the process is called a dialyzer, and is constructed and em- 
ployed in the following manner. The most convenient septum 
is the commercial article known as parchment-paper, made by 
immersing unsized paper for a short time in sulphuric acid ; it 
is sold by most dealers in chemical apparatus. A piece of this 
material is stretched over a gutta-percha hoop and secured by 
a second external hoop. Dialyzers of useful size are one or 
two inches deep and five to ten inches wide. Liquids to be 
dialyzed are poured into the dialyzer, which is then floated in a 
flat dish containing distilled water. The portion passing 
through the septum is termed the dijfmate; the portion which 
does not pass through is termed the dialysate. 
The practical value of dialysis depends upon the fact that 
certain substances will diffuse through a given septum far more 
readily than others. Uncrystallizable bodies diffuse very slowly. 
Of such matters as starch, gum, albumen, and gelatin, the last 
named is perhaps least diffusive ; hence substances of this class 
are termed colloids, or bodies like collin, which is the soluble 
form of gelatin. Substances which diffuse rapidly are most 
crystalline; hence bodies of this class are termed crystalloids. 
Solution of two parts of the following-named substances in 
100 parts of distilled water were dialyzed by Graham for 
twenty-four hours. The amounts of each substance which 
passed through the septum bore the following relations to one 
another:— 
DIALYSIS. 
Chloride of sodium 1000 
Ammonium 847 
Theine 703 
Saliein 503 
Cane-sugar 472 
Amygdalin 311 
Extract of logwood 108 
Catechu 159 
Extract of cochineal 51 
Gallo-tannic acid 30 
Extract of litmus 19 
Purified caramel 5 634 
GRAVIMETRIC QUANTITATIVE ANALYSIS. 
Ten per cent, solutions, under similar circumstances, gave 
the following results :— 
Gum-arabic 4 
Starch-sugar 266 
Cane-sugar 214 
Glycerin 440 
Alcohol 476 
Chloride of sodium 1000 
Dialyzed iron, an aqueous solution of about 5 per cent, of 
highly basic oxychloride of iron, is obtained by saturating solu- 
tion of perchloride of iron with ferric hydrate, by adding am- 
monia, or, better, carbonate of sodium, and shaking vigorously 
until the precipitated hydrate ceases to redissolve, filtering if 
necessary, placing on a dialyzer floating in distilled water, and 
displacing the fluid in the dish by water daily for a week or 
two, or until the diffusate gives no reaction with nitrate of 
silver. The crystalloids (chloride of sodium or other salt) pass 
through the dialyzer; the colloid fluid which does not pass 
through the dialyzer is the highly basic oxychloride of iron, or 
so-called “ dialyzed iron” or “ dialytic iron.” This fluid has 
very little taste of iron. Its value as a medicine has been 
questioned, its non-diffusibility suggesting that it never passes 
out of the intestinal canal, and therefore never gets into the 
blood. It is sometimes prepared by dissolving in solution of 
ferric chloride as much ferric hydrate as it will take up, with 
frequent shaking, during three or four weeks. 
The phenomena of dialysis show that crystalloids are superior 
to colloids in affinity for water. If a solution of chloride of 
sodium be placed at the bottom of a jar and covered by a hot 
solution of gelatin of sufficient strength to solidify on cooling, 
the chloride of sodium will diffuse up into the solid jelly, be- 
cause the water of the solid jelly has a greater affinity for the 
salt than it has for the gelatin. The solid jelly may obviously 
be reduced in thickness, and saline liquids placed above it; 
indeed the conditions would then be still more favorable for 
diffusion. Replace the stratum of jelly by a permanent colloid, 
such as parchment-paper; the result is the same, but the per- 
manent character of the septum admits of its practical applica- 
tion. 
Further researches on dialysis will probably throw much 
light on several important points in connection with physiolog- 
ical chemistry ; for there is little doubt that alimentary matter 
passes through the cell-walls of animals and plants by this 
process. CONCLUSION. 
635 
1055. Carbonate of potassium is said to lose 16 per cent, of water 
on exposure to a red heat; give the details of manipulation observed 
in verifying this statement. 
1056. Write a few paragraphs descriptive of the process of ulti- 
mate organic analysis. 
1057. In what forms are carbon, hydrogen, and nitrogen weighed 
in quantitative analysis? 
1058. In the combustion of .41 of a gramme of sugar, what weights 
of products will be obtained? Ans. .632 of carbonic acid gas (CO,) 
and .237 of water (II20). 
1059. IIow is cinchona assayed for mixed alkaloids? 
1060. On what facts does De Yrij found his method for the separa- 
tion and quantitative determination of all the cinchona alkaloids ? 
1061. Describe De Vrij's process for the assay of commercial sul- 
phate of quinine. 
1062. Give the official method for the estimation of morphine in 
opium. 
1063. Mention the operation necessary for the estimation of the 
proportion of sugar in saccharated carbonate of iron or in a speci- 
men of diabetic urine. 
1064. What is understood by Saccharimetry f 
1065. Give two processes for the estimation of the percentage of 
alcohol in tinctures, wines, or beer. 
1066. Define dialysis. 
QUESTIONS AND EXERCISES. 
Conclusion. 
Detailed instructions for the quantitative analysis of potable 
water, articles of food, general technical products, special 
minerals, soils, manures, air, illuminating agents (including 
solid fats, oils, spirits, petroleum, and gas), dyes, and tanning- 
materials would scarcely be in place in this volume. 
The course through which the reader has been conducted 
will, it is hoped, have taught the principles of the science of 
Chemistry, and given special knowledge concerning the appli- 
cations of that science to medicine and pharmacy, as well as 
have imparted sufficient manipulative skill to meet the require- 
ments of manufacture or analysis. The author would venture 
to suggest that this knowledge be utilized, not only in the way 
of personal advantage, but in experimental researches on chem- 
ical subjects connected with therapeutics and pharmacy. The 
discovery and publication of a new truth, great or small, is the 
best means whereby to aid in advancing the calling in which 
we may be engaged, benefit our fellow-creatures and ourselves, 
and contribute to that “ultimate end of knowledge” which 
Bacon defined as “ the glory of the Creator and the endowment 
of human life.” APPENDIX. 
TABLE OF TESTS FOR IMPURITIES IN PREPARATIONS 
OF THE UNITED STATES PHARMACOPOEIA.* 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Acaciee Gummi, 
Starch. 
Iodine. 
271 
' 
Copper, Lead, or Tin. 
Sulphuretted Hydrogen. 
254 
Iron. 
Excess of Ammonia. 
157 
Calcium. 
Oxalate of Ammonium. 
113 
Other mineral matter. 
r 
Evaporation and ignition. 
Color and odor with Pot- 
100 
Empyreumatic sub- J 
ash. 
92 
stances. 
Keduction by Permanga- 
Acidum Aceticum, - 
i 
nate of Potassium. 
92 
Organic matter. 
Sulphuric Acid. 
320 
Nitric Acid. 
Sulphuric Acid and Sul- 
phate of Iron. 
286 
Sulphuric Acid. 
Chloride of Barium. 
307 
Hydrochloric Acid. 
Nitrate of Silver. 
264 
Sulphurous Acid. j 
Nascent Hydrogen. 
Nitrate of Silver. 
304 
304 
Acid. Acetic. Gin- 
Sulphurous Acid. 
Nascent Hydrogen, or Ni- 
dale, 
trate of Silver. 
Chloride or Nitrate of Ba- 
304 
Sulphuric Acid. 
riuin. 
307 
Hydrochloric Acid. 
Nitrate of Silver and Ni- 
Acidum Boricum, 
Lead, Copper, Iron, 
trie Acid. 
Sulphide of Ammonium. 
264 
157 
etc. 
Calcium. 
Oxalate of Ammonium. 
113 
Sodium Salts. 
In flame on Pt. wire. 
87 
Chlorobenzoic Acid. 
Cupric Oxide and flame- 
test. 
190 
Acidum. Benzol- 
Cinnamic Acid. 
Permanganate of Potas- 
cumy 
siuin and water. 
334 
Other organic matter. 
Odor; warm Sulphuric 
Acid. 
334 
Acidum Carboli- 
Creasote and Cresylic 
Glycerin, and dilution. 
cwn, 
Acid. 
oxidation, etc. 
449 
Acidum Chromi- 
More than trace of Sul- 
Chloride of Barium. 
307 
cum, 
phurio Acid. 
* The manipulations 
necessary to be observed in testing for impurities will be 
found described in the paragraphs treating of those substances, 'lhe Table also 
includes references to processes for ascertaining deficiency in strength of official 
articles. 
The other characters and tests of pharmacopoeial chemical compounds have been 
given in connection with the respective synthetical and analytical reactions. 638 
APPENDIX. 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
r 
Tartaric and Oxalic 
Acetate of Potassium and 
Acids. 
Alcohol. 
319 
Tartaric Acid. 
Bichromate of Potassium. 
324 
Acidum Citricum, 
Lead or Copper. 
Sulphuric Acid. 
Sulphuretted Hydrogen. 
Chloride or Nitrate of Ba- 
218 
rium. 
307 
Mineral matter. 
Incineration. 
100 
Acidum Gallicnm, 
Tannic Acid. 
Gelatin, Alkaloidal Salts, 
Tartarated Ant’ny. etc. 
354 
Acidum Hydrobro- 
Sulphuric Acid. 
Chloride or Nitrate of 
mic. Dilut., 
Barium. 
Chloride or Nitrate of 
307 
Sulphuric Acid. 
Barium. 
307 
Sulphurous Acid. 
Nascent Hydrogen. 
304 
Acidum Hydro- 
Arsenic. 
Sulphuretted Hydrogen; 
chloricum, 
Lead, Iron, or Copper. 
Copper. 
Sulphydrate of Ammo- 
169 
nium. 
157 
Free Chlorine. 
Sulphuric Acid. 
Iodide of Potassium. 
Chloride or Nitrate of 
271 
Acid. Ifi/drocyan- 
Barium. 
307 
icum, Dil., 
Hydrochloric Acid. 
Ppt. by Nitrate of Silver; 
insol. in Nitric Acid. 
264 
Hydrochloric Acid. 
Sulphuric Acid. 
Nitrate of Silver. 
Chloride or Nitrate of 
264 
Barium. 
307 
Sarcolactic Acid. 
Sulphate of Copper. 
345 
Acidum Lacticum, 
Lead or Iron. 
Ammonia and Sulphy- 
drate of Ammonium. 
157 
Sugars. 
Potassio-cupric Tartrate. 
630 
Glycerin. 
Hydrate of Zinc and Ab- 
solute Alcohol. 
455 
Other organic matter. 
Cold Sulphuric Acid. 
334 
Iron or Lead. 
Ammonia and Sulphy- 
drate of Ammonium. 
157 
Copper. 
Excess of Ammonia. 
189 
Mineral matter. 
Evaporation and gentle 
ignition. 
100 
Arsenic Acid. 
Excess of Potash, boil 
Acidum Nitricum, - 
Sulphuric Acid. 
with Zinc. 
Chloride or Nitrate of 
171 
Barium. 
307 
Hydrochloric Acid. 
Nitrate of Silver. 
264 
Free Iodine. 
Mucilage of Starch. 
271 
Iodic Acid. 
Starch and Sulphuretted 
Hydrogen. 
293 
Palmitic and Stearic 
Saponification, Acetic 
Acidum Oleicum, - 
Acids. 
Acid, and Acetate of 
Lead. 
463 
Fixed Oils. 
Alcohol. 
463 
Acidum Phosphor-) 
Phosphorous Acid. 
Nitrate of Silver; Mercu- 
ric Chloride. 
342 
Arsenic Acid. 
Sulphuretted Hydrogen. 
173 APPENDIX. 
639 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
[ 
Nitric Acid. 
Sulphuric Acid and Fer- 
rous Sulphate. 
286 
Acidum Phosphor- 
icum9 
Sulphuric Acid. 
Chloride or Nitrate of 
Barium. 
307 
Hydrochloric Acid. 
Nitrate of Silver and Ni- 
trie Acid. 
264 
Pyro- or Meta-pbos- 
phoric Acid. 
Hydrochloric Acid. 
Tincture of Chloride of 
Iron, Albumen. 
Nitrate of Silver and Ni- 
347 
trie Acid. 
264 
Organic matter and 
Crystallization from Alco- 
Acidum Salicyl- 
icumy 
Iron. 
hoi (white). 
Organic matter. 
Cold Sulphuric Acid. 
334 
Carbolic Acid. 
Chlorate of Potassium, 
' 
Hydrochloric Acid, and 
Ammonia. 
451 
Lead. 
Alcohol. 
211 
Nitric Acid. 
Solution of Ferrous Sul- 
phate. 
286 
Hydrochloric Acid. 
Sulphate of Silver. 
265 
Acidum Sulphuri- 
Lead, Arsenic, or Cop- 
Sulphuretted Hydrogen. 
218 
cum, 
per. 
Iron. 
Excess of Ammonia. 
157 
Mineral matter. 
Incineration. 
100 
Arsenious or Sulphur- 
Nascent Hydrogen. 
171 
ous Acid. 
Acidum Sulphuro- 
Much Sulphuric Acid. 
Chloride of Barium. 
307 
sum, 
Acidum Tannicum, 
Mineral matter. 
Incineration. 
100 
Lead or Copper. 
Sulphuretted Hydrogen. 
218 
Iron. 
Ammonia and Sulphy- 
Acidum Tartar- 
drate of Ammonium. 
151 
icum, 
Sulphuric Acid. 
Chloride of Barium. 
307 
Mineral matter (more 
Incineration. 
100 
than trace). 
Alkalies. 
Litmus. 
94 
Adeps, 
Starch (flour). 
Iodine. 
271 
Chloride (of Sodium). 
Nitrate of Silver. 
264 
Excess of water. 
Drying on water-bath. 
610 
sEthcr, 
. 
Mineral matter. 
Evaporation. (See also 
./Ether Fortior.) 
100 
( 
Mineral matter. 
Evaporation. 
100 
JEther Aceticus, 
Acetic Acid. 
W ater. 
Test-papers. 
Specific gravity. 
94 
436 
Alcohol. 
Boiling-point. 
436 
Acid. 
Test-papers. 
94 
JEther Fortior, 
Excess of water and 
Agitation with Glj’cei in : 
Alcohol. 
boiling-point. 
434 
f 
Fusel Oil. 
Water and Glycerin. 
429 
Amylic Alcohol. 
Sulphuric Acid. 
430 
Alcohol, 
Methyl Alcohol. I 
Aldehyd and Oak > 
Solution of Potash. 
430 
Tannin. ) APPENDIX. 
Table of Tests— Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
f 
Methyl Alcohol. 
Carbonate of Lead and 
Alcohol, \ 
Permanganate. 
430 
Fixed residue or resin. 
Evaporation. 
100 
Alcohol Absolu- 
W ater. 
Sulphate of Copper (an- 
turn, 
hydrous). 
188 
Ammonia Alum. 
Potash or Soda. 
96 
Zinc or Lead. 
Sulphydrate of Ammo- 
Alumen, 
More than trace of 
nium in alkaline filtrate. 
Ferrocyanide of Potas- 
133 
Iron. 
sium. 
157 
Iron. 
Ferrocyanide of Potas- 
sium. 
157 
Sulphuric Acid. 
Chloride or Nitrate of 
Alwminii Hydras, 
Zinc or Lead. 
Barium. 
Sulphydrate of Ammo- 
307 
nium. 
133 
Alkaline Salts (more 
Solution in water and 
than trace). 
evaporation. 
100 
Alumina Sulphas, 
Iron. 
Ferrocyanide of Potas- 
sium. 
157 
Ammonii Benzoas, 
Fixed Salts. 
Incineration. (See also 
Acidum Benzoicum.) 
100 
Bromate (of Ammo- 
Diluted Sulphuric Acid. 
268 
nium). 
Iodide (of Ammo- 
Chlorine-water and muci- 
Ammonii Bromi- 
nium). 
lage of Starch. 
271 
diim, 
Sulphate (of Ammo- 
Chloride or Nitrate of 
nium). 
Barium. 
307 
More than 3 per cent. 
Quantitative Analysis. 
569 
of Chloride. 
Sulphate (of Ammo- 
Chloride or Nitrate of 
nium). 
Barium. 
307 
Ammonii Carlo- 
Chloride (of Ammo- 
Nitrate of Silver. 
264 
nium). 
IlCl 8 y 
Metals. 
Sulphuretted Hydrogen. 
218 
Empyreumatic sub- 
Excess of Sulphuric Acid 
stances. 
and Permanganate. 
92 
Barium. 
Sulphuric Acid. 
102 
Metals. 
Sulphuretted Hydrogen or 
Sulphydrate of Ammo- 
Ammonii Chlori- 
dum, 
nium. 
218 
Sulphate (of Ammo- 
Nitrate of Barium. 
307 
nium). 
Iron. 
Ferrocyanide of Potas- 
sium. 
157 
Sulphate (of Ammo- 
Chloride or Nitrate of 
nium). 
Barium. 
307 
Chloride and Bromide 
Ammoniacal solution, Ni- 
Ammonii Iodidum, 
(excessive). 
trate of Silver, and Ni- 
tric Acid; and Quantita- 
tive Analysis. 
271 
Iron. 
Ferrocyanide of Potas- 
sium. 
157 APPENDIX. 
641 
Table or Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page 
Ammonii Indicium, 
Free Iodine. 
Mucilage of Starch. 
271 
r 
Sulphate (of Ammo- 
Chloride or Nitrate of 
Ammonii Nitras, 
nium). 
Barium. 
307 
Chloride (of Ammo- 
Nitrate of Silver. 
264 
l 
r 
nium). 
Metals. 
Sulphuretted Hydrogen or 
Sulphide of Ammonium. 
218 
Ammonii Phos- 
phas, 
Sulphate (of Ammo- 
Chloride or Nitrate of 
nium). 
Barium. 
307 
Chloride (of Ammo- 
Nitrate of Silver. 
264 
nium). 
Lead or Iron. 
Sulphide of Ammonium. 
218 
Ammonii Sulphas, 
Chloride (of Ammo- 
Nitrate of Silver. 
264 
nium). 
Acetate (of Ammo- 
Ferric Chloride. 
297 
nium). 
Ammonii Valeri- 
Sulphate (of Ammo- 
Nitrate or Chloride of 
ana 8. 
nium). 
Barium. 
307 
Chloride (of Ammo- 
Nitrate of Silver. 
264 
Amyl Nitras, 
nium). 
Excess of free acid. 
Quantitative Analysis. 
563 
' 
Sulphate (of Potas- 
Chloride of Barium. 
307 
sium). 
Chloride (of Potas- 
Nitrate of Silver. 
264 
Antimonii et Po- 
tass ii Tartras, 
sium). 
Iron and other metals. 
Ferrocyanide of Potas- 
sium and Acetic Acid. 
157 
Calcium. 
Oxalate of Ammonium. 
113 
Arsenic. 
Nascent Hydrogen and 
Nitrate of Silver. 
171 
Antimonii Oxi- 
Same as Ant. ct Pot. 
dnm, 
- 
Tait., q. n. 
Metallic Sulphides. 
Ignition with Nitrate of 
Antimonii Su/phi- 
Soda. 
174 
dnm Puri/., 
Arsenic. 
Ammonio-nitrate of Sil- 
ver. 
174 
Antimonium Sul- f 
Sulphate (of Sodium). 
Chloride or Nitrate of 
phuratum, 
Barium. 
307 
Metallic impurities. 
Sulphydrate of Ammo- 
218 
ilium. 
Aquay 
Organic matter. 
Permanganate of Potas- 
sium. 
126 
Empyreumatic sub- 
Neutralization with Sul- 
stances. 
phuric Acid and odor; 
also Permanganate. 
92 
Carbonate. 
Lime-water. 
311 
Aqua Ammoniee, 
Sulphate. 
Chloride or Nitrate of 
307 
Barium. 
Chloride. 
Nitrate of Silver. 
264 
Metals. 
Sulphuretted Hydrogen. 
218 
Calcium. 
Oxalate of Ammonium. 
113 
Aqua Aurantii 
Flornm, 
Metals (Pb, Cu, Sn). 
Sulphuretted Hydrogen. 
218 642 
APPENDIX. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Metals. 
Sulphuretted Hydrogen or 
Sulphydrate of Ammo- 
nium. 
218 
Sulphuric radical. 
Chloride or Nitrate of 
Barium. 
307 
Aqua Destillata, 
Hydrochloric radical. 
Nitrate of Silver. 
264 
Calcium. 
Oxalate of Ammonium. 
113 
Ammonia or its salts. 
Mercuric Chloride and 
Carbonate of Potassium, 
or Nessler’s Beagent. 
558 
Organic matter. 
Permanganate of Potas- 
sium. 
126 
Chloride (of Silver). 
Boil with Carbonate of 
Argenti Iodidtim, ■ 
Argenti Nitron, j 
Ammonium, and add 
Nitric Acid. 
265 
Metallic impurities. 
Hydrochloric Acid and 
evaporation. 
265 
Argenti Oxidum, 
Carbonate. 
Acid (Hydrochloric). 
311 
Atropina, 
Mineral matter. 
Incineration. 
100 
Atropium Sulphas, 
Mineral matter. 
Incineration. 
100 
Anri ct Sodii Ohio- ) 
rid am, J 
Free Acid. 
Ammonia fumes. 
97 
Aurum, 
Copper or Silver. 
Nitric Acid. 
242 
Balsamum Peruvi- f 
Volatile Oil. 
Distillation with water. 
469 
anum, j 
Gurjun Balsam. 
Heavy Hydrocarbons. 
Bisulphide of Carbon. 
Evaporation at low temp., 
480 
and odor. 
448 
Pyrogenous prod-) 
Spirit of Ammonia and 
Benzinum, 
ucts and Sulphur > 
compounds. J 
Nitrate of Silver. 
448 
Benzol. 
Sulphuric and Nitric 
Acids. 
448 
Bismiithi Citras, j 
Nitrate. 
Sulphuric Acid and Fer- 
rous Sulphate. 
286 
Bismuth, et Am- J 
Nitrate. 
Sulphuric Acid and Fer- 
man. Cit., ( 
rous Sulphate. 
286 
1 Insoluble salts. 
Dilute Nitric Acid. 
372 
Lead. 
Sulphuric Acid. 
211 
Copper. 
Silver. 
Excess of Ammonia. 
189 
Hydrochloric Acid. 
264 
Sulphate. 
Chloride of Barium. 
307 
Bismnthi Subcar- 
Nitrate of Silver. 
264 
Alkalies and a lk. 
'Evaporation after reinov- 
bonas, 
earths. 
Ammonia. 
Antimony, Arsenic, 
Tin. 
ing Bismuth. 
Fumes with Acetic Acid. 
Sulphuretted Hydrogen, 
254 
97 
254 
etc. 
Arsenic. 
Nascent Hydrogen and 
Nitrate of Silver. 
171 
Bismnthi Subni- j 
Carbonate. 
Nitric Acid. 
| 311 
tras, 1 
„ j 
Insoluble foreign salts. 
Chlorine (excess). 
Nitric Acid. 
Ammonia and Carbonate 
372 
Bromum, j 
1 of Barium. 
1 266 
Table of Tests—Continued. APPENDIX 
643 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Bromum, 
Iodine. 
Gelatinized Starch. 
2156 
Caffeina, 
Mineral matter. 
Incineration. 
100 
Bromate. 
Sulphuric Acid. 
268 
Iodide. 
Chlorine and mucilage of 
Starch. 
271 
Sulphate. 
Nitrate or Chloride of 
Caleii Bromidum, 
Barium. 
307 
Chloride. 
Nitrate of Silver, Carbo- 
nate of Ammonia, and 
Nitric Acid. 
271 
Magnesium. 
Phosphate of Sodium. 
122 
Magnesium. 
Phosphate of Sodium. 
122 
Cnlcii Carbonas 
Aluminium, Iron, or I 
Prseciip., 
Phosphate of Cal- > 
Amnionic Hydrate. 
371 
cium. J 
Aluminium, Iron, etc. 
Amnionic Hydrate. 
371 
Sulphate (of Calcium). 
Chloride or Nitrate of 
Cnlcii Chloridum, 
Barium. 
307 
Magnesium (more 
Phosphate of Sodium. 
122 
than trace). 
Insoluble Calcium 
Solution in water. 
370 
Salts. 
Cnlcii Hjpophos- 
ph in, 
Soluble Phosphate. 
Sulphate. 
Acetate of Lead. 
Chloride or Nitrate of 
211 
Barium. 
307 
Magnesium. 
Phosphate of Sodium. 
122 
Caleii Phosphas 
Carbonate (of Cal- 
Solution in Acids. 
311 
cium). 
Preecip., 
Aluminium. 
Boiling Caustic Potash. 
137 
Calx, 
Excess of Carbonate. 
Nitric Acid. 
311 
Silica. 
Nitric Acid. 
372 
Starch. 
Iodine. 
271 
Cumbojin, 
Bark, Sand, etc. 
Microscope after exhaus- 
Earthy Salts. 
tion with Spt. and water. 
Incineration with Mercu- 
403 
Cnrbo A nimatin 
ric Oxide. 
100 
Pnrificatu8, 
Phosphate (of Cal- 
Ammonia and Sulphate of 
cium). 
Magnesium. 
328 
Sulphurous Acid. 
Litmus-paper. 
94 
phidum, 
Sulphuretted Hydro- 
gen. 
Acetate of Lead. 
211 
Soap. 
Hydrochloric Acid. 
465 
Fats, Japan Wax, 
Soda and Hydrochloric 
Cera Alba, Cera 
Flava, 
Resin. 
Paraffin. 
Acid. 
Sulphuric Acid and dilu- 
465 
tion. 
465 
Didymium. 
Incineration. 
226 
Aluminium. 
Boiling in Caustic Potash, 
Chloride of Ammonium. 
226 
Cerii Oxnlae, 
Zinc. 
Caustic Potash and Sul- 
phide of Ammonium. 
226 
Carbonate(of Cerium). 
Hydrochloric Acid. 
311 
Metallic impurities. 
Sulphuretted Hydrogen. 
218 644 
APPENDIX. 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Cetacenm, 
Soft Fats. 
Melting-point. 
526 
Ghinoidinum, 
■ 
Alkaloidal Salts. 
Alkali to hot solution. 
388 
Mineral matter. 
Incineration. 
100 
Acids. 
Litmus. 
04 
Hydrochloric Acid. 
Nitrate of Silver. 
264 
Mineral matter. 
Incineration. 
100 
Other organic impur- 
Sulphuric Acid. 
445 
lty. 
Chloral, 
Alcoholate (of Ohio- 
Chloroform. 
445 
ral). 
Alcoholate (of Ohio- 
Boiling-point (above 97°). 
525 
ral). 
Alcoholate (of Ohio- 
Formation of Iodoform. 
429 
ral). 
Acids. 
Litmus. 
94 
Chlorides. 
Nitrate of Silver. 
264 
Chloroform urn. 
Pu- 
Free Chlorine. 
Iodide of Potassium. 
271 
rificatum, 
Aldehyd. 
Solution of Potash. 
430 
Hydrocarbons, etc. 
Sulphuric Acid; odor on 
evaporation. 
442 
Chlorides. 
Nitrate of Silver. 
264 
Chloroformum 
Ye- 
Much Hydrocarbons, 
Sulphuric Acid. 
442 
nale, 
etc. 
Non-volatile matter. 
Evaporation. 
100 
Chrysarobinnm, 
Mineral matter. 
Incineration. 
100 
More than traces of I 
Quinine or Quini- > 
Fluorescence of solution. 
3S7 
Cinchoniditue 
Sul- 
dine. J 
pitas, 
Organic impurity. 
Sulphuric Acid. 
442 
Sulphate of Ci.ncho- 
Quantitative Analysis. 
624 
nine. 
Quinine or Quinidine 
Fluorescence. 
387 
Cinchonina, 
(much). 
Organic impurity. 
Sulphuric Acid. 
442 
Coccus, 
Insoluble matter. 
Solution in cold water. 
370 
Codeina, 
Morphine. 
Nitric Acid. 
381 
r 
Fixed Oils. 
Evaporation of volatile 
Copaiba, 
Turpentine. 
oil. 
Odor when heated. 
480 
480 
Gurjun Balsam. 
Oxidation. 
480 
Carbolic Acid. 
Albumen. 
449 
Carbolic Acid. 
Ferric Chloride. 
449 
Creasotum, 
• 
Carbolic Acid. 
Glycerin. 
449 
Carbolic Acid. 
Dextro-rotation of polar- 
ized ray. 
449 
r 
Barium or Strontium. 
Sulphate of Calcium. 
254 
Greta Prrcparata, 
Magnesium. 
Iron. 
Phosphate of Sodium. 
Ferrocyanide of Potas- 
122 
sium. 
158 
r 
Lead or Iron. 
Sulphuretted Hydrogen in 
Cupri Acetas, 
Alkalies or alkaline 
alkaline solution. 
Evaporation after remov- 
189 
earths. 
ing Copper. 
189 APPENDIX. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Capri Sulphas, 
Foreign metals. 
Evaporation after remov- 
ing Copper. 
189 
Elaterinam, 
Alkaloids. 
Tannic Acid; Salts of 
Platinum or Mercury. 
Eel Ifovis Furiji- 
Mucus, crude Bile. 
Incomplete solubility in 
cat am, 
spirit. 
464 
Ferri Carbon as 
Saccharatus, 
Sulphate. 
General. 
Chloride or Nitrate of 
Barium. 
Quantitative Analysis. 
307 
577 
Zinc or Copper. 
Ammonia, then Sulphu- 
retted Hydrogen. 
133 
Alkalies. 
Evaporation and Inciner- 
ation after adding Am- 
monia. 
100 
Ferri Chloridum, 
Nitric Acid. 
Sulphate of Iron and Sul- 
phuric Acid. 
286 
Ferrous Salt. 
Ferrocyanide of Potas- 
siii in. 
158 
Oxychloride. 
Boiling with water (insol- 
uble). 
370 
Ferri Citrus, 
Fixed Alkalies. 
Litmus to residue on in- 
cineration. 
100 
Ferri et Ammonii 
Fixed Alkalies. 
Litmus to residue on in- 
Citrus, 
cineration. 
100 
Ferri et Ammonii 
Aluminium. 
Potassic Hydrate, then 
Sulphas, 
Chloride of Ammonium. 
137 
Ferri et Ammonii 
Fixed Alkalies. 
Litmus to residue on in- 
Tartras, 
cineration. 
100 
Ferri et Quinines 
r 
Fixed Alkalies. 
Litmus to residue on in- 
cineration. 
100 
Ultras, 
Ammonium Citrate. 
Heating with Potash. 
97 
Ferri et Strychni- ( 
Fixed Alkalies. 
Litmus to residue on in- 
ties Citrus, j 
cineration. 
100 
Ferri Ilupophos- 
Ferric Phosphate. 
Solubility in Acetic Acid. 
328 
phis, 
Calcium. 
Oxalate of Ammonium. 
113 
Ferri 1 o cl i clnm J 
Salts of Alkalies. 
Incineration and digestion 
100 
Saccharatnm, 1 
Free Iodine. 
Mucilage of Starch. 
271 
Ferri Lactus, 
Sulphate, Citrate, Tar- 
trate, etc. 
Acetate of Lead. 
211 
Ferri Sulphas, 
Copper, Ferric Salt. 
Sulphuretted Hydrogen f 
solution. ( 
157 
189 
Ferrum Reductum, 
Less than 80 per cent. 
Quantitative Analysis. 
592 
' 
Cane-sugar. 
Sulphuric Acid. 
454 
Sugars and Dextrin. 
Ignition on sand-bath. 
454 
Sugars. 
Potassio-cupric Tartrate. 
454 
Metallic Salts. 
Ignition. 
100 
Glycerinum, 
Acrylic Acid. 
Nitrate of Silver. 
454 
Hydrochloric Acid. 
Sulphuric Acid. 
Nitrate of Silver. 
Chloride or Nitrate of 
264 
Barium. 
307 
Oxalic Acid. 
Chloride of Calcium. 
314 
Iron Salts. 
Sulphide of Ammonium. 
157 
Table of Tests—Continued. APPENDIX. 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Glycerinum, 
Calcium Salts. 
Oxalate of Ammonium. 
113 
Gossypium, 
Acids or Alkalies. 
Litmus. 
94 
Hydrargyri Chlor. 
Gorros., 
' 
Arsenic. 
Nascent Hydrogen. 
171 
Mercuric Chloride. 
Sulphuretted Hydrogen. 
199 
11 ydrargyri Ghlor. 
Fixed soluble impuri- 
Residue on evaporating 
Mite, 
ties. 
aqueous solution. 
100 
Hydrargyri Gya- 
nidum, 
Ammoniated Mercury. 
Potash. 
97 
Mercuric Chloride. 
Iodide of Potassium. 
201 
Hydrargyri Iodi- 
Chloride or soluble 
Nitrate of Silver. 
264 
dum llubrum, 
Iodide. 
Hydrargyri Iodi- 
Mercuric Iodide. 
Solution in Alcohol and 
dum Viride, 
evaporation. 
193 
Hydrargyri Oxi- 
dum llubrum, 
Mercuric Nitrate. 
Strong heat. 
200 
Hydrargyri Sub- 
J 
Mercurous Salt. 
Solubility in Hydrochloric 
sulphas Flavus, 
1 
Arsenic, Antimony. 
Acid. 
Digestion with Potash and 
197 
addition of 1IC1. 
173 
Chromates, Iodides, 
Acetate of Lead to Potash 
Hydrargyri Sul- 
phidum llubrum, 
or foreign Sul- 
phides. 
solution. 
211 
Oxide of Mercury or 
Digest with diluted IINO3: 
Lead. 
pass Sulphuretted Hy- 
drogen. 
203 
Hydrargyrum, 
Foreign metals. 
Hyposulphite of Sodium. 
191 
' 
Mercurous Salt. 
Solubility in Hydrochloric 
Hydrargyrum Am- 
moniatum, 
Carbonate. 
Lead. 
Acid. 
Hydrochloric Acid. 
Sulphuric Acid to acetic 
311 
l 
solution. 
211 
Hyoscyaminse Sul- 
phas, 
Mineral matter. 
Incineration. 
100 
Ichthyovolla, 
Gelatin. 
Solubility in water. 
459 
' 
Alkali. 
Litmus. 
94 
Iodoformum, 
Iodide. 
Nitrate of Silver. 
271 
Mineral matter. 
Incineration. 
100 
. 
r 
Moisture. 
Solubility in Chloroform. 
269 
Chloride of Iodine. 
Solubility in water. 
269 
Iodum, 
Cyanide of Iodine. 
Formation of Prussian 
Blue. 
270 
Chlorine or Bromine. 
Nitrate of Silver. 
270 
. 
Deficiency of Citric 
Sp. gravity and Quantita- 
Limonis Succus, 
Acid. 
five Analysis. 
322 
Foreign Acids. 
General Analysis. 
322 
Linum, 
Deficiency of Oil. 
Extraction with Bisul- 
phide of Carbon. 
466 
Metals. 
Sulphuretted Hydrogen or 
Liq. Ammonii Ace- 
tatis, 
Empyreumatic sub- 
Sulphide of Ammonium. 
Odor when warmed, or 
218 
stances. 
Permanganate of Pot- 
ash. 
92 APPENDIX. 
647 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Liq. Ammonii Ace- 
Fixed saline matter. 
Incineration. 
100 
Liquor Calcis, 
Alkalies and alkaline 
Precipitation by CO2; test- 
Carbonates. 
Zinc or Copper. 
papers. 
Excess of Ammonia and 
94 
Sulphuretted Hydrogen. 
133 
Liq. Ferri Aceta- 
Fixed Alkalies. 
Excess of Ammonia, and 
tin, 
Ferrous Salt. 
incineration. 
Ferricvanide of Potas- 
157 
sium. 
157 
Zinc or Copper. 
Excess of Ammonia and 
Sulphuretted Hydrogen. 
133 
Fixed Alkalies. 
Excess of Ammonia, and 
Liq. Ferri Clilo- 
ridi, 
Nitric Acid. 
incineration. 
Sulphuric Acid and Fer- 
157 
Ferrous Salt. 
rous Sulphate. 
Ferricyanide of Potas- 
286 
sium. 
157 
Oxychloride. 
Solubility in water. 
146 
Liq. Ferri Citratis, 
Ammonium Citrate. 
Potash. 
97 
f 
Nitric Acid. 
Sirtphuric Acid and Fer- 
Liq. Ferri Subsul- 
rous Sulphate. 
286 
phatis, 
Ferrous Salts. 
Ferricyanide of Potas- 
sium. 
157 
Nitric Acid. 
Sulphuric Acid and Fer- 
Liq. Ferri Tersul- 
rous Sulphate. 
286 
phatis, 
Ferrous Salts. 
Ferricyanide of Potas- 
sium. 
157 
Liq. Hydraryyri J 
Nitratis, i 
Mercurous Salt. 
Hydrochloric Acid. 
204 
Liq. Peps ini, 
Mucus. 
Ammoniacal odor on keep- 
ing. 
461 
' 
Carbonate (of Potas- 
Hydrochloric or Acetic 
sium). 
Acid. 
311 
Alkaline earths. 
Carbonate of Sodium to 
Liquor Potassie, 
Sulphate. 
neutral solution. 
Chloride or Nitrate of 
106 
Barium. 
307 
Chloride. 
Nitrate of Silver. 
264 
Liq. Potassii Ci- 
( Vide Potassii Citras.) 
truths. 
Hydrochloric or Acetic 
Carbonate. 
Alkaline earths. 
Acid. 
Carbonate of Sodium to 
311 
Liquor Sodse, 
Sulphate. 
neutral solution. 
Chloride or Nitrate of 
106 
Barium. 
307 
Chloride. 
Nitrate of Silver. 
264 
Liq, Sodii Silica- f 
ilift. 1 
Much Alkali. 
Quantitative Analysis. 
560 
Liq. Zinci Ohio- 
(Vide Zinci Chlori- 
ridi. 
dum.) 
Lithii Bemoan, 
Salts of Alkalies. 
Alcohol and Ether. 
223 APPENDIX. 
Table of Tests— Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
f 
Salts of alkaline 
Oxalate of Ammonium. 
113 
earths. 
Lithii Benzoas, 
Metallic Salts. 
Sulphuretted Hydrogen. 
218 
Cinnamic Acid, etc. 
( Vide Acidum I’enzoi- 
cum.) 
637 
r 
Salts of Alkalies. 
Alcohol and Ether. 
223 
Lithii Bromidum, 
Salts of alkaline 
earths. 
Oxalate of Ammonium. 
113 
. 
Metallic Salts. 
Sulphuretted Hydrogen. 
218 
Lithii Carbonas, f 
Lithii Gitrns, •< 
Lithii Salicylas, 1 
( Vide Lithii Benzoas.) 
223 
Lupulinum, 
Sand, etc. 
Solubility in water. 
370 
r 
Pollen, Starch. 
Microscopical examina- 
Lycopodium, 
Sand, or more than 5 
tion. 
Incineration. 
403 
100 
per cent, of ash. 
Carbonate. 
Dilute Sulphuric Acid. 
118 
Magnesia, 
Chloride. 
Nitrate of Silver. 
264 
Magnesia Ponde- ■ 
Sulphate. 
Chloride of Barium. 
307 
708a, 
Calcium. 
Oxalate of Ammonium to 
acetic solution. 
113 
Aluminium or Cal- 
Carbonate and Chloride of 
cium. 
Ammonium. 
113 
Magnesii Carbo- 
Metals. 
Sulphydrate of Ammo- 
n as, 
nium and Ammonia. 
137 
Sulphate. 
Chloride of Barium. 
307 
Chloride. 
Nitrate of Silver. 
264 
Magnesii Citrus 
Tartrate. 
Acetate of Potassium and 
Gran., 
Metallic Salts. 
Acetic Acid. 
Sulphuretted Hydrogen or 
319 
Sulphide of Ammo- 
nium. 
218 
Magnesii Sulphas, - 
Alkaline earths. 
Carbonate, Chloride, and 
Hydrate of Ammonium. 
113 
Chloride. 
Alkaline Sulphates. 
Nitrate of Silver. 
Chloride of Barium, after 
264 
removing Magnesia. 
307 
Magnesii Sulphis, 
Sulphate of Magne- 
sium. 
Chloride of Barium. 
307 
Iron. 
Tannic Acid. 
354 
Mangani Sulphas, 
Copper. 
Alkalies or Magnesia. 
Sulphuretted Hydrogen. 
Ignition after removing 
218 
Manganese. 
229 
Manna, 
Insoluble matter. 
Digestion with Alcohol. 
Deficiency of Mannite. 
Quantitative Analysis. 
415 
Chlorides. 
Nitrate of Silver. 
264 
Sulphates. 
Chloride of Barium. 
307 
Starch. 
Iodine. 
271 
Mel, 
f 
Glucose, etc. 
Mixture with water and I 
Alcohol. 
Amountof ash on incin- j 
414 
1 
era tion. APPENDIX. 
649 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
r 
Other Alkaloids. 
Solubility in Sodic Hy- 
drate. 
Morpli ilia, 
-! 
Brucine, Strychnine, 
Sulphuric Acid, afterward 
etc. 
Bichromate. 
389 
1 
Mineral matter. 
Incineration. 
100 
Oleum *Etherenm, 
Acid (Sulpho-vinic). 
Litmus. 
94 
r 
Alcohol or Chloroform. 
Distillation at 80° C. 
440 
Oleum Amygdala 
Nitrobenzol. 
Nascent Hydrogen, and 
A marie, 
then Chlorate of Potas- 
si urn. 
417 
Oleum Amygdala 
Expre.su urn, 
I 
Foreign oils. 
Sulphuric Acid. 
466 
Oleum Gaultherise, 
1 
Chloroform or Alcohol. 
Distillation at 80° C. 
446 
1 
Oil of Sassafras. 
Nitric Acid. 
446 
Oleum Lavandula j 
Alcohol. 
Distillation at 80° C. 
446 
t Lornmy 
t 
Oleum Oliver, 
Foreign oils. 
General. 
466 
Oleum Sin ap is 
Volatile, 
l 
Disulphide of Carbon. 
Distillation at 50° C. 
310 
Paraffin, Wax, f 
Congelation-point after 
Oleum Theobroma, 
i 
j 
Stearin, Tallow, etc. 1 
melting. 
Melting-point not above 
465 
i 
l 
15° C. 
465 
Olea Destillata, 
f 
General. 
Solubility in Alcohol, sp. 
gravity, etc. 
542 
Opium, 
f 
i 
f 
Deficiency in Mor- 
phine. 
Quantitative Analysis. 
627 
Pepsinum Succha- 
Mucus. 
Turbidity of Hydrochloric 
ratum, 
i 
Acid solution. 
461 
r 
Fat or Resin. 
Odor on ignition. 
448 
Oils, Fats, or Resin. 
Sulphuric Acid to its 
Petrolatum, 
j 
1 
“ soap.” 
448 
I 
Other organic impur- 
Sulphuric Acid. 
448 
Phosphorus, 
l 
ities. 
Arsenic. 
Hydrosulphuric Acid to 
its Phosphoric Acid. 
Chloride of Barium to its 
327 
1 
Sulphur. 
l 
Phosphoric Acid. 
327 
Physostigmina Sa- 
lieylas, 
i 
1 
Mineral matter. 
Incineration. 
100 
f 
Mineral matter. 
Incineration. 
100 
Picrotoxinum, 
{ 
Alkaloids. 
Precipitated by Tannic 
Acid, Platinum Salts, 
[ 
etc. 
Pilocarpinse Hy- 
< 
Mineral matter. 
Incineration. 
100 
drochloras, 
l 
Piperina, 
Mineral matter. 
Incineration. 
100 
( 
Zinc, Alkalies, or alka- 
Precipitation by SHa, and 
Plumhi Acetas, 
] 
line earths. 
evaporation of filtrate. 
189 
( 
Copper. 
Excess of Ammonia. 
189 
f 
Zinc. 
Sulphydrate of Ammo- 
Plumbi Carbonas, 
1 
nium after removing 
Lead. 
133 650 
APPENDIX. 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
' 
Calcium (chalk). 
Oxalate of Ammonium 
after removing Lead. 
113 
Sulphate of Barium or 
Insolubility in Acetic f 
102 
Plumbi Carbonaa, 
211 
Silicates. 
Insolubility in Acetic 
Acid. 
351 
Alkaline Salts. 
Evaporation after remov- 
ing Lead. 
09 
Chromate (of Lead). 
Solubility in Chloride of 
Plumbi Iodidum, 
Zinc, etc. 
Ammonium. 
Evaporation after remov- 
211 
ing Lead. 
69 
Zinc, etc. 
Evaporation after remov- 
Plumbi Nitras, 
ing Lead. 
09 
Copper. 
Excess of Ammonia. 
189 
Carbonate. 
Dilute Acids. 
311 
Plumbi Oxidum, 
Zinc, etc. 
Organic matter. 
Evaporation after remov- 
ing Lead. 
Color of solution, and Per- 
09 
manganate of Potash. 
92 
Potassa, 
Chloride. 
Nitrate of Silver. 
264 
Sulphate. 
Chloride of Barium. 
307 
Carbonate. 
Effervescence with acids. 
311 
Silica. 
Solubility in Alcohol. 
06 
Pota8fta cum Calce, 
Silica. 
Solubility in Hydrochloric 
Acid. 
351 
Putassa Sulphurater, 
Deficiency of Sulphide. 
Sulphuretted Hydrogen. 
68 
Chloride. 
Nitrate of Silver. 
264 
Sulphate. 
Chloride of Barium. 
307 
Silica. 
Evap’n of acid solution, 
insolubility of residue. 
351 
Metals. 
Sulphuretted Hydrogen or 
Potasaii Acetas, 
Sulphide of Ammonium. 
218 
Alkaline earths. 
Carbonate of Sodium. 
106 
Carbonate. 
Effervescence with Acetic 
Acid. 
311 
Organic impurities. 
Sulphuric Acid. j 
297 
320 
r 
Sulphate. 
Chloride of Barium. 
307 
Potasaii Bicarbo- 
Chloride. 
Nitrate of Silver. 
264 
Carbonate. 
Chloride of Barium in the 
cold. 
364 
Potasaii Ilichromas, 
Sulphate. 
Chloride of Barium. 
307 
Sulphate. 
Chloride of Barium. 
307 
Chloride. 
Nitrate of Silver. 
264 
Metals. 
Sulphuretted Hydrogen or 
Potasaii Bitartras, 
Sulphide of Ammonium. 
218 
More than 6 per cent, 1 
of Tartrate of Cal- > 
Quantitative Analysis. 
u u 
316 
561 
cium. J 
Potassii Bromi- 
dum, 
Bromate. 
Iodide. 
Sulphuric Acid. 
Chlorine and mucilage of 
268 
Starch. 
271 APPENDIX. 
651 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Potassii Bromi- 
dtim, 
Sulphate. 
More than 3 per cent. 
Chloride of Barium. 
Quantitative Analysis. 
307 
569 
of Chloride. 
Silica, etc. 
Insolubility of residue on 
evaporation of acid 
Potassii Carbonas, - 
Alkaline earths. 
solution. 
Carbonate of Sodium. 
351 
106 
Chloride. 
Nitrate of Silver. 
264 
Sulphate. 
Chloride of Barium. 
307 
Sulphate. 
Chloride of Barium. 
307 
Potassii Chloras, 
Chloride. 
Nitrate of Silver. 
264 
Calcium. 
Oxalate of Ammonium. 
113 
Carbonate. 
Effervescence with acids. 
311 
Potassii Citr(l8, 
Sulphate. 
Chloride. 
Chloride of Barium. 
Nitrate of Silver. 
307 
264 
Tartrate. 
Acetic Acid. 
319 
Potassii Cyanidum, 
Carbonate. 
Effervescence with Acids. 
311 
Potassii el Sodii J 
Calcium. 
Sulphate. 
Oxalate of Ammonium. 
Chloride of Barium. 
113 
307 
Chloride. 
Nitrate of Silver. 
264 
Potassii Ferrocy- I 
anidum, 
Carbonate. 
Sulphate. 
Chloride. 
Effervescence with Acids. 
Chloride of Barium. 
Nitrate of Silver. 
311 
307 
264 
r 
Carbonate. 
Effervescence with Acids. 
311 
Potassii Hypo- 
Sulphate. 
Chloride of Barium. 
307 
phosphis, 
Phosphate. 
Magnesia mixture. 
328 
Calcium. 
Oxalate of Ammonium. 
113 
f 
lodate. 
Mucilage of Starch and 
Tartaric Acid. 
75 
Potassii Iodidum, 
Chloride or Bromide. 
Ammonia, Nitrate of Sil- 
ver, and Nitric Acid. 
271 
Sulphate. 
Chloride of Barium. 
307 
Metals. 
Sulphuretted Hydrogen or 
Sulphide of Ammonium. 
218 
Alkaline earths. | 
102 
Potassii Niiras, 
nium. J 
113 
119 
Sulphate. 
Chloride of Barium. 
307 
Chloride (of Sodium). 
Nitrate of Silver. 
264 
Nitrate. 
Sulphuric Acid and Fer- 
rous Sulphate to decol- 
orized solution. 
286 
Potassii Perm an- 
Chloride. 
Nitrate of Silver to decol- 
you a ft. 
Sulphate. 
orized solution. 
Nitrate of Barium after 
264 
removing Manganese 
by Ammonia. 
307 
\ 
Alkaline earths. 
Carbonate or Phosphate 
of Ammonium. 
122 
Potassii Sulphas, 
Metals. 
Sulphuretted Hydrogen or 
Sulphide of Ammonium. 
218 
Chloride. 
Nitrate of Silver. 
264 
Potassii Snlphis, 
Sulphate. 
Chloride of Barium. 
307 APPENDIX. 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
f 
Calcium. 
Oxalate of Ammonium. 
113 
Potass li Tartraa, ■< 
Sulphate. 
Chloride of Barium. 
307 
l 
Chloride. 
Nitrate of Silver. 
2(54 
Organic impurities. 
Sulphuric Acid. 
386 
<Juinidinee Sul- 
phas, 
Morphine. 
Nitric Acid. 
381 
Cinchonine, Quinine, 
Iodide of Potassium and 
or Cinchonidine. 
Ammonic Hydrate. 
387 
Organic impurities. 
Sulphuric Acid. 
386 
Quinina, 
Cinchonine, Cincho- 4 
nidine, or Quini- > 
dine. J 
Sulphate of Ammonium 
and Ammonia. 
624 
Organic impurities. 
Sulphuric Acid. 
386 
Free water. 
Drying upon water-batli. 
624 
Quininte liisul- 
Sulphates of Quini-1 
phas, 
dine, Cinchoni- ! 
dine, or Cincho- j 
Ammonia, as for Quinine. 
624 
nine. 
Organic impurities. 
Sulphuric Acid. 
386 
Quin hue Hydro- 
bromas, 
Free water. 
Sulphate. 
Barium. 
Drying upon water-bath. 
Chloride of Barium. 
Sulphuric Acid. 
385 
307 
102 
Cinchonine, etc. 
Ammonia, as for Quinine. 
624 
Quininse Hydro- 
chloras, 
r 
Organic impurities. 
Barium. 
Sulphuric Acid. 
Sulphuric Acid. 
386 
102 
Sulphate. 
Chloride of Barium. 
307 
Organic impurities. 
Sulphuric Acid. 
386 
Ammonia (Sulphate). 
Boiling with milk of lime. 
97 
Quininse Sulphas, 
Free water. 
Drying on water-bath. 
624 
Cinchonine Sulphate, 
Ammonium Hydrate. 
624 
etc. 
Quininse Valeri- 
■ 
Organic impurities. 
Sulphuric Acid. 
386 
an as, 
Sulphate. 
Chloride of Barium. 
307 
like uni, 
Turmeric. 
Boracic Acid. 
331 
r 
Insoluble salts, etc. 
Aqueous or alcoholic solu- 
Sacchamm, 
Grape-Sugar or In- 
tion on standing. 
Nitrate of Silver and Am- 
verted Sugar. 
monic Hydrate. 
412 
Sacchamm Lac- j 
tis, ( 
Cane-Sugar. 
Sulphuric Acid. 
413 
Saiicinnm, 
Mineral matter. 
Incineration. 
100 
Santoninum, 
Mineral matter. 
Incineration. 
100 
More than 34 per cent. 
Drying at 110° C. 
610 
of water. 
Animal Fats. 
Gelatinization of 4 per 
Sap of 
cent, alcoholic solution. 
463 
Carbonate of Sodium. 
Solubility in alcohol. 
463 
Silica and insoluble 
Solubility in water. 
463 
matter. 
Metals. 
Sulphuretted Hydrogen. 
218 
More than 4 per cent. 
Drying at 100° C. 
610 
Sapo Viridls, 
of water. 
Free Fats. 
Digestion of dried soap in 
Benzol. 
463 APPENDIX. 
653 
Table of Tests—Continued. 
Name of Preparation. 
Iinpu rities. 
Tests. 
Page. 
f 
Insoluble Carbonates. 
Dilute Acids to residue 
from alcohol and water. 
311 
&apo v trims, 
Starch. 
Iodine to residue from 
alcohol and water. 
271 
SenmmoHi'um, 
Chalk. 
Effervescence with Acids. 
311 
Starch. 
Iodine. 
271 
Kesin of Guaiacum. 
Inner surface of potato- 
Scammonii Resina, 
paring. 
421 
Resin of Jalap. 
Insolubility in Ether. 
421 
Organic matter. 
Color of aqueous solution : 
Sulphuric Acid. 
Soda, 
Chloride. 
Nitrate of Silver. 
264 
Sulphate. 
Chloride of Barium. 
307 
Carbonate. 
Etfervescence with Acids. 
311 
Silica or Carbonate. 
Solubility in Alcohol. 
67 
r 
Chloride. 
Nitrate of Silver. 
264 
Sulphate. 
Silica. 
Chloride of Barium. 
Insolubility of residue on 
307 
evaporating acid solu- 
tion. 
351 
Sodii Acetas, 
Metals. 
Sulphuretted Hydrogen or 
Sulphide of Ammonium. 
218 
Alkaline earths. 
Carbonate of Sodium. 
106 
Carbonate. 
Effervescence with Acids. 
311 
Organic impurities. 
Sulphuric Acid. j 
297 
320 
Arsenite. 
Sulphuretted Hydrogen 
water. 
172 
Sodii Arsenias, 
Excess or deficiency "I 
1 
of water of crys- >■ 
Quantitative Analysis. 
610 
' l 
tallization. j 
Sodii Benzoas, 
( Vide Acidum Benzoi- 
cum.) 
03/ 
Chloride. 
Nitrate of Silver. 
264 
Sulphate. 
Chloride of Barium. 
307 
Ammonium Salts. 
Boiling with solution of 
Sodii Bicarbonas, 
Carbonate. 
Soda. 
Chloride of Barium in I 
97 
364 
560 
the cold, and Quanti- > 
tative Analysis. j 
Sodii Bisu/phis, 
Sulphate. 
Chloride of Barium. 
307 
r 
Carbonate. 
Effervescence with Acids. 
311 
Chloride. 
Nitrate of Silver. 
264 
Sodii Boras, 
Sulphate. 
Chloride of Barium. 
307 
Alkaline earths. 
Carbonate of Sodium. 
106 
Metals. 
Hydrosulphuric Acid. 
218 
Brornate. 
Sulphuric Acid. 
268 
Iodide. 
Chlorine-water and muci- 
Sodii Bromidum, 
Sulphate. 
lage of Starch. 
Chloride of Barium. 
271 
307 
More than 3 per cent. 
Quantitative Analysis. 
570 
of Chloride. 
Sodii Carbonas, 
Chloride. 
Nitrate of Silver. 
264 654 
APPENDIX. 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Sulphate. 
Chloride of Barium. 
307 
Sodii Carbonag. 
Metals. 
Hydrosulphuric Acid. 
218 
Alumina. 
Ammonia and Chloride of 
Ammonium. 
137 
Potassium. 
Bitartrate of Sodium. 
78 
Sodii Chloras, 
■ 
Calcium. 
Chloride. 
Oxalate of Ammonium. 
Nitrate of Silver. 
113 
264 
Sulphate. 
Chloride of Barium. 
307 
Metals. 
Hydrosulphuric Acid or 
Sulphide of Ammonium. 
218 
Alkaline earths. 
Carbonate of Sodium. 
103 
Sodii Chloridum, 
Sulphate. 
Chloride of Barium. 
307 
Iodide or Bromide. 
Chlorine-water and Starch 
to residue on evaporat- 
ing alcoholic solution. 
268 
f 
Calcium. 
Oxalate of Ammonium. 
113 
Potassium. 
Bitartrate of Sodium. 
78 
Soda Hifpophos- 
Carbonate. 
Effervescence with Acids. 
311 
pkig, 
Sulphate. 
Chloride of Barium. 
307 
Phosphate. 
Ammonia and Sulphate of 
Magnesium. 
328 
Sodii Hi/posul 
Sulphate. 
Chloride of Barium. 
307 
phig, 
Carbonate. 
Effervescence with Acids. 
311 
Iodate. 
Mucilage of Starch and 
Tartaric Acid. 
75 
Sodii lodidum, 
Sulphate. 
Chloride of Barium. 
307 
Chloride or Bromide. 
Ammonia, Nitrate of Sil- 
ver, and Nitric Acid. 
271 
f 
Metals. 
Sulphuretted Hydrogen or 
Sulphide of Ammonium. 
218 
Alkaline earths. 
Carbonate of Ammonium. 
113 
Sodii Nitrag, 
1 
Potassium. 
Sulphate. 
Bitartrate of Sodium. 
Chloride of Barium. 
78 
307 
Chloride. 
Nitrate of Silver. 
264 
Iodide. 
Chlorine-water and Muci- 
lage of Starch. 
271 
Carbonate. 
Effervescence with Acids. 
311 
Sulphate. 
Chloride of Barium. 
307 
Sodii Phogphcig, 
• 
Chloride. 
Nitrate of Silver. 
264 
Metals. 
Sulphuretted Hydrogen or 
l 
Sulphide of Ammonium. 
218 
Carbonate. 
Effervescence with Acids. 
311 
Sodii Pyrophos- 
phag, 
Sulphate. 
Chloride of Barium. 
307 
Chloride. 
Nitrate of Silver. 
264 
Metals. 
Sulphuretted Hydrogen or 
Sulphide of Ammonium. 
218 
Carbonate, 
Effervescence with Acids. 
311 
Sodii Salicylag, 
' 
Sulphate, 
Chloride. 
Chloride of Barium. 
Nitrate of Silver. 
307 
264 
Organic impurities. 
Sulphuric Acid. 
334 
Alkaline earths. 
Carbonate of Sodium. 
JO0 
Sodii Santonincig, 
Alkaloids. 
Precipitate with Tannic 
or Picric Acid. APPENDIX. 
655 
Table of Tests—Continued. 
Name of Preparation 
Impurities. 
Tests. 
Page 
C 
Carbonate. 
Effervescence with Acids. 
311 
Chloride. 
Nitrate of Silver. 
264 
Sodii Sulphax, •! 
Metals. 
Ilydrosulphuric Acid or 
Sulphide of Ammonium. 
218 
Ammonium Sulphate. 
Boiling with Soda. 
97 
Sodii Sulphis, 
Sulphate. 
Chloride of Barium. 
307 
Sodii Sulphocar- ( 
bolax, | 
Sulphate. 
Chloride of Barium. 
307 
r 
Deficiency of Nitrite 
Quantitative Analysis. 
435 
Spiritus jEthen's j 
Nitroxi, 
1 of Ethyl. 
Free Acid. 
Effervescence with Bicar- 
bonate of Sodium. 
311 
l 
General. 
Specific gravity. 
544 
' 
Empyreumatic sub- 
Neutralization with Sul- 
stances. 
phuric Acid and odor, 
and Permanganate of 
Potassium. 
92 
Spiritus Ammonite, -[ 
Carbonate. 
Effervescence with Acids. 
311 
Sulphate. 
Chloride of Barium. 
307 
Chloride. 
Nitrate of Silver. 
264 
| Calcium. 
Oxalate of Ammonium. 
113 
Metals. 
Sulphuretted Hydrogen or 
i 
Sulphide of Ammonium. 
218 
Fusel Oil. 
Odor on evaporation. 
431 
More than .25 per cent. 
Drying at 100° C. 
610 
of solids. 
Spiritux Frumenti, \ 
Sugar, Glycerin, or 
Characters of solids on 
spices. 
evaporation. 
Excess of Acid. 
Quantitative Analysis. 
564 
Deficiency in alcohol. 
Specific gravity. 
542 
Fusel Oil. 
Odor on evaporation. 
431 
Amyl Alcohol. 
Sulphuric Acid. 
431 
Spiritus Vini Gal- 
Methyl Alcohol, Al- 
dehyd, or Oak Tan- 
Solution of Potassa. 
431 
nin. 
Methyl Alcohol. 
Permanganate of Potas- 
si urn. 
431 
Strychnin a, 
Brucine. 
Nitric Acid. 
390 
Sulphuric Iodi- j 
dum, ( 
Mineral matter. 
Incineration. 
100 
r 
Free Acid. 
Litmus. 
94 
Sulphur Lotum, 
[Arsenious Sulphide. 
Wash with Ammonia: 
evaporate to dryness. 
172 
Arsenious Acid. 
Ilydrosulphuric Acid. 
172 
Free Acid. 
Litmus. 
94 
Sulphate of Calcium. | 
Chloride of Barium. 
Carbonate of Ammonium 
307 
Sulphur Priecipi- 
t at uni, 
and Ammonia. 
113 
Alkalies. 
Solubility in water. 
370 
Alkaline earths. 
Solution in Hydrochloric 
Acid, and evaporation. 
370 
Arsenious Sulphide. 
Amnionic Hydrate. 
172 
J Arsenious Acid. 
Ilydrosulphuric Acid. 
172 APPENDIX. 
Table of Tests—Continued. 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Sulphur Sublima- 
tum, 
Earthy matter. 
Incineration. 
100 
Free Iodine. 
Mucilage of Starch. 
271 
Syrupus Acidi Hu- 
Sulphuric Acid. 
Chloride of Barium. 
307 
driodici, 
Hydrochloric Acid. 
Nitrate of Silver and Am- 
monia. 
2G4 
Syrupus F e r r i 
Bvomidi, 
Free Bromine. 
Mucilage of Starch. 
268 
Syrupus Ferri Io- f 
didi, ( 
Tamarindus, 
Free Iodine. 
Mucilage of Starch. 
271 
Traces of Copper. 
Iron. 
189 
Thymol, 
Carbolic Acid. 
Ferric Chloride to satura- 
Zinc and Copper. 
ted aqueous solution. 
Ilydrosulphuric Acid, af- 
449 
ter removing Iron. 
218 
Tinetura Ferri 
Fixed Alkalies. 
Evaporation and ignition, 
Acet., 
Ferrous Salt. 
after removing Iron. 
Ferricyanide of Potas- 
100 
siu in. 
157 
Zinc or Copper. 
Ilydrosulphuric Acid, af- 
ter removing Iron. 
218 
Fixed Alkalies. 
Evaporation and ignition. 
Tinetura Ferri 
after removing Iron. 
100 
Chloridiy 
Nitric Acid. 
Sulphuric Acid and F"er- 
Ferrous Salt. 
rous Sulphate. 
Ferricyanide of Potas- 
286 
sium. 
157 
Oxychloride. 
Dilution with water, and 
boiling. 
146 
Veratrina, 
Mineral matter. 
Incineration. 
100 
Tannic Acid. 
Ferric Chloride. 
355 
Excess or deficiency of 
Quantitative Analysis. 
632 
Vinum Album, 
Alcohol. 
Excess or deficiency of 
Quantitative Analysis. 
566 
Acid. 
Vinum Album 
. 
Excess or deficiency of 
Quantitative Analysis. 
632 
Fortius, 
Alcohol. 
Excess or deficiency of 
Quantitative Analysis. 
632 
Alcohol. 
Excess or deficiency of 
Quantitative Analysis. 
566 
Vinum liubrum, 
Acid. 
Aniline colors. 
Ammonia, Ether; evap- 
oration of ethereal solu- 
tion in contact with silk. 
487 
Lead or Copper. 
Ilydrosulphuric Acid. 
218 
Iron, Aluminium, 
or 
Carbonate of Ammonium 
alkaline earths. 
in excess. 
133 
Zinci Acetas, 
Salts of Alkalies 
or 
Removal of Zinc: evap- 
alkaline earths. 
oration and ignition of 
filtrate. 
133 
Lead or Copper. 
Ilydrosulphuric Acid. 
218 
Zinci Bromidum, 
Iron, Aluminium, 
or 
Carbonate of Ammonium 
alkaline earths. 
in excess. 
133 APPENDIX. 
65 7 
Name of Preparation. 
Impurities. 
Tests. 
Page. 
Zinci Bromidum, 
Alkalies or alkaline 
earths. 
Evaporation and ignition, 
after removing Zinc. 
133 
Lead or Copper. 
Hydrosulphuric Acid. 
218 
Zinci Carbonas 
Prsecipitatvs, 
Iron, Aluminium, or 
alkaline earths. 
Carbonate of Ammonium 
in excess. 
133 
Salts of Alkalies or 
Evaporation and ignition, 
alkaline earths. 
after removing Zinc. 
133 
Basic Chloride. 
Alcohol to aqueous solu- 
tion. 
131 
Lead or Copper. 
Hydrosulphuric Acid. 
218 
Zinci Chloridum, 
Iron, etc. 
Carbonate of Ammonium 
in excess. 
133 
Alkalies or alkaline 
Evaporation and ignition, 
earths. 
after removing Zinc. 
133 
Zinci lodidnm, 
Zinci Oxiclnm, 
Same as other Zinc 
Salts. 
Zinci Phosphidnm, 
Lead or Copper. 
Hydrosulphuric Acid. 
218 
Chloride. 
Same as other Zinc 
Nitrate of Silver. 
264 
Zinci Sulpha#, 
Salts. 
Alkalies or alkaline 
Evaporation and ignition. 
Zinci Valerianas, < 
earths. 
after removing Zinc. 
133 
1 
Butyrate of Zinc. 
Acetate of Copper. 
359 
f 
Arsenic. 
Nascent Hydrogen and 
Zineum, -( 
Nitrate of Silver. 
171 
1 
Lead, Iron, or Copper. 
Excess of Ammonia. 
133 
Table of Tests— Continued. APPENDIX. 
Equivalent Weights of Citric Acid, Tartaric Acid, Carbonate of Potassium, Bicarbonate of Potassium, Carbonate of Sodium, 
Bicarbonate of Sodium, Carbonate of Ammonium, and Carbonate of Magnesium, repeated (in black) for 20 parts of 
each, and incidentally (in Roman) for other proportions. (Exact to two places of decimals.) 
Citric Acid (HsCfiHsCh.HUO) + 3X2 = 140 
20.00 
18.66 
16.96 
14.00 
9.78 
16.66 
23.72 
29.31 
Tartaric Acid H2C4H4O6 — 150 
21.43 
20.00 
18.26 
15.00 
10.49 
17.85 
25.42 
31.41 
Carbonate of Potassium K2CO3 + 16 % Aq. — 164.285 
23.47 
21.90 
20.00 
16.43 
11.48 
19.52 
27.87 
34.40 
Bicarbonate of Potassium 2(KHCC>3) — 200 
28.57 
26.66 
24.34 
20.00 
13.98 
23.81 
33.89 
41.90 
Carbonate of Sodium NaiCOsAbHiO — 286 
40.08 
38.13 
34.81 
28.60 
20.00 
34.04 
48.47 
59.98 
Bicarbonate of Sodium 2(NaHCC>3) — 168 
24.00 
22.40 
20.45 
16.80 
11.74 
20.00 
28.47 
35.18 
Carbonate of Ammonium (N4H16C3O8) +- 2— 118 
16.85 
15.73 
14.36 
11.80 
8.25 
14.04 
20.00 
24.71 
Carb. of Magnes. ((MgC03)s,Mg2H0,4H20) + 4 = 95.5 
13.64 
12.73 
11.62 
9.55 
6.68 
11.37 
16.18 
20.00 
The amount of acid given in any column will satui-ate the amount of carbonate in the same column, and vice versa. 
The amounts of carbonate in any column are equal to each other in chemical power. 
Lemon-juice (sp. gr. 1.039) contains, on an average, 7 per cent, by weight of citric acid. 
The same Table in Round Numbers, for Purposes of Prescribing and Dispensing. 
(The old names in Latin.) 
Citric Acid 
20 
19 
17 
14 
10 
17 
24 
30 
Tartaric Acid 
22 
20 
18 
15 
11 
18 
26 
32 
Carbonate of Potassium (Potass® Carbonas) 
24 
22 
20 
16 
12 
20 
28 
35 
Bicarbonate of Potassium (Potass® Bicarbonas) 
29 
27 
24 
20 
14 
24 
34 
42 
Carbonate of Sodium (cryst.) (Sod® Carbonas) 
40 
S8 
35 
28 
20 
34 
49 
60 
Bicarbonate of Sodium (Sod® Bicarbonas) 
24 
22 
20 
17 
12 
20 
29 
36 
Carbonate of Ammonium (Ammoni® Carbonas) 
17 
16 
14 
12 
8 
14 
20 
25 
Carbonate of Magnesium (Magnesi® Carbonas) 
13 
13 
11 
9 
7 
11 
16 
20 
The Table is read thus: 20 grains of Citric Acid will saturate 29 grains of Bicarbonate of Potassium; 20 grains of Bicar- 
bonate of Sodium will saturate, or be saturated by, 18 grains of Tartaric Acid; 11 grains of Tartaric Acid = 8 grains of 
Carbonate of Ammonium ; 20 grains of Bicarbonate of Sodium are equivalent to, or will do as much work as, 34 grains of 
Carbonate of Sodium; 14 grains of Citric Acid are as strong as 15 of Tartaric Acid. It is occasionally convenient to double 
the numbers, halve them, or take some other proportion ; also to employ them in weights other than grains. 
Lemon-juice contains, on an average, 32 i grains of citric acid in 1 fluidounce, or 4 grains per fluidrachm. ' 
Saturation Tables. APPENDIX. 
659 
The Proportion by Weight of Absolute or Real Alcohol (C2II:)IIO) in 
100 Parts of Spirits of Different Specific Gravities (Foicnes). 
S|>. gr. at 60° 
(15°.o C.). 
Per- 
centage 
Sp. gr. at 60° 
Per- 
centage 
Sp. gr. at 60° 
Per- 
centage 
of real 
(15°.5 0.). 
of real 
(15°. 5 C.). 
of real 
0.9991 ... 
alcohol. 
... 0.5 
0.9511 ... 
alcohol. 
... 34 
0.8769 ... 
alcohol. 
... 68 
0.9981 ... 
... 1 
0.9490 ... 
0.8745 ... 
... 69 
0.9965 ... 
... 2 
0.9470 ... 
... 36 
0.8721 ... 
... 70 
0.9947 ... 
... 3 
0.9452 ... 
... 37 
0.8696 .. 
... 71 
0.9930 ... 
.. 4 
0.9434 ... 
... 38 
0.8672 .., 
... 72 
0.9914 ... 
... 5 
0.9416 ... 
... 39 
0.8649 ... 
... 73 
0.9898 ... 
... 6 
0.9396 ... 
... 40 
0.8625 ... 
... 74 
0.9884 ... 
... 7 
0.9376 ... 
... 41 
0.8603 ... 
... 75 
0.9869 ... 
... 8 
0.9356 ... 
... 42 
0.8581 ... 
... 76 
0.9855 ... 
... 9 
0.9335 ... 
... 43 
0.8557 ... 
... 77 
0.9841 ... 
.. 10 
0.9314 ... 
... 44 
0.8533 ... 
... 78 
0.9828 ... 
... 11 
0.9292 ... 
0.8508 ... 
... 79 
0.9815 ... 
... 12 
0.9270 ... 
... 46 
0.8483 ... 
... 80 
0.9802 ... 
.. 13 
0.9249 ... 
... 47 
0.8459 ... 
... 81 
0.9789 ... 
... 14 
0.9228 ... 
... 48 
0.8434 ... 
... 82 
0.9778 ... 
.. 15 
0.9206 ... 
... 49 
0.8408 ... 
... 83 
0.9766 ... 
... 16 
0.9184 ... 
... 50 
0.8382 ... 
... 84 
0.9753 ... 
.. 17 
0.9160 ... 
.. 51 
0.8357 ... 
... 85 
0.9741 ... 
.. 18 
0.9135 ... 
... 52 
0.8331 ... 
... 86 
0.9728 ... 
... 19 
0.9113 ... 
... 53 
0.8305 .. 
... 87 
0.9716 ... 
.. 20 
0.9090 ... 
... 54 
0.8279 ... 
... 88 
0.9704 ... 
... 21 
0.9069 ... 
... 55 
0.8254 ... 
... 89 
0.9691 ... 
... 22 
0.9047 ... 
... 56 
0.8228 ... 
... 90 
0.9678 ... 
... 23 
0.9025 ... 
... 57 
0.8199 ... 
... 91 
0.9665 ... 
.. 24 
0.9001 ... 
... 58 
0.8172 ... 
... 92 
0.9652 ... 
... 25 
0.8979 ... 
... 59 
0.8145 ... 
... 93 
0.9638 ... 
... 26 
0.8956 ... 
... 60 
0.8118 ... 
... 94 
0.9623 ... 
... 27 
0.8932 ... 
... 61 
0.8089 ... 
... 95 
0.9609 ... 
... 28 
0.8908 ... 
... 62 
0.8061 ... 
... 96 
0.9593 ... 
.. 29 
0.8886 ... 
... 63 
0.8031 ... 
... 97 
0.9578 ... 
... 30 
0.8863 ... 
... 64 
0.8001 ... 
... 98 
0.9560 ... 
... 31 
0.8840 ... 
... 65 
0.7969 ... 
... 99 
0.9544 ... 
... 32 
0.8816 ... 
... 66 
0.7938 ... 
... 100 
0.9528 ... 
... 33 
0.8793 ... 
... 67 APPENDIX. 
Symbols and atomic 
value. 
Atomic 
weight. 
Aluminium (A12VI) 
Al1 
27 
Antimony (Sbm) 
Sbv 
120 
Arsenicum (As111) 
Asv 
74.0 
Barium .... 
Ba11 
136.8 
Beryllium (Glucinum) 
Be" 
9 
Bismuth (Bi111) . 
Biv 
210 
Boron .... 
Bin 
11 
Bromine (79-75, Stas) 
Br1 
79.8 
Cadmium .... 
Cd111 
111.8 
Caesium .... 
Csl 
132.6 
Calcium .... 
Ca11 
40 
Carbon (C11) 
CIV 
12 
Cerium (Ce111) (,88’ Men3el^ff) . 
CeVI 
141 
Chlorine (35-3fi8'Stas) 
Cl1 
35.4 
Chromium (Cr2VI) 
CrVI 
52.4 
Cobalt (Co11) 
CoVI 
58.9 
Copper .... 
Davyum ? 
Cu11 
63.2 
Decipium ? ... 
I)pn 
Didymium (*“■ 
D” 
144.6 
Erbium ? (171, MendeIejeff) 
Eb11 
165.9 
Fluorine .... 
F1 
19 
Gallium .... 
Glucinum. Bee Beryllium. 
GaIV 
68.8 
Gold (Au1) .... 
Au111 
196.2 
Hydrogen .... 
IF 
1 
Ilmenium ? . 
IF 
Indium (113-MenW) . 
InVI 
56.7 
Iodine Stas) 
I1 
126.6 
Iridium .... 
IrIV 
192.7 
Iron (Fe11 & Fe2VI) 
FeVI 
55.9 
Lanthanum (138, Meudel(yefr) 
Lavoisium ? 
La11 
138.5 
Lead (nPbu) 
PbIV 
206.5 
Lithium (»•<>«. s*") 
L1 
7 
Magnesium 
Mg11 
24 
Manganese (Mn11 A MnIV) . 
MnVI 
54 
Mercury .... 
Hg11 
199.7 
Molybdenum 
Mosandrum. 
MoVI 
95.5 
Neptuniuiii .... 
Npv 
THE ELEMENTS. APPENDIX. 
661 
Symbols and atomic 
Atomic 
value. 
weight. 
Nickel (Ni11) 
NiVI 
58 
Niobium 
Nbv 
94 
Nitrogen (N1 & Nni) (14009>Staa) 
Nv 
14 
Norwegium. 
Osmium 
OsTV 
99.5 
Oxygen (15-96, Stas) 
Ou 
16 
Palladium . 
PdIV 
105.7 
Philippium ? 
Pp11 
Phosphorus (PIH) 
pv 
31 
Platinum Andrew9) . 
PtIV 
194.4 
Potassium (39 04, Staa) 
K1 
39 
Rhodium 
RhIV 
104.1 
Rubidium 
Rb1 
85.3 
Ruthenium 
RuIV 
104.2 
Scandium. 
Selenium or Selenion . 
SeVI 
78.8 
Silicon 
SiIV 
28 
Silver staS 
■W 
107.7 
Sodium (22-98’Stas) ‘ ‘ 
Na1 
23 
Strontium 
Sr11 
87.4 
Sulphur (Sn & SIV) . 
SVI 
32 
Tantalum 
Tav 
182 
Tellurium 
TeVI 
128 
Terbium ? . 
Tb'1 
Thallium (**• CrookC3) . 
Tpn 
203.7 
Thorinum or Thorium 
Th11 
233 
Tin (Sn11) . 
SnIV 
117.7 
Titanium 
TiIV 
48 
Tungsten 
WVI 
183.6 
Uralium (,87-25> Guyard ) 
Uranium (24°- . 
Tjvi 
238.5 
Vanadium . 
yv 
51.3 
Ytterbium? 
Yb 
172.7 
1*1 mu 
yn 
89.8 
Zinc .... 
Zn11 
64.9 
Zirconium . 
ZiIV 
90 
The quanlivalence or atomic value of some elements is, apparently, 
variable; in the above Table the full coefficients are given in the 
column of symbols, other common values in parentheses. 
Atomic, weights are sometimes obscurely termed equivalents. INDEX. 
Abies balsamea, 481. 
canadensis, 481. 
excelsa, 478. 
Abrus precatorius, 421. 
Absinthium, 472. 
Absinthol, 472. 
Absolute alcohol, 428, 525. 
Abstracts, 517. 
Acacia catechu, 355. 
Acacia suma, 355. 
Acacice gummi, 112. 
impurities in, 637. 
Acetate of ammonium, solution of, 
91. 
amyl, 446. 
copper, 189. 
ethyl, 296, 436. 
iron, 147. 
lead, 207. 
morphine, 380. 
potassium, 68. 
sodium, 82. 
zinc, 131. 
Acetates, 294. 
analytical reactions of, 297. 
decomposition of aqueous so- 
lution of, 295. 
volumetric estimation of, 566. 
Acetic acid, 295, 468. 
ether, 297, 436. 
glacial, 296, 526. 
volumetric estimation of free, 
566. 
Acetone, 297. 
Acetonitrate of barium, 124. 
of iron, 154. 
Acetum, 295. 
cantharidis, 295. 
colchici, 295. 
lobelias, 295. 
opii, 295. 
sanguinarice, 295. 
scilicc, 295. 
Acetyl, 295. 
Acid, acetic, 295, 468, 637. 
glacial, 296, 526. 
aconitic, 322. 
acrylic, 454. 
amyric, 480. 
anemonic, 332. 
angelic, 471. 
arabic, 407. 
arachidic, 468. 
arsenic, 165. 
arsenious, 164. 
benzoic, 332, 472, 637. 
benzol-disulphonic, 450. 
boracic, 330, 637. 
bromic, 293. 
butyric, 360, 468. 
camphoretic, 476. 
camphoric, 476. 
cantharidic. 477. 
caproic, 468. 
caprylic, 468. 
carbazotic, 450. 
carbolic, 449, 525, 637. 
carbolic, impure, 449. 
carbonic, 30, 309. 
carminic, 334. 
catechuic, 355. 
cathartic, 417. 
cathartogenic, 418. 
cerotic, 468. 
cetraric, 334. 
chavicic, 398. 
chelidonic, 394. 
chloric, 289, 291. 
cholalic, 464. 
chromic, 235, 637. 
chrysammic, 452. 
chrysophanic, 335. 
cinnamic, 334, 482. 
citric, 320, 638. 
colopholic, 478. 
colophonic, 478. 664 
INDEX 
Acid, copaivic, 480. 
cornic, 335. 
cresotic, 451. 
cresylic, 449, 451. 
cryptophanic, 504. 
cuminic, 472. 
cyanic, 335. 
dextroracemic, 317. 
dextrotartaric, 317. 
dithionic, 343. 
equisitic, 322. 
erucic, 467. 
ethyl-sulphuric, 433. 
eugenic, 472. 
ferulaic, 481. 
filicic, 467. 
fluoric, 339. 
formic, 335, 468 
gallic, 336, 356, 638. 
gambogic, 481. 
gaultheric, 446. 
gelseminic, 396. 
gentianic, 420. 
gentisic, 420. 
glacial acetic, 296, 526. 
guaiaconic, 421. 
guaiaretic, 421. 
guaiaretinic, 421. 
gummic, 407. 
hemidesmic, 336. 
liippuric, 336, 508, 511. 
hydriodic, 269. 
liydrobromie, 265, 565, 638. 
hydrochloric, 29, 262, 638. 
common, 262. 
dilute, 262. 
hydrocyanic, 275, 278, 638. 
dilute, 277. 
hydroferridcyanic, 338. 
hydroferrocyanic, 337. 
hydrofluoric, 339. 
hydrosulphuric, 298. 
hypochlorous, 289. 
hypophosphoric, 349. 
hypophosphorous, 340. 
hyposulphurous, 342. 
iodic, 293. 
jalapic, 422. 
lactic, 344, 565, 638. 
lsevoracemic, 317. 
lsevotartaric, 317. 
larixinic, 356. 
lauric, 468. 
litliic, 358. 
Acid, lupulinic, 481. 
malic, 345. 
rnastichic, 479. 
meconic, 346, 498. 
melissic, 468. 
metaboracic, 330. 
metagummic, 407. 
metantimonic, 178. 
metaphosphoric, 346. 
metastannic, 239. 
mimotannic, 355. 
mucic, 415. 
muriatic, 262. 
myristic, 468. 
myrrhic, 482, 
naphthalic, 333. 
nitric, 284, 286, 638. 
dilute, 284. 
nitrohydrochloric, 183, 285. 
dilute, 285. 
nitromuriatic, 285. 
nitrous, 347. 
cenanthylic, 468. 
oleic, 468, 638. 
ophelic, 348. 
opiaftic, 380. 
orthophosphoric, 348. 
oxalic, 313. 
chemically pure, 313. 
palmitic, 468. 
paratartaric, 317. 
parietinic, 335. 
pelargonic, 468. 
pentatli ionic, 343. 
perchloric, 291. 
phenic, 449. 
phosphomolybdic, 501. 
phosphoric, 25, 326, 348, 638. 
dilute, 326. 
glacial, 327. 
phosphorous, 348. 
phthalic, 333. 
picric, 450. 
pimaric, 478. 
pinic, 478. 
piperic, 398. 
propionic, 468. 
prussic, 275. 
pyrogallic, 357. 
pyroligneous, 294. 
pyrophosphoric, 349. 
racemic, 317. 
rheic, 335. 
rhubarbariy, 335. INDEX. 
665 
Acid, rutic, 468. 
saccharic, 415. 
salicylic, 446, 451, 639. 
salicylous, 446. 
santonic, 423. 
sarcolactic, 345. 
sclerotic, 478. 
sclerotinic, 478. 
silicic, 351. 
stannic, 239. 
stearic, 465, 468. 
succinic, 352. 
sulphethylic, 433. 
sulphindigotic, 287. 
sulphindylic, 287. 
sulphocarbolic, 450. 
sulphocyanie, 353. 
sulphophenic, 450. 
sulphosalicylic, 451. 
sulphovinic, 433. 
sulphuric, 304, 638. 
sulphuric, aromatic, 307. 
dilute, 307. 
sulphurous, 302, 638. 
sulphydric, 298. 
sylvie, 478. 
tanaeetic, 424. 
tannic, 354, 639. 
tartaric, 315, 316, 639. 
tetrathionic, 343. 
tiglic, 466. 
toxicodendric, 357. 
trinitrocarbolic, 450. 
trithionic, 343. 
tropic, 392. 
uric, 350. 
valerianic, 358, 468. 
Acid carbonate of potassium, 70, 
311. 
carbonate of sodium, 82. 
salts, 73, 299. 
solution of arsenic, 165. 
tartrate of potassium, 61, 79. 
tartrate of sodium, 79. 
Aeidimetry, 556. 
Acids, analytical detection of, 364. 
antidotes to, 265. 
definition of, 259. 
free, estimated, 600. 
of chlorine, 292. 
quantitative estimation of, 563. 
volumetric estimation of offi- 
cial, 563. 
Acidulous radicals, formulae and 
56 * 
quantivalence of, 66, 121, 
261. 
Acidulous radicals, qualitative de- 
tection of, 361. 
radicals, quantitative estima- 
tion of salts of, 600. 
radicals, tables to aid in the 
detection of, 363, 364. 
Acidum aceticum, 296. 
impurities in, 637. 
dilutum, 296. 
ylaciale, 296, 637. 
impurities in, 637. 
arseniosum, 164. 
benzoicum, 332, 637. 
bovicum, 330. 
impurities in, 637. 
carbolicum, 449, 637. 
crudum, 449. 
chromicum, 235, 637. 
citricum, 320. 
impurities in, 630. 
gallicurn, 356. 
impurities in, 638. 
hydrobromicum dilutum, 267. 
impurities in, 638. 
hydrochloricum, 29, 262. 
impurities in, 638. 
dilutum, 262. 
hydrocyanicurn dilutum, 277. 
impurities in, 638. 
lacticum, 344. 
impurities in, 638. 
nitricum, 284. 
impurities in, 638. 
dilutum, 284. 
nitro-liydrocliloricum dilutum, 
285. 
oleicum, 462. 
impurities in, 638. 
phosphoricum, 326. 
dilutum, 326. 
impurities in, 639. 
salicylieum, 451. 
impurities in, 639. 
mlphuric.um, 307. 
impurities in, 639. 
sulphuricnm aromaticum, 307. 
dilutum, 307. 
mlphurosum, 303. 
impurities in, 639. 
tannicum, 354. 
impurities in, 639. 
tartaricum, 316. 666 
INDEX. 
Acid am tartaricum, impurities in, 
639. 
Acipenser, 459. 
Aconiti ferocis radix, 392. 
folia, 391. 
heterophylli radix, 392. 
Aconitia, 391. 
Aconitic acid, 322. 
Aconitina, 391. 
Aconitine, 391. 
Aconitum, 392. 
ferox, 392. 
heterophylhan, 392. 
napellus, 391. 
Acorin, 474. 
Acorns calamus, 474. 
Acrinyl sulphocyanate, 453. 
Acrolein, 455. 
Acrylic acid (test for), 454. 
Actea racemosa, 400. 
Adeps, 464. 
impurities in, 639. 
benzoinatus, 464. 
Adhesion, 56. 
Adipocire, 459. 
yEyle marmelos, 355. 
Aerated bread, 412. 
water, 85. - 
Alsculin, 396. 
mixer, 432, 434. 
impurities in, 639. 
JE.her aceticus, 436. 
impurities in, 639. 
fortior, 434. 
impurities in, 639. 
purus, 434. 
Affinity, chemical, 38. 
African pepper, 394. 
Agate, 351. 
Air, composition, 26. 
influence of animals and plants 
on, 19. 
nitrogen in the, 26. 
oxygen in the, 16. 
relative weight of the, 26. 
weight of 1 cubic centimetre, 
548. 
weight of 100 cubic inches, 
548. 
Ajwain oil, 471. 
Alabaster, 103. 
Albumen, 455. 
detection of, in urine, 504. 
Albumen, vegetable, 459. 
Albumen ovi, 455. 
Albumenoid substances, 455. 
Alchemy, 13. 
Alcohol, 425. 
absolute, 428, 525. 
amylic, 445, 525. 
amylicum, 445. 
and allied bodies, 425 el seq. 
benzylic, 482. 
butylic, 360. 
cinnamic, 482. 
dilutum, 428. 
ethylic, 428. 
from sugar, 412. 
glyceric, 454. 
in 100 parts of spirits of dif- 
ferent densities, Table show- 
ing the proportion by weight 
of, 659. 
methylic, 439. 
phenic, 449. 
quantitative estimation of, 632. 
radicals, 437. 
real, 428. 
test for impurities in, 571, 639. 
test for purity of, 429, 571. 
Alcoholates of chloral, 445. 
Alcoholometer, 544. 
Alcohols, 437. 
Aldehyd, 430. 
benzoic, 333. 
euodic, 474. 
lauric, 474. 
rutic, 474. 
Aldehyds, 438. 
aromatic, 474. 
Ale, 406, 427. 
Alexandrian senna, 417. 
Algaroth’s powder, 178. 
Alizarin, 485. 
Alkalies, analytical separation of 
the, 99. 
antidotes to, 261. 
quantitative estimation of the, 
556. 
Alkalimetry, 562. 
Alkaline carbonates, volumetric es- 
timation of the, 556. 
earths, 124. 
solution of arsenic, 164. 
Alkaloids, 377. 
antidotes to the, 379. INDEX. 
667 
Alkaloids, distinguished, 378, 
391 
nomenclature of, 378. 
poisonous, examination for, 
493 et seq. 
Alkanet, 485. 
Al/canna tinctoria, 485. 
Allium, 453. 
Allotropes, 408. 
Allotropic bodies, 408. 
Allotropy, 408. 
Alloxan, 358. 
Alloy, 192. 
Alloys, analysis of, 372. 
Allspice, 472. 
Allyl, 453. 
cyanide, 453. 
sulphide of, 453. 
sulphocyanate of, 453. 
Almond-oil, 466. 
Almonds, oil of bitter, 416, 448. 
test for nitrobenzol in, 417. 
Aloe, 452. 
purificala, 452. 
socotrina, 452. 
Aloes, 452. 
Aloins, 452. 
Alstonia constricta, 395. 
sch olar in, 395. 
Alstonieine, 395. 
Alstonine, 395. 
Althea, 407. 
officinalis, 407. 
Alum, 135. 
cake, 136. 
chrome-, 136. 
dried, 137. 
flour, 135. 
iron, 136. 
potash-, 135. 
roche or rock, 137. 
root, 356. 
soda, 136. 
A lumen, 135. 
impurities in, 640. 
exsiccatum, 137. 
Alumina, 137. 
Aluminii hydras, 137. 
impurities in, 640. 
sulphas, 136. 
impurities in, 640. 
Aluminium, 135, 660. 
analytical reactions of, 137. 
and ammonium sulphate, 136. 
Aluminium and sodium, double 
chloride, 135. 
bronze, 135. 
derivation of word, 32. 
detection of, in presence of 
iron and zinc, 159. 
hydrate, 136. 
oxide, 137. 
quantitative estimation of, 591. 
separation of, from chromium 
and iron, 237. 
silicate, 136. 
sulphate, 136. 
Amalgam, 192. 
ammonium, 90. 
Amber, 352. 
oil, 352. 
American senna, 417. 
turpentine, 474. 
wormseed, 475. 
Amianth, 351. 
Amide, 202. 
Amido-chloride of mercury, 202. 
Amidogen, 202. 
Amines, 377. 
Ammonia, 90. 
detected by Nessler test, 558. 
fetid spirit, 92. 
gas, composition of, 90. 
in drinking waters, 558. 
preparation of, 90. 
solution of, 91. 
synthesis of, 90. 
type, 375. 
volcanic, 89. 
volumetric estimation of solu- 
tions of, 557. 
Ammoniaeal liquor, 89. 
salts, sources of, 89. 
Ammoniacum, 481. 
Ammoniac (vide Ammonii). 
Ammoniated glycyrrhizin, 421. 
mercury, 202. 
varieties of, 202. 
Ammonii acetatis liquor, 91. 
aqua, 91. 
fortior, 91. 
aromaticus, spirilus, 92. 
benzoas, 93, 333. 
impurities in, 640. 
bromidum, 93, 267, 569. 
impurities in, 640. 
volumetric estimation of, INDEX 
Ammonii carbonas, 91. 
impurities in, 92, 640. 
chloridum, 89. 
impurities in, 640. 
citratis, liquor, 93. 
fcetidus, spiritus, 92. 
fortior, liquor, 91. 
iodidum, 93. 
impurities in, 640. 
nitras, 92. 
impurities in, 641. 
phosphas, 93, 608. 
impurities in, 641. 
sulphas, 89. 
impurities in, 641. 
Valerianas, 360. 
impurities in, 641. 
Ammonio-chloride of mercury, 
202. 
-citi'ate of iron, 151. 
-ferric sulphate, 136. 
-ferric alum, 136. 
-magnesian phosphate, 119, 
328. 
-nitrate of silver, 174, 203. 
-sulphate of copper, 174, 203. 
-tartrate of iron, 152. 
Ammonium, 88. 
acetate, 91. 
amalgam, 90. 
analytical reaction, 96. 
and magnesium, arseniate of, 
119. 
and magnesium phosphate, 
119. 
and platinum, double chlo- 
ride, 97, 244. 
arseniate, 166. 
benzoate, 93, 333. 
bicarbonate, 91. 
bromide, 93, 267. 
carbamate, 91. 
carbonate, 93. 
solution of, 92. 
chloride, 89. 
citrate, 93. 
cyanate, 335. 
derivation of word, 32. 
derivatives, 203. 
glycyrrhizate, 421. 
hydrate, 90. 
iodide, 270. 
molybdate, 501. 
nitrate, 92. 
Ammonium, oxalate, 94. 
periodide, 270. 
phosphate, 93. 
potassium and sodium, sepa- 
ration of, 99. 
quantitative estimation of, 586. 
salts, source of, 89. 
volatility of, 97. 
sulphate, 89. 
sulphide, 94. 
sulphydrate, 94. 
tartrate, 97. 
valerianate, 360. 
volumetric estimation of car- 
bonate of, 558. 
Amorphous, meaning of, 181. 
phosphorus, 327. 
Amygdala am am, 416. 
dulcis, 416. 
Amygdalin, 416. 
Amyl, 445. 
acetate, 446. 
nitrite, 446. 
impurities in, 641. 
valerianate, 446. 
Amylaceous substances, 401. 
Amvlamine, 378. 
Amvlic alcohol, 445. 
Amylum, 401. 
iodatum, 405. 
Amyric acid, 480. 
Amyrin, 480. 
Anacyclus pyrethrum, 479. 
Analogies between chlorine, bro- 
mine, and iodine, 275. 
of sodium and potassium salts, 
87. 
Analogy of carbon, boron, and sil- 
icon, 330, 352. 
of oxygen, sulphur, selenium, 
and tellurium, 299. 
of salts, 87. 
Analysis, 98. 
aided by sifting, 368. 
blowpipe, 369. 
gas, 357, 491. 
gravimetric, 520. 
meaning of word, 60. 
organic, 611. 
practical, 98. 
proximate, 611. 
qualitative, 99. 
quantitative, 519. 
spectral, 491. INDEX. 
Analysis, systematic, for the detec- 
tion and separation of the 
metals, 99, 122, 161, 183, 
186, 219, 370. 
ultimate, 611. 
volumetric, 521, 554. 
Analysis and synthesis, 60. 
of gases and vapors, 491. 
insoluble salts, 370 et seq. 
medicines, 377. 
salts, 367. 
substances having unknown 
properties, 370. 
Analytical chemists, 14, note. 
detection of the acidulous 
radicals of salts soluble in 
water, 361. 
memoranda, 256, 261. 
Analytical reactions of ace- 
tates, 297. 
albumen, 455. 
alcohol, 429. 
aldehyd, 430. 
aluminium, 137. 
ammonium, 96. 
amygdalin, 416. 
antimony, 180, 494. 
arsenicum, 167, 494. 
atropine, 392. 
barium, 102. 
beberine, 393. 
benzoates, 334. 
berberine, 394. 
bile, 464. 
bismuth, 250. 
borates, 331. 
bromides, 268. 
brucine, 390. 
cadmium, 246. 
caffeine, 398. 
calcium, 113. 
carbonates, 311. 
chloral hydrate, 445. 
chlorates, 292. 
chlorides, 264, 495. 
chromates, 235. 
chromium, 236. 
citrates, 323. 
cobalt, 230. 
coniine, 395. 
copper, 189. 
cyanides, 279. 
ferric salts, 158. 
ferridcyanides, 339. 
Analytical reactions of fer- 
roevan ides, 337. 
ferrous salts, 157. 
fluorides, 339. 
formates, 336. 
gallic acid, 356. 
glucosides, 416. 
glycerin, 454. 
gold, 242. 
guaiacin, 421. 
hippurates, 337. 
hydrocyanic acid, 279, 496. 
hypochlorites, 289. 
hypophosphites, 342. 
hyposulphites, 344. 
iodides, 271. 
iron, 157. 
lactates, 345. 
lead, 210, 494. 
lithates, 358. 
lithium, 224. 
magnesium, 119. 
malates, 345. 
manganese, 228. 
meconates, 346, 498. 
mercuric salts, 201, 204. 
mercurous salts, 203, 204. 
metaphosphates, 347. 
morphine, 381, 498. 
nickel, 232. 
nicotine, 397. 
nitrates, 285. 
nitrites, 347. 
nitrous ether, 435. 
oxalates, 313, 496. 
phosphates, 328. 
phosphites, 348. 
platinum, 244. 
potassium, 77. 
pyrogallic acid, 357. 
pyrophosphates, 350. 
quinine, 385. 
salicin, 423. 
silicates, 351. 
silver, 215. 
sodium, 87. 
starch, 404. 
strontium, 225. 
strychnine, 389, 497. 
succinates, 352. 
sugar, 411. 
sulphates, 307. 
sulphides, 301. 
sulphites, 303. 670 
INDEX 
Analytical reactions of sul- 
phocyanates, 353. 
sulphuric acid, 307. 
, tannic acid, 354. 
tartrates, 319. 
theine, 399. 
tin, 239. 
urates, 357. 
veratrine, 399. 
zinc, 133. 
Anumirta cocculus, 422. 
paniculata, 422. 
Anamirtin, 422. 
Anchusa tinctoria, 485. 
Ancliusin, 485. 
Andria araroba, 335. 
Andrographis paniculata, 400. 
Andropogon citratus, 475. 
nardus, 472. 
sdicenanthus, 473. 
Anemone pratensis, 332. 
patens, 332. 
pulsatilla, 332. 
Anemonic acid, 332. 
Anemonin, 332. 
Aneroid barometer, 522. 
Anethene, 471. 
Anethol, 471. 
Angelic acid, 471. 
powder, 177. 
Angelica, 471. 
Angustura bark, 400. 
Anhydride, acetic, 296. 
antimonic, 177. 
antimonious, 177. 
boracic, 330. 
carbonic, 311. 
chlorochromic, 236. 
chromic, 235. 
nitric, 281, 286. 
nitrous, 286. 
phosphoric, 25, 348. 
silicic, 351. 
sulphuric, 307. 
sulphurous, 302. 
Anhydrides, 84. 
Anhydrous bodies, 84. 
nitric acid, 285. 
perchloride of iron, 144. 
sulphate of copper, 188. 
Aniline, 451, 487. 
colors, 487. 
Animal charcoal, 110. 
decolorizing power of, 110. 
Animal rouge, 486. 
Animals and plants, complement- 
ary, action of air, 19. 
Anise, 471. 
Aniseed oil, 471. 
Anise-fruit, 471. 
Anisum, 471. 
Annatto, 485. 
Anthemis, 471. 
nobilis, 471. 
Anthemidis fiores, 400, 471. 
Anthracene, 452. 
Anthracite, 237. 
Antichlor, 303. 
Antidotes to acids, 261. 
alkalies, 261. 
alkaloids, 379. 
antimony, 182. 
arsenic, 148, 174. 
barium, 102. 
carbolic acid, 450. 
copper, 190. 
cyanides, 280. 
hydrochloric acid, 265. 
hydrocyanic acid, 280. 
lead, 211. 
mercury, 205. 
nitric acid, 288. 
oxalic acid, 314. 
silver, 216. 
sulphuric acid, 308. 
tin, 241. 
zinc, 134. 
Antimonial wine, 179. 
Antimoniate of potassium, 87. 
sodium, 87. 
Antimonic anhydride, 178. 
chloride, 177. 
oxide, 178. 
Antimonii. chloridii, liquor, 177, 
594. 
et potassii tartras, 178. 
impurities in, 641. 
quantitative estimation of 
antimony in, 594. 
oxidum, 177. 
impurities in, 641. 
sulphidum, 176. 
purification, 176. 
impurities in, 641. 
sulphur at urn, 179. 
impurities in, 641. 
Antimonious anhydride, 178. 
chloride, 177. INDEX. 
Antimonious oxide, 177. 
oxychloride, 177. 
Antimoniurn sulphuratum, 179. 
estimation of, 594. 
Antimoniuretted hydrogen, 181. 
Antimony, 163, 176, 316, 527. 
analytical reactions of, 180. 
and arsenic, analytical sepa- 
ration of, 183. 
and potassium tartrate, 178, 
316. 
antidote to, 182. 
black, 176. 
butter, 177. 
chloride, 177. 
crude, 176. 
derivation of word, 32. 
from arsenic, to distinguish, 
171. 
hydride, 181. 
in organic mixtures, detection 
of, 494. 
oxide, 177. 
oxychloride, 177. 
oxvsulphide, 179. 
pentaehloride, 177. 
potassio-tartrate, 178. 
quantitative estimation of, 
594. 
solution of chloride of, 177. 
sulphide, 176, 180. 
sulphur, salts of, 179. 
sulphurated, 179. 
tartrated, 178. 
Antiseptic, 450. 
Antozone, 235, 272, 512. 
Apocynum, 400. 
Apomorphince hydrochloras, 382. 
Apomorphine, 382. 
Aporetine, 335. 
Apothecaries, 14. 
Apparatus, xi. 
for experiments, xi. 
for gravimetric analvsis, 582, 
591, 596, 597, 602, 606, 612, 
613, 615. 
for volumetric analysis, 554. 
list of, xi. 
Apple, acid in, 345. 
essence, 446. 
oil, 446. 
wine, 427. 
Aqua, 126. 
ammonice, 91. 
Aqua ammonia?, impurities in, 
641. 
volumetric estimation of, 
557. 
ammonice fortior, 91. 
impurities in, 641. 
amygdalcB amarce, 416. 
anisi, 470. 
auruntii florum, 470. 
impurities in, 641. 
camphorce, 476. 
chlori, 28, 264. 
chloroformi, 443. 
cinnamomi, 470. 
fceniculi, 470. 
creasoti, 449. 
destillata, 126. 
impurities in, 642. 
fortis, 285. 
laurocerasi, 416. 
menlhce piper itte, 47 0. 
viridis, 470. 
regia, 183, 285. 
rorce, 470, 473. 
Arabin, 112. 
Arachidic acid, 468. 
Arachis hypogsea, 467. 
Arachis oil, 467. 
Araroba powder, 335. 
Arbor Dianas, 216. 
Arbor vitce, 474. 
Arbutin, 356, 417. 
Archil, 486. 
Arctium lappa, 400. 
Arctostaphylos uva-ursi, 417. 
Are, 532. 
Areca catechu, 356. 
Areea-nuts, 356. 
Argal, 315. 
Argent-ammon-ammonium, nitrate 
of, 203. 
Argenti cyanidum, 215. 
iodidvm, 215. 
impurities in, 642. 
nitras, 213, 599. 
gravimetric estimation of, 
598. 
impurities in, 617. 
d Hut us, 214, 599. 
fusrn, 214, 599. 
oxidum, 214, 599. 
impurities in, 642. 
Argentic chloride, sulphide, etc. 
(vide Salts of Silver). INDEX. 
Argentiferous galena, 212. 
Argentum, 33. 
Argentum purificatum, 214. 
Argol, 315. 
Armenian bole, 485. 
Armoracice radix, 471. 
Arnatto, 485. 
Arnica, 478. 
Arnicce radix, 478. 
flores, 478. 
Arnicin, 478. 
Arnotto, 485. 
Aromatic aldehyds, 473. 
Arrowroot-starch (fig ), 403. 
Arseniate of ammonium, 166. 
barium, 103, 174. 
calcium, 174. 
copjjer, 173. 
iron, 167, 576. 
magnesium and ammonium, 
119. 
silver, 174. 
sodium, 166. 
zinc, 174. 
Arseniates, 166. 
Arsenic acid, 166. 
and arsenical solutions, volu- 
metric estimation of official, 
573. 
anhydride, 166. 
in carbonate of potassium, so- 
lution of, 164. 
in hydrochloric acid, solution 
of, 165. 
odor of, 165. 
white, 164. 
antidote to, 148, 174. 
Arsenical ores, 163. 
sulphur, 172. 
Arsenii iodidum, 163. 
Arsenicum, 163. 
analytical reactions of, 167. 
antidotes to, 148, 174. 
and antimony, analytical sep- 
aration of, 183. 
bromide, 163. 
chloride, 163. 
derivation of word, 32. 
detection of, in metallic cop- 
per, 169. 
detection of, in ores, 174. 
detection of. in organic mix- 
tures, 494. 
Fleitmann’s test for, 171. 
Arsenicum from antimony, to 
distinguish, 171. 
hydride, 170. 
iodide, 163. 
Marsh’s test for, 169. 
quantitative estimation of, 573, 
593. 
red native sulphide, 164. 
reduction of arseniates to ar- 
senites, 166. 
Reinsch’s test for, 169. 
sources of, 163. 
sulphide, 164, 172. 
yellow native sulphide, 164. 
Arsenide of cobalt, 230. 
Arsenio-sulphide of iron, 163. 
of nickel, 232. 
Arsenious acid, 164. 
anhydride, 164. 
oxide, 164. 
Arsenites, 164. 
Arsenite of copper, 173. 
potassium, 164. 
silver, 173. 
sodium, 166. 
Arseniuretted hydrogen, 170. 
Art of Chemistry, 13. 
Artemisia absinthium, 472. 
maritima, 423. 
Artificial alkaloids, 377. 
gastric juice, 460. 
Asafcetida, 481. 
Asbestos, 351. 
Asclepedin, 400. 
Asdepias tuberosa, 400. 
Ash, 100. 
black-, 86. 
bone-, 109. 
soda-, 86. 
Ashes, analysis of (mixed solids), 
370. 
Asparagin, 346. 
Aspartate of ammonium, 316. 
A spit Hum, 467. 
Aspidospermine, 392. 
Aspirator, water, 303. 
-ate, meaning of, 72. 
Atees, 392. 
Atis, 392. 
Atmosphere, carbonic acid in, 
310. 
composition of, 26. 
nitrogen in, 26. 
oxygen in, 15, 26. INDEX. 
673 
Atmospheric pressure, measure- 
ment of, 511. 
Atom, definition of, 56. 
weights, definition of, 51. 
Atomic proportions, 194, 197. 
theory, 50. 
weights, 51. 
relation of specific heat 
to, 550. 
Atomicity, 53. 
Atoms, 50, 51. 
quanti valence of, 55. 
definition of, 56. 
Atropa belladonna, 392. 
Atropia, tropate of, 392. 
Atropina, 392. 
impurities in, 642. 
Atropines sulphas, 392. 
impurities in, 642. 
Atropine, 392. 
Attar of rose, 473. 
Aurantii amari cortex, 471. 
dulcis cortex, 400, 471. 
fiores, 471. 
Auric chloride, 242. 
sulphide, 242. 
Auri et sodii chloridum, 242. 
impurities in, 642. 
Aurum, 34. 
impurities in, 642. 
Avignon grains, 484. 
Avogadro’s and Ampere’s law, 52, 
53. 
Azadiracta. indica, 400. 
Azedarach, 400. 
Bacterium mycodermi, 294. 
Bael fruit, 355. 
Bahia powder, 335. 
Baking-powder, 412. 
Balance, 528. 
Balloons, coal-gas for, 24. 
hydrogen for, 24. 
Balm, 473. 
Balm-of-Gilead fir, 481. 
Balsam, Canada, 481. 
copaiva, 480. 
fir, 474. 
Gurjun, 480. 
Peru, 482. 
Storax, 482. 
Tolu, 483. 
Balsamodendron myrrha, 482. 
Balsams, 482. 
Balsam am Peruvianum, 482. 
impurities in, 642. 
Tolutanum, 334, 483. 
Baptism tinctoria, 400. 
Barbadoes aloes, 452. 
Barbaloin, 452. 
Barberry, 393. 
Barff’s protected iron, 139. 
Baric chloride, nitrate, etc. (vide 
Salts of Barium). 
Barium, 101. 
aeetonitrate, 124. 
analytical reactions of, 102. 
and calcium, separation of, 
from magnesium, 122. 
antidotes to, 102. 
arseniate, 103. 
carbonate, 103. 
native, 101. 
chloride, 101. 
chromate, 102. 
derivation of word, 32. 
detection of, in presence of 
calcium and magnesium, 
122. 
hydrate, 101. 
nitrate, 101. 
peroxide, 102. 
phosphate, 103, 329. 
oxalate, 103, 314. 
quantitative estimation of, 
587. 
salts, antidote to, 102. 
silico-fluoride, 103. 
sulphate, 102. 
sulphide, 101. 
sulphite, 304. 
Barley-starch (fig.), 403. 
Barley-sugar, 414. 
Barometer, 521. 
Baryta, 101. 
-water, 101. 
Basalt, 135. 
Base, meaning of, 259. 
organic, 376. 
Bassorin, 113, 407. 
Bastard saffron, 485. 
Basylous radicals, 121. 
Bath brick, 351. 
Bauxite, 135. 
Bay, 473. 
Bay rum, 427. 
salt, 80. 
Bearberry, 356. INDEX. 
Beaver, 478. 
Beaver tree, 401. 
Beberia or beberine, 393. 
Beberice sulphas, 393. 
Beberine, 393. 
Beer, 406. 
Beeswax, 465. 
Beetroot, 411. 
Bela fructus, 355. 
Belladonna? folia, 392. 
radix, 392. 
Bell-metal, 238. 
Bend glass tubes, to, 17. 
Benne oil, 467. 
Benzaldehyd, 416. 
Benzene, 448. 
Benzin, 448. 
Benzine, 448. 
Benzinum, 448. 
impurities in, 642. 
Benzol-disulphonic acid, 450. 
Benzoline, 448. 
Benzin-Collas, 448. 
Benzoate of ammonium, 93, 333. 
Benzoated lard, 464. 
Benzoates, 332. 
Benzoic acid, 332, 524, 526. 
aldehyd, 333. 
glycocine, 334. 
Benzoin, 332, 482. 
Benzoinum, 332, 482. 
Benzol, 448. 
Benzyl benzoate, 4S2. 
cinnamate, 482. 
hydrate, 334. 
hydride, 416, 482. 
Benzylic alcohol, 482. 
Berberia or berberine, 393. 
Berberis cortex, 393. 
Bergamot oil, 471. 
Berlin blue, 486. 
red, 485. 
Berthollet’s laws, 376. 
Beryllium, 660. 
Betel nuts, 356. 
Bi-, the prefix, 71. 
Bibasic (vide Dibasic). 
Bibirine, 393. 
Bibulous paper, 106. 
Bicarbonate of ammonium, 91. 
of potassium, 70, 318, 322, 
560. 
chemically pure, 561. 
Bicarbonate of sodium, 82, 318, 
322, 560. 
chemically pure, 561. 
Bichromate of potassium, 234. 
Bikh, 392. 
Bile, 464. 
detection of, in urine, 505. 
tests for presence of, 464. 
Biliary calculi, 516. 
Bish, 392. 
Bismuth, 246, 527, 515, 595. 
and ammonium citrate, 249. 
analytical reactions of, 250. 
carbonate, 249. 
citrate, 249. 
derivation of word, 34. 
hydrate, 250. 
lozenge, 248. 
nitrate, 247. 
oxide, 249. 
oxy-salts, 248. 
quantitative estimation of, 595. 
salts, composition of, 249. 
subcarbonate or oxy carbon ate, 
249. 
subnitrate or oxynitrate, 247. 
sulphate, 249. 
sulphide, 250. 
Bismuthi ccnbonas, 249. 
estimation of bismuth in, 
595. 
impurities in, 642. 
citras, 249. 
impurities in, 617. 
et ammonii citras, 249. 
impurities in, 617. 
oxidum, 249. 
subcarbonas, 249. 
subnitras, 247. 
impurities in, 642. 
Bisulphide of carbon, 438. 
Bisulphite of lime, 303. 
sodium, 303, 574. 
Bitter almonds, oil of, 416, 471. 
cassava, 402. 
principles, 400. 
-sweet, 398. 
Bittern, 266. 
Bituminous coal, 237. 
Bivalence, 55. 
Bivalent radicals, 55, 121. 
Bixa orellana, 485. 
Bixin, 485. INDEX. 
675 
Black antimony, 176. 
alder, 356. 
alder, buckthorn, 418. 
ash, 86. 
-band, 139. 
bone-, 110. 
cherry bark, 417. 
coloring-matters, 487. 
dyes, 487. 
flux, 165. 
haw, 401. 
hydrate of iron, 153. 
ink, 355.' 
-lead, 30- 
oak, 484. 
oxide of copper, 188. 
of iron, 153. 
of manganese, 226. 
of mercury, 200, 
pepper, 397. 
snakeroot, 400. 
Blackberry, 356. 
Bladder-green, 487. 
Blanc de perle, 248. 
Bleaching by chlorine, 29, 
-liquor, 112. 
-powder, 111. 
Blende, 128. 
Block tin, 237. 
Blood, 456, 511. 
detection of, in organic mat- 
ter, 512. 
hydrocyanic acid in the, 280. 
Blood-root, 398. 
vinegar, 295. 
Blood-stains, 512. 
Blowpipe analysis, 369. 
Blue cohosh, 400. 
coloring-matters, 487. 
copperas, 141. 
flag, 400. 
indigo, 291. 
mass, 191. 
ointment, 191. 
pill, 191. 
Prussian, 158, 338. 
stone, 188. 
Turnbull’s, 339. 
vitriol, 141, 188. 
Boiled oil, 466. 
Boiling-points of various sub- 
stances, 525. 
-point, definition of, 525. 
Boldo, 472. 
“Bonds” (Frankland), 135. 
Bondue seeds, 400. 
Bone-ash, 109. 
-black, 110. 
-earth, 324. 
Bones, composition of, 324. 
Boneset, 400. 
Boracic acid, 330. 
anhydride, 330. 
as an antiseptic, 331. 
Borates, 330. 
analytical reactions of, 331. 
Borax, 330. 
volumetric estimation of, 559. 
■ bead, 231. 
Bordeaux turpentine, 475. 
Boric acid (see Boracic acid), 330. 
Borneene, 470. 
Borneo camphor, 476. 
Boron, 330. 
chloride, 330. 
derivation of word, 330. 
flame, 331. 
fluoride, 330. 
Borotartrate of potassium, 331. 
Bos taurus, 404. 
Boswellia, 482. 
Bourdon barometer, 522. 
Boyle’s law, 52. 
Brandv, 427, 431. 
Brass, 128. 
Bray era, 479. 
Brazil-powder, 335. 
-wood, 485. 
Bread, 401, 412. 
aerated, 412. 
-making, 412. 
Breidin, 480. 
Brezilin, 485. 
Bright’s disease, 504. 
Britannia metal, 170, 200. 
British gum, 405. 
Bromal, 445. 
alcoholates of, 445. 
hydrate of, 445. 
Bromate of potassium, 76. 
Bromates, 208, 293. 
detection of, in bromides, 268. 
Bromic acid, 76, 293. 
Bromide of ammonium, 267, 569. 
arsenicum, 163. 
calcium, 267. 
ethyl, 436. 
iron, 144. INDEX 
Bromide of lithium, 223. 
potassium, 75, 267, 569. 
volumetrical estimation 
of, 569. 
silver, 215. 
sodium, 267, 570. 
sulphur, 301. 
Bromides, 267. 
analytical reactions of, 268. 
quantitative analysis of, 569, 
601. 
separation of, from chlorides 
and iodides, 273. 
Bromine, 265. 
analytical separation of, 268. 
derivation of word, 33. 
its analogy to chlorine and 
iodine, 269. 
solution of, 268. 
test of purity, 266. 
volumetric estimation of free, 
601. 
Bromum, 273. 
impurities in, 642. 
Bronze, 240. 
aluminium, 135. 
coinage, 187. 
Bronzing-powder, 240. 
Broom-tops, 398. 
Brown coloring-matters, 487. 
haematite, 138. 
rosin, 478. 
sugar, 411. 
Brupia, 390. 
Brucine, 390. 
Brunswick green, 173. 
Brvoidin, 480. 
Bryonia, 417. 
Bryonin, 417. 
Bryony, 417. 
Buchu, 472. 
oil of, 472. 
Buckthorn green, 486. 
-juice, 418. 
“Bumping,” 277. 
Bunsen gas-burners, 23. 
valve, 583. 
Burdock, 400. 
Burette, Mohr’s, 555. 
Burgundy pitch, 479. 
Burners, gas, 17, 23. 
Burnett’s disinfecting fluid, 130. 
Burnt ochre, 485. 
sugar, 415. 
Burnt umber, 487. 
Bntea frondosa, 355. 
Butter, 457. 
of antimony, 177. 
cacao, 405. 
cocoa, 405. 
kokum, 405. 
orris, 473. 
Butternut, 396. 
Butyl, 300. 
chloral, 415. 
sulphocyanate, 438. 
Butyl ic alcohol, 360. 
Butyrates, 360. 
Butyric acid, 360, 438, 468. 
Buxine, 393. 
Burns sempervirens, 393. 
By-products, 196. 
Cacao butter, 465. 
Cacaotine, 465. 
Cadmii iodidum, 246. 
Cadmium, 246. 
analytical reactions of, 246. 
carbonate, 246. 
derivation of word, 34. 
hydrate, 245. 
iodide, 246. 
nitrate, 246. 
sulphate, 246. 
sulphide, 246. 
Ccesalpina braziliensis, 485. 
bonducella, 400. 
Caesium, 660. 
Caffeina, 398. 
impurities in, 643. 
Cajuput oil, 472. 
Cajuputene, 472. 
Cajuputol, 472. 
Caking coal, 237. 
Calabar bean, 397. 
Calamine, 128. 
Calamus, 474. 
draco, 478. 
Calcic sulphate, phosphate, etc 
(vide Salts of Calcium). 
Calcii bromidum, 267. 
impurities in, 643, 
carbonas prcecipitalus, 106. 
impurities in, 643. 
chloratce, liquor, 112. 
chloridum, 104. 
impurities in, 643. 
hypophosphis, 341. INDEX. 
677 
Calcii hypophosphis, impurities in, 
643. 
phosphas prcecipilatus, 110. 
impurities in, 643. 
saccharatus, liquor, 106. 
Calcined magnesia, 118. 
Calcium, 103. 
analytical reactions of, 113. 
and barium, separation from 
magnesium, 122. 
bisulphite, 303. 
bromide, 267. 
carbonate, 106. 
prepared, 108. 
chloride, 103. 
chromate, 113. 
citrate, 321. 
derivation of word, 32. 
-flame, 114. 
fluoride, 103. 
in bones, 109. 
glyeyrrhizate, 418. 
gunnnate, 112. 
hydrate, 106. 
hypochlorite, 111. 
hypophosphite, 341. 
hyposulphite, 300. 
in presence of barium and 
magnesium, detection of, 
122. 
oxalate, 113, 314. 
oxide, 105. 
phosphate, 103, 109. 
polysulphide, 300. 
quantitative estimation of, 588. 
silicate, 103, 351. 
sulphate, 103, 113, 300. 
sulphide, 112. 
sulphite, 303. 
superphosphate, 324. 
tartrate, 319. 
Calc-spar, 103. 
Calculi, urinary, 514. 
examination of, 514. 
Calendula, 400. 
Calendulin, 400. 
Calomel, 192, 199. 
test for corrosive sublimate in, 
199. 
tests for constituents of, 199. 
Calotropis, 400. 
Calurnba, 393. 
Calx, 105. 
impurities in, 643. 
Calx chlorata, 111. 
sulphurala, 114. 
Oambogia, 480. 
impurities in, 643. 
'Camphor laurel, 476. 
oil, 476. 
-water, 476. 
Camphora, 476. 
cinnamomum, 476. 
monobromata, 476. 
j Camphoretic acid, 476. 
| Camphoric acid, 476. 
peroxide, 469. 
! Camphors, 476. 
Camwood, 485. 
Canada balsam, 481. 
pitch, 481. 
Canadian hemp, 400. 
moonseed, 393. 
turpentine, 474. 
Candle-dame, composition of, 23. 
Candice albce cortex, 400. 
Cane-sugar, 411. 
Cannabene, 478. 
hydride of, 478. 
Cannabin, 478. 
Cannabis americana, 478. 
indica, 478. 
Cantharides, 477. 
Cantharidie acid, 477. 
Cantharidin, 477. 
Cant liar is, 477. 
Caoutchouc, 483. 
Capacity unit, 531. 
Capillary, 523. 
Caproate of glyceryl, 465. 
Caproic acid, 465, 468. 
Caproyl, 438. 
Caprylate of glyceryl, 465. 
Caprylic acid, 465, 468. 
Capsaicin, 394. 
Capsicum, 394, 479. 
Capsieia, 394. 
Capsicin, 479. 
Capsicine, 394. 
Capsicum, 394, 479. 
fruit, resin of, 394. 
oil, 479. 
Caramel, 415. 
Caraway oil, 472. 
Carbamate of ammonium, 91. 
Carbazotic acid, 450. 
Carbolic acid, 449, 525, 526. 
antidote to, 450. INDEX 
Carbo animalis, 110. 
purificalus, 110. 
impurities in, 643. 
ligni, 110. 
Carbon, 30. 
bisulphide, 310. 
combustion of, 30. 
derivation of word, 31. 
disulphide, 310. 
quantitative estimation of, in 
organic compounds, 611 et 
seq. 
Carbonate of ammonium, 91. 
solution of, 92. 
barium, 103. 
bismuth, 249. 
cadmium, 246. 
calcium, 103, 106. 
prepared, 108. 
iron, 141, 577. 
saccharated, 142, 577. 
lead, 211. 
lithium, 223. 
magnesium, 116. 
potassium, 61. 
acid, 70, 560. 
chemically pure, 561. 
sodium, 80, 86, 313, 560. 
acid, 82, 560. 
chemically pure, 561. 
manufacture of, 86, 311. 
strontium, 224. 
zinc, 131, 134. 
Carbonates, 309. 
acidulous radical in, 309. 
analytical reactions of, 311. 
gravimetric estimation of, 606. 
volumetric estimation of al- 
kaline, 560. 
Carbonei bisiilphidurn, 310. 
impurities in, 643. 
Carbonic acid, 30, 309. 
acid gas, generation of, 71. 
solubility of, in water, 85. 
anhydride, 309. 
oxide, 309, 336. 
Carbonization, 100. 
Cardamom oil, 472. 
Cardamomum, 472. 
greater, 472. 
lesser, 472. 
Carica papaya, 461. 
Carles’s process for valuation of 
cinch on a-bark, 623. 
Carmine, 334. 
Carminic acid, 334. 
Carnal life, 60. 
Carolina jasmine, 396. 
Carrageen moss, 407. 
Carrotin, 485. 
Carthamin, 485. 
Carthamiis tinctorius, 485. 
Carum, 472. 
ajowan, 471. 
Carvene, 472. 
Carvol, 472. 
Caryophvllin, 472. 
Caryophylltis, 472. 
Casein ilia, 472. 
oil, 472. 
Casein, 457. 
vegetable, 459. 
Cassia acutifolia, 417. 
elongata, 417. 
fistula, 411. 
oil, 472. 
Castanea, 355. 
Castile soap, 464. 
Custillou elustica, 483. 
Cast iron, 139, 527. 
Castor, 478. 
fiber, 478. 
oil, 467. 
Castoreum, 478. 
Castorin, 478. 
Cateehin, 355. 
Catechu, 355. 
pallidum, 355. 
Catechuic acid, 355. 
Cathartic acid, 417. 
Cathartogenic acid, 417. 
Caulophyllum thalictroides, 400. 
Caustic, 214. 
alcohol, 428. 
lime, 105. 
lunar, 214. 
potash, 61. 
soda, 81. 
Cayenne pepper, 394. 
Cedra oil, 471. 
Cedrene, 474. 
Celandine, 395. 
Celestine, 224. 
Cellulin, 409. 
Cellulose, 409. 
Celsius’s thermometer, 523. 
Cements, 351. 
Centiare, 531. INDEX. 
679 
Centigrade thermometer, 523. 
Cephidis ipecacuanha, 395. 
Cera alba, 465. 
impurities in, 643. 
Jlava, 465. 
impurities in, 643. 
Cerasin, 467. 
('erasus serotiva, 417. 
Cerates, 517. 
Ceratum pluvibi acetatis, 208, 
Cerebrin, 457. 
Ceresine, 465. 
Cerii oxalis, 226. 
impurities in, 643. 
Cerite, 226. 
Cerium, 226. 
derivation of word, 33. 
oxalate, 226. 
Ceroleine, 465. 
( 'erotic acid, 468. 
Cerevisice fermenlum, 425. 
Cetaceum, 465. 
impurities in, 644. 
Cetene, 465. 
Cetraria, 334. 
Cetraric acid, 334. 
Cetyl hydrate, 465. 
palmitate, 465. 
Cevadilla, 399. 
Cevadilline, 399. 
Cevadine, 396, 399. 
Ceylon moss, 407. 
Chalcedony, 351. 
Chalk, 108. 
precipitated, 106. 
prepared, 108. 
-stones, 514. 
Chalybeate water, 139. 
Chameleon mineral, 228. 
Chamomile oil, 471. 
Char, 100. 
Charcoal, 30. 
animal, 110. 
decolorizing power of, 
110. 
wood, 110. 
Charles’s law, 52. 
C'harta sinapis, 453. 
polassii nitratis, 282. 
Chartreuse, 427. 
Chavicce nffirinaritm, 397. 
Chavicic acid, 398. 
Cheese, 457. 
Chelerythrin, 394, 393. 
Chelidonic acid, 394. 
Chelidonine, 394. 
Cheiidonium, 394. 
Chemical action, definition of, 36, 
40. 
by symbols, illustration 
of, 41, 46. 
affinity, 38. 
combination, 38. 
by weight, laws of, 47, 58 
et seq. 
by volume, laws of, 52 
et seq. 
different from mechan- 
ical, 36, 38. 
laws of, 47, 191, 283, 520. 
compound, 30. 
definition of, 57. 
diagram, 57, 62. 
equation, 57, 62. 
force, 37, 56. 
conditions for the mani- 
festations of, 40. 
its relations to heat and 
electricity, 550. 
formula, definition of, 57. 
formulae, 41, 42. 
notation, 40, 41, 42. 
philosophy, principles of, 36 
et seq. 
preparations of the Pharma- 
copoeias, 517. 
symbol, definition of, 57. 
symbols, 31, 40, 41, 42. 
toxicology, 492. 
Chemicals, 14. 
list of, xiii. 
Chemism, 38. 
Chemist and Druggist, 14. 
Chemistry, art of, 13. 
and physics, differences be- 
tween, 46. 
definition of, 56. 
derivation of the word, 13. 
inorganic, 376. 
object of, 14, 48. 
organic, 376. 
science of, 13. 
Chemists, analytical, 14. 
manufacturing, 14. 
pharmaceutical, 14. 
Chenopodinm, 475. 
oil, 485. 
Cherry-laurel water, 417. 680 
INDEX 
Cherry, 320, 411. 
-tree gum, 407. 
wild black, 417. 
Chestnut, 355. 
-brown, 487. 
Chian turpentine, 474. 
Chili saltpetre, 282. 
Chimaphila, 417. 
umbellata, 417. 
China clay, 351. 
Chinese red, 485. 
yellow, 484. 
Cliinoidin, 387, 619. 
Chinoidinum, 388, 603. 
impurities in, 644. 
iodosulphate, 619. 
Chinoline, 387. 
Chirata, 348. 
Chiratin. 348. 
Chiratogenin, 348. 
Chloral, 443. 
alcoholates of, 445. 
butyl, 445. 
croton, 445. 
hydras, 443. 
impurities in, 644. 
hydrate, 443. 
Chlorate of potassium, 290. 
preparation of oxygen 
from, 16. 
Chlorates, 290. 
analytical reactions of, 292. 
Chloric acid, 289. 
Chloride of ammonium, 89. 
antimony, 177. 
arsenicum, 163. 
barium, 102. 
boron, 330. 
calcium, 103. 
removal of iron from, 
104. 
chromium, 234. 
gold, 242. 
iron, 144. 
lead, 210. 
lime, 111. 
magnesium, 115. 
manganese, 227. 
mercuric ammonium, 203. 
mercurous ammonium, 203. 
mercury, 197. 
platinum, 243. 
and ammonium, 97, 244, 
Chloride of platinum and lithium, 
224. 
and potassium, 79, 245. 
silicon, 352. 
silver, 213. 
sulphur, 301. 
tin, 238. 
solution of, 238. 
zinc, 130. 
Chlorides, 261. 
estimation of, 600. 
separation of, from bromides 
and iodides, 273. 
tests for, 264. 
Chlorinated lime, 111. 
volumetric estimation of, 580. 
soda, solution of, 86. 
volumetric estimation of, 
580. 
Chlorine, 27, 264, 600. 
acids, 292. 
as a disinfectant, 29. 
bleaching by, 28. 
collection of, 27. 
derivation of word, 31. 
its analogy to bromine and 
iodine, 269, 273. 
liquid, 264. 
percentage in hydrochloric 
acid, 628. 
preparation of, 28. 
properties of, 27. 
relative weight of, 28. 
solubility in water, 28. 
the active agent in bleaching- 
powder, 111. 
volumetric estimation of, 580. 
-water, 28, 264. 
Chlorochromic anhydride, 236. 
Chloroform, 441, 525. 
impurities in, 617. 
-water, 443. 
Chloroformum purification, 442. 
venale, 443. 
Chlorophyll, 486, 518. 
Chocolate, 465. 
Cholalic acid, 464. 
Cholate of sodium, 464. 
Cholesterin, 457, 516. 
Chondodendron tomentosum, 393. 
Chondrin, 459. 
Chondrus crispus, 407. 
Chromate of barium, 102. 
calcium, 113. INDEX 
Chromate of lead, 210. 
mercury, 236. 
potassium and ammonium, 
103. 
potassium, standard solution 
of red, 575. 
silver, 215. 
Chromates, 235. 
analytical reactions of, 235. 
of potassium, 103, 122, 236. 
Chrome-alum, 235. 
-ironstone, 234. 
-red, 210. 
-yellow, 210. 
Chromic acid, 235. 
anhydride, 235. 
hydrate, 235. 
salts, 235. 
Chromium, 234. 
analytical reactions of, 236. 
chloride, 235. 
derivation of word, 33. 
separation of, from aluminium 
and iron, 237. 
sulphate, 235. 
Cliromous salts, 236. 
Chromule, 486. 
Chrvsammic acid, 442. 
Chrysarobin, 335. 
Chrgsarobinum, 335. 
impurities in, 641. 
Chrysophanic acid, 335. 
Cicala virosa, 472. 
Cider, 427. 
Cimicifuga racemosa, 400. 
Cimicifugin, 400. 
Cinchamidine, 389. 
Cinchona assay, 616. 
Cinchona call saga, 383. 
flam, 383. 
officinalis, 383. 
pallichc cortex,, 383. 
rubra, 383. 
succirubra, 383. 
Cinchonia, 387. 
Cinchonicia, 383. 
Cinchonieine, 388. 
Cinchonidia, 387. 
Cinchonidine, 387. 
Cinchonidince sulphas, 388. 
impurities in, 644. 
Cinchonina, 388. 
impurities in, 644. 
Cinchonince sulphas, 387. 
Cinchonine, 387. 
Cinnabar, 191. 
Cinnamein, 482. 
Cinnamene, 482. 
Cinnamic acid, 334, 482. 
alcohol, 482. 
aldehyd, 472. 
Cinnamol, 483. 
Cinnamomum, 472. 
Cinnamon oil, 472. 
Cinnamyl, hydride of, 482. 
alcohol, 482. 
cinnamate of, 482. 
Citrate of ammonium, 93. 
calcium, 320. 
iron, 151. 
and ammonium, 151. 
and strychnine, 151. 
and quinine, 151, 626. 
lithium, 223. 
magnesium, 118. 
nicotia, 397. 
potassium, 72. 
volumetric estimation of, 
561. 
quinine, 384. 
silver, 323. 
Citrates, 72, 320. 
analytical reactions of, 323. 
volumetric estimation of, 560, 
561. 
Citric acid, 320. 
action of heat on, 324. 
saturating power of, 322. 
Citrine ointment, 196. 
Citronella oil, 472. 
Citronellol, 472. 
Citro-tartrate of sodium, 86. 
Citrus, 472. 
Citrus bergamia, 320. 
Classification of elements, 100, 121, 
124, 255. 
Clausius’s theory, 24. 
Claviceps purpurea, 478. 
Clay, 135. 
ironstone, 139. 
Cloves, oil of, 472. 
Club-moss, 466. 
Coal, 237. 
products of, 438. 
Coal-gas, 438. 
for balloons, 23. 
-tar colors, 487. 
Cobalt, 230. 682 
INDEX. 
Cobalt, analytical reactions of, 
230. 
arsenide, 230. 
blue, 486. 
derivation of word, 33. 
-glance, 230. 
hydrate. 230. 
separation of, from nickel, 233. 
sulphate, 230. 
sulphide, 230. 
Cobaltic ultramarine, 486. 
Cobalticyanide of potassium, 231. 
of nickel, 231. 
Cobalticyanides, 237. 
Coca, 394. 
Cocaina, 394. 
Cocaine, 394. 
Cocculus indicus, 422. 
Coccus, 334. 
ilicis, 179. 
impurities in, 644. 
Cochineal, 334. 
Cocoa, 465. 
-butter, 465. 
-nibs, 465. 
-nut, 465. 
-nut oil, 465. 
Cocos nucifera, 465. 
Codamine, 380. 
Codeia or codeine, 380. 
Codeina, 380. 
impurities in, 644. 
Cod-liver oil, 466. 
Cohesion, 56. 
Coinage, copper, 187. 
gold, 241. 
silver, 213. 
Coke, 30. 
Colchicein, 394. 
Colchici comm, 394. 
radix, 394. 
semina, 394. 
Colchicia, 394. 
Colchicin, 394. 
Colchicine, 394. 
Colcothar, 485. 
Collection of gases, 16, 17. 
Collidine, 392. 
Collin, 633. 
Collodion, 410. 
Collodium, 410. 
flexile, 410. 
stypticum, 410. 
Cologne-water, 470. 
Colloid bodies, 633. 
Colocynthis, 418. 
Colocyntlnn, 418. 
Colopholic acid, 478. 
Colophonic acid, 478. 
hydrate, 478. 
Colophonine, 478. 
Colophony, 478. 
Coloring-matters, 484. 
Combination, chemical, 44, 46. 
by volume, 52. 
Combining proportions, 48, 194, 
283, 520, 582. 
Combustible, 22. 
Combustion, 22. 
analysis for carbon and hy- 
drogen, 611 et seq. 
for nitrogen, 615. 
definition of, 57. 
spontaneous, 155. 
supporters of, 22. 
Composition of atmosphere, 26. 
bismuth salts, 249. 
oils and fats, 462. 
Compound, chemical, 37. 
different from mechan- 
ical, 36. 
definition of, 57. 
Compounds, 13, 36. 
of the elements, 60. 
Conchinine, 386. 
Condensation, 125. 
Condenser, 125. 
Condensing-tub, 125. 
-worm, 125. 
Condy’s disinfecting fluids, 76, 228. 
Confections, 517. 
Conhydrine, 395. 
Conia, conine, or conicine, 394, 395. 
Coniurn, 395. 
mnculatum, 395. 
Conquinine, 386. 
Constant proportions, law of, 47. 
Constitution of alkaloids, 377. 
matter, 41. 
salts, 52, 120, 260, 283, 296, 
375. 
visible matter, 30, 42. 
Construction of formulae, 41, 45, 62, 
63, 408. 
Convolvulin, 418. 
Convolvulinol, 418. 
Convolvulus scammonia, 424. • 
Conylia, 394. INDEX. 
683 
Copaiba, 480. 
impurities in, 480, 644. 
Copaiva, 480. 
oil, 480. 
Copaivic acid, 480. 
Copal, 478. 
Copper, 187. 
acetate, 189. 
ammonio-sulphate, 173, 189, 
203. 
analytical reactions of, 189, 
495. 
antidotes to, 190. 
arseniate, 173. 
arsenical, 169. 
arsenite, 173. 
black oxide, 188, 
blue, 487. 
coinage, 187. 
derivation of word, 32. 
detection of arsenicum in, 173. 
foil, 188. 
hydrate, 190. 
iodide, 272. 
in organic mixtures, detection 
of, 494. 
melting-point of, 527. 
metallic, 187. 
oxide, 188. 
oxyacetate, 188. 
pyrites, 187. 
quantitative estimation of, 594. 
quantivalence of, 187. 
subacetate, 188. 
sulphate, 188. 
anhydrous, 188. 
sulphide, 188. 
Copperas, blue, 141. 
green, 141. 
Coptis trifolia, 393, 
Coriander oil, 472. 
Coriandrum, 472. 
Com-smut, 478. 
Cork, sp. gr. of, 547, 
-borers, 16. 
Comic acid, 335. 
Comin, 335. 
Cornus, 335. 
florida, 335. 
Corpse-fat, 459. 
Correction of the volume of a gas 
for pressure, 547. 
for temperature, 547. 
Corrosive sublimate, 197, 202. 
Corrosive sublimate, test for, in 
calomel, 199. 
Corvclalia, 395. 
Corydalina, 395. 
Cotamine, 380. 
Coto-bark, 418. 
Cotoin, 418. 
Cotton-root bark, 479. 
Cotton-seed oil, 466. 
Cotton-wool, 409. 
Couch-grass, 401. 
Cow-bane, 472. 
Cowhage, 238. 
Cow’s milk, 457. 
Cranesbill, spotted, 356. 
Cream, 458. 
of tartar, 315. 
Creasol, 449. 
Creasote, 449. 
Creasotum, 449. 
impurities in, 644, 
Cresol, 440. 
Cresotie acid, 451. 
Cresylic acid, 449. 
Creta pneparata, 110. 
impurities in, 644. 
Crinum asiaticum, 425. 
Crocin, 485. 
Crocus (mineral), 150. 
(vegetable), 485. 
Crocus sativus, 484. 
Croton chloral, 445. 
oil, 466. 
Crucibles, 68. 
Crude antimony, 176, 
potashes, 61. 
Crum’s test for manganese, 230. 
Cryohydrates, 84. 
Cryolite, 373. 
Cryptophanic acid, 504. 
Cryptopia, 380. 
Crystallization, water of, 84. 
Crystalloid bodies, 633. 
Cubeba, 397. 
Cubebene, 472. 
Cubebin, 472. 
Cubeb pepper, 397. 
Cubebs, oil of, 472. 
Cubic inches in one gallon, 548. 
Cubic nitre, 282. 
Cuca (see Coca). 
Cucurbiia pepo, 401. 
Culver’s root, 401. 
Cumin, 472. 684 
INDEX, 
Cuminic acid, 472. 
Cuminol, 472. 
Cumin urn, 472. 
cyminum, 472. 
Cummin, 472. 
Cupel, 599. 
Cupellation, estimation of silver 
by, 599. 
Cupr-diammon-diammonium, sul- 
phate of, 203. 
Cupreine, 388. 
Capri acetas, 189. 
impurities in, 644. 
sulphas, 188. 
impurities in, 645. 
Cupric arsenite, 173, 190. 
compounds, 189. 
ferrocyanide, 190. 
hydrate, 190. 
oxide, 188. 
sulphate, 188. 
sulphide, 188. 
Cuprous iodide, 187, 272. 
oxide, 188, 411. 
Cuprum ammoniatum, 189. 
Curapoa, 427. 
Curarine, 390. 
Curcuma lonya, 485. 
Curcumin, 485. 
Curds, 412, 457. 
and whey, 412, 457. 
Curd-soap, 464. 
Currant, 320, 345, 411. 
Curry-powder, odor and flavor of, 
475. 
Cuspnrm cortex, 400. 
Cusparin, 400. 
Cusso, 479. 
Cutch, 355. 
Cyanates, 335. 
Cyanic acid, 335. 
Cyanide of allyl, 453. 
mercury, 276. 
nickel, 232. 
potassium, 276. 
silver, 215. 
Cyanides, 275. 
analytical reactions of metal- 
lic, 279. 
antidote to, 280. 
double, 276. 
quantitative estimation of, 
568. 
Cyanogen, 276, 280. 
Cyanurets (vide Cyanides). 
Cydonium, 406. 
Cymene, 472. 
Cymol, 472. 
Oypripedium pubescens, 400. 
Cystin, 508. 
Dahlia, 404. 
Dalton’s atomic theory, 50. 
law, 48, 49. 
Dandelion, 401. 
Danglish’s bread, 411. 
Daphne laureola, 479. 
mezereum, 418, 479. 
Daphnetin, 418. 
Daphnin, 418. 
Datura alba, 396. 
stramonium, 396. 
Daturia or daturine, 396. 
Davy’s safety-lamp, 23. 
Davyum, 660. 
Deadly nightshade, 392. 
Decantation, 107. 
Decimal coinage, 530. 
weights, 530, 533. 
Decipium, 660. 
Decoctions, 517. 
Decolorizing power of animal char- 
coal, 110. 
Decrepitation, 368. 
Definition of chemical action, 36. 
a chemical compound, 57. 
a chemical equation or dia- 
gram, 57. 
a chemical symbol, 57. 
a gas, 58. 
a liquid, 57. 
a mixture, 57. 
an atom, 57. 
an element, 57. 
a solid, 57. 
atomic weights, 58. 
chemical force, 56. 
chemistry, 56. 
combustion, 57. 
law of diffusion, 57. 
molecular weights, 58. 
quantivalence of atoms, 58. 
Deflagrating flux, 373. 
Deflagration, 74. 
Deliquescence, 86. 
Delphine, 395. 
Denarcotized opium, 379. 
Density, 542. INDEX. 
685 
Density of vapors, 548. 
Dentifrices, action of, 238. 
Deodorizers, 29. 
Deodorizing liquid, 130. 
Deposits, urinary, 506. 
Derivation of names of elements, 
31 et seq. 
Derivatives of ammonium, 203. 
Desiccation, 583, 606. 
Destructive distillation, 126. 
Detonation, 74. 
De Yalangin’s solution, 165. 
De Vrij’s process for estimating 
the value of cinchona-bark 
and the purity of commer- 
cial quinine, 618. 
Dextrin, 405. 
maltose, 411. 
Dextro-racemic acid, 317. 
Dextrose, 411. 
Dextro-tartaric acid, 317. 
Dliak tree, 355. 
Dhatura, 396. 
Diabetic urine, 504. 
Diagram, chemical definition of, 
57. 
Diagrams, chemical, 46, 47, 63, 64, 
69. 
Dialysate, 633. 
Dialysis, 633. 
Dialytic iron, 634. 
Dialyzed iron, 634. 
Diamines, 378. 
Diamond, 29. 
Diastase, 405. 
Dibasic acids, 260. 
Dibasylous radicals, 260. 
Dicentra formosa, 395. 
Didyinium, 660. 
Diethylamine, 377. 
Diethylia, 377. 
Diff'usate, 633. 
Diffusion, 24. 
law of, definition of, 57. 
Digitalein, 419. 
Digitalin, 418. 
J)igit(dinum, 418. 
Digitaliretin, 418. 
Digitalis, 418. 
Digitonin, 419. 
Digitoxin, 419. 
Dill oil, 471. 
Dinitrobenzol, 449. 
Dinitrocellulin, 409. 
Diosphenol, 472. 
Diospyros embiyopteris, 356. 
Dipterocarpus Icevis, 485. 
twbinatus, 480. 
Disinfectant, chlorine as a, 29. 
Disinfectants, 29. 
Disinfecting fluid, Barnett’s, 130. 
carbolic acid, 449. 
Condy’s, 76, 228. 
powder, 111. 
Dissociation, 550. 
Distillation, 124. 
destructive, 126. 
dry, 126. 
fractional, 426. 
Distilled vinegar, 295. 
Disulphide of carbon, 310. 
Dita, 395. 
Ditain, 395. 
Ditamine, 395. 
Dithionic acid, 343. 
Dock, 335. 
Dolomite, 115. 
Donovan’s solution, 163. 
Dorema ammoniacum, 481. 
Double chloride of aluminium and 
sodium, 135. 
cyanides, 276. 
salts, 78. 
Dover’s powder, 395. 
Drachm, 538. 
Draconyl, 483. 
Dragon’s blood, 478. 
Dried alum, 137. 
Drops, 538. 
Dry distillation, 126. 
Drying apparatus, 583, 585, 606. 
oils, 466. 
precipitates, 582, 584, 588, 606. 
Dryobfilanops aromcitica, 476. 
Duboisia, 396. 
myoporoides, 396. 
Dulcamara, 398. 
Dulcamarin, 398. 
Dulong and Petit’s law, 550. 
Dyads, 121. 
Dyer’s saffron, 485. 
Dyeing, 137, 287. 
by mordants, 137. 
Dynamic electricity, production of, 
129. 
Dynamicity, 56. 
Earth, alkaline, 124. INDEX, 
Earth, bone-, 109. 
-nut oil, 467. 
Earthenware, 351. 
Eau-de-Cologne, 470. 
Ebonite, 583. 
Ebullition, 277. 
Ecballium elaterium, 419. 
Ecboline, 478. 
Echites scholaris, 395. 
“ Effervescing citrate of magnesia,” 
_ 118. 
citro-tartrate of sodium, 86. 
potash-water, 71, 585. 
soda-water, 85. 
Efflorescence, 86. 
Egg, oil of, 456. 
white of, 456. 
yolk of, 456. 
Elfeometer, 544. 
Elseoptens, 469. 
Elaterinum, 419. 
impurities in, 645. 
Elaterium, 419. 
Elder-flower oil, 474. 
Elecampane, 404, 473. 
Electricity, production of dynam- 
ic/129. 
related to chemical action, 
550. 
Elementary particles, 37. 
Element, definition of, 57. 
Elements, 13, 14, 30. 
and their compounds, 59. 
classification of, 100, 121, 124, 
255. 
according to analogy, 
100. 
according to quantiva- 
lence, 120. 
etymology of names of, 30. 
of medical or pharmaceutical 
interest, 14. 
metallic, 15. 
non-metallic, 15. 
of pharmaceutical interest, 14. 
symbols of, 31, 46. 
atomic values and weights 
of the, 635. 
of, and derivation of 
names of, 31 e< seq, 
Elemi, 480. 
Elixirs, 517. 
Elm, common, 407. 
mucilage, 407. 
Elm, slippery, 407. 
-tannin, 355. 
Emetia, 395. 
Emetine, 395. 
Empirical formula?, 428. 
Emplastra, 517. 
Emplastrum plumbi,, 209. 
Emulsin, 416. 
Emulsion, 482. 
Enemas, 507. 
English red, 485. 
blue, 486, 
Epsom salt, 115. 
Equation, chemical, definition of, 
57. 
Equations, 57. 
Equisetie acid, 322. 
Equivalence, 56. 
Equivalents, 635. 
Erbium, 660. 
Ergot, 47-8. 
Ergota, 478. 
Ergotin, 478. 
Ergotine, 478. 
Ergotinine, 478. 
Ericolin, 417. 
Erigeron canadense, 473. 
Erlangen blue, 486. 
Erucic acid, 467. 
Erythroretine, 335. 
Erythroxylon, 394. 
coca, 394. 
Esculin {see iEsculin). 
Eseria, 397. 
Essence of aniseed, 471. 
apple, 446. 
greengage, 446. 
melon, 446. 
mirbane, 448. 
mulberry, 446. 
peppermint, 473. 
pineapple, 446. 
quince, 446. 
j Essences, 446. 
| Essentia anisi, 471. 
menthce piper itce, 473. 
Essential oils (vide Oils). 
Estimation of weight, 528. 
Etching, 339. 
Ethal, 465. 
Ether, 432. 
nitrous, 434. 
| Ethereal salts, 438. 
oil, 453. INDEX, 
687 
Etherol, 453. 
Ethers, 432, 438. 
Ethiops mineral, 203. 
Ethyl, 428, 436. 
acetate, 436. 
bromide, 436. 
butyrate, 446. 
hydrate, 425. 
hydride, 438. 
iodide, 436. 
nitrite, 434. 
cenanthylate, 446. 
oxide, 432. 
pelargonate, 443. 
sebaeate, 446. 
suberate, 446. 
sulphate, 428. 
zinc, 437. 
Ethylamine, 377. 
Ethylate of sodium, 428. 
Ethylene, 453. 
Ethylia, 377: 
Ethylic alcohol, 428. 
Etymology of names of elements, 31. 
Eucalyptol, 473. 
Eucalyptus, 473. 
globulus, 473. 
Euchlorine, 292. 
Eudiometry, 491. 
Eugenic acid, 472. 
Eugenin, 472. 
Euodic aldehyd, 474. 
Euonymin, 400. 
Euonymus atropurpureas, 400. 
Eupatorium, 400. 
Euphorbiurn, 481. 
Euphorbon, 481. 
Euxanthate of magnesium, 484. 
Evaporation, 70, 100, 583, 584. 
in vacua, 583. 
Everitt’s yellow salt, 278. 
Examinations of the Pharmaceut- 
ical Society of Great Brit- 
ain, 14 (vide prefatory mat- 
ter). 
Expansion on diluting solution of 
ammonia, 91. 
Explosions of gases, 22. 
Extract of malt, 406. 
Extracts, 517. 
E.ctractum glycyrrhizce, 421. 
fluidum, 431. 
pur urn, 421, 
Saturni, 208. 
Face-rotjge, 334, 48(5. 
Faeces, 503. 
Fahrenheit’s thermometer, 523. 
Farina triiici, 401. 
Fat-acids, 465. 
Fats and oils, composition of, 
462. 
Fats, etc., to determine the melt- 
ing-point of, 526. 
analysis of, 635. 
Fatty bodies, 462. 
Fehling’s solution, 630. 
Fel bovis, 464. 
inspissatum, 464. 
purification, 464. 
impurities in, 645. 
Felspar, 373. 
Fennel oil, 473. 
Fermentation, 412. 
alcoholic, 428. 
ammoniacal, 426, 505. 
butyric, 426. 
lactic, 426. 
mannitic, 426. 
putrefactive, 426. 
viscous, 426. 
Fer recluit, 155. 
Ferrate of potassium, 140. 
Ferri acetatis, liquor, 147. 
tinctura, 147. 
arsenias, 142. 
bromidi, syrupus, 144. 
carbonas, 141. 
saccharatus, 142. 
impurities in, 645. 
chloridi, liquor, 146. 
chloridum, 146. 
impurities in, 645. 
citras, 151. 
citratis, liquor, 151. 
et ammonii citron, 151. 
impurities in, 645. 
quantitative estimation of 
iron in, 592. 
sulphas, 136. 
impurities in, 645. 
tartras, 152. 
impurities in, 645. 
et potassii tartras, 152, 320. 
impurities in, 645. 
et quinince citras, 151. 
impurities in, 645. 
liquor, 153. 
et strychnines citras, 151. 688 
INDEX 
Ferri et strychnines citras, 151. 
impurities in, 645. 
hypophosphis, 342. 
impurities in, 645. 
iodidum, 144. 
saccharatum, 144. 
impurities in, 645. 
laclas, 345. 
impurities in, 645. 
nitratis, liquor, 154. 
oxalas, 313. 
oxidum hydratum, 148. 
cum magnesia, 148. 
magneticum, 153. 
perchloridi, liquor, 146. 
peroxidum hydra,him, 148. 
phosphas, 142, 152. 
potassio-tartras, 152. 
pulv is, 155. 
pyrophosphas, 156. 
subsulphatis, liquor, 147. 
sidphas, 140, 577. 
impurities in, 645. 
exsiccatus, 141. 
prcecipitatus, 141. 
impurities in, 645. 
tersulphalis, liquor, 147. 
valerianas, 359. 
Ferric acetate, 147. 
chloride, 144. 
citrate, 151. 
hydrate, 148. 
hypophosphite, 342. 
iodate, 293. 
nitrate, 154. 
oxide, 150. 
from phosphates and ox- 
alates, separation of, 
371. 
oxyiodate, 293. 
oxysulphate, 141. 
peroxy hydrate, 148. 
phosphate,-152, 328. 
pyrophosphate, 156. 
salts, 144. 
analytical reactions of, 
158. 
sulphate, 147. 
sulphocyanate, 158. 
tartrate, 152. 
valerianate, 359. 
Ferricyanogen, 158, 339. 
Ferridcyanide of potassium, 158, 
276, 339. 
Ferridcyanides, 339. 
Ferrocyanide of potassium, 158, 
27(5, 339. 
of zinc, 134. 
Ferrocvanides, 337. 
Ferrocyanogen, 158, 337. 
Ferro-ferric hydrate, 153. 
oxide, 153. 
Ferrous arseniate, 142, 576. 
bromide, 144. 
carbonate, 142, 576. 
chloride, 145. 
hydrate, 157. 
iodide, 144. 
phosphate, 142. 
salts, 140. 
analytical reactions of, 
157. 
sulphate, 140, 577. 
sulphide, 143, 157. 
Ferrum, 32, 139. 
redactum, 155, 592. 
impurities in, 645. 
tartaratum, 320. 
estimation of iron in, 592. 
Ferula narthex, 481. 
sumbul, 48l. 
Ferulaic acid, 481. 
Fibrin, 456. 
vegetable, 459. 
Ficus, 411. 
elastica, 483. 
Fig, 411. 
Filicic acid, 467. 
Filter, to dry, 582. 
Filtering-paper, 106, 582. 
Filters, 106, 582. 
Filtrate, 122. 
Fine gold, 241. 
Fire-clay, 197. 
Fire-damp, 438. 
Fixed and volatile oils, difference 
between, 466. 
Fixed oils, 468. 
Flame, structure of, 23. 
Flaxseed, 466. 
Fleabane, 473. 
Fleitmann’s test for arsenicum, 
171. 
Flexible collodion, 410. 
Flint, 351. 
Flores zinci, 132. 
Flour, 401. 
Flowers of sulphur, 298. INDEX. 
689 
Fluid magnesia, 117. 
Fluoride of boron, 330. 
calcium, 103. 
in bones, 109, 340. 
silicon, 340. 
Fluorides, 339. 
Fluorine, 340. 
derivation of word, 33. 
Fluor-spar, 340. 
Fveniculiun, 473. 
Foil, copper, 187. 
Food, analysis of, 635. 
elements of, 459. 
how disposed of in the bodies 
of animals, 503. 
Force, chemical, 37. 
Forge-scales, 153. 
Formates, 336. 
Formic acid, 335, 468. 
Formica rufa, 335. 
Formula, chemical, definition of, 
57. 
- official, 28. 
officinal, 28. 
Form u he, 41, 45, 615. 
construction of, 55, 62. 
empirical, 428, 616. 
graphic, 135. 
rational, 428, 615. 
typical, 377. 
Formyl, 442. 
Fousel oil, 445. 
Fowler’s solution, 164. 
Foxglove, 419. 
Fractional distillation, 426. 
Frangula, 418. 
Frankincense, Arabian, 482. 
common, 481. 
Frankland’s graphic formulae, 135. 
Fraxinus ornus, 415. 
Free acids estimated, 563. 
Freezing-mixture, 302. 
French chalk, 487. 
turpentine, 475. 
Fruit-essences, 446. 
Fuchsine, 481. 
Fume-cupboard, 99. 
Fuming sulphuric acid, 307. 
Funnel-tubes, 23, 96. 
“Fur” in water-vessels, 312. 
Furniture of a laboratory, xii. 
Fusel oil, 445. 
Fusibility of metals, Table of the, ! 
527. 
Fusible white precipitate, 202. 
Fusing-points of fats, 526. 
Fustic, 484. 
Gab tree, 356. 
Galactometer, 544. 
Galactose, 413. 
Galbanum, 482. 
Galena, 206. 
argentiferous. 212. 
Galenical preparations of the Brit- 
ish Pharmacopoeia, 517. 
Galipot, 478. 
Gall, of the ox, 464. 
Gal la, 354. 
Gallic acid, 356. 
Gallium, 660. 
Gallon, 530. 
Galls, Aleppo, 354. 
English, 354.- 
Gall-stones, 516. 
Galvanic test for mercury, 204. 
Galvanized iron, 128. 
Gambier, 355. 
Gamboge, 481, 484. 
Gambogic acid, 481. 
Garancin, 485. 
Garcinia Hanburii, 481. 
Garcinia incHca, 466. 
oil, 466. 
morella, 481. 
pictoria, 481. 
purpurea, 466. 
Garden thyme, 475. 
Garlic, essential oil of, 453. 
Gas, a definition of, 57. 
analysis, 357, 491. 
-burners, 16, 23. 
for balloons, coal-, 23. 
illuminating, 438. 
-lamp, 18, 23. 
Gases and vapors, density of, 522, 
548. 
collection of, 16, 19. 
correction of the volume of, 
548. 
for pressure, 548. 
for temperature, 548. 
diffusion of, 24. 
law of solubility of, in liquids, 
85. 
relation of, to liquids and 
solids, 43, 44. 
specific gravity of, 548. 690 
INDEX. 
Gastric juice, 460. 
artificial, 460. 
Gaultheria procurtibens, 446 
Gaultheric acid, 446. 
Gay-Lussac’s law, 52 
Gelatin, 459. 
sugar, 464. 
vegetable, 407. 
Gelatinized starch, 404. 
Gelatinous substances, 459. 
Gelseminia, 396. 
Gelseminic acid, 396. 
Gelsemium, 396. 
Gentian-hitter, 420. 
Gentiana lutea, 420. 
Gentiance radix, 420. 
Gentianic acid, 420. 
Gentiogenin, 420. 
Gentiopicrin, 420. 
Gentisic acid, 420. 
Gentisin, 420. 
Geraniol, 473. 
Geranium maculatum, 356. 
German silver, 232. 
Gin, 427. 
Gingelly oil, 467. 
Ginger oil, 475. 
-grass oil, 473. 
Girdwood and Rogers’s method for 
detecting strychnine, 498. 
Glacial acetic acid, 296, 526. 
phosphoric acid, 327. 
Glass, 351. 
liquor, 352. 
rods, 108. 
soluble, 352. 
tubes, to bend, 17. 
to cut, 17. 
to draw out, 108. 
Glauber’s salt, 264. 
Globulin, 457. 
Glucinum, 680. 
Glucose, 411. 
Glucosides, 416. 
Glue, 460. 
Gluten and glutin, 401. 
Glyceric alcohol, 454. 
Glycerin, 209, 454. 
Glycerins, 453. 
Glycerinum, 455. 
impurities in, 645. 
Glyceritum, 455. 
amyli, 455. 
vitelli, 455. 
Glyceryl, 453, 462. 
caproate, 465. 
caprylate, 465. 
hydrate, 455, 462. 
hydrato-oxalate, 336. 
1 an rate, 465. 
myristate, 465. 
oleate, 462. - 
palmitate, 465. 
ricinoleate, 465. 
rutate, 465. 
tristearate, 462. 
Glycholates, 464. 
Glycocine, 464. 
Glycocoll, 464. 
Glycol, 453. 
Glycols, 453. 
Glycyl, 454. 
Glycocin, 455. 
Glycyrretin, 421. 
Glycyrrhiza, 421. 
Glycyrrhizate of ammonium, 421. 
lime, 421. 
Glycyrrhizin, 421. 
Glycyrrhizinum ammonialum, 421. 
Gnoscopine, 380. 
Goa powder, 335. 
Gold, 241. 
and sodium chloride, 242. 
analytical reactions of, 242. 
coin, 241. 
derivation of word, 34. 
earth, 241. 
fine, 241. 
jewellers’, 241. 
leaf, 241. 
mosaic, 240. 
ochre, 484. 
perch lor ide, 242. 
sulphide, 242. 
yellow, 484. 
Golden seal, 393. 
Goldthread, 393. 
Gooseberry, 320, 345. 
Gossypium, 409. 
impurities in, 646. 
radicis cortex, 479. 
Gothite, 149. 
Goulard’s cerate, 208. 
extract, 208. 
water, 208. 
Gracillaria, 407. 
Graham’s dialvtic process, 633. 
law of diffusion, 24. Grains, 529. 
of paradise, 473. 
Gramme, 532. 
relation of, to grains, 534, 535. 
Granati cortex, 355. 
Grunatum, 355. 
Granite, 135. 
Granulated phosphorus, 325, 
citrate of magnesium, 118. 
tin, 238. 
zinc, 20. 
Granulose, 405. 
Grape, 345, 412. 
Grapes, dried, 412. 
Grape-sugar, 411. 
Graphic formulae, 135. 
Graphite, 29. 
Grass oil, 472, 475. 
Gravel, 506. 
Gravimetric analysis, 520, 581. 
Gravitation, 528. 
Gravity, 528. 
Gray powder, 195. 
Green copperas, 141. 
chloride of iron, 144. 
iodide of iron, 144. 
of mercury, 193. 
pigments, 486. 
soap, 463, 464. 
sulphate of iron, 140. 
vitriol, 141. 
Greengage essence, 446. 
Griffith’s mixture, 142. 
Grindelia, 400. 
Groundnut oil, 467. 
Group tests, 220. 
Guaiaci lignum, 421. 
resince, 421. 
Guaiacin, 421. 
Guaiacol, 449. 
Guaiaconic acid, 421. 
Guaiacum, resin of, 421. 
Guaiaretic acid, 421. 
Guaiaretin, 421. 
Guaiaretinic acid, 421. 
Guano, 358. 
Guarana, 398. 
Guilandina bonducella, 400. 
Guinea grains, 473. 
Gulancha, 400. 
Gum, 407. 
-acacia, 112. 
-arabic, 112. 
British, 405. 
INDEX. 
Gam, cherry-tree, 407. 
-resins, 481. 
-tragacanth, 112, 407. 
Gummate of calcium, 112, 407. 
lead, 112. 
Gummic acid, 407. 
Gun-cotton, 410. 
-metal, 238. 
-powder, 287. 
Gurjun balsam, 480. 
Gutta percha, 483. 
Guttae, 538. 
Gynocardia odorata, 400. 
Gypsum, 103. 
II.ematein, 487. 
Haematite, brown, 138. 
red, 138. 
Hinnaloxylon, 355, 486. 
Haematoxvlin, 355, 486. 
Half-sovereign, weight of the, 242. 
Haloid salts, 284. 
Hamamelis, 400. 
Hambro’ blue, 487. 
Hardness of water, 312. 
Hard soap, 464. 
Heat, latent, 84. 
related to chemical action, 550. 
source of, 21. 
Heavy carbonate of magnesium, 
116. 
magnesia, 118. 
spar, 101. 
white, 101, 487. 
Heberden’s ink, 158. 
Hectare, 532. 
Hedeoma, 400. 
Helenin, 473. 
Hellebore, black, 421. 
green, 421. 
white, 421. 
American, 396. 
Helleborein, 421. 
Helleborin, 421. 
Helleborus niger, 421. 
viridis, 421. 
Ilemidesmi. radix, 336. 
Hemidesmic acid, 336. 
Hemlock, 394. 
pitch, 481. 
Hemp, Canadian, 400. 
Indian, 478. 
Hempseed calculi, 516. 
Henbane, 396. 692 
INDEX. 
Henry and Dalton’s law, 85. 
Herapathite, 385. 
Hesperidene, 471. 
Hevea Braziliensis, 483. 
Heterologous series, 438. 
Hexyl, 438. 
Hi b iscus esculentus, 407. 
High blackberry, 356. 
Hippuric acid, 336, 508, 511. 
Hips, 414. 
Hoffmann’s anodyne, 434. 
Hofiher’s blue, 487. 
Homologous series, 438, 468. 
Homoquinine, 388. 
Honey, 414. 
dew, 414. 
Hop, 481. 
essential oil of, 481. 
Hordeum decorticatum, 402. 
starch of (fig.), 403. 
Horehound, 401. 
Horsemint, 475. 
Horseradish oil, 438, 471. 
Hubbuck’s oxide of zinc, 132. 
Humulus lupulus, 481. 
Hydrargyri chloridum corrosivum, 
i 97. 
impurities in, 646. 
mile, 198. 
impurities in, 646. 
cyanidum, 276. 
impurities in, 646. 
iodidum rubrum, 191. 
impurities in, 646. 
viride, 193. 
impurities in, 646. 
nilrati acidus, liquor, 198. 
nitratis liquor, 196. 
oxidum flavum, 200. 
rubrum, 199. 
impurities in, 646. 
perchloridum, 197. 
subchloridum., 198. 
subsulphas flavus, 197. 
impurities in, 646. 
sidphas, 196. 
impurities in, 646. 
sulphuretum cum sulphure, 203. 
sulphidum rubrum, 203. 
impurities in, 646. - 
unguentum, 191. 
Hydrargyrum, 33, 191. 
impurities in, 618. 
ammoniatum, 202. 
Hydrargyrum ammoniatum, impur- 
ities in, 646. 
cum, crela, 191. 
Hydrastia, 393. 
Hydrastis canadensis, 393. 
Hydrated peroxide of iron, 148. 
substances, 84. 
Hydrate of aluminium, 137. 
ammonium, 90. 
benzoyl, 334. 
cadmium, 245. 
calcium, 106. 
cetyl, 465. 
chromium, 236. 
cobalt, 230. 
glyceryl, 455. 
manganese, 229. 
nickel, 232. 
potassium, 61. 
sodium, 81. 
zinc, 134. 
Hydrates/composition of, 65, 81. 
identified, 375. 
Hydraulic cement, 351. 
Hydric acetate, chloride, nitrate, 
sulphate, etc. (vide the respec- 
tive acids—Acetic, Hydrochlor- 
ic, etc.). 
Hydride of antimony, 181. 
arsenicum, 170. 
benzoyl, 416, 482. 
cinnamyl, 482. 
copper, 342. 
ethyl, 438. 
methyl, 437. 
phosphorus, 341. 
silicon, 352. 
Hydrides, 121, 438. 
Hydriodic acid, 269. 
Hydrium, 2ik, 
Hydrobromic acid, 265, 565. 
volumetric estim. of, 565. 
ether, 438. 
Hydrocarbons, 469. 
Hvdrochlorate of morphine, 385. 
Hydrochloric acid, 29, 262. 
analytical reactions of, 264. 
antidote to, 265. 
common, 262. 
dilute, 262. 
in organic mixtures, detection 
of, 495. 
volumetric estimation of, 565. 
Hydrocotarnine, 380. INDEX. 
Hydrocotyle asiutica, 400. 
Hydrocyanic acid, 275. 
analytical reactions of, 279, 
496. 
antidotes to, 230. 
dilute, 277. 
from bitter almond and cher- 
ry laurel, 417. 
in organic mixtures, detection 
of, 495. 
in the blood, 280. 
Schonbein’s test for, 280. 
volumetric estimation of, 567. 
Hydroferrideyanic acid, 333. 
Hydroferrocyanie acid, 337. 
Hydrofluoric acid, 337. 
Hydrogen, 20. 
antimoniuretted, 187. 
arseniuretted, 173. 
benzoate, borate, etc. (vide 
the respective acids—Ben- 
zoic, Boracic, etc.), 
combustion of, 21. 
derivation of word, 31. 
explosion of, 22. 
functions of, 121. 
in artificial light-producers, 
22. 
lightness of, 23. 
peroxide, 102. 
persulphide, 299. 
phosphoretted, 311. 
preparation of, 20. 
properties of, 21. 
quantitative estimation of, in 
organic compounds, 611 et 
seq. 
salts of, 260. 
siliciuretted, 352. 
sulphuretted, 95, 295. 
type, 377. 
used for balloons, 23. 
weight compared with air, 24. 
of 1 litre, 548. 
of 100 cubic inches, 548. 
Hydrogenium, 20. 
Hvdroquinone, 417, 450. 
Hyd rometers, 544. 
Hydrosulphuric acid, 298. 
Hydrosulphyl, 299. 
Hydrous chloral, 443. 
compounds, 84, .121. 
Hydroxyl, 299. 
H yoscyamia, 396. 
Hyoscyamus, 396. 
H yoscine, 396. 
Hyoseyamince sulphas, 396. 
impurities in, 646. 
Hyoscyamine, 396. 
Hyper-, meaning of, 145. 
Hypo-, meaning of, 312. 
Hypobromites, 268. 
Hypochloride of sulphur, 301. 
Hypochlorite of calcium, 111. 
sodium, 86. 
Hypochlorites, 289. 
Hypochlorous acid, 289. 
Hypopliosphite of calcium, 341. 
iron, 342. 
magnesium, 341. 
potassium, 341. 
sodium, 341. 
Ilypophosphites, 342. 
syrup of, 342. 
Hypophosphoric acid, 349. 
Hypophosphorous acid, 340. 
Hyposulphite of calcium, 300. 
sodium, 342. 
standard solution of, 578. 
Hyposulphites, 342. 
Hyposulphurous acid, 342. 
-ic, meaning of, 75, 140. 
Icacin, 480. 
Iceland moss, 335. 
Ichthyocolla, 459. 
impurities in, 646. 
- ids, meaning of, 75. 
Igasurine, 390. 
Iynatia, 388. 
Ignition, 100. 
lllicium anisatum, 471. 
Illuminating agents, analysis, 635. 
Incense, 482. 
Inch, 538. 
Incineration, 100. 
of filters in quantitative analy- 
sis, 582, 588. 
Indelible ink, 214. 
India-rubber, 483. 
vulcanized, 483. 
Indian barberry, 393. 
cannabis, 478. 
corn-smut, 478. 
gamboge, 481. 
hemp, 478. 
ink, 487. 
ipecacuanha, 395. 694 
INDEX. 
Iodide of silver, detection of chlo- 
ride in, 271. 
starch, 405. 
sulphur, 271. 
Iodides, 270. 
analytical reactions of, 271. 
of mercury, 193, 204. 
quantitative estimation of, 601. 
separation of, from bromides 
and chlorides, 273. 
Iodine, 30, 269. 
chloride, 270. 
derivation of word, 31. 
its analogy to chlorine and 
bromine, 269. 
solution of, 271, 579. 
standard solution of, 579. 
test of purity, 269. 
tincture of, 171, 580. 
volumetric estimation of, 579. 
-water, 271. 
Iodized starch, 405. 
Iodoform, 429, 443. 
Iodoformum, 429, 443. 
impurities in, 646. 
Iodosulphate of chinoidine, 619. 
Iodum, 269. 
impurities in, 646. 
lodinium, 269. 
Ipecacuanha, 395. 
Ipomea orizabensis, 421. 
pur pa, 421. 
simulans, 421. 
turpethum, 197. 
Iridin, 400. 
Iridium, 245. 
Iris jiorentina, 473. 
versicolor, 400. 
Irish moss, 407. 
Irisin, 400. 
Iron, 138. 
acetate, 147. 
acetonitrate, 154. 
alum, 136. 
ammonio-eitrate, 151. 
-tartrate, 152. 
analytical reactions, 157. 
arseniate, 142, 167. 
volumetric estimation of, 
576. 
black hydrate, 153. 
oxide, 158. 
bromide, 144. 
carbonate, 141, 576. 
Indian mustard, 453. 
liquorice, 420. 
pennywort, 400. 
red, 485. 
yellow, 484. 
Indican, 287. 
Indiglucin, 287. 
Indigo, 287. 
sulphate of, 287. 
-blue, 287. 
-white, 287. 
wild, 400. 
Indigogen, 287. 
Indigotin, 288. 
Indium, 660. 
Infusible white precipitate, 202. 
Infusions, 517. 
Inhalation of chlorine, 28. 
coniine, 395. 
hydrocyanic acid, 279. 
Inhalations, 517. 
Injectio morphine hypodermica, 380. 
Ink, black, 158, 355. 
Heberden’s, 158. 
indelible, 214. 
Indian, 487. 
invisible, 231. 
marking, 214. 
printer’s, 487. 
sympathetic, 231. 
Inorganic chemistry, 375. 
compounds, 375. 
Insecticide, 479. 
Introduction, 13. 
Imda helenium, 404, 473. 
Inulic anhydride, 473. 
Inulin, 404. 
Inulol, 457. 
Inverted sugar, 411. 
lodal, 445. 
Iodate of potassium, 74, 293. 
Iodates, 293. 
Iodic acid, 293. 
Iodide of ammonium, 270. 
arsenicum, 163. 
bismuth and potassium, 502. 
cadmium, 246. 
ethyl, 436. 
hydrogen, 269. 
iron, 31, 144, 571. 
lead, 209. 
mercury and potassium, 194. 
potassium, 73, 571. 
silver, 215. INDEX. 
695 
Iron, cast, 139. 
chlorides, 144. 
citrates, 151. 
compounds, nomenclature of, 
140. 
derivation of word, 32. 
detection of, in presence of 
aluminium and zinc, 159. 
galvanized, 128. 
hydrated peroxide of, 148. 
hvpophosphite, 342. 
in official compounds, estima- 
tion of, 576, 592. 
iodate, 293. 
iodide, 30, 144, 559. 
lactate, 345. 
magnetic oxide, 153. 
estimation of iron in, 576. 
nitrate, 154. 
ore, magnetic, 138. 
needle, 149. 
spathic, 139. 
specular, 139. 
oxide of, 153. 
oxyhydrates, 148. 
oxysulphate, 141. 
perch lor ide, 146. 
perhydrate, 148. 
pernitrate, 154. 
peroxide, 150. 
peroxy hydrate, 148. 
persulphate, 146. 
phosphate, 142, 152, 328. 
volumetric estimation of, 
676. 
from phosphates and oxalates, 
separation of peroxide of, 
371. 
potassio-eitrate, 151. 
-tartrate, 152. 
protected from rust, 139. 
pyrites, 139. 
pyrophosphate, 156. 
quantitative estimation of, 576, 
592. 
and quinine, citrate of, 151, 
384. 
red oxide, 150. 
reduced. 155. 
rust, 139. 
saccharated carbonate, 142. 
volumetric estimation of, 
576. 
salts, nomenclature of, 140. 
Iron, scale compounds of, 150. 
separation of, from alumin- 
ium and chromium, 273. 
sodio-citrate, 151. 
-tartrate, 151. 
-stone, clay, 139. 
subcarbonate, 141. 
subsulphate, 147. 
sulphate, 141. 
volumetric estimation of, 
577. 
sulphide, 143. 
sulphocyanate, 158, 280. 
tartrate, 151. 
tersulphate, 147. 
wrought, 139. 
Isinglass, 459. 
Isomerides, 407. 
Isomerism, 407. 
Isomers, physical, 407. 
Isomorphism, the doctrine of, 54. 
Isomorplious bodies, 54, 330. 
Isortandra gnlta, 483. 
Ispaghul, 407. 
-ite, meaning of, 75. 
Ivory-black, 487. 
Jaborandi, 397. 
Jaborine, 397. 
Jalap, Mexican male, 422. 
resin, 422. 
Tampico, 422. 
true, 422. 
Jalapa, 422. 
Jala pee resina, 422. 
Jalapic acid, 422. . 
Jalapin, 422. 
Jalapinol, 422. 
James’s powder, 180. 
Japaconitine, 392. 
Jaune brilliant, 245. 
Jelly, 459. 
vegetable, 407. 
Jervia, 396. 
Jervine, 396. 
Juglandine, 396. 
Juglans, 396. 
Juices, 517. 
Juniper oil, 473. 
Juniper ax, 473. 
mbina, 473. 
Kaixit, 61. 
Kaladana resin, 422. INDEX. 
Kali, 32. 
Kalium, 31. 
Kamala, 479. 
Kaolin, 352. 
Kariyat, 400. 
Kelp, 269. 
Kermes mineral, 179. 
Kerner’s test for purity of sul- 
phate of quinine, 624. 
Kieserit, 115. 
Kilbride mineral, 149. 
Kiln, 105. 
Kilogramme, 532, 533. 
Kilolitre, 540. 
Kilometre, 532. 
Kinate of qninia, 383. 
Kinetic theory, 24. 
King’s blue, 487. 
Kino, 355. 
Kinone, 417. 
Kiwach, 238. 
Kokum butter, 465. 
Kola-nut, 398. 
Kooso, 479. 
Kosin, 479. 
Koussin, 479. 
Kousso, 479. 
Krameria, 355. 
Labarraque’s solution, 86. 
Laboratory furniture, xii. 
Lac, 457, 486. 
Lac-dye, 486. 
Lactates, 345. 
Lactic acid, 346, 565. 
volumetric estimation of, 565. 
Lactometer, 458. 
Lactophosphate of calcium, HO. 
Lactose, 412. 
Lacto-glucose, 413. 
Lactuca, 400. 
Lactucarium, 400. 
Lactucin, 400. 
Ladies’ slipper, 400. 
La;vogyrate, 411, 412. 
Lsevoracemic acid, 317. 
Laevorotation, 412. 
Lsevotartaric acid, 317. 
Laevulose, 411. 
Lakes, 137. 
Lampblack, 487. 
Lamps, gas-, 17, 23. 
Lana philosophica, 132. 
Lanthanum, 660. 
Lanthopine, 380. 
Lappa, 400. 
Larch-bark, 356. 
Lard, 464. 
benzoated, 464. 
oil, 464. 
prepared, 464. 
Laricis cortex, 356. 
Larix europcca, 474. 
Larixin, 356. 
Larixinic acid, 356. 
Latent heat, 84. 
Laudanine, 380. 
Laudanosine, 380. 
Laughing-gas, 92. 
Laurate of glyceryl, 465. 
Laurel-camphor, 476. 
Laurie aldehvd, 474. 
Laurie acid, 465, 468. 
Laurocerasi folia, 417. 
Lavandula, 470. 
Lavender oil, 470. 
-water, 470. 
Lavoisium, 660. 
Law, Avogadro’s and Ampere’s, 
52. 
Berthollet’s, 376. 
Boyle’s, 52. 
Charles’s, 52. 
of chemical combination by 
weight, 47 et seq., 58. 
by volume, 51 et seq., 5S. 
concerning molecular weight, 
54, 538. 
of constant proportions, 48, 
519, 582. 
Dalton’s, 47, 48. 
of diffusion, definition of, 57. 
Dulong and Petit’s, 550. 
Gay-Lussac’s, 50. 
Graham’s, 24. 
Henry and Dalton’s, 85. 
Malaguti’s, 376. 
Mariotte’s, 52. 
multiple proportions, 48, 194, 
286. 
reciprocal proportions, 48. 
solubility of gases in liquids, 
85. 
Laws of chemical combination, 
47, 52, 53. 
Lead, 206. 
acetate, 207. 
analytical reactions of, 210,494. INDEX. 
697 
Lead, antidotes to, 211. 
carbonate, 207. 
chloride, 210. 
chromate, 211. 
derivation of word, 32. 
gnmmate, 112. 
h yd rat o carbon ate, 207. 
in organic mixtures, detection 
of, 495. 
iodide, 209. 
nitrate, 208. 
oleate, 209. 
oxide, 208. 
oxyacetate, 208. 
oxychromate, 211. 
plaster, 209. 
puce-colored oxide or perox- 
ide of, 208. 
pyrophorus, 155. 
quantitative estimation of, 559, 
597. 
red, 208, 485. 
shot, 206. 
subacetate, 207. 
■ sugar of, 207. 
sulphate, 211. 
sulphide, 211. 
native, 206. 
test for, in water, 211. 
-tree, 211. 
volumetric estimation of solu- 
tions of acetate of, 559. 
-water, 208. 
white, 206. 
Leadstone, 138. 
Leaf-green, 486. 
Lecanora, 486. 
Lees, 315. 
Legumin, 459. 
Lemon-chrome, 210. 
-juice, 321. 
estimation of mineral 
acid in, 605. 
oil, 470. 
Length unit, 531. 
Lentisk tree, 479. 
Lepidolite, 223. 
Leptandra virginiea, 401. 
Leptandrin, 401. 
Levant wormseed, 423. 
Levisticum, 482. 
Levulose, 412. 
Lichen blue, 487. 
Lichenin, 404. 
Light carbonate of magnesium, 
116. 
carburetted hydrogen, 438. 
magnesia, 118. 
Lignin, 409. 
Lime, caustic, 105. 
bisulphite, 303. 
chloride of, 111. 
-juice, 321. 
estimation of mineral 
acid in, 605. 
-kiln, 105. 
oil, 470. 
quick-, 105. 
slaked, 105. 
superphosphate of, 324. 
volumetric estimations, 559. 
-water, 105. 
Limestone, 103. 
magnesian, 115. 
mountain, 115. 
Liman is cortex, 470. 
succus, 321. 
impurities in, 646. 
Limonite, 149. 
Line, 538. 
Liniment of mercury, 191. 
Liniments, 517. 
Linimenturn ammonia, 463. 
colds, 463. 
Linoxin, 466. 
Linseed, 466. 
cake, 466. 
oil, 466. 
tea, 407. 
Linum, 466. 
usitatissimum, 407. 
impurities in, 646. 
Liqueurs, 427. 
Liquidambar orientate, 483. 
Liquid camphor, 476. 
definition of, 57. 
Liquids, specific gravity of, 542. 
official, specific gravity of, 543. 
Liquor, acidi arseniosi, 165. 
ammonite cilratis, 93. 
ammonii acetatis, 91. 
impurities in, 646. 
antimonii chloridi, 177. 
estimation of anti- 
mony in, 594. 
arsenii. et hydrargyri iodidi,. 163. 
calc is, 105. 
impurities in, 647. 698 
INDEX 
Liquor, caleis chloratce, 112. 
impurities in, 647. 
Jerri acetutis, 147. 
impurities in, 647. 
chlnridi, 146. 
impurities in, 647. 
citratis, 151. 
impurities in, 647. 
et (j'linince. citratis, 151. 
estimation of iron in, 
592. 
nitratis, 154. 
estimation of iron in, 
592. 
impurities in, 647. 
subsulphatis, 147. 
impurities in, 647. 
tersulphatis, 147. 
estimation of iron in, 
592. 
impurities in, 647. 
guUa-perchce, 483. 
hydrargyri nitratis, 196. 
impurities in, 647. 
perchloridi, 198. 
iodi cornpositus, 276, 580. 
lit dice effervescent, 223. 
magnesive carbonatis, 117. 
magnesii citratis, 118. 
nwrpli ice acefatis, 380. 
hydrochloratis, 380. 
pepsini, 461. 
impurities in, 647. 
plumbi subacetatis, 208. 
dilutes, 208. 
poiassce, 61, 67. 
impurities in, 647. 
effervescent, 71. 
neutralizing power 
of, 556. 
specific gravitv of, 
543. 
to prepare pure, 67. 
potasxii arsen it ts, 164. 
citratis, 72. 
impurities in, 647. 
soclce, 81. 
impurities in, 647. 
volumetric estima- 
tion of, 560. 
chloratce, 86. 
effervescent, 85. 
sodii arseniatis, 166. 
silicatis, 352. 
Liquor, sndii silicatis, impurities 
in, 647. 
strychnince,, 390. 
zinci chloridi, 130. 
impurities in, 647. 
Liquorice, 414, 420. 
sugar, 414. 
List of apparatus, xi. 
chemicals, xiii. 
reagents, xiii. 
Litharge, 206. 
Lithates, 358. 
Lithii benzoas, 223. 
impurities in, 648. 
bromidum, 223. 
impurities in, 648. 
carbonas, 223. 
impurities in, 648. 
citras, 223. 
impurities in, 648. 
salicylas, 223. 
impurities in, 648. 
Lithic acid, 358. 
Lithium, 223. 
analytical reactions of, 224. 
benzoate, 223. 
bromide, 223. 
carbonate, 223. 
citrate, 223. 
derivation of word, 33. 
flame, 224. 
fluoride, 223. 
salicylate, 223. 
silicate, 223. 
sulphate, 223. 
urate, 224. 
Litmus, 94, 486. 
-paper, 94. 
solution of, 94. 
Litre, relation of, to pints, 532. 
Liver of sulphur, 67. 
Lixiviation, 86. 
Loadstone or Lodestone, 138. 
Loaf-sugar, 411. 
Lobelia, 397. 
vinegar, 295. 
Lobelina. 397. 
Lobeline, 397. 
Logwood. 29, 486. 
solution of, bleached by chlo- 
rine, 29. 
Long pepper, 397. 
Looking-glasses, 238. 
Lotio hydragyri nigra, 200. Louisa-blue, 486. 
Lozenges, 517. 
Lucifers, 24. 
Lugol’s solution, 271. 
Lunar caustic, 214. 
Lupulin, 481. 
oleo-resin of, 481. 
Lupuline, 397. 
Lupulinic acid, 481. 
Lupulinum, 481. 
impurities in, 648. 
Lupulns, 401, 481. 
Luteolin, 484. 
Luting, 96. 
fire-clay, 197. 
linseed-meal, 96. 
Lycopodium, 486. 
impurities in, 648. 
Mack, 465. 
fixed oil of, 465. 
volatile oil of, 473. 
Manx, 473. 
Madder, 485. 
Magenta, 487. 
Magnesia, 118. 
effervescing citrate, 118. 
impurities in, 648. 
calcined, 118. 
fluid, 117. 
hydrous carbonate, 116. 
lev is, 116. 
ponder osa, 118. 
Magnesian limestone, 115. 
Magnexii carbonus, 116. 
impurities in, 648. 
lev is, 116. 
carbonatis, liquor, 117. 
citrus qranulatus, 118. 
impurities in, 648. 
sulphas, 115. 
impurities in, 648. 
sulphis, 303. 
impurities in, 648. 
Magnesite, 115. 
Magnesium, 115. 
analytical reactions of, 119. 
and ammonium arseniate, 119. 
ammonium phosphate, 
119. 
carbonate, 119. 
chloride, 115. 
citrate, 118. 
derivation of word, 32. 
INDEX. 
Magnesium, detection of, in 
presence of barium and 
calcium, 122. 
euxanthate, 484. 
for analytical purposes, 171. 
hypophosphite, 341. 
limestone, 115. 
oxide, 118. 
phosphate, in bones, 109. 
purrate, 484. 
quantitative estimation of, 589. 
separation from barium and 
calcium, 119, 122. 
silicate, 351. 
sulphate, 115, 589. 
sulphite, 303. 
Magnetic iron ore, 138. 
oxide of iron, 153. 
Magnolia, 401. 
Magpie test for mercury, 204. 
Maize-smut, 478. 
-starch (fig.), 403. 
Malachite, 187. 
Malaguti’s law, 376. 
Malate of atropine, 392. 
nicotine, 397. 
Malates, 345. 
Male fern oil, 467. 
Malic acid, 345. 
Mallow tea, 407. 
Malt, 406. 
extract of, 406. 
substitute, 411. 
Maltose, 411, 030. 
Mai turn, 406. 
Manganate of potassium, 76, 227. 
Manganese, 228. 
analytical reactions of, 228. 
black oxide of, 228. 
Crum’s test for, 230. 
derivation of word, 33. 
quantitative analysis of black 
oxide of, 590. 
sulphate, 229. 
impurities in, 648. 
Mangani oxidum nigrum, 228. 
sulphas, 229. 
Manganous chloride, 228. 
hydrate, 229. 
sulphide, 229. 
Mangosteen oil, 466. 
Manihot starch (fig.), 403. 
Manna, 415. 
impurities in, 648. 700 
INDEX 
Mannite, 415. 
Mannitic fermentation, 426. 
Manufacturing chemists, 14. 
Manures, analysis of, 635. 
Maranta starch (tig.), 403. 
Maraschino, 427. 
Marble, 103. 
Margarine, 465. 
Margosa-bark, 400. 
Marigold, 400. 
Marine soap, 466. 
Mariotte’s law, 52. 
Marjoram, 473. 
Marking-ink, 214. 
Marl, 135. 
Marrubein, 401. 
Marrubium, 401. 
Marseilles soap, 464. 
Marsh-gas, 438. 
Marshmallow, 407. 
Marsh’s test for arsenicum, 169. 
Massa Jerri carbonatis, 142. 
copaiba’, 480. 
hydrargyri, 191. 
Massicot, 206. 
Mastic, 479. 
Mastiche, 479. 
Mastichic acid, 479. 
Masticin, 479. 
Mate, 398. 
Maticce folia, 401. 
Matico, 400. 
Matricaria chamomilla, 471. 
Mauve, 487. 
May-apple, 479. 
Meadow-sweet, oil of, 446. 
Measurement of temperature, 522. 
Measures, 529 et seq. 
Mechanical and chemical combi- 
nation, difference between, 
30, 35. 
medicines, 238. 
Meconate of morphine, 385. 
Meconic acid, 346, 493. 
Meconidine, 380. 
Meconine, 380. 
Meconoisine, 380. 
Meerschaum, 351. 
Mel, 414. 
impurities in, 648. 
despumatum, 414. 
Melam, 353. 
Melasses, 414. 
Melegueta pepper, 473. 
Melia azedarach, 401. 
Melissa, 473. 
Melissic acid, 468. 
Melting-points, Table of, 526. 
of fats, etc., to determine, 526. 
of metals, 527. 
Melissyl, palmitate of, 465. 
Melon-essence, 446. 
Memoranda, analytical, 256, 361. 
Menispermum canadense, 393. 
Mentha, 473. 
Menlhce piper ike, 473. 
viridis, 473. 
Menthene, 473. 
Menthol, 473. 
Mercuric ammonium, chloride of, 
191, 202. 
chloride, 197, 201. 
cyanide, 276. 
hexiodide, 270. 
iodide, 193, 201. 
oxide, 199. 
oxynitrates, 196. 
oxysulphate, 197. 
nitrate, 195. 
salts, 192. 
analytical reactions of, 
204, 494. 
sulphate, 196. 
snip hide, 203. 
Mercurius vitae, 177. 
Mercurous ammonium, chloride 
of, 202. 
chloride, 197, 201. 
chromate, 205. 
iodide, 193. 
nitrate, 195. 
oxide, 200. 
salts, 192. 
analytical reactions of, 
203. 
sulphate, 196. 
sulphide, 203. 
Mercury, 191. 
amido-ehloride, 202. 
ammoniated, 202. 
ammonio-chloride, 202. 
analytical reactions of, 205. 
antidotes to, 205. 
basic sulphate, 197. 
black oxide, 200. 
carbonates, 205. 
cyanide, 276. 
chlorides, 201. INDEX 
701 
Mercury, derivation of word, 32. 
hex iodide, 270. 
iodides, 193, 201. 
galvanic test for, 204. 
magpie test for, 204. 
native sulphide, 191. 
nitrates, 195. 
nomenclature of salts of, 191. 
of life, 177. 
in organic mixtures, detection 
of, 494. 
oxides, 201. 
oxynitrates, 196. 
oxvsulphate, 197. 
oxysulphide, 203. 
quantitative estimation of, 595. 
subchloride, 198. 
sulphates, 196. 
sulphide, 191, 203. 
yellow oxide, 200. 
Meta-, meaning of, 239. 
Metaboracic acid, 330. 
Metachloral, 444. 
Metacinnamein, 482. 
Metadihvdroxylbenzol, 450. 
Metallic elements, 15. 
Metalloids, 15. 
Metals, 15. 
of minor pharmaceutical im- 
portance, 222. 
quantitative estimation of, 581. 
Table of the fusibility of, 
527. 
Metamerides, 408. 
Metamerism, 408. 
Metantimonic acid, 178. 
Metaphosphates, 346. 
Metaphosphoric acid, 346. 
Metastannates, 239. 
Metastannic acid, 239. 
Metastyrol, 483. 
Metathesis, 77, 289. 
Metavanadates, 330. 
Methyl, 438. 
conia, 395. 
hydride, 438. 
-orange, 566. 
-protocatechuic aldehyd, 360. 
salicylate, 446. 
Methylamine, 378. 
51 ethylated spirit, 439. 
sweet spirit of nitre, 440. 
Methylene, dichloride of, 442. 
Methylie alcohol, 439. 
Methylie alcohol, detected in pres- 
ence of ethylic alcohol, 439. 
Metre, 531. 
relation of, to inches, 531, 533. 
Metric system, 530 et seq. 
of weights and measures, 
its relation to the Eng- 
lish or United States, 
531 et seq. 
weights and measures of, 
530 et seq. 
Meum, 482. 
Mezereon, 479. 
Mezereum, 479. 
Mica, 135. 
partis, 412. 
Microcosmic salt, 369. 
Microscopic examinations of uri- 
nary sediments, 508. 
Microscopy of starches, 403. 
Microspectroscope, 492. 
Mindererus’s spirit, 91. 
Milk, 457. 
-sugar, 412. 
-sulphur, 298. 
Mimotannic acid, 355. 
Mineral acids, detection of, in or- 
ganic mixtures, 495. 
chameleon, 228. 
kermes, 179. 
Kilbride, 149. 
purple, 486. 
rouge, 486. 
Minerals, general analysis of, 367 
et seq. 
special analysis of, 367. 
Minim, 538. 
Minium, 206. 
Mint, 473. 
Mir bane, essence of, 448. 
Mistura ferri aromatica, 158. 
composita, 142. 
potassii citratis, 322. 
M ixture, definition of, 57. 
different from chemical com- 
bination, 30. 
Mixtures, 517. 
Mohr’s burette, 555. 
Moist sugar, 411. 
Molasses, 414. 
Molecular volume, 55. 
weight, 54, 261, 549. 
weights, definition of, 58. 
Molecule, definition of, 57. 702 
INDEX 
Molecules, 41, 57. 
Molybdate of ammonium, 329. 
sodium, 329. 
Molybdenum, 660. 
sulphide, 329. 
Molybdic acid, 501. 
Monads, 121. 
Monamines, 378. 
Mnnnrda, 475. 
Monobasic acids, 260. 
Monobasylous radicals, 260. 
Monobrom-camphor, 476. 
Mononitrocellulin, 4 )9. 
Monsel’s solution, 147. 
Mordants, 137. 
Mori succus, 485. 
Morphina, 380. 
impurities in, 648. 
Morpliince acetas, 380. 
hydrochloras, 381. 
sulphas, 381. 
Morphine or Morphia, 380. 
acetate, 380. 
analytical reactions of, 381, 
498. 
hydrochlorate, 381. 
in organic mixtures, detection 
of, 497. 
quantitative estimation of, 627. 
Mosaic gold, 240. 
Mosandrum, 660. 
Moschus, 459. 
moschiferus, 459. 
Mother-liquor, 107. 
Motion from heat, 84. 
Mottled soap, 464. 
Mountain-blue, 487. 
-limestone, 115. 
Mucic acid, 415. 
Mucilage of bael, 407. 
gum-acacia, 112. 
linseed, 407. 
marshmallow, 407. 
quince, 407. 
slippery elm, 407. 
starch, 404. 
squill, 407, 424. 
tragaeanth, 112. 
Mucilayo acacice, 112. 
amyli, 404. 
tragacanthce, 112. 
Mucuna puriens, 238. 
Mulberry calculus, 516. 
-essence, 446. 
Mulberry-juice, 485. 
-sugar, 411. 
Mulder’s process for estimating 
alcohol, 032. 
Multiple proportions, law of, 48, 
194, 286. 
Murexid, 358. 
Musk, 459. 
deer, 459. 
Mustard, 453. 
artificial oil of, 453. 
essential oil of, 453. 
fixed oil of, 467. 
“plaster,” 453. 
Mylabris cichorii, 477. 
Myrcia acris, 427. 
Mvristate of glyceryl, 465. 
My ristic acid, 468, 473. 
Myristica, 473. 
My risticene, 473. 
Mvristicol, 473. 
Myristin, 465. 
Myronate of potassium, 453. 
Myrosin, 453. 
Myroxylon Pereiras, 482. 
Toluifera, 482. 
Myrrh, 482. 
Myrrha, 482. 
Myrrhic acid, 482. 
Myrtus communis, 473. 
Naphthalic acid, 333. 
Naphthalin, 333. 
Narceia, 380. 
Narcotine, 380. 
Natal aloes, 452. 
Nataloin, 452. 
Natrium, 32. 
Natural philosophy, 42. 
Nedandra Rod ice i, 393. 
Nectandria, 397. 
Nectandrice cortex, 393. 
Needle iron ore, 149. 
Negative radicals, 448. 
Neptunium, 660. 
Neroli oil, 471. 
Nessler test, 558. 
Neutral chromate, 102. 
Neutralization, 94. 
Nickel, 232. 
analytical reactions of, 232. 
arsenio-sulphide, 232. 
cobalt! cyanide, 232. 
cyanide, 232. INDEX. 
703 
Nickel, derivation of word, 34. 
hydrate, 232. 
separation of, from cobalt, 233. 
sulphide, 232. 
Nickar nuts, 400. 
Nicotia, nicotine, nicotina, or nico- 
tylia, 397. 
Nicotiann tabacum, 397. 
Nieshnic bitters, 393. 
Nihilum album, 132. 
Nim, 400. 
Niobium, 661. 
Nitrate of ammonium, 92. 
argent - amnion * ammonium, 
203. 
barium, 102. 
bismuth, 247. 
cadmium, 246. 
iron, 154. 
lead, 208. 
mercury, 195. 
potassium, 60, 284. 
silver, 213. 
standard solution of, 567. 
sodium, 81, 282. 
strontium, 225. 
Nitrates, 284. 
analytical reactions of, 285. 
quantitative estimation of, 601. 
Nitre, 284. 
cubic, 284. 
sweet spirit of, 348, 434. 
Nitric acid, 286. 
antidotes to, 288. 
in organic mixtures, de- 
tection of, 495. 
volumetric estimation of, 
565. 
anhydride, 286, 287. 
oxide, preparation of, 286. 
peroxide, 286. 
Nitrite of amyl, 446. 
ethyl, 348. 
potassium, 348. 
Nitrites, 348. 
analytical reactions of, 347. 
Nitrobenzol, 450. 
in oil of bitter almonds, test 
for, 417. 
Nitrocellulin, 409. 
Nitrogen, 25. 
derivation of word, 31. 
in the atmosphere, 26. 
oxides, 286. 
Nitrogen, peroxide, 286. 
preparation of, 25. 
properties of, 26. 
quantitative estimation of, in 
organic compounds, 615 et 
seq. 
relative weight of, 26. 
Nitrohvdrochlorie acid, 183, 285. 
Nitromuriatic acid, 285. 
Nitrous acid, 286. 
anhydride, 286. 
ether, 347. 
oxide, 286. 
Nomenclature of salts:—■ 
alkaloids, 378. 
anhydrides, 84. 
anhydrous bodies, 84. 
-ate, 73. 
bi-, 72. 
carbonization, evaporation, ig- 
nition, incineration, 100. 
double salts, 78. 
hydrates, 65. 
hydrous bodies, 84. 
hyper-, 145. 
-ic, -ous, 72, 75, 140. 
-icle, -ite, 75, 140. 
iron salts, 140. 
mercury compounds, 192. 
per-, 145. 
Non-drying oils, 466. 
Non-metallic elements, 15. 
Non-metals, 15. 
Nordhausen sulphuric acid, 307. 
Norwegium, 661. 
Notation, 41 et seq. 
Notes, analytical, 256, 361. 
Nutmeg, expressed oil, 473. 
oil of, 473. 
Nutrition, plastic elements of, 459. 
Nux vomica, 388. 
Oak-bark, 354. 
black, 484. 
Oatmeal, 402. 
Occlusion, 244, 245. 
Ochre, 484. 
Octahedral, 169. 
(Enanthvlic acid, 468. 
Official liquids, specific gravity of, 
543. 
substances, volumetric estima- 
tion of, 554, 556, 563, 566, 
572, 575. 704 
INDEX, 
Official formula, 28. 
Officinal formula, 28. 
Oil, ajowan, 471. 
ajwain, 471. 
allspice, 472. 
almond, 466. 
amber, 352. 
aniseed, 471. 
arachis, 467. 
apple, 446. 
bay, 473. 
benne, 467. 
bergamot, 471. 
bitter almond, 416. 
artificial, 448. 
boldo, 472. 
buchu, 472. 
cacao, 465. 
cajuput, 472. 
cake, 466. 
camphor, 476. 
cannabis indica, 478. 
capsicum, 394. 
caraway, 472. 
cardamoms, 472. 
cascarilla, 472. 
cassia, 472. 
castor, 467. 
cedra, 471. 
chamomile, 471. 
chenopodium, 475. 
cinnamon, 472. 
citron, 471. 
citronella, 472. 
cloves, 472. 
cocoa-nut, 465. 
cod-liver, 466. 
copaiva, 472. 
coriander, 472. 
cotton-seed, 466. 
croton, 466. 
cubeb, 472. 
cummin, 472. 
dill, 471. 
earth-nut, 467. 
eggs, 456. 
elder-flower, 474. 
ethereal, 453. 
eucalyptus, 473. 
fennel, 473. 
garcinia, 466. 
garlic, 453. 
geranium, 473. 
gingelly, 467. 
Oil, ginger, 475. 
ginger grass, 473. 
grains of paradise, 473. 
ground-nut, 467. 
hop, 481. 
horseinint, 474. 
horseradish, 452, 471. 
Indian hemp, 478. 
jaborandi, 397, 
juniper, 473. 
lard, 464. 
lavender, 473. 
lemon, 470. 
lemon-grass, 475. 
lime, 470. 
linseed, 466. 
lycopodium, 466. 
mace, fixed, 465. 
volatile, 473. 
male-fern, 467. 
mangosteen, 466. 
meadow-sweet, 446. 
melissa, 475. 
mustard, artificial, 453. 
fixed, 467. 
volatile, 474. 
mvrcia, 473. 
myrtle, 473. 
neroli, 470. 
nutmeg, 473. 
fixed, 465. 
volatile, 473. 
olibanum, 482. 
olive, 467. 
omum, 471. 
orange-flower, 471. 
-rind, 471. 
origanum, 473. 
orris, 473. 
pennyroyal, 473. 
pepper, 397. 
peppermint, 473. 
petit grain, 471. 
pilocarpine, 397. 
pimento, 472. 
ptvchotis, 471. 
rose, 473. 
rosemary, 474. 
rue, 474. 
saffron, 485. 
sandal-wood, 474. 
santal, 474. 
sassafras, 474. 
savine, 474. INDEX. 
705 
Oil, sesame, 467. 
shark liver, 467. 
spearmint, 473. 
sperm, 465. 
star-anise, 471. 
sweet-flag, 474. 
tar, 481. 
teel, 467. 
theobroma, 465. 
thyme, 475. 
turmeric, 475. 
turpentine, 475. 
valerian, 475. 
verbena, 475. 
vitriol, 307. 
water-hemlock, 472. 
wine, 453. 
winter-green, 446. 
wormseed, 475. 
Oils and fats, composition of, 462. 
Oils, analysis of, 635. 
drying, 466. 
essential, 469. 
tested for alcohol, 47 0. 
fixed, 466. 
non-drying, 468. 
volatile, 469. 
process for, 489. 
Ointments, 517. 
Okra, 407. 
(Men destillala, impurities in, 649. 
Oleate of glyceryl, 462. 
of lead, 209. 
Oleates, 463. 
Oleatnm hydrargyri, 463. 
veratrince, 463. 
Olefiant gas, 453. 
Oleic acid, 462. 
Oleine, 462. 
Oleo-resins, 479. 
Oleoresinci aspidii, 466, 481. 
capsid, 481. 
cubebce, 481. 
lupulini, 481. 
pi per is, 481. 
zingiberis, 481. 
Oleum adipis, 464. 
asthereum, 453. 
impurities in, 649. 
amygdalae amarce, 416. 
ditlcis, 466. 
expression, 466. 
andropogi eitratis, 475. 
impurities in,. 649. 
Oleum anethi, 471. 
anisi, 471. 
anthemidis, 471. 
arachis, 467. 
aurantii corticis, 471. 
florum, 471. 
bergamii, 471. 
cajuputi, 472. 
earui, 472. 
caryophylli, 472. 
chenopodii, 475. 
einnamomi, 472. 
copaibce, 472. 
coriandri, 472. 
crotonis, 466. 
cubebce, 472. 
erigerontis, 473. 
eucalypti, 473. 
fceniculi, 473. 
gaultherias, 446. 
impurities in, 649. 
gossypii sent in is, 466. 
hedeomce, 473. 
juniperi, 473. 
lavandulce, 473. 
Jlorum, 473. 
impurities in, 649. 
limonis, 470. 
lini, 466. 
macis, 465, 473. 
rnenthce piperita473. 
viridis, 473. 
morrhuce, 466. 
myrcice, 473 
myristicce, 473. 
expressum, 465. 
myrti, 473. 
olivus, 467. 
impurities in, 649. 
phosphoratum, 325. 
picis liquidce, 474. 
pimento?, 472. 
pulegii, 473. 
ricini, 467. 
rosce, 473. 
rosmarini, 474. 
rutce, 474. 
sabince, 474. 
santali, 474. 
sassafras, 474. 
sesami, 467. 
sinapis volatile, 474. 
impurities in, 649. 
terebinlhince, 475. 706 
INDEX 
Oleum ilieobromce, 465. 
impurities in, 649. 
thymi, 475. 
tiglii, 466. 
Valerianae, 475. 
Olibanum, 482 
Olive-oil, 467. 
Omentum, 464. 
Omum oil, 482. 
Opal, 351. 
Ophelia, chirata, 348. 
Ophelic acid, ,348. 
Opianic acid, 380. 
Opianine, 380. 
Opii pulvis, 37 9. 
Opium, 379. 
detection of, in organic mix- 
tures, 497. 
denarcotimtum, 379. 
estimation of morphine in. 
627. 
impurities in, 649. 
vinegar. 295. 
Orange-chrome, 210. 
-flower, 471. 
oil, 471. 
-rind oil, 471. 
Orchil, 486. 
Orcin, 486. 
Orchis tuber, 407. 
Ordeal-poison, 397. 
Orel 1 in, 485. 
Organic analysis, 611. 
bases, 377. 
chemistry, 376. 
compounds, 376. 
Origanum, 473. 
Orpiment, 484. 
Orris, butter of, 473. 
oil of, 473. 
Ortho-, meaning of, 347. 
Ortho-dihydroxylbenzol, 450. 
Orthophosphates, 347. 
Orthophosplioric acid, 347. 
Orthovanadates, 330. 
Oryza, starch of (fig.), 403. 
saliva, 402. 
Os upturn, 109. 
Osmium, 245, 661. 
Otto of rose, 473. 
Ounce, 529. 
Ourari, 390. 
-our, meaning of, 75, 140. 
Ovum, 456. 
Ox-bile, 464. 
-gall. 4(54. 
Oxalate of ammonium, 94. 
barium, 313. 
calcium, 313. 
cerium, 226. 
iron, 313. 
potassium, 313. 
silver, 313. 
sodium, 313. 
strontium, 225. 
Oxalates, 313. 
analytical reactions of, 313, 
496. 
from phosphates and ferric 
oxide, separation of, 371. 
quantitative estimation of, 
607. 
Oxalic acid, 313. 
antidotes, 314. 
chemically pure, 313. 
in organic mixtures, de- 
tection of, 495. 
standard solution of, 556. 
Oxide of aluminium, 137. 
antimony, 178. 
bismuth, 249. 
calcium, 105. 
chromium, 234. 
copper, 188. 
iron, black, 153. 
lead, 206. 
magnesium, 118. 
manganese, 228. 
mercury, 199. 
silicon, 351. 
silver, 214. 
tin, 239. 
zinc, 132. 
Hubbuck’s, 132. 
Oxides identified, 373. 
Oxides of nitrogen, 286. 
Oxidizing flame, 369. 
Oxyacetate of copper, 188. 
of lead, 208. 
Oxyacid salts, 284. 
Oxyacids of sulphur, 343. 
Oxycarbonate of bismuth, 249. 
Oxychloride of antimony, 177. 
Oxyehromate of lead, 210. 
Oxygen, 16. 
derivation of word, 31. 
from ozone and antozone, 272. 
in the air, 16, 26. INDEX 
707 
Oxygen, its relation to animal 
and vegetable life, 19. 
preparation of, 16. 
properties of, 20. 
quantitative estimation of, in 
organic compounds, 611 el 
seq. 
solubility in writer, 19. 
specific gravity of, 24. 
weight of 100 cubic inches, 
549. 
Oxygenated water, 102. 
Oxyhvdrates of iron, 148. 
Oxyiodate of iron, 293. 
Oxymel, 414. 
of squill, 414. 
Oxynitrates of mercury, 196. 
bismuth, 248, 249. 
Oxysalts, 284. 
Oxysulphate of iron, 141. 
mercury, 197. 
Oxysulphide of antimony, 179. 
mercury, 203. 
Ozokerite, 465. 
Ozone, 272, 512. 
Palas tree, 355. 
Palladium, 245, 631. 
Palm-oil, 465. 
Palmitate of cetyl, 465. 
glyceryl, 465. 
melissyl, 465. 
Palmitic acid, 468. 
Palmitin, 465. 
Pancreatin, 461. 
Pansy, 551. 
Papaine, 461. 
Papaver r/iceas, 485. 
somniferum, 379. 
Papaverine, 380. 
Pupaveris capsulce, 379. 
Paper, bibulous, 106. 
for filtering, 106, 582. 
Papers, test-, 94. 
Para-, meaning of, 317. 
Paracvanogen, 278. 
Paradihydroxylbenzol, 450. 
Paraguay tea, 398. 
Parallin, 424. 
Paratartaric acid, 317. 
Pareira, 393. 
Paricine, 393. 
Parietinic acid, 335. 
P:iriDPnin 424. 
Pari 11a, 393. 
Paris blue, 486. 
red, 486. 
Particles, elementary, 46. 
Pauli inia sorb Hits, 398. 
Paul’s method for estimating the 
purity of sulphate of qui- 
nine, 624. 
Patent sugar, 413. 
Pear wine, 529. 
Pearlash, 61. 
Pearl-barley, 402. 
-sago starch (fig.), 403. 
-white, 248, 487. 
Peas, 459. 
Pectin, 407. 
Pelargonic acid, 468. 
Pelletierine, 355. 
Pellitory-root, 479. 
Pelosia, 393. 
Pelosine, 393. 
Pentachloride of antimony, 177. 
Pentathionic acid, 313. 
Pepo, 401. 
Pepper, black, 397. 
cayenne, 394. 
cubeb, 397. 
long, 397. 
oil of, 397. 
resin of, 481. 
white, 397. 
Peppermint oil, 473. 
Pepsin, 460. 
Pepsinum Saccharalum, 461. 
impurities in, 649. 
Peptone, 461. 
Per-, meaning of, 145. 
Perbromates, 268. 
Percha tree, 483. 
Perchlorate of potassium, 291. 
Perchloric acid, 291. 
Perchloride of gold, 242. 
iron, 144. 
platinum, 243. 
tin, 239. 
Perfumes, 470. 
Perhydrate of iron, 148. 
Periodide of ammonium, 270. 
mercury, 270.' 
potassium, 270. 
Permanganate of potassium, 76, 
227. 
its use in volumetric an- 
alysis, 572. 708 
INDEX. 
Pernitrate of iron, 154. 
Peroxide of barium, 102. 
hydrogen, 102. 
iron, 149. 
hydrated, 148. 
lead, 208. 
nitrogen, 286. 
Peroxyhydrate of iron, 148. 
Persian berries, 484. 
Personne’s solution, 571. 
Persulphate of iron, 146. 
Persulphide of hydrogen, 299. 
Peru, balsam of, 482. 
Pervuine, 482. 
Petal ite, 223. 
Petit’s method for estimation of 
morphine in opium, 628. 
Petrolatum, 448. 
impurities in, 649. 
Petroleum benzin, 448. 
etber, 448. 
ointment, 448. 
Pettenkofer’s test for presence of 
bile, 464. 
Peumus boldus, 472. 
Pewter, 176, 206, 238. 
Phaeoretine, 335. 
Pharaoh’s serpents, 353. 
Pharbitisin, 422. 
Pharbitis nil, 422. 
Pharmaceutical chemists, 14. 
Society of Great Britain, ex- 
aminations of, 14. 
Pharmacists, 14. 
Pharmacy, 14. 
Plienic acid, 449. 
alcohol, 449. 
Phenol, 449. 
Phenolthalein, 566. 
Phenyl, 449. 
Philippium, 661. 
Phosphata of ammonium, 93. 
barium, 329. 
calcium, 103, 109, 329. 
iron, 142, 329. 
magnesium and ammonium, 
119. 
and ammonium from 
oxalates and ferric 
oxide, separation of, 
371. 
in bones, 109. 
silver, 215. 
sodium, 110. 
Phosphate of sodium, how pre- 
pared from phosphate of 
calcium, 110. 
Phosphates, 324. 
analytical reactions of, 323. 
quantitative estimation of, 003. 
Phosphide of zinc, 325. 
Phosphites, 348. 
test for, 349. 
Phosphomolybdic acid, 501. 
Phosphoretted hydrogen, 341. 
oil, 325. 
Phosphoric acid, 25, 326, 348. 
diluted, 320. 
quantitative estimation of 
free, 608. 
anhydride, 24, 348. 
Phosphorous acid, 348. 
Phosphorus, 24, 324. 
combustion of, 24. 
derivation of word, 31. 
detection of, in organic mix- 
tures, 497. 
granulated, 325. 
impurities in, 049. 
pill, 325. 
properties of, 24. 
red or amorphous, 327. 
trihydride, 341. 
Phthalic acid, 333. 
Phyllocyanin, 486. 
Phylloxanthin, 486. 
Physical isomerides, 407. 
Physics, 43. 
Physostigma, 397. 
Physostigmia, 397. 
Physostigmine, 397. 
salicylate, 397. 
impurities in, 649. 
Phylollacca, 401. 
Phytolaccin, 401. 
Picric acid, 450. 
Picrotin, 422. 
Picrotoxinum, 422. 
impurities in, 649. 
Pigments, 484. 
Pigmentum nigrum, 487. 
Pills, 517. 
Pilocarpine, 397. 
Pilocarpine hydrochloras, 397. 
impurities in, 649. 
Pilocarpus, 397. 
Pilule aloes et fern', 141. 
catharticce composites, 199. INDEX. 
709 
Pilulce antimonii composite, 199. 
Jerri compositce, 142. 
iodidi, 31. 
phosphori, 325. 
plnmbi cum opio, 207. 
Pimaric acid, 478. 
Pimento, 472. 
Pimento, 472. 
oil, 472. 
Pimpinella anisum, 471. 
Pineapple, essence of, 446. 
Pinic acid, 478. 
Pinipicrin, 474. 
Pink saucers, 486. 
the common, 424. 
Pink root, 398. 
Pins, 238. 
Pint, 538. 
Pinas, 475, 478. 
Piper nigrum, 397. 
Piperia, 397. 
Piperic acid, 398. 
Piperidia, 398. 
Piperidine, 398. 
Piperina, 397. 
impurities in, 649. 
Piperin, 397. 
Pipsissewa, 417. 
Pistachia terebinthus, 474. 
Pitch, 481. 
Burgundy, 479. 
Pituri, 397. 
Pix burgundica, 479. 
canadensis, 481. 
liquida, 481. 
Plantago ispaghula, 407. 
Plants and animals, complemen- 
tary action on air, 19. 
Plaster of arnmoniacum and mer- 
cury, 191. 
mercurv, 191. 
Paris, 103, 487. 
Plasters, 209, 517. 
Plastic elements of nutrition, 
459. 
Platinic salts, 244. 
Platinous salts, 244. 
Platinum, 243. 
analytical reactions of, 244. 
and ammonium chloride, 97, 
586. 
and potassium chloride, 77. 
black, 244. 
derivation of word, 34. 
Platinum foil, 76, 243. 
perchloride, 244. 
residues, to recover, 245. 
spongy, 245. 
sulphide, 244. 
Pleurisy-root, 400. 
Plumbago, 30. 
Plumbi acetas, 207. 
impurities in, 649. 
carbonas, 207. 
impurities in, 649. 
emplastrum, 209. 
iodidum, 209. 
impurities in, 650. 
nitras, 208. 
impurities in, 650. 
ox id am, 206. 
impurities in, 650. 
subacetatis, liquor, 208. 
“Plummer’s pills,” 199. 
Plumbic peroxide, 208. 
acetate, sulphate, etc. (vide 
Salts of Lead). 
Plumbum, 33. 
Pocula emetica, 176. 
Podophyllum, 479. 
Poison-ivy, 357. 
-oak, 357. 
Poisonous alkaloids 497, 500. 
Poisons, antidotes to (vide Anti- 
dotes, detection of, in or- 
ganic mixtures, 493 et seq.). 
Polybasic acids, 261. 
Polybasvlous radicals, 261. 
Polychroite, 485. 
Polygala senega, 424. 
Polygalic acid, 424. 
Polymerism, 408. 
Polymorphism, 409. 
Polymorphous bodies, 409. 
Polysulphide of calcium, 300. 
Pomegranate rind, 355. 
Pomegranate-root bark, 355. 
Porcelain, 351. 
Port wine, 427. 
Porter, 427. 
Portland cement, 351. 
Positive radicals, 449. 
Potash alum, 135. 
solution of caustic, 67. 
to prepare pure, 67. 
sulphurated, 67. 
volumetric estimation of solu- 
tion of, 560. 710 
INDEX. 
Potash-water, 67. 
Potashes, 61. 
Polassa, 67. 
impurities in, 650. 
cum calce, 67. 
impurities in, 650. 
sulphurata, 67. 
impurities in, 650. 
Potasses (vide Potassii). 
effervescens, liquor, 71. 
liquor, 61, 67. 
to prepare pure, 67. 
prussias flam, 276, 337. 
Potassic hydrate, etc. (vide Salts 
of Potassium). 
Potassii acetas, 68. 
impurities in, 650. 
volumetric estimation of, 
562. 
bicarbonas, 70. 
impurities in, 650. 
bichrornas, 234. 
impurities in, 650. 
bitart ras, 61, 73, 79, 315. 
impurities in, 650. 
bromidum, 75, 569. 
impurities in, 650. 
carbonas, 61. 
pura, 61. 
impurities in, 651. 
chloras, 290. 
impurities in, 651. 
citras, 72. 
impurities in, 651. 
cyanidum, 276. 
impurities in, 651. 
et sodii tartras, 73, 85. 
impurities in, 651. 
ferrocyanidum, 276. 
impurities in, 651. 
hypophosphis, 341. 
impurities in, 651. 
iodidum, 73. 
impurities in, 651. 
nitras, 72, 284, 603. 
impurities in, 651. 
permanganas, 76, 227. 
impurities in, 651. 
volumetric estimation of, 
562. 
sulphas, 72, 284. 
impurities in, 651. 
sidphis, 303. 
impurities in, 651. 
Potassii sulphis, volumetric estima- 
tion of, 574. 
tarfras, 73. 
impurities in, 652. 
Potassio-citrate of iron, 152. 
-cupric tartrate, 630. 
-tartrate of antimony, 178, 316. 
-tartrate of iron, 152. 
Potassium, 60. 
acetate, 68. 
acid carbonate, (vide Bicarbo- 
nate). 
tartrate, 79. 
analytical reactions of, 77. 
antimoniate, 87. 
bicarbonate, 70, 560. 
chemically pure, 561. 
bichromate, 234. 
bitartrate, 79, 315. 
borotartrate, 331. 
bromate, 75. 
bromide, 75. 
carbonate, 61, 560. 
chemically pure, 561. 
carbonates, volumetric analy- 
sis of, 560. 
chlorate, 16, 290. 
chloride, 77. 
chromate, 102. 
and platinum, chloride, 77. 
citrate, 72. 
cobalticyanide, 231. 
cyanate, 335. 
cyanide, 276. 
derivation of word, 31. 
ferrate, 140. 
ferridcyanide, 339. 
ferrocyanide, 276, 339. 
flame test, 79. 
hydrate, 61. 
to prepare pure solution, 
hypophosphite, 341. 
iodate, 75, 293. 
iodide, 73, 571. 
manganate, 76, 227. 
myronate, 453. 
nitrate, 60, 72, 284, 603. 
oleate, 456. 
perchlorate, 291. 
periodide, 270. 
permanganate, 76,227,562,572. 
preparation of, 61. 
properties of, 61. 711 
Potassium, quantitative estima- 
tion of, 560, 562. 
quanti valence of, 61. 
red chromate, 102, 236. 
prussiate, 339. 
salts, analogy of, to sodium 
salts, 87. 
sodium and ammonium, sep- 
aration of, 99. 
sodium tartrate, 85. 
sources of, 60. 
sulphate, 72, 281. 
sulphides, 67. 
sulphite, 574. 
sulphocyauate, 353. 
sulphurated, 67. 
tartrate, 72. 
acid, 61, 78, 316. 
tri-iodide, 270. 
yellow chromate, 102. 
prussiate, 276, 337. 
Potato, 398. 
oil, 445. 
starch (fig.), 403. 
Poultices, 517. 
Pound, 538. 
Powder, bleaching-, 111. 
Powders, 517. 
soda-, 86. 
specific gravity of, 545. 
Practical analysis, 9i. 
Precipitant, 77. 
Precipitate, 77. 
Precipitated chalk, 106. 
sulphur, 300. 
Precipitates, soluble, in solutions 
of salts, 279. 
to wash, 107, 108, 583. 
to weigh, 582, 583, 587. 
Precipitation, 77. 
Preparations of the British Phar- 
macopoeia, chemical, 519. 
galenical, 517. 
Prepared carbonate of calcium, 108. 
chalk, 108. 
lard, 464. 
suet, 464. 
Pressure, correction of volume of 
gas for, 548. 
-gauges, 522. 
Prickly ash, 393. 
Principles of Chemical Philos- 
ophy, 36 (vide also Laws). 
Prims, 356. 
INDEX, 
Printer’s ink, 437. 
Prismatic nitre, 282. 
Prollius’s method for estimation 
of cinchona alkaloids, (i22. 
of morphine in opium, 628. 
Prophetin, 420. 
Proportions, atomic, 47, 194. 
constant, 47, 58. 
multiple, 48, 58. 
reciprocal, 48, 58. 
Proof spirit, 427. 
| Propionic acid, 468. 
! Propyl, 438. 
[ Propylamine, 378. 
| Propylene glycol, 453. 
Protocatechuic aldehyd, 330. 
Protopine, 380. 
Proximate analysis, 611. 
Prune, 414. 
Prunum, 414. 
Prunus serotina, 417. 
virginiana, 417. 
Prussian blue, 338, 486. 
Prussiate of potash, red, 338. 
yellow, 275, 337. 
Prussic acid, 275. 
Pseudaconitine, 392. 
Pseudojervine, 396. 
Pseudomorphine, 380. 
Pterocarpus santalinus, 485. 
Ptomaines, 502. 
Ptychotis ajowan, 471. 
Ptyalin, 513. 
Puce-colored oxide of lead, 208. 
Puddling, iron, 139. 
Pulsatilla, 332. 
Pulvis algarothi, 177. 
angelicas, 177. 
antimonmlis, 180. 
effervesces compositus, 318. 
ipecacuanh.ee et opi.i, 395. 
morphines compositus, 380. 
Pumice-stone, 351. 
Punica granatum, 355. 
Purified ox-bile, 464. 
Purple of Cassius, 243. 
foxglove, active principle in, 
418. 
Purpurine, 506. 
Purrate of magnesium, 484. 
Purree, 484. 
Pus, in urine, 512. 
Putty-powder, 239. 
Pyrethrin, 479. 712 
INDEX. 
Pyrethrum, 479. 
cavneum, 479. 
cineraria folium, 479. 
roseum, 479. 
Pyrites, copper, 187. 
iron, 139. 
Pyroarseniate of sodium, 166. 
Pyroarseniates, 166. 
Pyrogallic acid, 357. 
use of, in gas analvsis, 
357. 
Pyrogallol, 357. 
Pyroligneous acid, 294. 
Pyrolusite, 226. 
Pyrometers, 526. 
Pyromorphite, 330. 
Pyrophorus, 155. 
Pyrophosphates, 330, 349. 
Pyrophosphoric acid, 347, 349. 
Pyrovanadates, 330. 
Pyroxylic spirit, 439. 
Pyroxylin, 410. 
Pyroxylinum, 410. 
Quadrivalence, 55. 
Qualitative analysis, 99. 
Quantitative analysis, 519 et seq. 
Quantivalence, 55, 120. 
of atoms, definition of, 58. 
of acidulous radicals, 66. 
Quartz, 351. 
Quassia; lignum, 401. 
Quassin, 401. 
Quebrachine, 392. 
Quebracho-bark, 392. 
Queen’s root, 401. 
Quereitrin, 484. 
Quercitron, 484. 
Quercus alba, 354. 
cortex, 354. 
tinctoria, 484. 
Quevenne’s iron, 155. 
Quicklime, 105. 
Quillaia, 424. 
Quinamia, 388. 
Quinamine, 388. 
Quince-seeds, 406. 
Quinia, or quinine, 383. 
amorphous, 619. 
analytical reactions of, 385. 
citrate, 385. 
of iron and, 151. 
De Vrij’s process for estimat- 
ing, 616. 
Quinia, disulphate, 384. 
iodosulphate, 385. 
kinate, 383. 
quantitative estimation of, 
616. 
sulphate, 384. 
Quinicia, 388. 
Quinicine, 388. 
Quinidia, 386. 
Quin idince sulphas, 386. 
impurities in, 652. 
Quinidine, 388. 
Quinina, 383, 616. 
impurities in, 652. 
bisulphas, 384. 
impurities in, 652. 
hydrobromas, 385. 
impurities in, 652. 
kydrochloras, 385. 
impurities in, 652. 
sulphas, 384, 606. 
impurities in, 652. 
valerianas, 384. 
impurities in, 652. 
Quinine, 383. 
Quiniretin, 388. 
Quinlan’s test for presence of hile, 
464. 
Quinoidin, 388. 
Quinquivalence, 56. 
Radicals, 66. 
acidulous, 60, 259. 
formulae of, 121. 
alcohol, 448. 
basvlous, 60, 121. 
definition of, 60. 
negative, 448. 
positive, 448. 
Racemic acid, 317. 
Rai, 453. 
Raisins, 412. 
Ranunculus, 332. 
Raspberry, sugar in, 412. 
Ratafia, 427. 
Rational formulae, 428. 
Reactions, analytical, 61. 
synthetical, 61. 
Reagents, list of xv. 
Real alcohol, 428. 
Realgar, 164. 
Reaumur’s thermometer, 523. 
Reciprocal proportions, law of, INDEX. 
713 
Rectification, 126. 
Rectified oil of turpentine, 475. 
spirit, 126, 427. 
Red chromate of potassium, 234. 
coloring-matters, 485. 
corpuscles in blood, 511. 
earth, 485. 
enamel colors, 486. 
gravel, 506. 
haematite, 138. 
iodide of mercury, 193. 
litmus-paper, 94. 
lead, 208, 485. 
ochre, 485. 
oxide of iron, 150, 485. 
phosphorus, 325. 
poppy-petals, 485. 
precipitate, 199. 
prussiate of potash, 338. 
rose-petals, 485. 
sandal-wood, 485 
sanders-wood, 485. 
Venetian, 150. 
Reduced indigo, 287. 
iron, 154. 
Reinsch’s test for arsenicum, 169. 
Relations of gases, liquids, and 
solids, 42. 
Relative weight of hydrogen and 
oxygen, 24. 
Remijia bark, 388. 
Rennet, 457. 
Reseda luteola, 484. 
Resin, 478. 
arnica, 478. 
cannabis, 478. 
capsicum, 478. 
castor, 478. 
copaiba, 480. 
copal, 478. 
dragon’s blood, 478. 
ergot, 478. 
guaiacum, 421, 479. 
Indian hemp, 479. 
jalap, 422, 479. 
kamala, 479. 
kousso, 479. 
mastic, 479. 
mezereon, 479. 
pepper, 397. 
podophyllum, 479. 
pyrethrum, 479. 
rottlera, 479. 
seamrnony, 424. 
Resina, 478. 
copaibce, 480. 
j ala pop, 422. 
podophylli, 479. 
scammonii, 424. 
Resinoid substances, 478. 
Resins, 478. 
Resorcin, 450. 
Respiratory materials of food, 459. 
Retort, 125. 
Rhamni succus, 418, 486. 
Rhamnin, 484. 
Rhamnus catharticus, 486. 
frangida, 418. 
Rhapontiein, 335. 
Rhatany-root, 355. 
Rheic acid, 335. 
Rhein, 335. 
Rheum, 335. 
Rheurnin, 335. 
Rhopadin, 380. 
Rhoeados petala, 485. 
Rhodium, 245, 661. 
Rhubarb, oxalate of calcium from, 
510. 
acid in, 345. 
Rhubarbic acid, 335. 
Rhubarbarin, 335. 
Rhus cnriaria, 356. 
cotinus, 484. 
glabra, 356. 
toxicodendron, 357. 
Rice, 402. 
Rice-starch (fig.), 403. 
Ricinine, 467. 
Ricinoleate of glyceryl, 467. 
Ricinoleine, 467. 
Ringworm-powder, 335. 
Roccella, 486. 
Rochelle salt, 85, 317. 
Rock-salt, 80. 
Roll sulphur, 298. 
Roman cement, 351. 
Rosa centifolia, 473, 485. 
gallica, 485. 
Rosaniline, 487. 
Rosce canince fructus, 414. 
Roscoe’s vanadium, 329. 
Rose oil, 473. 
-petals, 473, 485. 
-water, 470. 
Rosmarinus, 474. 
Rosemary oil, 474. 
Rosin, 478. 714 
INDEX. 
Rotten-stone, 135. 
Rottlera tincloria, 479. 
Rottlerin, 479. 
Rouge, animal, 334, 486. 
mineral, 150, 486. 
vegetable, 486. 
Rubin linclonnn, 485. 
Rubidium, 661. 
liubijervine, 396. 
Rubus, 320, 356. 
ulceus, 412. 
Ruby, 135. 
Rue oil, 474. 
Rum, 427. 
Rumex, 335. 
crispus, 335. 
Rumicin, 335. 
Rust of iron, 139. 
Rotate of glyceryl, 468. 
Ruthenium, 245, 661. 
Rutic acid, 468. 
aldehyd, 474. 
Sabadillia, or sabadilline, 399. 
Sabina, 474. 
Sabince, oleum, 474. 
Saccharated carbonate of iron, 142. 
volumetric estimation of, 
577. 
pepsin, 461. 
Saccharic acid, 415. 
Saccharimetry, 630. 
Saccharine, 413. 
substances, 401, 410. 
Saccharometer, 631. 
Saccharomyces cererisice, 426. 
impurities in, 652. 
Saccharum, 412. 
impurities in, 652. 
lactis, 411. 
ustnm, 415. 
Safety-lamp, 23. 
-tube, 263. 
Safflower, 485. 
SafTranin, 484. 
Saffron, 484. 
bastard, 485. 
dyer’s, 485. 
Safren, 474. 
Safrol, 474. 
Sage, 474. 
Sago, 402. 
starch (fig.), 403. 
Sal ammoniac, 89. 
Sal prunella, 283. 
volatile, 92. 
Salep, 407. 
Salicinum, 423. 
impurities in, 652. 
Salicyl hydride, 423. 
Salicylate of lithium, 223. 
methyl, 446. 
Salicylic acid, 446, 451. 
Salieylous acid, 446. 
Saligenin, 423. 
Saliretin, 423. 
Saliva, 513. 
Salix alba, 422. 
helix, 422. 
Salseparin, 424. 
Salt, common, 80. 
definition of a, 60. 
of sorrel, 313. 
Saltpetre, 282. 
Chili, 282. 
Salts, acid, 299. 
action of the blowpipe on, 369. 
of heat on, 369. 
of sulphuric acid on, 369. 
of ammonium, volatility of, 97. 
analogies of, 87. 
analysis of insoluble, 367. 
constitution of, 60, 124, 259, 
283, 296, 375. 
formation of, 69. 
nomenclature of, 71, 75. 
of iron, nomenclature of, 140. 
physical properties of, 367. 
substitution of, for each other, 
87. 
Table of the solubility or in- 
solubility of, in water, 363. 
Salvia, 474. 
Sal viol, 474. 
Sambucene, 474. 
Sambucns, 474. 
Sand, 351. 
-bath. 28. 
-tray, 28, 198. 
Sandal-wood, oil of, 474. 
red, 474, 485. 
white, 474. 
yellow, 474. 
Sandstone, 351. 
Sanguinaria, 398. 
vinegar, 295. 
Sanguinarina, 398. 
Santalin, 485. INDEX. 
715 
Santalum album, 474. 
rubrum, 474, 485. 
Sanlonica, 423. 
Santonic acid, 423. 
Santonin, 423. 
Santoninate of sodium, 423. 
Santoninum, 423. 
impurities in, 653. 
Santoniretin, 423. 
Sapan-wood, 485. 
Sap-green, 486. 
Sapo, 463. 
animalis, 464. 
kalinus venalis, 464. 
impurities in, 653. 
mollis, 463. 
viridis, 463, 464. 
impurities in, 653. 
Saponin, 424. 
Sapphire, 135. 
Sarcince ventrindi, in urine, 514. 
Sarcolactic acid, 345. 
Sarracenia purpurea, 399. 
Sarsaparilla, 424. 
Sarzas radix, 424. 
Sassafras, 474. 
medulla, 407. 
oil, 474. 
pith, 407. 
Sassafrol, 474. 
Saturated solutions, hoiling-points 
of, 525. 
Saturating power of citric acid, 
322, 658. 
of tartaric acid, 318, 658. 
Saturation, 69. 
tables, 318, 322, 658. 
Saturn, 207. 
Saturnine colic, 207. 
Savin oil, 474. 
Saxon blue, 486. 
Saxony blue, 486. 
Scale compounds of iron, 150. 
Scammonii, 424. 
resina, 424. 
impurities in, 653. 
Scammonin, 424. 
Seammoniol, 424. 
Scammonium, 424. 
impurities in, 653. 
Scammony, resin of, 424. 
Scandium, 661. 
Scents, 470. 
Scheele’s green, 173. 
Schist, 135. 
Schonbein’s test for hydrocyanic 
acid, 280. 
Schweinfurth green, 173. 
Science of Chemistry, 14. 
Seilla, 424. 
Scilletin, 424. 
Scillitin, 424. 
Sclerotic acid, 478. 
Sclerotinic acid, 478. 
Scoparin, 398. 
Scoparius, 398. 
Scutellaria, 401. 
Sea-salt, 80. 
Sediments, urinary, 507. 
urinary, microscopic exam- 
inations of, 508. 
Seed-lac, 486. 
Seidlitz powder, 318. 
Selenic acid, 299. 
Selenion, 661. 
Selenious acid, 299. 
Selenium, 299, 661. 
Senega, 424. 
Senna, 417. 
Sepia, 487. 
Serolin, 457. 
Serpentaria, 401. 
Serpent’s excrement, 358. 
Sesame oil, 467. 
Sesame indicum, 467. 
Sevum, 464. 
Sexivalence, 56. 
Shale, 135. 
Shark-liver oil, 467. 
Shellac, 486. 
Sherry wine, 427. 
Sliumac, 356. 
Sienna, 484. 
Sifting, an aid to an analysis, 368. 
Silica, 351. 
Silicate of aluminium, 136. 
calcium, 103, 351. 
magnesium, 351. 
Silicates, 351. 
quantitative estimation of, 610. 
tests for, 351. 
Silicic acid, 351. 
anhydride, 351. 
Siliciuretted hydrogen, 352. 
Silico-fluoride of barium, 103. 
Silicon chloride, 352. 
derivation of word, 33. 
fluoride, 352. 716 
INDEX. 
Silicon hydride, 352. 
oxide, 351. 
Silver, 212. 
ainmonio-nitrate, 174, 203. 
analytical reactions of, 215. 
antidotes to nitrate of, 216. 
arseniate, 174, 215. 
arsenite, 174. 
bromide, 215. 
chloride, 213. 
chromate, 215. 
citrate, 323. 
cyanide, 216, 279. 
by cupellation, estimation of, 
599. _ 
derivation of word, 33. 
extraction of, 212. 
German, 232. 
iodide, 215. 
nitrate, 212, 213, 599. 
diluted, 214, 599. 
moulded, 214, 599. 
oxalate, 313. 
oxide, 215, 598. 
phosphate, 216. 
pure, 213. 
quantitative estimation of, 598. 
standard solution of nitrate of, 
567. 
sulphide, 216. 
sulphite, 304. 
tartrate. 319. 
tree, 216. 
volumetric estimation of, 598. 
Sinalbin, 453. 
Sinapine, 453. 
Sinapis, 453. 
impurities in, 654. 
Sinigrin, 453. 
Sinistrin, 425. 
Siphon (vide Syphon). 
Size, 460. 
Skullcap, 401. 
Slaked lime, 105. 
Slate, 135. 
Smalt, 230, 487. 
Smilacin, 424. 
Smilax officinalis, 424. 
Snakeroot, black, 400. 
Virginia, 400. 
Soap, ammonium, calcium, Castile, 
green, hard, Marseilles, mot- 
tled, potassium, sodium,soft, 
. 463, 464. 
Soap-bark, 424. 
-curd, 464. 
-stone, 487. 
-wort, 424. 
Socaloin, 452. 
Soeatrine aloes, 452. 
“Soda/’ 312, 561. 
-alum, 136. 
-ash, 86, 561. 
caustic, 81. 
Soda, 81. 
caustica, 81. 
impurities in, 654. 
tcirtarata, 85. 
Soda-lime, 615. 
-powders, 86. 
solution of chlorinated, 86, 
580. 
standard solution of, 564. 
valerianate, 358. 
volumetric estimation of, 
560. 
-water, 85. 
Sod@e (vide Sodii). 
Sodii ucetas, 82. 
impurities in, 654. 
arsenias, 166. 
impurities in, 654. 
benznas, 333. 
impurities in, 654. 
bicurbonas, 82. 
impurities in, 654. 
venulis, 83. 
bisidphis, 303. 
impurities in, 654. 
volumetric estimation of, 
569. 
borax, 330. 
impurities in, 654. 
bromidum, 87, 267, 569. 
impurities in, 654. 
volumetric estimation of, 
569. 
carbonas, 83, 309. 
impurities in, 654. 
exsiecatus, 83. 
cldoras, 87, 291. 
impurities in, 654. 
chlorates, liquor, 86, 580. 
chloridum, 80. 
impurities in, 654. 
citro-tartras effervescens, 86. 
hypophosphis, 341. 
impurities in, 654. INDEX 
717 
Sodii hypomlphis, 342. 
impurities in, 654. 
volumetric estimation of, 
573. 
iodidum, 87. 
impurities in, 654. 
liquor, 81. 
ultras, 282. 
impurities in, 654. 
pliosphas, 110. 
impurities in, 651. 
pyrnphosphas, 350. 
impurities in, 654. 
scdicylas, 451. 
impurities in, 654. 
santoninas, 423. 
impurities in, 655. 
silicatis, liquor, 352. 
sulphas, 263. 
impurities in, 655. 
sulphis, 303. 
impurities in, 655. 
volumetric estimation of, 
5/4. 
sulphocarbolas, 450. 
impurities in, 655. 
valerianas, 353. 
Sodic carbonate, etc. (vide Salts of 
Sodium). 
Sodio-citrate of iron, 152. 
-tartrate of iron, 152. 
Sodium, 80. 
acetate, 82. 
acid carbonate, 82, 560. 
su lphate, 263. 
tartrate, 79. 
analytical reactions of, 87. 
and aluminium double chlo- 
ride, 135. 
antimoniate, 87. 
arseniate, 166. 
arsenite, 166. 
benzoate, 333. 
benzoldisulphonate, 450. 
bicarbonate, 82. 
chemically pure, 561. 
bisulphite, 303, 574. 
bromate, 87, 268. 
bromide, 87, 268. 
carbonate, 86, 309, 560. 
chemically pure, 561. 
dried, 84. 
manufacture of, 86, 309. 
carbonates, 560. 
Sodium, carbonates, volumetric 
analysis of, 560. 
chlorate, 87, 291. 
chloride, 80. 
eholate, 464. 
citrate, 87. 
derivation of word, 31. 
ethylate, 428. 
flame, 87. 
glycocholate, 464. 
hydrate, 81. 
hypochlorite, 86. 
hypophosphite, 341. 
hyposulphite, 342. 
iodate, 87. 
iodide, 87. 
manganate, 87. 
molybdate, 329. 
nitrate, 81, 282. 
other compounds of, 87. 
oxalate, 313. 
permanganate, 87. 
phosphate, lit). 
how prepared from phos- 
phate of calcium, 110. 
potassium and ammonium, 
separation of, 99. 
pyroarseniate, 166. 
pyrophosphate, 350. 
quantitative estimation of, 560, 
586. 
salicylate, 451. 
salts, analogy of, to potassium 
salts, 87. 
sources of, 80. 
santoninate, 423. 
sulphate, 263. 
sulphite, 303, 574. 
sulphocarbolate, 450. 
taurocholate, 464. 
valerianate, 358. 
Soft soap, 463. 
Soils, analysis of, 635. 
Sol an i a, 398. 
Solan id ine, 398. 
Solanine, 398. 
Solatium dulcamara, 398. 
tuberosum, 398. 
starch of (fig.), 403. 
Solazzi juice, 421. 
Solder, 206, 238. 
Solid, definition of, 57. 
fats, 462. 
potash, 67. 718 
INDEX 
Solids lighter than water, to take 
the specific gravity of, 546. 
to take the specific gravity of, 
544 et seq. 
Solubility of carbonic acid gas in 
water, 85. 
of gases in liquids, 85. 
of precipitates in strong solu- 
tions of salts, 279. 
or insolubility of salts in 
water, Table of, 363. 
Soluble cream of tartar, 331. 
glass, 352. 
stareh, 406. 
substances, to take the specific 
gravity of, 546. 
tartar, 73. 
Solution of acetate of ammonium, 
91. 
of potassium, 68. 
of sodium, 82. 
albumen, 455. 
ammonia, 90. 
ammonio-nitrate of silver, 174, 
203. 
-sulphate of copper, 174, 
203. 
-sulphate of magnesium, 
119, 608. 
arsenic in acid, 165. 
in alkali, 164. 
boracie acid, 330. 
bromine, 268. 
carbonate of ammonium, 91. 
of magnesium, 117. 
chloride of ammonium, 89. 
of antimony, 179. 
of barium, 101. 
of calcium, 104. 
saturated, 104. 
of gold, 242. 
of tin, 238. 
of zinc, 130. 
chlorinated lime, 580. 
soda, 86, 580. 
chlorine, 28. 
citrate of ammonium, 93. 
of magnesium, 118. 
ferridcyanide of potassium, 
339. 
ferrocyanide of potassium, 
339' 
gelatin, 459. 
iodate of potassium, 74, 293. 
Solution of iodide of mercury 
and potassium, 194. 
iodide of potassium, 74. 
of potassium and bismuth, 
562. 
iodine, 269. 
lime, 105. 
litmus, 94. 
nitrate of mercury, 195. 
oxalate of ammonium, 94. 
perchloride of iron, 144. 
of mercury, 2ul. 
of platinum, 243. 
pernitrate of iron, 154. 
persulphate of iron, 146. 
phosphate of sodium, 110. 
phosphoric acid, 326. 
potash, 61, 67, 
potassio-cupric tartrate, 630. 
red prussiate of potash, 339. 
soda, 81. 
strychnia, 389. 
subacetate of lead, 208. 
sulphate of calcium, 113. 
of indigo, 287. 
of iron, 140. 
sulphide of ammonium, 94. 
sulphydrate of ammonium, 94. 
tartaric acid, 316. 
yellow prussiate of potash, 
339. 
Sonnenschein’s process for poison- 
ous alkaloids, 501. 
Soot, 30. 
Soubresauls, 277. 
Source of heat, 17. 
Sovereign, weight of the, 242. 
Soymida febrifugu, 401. 
Spanish liquorice, 421. 
Spar, fluor-, 340. 
heavy, 101. 
Sparteia or sparteine, 398. 
Spathic iron ore, 139. 
Spearmint oil, 493. 
Specific gravity, 541. 
of gases, 547. 
of liquids, 542. 
of official liquids, 543. 
of oxygen, 24. 
of powders, 545. 
of solids, 544. 
lighter than water, 
546. 
of soluble substances, 546. INDEX. 
719 
Specific heat, 127. 
weight, 541. 
Spectroscope, 491. 
Spectrum analysis, 491. 
Specular iron ore, 138. 
Speculum metal, 238. 
Speiss, 232. 
Spermaceti, 465, 526. 
Spermatozoa, in urine, 514. 
Sperm oil, 465. 
Spigelia, 398. 
Spircea ulinaria, 423. 
Spirit of French wine, 431. 
methylated, 439. 
mindererus, 91. 
myrcia, 427. 
of nitrous ether, 348, 435. 
adulterated, 440. 
proof, 427. 
pyroxylic, 439. 
rectified, 427. 
of turpentine, 475. 
of wine, 427. 
impurities in, 622. 
wood-, 439. 
Spirits, 517. 
analysis of, 632. 
Spiritus at her is, 434. 
compositus, 434. 
nitrosi, 434. 
impurities in, 655. 
ammonia;, 92. 
5 impurities in, 655. 
volumetric estimation of, 
557. 
aromaticus, 92. 
impurities in, 621. 
fcetidus, 92. 
anisi, 471. 
aurantii, 471. 
cajuputi, 472. 
cinnamomi, 472. 
cliloroformi, 443. 
frumenti, 427, 431. 
impurities in, 655. 
gaultherice, 470. 
j uni peri, 470. 
lavanduler, 470. 
limonis, 470. 
menthce piperita;, 470. 
myreice, 427. 
myristicce, 470. 
odoratus, 470. 
redifiratus, 571. 
Spiritus rosmarivi, 470. 
tenuior, 427. 
vini gallici, 431. 
impurities in, 655. 
Spodumene, 223. 
Spogel seeds, 407. 
Spongy platinum, 245. 
Spontaneous combustion, 155. 
Spotted cranesbill, 356. 
Spruce fir, 479. 
Spurge laurel, 479. 
Squalus carchurius, 467. 
Squill, 414. 
Standard gold, 241. 
Standard solution of hyposul- 
phite of sodium, 578. 
of iodine, 579. 
of nitrate of silver, 567. 
of oxalic acid, 556. 
of red chromate of potas- 
sium, 575. 
of soda, 564. 
of sulphuric acid, 563. 
Stannate of sodium, 239. 
Stannates, 239. 
Stannic acid, 239. 
anhydride, 239. 
chloride, 239. 
oxide, 239. 
sulphide, 240. 
anhydrous, 240. 
Stannous chloride, solid, 238. 
hydrate, 240. 
oxide, 240. 
sulphide, 240. 
Stannum, 34. 
Staphisagria, 395. 
Star-anise oil, 471. 
Starch, 401. 
blue, 401. 
cellulose, 405. 
gelatinized, 404. 
iodized, 405. 
soluble, 406. 
quantitative estimation of, 630. 
-sugar, 413. 
Starches, microscopy of, 402. 
Stas’s process for poisonous alka- 
loids, 500. 
Stavesacre, 395. 
Steam-bath, 583. 
Stearic acid, 465, 468. 
Stearine, 465. 
Steatite, 487. 720 
INDEX. 
Steel, 139. 
wine, 152. 
Stick-lac, 486. 
liquorice, 421. 
Stibium, 32. 
Still, 125. 
Stillingia, 401. 
Stone-coal, 237. 
red, 485. 
Storax, 483. 
Stout, 427. 
Stramonii folia, 396. 
semen, 396. 
Strasburg turpentine, 475. 
Strawberry, 320, 345, 411. 
Stream tin, 237. 
Strontianite, 225. 
Strontium, 225. 
analytical reactions of, 225. 
carbonate, 225. 
derivation of word, 33. 
flame, 225. 
nitrate, 225. 
sulphate, 225. 
Structure of flame, 23. 
Strychnia or strychnine, 388. 
impurities in, 655. 
analytical reactions of, 389,497. 
in organic mixtures, detection 
of, 497. 
Strychnina, 388. 
impurities in, 655. 
Strychnines sulphas, 389. 
Strychnos Ignatius, 388. 
nux vomica, 388. 
Styptic collodion, 410. 
Styracin, 483. 
Styrax, 483. 
benzoin, 483. 
preeparatus, 483. 
Styrol, 483. 
Styrone, 483. 
Subacetate of copper, 188. 
of lead, 207. 
Subcarbonate of iron, 141. 
Subchloride of mercury, 198. 
Sublimation, 91, 201. 
Sublimed sulphur, 298. 
Subnitrate of bismuth, 247. 
Substances readily deoxidized, 
quantitative estimation of, 
578. 
oxidized, quantitative estima- 
tion of, 572. 
Substitution-products, 442. 
Succi, 517. 
Succinate of potassium, 352. 
Succinic acid, 352. 
Succinum, 352. 
Succus limonis, 322. 
Sucrose, 411. 
Suet, 464. 
prepared, 464. 
Sugar, 410. 
amount in various fruits, 412. 
brown, 411. 
candy, 411. 
cane-, 411. 
detection of, in urine, 504. 
grape-, 411. 
inverted-, 411. 
loaf-, 411. 
maple-, 411. 
milk-, 412. 
moist, 411. 
of gelatin, 464. 
lead, 207. 
quantitative estimation of, 
630. 
tests for, 411. 
Sulphate of aluminium, 136. 
and ammonium, 135. 
ammonium, 89. 
and iron, 136. 
barium, 102. 
bismuth, 249. 
cadmium, 246. 
calcium, 103, 113. 
chromium, 235. 
cinchonine, 387. 
cobalt, 230. 
copper, 188. 
anhydrous, 188. 
cupr- diammon - diammonium 
203. 
indigo, 287. 
iron, 140, 577. 
precipitated, 141. 
solution of, 147. 
lead, 211. 
magnesium, 115, 589. 
manganese, 229. 
mercury, 196. 
potassium, 72, 284. 
quinine, 384. 
sodium, 86, 263. 
strontium, 225. 
zinc, 129. INDEX. 
721 
Sulphates, 304. 
analytical reactions of, 307. 
quantitative estimation of, 
605. 
Sulphethylic acid, 433. 
Sulphide of allyl, 453. 
ammonium, 94. 
antimony, 176, 180. 
arsenicum, 164, 172. 
native, 163. 
barium, 101. 
bismuth, 250. 
cadmium, 246. 
calcium, 300. 
cobalt, 230. 
copper, 188. 
iron, 143. 
lead, 211. 
native, 206. 
manganese, 229. 
mercury, 203. 
native, 191. 
nickel, 232. 
potassium, 67. 
silver, 216. 
native, 213. 
tin, 239. 
zinc, 133. 
native, 128. 
Sulphides, 298. 
analytical reactions of, 301. 
native, 164. 
quantitative estimation of, 604. 
Snlphindigotic acid, 287. 
Sulphindylic acid, 287. 
Sulphite of barium, 304. 
calcium, 303. 
magnesium, 303. 
potassium, 303, 574. 
silver, 304. 
sodium, 303, 574. 
Sulphites, 303. 
analytical reactions of, 303. 
quantitative estimation of, 
574, 605. 
Snlphocarbolates, 450. 
Sulphocarbolic acid, 450. 
Sulphocarbonates, 310. 
Sulphocarbonic anhydride, 310. 
Sulphocyanate of aerinyl, 453. 
allyl, 453. 
butyl, 438. 
iron, 158. 
Sulphocyanates, 353. 
Sulphocyanic acid, 353. 
Sulphocyanides, 353. 
Sulphocyanogen, 353. 
Sulphophenates, 450. 
Sulphophenic acid, 450. 
Sulphosalicylic acid, 451. 
Sulphostannates, 240. 
Sulphovinic acid, 433. 
Sulphur, 30. 
adulteration of, 301. 
allotropy of, 298. 
analytical reactions of, 301. 
arsenic in, 172. 
bromide, 301. 
chloride, 301. 
derivation of word, 31. 
estimation of, 604. 
flowers of, 298. 
hypochloride, 301. 
iodide, 271, 301. 
liver of, 67. 
milk of, 300. 
oxvacids, 343. 
plastic, 298. 
precipitated, 300. 
roll, 298. 
sublimed, 298. 
Sulphur lotum, 298. 
impurities in, 655. 
prcecipitatum, 300. 
impurities in, 655. 
sublimatum, 298. 
impurities in, 656. 
Sulphurated antimony, 179. 
lime, 112. 
potassa, 67. 
Sulphurets (vide Sulphides). 
Sulphuretted hydrogen, 298. 
Sulphuric acid, 304. 
antidotes to, 308. 
aromatic, 307. 
dilute, 307. 
fuming, 307. 
Nordhausen, 307. 
in organic mixtures, de- 
tection of, 495 
purification of, 307. 
standard solution of, 563. 
volumetric estimation of, 
566. 
anhydride, 307. 
Sulphur is iodidum, 271. 
impurities in, 655. 
Sulphurous acid, 30, 302. 722 
INDEX. 
Sulphurous acid, volumetric esti- 
mation of, 572. 
anhydride, 302. 
Sulpliydrate of ammonium, solu- 
tion of, 94. 
Sulphydric acid, 95, 298. 
Sumach, 356. 
Sumatra camphor, 476. 
Sumbul, 481. 
Superphosphate of lime, 324. 
Supporters of combustion, 22. 
Suppositories, 517. 
Surface, unit, 531. 
Surgery, 14. 
Swamp sassafras, 401. 
Sweetbread, 461. 
Sweet spirit of nitre, 348, 434. 
adulterated, 440. 
Sylvie acid, 478. 
Symbol, function of, 41, 52. 
Symbols of elements, 30, 41. 
illustration of chemical action 
by, 46. 
Sympathetic inks, 231. 
Synaptase, 416. 
Synthesis, 60. 
Syphon, 108. 
Syrup of iodide of iron, 30. 
Syrups, 517. 
specific gravities of, 544. 
Syrupi, impurities in, 656. 
Syrupus, 471. 
acidi hydriodici, 270. 
impurities in, 656. 
auruntil, 471. 
florum, 471. 
calcii lactophosphatis, 110. 
calcis, 106. 
Jerri bromidi, 144. 
impurities in, 656. 
iodidi, 30, 144. 
impurities in, 656. 
phosphalis, 143. 
quinines et strychnince phos- 
phatum, 390. 
hypophosph i turn ,341. 
cum ferro, 341. 
Tabacum, 397. 
Tables, various (vide Appendix). 
Talc, 135. 
Tamarindus, 321. 
impurities in, 656. 
Tanacetic acid, 424. 
Tanacetum, 424. 
Tannic acid, 354. 
Tanning, 354. 
Tansy, 424. 
tar, 481. 
Tantalum, CGI. 
Tapioca, 402. 
starch (fig.), 403. 
Taraxaci radix, 401. 
Taraxacin, 401. 
Tartar, meaning of, 316. 
cream of, 72, 79, 315. 
emetic, 178, 316. 
estimation of antimony 
in, 594. 
Tartarated antimony, 178. 
Tartaric acid, 315, 316. 
saturating power of, 318, 636. 
solution of, 319. 
Tartarus boraxatus, 331. 
Tartrate of ammonium, 97. 
antimony and potass., 178, 316. 
calcium, 319. 
potassium, acid, 72, 79. 
neutral. 72, 316. 
and sodium, 84, 317. 
silver, 319. 
sodium, 79. 
Tartrates, 73, 315. 
analytical reactions of, 319. 
volumetric estimations of, 561. 
Taurine, 464. 
Taurocholates, 464. 
Teal oil, 467. 
Telini fly, 476. 
Tellurium, 299, 661. 
Temperature, correction of volume 
of gas for, 547. 
measurement of, 522. 
Terbium, 661. 
Terebinthiva, 475. 
canadensis, 474. 
Terpenes, 469. 
Terra di sienna, 485. 
Ten a japonica, 355. 
Testa pnrparata, 110. 
Test-papers, 94. 
-tube, 16. 
Tetramines, 378. 
Tetrathionic acid, 343. 
Tetrvl, 438. 
Thalleiochin, 385. 
Thallium, 661. 
Thebaine, 380. INDEX. 
723 
Theia, 39S. 
Theine, 398. 
Thenard’s blue, 487. 
Theobroma oil, 465. 
Theobroniate of glyceryl, 465. 
Therapeutics, definition and deri- 
vation of, 14. 
Ttieriaca, 414. 
Thermolysis, 550. 
Thermometer, 523. 
Celsius’s, 523. 
Centigrade, 523. 
Fahrenheit’s, 523. 
Reaumur’s, 523. 
Thermometric scales, conversion 
of degrees of, 524. 
Thionic acids, 343. 
Thiosulphates, 342. 
Thorinum, 661. 
Thorium, 661. 
Thorn-apple, 396. 
Thoronghwort, 400. 
Thresh’s alkaloidal reagent, 502. 
Thus americanum, 481. 
Thuja, 474. 
Thyme, oil of, 475. 
Thymene, 475. 
Try mol, 473, 475. 
impurities in, 656. 
Thymus vulyaris, 473. 
Tiglic acid, 466. 
Tin, 237. 
amalgam, 238. 
analytical reactions of, 239. 
antidotes to, 241. 
block, 237. 
chloride of, 238. 
derivation of word, 34. 
dropped or grain, 238. 
foil, 238. 
granulated, 23S. 
oxide, 239. 
perch loride, 239. 
plate, 238. 
prepare-liquor, 239. 
-stone, 237. 
tacks, 238. 
white cobalt, 230. 
Tincal, 330. 
Tinctura cannabis iurlicce, 478. 
Jerri acetatis, 147. 
impurities in, 656. 
chloridi, 146. 
impurities in, 656. 
Tinctura iocli, 271, 580. 
Tinctures, 146. 
Tinctures, 146, 517. 
Tinnevelly senna, 417. 
Tinospora cordifolia, 400. 
Titanium, 661. 
Tobacco, 397. 
I'oddalice radix, 401. 
Tolen, 483. 
Tolu, balsam of, 483. 
Toluol, 448. 
Toxicodendrie acid, 357. 
Toxicology, 492. 
Tragacanth, 112. 
Tragacantha, 112. 
Treacle, 414. 
Triads, 121. 
Triamines, 378. 
Triangle, wire, 98. 
Tribasic acids, 260. 
Tribasylous radicals, 260. 
Trichloro-methylbenzol, 333. 
Triethylamine, 378. 
Triethylia, 378. 
Trinitro-carbolic acid, 450. 
Trinitrocellulin, 409. 
Triphane, 223. 
Tripoli, 351. 
Trithionic acid, 343. 
Triticum repens, 401. 
starch of (fig.), 403. 
Trituratio elaterini, 419. 
Trityl, 438. 
Tritylia, 378. 
Trivalence, 55. 
Trivalent radicals, 55, 121. 
Troches, 517. 
Trochisci. sodii santoninatis, 423. 
Tropate of atropia, 392. 
Tropic acid, 392. 
Tropine, 392. 
Tube-funnels, 96. 
Tubes for collecting gases, 18. 
glass (vide Glass Tubes). 
Tungsten, 661. 
Turgite, 149. 
Turkey corn, 395. 
Tumeric, 485. 
oil, 475. 
-paper, 94, 331. 
Turmerol, 475. 
Turnbull’s blue, 339, 486. 
Turpentine, 474. 
American, 475. 724 
INDEX 
Turpentine, Bordeaux, 475. 
Canadian, 474. 
Chian, 474. 
French, 475. 
rectified oil of, 475. 
spirit of, 475. 
Strasburg, 475. 
Venice, 474. 
Turpeth mineral, 197. 
Turps, 475. 
Tylophora asthmatica, 396. 
Type-metal, 176, 206. 
Types, chemical, 375. 
Typical formulae, 438. 
Ulmi cortex, 355. 
fulvce, 407. 
Ulmus, 407. 
Ultimate analysis, 611. 
Ultramarine blue, 486. 
green, 487. 
Ultraquinine, 388. 
Umbelliferone, 481. 
Umber, 487. 
burnt, 487. 
Uncaria gambler, 355. 
Unguenlum cerussce, 207. 
hydrargyri, 191. 
ammoniati, 202. 
iodidi rubri, 195. 
nitratis, 196. 
subchloridi, 199. 
iodi, 271. 
plumbi, carbonatis, 207. 
veratrince, 399. 
Units of capacity, 531. 
surface, 531. 
weight, 531. 
Univalence, 55. 
Univalent radicals, 55, 121. 
Uralium, 661. 
Uranium, 661. 
Urari, 390. 
Urate of lithium, 224. 
Urates, 358. 
Urceola elastica, 483. 
Urea, 335, 505. 
artificial, 335, 505. 
Uric acid, 358, 508. 
Urinary calculi, 514. 
examination of, 514. 
deposits or sediments, plates 
of (vide 509 et seq.). 
sediments. 507. 
Urinary sediments, microscopical 
examination of, 508. 
Urine, 503. 
diabetic, 412, 504, 630. 
estimation of urea in, 505. 
morbid examination of, 503. 
Urinometer, 544. 
Ustilago, 478. 
Uvce, 412. 
Uva ursi, 356. 
Valerene, 475. 
Valerian oil, 475. 
Valeriana, 475. 
Valerianate of ammonium, 360. 
amyl, 446. 
iron, 359. 
quinia, 384. 
sodium, 358. 
zinc, 133, 359. 
Valerianates, 358. 
Valerianic acid, 358, 468. 
Valerol, 475. 
Vanadates, 330. 
Vanadinite, 330. 
Vanadium, 330, 661. 
relationship to nitrogen, phos- 
phorus, and arsenicum, 330. 
Vanilla, 483. 
Vanillic acid, 360. 
Vanilline, 360. 
Vapor acidi hydrocyanici, 279. 
chlori, 29. 
conice, 395. 
iodi, 269. 
Vapor-density, 548. 
Variolaria, 486. 
Vaseline, 448. 
Vegetable albumen, 459. 
and animal life, relation of, 19. 
casein, 401, 459. 
crocus, 485. 
tibrin, 401, 459. 
gelatin, 459. 
green, 486. 
jelly, 407. 
oil, 462. 
rouge, 486. 
substances, 37 6 et seq. 
Venetian red, 150. 
Venice turpentine, 474. 
Veratralbia, 396. 
Veratri viridi radix, 396. 
Veratria or veratrine, 399. INDEX. 
725 
Veratrina, 399. 
impurities in, 656. 
Verutrum album, 396. 
viride, 396. 
Verdigris, 188. 
Vermilion, 203. 
Veronica virginica, 401. 
Viburnin, 401. 
Viburnum, 401. 
Vinegar, 295. 
estimation of mineral acids in, 
605. 
impurities in, 656. 
of cantharides, 295. 
squill, 295. 
Vinum album, 427, 632. 
impurities in, 656. 
antimonii, 179. 
Jerri amarum, 153. 
Jerri citrails, 152. 
Jortius, 427. 
impurities in, 656. 
rabnim, 427, 632. 
impurities in, 656. 
xericum, 427. 
Viola tricolor, 451. 
Virginia snakeroot, 401. 
Vi tel I us, 456. 
Vitriol, blue, 141. 
green, 141. 
oil of, 307. 
white, 141. 
Volatile oils (vide Oils). 
Volatility of salts of ammonium, 
97. 
Volatilization, 98. 
Volcanic ammonia, 89. 
Volume, combination by, 52. 
of gas, corrections of, 518. 
molecular, 54. 
Volumetric analysis, 554. 
estimation of acetate of lead, 
559. 
acetic acid, 565. 
acids, 563. 
alkalies, 556. 
alkaline carbonates, 560. 
ammonia solutions, 557. 
arseniate of iron, 576. 
arsenic and arsenical so- 
lutions, 573. 
bisulphite of sodium, 574. 
borax, 559. 
bromides, 569. 
Volumetric estimation of bro- 
mide of ammonium, 569. 
of potassium, 569. 
sodium, 570. 
carbonate of ammonium, 
558. 
chlorides, 600. 
chlorinated lime, 580. 
chlorinated soda, 580. ' 
chlorine, 580. 
citrate of potassium, 561. 
citrates, 561. 
cyanide of potassium, 567. 
cyanides, 567. 
hydrobromic acid, 565. 
hydrochloric acid, 565. 
hydrocyanic acid, 567. 
hyposulphite of sodium, 
573. 
iodide of potassium, 571. 
iodine, 579. 
lactic acid, 565. 
lead solutions, 559. 
lime solutions, 559. 
magnetic oxide of iron, 
577. 
nitric acid, 565. 
official compounds, 557, 
565, 567, 570, 575, 578. 
permanganate of potas- 
sium, 562. 
phosphate of iron, 576. 
potash, 560. 
saceharated carbonate of 
iron, 577. 
soda, 560. 
sugar, 630. 
sulphate of iron, 577. 
sulphite of potassium, 
574. 
of sodium, 574. 
sulphides, 604. 
sulphuric acid, 566. 
sulphurous acid, 572. 
syrup of bromide of iyon, 
570. 
hydriodic acid, 570. 
tartrates, 561. 
tincture of iodine, 580. 
solutions, 556, 564, 567, 572. 
Vulcanite, 483. 
Vulcanized India-rubber, 483. 
Wahoo-bark, 400. 726 
INDEX. 
Washing-bottles, 107, 583. 
precipitates, 107, 583. 
Warmth of animals, how kept up, 
19. 
Water, 126. 
aerated, 85. 
ammonia in potable, 558. 
aspirator, 306. 
-bath, 583. 
boiling-point of, 525. 
chalybeate, 139. 
cologne, 470. 
composition of, 22. 
crystallization, 84. 
quantitative estimation of, 
610. 
cubic inches of, in a gallon, 
548. 
distilled, 126. 
evaporation of, 70. 
formation of, expressed by 
symbols, 43. 
hardness of, 312. 
hemlock, 472. 
impurities in, 126, 616. 
lime-, 105. 
nitrites in, 348. 
of crystallization, 84. 
-oven, 583. 
oxygenated, 102. 
purification of, 124, 312. 
softness of, 312. 
type, 375. 
weight of 1 cubic inch of, 
548. 
of minim, drachm, ounce, 
pint, and gallon, 538. 
Wax, 465. 
Weighing-tubes, 583. 
Weight, 528. 
estimation of, 528. 
molecular, 54. 
of air, 548. 
hydrogen, 549. 
water, 541. 
specific, 541. 
Weights, atomic, 51. 
and measures of the British 
Pharmacopoeia of 1867, 538. 
of the metric decimal 
system, 533 el seq. 
U. S. Pharmacopoeia of 
1870, 529. 
balance, 528. 
Weights of litres at different tem- 
peratures, 532. 
relation of metrical, to the 
weights of the U. S. Phar- 
macopoeia, 535. 
relative, 52. 
Weld, 485. 
Welding, 245. 
Wheat-starch (fig.), 403. 
Wheaten flour, 401. 
Whey, 412, 457. 
Whisky, 427. 
White arsenic, 164. 
indigo, 287. 
lead, 206. 
oak, 354. 
pepper, 397. 
pigments, 487. 
precipitate, fusible, 202. 
infusible, 202. 
resin, 478. 
vitriol, 141. 
wax, 465, 526. 
Whiting, 108. 
Whortleberry, sugar in, 412. 
Wild black cherry, 417. 
indigo, 400. 
marjoram, 473. 
Willow-bark, 344, 422. 
Wine, 427, 632. 
antimonial, 179. 
iron, 152. 
orange, 427. 
sherry, 427. 
steel, 152. 
W interberrv, 356. 
Wintergreen, oil of, 446. 
Wire-gauze tray, 28. 
triangle, 98. 
Witch-hazel, 400. 
Witlierite, 101. 
Wood-charcoal, 110. 
creasote, 449. 
naphtha, 439. 
oil, 481. 
specific gravity of, 547. 
spirit, 439. 
tar, 481. 
Woody nightshade, 398. 
Wormseed, American, 475. 
Levant, 423. 
Wormwood, 472. 
Wourali, 390. 
Wourara, 390. INDEX. 
727 
Wrought iron, 139. 
Xantiiin, 516. 
Xanthorrhiza apiifolia, 393. 
Xanthoxylon, 393. 
fmxineum, 393. 
Xylol, 448. 
Yard, 538. 
Yeast, 426. 
Yelk of egg, 456. 
Yellow chromate of potassium, 
234. 
coloring-matters, 484. 
dock, 335. 
ochre, 484. 
oxide of mercury, 201. 
parilia, 393. 
prussiate of potassium, 276, 
339. 
root, 393. 
sienna, 484. 
wax, 465, 526. 
wood, 484. 
Yolk of egg, 456. 
Ytterbium, 661. 
Yttrium, 661. 
Zaffre, 230. 
Zanaloin. 452. 
Zanzibar aloes, 452. 
Zea may*, starch of (tig.), 403. 
smut, 470. 
Zinc, 128. 
acetate, 131. 
analytical reactions of, 133. 
antidotes to, 134. 
bromide, 131. 
carbonate, 128, 131. 
chloride, 129. 
derivation of word, 32. 
Zinc, detection of, in presence of 
aluminium and iron, 159. 
-ethyl, 437. 
ferrocyanide, 134. 
granulated, 20. 
hydrate, 134. 
in organic mixtures, detection 
of, 495. 
iodide, 131. 
oxide, 132. 
Hubbuck’s, 132. 
quantitative estimation of, 590. 
sulphate, 129. 
sulphide, 133. 
native, 128. 
valerianate, 133, 359. 
white, 131. 
Zinci acetas, 131. 
impurities in, 656. 
bromidum, 131. 
impurities in, 656. 
carbonas prcecipitatus, 131. 
impurities in, 657. 
chlovidi, liquor, 130. 
chloridum, 129. 
impurities in, 657. 
iodidum, 131. 
impurities in, 657. 
oxidum, 132. 
impurities in, 657. 
phoxphidum, 325. 
impurities in, 657. 
sulphas, 129. 
impurities in, 657. 
valerianas, 133, 359. 
impurities in, 657. 
Zincum, 128. 
impurities in, 657. 
granulatum, 20. 
Zingiber, 475. 
Zirconium, 661. 
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