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Title: Elements of Chemistry,

Author: Antoine Laurent Lavoisier

Translator: Robert Kerr

Release date: December 28, 2009 [eBook #30775]
Most recently updated: January 5, 2021

Language: English

Other information and formats: www.gutenberg.org/ebooks/30775

Credits: Produced by Mark C. Orton, Josephine Paolucci and the
Online Distributed Proofreading Team at https://www.pgdp.net

*** START OF THE PROJECT GUTENBERG EBOOK ELEMENTS OF
CHEMISTRY, ***

ELEMENTS
OF

CHEMISTRY,
IN A

NEW SYSTEMATIC ORDER,

CONTAINING ALL THE

MODERN DISCOVERIES.

ILLUSTRATED WITH THIRTEEN COPPERPLATES.

By Mr LAVOISIER,
Member of the Academy of Sciences, Royal Society of Medicine, and
Agricultural Society of Paris, of the Royal Society of London, and
Philosophical Societies of Orleans, Bologna, Basil, Philadelphia, Haerlem,
Manchester, &c. &c.

TRANSLATED FROM THE FRENCH,

By ROBERT KERR, F.R. & A.SS.E.
Member of the Royal College of Surgeons, and Surgeon to the Orphan
Hospital of Edinburgh.
EDINBURGH: printed for WILLIAM CREECH, and sold in london by g.
g. and j. j. robinsons.
MDCCXC.

ADVERTISEMENT OF THE TRANSLATOR.
The very high character of Mr Lavoisier as a chemical philosopher, and the
great revolution which, in the opinion of many excellent chemists, he has
effected in the theory of chemistry, has long made it much desired to have a
connected account of his discoveries, and of the new theory he has founded
upon the modern experiments written by himself. This is now accomplished
by the publication of his Elements of Chemistry; therefore no excuse can be
at all necessary for giving the following work to the public in an English
dress; and the only hesitation of the Translator is with regard to his own
abilities for the task. He is most ready to confess, that his knowledge of the
composition of language fit for publication is far inferior to his attachment
to the subject, and to his desire of appearing decently before the judgment
of the world.
He has earnestly endeavoured to give the meaning of the Author with the
most scrupulous fidelity, having paid infinitely greater attention to accuracy
of translation than to elegance of stile. This last indeed, had he even, by
proper labour, been capable of attaining, he has been obliged, for very
obvious reasons, to neglect, far more than accorded with his wishes. The
French copy did not reach his hands before the middle of September; and it
was judged necessary by the Publisher that the Translation should be ready
by the commencement of the University Session at the end of October.
He at first intended to have changed all the weights and measures used by
Mr Lavoisier into their correspondent English denominations, but, upon
trial, the task was found infinitely too great for the time allowed; and to
have executed this part of the work inaccurately, must have been both
useless and misleading to the reader. All that has been attempted in this way
is adding, between brackets ( ), the degrees of Fahrenheit's scale
corresponding with those of Reaumeur's thermometer, which is used by the
Author. Rules are added, however, in the Appendix, for converting the
French weights and measures into English, by which means the reader may
at any time calculate such quantities as occur, when desirous of comparing
Mr Lavoisier's experiments with those of British authors.

By an oversight, the first part of the translation went to press without any
distinction being preserved between charcoal and its simple elementary
part, which enters into chemical combinations, especially with oxygen or
the acidifying principle, forming carbonic acid. This pure element, which
exists in great plenty in well made charcoal, is named by Mr Lavoisier
carbone, and ought to have been so in the translation; but the attentive
reader can very easily rectify the mistake. There is an error in Plate XI.
which the engraver copied strictly from the original, and which was not
discovered until the plate was worked off at press, when that part of the
Elements which treats of the apparatus there represented came to be
translated. The two tubes 21. and 24. by which the gas is conveyed into the
bottles of alkaline solution 22. 25. should have been made to dip into the
liquor, while the other tubes 23. and 26. which carry off the gas, ought to
have been cut off some way above the surface of the liquor in the bottles.
A few explanatory notes are added; and indeed, from the perspicuity of the
Author, very few were found necessary. In a very small number of places,
the liberty has been taken of throwing to the bottom of the page, in notes,
some parenthetical expressions, only relative to the subject, which, in their
original place, tended to confuse the sense. These, and the original notes of
the Author, are distinguished by the letter A, and to the few which the
Translator has ventured to add, the letter E is subjoined.
Mr Lavoisier has added, in an Appendix, several very useful Tables for
facilitating the calculations now necessary in the advanced state of modern
chemistry, wherein the most scrupulous accuracy is required. It is proper to
give some account of these, and of the reasons for omitting several of them.
No. I. of the French Appendix is a Table for converting ounces, gros, and
grains, into the decimal fractions of the French pound; and No. II. for
reducing these decimal fractions again into the vulgar subdivisions. No. III.
contains the number of French cubical inches and decimals which
correspond to a determinate weight of water.
The Translator would most readily have converted these Tables into English
weights and measures; but the necessary calculations must have occupied a
great deal more time than could have been spared in the period limited for

publication. They are therefore omitted, as altogether useless, in their
present state, to the British chemist.
No. IV. is a Table for converting lines or twelfth parts of the inch, and
twelfth parts of lines, into decimal fractions, chiefly for the purpose of
making the necessary corrections upon the quantities of gasses according to
their barometrical pressure. This can hardly be at all useful or necessary, as
the barometers used in Britain are graduated in decimal fractions of the
inch, but, being referred to by the Author in the text, it has been retained,
and is No. I. of the Appendix to this Translation.
No. V. Is a Table for converting the observed heights of water within the
jars used in pneumato-chemical experiments into correspondent heights of
mercury for correcting the volume of gasses. This, in Mr Lavoisier's Work,
is expressed for the water in lines, and for the mercury in decimals of the
inch, and consequently, for the reasons given respecting the Fourth Table,
must have been of no use. The Translator has therefore calculated a Table
for this correction, in which the water is expressed in decimals, as well as
the mercury. This Table is No. II. of the English Appendix.
No. VI. contains the number of French cubical inches and decimals
contained in the corresponding ounce-measures used in the experiments of
our celebrated countryman Dr Priestley. This Table, which forms No. III. of
the English Appendix, is retained, with the addition of a column, in which
the corresponding English cubical inches and decimals are expressed.
No. VII. Is a Table of the weights of a cubical foot and inch, French
measure, of the different gasses expressed in French ounces, gros, grains,
and decimals. This, which forms No. VI. of the English Appendix, has been,
with considerable labour, calculated into English weight and measure.
No. VIII. Gives the specific gravities of a great number of bodies, with
columns, containing the weights of a cubical foot and inch, French measure,
of all the substances. The specific gravities of this Table, which is No. VII.
of the English Appendix, are retained, but the additional columns, as useless
to the British philosopher, are omitted; and to have converted these into
English denominations must have required very long and painful
calculations.

Rules are subjoined, in the Appendix to this translation, for converting all
the weights and measures used by Mr Lavoisier into corresponding English
denominations; and the Translator is proud to acknowledge his obligation to
the learned Professor of Natural Philosophy in the University of Edinburgh,
who kindly supplied him with the necessary information for this purpose. A
Table is likewise added, No. IV. of the English Appendix, for converting the
degrees of Reaumeur's scale used by Mr Lavoisier into the corresponding
degrees of Fahrenheit, which is universally employed in Britain[1].
This Translation is sent into the world with the utmost diffidence, tempered,
however, with this consolation, that, though it must fall greatly short of the
elegance, or even propriety of language, which every writer ought to
endeavour to attain, it cannot fail of advancing the interests of true chemical
science, by disseminating the accurate mode of analysis adopted by its
justly celebrated Author. Should the public call for a second edition, every
care shall be taken to correct the forced imperfections of the present
translation, and to improve the work by valuable additional matter from
other authors of reputation in the several subjects treated of.
Edinburgh, }
Oct. 23. 1789. }

FOOTNOTES:
[1] The Translator has since been enabled, by the kind assistance of the
gentleman above alluded to, to give Tables, of the same nature with those of Mr
Lavoisier, for facilitating the calculations of the results of chemical experiments.

PREFACE OF THE AUTHOR.
When I began the following Work, my only object was to extend and
explain more fully the Memoir which I read at the public meeting of the
Academy of Sciences in the month of April 1787, on the necessity of
reforming and completing the Nomenclature of Chemistry. While engaged
in this employment, I perceived, better than I had ever done before, the
justice of the following maxims of the Abbé de Condillac, in his System of
Logic, and some other of his works.
"We think only through the medium of words.—Languages are true
analytical methods.—Algebra, which is adapted to its purpose in every
species of expression, in the most simple, most exact, and best manner
possible, is at the same time a language and an analytical method.—The art
of reasoning is nothing more than a language well arranged."
Thus, while I thought myself employed only in forming a Nomenclature,
and while I proposed to myself nothing more than to improve the chemical
language, my work transformed itself by degrees, without my being able to
prevent it, into a treatise upon the Elements of Chemistry.
The impossibility of separating the nomenclature of a science from the
science itself, is owing to this, that every branch of physical science must
consist of three things; the series of facts which are the objects of the
science, the ideas which represent these facts, and the words by which these
ideas are expressed. Like three impressions of the same seal, the word
ought to produce the idea, and the idea to be a picture of the fact. And, as
ideas are preserved and communicated by means of words, it necessarily
follows that we cannot improve the language of any science without at the
same time improving the science itself; neither can we, on the other hand,
improve a science, without improving the language or nomenclature which
belongs to it. However certain the facts of any science may be, and,
however just the ideas we may have formed of these facts, we can only
communicate false impressions to others, while we want words by which
these may be properly expressed.

To those who will consider it with attention, the first part of this treatise will
afford frequent proofs of the truth of the above observations. But as, in the
conduct of my work, I have been obliged to observe an order of
arrangement essentially differing from what has been adopted in any other
chemical work yet published, it is proper that I should explain the motives
which have led me to do so.
It is a maxim universally admitted in geometry, and indeed in every branch
of knowledge, that, in the progress of investigation, we should proceed
from known facts to what is unknown. In early infancy, our ideas spring
from our wants; the sensation of want excites the idea of the object by
which it is to be gratified. In this manner, from a series of sensations,
observations, and analyses, a successive train of ideas arises, so linked
together, that an attentive observer may trace back to a certain point the
order and connection of the whole sum of human knowledge.
When we begin the study of any science, we are in a situation, respecting
that science, similar to that of children; and the course by which we have to
advance is precisely the same which Nature follows in the formation of
their ideas. In a child, the idea is merely an effect produced by a sensation;
and, in the same manner, in commencing the study of a physical science, we
ought to form no idea but what is a necessary consequence, and immediate
effect, of an experiment or observation. Besides, he that enters upon the
career of science, is in a less advantageous situation than a child who is
acquiring his first ideas. To the child, Nature gives various means of
rectifying any mistakes he may commit respecting the salutary or hurtful
qualities of the objects which surround him. On every occasion his
judgments are corrected by experience; want and pain are the necessary
consequences arising from false judgment; gratification and pleasure are
produced by judging aright. Under such masters, we cannot fail to become
well informed; and we soon learn to reason justly, when want and pain are
the necessary consequences of a contrary conduct.
In the study and practice of the sciences it is quite different; the false
judgments we form neither affect our existence nor our welfare; and we are
not forced by any physical necessity to correct them. Imagination, on the
contrary, which is ever wandering beyond the bounds of truth, joined to
self-love and that self-confidence we are so apt to indulge, prompt us to

draw conclusions which are not immediately derived from facts; so that we
become in some measure interested in deceiving ourselves. Hence it is by
no means to be wondered, that, in the science of physics in general, men
have often made suppositions, instead of forming conclusions. These
suppositions, handed down from one age to another, acquire additional
weight from the authorities by which they are supported, till at last they are
received, even by men of genius, as fundamental truths.
The only method of preventing such errors from taking place, and of
correcting them when formed, is to restrain and simplify our reasoning as
much as possible. This depends entirely upon ourselves, and the neglect of
it is the only source of our mistakes. We must trust to nothing but facts:
These are presented to us by Nature, and cannot deceive. We ought, in
every instance, to submit our reasoning to the test of experiment, and never
to search for truth but by the natural road of experiment and observation.
Thus mathematicians obtain the solution of a problem by the mere
arrangement of data, and by reducing their reasoning to such simple steps,
to conclusions so very obvious, as never to lose sight of the evidence which
guides them.
Thoroughly convinced of these truths, I have imposed upon myself, as a
law, never to advance but from what is known to what is unknown; never to
form any conclusion which is not an immediate consequence necessarily
flowing from observation and experiment; and always to arrange the facts,
and the conclusions which are drawn from them, in such an order as shall
render it most easy for beginners in the study of chemistry thoroughly to
understand them. Hence I have been obliged to depart from the usual order
of courses of lectures and of treatises upon chemistry, which always assume
the first principles of the science, as known, when the pupil or the reader
should never be supposed to know them till they have been explained in
subsequent lessons. In almost every instance, these begin by treating of the
elements of matter, and by explaining the table of affinities, without
considering, that, in so doing, they must bring the principal phenomena of
chemistry into view at the very outset: They make use of terms which have
not been defined, and suppose the science to be understood by the very
persons they are only beginning to teach. It ought likewise to be considered,
that very little of chemistry can be learned in a first course, which is hardly
sufficient to make the language of the science familiar to the ears, or the

apparatus familiar to the eyes. It is almost impossible to become a chemist
in less than three or four years of constant application.
These inconveniencies are occasioned not so much by the nature of the
subject, as by the method of teaching it; and, to avoid them, I was chiefly
induced to adopt a new arrangement of chemistry, which appeared to me
more consonant to the order of Nature. I acknowledge, however, that in thus
endeavouring to avoid difficulties of one kind, I have found myself
involved in others of a different species, some of which I have not been able
to remove; but I am persuaded, that such as remain do not arise from the
nature of the order I have adopted, but are rather consequences of the
imperfection under which chemistry still labours. This science still has
many chasms, which interrupt the series of facts, and often render it
extremely difficult to reconcile them with each other: It has not, like the
elements of geometry, the advantage of being a complete science, the parts
of which are all closely connected together: Its actual progress, however, is
so rapid, and the facts, under the modern doctrine, have assumed so happy
an arrangement, that we have ground to hope, even in our own times, to see
it approach near to the highest state of perfection of which it is susceptible.
The rigorous law from which I have never deviated, of forming no
conclusions which are not fully warranted by experiment, and of never
supplying the absence of facts, has prevented me from comprehending in
this work the branch of chemistry which treats of affinities, although it is
perhaps the best calculated of any part of chemistry for being reduced into a
completely systematic body. Messrs Geoffroy, Gellert, Bergman, Scheele,
De Morveau, Kirwan, and many others, have collected a number of
particular facts upon this subject, which only wait for a proper arrangement;
but the principal data are still wanting, or, at least, those we have are either
not sufficiently defined, or not sufficiently proved, to become the
foundation upon which to build so very important a branch of chemistry.
This science of affinities, or elective attractions, holds the same place with
regard to the other branches of chemistry, as the higher or transcendental
geometry does with respect to the simpler and elementary part; and I
thought it improper to involve those simple and plain elements, which I
flatter myself the greatest part of my readers will easily understand, in the
obscurities and difficulties which still attend that other very useful and
necessary branch of chemical science.

Perhaps a sentiment of self-love may, without my perceiving it, have given
additional force to these reflections. Mr de Morveau is at present engaged in
publishing the article Affinity in the Methodical Encyclopædia; and I had
more reasons than one to decline entering upon a work in which he is
employed.
It will, no doubt, be a matter of surprise, that in a treatise upon the elements
of chemistry, there should be no chapter on the constituent and elementary
parts of matter; but I shall take occasion, in this place, to remark, that the
fondness for reducing all the bodies in nature to three or four elements,
proceeds from a prejudice which has descended to us from the Greek
Philosophers. The notion of four elements, which, by the variety of their
proportions, compose all the known substances in nature, is a mere
hypothesis, assumed long before the first principles of experimental
philosophy or of chemistry had any existence. In those days, without
possessing facts, they framed systems; while we, who have collected facts,
seem determined to reject them, when they do not agree with our
prejudices. The authority of these fathers of human philosophy still carry
great weight, and there is reason to fear that it will even bear hard upon
generations yet to come.
It is very remarkable, that, notwithstanding of the number of philosophical
chemists who have supported the doctrine of the four elements, there is not
one who has not been led by the evidence of facts to admit a greater number
of elements into their theory. The first chemists that wrote after the revival
of letters, considered sulphur and salt as elementary substances entering
into the composition of a great number of substances; hence, instead of
four, they admitted the existence of six elements. Beccher assumes the
existence of three kinds of earth, from the combination of which, in
different proportions, he supposed all the varieties of metallic substances to
be produced. Stahl gave a new modification to this system; and succeeding
chemists have taken the liberty to make or to imagine changes and additions
of a similar nature. All these chemists were carried along by the influence
of the genius of the age in which they lived, which contented itself with
assertions without proofs; or, at least, often admitted as proofs the slighted
degrees of probability, unsupported by that strictly rigorous analysis
required by modern philosophy.

All that can be said upon the number and nature of elements is, in my
opinion, confined to discussions entirely of a metaphysical nature. The
subject only furnishes us with indefinite problems, which may be solved in
a thousand different ways, not one of which, in all probability, is consistent
with nature. I shall therefore only add upon this subject, that if, by the term
elements, we mean to express those simple and indivisible atoms of which
matter is composed, it is extremely probable we know nothing at all about
them; but, if we apply the term elements, or principles of bodies, to express
our idea of the last point which analysis is capable of reaching, we must
admit, as elements, all the substances into which we are capable, by any
means, to reduce bodies by decomposition. Not that we are entitled to
affirm, that these substances we consider as simple may not be compounded
of two, or even of a greater number of principles; but, since these principles
cannot be separated, or rather since we have not hitherto discovered the
means of separating them, they act with regard to us as simple substances,
and we ought never to suppose them compounded until experiment and
observation has proved them to be so.
The foregoing reflections upon the progress of chemical ideas naturally
apply to the words by which these ideas are to be expressed. Guided by the
work which, in the year 1787, Messrs de Morveau, Berthollet, de Fourcroy,
and I composed upon the Nomenclature of Chemistry, I have endeavoured,
as much as possible, to denominate simple bodies by simple terms, and I
was naturally led to name these first. It will be recollected, that we were
obliged to retain that name of any substance by which it had been long
known in the world, and that in two cases only we took the liberty of
making alterations; first, in the case of those which were but newly
discovered, and had not yet obtained names, or at least which had been
known but for a short time, and the names of which had not yet received the
sanction of the public; and, secondly, when the names which had been
adopted, whether by the ancients or the moderns, appeared to us to express
evidently false ideas, when they confounded the substances, to which they
were applied, with others possessed of different, or perhaps opposite
qualities. We made no scruple, in this case, of substituting other names in
their room, and the greatest number of these were borrowed from the Greek
language. We endeavoured to frame them in such a manner as to express the
most general and the most characteristic quality of the substances; and this

was attended with the additional advantage both of assisting the memory of
beginners, who find it difficult to remember a new word which has no
meaning, and of accustoming them early to admit no word without
connecting with it some determinate idea.
To those bodies which are formed by the union of several simple substances
we gave new names, compounded in such a manner as the nature of the
substances directed; but, as the number of double combinations is already
very considerable, the only method by which we could avoid confusion,
was to divide them into classes. In the natural order of ideas, the name of
the class or genus is that which expresses a quality common to a great
number of individuals: The name of the species, on the contrary, expresses a
quality peculiar to certain individuals only.
These distinctions are not, as some may imagine, merely metaphysical, but
are established by Nature. "A child," says the Abbé de Condillac, "is taught
to give the name tree to the first one which is pointed out to him. The next
one he sees presents the same idea, and he gives it the same name. This he
does likewise to a third and a fourth, till at last the word tree, which he first
applied to an individual, comes to be employed by him as the name of a
class or a genus, an abstract idea, which comprehends all trees in general.
But, when he learns that all trees serve not the same purpose, that they do
not all produce the same kind of fruit, he will soon learn to distinguish them
by specific and particular names." This is the logic of all the sciences, and is
naturally applied to chemistry.
The acids, for example, are compounded of two substances, of the order of
those which we consider as simple; the one constitutes acidity, and is
common to all acids, and, from this substance, the name of the class or the
genus ought to be taken; the other is peculiar to each acid, and distinguishes
it from the rest, and from this substance is to be taken the name of the
species. But, in the greatest number of acids, the two constituent elements,
the acidifying principle, and that which it acidifies, may exist in different
proportions, constituting all the possible points of equilibrium or of
saturation. This is the case in the sulphuric and the sulphurous acids; and
these two states of the same acid we have marked by varying the
termination of the specific name.

Metallic substances which have been exposed to the joint action of the air
and of fire, lose their metallic lustre, increase in weight, and assume an
earthy appearance. In this state, like the acids, they are compounded of a
principle which is common to all, and one which is peculiar to each. In the
same way, therefore, we have thought proper to class them under a generic
name, derived from the common principle; for which purpose, we adopted
the term oxyd; and we distinguish them from each other by the particular
name of the metal to which each belongs.
Combustible substances, which in acids and metallic oxyds are a specific
and particular principle, are capable of becoming, in their turn, common
principles of a great number of substances. The sulphurous combinations
have been long the only known ones in this kind. Now, however, we know,
from the experiments of Messrs Vandermonde, Monge, and Berthollet, that
charcoal may be combined with iron, and perhaps with several other metals;
and that, from this combination, according to the proportions, may be
produced steel, plumbago, &c. We know likewise, from the experiments of
M. Pelletier, that phosphorus may be combined with a great number of
metallic substances. These different combinations we have classed under
generic names taken from the common substance, with a termination which
marks this analogy, specifying them by another name taken from that
substance which is proper to each.
The nomenclature of bodies compounded of three simple substances was
attended with still greater difficulty, not only on account of their number,
but, particularly, because we cannot express the nature of their constituent
principles without employing more compound names. In the bodies which
form this class, such as the neutral salts, for instance, we had to consider,
1st, The acidifying principle, which is common to them all; 2d, The
acidifiable principle which constitutes their peculiar acid; 3d, The saline,
earthy, or metallic basis, which determines the particular species of salt.
Here we derived the name of each class of salts from the name of the
acidifiable principle common to all the individuals of that class; and
distinguished each species by the name of the saline, earthy, or metallic
basis, which is peculiar to it.
A salt, though compounded of the same three principles, may, nevertheless,
by the mere difference of their proportion, be in three different states. The

nomenclature we have adopted would have been defective, had it not
expressed these different states; and this we attained chiefly by changes of
termination uniformly applied to the same state of the different salts.
In short, we have advanced so far, that from the name alone may be
instantly found what the combustible substance is which enters into any
combination; whether that combustible substance be combined with the
acidifying principle, and in what proportion; what is the state of the acid;
with what basis it is united; whether the saturation be exact, or whether the
acid or the basis be in excess.
It may be easily supposed that it was not possible to attain all these different
objects without departing, in some instances, from established custom, and
adopting terms which at first sight will appear uncouth and barbarous. But
we considered that the ear is soon habituated to new words, especially when
they are connected with a general and rational system. The names, besides,
which were formerly employed, such as powder of algaroth, salt of
alembroth, pompholix, phagadenic water, turbith mineral, colcathar, and
many others, were neither less barbarous nor less uncommon. It required a
great deal of practice, and no small degree of memory, to recollect the
substances to which they were applied, much more to recollect the genus of
combination to which they belonged. The names of oil of tartar per
deliquium, oil of vitriol, butter of arsenic and of antimony, flowers of zinc,
&c. were still more improper, because they suggested false ideas: For, in the
whole mineral kingdom, and particularly in the metallic class, there exists
no such thing as butters, oils, or flowers; and, in short, the substances to
which they give these fallacious names, are nothing less than rank poisons.
When we published our essay on the nomenclature of chemistry, we were
reproached for having changed the language which was spoken by our
masters, which they distinguished by their authority, and handed down to
us. But those who reproach us on this account, have forgotten that it was
Bergman and Macquer themselves who urged us to make this reformation.
In a letter which the learned Professor of Upsal, M. Bergman, wrote, a short
time before he died, to M. de Morveau, he bids him spare no improper
names; those who are learned, will always be learned, and those who are
ignorant will thus learn sooner.

There is an objection to the work which I am going to present to the public,
which is perhaps better founded, that I have given no account of the opinion
of those who have gone before me; that I have stated only my own opinion,
without examining that of others. By this I have been prevented from doing
that justice to my associates, and more especially to foreign chemists, which
I wished to render them. But I beseech the reader to consider, that, if I had
filled an elementary work with a multitude of quotations; if I had allowed
myself to enter into long dissertations on the history of the science, and the
works of those who have studied it, I must have lost sight of the true object
I had in view, and produced a work, the reading of which must have been
extremely tiresome to beginners. It is not to the history of the science, or of
the human mind, that we are to attend in an elementary treatise: Our only
aim ought to be ease and perspicuity, and with the utmost care to keep every
thing out of view which might draw aside the attention of the student; it is a
road which we should be continually rendering more smooth, and from
which we should endeavour to remove every obstacle which can occasion
delay. The sciences, from their own nature, present a sufficient number of
difficulties, though we add not those which are foreign to them. But,
besides this, chemists will easily perceive, that, in the first part of my work,
I make very little use of any experiments but those which were made by
myself: If at any time I have adopted, without acknowledgment, the
experiments or the opinions of M. Berthollet, M. Fourcroy, M. de la Place,
M. Monge, or, in general, of any of those whose principles are the same
with my own, it is owing to this circumstance, that frequent intercourse, and
the habit of communicating our ideas, our observations, and our way of
thinking to each other, has established between us a sort of community of
opinions, in which it is often difficult for every one to know his own.
The remarks I have made on the order which I thought myself obliged to
follow in the arrangement of proofs and ideas, are to be applied only to the
first part of this work. It is the only one which contains the general sum of
the doctrine I have adopted, and to which I wished to give a form
completely elementary.
The second part is composed chiefly of tables of the nomenclature of the
neutral salts. To these I have only added general explanations, the object of
which was to point out the most simple processes for obtaining the different
kinds of known acids. This part contains nothing which I can call my own,

and presents only a very short abridgment of the results of these processes,
extracted from the works of different authors.
In the third part, I have given a description, in detail, of all the operations
connected with modern chemistry. I have long thought that a work of this
kind was much wanted, and I am convinced it will not be without use. The
method of performing experiments, and particularly those of modern
chemistry, is not so generally known as it ought to be; and had I, in the
different memoirs which I have presented to the Academy, been more
particular in the detail of the manipulations of my experiments, it is
probable I should have made myself better understood, and the science
might have made a more rapid progress. The order of the different matters
contained in this third part appeared to me to be almost arbitrary; and the
only one I have observed was to class together, in each of the chapters of
which it is composed, those operations which are most connected with one
another. I need hardly mention that this part could not be borrowed from
any other work, and that, in the principal articles it contains, I could not
derive assistance from any thing but the experiments which I have made
myself.
I shall conclude this preface by transcribing, literally, some observations of
the Abbé de Condillac, which I think describe, with a good deal of truth, the
state of chemistry at a period not far distant from our own. These
observations were made on a different subject; but they will not, on this
account, have less force, if the application of them be thought just.
'Instead of applying observation to the things we wished to know, we have
chosen rather to imagine them. Advancing from one ill founded supposition
to another, we have at last bewildered ourselves amidst a multitude of
errors. These errors becoming prejudices, are, of course, adopted as
principles, and we thus bewilder ourselves more and more. The method,
too, by which we conduct our reasonings is as absurd; we abuse words
which we do not understand, and call this the art of reasoning. When
matters have been brought this length, when errors have been thus
accumulated, there is but one remedy by which order can be restored to the
faculty of thinking; this is, to forget all that we have learned, to trace back
our ideas to their source, to follow the train in which they rise, and, as my
Lord Bacon says, to frame the human understanding anew.

'This remedy becomes the more difficult in proportion as we think ourselves
more learned. Might it not be thought that works which treated of the
sciences with the utmost perspicuity, with great precision and order, must be
understood by every body? The fact is, those who have never studied any
thing will understand them better than those who have studied a great deal,
and especially than those who have written a great deal.'
At the end of the fifth chapter, the Abbé de Condillac adds: 'But, after all,
the sciences have made progress, because philosophers have applied
themselves with more attention to observe, and have communicated to their
language that precision and accuracy which they have employed in their
observations: In correcting their language they reason better.'

CONTENTS.
PART FIRST.

Of the Formation and Decomposition of Aëriform Fluids,
—of the Combustion of Simple Bodies, and the Formation of Acids, Page
1

CHAP. I.—Of the Combinations of Caloric, and the Formation of Elastic
Aëriform Fluids or Gasses, ibid.

CHAP. II.—General Views relative to the Formation and Composition of
our Atmosphere, 26

CHAP. III.—Analysis of Atmospheric Air, and its Division into two Elastic
Fluids;
one fit for Respiration, the other incapable of being respired, 32

CHAP. IV.—Nomenclature of the several constituent Parts of Atmospheric
Air, 48

CHAP. V.—Of the Decomposition of Oxygen Gas by Sulphur,
Phosphorus, and Charcoal, and of the Formation of Acids in general, 54

CHAP. VI.—Of the Nomenclature of Acids in general, and particularly of
those drawn from Nitre and Sea Salt, 66

CHAP. VII.—Of the Decomposition of Oxygen Gas
by means of Metals, and the Formation of Metallic Oxyds, 78

CHAP. VIII.—Of the Radical Principle of Water, and of its Decomposition
by Charcoal and Iron, 83

CHAP. IX.—Of the Quantities of Caloric disengaged from different Species

of Combustion, 97

Combustion of Phosphorus, 100

SECT. I.—Combustion of Charcoal, 101

SECT. II.—Combustion of Hydrogen Gas, 102

SECT. III.—Formation of Nitric Acid, 102

SECT. IV.—Combustion of Wax, 105

SECT. V.—Combustion of Olive Oil, 106

CHAP. X.—Of the Combustion of Combustible Substances with each other,
109

CHAP. XI.—Observations upon Oxyds and Acids with several Bases,
and upon the Composition of Animal and Vegetable Substances, 115

CHAP. XII.—Of the Decomposition of Vegetable and Animal Substances
by the Action of Fire, 123

CHAP. XIII.—Of the Decomposition of Vegetable Oxyds by the Vinous
Fermentation, 129

CHAP. XIV.—Of the Putrefactive Fermentation, 141

CHAP. XV.—Of the Acetous Fermentation, 146

CHAP. XVI.—Of the Formation of Neutral Salts, and of their Bases, 149

SECT. I.—Of Potash, 151

SECT. II.—Of Soda, 155

SECT. III.—Of Ammoniac, 156

SECT. IV.—Of Lime, Magnesia, Barytes, and Argill, 157

SECT. V.—Of Metallic Bodies, 159

CHAP. XVII.—Continuation of the Observations upon Salifiable Bases,
and the Formation of Neutral Salts, 161

PART II.

Of the Combinations of Acids with Salifiable Bases, and of the Formation
of Neutral Salts, 175

INTRODUCTION, ibid.

TABLE of Simple Substances, 175

SECT. I.—Observations upon simple Substances, 176

TABLE of Compound Oxydable and Acidifiable Bases, 179

SECT. II.—Observations upon Compound Radicals, 180

SECT. III.—Observations upon the Combinations of Light and Caloric with
different Substances, 182

TABLE of the Combinations of Oxygen with the Simple Substances, to face
185

SECT. IV.—Observations upon these Combinations, 185

TABLE of the Combinations of Oxygen with Compound Radicals, 190

SECT. V.—Observations upon these Combinations, 191

TABLE of the Combinations of Azote with the Simple Substances, 194

SECT VI.—Observations upon these Combinations of Azote, 195

TABLE of the Combinations of Hydrogen with Simple Substances, 198

SECT. VII.—Observations upon Hydrogen, and its Combinations, 199

TABLE of the Binary Combinations of Sulphur with the Simple
Substances, 202

SECT. VIII.—Observations upon Sulphur, and its Combinations, 203

TABLE of the Combinations of Phosphorus with Simple Substances, 204

SECT. IX.—Observations upon Phosphorus and its Combinations, 205

TABLE of the Binary Combinations of Charcoal, 207

SECT. X.—Observations upon Charcoal, and its Combinations, 208

SECT. XI.—Observations upon the Muriatic, Fluoric, and Boracic Radicals,
and their Combinations, 209

SECT. XII.—Observations upon the Combinations of Metals with each
other, 219

TABLE of the Combinations of Azote, in the State of Nitrous Acid, with the
Salifiable Bases, 212

TABLE of the Combinations of Azote, in the State of Nitric Acid, with the
Salifiable Bases, 213

SECT. XIII.—Observations upon Nitrous and Nitric Acids, and their
Combinations with Salifiable Bases, 214

TABLE of the Combinations of Sulphuric Acid with the Salifiable Bases,
218

SECT. XIV.—Observations upon Sulphuric Acid, and its Combinations,
219

TABLE of the Combinations of Sulphurous Acid, 222

SECT. XV.—Observations upon Sulphurous Acid, and its Combinations
with Salifiable Bases, 223

TABLE of the Combinations of Phosphorous and Phosphoric Acids, 225

SECT. XVI.—Observations upon Phosphorous and Phosphoric Acids, and
their Combinations with Salifiable Bases, 226

TABLE of the Combinations of Carbonic Acid, 228

SECT. XVII.—Observations upon Carbonic Acid, and its Combinations
with Salifiable Bases, 229

TABLE of the Combinations of Muriatic Acid, 231

TABLE of the Combinations of Oxygenated Muriatic Acid, 232

SECT. XVIII.—Observations upon Muriatic and Oxygenated Muriatic
Acid,
and their Combinations with Salifiable Bases, 233

TABLE of the Combinations of Nitro-Muriatic Acid, 236

SECT. XIX.—Observations upon Nitro-muriatic Acid, and its
Combinations with Salifiable Bases, 237

TABLE of the Combinations of Fluoric Acid, 239

SECT. XX.—Observations upon Fluoric Acid, and its Combinations with
Salifiable Bases, 240

TABLE of the Combinations of Boracic Acid, 242

SECT. XXI.—Observations upon Boracic Acid, and its Combinations with
Salifiable Bases, 243

TABLE of the Combinations of Arseniac Acid, 246

SECT. XXII.—Observations upon Arseniac Acid, and its Combinations
with Salifiable Bases, 247

SECT. XXIII.—Observations upon Molibdic Acid, and its Combinations
with Salifiable Bases, 249

SECT. XXIV.—Observations upon Tungstic Acid, and its Combinations
with Salifiable Bases,
and a Table of these in the order of their Affinity, 251

TABLE of the Combinations of Tartarous Acid, 253

SECT. XXV.—Observations upon Tartarous Acid, and its Combinations
with Salifiable Bases, 254

SECT. XXVI.—Observations upon Mallic Acid, and its Combinations with
Salifiable Bases, 256

TABLE of the Combinations of Citric Acid, 258

SECT. XXVII.—Observations upon Citric Acid, and its Combinations with
Salifiable Bases, 259

TABLE of the Combinations of Pyro-lignous Acid, 260

SECT. XXVIII.—Observations upon Pyro-lignous Acid, and its
Combinations with Salifiable Bases, 261

SECT. XXIX.—Observations upon Pyro-tartarous Acid, and its
Combinations with Salifiable Bases, ibid.

TABLE of the Combinations of Pyro-mucous Acid, 263

SECT. XXX.—Observations upon Pyro-mucous Acid, and its
Combinations with Salifiable Bases, 264

TABLE of the Combinations of Oxalic Acid, 265

SECT. XXXI.—Observations upon Oxalic Acid, and its Combinations with
Salifiable Bases, 266

TABLE of the Combinations of Acetous Acid, to face 267

SECT. XXXII.—Observations upon Acetous Acid, and its Combinations
with the Salifiable Bases, 267

TABLE of the Combinations of Acetic Acid, 271

SECT. XXXIII.—Observations upon Acetic Acid, and its Combinations
with Salifiable Bases, 272

TABLE of the Combinations of Succinic Acid, 273

SECT. XXXIV.—Observations upon Succinic Acid, and its Combinations
with Salifiable Bases, 274

SECT. XXXV.—Observations upon Benzoic Acid, and its Combinations
with Salifiable Bases, 275

SECT. XXXVI.—Observations upon Camphoric Acid, and its
Combinations with Salifiable Bases, 276

SECT. XXXVII.—Observations upon Gallic Acid, and its Combinations
with Salifiable Bases, 277

SECT. XXXVIII.—Observations upon Lactic Acid, and its Combinations
with Salifiable Bases, 278

TABLE of the Combinations of Saccholactic Acid, 280

SECT. XXXIX.—Observations upon Saccholactic Acid, and its
Combination with Salifiable Bases, 281

TABLE of the Combinations of Formic Acid, 282

SECT. XL.—Observations upon Formic Acid, and its Combinations with
the Salifiable Bases, 283

SECT. XLI.—Observations upon the Bombic Acid, and its Combinations
with the Salifiable Bases, 284

TABLE of the Combinations of the Sebacic Acid, 285

SECT. XLII.—Observations upon the Sebacic Acid, and its Combinations
with the Salifiable Bases, 286

SECT. XLIII.—Observations upon the Lithic Acid, and its Combinations
with the Salifiable Bases, 287

TABLE of the Combinations of the Prussic Acid, 288

SECT. XLIV.—Observations upon the Prussic Acid, and its Combinations
with the Salifiable Bases, 289

PART III.

Description of the Instruments and Operations of Chemistry, 291

INTRODUCTION, 291

CHAP. I.—Of the Instruments necessary for determining
the Absolute and Specific Gravities of Solid and Liquid Bodies, 295

CHAP. II.—Of Gazometry, or the Measurement of the Weight and Volume
of Aëriform Substances, 304

SECT. I.—Of the Pneumato-chemical Apparatus, ibid.

SECT. II.—Of the Gazometer, 308

SECT. III.—Some other methods for Measuring the Volume of Gasses, 319

SECT. IV.—Of the method of Separating the different Gasses from each
other, 323

SECT. V.—Of the necessary Corrections of the Volume of Gasses,
according to the Pressure of the Atmosphere, 328

SECT. VI.—Of the Correction relative to the Degrees of the Thermometer,
335

SECT. VII.—Example for Calculating the Corrections
relative to the Variations of Pressure and Temperature, 337

SECT. VIII.—Method of determining the Weight of the different Gasses,
340

CHAP. III.—Description of the Calorimeter, or Apparatus for measuring
Caloric, 343

CHAP. IV.—Of the Mechanical Operations for Division of Bodies, 357

SECT. I.—Of Trituration, Levigation, and Pulverization, ibid.

SECT. II.—Of Sifting and Washing Powdered Substances, 361

SECT. III.—Of Filtration, 363

SECT. IV.—Of Decantation, 365

CHAP. V.—Of Chemical means for Separating the Particles of Bodies
from each other without Decomposition, and for Uniting them again,
367

SECT. I.—Of the Solution of Salts, 368

SECT. II.—Of Lixiviation, 373

SECT. III.—Of Evaporation, 375

SECT. IV.—Of Cristallization, 379

SECT. V.—Of Simple Distillation, 384

SECT. VI.—Of Sublimation, 388

CHAP. VI.—Of Pneumato-chemical Distillations, Metallic Dissolutions,
and some other operations which require very complicated instruments,
390

SECT. I.—Of Compound and Pneumato-chemical Distillations, ibid.

SECT. II.—Of Metallic Dissolutions, 398

SECT. III.—Apparatus necessary in Experiments upon Vinous and
Putrefactive Fermentations, 401

SECT. IV.—Apparatus for the Decomposition of Water, 404

CHAP. VII.—Of the Composition and Use of Lutes, 407

CHAP. VIII.—Of Operations upon Combustion and Deflagration, 414

SECT. I.—Of Combustion in general, ibid.

SECT. II.—Of the Combustion of Phosphorus, 418

SECT. III.—Of the Combustion of Charcoal, 422

SECT. IV.—Of the Combustion of Oils, 426

SECT. V.—Of the Combustion of Alkohol, 433

SECT. VI.—Of the Combustion of Ether, 435

SECT. VII.—Of the Combustion of Hydrogen Gas, and the Formation of
Water, 437

SECT. VIII.—Of the Oxydation of Metals, 441

CHAP. IX.—Of Deflagration, 452

CHAP. X.—Of the Instruments necessary for Operating upon Bodies in
very high Temperatures, 460

SECT. I.—Of Fusion, ibid.

SECT. II.—Of Furnaces, 462

SECT. III.—Of increasing the Action of Fire, by using Oxygen Gas instead
of Atmospheric Air, 474

APPENDIX.

No. I.—Table for Converting Lines, or Twelfth Parts of an Inch,
and Fractions of Lines, into Decimal Fractions of the Inch, 481

No. II.—Table for Converting the Observed Heighth of Water in the Jars of
the Pneumato-Chemical
Apparatus, expressed in Inches and Decimals, into Corresponding
Heighths of Mercury, 482

No. III.—Table for Converting the Ounce Measures used

by Dr Priestley into French and English Cubical Inches, 483

No. IV.—Table for Reducing the Degrees of
Reaumeur's Thermometer into its corresponding Degrees of Fahrenheit's
Scale, 484

No. V.—Additional.—Rules for Converting French Weights
and Measures into correspondent English Denominations, 485

No. VI.—Table of the Weights of the different Gasses, at 28 French inches,
or 29.84 English inches barometrical pressure, and at 10° (54.5°) of
temperature,
expressed in English measure and English Troy weight, 490

No. VII.—Tables of the Specific Gravities of different bodies, 491

No. VIII.—Additional.—Rules for Calculating the Absolute Gravity in
English Troy Weight of a
Cubic Foot and Inch, English Measure, of any Substance whose Specific
Gravity is known, 505

No. IX.—Tables for Converting Ounces, Drams, and Grains, Troy, into
Decimals of the Troy Pound of 12 Ounces, and for Converting Decimals
of the Pound Troy
into Ounces, &c. 508

No. X.—Table of the English Cubical Inches and Decimals corresponding
to a determinate Troy
Weight of Distilled Water at the Temperature of 55°, calculated from
Everard's experiment, 511

ELEMENTS
OF

CHEMISTRY.

PART I.
Of the Formation and Decomposition of Aëriform Fluids—of
the Combustion of Simple Bodies—and the Formation of Acids.

CHAP. I.
Of the Combinations of Caloric, and the Formation of Elastic
Aëriform Fluids.

That every body, whether solid or fluid, is augmented in all its dimensions
by any increase of its sensible heat, was long ago fully established as a
physical axiom, or universal proposition, by the celebrated Boerhaave. Such
facts as have been adduced for controverting the generality of this principle
offer only fallacious results, or, at least, such as are so complicated with
foreign circumstances as to mislead the judgment: But, when we separately
consider the effects, so as to deduce each from the cause to which they
separately belong, it is easy to perceive that the separation of particles by
heat is a constant and general law of nature.
When we have heated a solid body to a certain degree, and have thereby
caused its particles to separate from each other, if we allow the body to
cool, its particles again approach each other in the same proportion in which
they were separated by the increased temperature; the body returns through
the same degrees of expansion which it before extended through; and, if it
be brought back to the same temperature from which we set out at the
commencement of the experiment, it recovers exactly the same dimensions
which it formerly occupied. But, as we are still very far from being able to
arrive at the degree of absolute cold, or deprivation of all heat, being
unacquainted with any degree of coldness which we cannot suppose
capable of still farther augmentation, it follows, that we are still incapable
of causing the ultimate particles of bodies to approach each other as near as
is possible; and, consequently, that the particles of all bodies do not touch
each other in any state hitherto known, which, tho' a very singular
conclusion, is yet impossible to be denied.
It is supposed, that, since the particles of bodies are thus continually
impelled by heat to separate from each other, they would have no
connection between themselves; and, of consequence, that there could be no
solidity in nature, unless they were held together by some other power

which tends to unite them, and, so to speak, to chain them together; which
power, whatever be its cause, or manner of operation, we name Attraction.
Thus the particles of all bodies may be considered as subjected to the action
of two opposite powers, the one repulsive, the other attractive, between
which they remain in equilibrio. So long as the attractive force remains
stronger, the body must continue in a state of solidity; but if, on the
contrary, heat has so far removed these particles from each other, as to place
them beyond the sphere of attraction, they lose the adhesion they before had
with each other, and the body ceases to be solid.
Water gives us a regular and constant example of these facts; whilst below
Zero[2] of the French thermometer, or 32° of Fahrenheit, it remains solid,
and is called ice. Above that degree of temperature, its particles being no
longer held together by reciprocal attraction, it becomes liquid; and, when
we raise its temperature above 80°, (212°) its particles, giving way to the
repulsion caused by the heat, assume the state of vapour or gas, and the
water is changed into an aëriform fluid.
The same may be affirmed of all bodies in nature: They are either solid or
liquid, or in the state of elastic aëriform vapour, according to the proportion
which takes place between the attractive force inherent in their particles,
and the repulsive power of the heat acting upon these; or, what amounts to
the same thing, in proportion to the degree of heat to which they are
exposed.
It is difficult to comprehend these phenomena, without admitting them as
the effects of a real and material substance, or very subtile fluid, which,
insinuating itself between the particles of bodies, separates them from each
other; and, even allowing the existence of this fluid to be hypothetical, we
shall see in the sequel, that it explains the phenomena of nature in a very
satisfactory manner.
This substance, whatever it is, being the cause of heat, or, in other words,
the sensation which we call warmth being caused by the accumulation of
this substance, we cannot, in strict language, distinguish it by the term heat;
because the same name would then very improperly express both cause and
effect. For this reason, in the memoir which I published in 1777[3], I gave it
the names of igneous fluid and matter of heat. And, since that time, in the

work[4] published by Mr de Morveau, Mr Berthollet, Mr de Fourcroy, and
myself, upon the reformation of chemical nomenclature, we thought it
necessary to banish all periphrastic expressions, which both lengthen
physical language, and render it more tedious and less distinct, and which
even frequently does not convey sufficiently just ideas of the subject
intended. Wherefore, we have distinguished the cause of heat, or that
exquisitely elastic fluid which produces it, by the term of caloric. Besides,
that this expression fulfils our object in the system which we have adopted,
it possesses this farther advantage, that it accords with every species of
opinion, since, strictly speaking, we are not obliged to suppose this to be a
real substance; it being sufficient, as will more clearly appear in the sequel
of this work, that it be considered as the repulsive cause, whatever that may
be, which separates the particles of matter from each other; so that we are
still at liberty to investigate its effects in an abstract and mathematical
manner.
In the present state of our knowledge, we are unable to determine whether
light be a modification of caloric, or if caloric be, on the contrary, a
modification of light. This, however, is indisputable, that, in a system where
only decided facts are admissible, and where we avoid, as far as possible, to
suppose any thing to be that is not really known to exist, we ought
provisionally to distinguish, by distinct terms, such things as are known to
produce different effects. We therefore distinguish light from caloric;
though we do not therefore deny that these have certain qualities in
common, and that, in certain circumstances, they combine with other bodies
almost in the same manner, and produce, in part, the same effects.
What I have already said may suffice to determine the idea affixed to the
word caloric; but there remains a more difficult attempt, which is, to give a
just conception of the manner in which caloric acts upon other bodies. Since
this subtile matter penetrates through the pores of all known substances;
since there are no vessels through which it cannot escape, and,
consequently, as there are none which are capable of retaining it, we can
only come at the knowledge of its properties by effects which are fleeting,
and difficultly ascertainable. It is in these things which we neither see nor
feel, that it is especially necessary to guard against the extravagancy of our
imagination, which forever inclines to step beyond the bounds of truth, and
is very difficultly restrained within the narrow line of facts.

We have already seen, that the same body becomes solid, or fluid, or
aëriform, according to the quantity of caloric by which it is penetrated; or,
to speak more strictly, according as the repulsive force exerted by the
caloric is equal to, stronger, or weaker, than the attraction of the particles of
the body it acts upon.
But, if these two powers only existed, bodies would become liquid at an
indivisible degree of the thermometer, and would almost instantaneously
pass from the solid state of aggregation to that of aëriform elasticity. Thus
water, for instance, at the very moment when it ceases to be ice, would
begin to boil, and would be transformed into an aëriform fluid, having its
particles scattered indefinitely through the surrounding space. That this does
not happen, must depend upon the action of some third power. The pressure
of the atmosphere prevents this separation, and causes the water to remain
in the liquid state till it be raised to 80° of temperature (212°) above zero of
the French thermometer, the quantity of caloric which it receives in the
lowest temperature being insufficient to overcome the pressure of the
atmosphere.
Whence it appears that, without this atmospheric pressure, we should not
have any permanent liquid, and should only be able to see bodies in that
state of existence in the very instant of melting, as the smallest additional
caloric would instantly separate their particles, and dissipate them through
the surrounding medium. Besides, without this atmospheric pressure, we
should not even have any aëriform fluids, strictly speaking, because the
moment the force of attraction is overcome by the repulsive power of the
caloric, the particles would separate themselves indefinitely, having nothing
to give limits to their expansion, unless their own gravity might collect
them together, so as to form an atmosphere.
Simple reflection upon the most common experiments is sufficient to evince
the truth of these positions. They are more particularly proved by the
following experiment, which I published in the Memoirs of the French
Academy for 1777, p. 426.

Having filled with sulphuric ether[5] a small narrow glass vessel, A, (Plate
VII. Fig. 17.), standing upon its stalk P, the vessel, which is from twelve to
fifteen lines diameter, is to be covered by a wet bladder, tied round its neck

with several turns of strong thread; for greater security, fix a second bladder
over the first. The vessel should be filled in such a manner with the ether, as
not to leave the smallest portion of air between the liquor and the bladder. It
is now to be placed under the recipient BCD of an air-pump, of which the
upper part B ought to be fitted with a leathern lid, through which passes a
wire EF, having its point F very sharp; and in the same receiver there ought
to be placed the barometer GH. The whole being thus disposed, let the
recipient be exhausted, and then, by pushing down the wire EF, we make a
hole in the bladder. Immediately the ether begins to boil with great
violence, and is changed into an elastic aëriform fluid, which fills the
receiver. If the quantity of ether be sufficient to leave a few drops in the
phial after the evaporation is finished, the elastic fluid produced will sustain
the mercury in the barometer attached to the air-pump, at eight or ten inches
in winter, and from twenty to twenty-five in summer[6]. To render this
experiment more complete, we may introduce a small thermometer into the
phial A, containing the ether, which will descend considerably during the
evaporation.
The only effect produced in this experiment is, the taking away the weight
of the atmosphere, which, in its ordinary state, presses on the surface of the
ether; and the effects resulting from this removal evidently prove, that, in
the ordinary temperature of the earth, ether would always exist in an
aëriform state, but for the pressure of the atmosphere, and that the passing
of the ether from the liquid to the aëriform state is accompanied by a
considerable lessening of heat; because, during the evaporation, a part of
the caloric, which was before in a free state, or at least in equilibrio in the
surrounding bodies, combines with the ether, and causes it to assume the
aëriform state.
The same experiment succeeds with all evaporable fluids, such as alkohol,
water, and even mercury; with this difference, that the atmosphere formed
in the receiver by alkohol only supports the attached barometer about one
inch in winter, and about four or five inches in summer; that formed by
water, in the same situation, raises the mercury only a few lines, and that by
quicksilver but a few fractions of a line. There is therefore less fluid
evaporated from alkohol than from ether, less from water than from alkohol,
and still less from mercury than from either; consequently there is less

caloric employed, and less cold produced, which quadrates exactly with the
results of these experiments.
Another species of experiment proves very evidently that the aëriform state
is a modification of bodies dependent on the degree of temperature, and on
the pressure which these bodies undergo. In a Memoir read by Mr de la
Place and me to the Academy in 1777, which has not been printed, we have
shown, that, when ether is subjected to a pressure equal to twenty-eight
inches of the barometer, or about the medium pressure of the atmosphere, it
boils at the temperature of about 32° (104°), or 33° (106.25°), of the
thermometer. Mr de Luc, who has made similar experiments with spirit of
wine, finds it boils at 67° (182.75°). And all the world knows that water
boils at 80° (212°). Now, boiling being only the evaporation of a liquid, or
the moment of its passing from the fluid to the aëriform state, it is evident
that, if we keep ether continually at the temperature of 33° (106.25°), and
under the common pressure of the atmosphere, we shall have it always in an
elastic aëriform state; and that the same thing will happen with alkohol
when above 67° (182.75°), and with water when above 80° (212°); all
which are perfectly conformable to the following experiment[7].
I filled a large vessel ABCD (Plate VII. Fig. 16.) with water, at 35°
(110.75°), or 36° (113°); I suppose the vessel transparent, that we may see
what takes place in the experiment; and we can easily hold the hands in
water at that temperature without inconvenience. Into it I plunged some
narrow necked bottles F, G, which were filled with the water, after which
they were turned up, so as to rest on their mouths on the bottom of the
vessel. Having next put some ether into a very small matrass, with its neck
a b c, twice bent as in the Plate, I plunged this matrass into the water, so as
to have its neck inserted into the mouth of one of the bottles F. Immediately
upon feeling the effects of the heat communicated to it by the water in the
vessel ABCD it began to boil; and the caloric entering into combination
with it, changed it into elastic aëriform fluid, with which I filled several
bottles successively, F, G, &c.
This is not the place to enter upon the examination of the nature and
properties of this aëriform fluid, which is extremely inflammable; but,
confining myself to the object at present in view, without anticipating
circumstances, which I am not to suppose the reader to know, I shall only

observe, that the ether, from this experiment, is almost only capable of
existing in the aëriform state in our world; for, if the weight of our
atmosphere was only equal to between 20 and 24 inches of the barometer,
instead of 28 inches, we should never be able to obtain ether in the liquid
state, at least in summer; and the formation of ether would consequently be
impossible upon mountains of a moderate degree of elevation, as it would
be converted into gas immediately upon being produced, unless we
employed recipients of extraordinary strength, together with refrigeration
and compression. And, lastly, the temperature of the blood being nearly that
at which ether passes from the liquid to the aëriform state, it must evaporate
in the primae viae, and consequently it is very probable the medical
properties of this fluid depend chiefly upon its mechanical effect.
These experiments succeed better with nitrous ether, because it evaporates
in a lower temperature than sulphuric ether. It is more difficult to obtain
alkohol in the aëriform state; because, as it requires 67° (182.75°) to reduce
it to vapour, the water of the bath must be almost boiling, and consequently
it is impossible to plunge the hands into it at that temperature.
It is evident that, if water were used in the foregoing experiment, it would
be changed into gas, when exposed to a temperature superior to that at
which it boils. Although thoroughly convinced of this, Mr de la Place and
myself judged it necessary to confirm it by the following direct experiment.
We filled a glass jar A, (Plate VII. Fig. 5.) with mercury, and placed it with
its mouth downwards in a dish B, likewise filled with mercury, and having
introduced about two gross of water into the jar, which rose to the top of the
mercury at CD; we then plunged the whole apparatus into an iron boiler
EFGH, full of boiling sea-water of the temperature of 85° (123.25°), placed
upon the furnace GHIK. Immediately upon the water over the mercury
attaining the temperature of 80° (212°), it began to boil; and, instead of only
filling the small space ACD, it was converted into an aëriform fluid, which
filled the whole jar; the mercury even descended below the surface of that
in the dish B; and the jar must have been overturned, if it had not been very
thick and heavy, and fixed to the dish by means of iron-wire. Immediately
after withdrawing the apparatus from the boiler, the vapour in the jar began
to condense, and the mercury rose to its former station; but it returned again
to the aëriform state a few seconds after replacing the apparatus in the
boiler.

We have thus a certain number of substances, which are convertible into
elastic aëriform fluids by degrees of temperature, not much superior to that
of our atmosphere. We shall afterwards find that there are several others
which undergo the same change in similar circumstances, such as muriatic
or marine acid, ammoniac or volatile alkali, the carbonic acid or fixed air,
the sulphurous acid, &c. All of these are permanently elastic in or about the
mean temperature of the atmosphere, and under its common pressure.
All these facts, which could be easily multiplied if necessary, give me full
right to assume, as a general principle, that almost every body in nature is
susceptible of three several states of existence, solid, liquid, and aëriform,
and that these three states of existence depend upon the quantity of caloric
combined with the body. Henceforwards I shall express these elastic
aëriform fluids by the generic term gas; and in each species of gas I shall
distinguish between the caloric, which in some measure serves the purpose
of a solvent, and the substance, which in combination with the caloric,
forms the base of the gas.
To these bases of the different gases, which are hitherto but little known, we
have been obliged to assign names; these I shall point out in Chap. IV. of
this work, when I have previously given an account of the phenomena
attendant upon the heating and cooling of bodies, and when I have
established precise ideas concerning the composition of our atmosphere.
We have already shown, that the particles of every substance in nature exist
in a certain state of equilibrium, between that attraction which tends to unite
and keep the particles together, and the effects of the caloric which tends to
separate them. Hence the caloric not only surrounds the particles of all
bodies on every side, but fills up every interval which the particles of
bodies leave between each other. We may form an idea of this, by supposing
a vessel filled with small spherical leaden bullets, into which a quantity of
fine sand is poured, which, insinuating into the intervals between the
bullets, will fill up every void. The balls, in this comparison, are to the sand
which surrounds them exactly in the same situation as the particles of
bodies are with respect to the caloric; with this difference only, that the balls
are supposed to touch each other, whereas the particles of bodies are not in
contact, being retained at a small distance from each other, by the caloric.

If, instead of spherical balls, we substitute solid bodies of a hexahedral,
octohedral, or any other regular figure, the capacity of the intervals between
them will be lessened, and consequently will no longer contain the same
quantity of sand. The same thing takes place, with respect to natural bodies;
the intervals left between their particles are not of equal capacity, but vary
in consequence of the different figures and magnitude of their particles, and
of the distance at which these particles are maintained, according to the
existing proportion between their inherent attraction, and the repulsive force
exerted upon them by the caloric.
In this manner we must understand the following expression, introduced by
the English philosophers, who have given us the first precise ideas upon this
subject; the capacity of bodies for containing the matter of heat. As
comparisons with sensible objects are of great use in assisting us to form
distinct notions of abstract ideas, we shall endeavour to illustrate this, by
instancing the phenomena which take place between water and bodies
which are wetted and penetrated by it, with a few reflections.
If we immerge equal pieces of different kinds of wood, suppose cubes of
one foot each, into water, the fluid gradually insinuates itself into their
pores, and the pieces of wood are augmented both in weight and magnitude:
But each species of wood will imbibe a different quantity of water; the
lighter and more porous woods will admit a larger, the compact and closer
grained will admit of a lesser quantity; for the proportional quantities of
water imbibed by the pieces will depend upon the nature of the constituent
particles of the wood, and upon the greater or lesser affinity subsisting
between them and water. Very resinous wood, for instance, though it may
be at the same time very porous, will admit but little water. We may
therefore say, that the different kinds of wood possess different capacities
for receiving water; we may even determine, by means of the augmentation
of their weights, what quantity of water they have actually absorbed; but, as
we are ignorant how much water they contained, previous to immersion, we
cannot determine the absolute quantity they contain, after being taken out of
the water.
The same circumstances undoubtedly take place, with bodies that are
immersed in caloric; taking into consideration, however, that water is an
incompressible fluid, whereas caloric is, on the contrary, endowed with very

great elasticity; or, in other words, the particles of caloric have a great
tendency to separate from each other, when forced by any other power to
approach; this difference must of necessity occasion very considerable
diversities in the results of experiments made upon these two substances.
Having established these clear and simple propositions, it will be very easy
to explain the ideas which ought to be affixed to the following expressions,
which are by no means synonimous, but possess each a strict and
determinate meaning, as in the following definitions:
Free caloric, is that which is not combined in any manner with any other
body. But, as we live in a system to which caloric has a very strong
adhesion, it follows that we are never able to obtain it in the state of
absolute freedom.
Combined caloric, is that which is fixed in bodies by affinity or elective
attraction, so as to form part of the substance of the body, even part of its
solidity.
By the expression specific caloric of bodies, we understand the respective
quantities of caloric requisite for raising a number of bodies of the same
weight to an equal degree of temperature. This proportional quantity of
caloric depends upon the distance between the constituent particles of
bodies, and their greater or lesser degrees of cohesion; and this distance, or
rather the space or void resulting from it, is, as I have already observed,
called the capacity of bodies for containing caloric.
Heat, considered as a sensation, or, in other words, sensible heat, is only the
effect produced upon our sentient organs, by the motion or passage of
caloric, disengaged from the surrounding bodies. In general, we receive
impressions only in consequence of motion, and we might establish it as an
axiom, That, without motion, there is no sensation. This general principle
applies very accurately to the sensations of heat and cold: When we touch a
cold body, the caloric which always tends to become in equilibrio in all
bodies, passes from our hand into the body we touch, which gives us the
feeling or sensation of cold. The direct contrary happens, when we touch a
warm body, the caloric then passing from the body into our hand, produces
the sensation of heat. If the hand and the body touched be of the same
temperature, or very nearly so, we receive no impression, either of heat or

cold, because there is no motion or passage of caloric; and thus no sensation
can take place, without some correspondent motion to occasion it.
When the thermometer rises, it shows, that free caloric is entering into the
surrounding bodies: The thermometer, which is one of these, receives its
share in proportion to its mass, and to the capacity which it possesses for
containing caloric. The change therefore which takes place upon the
thermometer, only announces a change of place of the caloric in those
bodies, of which the thermometer forms one part; it only indicates the
portion of caloric received, without being a measure of the whole quantity
disengaged, displaced, or absorbed.
The most simple and most exact method for determining this latter point, is
that described by Mr de la Place, in the Memoirs of the Academy, No. 1780,
p. 364; a summary explanation of which will be found towards the
conclusion of this work. This method consists in placing a body, or a
combination of bodies, from which caloric is disengaging, in the midst of a
hollow sphere of ice; and the quantity of ice melted becomes an exact
measure of the quantity of caloric disengaged. It is possible, by means of
the apparatus which we have caused to be constructed upon this plan, to
determine, not as has been pretended, the capacity of bodies for containing
heat, but the ratio of the increase or diminution of capacity produced by
determinate degrees of temperature. It is easy with the same apparatus, by
means of divers combinations of experiments, to determine the quantity of
caloric requisite for converting solid substances into liquids, and liquids
into elastic aëriform fluids; and, vice versa, what quantity of caloric escapes
from elastic vapours in changing to liquids, and what quantity escapes from
liquids during their conversion into solids. Perhaps, when experiments have
been made with sufficient accuracy, we may one day be able to determine
the proportional quantity of caloric, necessary for producing the several
species of gasses. I shall hereafter, in a separate chapter, give an account of
the principal results of such experiments as have been made upon this head.
It remains, before finishing this article, to say a few words relative to the
cause of the elasticity of gasses, and of fluids in the state of vapour. It is by
no means difficult to perceive that this elasticity depends upon that of
caloric, which seems to be the most eminently elastic body in nature.
Nothing is more readily conceived, than that one body should become

elastic by entering into combination with another body possessed of that
quality. We must allow that this is only an explanation of elasticity, by an
assumption of elasticity, and that we thus only remove the difficulty one
step farther, and that the nature of elasticity, and the reason for caloric being
elastic, remains still unexplained. Elasticity in the abstract is nothing more
than that quality of the particles of bodies by which they recede from each
other when forced together. This tendency in the particles of caloric to
separate, takes place even at considerable distances. We shall be satisfied of
this, when we consider that air is susceptible of undergoing great
compression, which supposes that its particles were previously very distant
from each other; for the power of approaching together certainly supposes a
previous distance, at least equal to the degree of approach. Consequently,
those particles of the air, which are already considerably distant from each
other, tend to separate still farther. In fact, if we produce Boyle's vacuum in
a large receiver, the very last portion of air which remains spreads itself
uniformly through the whole capacity of the vessel, however large, fills it
completely throughout, and presses every where against its sides: We
cannot, however, explain this effect, without supposing that the particles
make an effort to separate themselves on every side, and we are quite
ignorant at what distance, or what degree of rarefaction, this effort ceases to
act.
Here, therefore, exists a true repulsion between the particles of elastic
fluids; at least, circumstances take place exactly as if such a repulsion
actually existed; and we have very good right to conclude, that the particles
of caloric mutually repel each other. When we are once permitted to
suppose this repelling force, the rationale of the formation of gasses, or
aëriform fluids, becomes perfectly simple; tho' we must, at the same time,
allow, that it is extremely difficult to form an accurate conception of this
repulsive force acting upon very minute particles placed at great distances
from each other.
It is, perhaps, more natural to suppose, that the particles of caloric have a
stronger mutual attraction than those of any other substance, and that these
latter particles are forced asunder in consequence of this superior attraction
between the particles of the caloric, which forces them between the
particles of other bodies, that they may be able to reunite with each other.
We have somewhat analogous to this idea in the phenomena which occur

when a dry sponge is dipt into water: The sponge swells; its particles
separate from each other; and all its intervals are filled up by the water. It is
evident, that the sponge, in the act of swelling, has acquired a greater
capacity for containing water than it had when dry. But we cannot certainly
maintain, that the introduction of water between the particles of the sponge
has endowed them with a repulsive power, which tends to separate them
from each other; on the contrary, the whole phenomena are produced by
means of attractive powers; and these are, first, The gravity of the water,
and the power which it exerts on every side, in common with all other
fluids; 2dly, The force of attraction which takes place between the particles
of the water, causing them to unite together; 3dly, The mutual attraction of
the particles of the sponge with each other; and, lastly, The reciprocal
attraction which exists between the particles of the sponge and those of the
water. It is easy to understand, that the explanation of this fact depends
upon properly appreciating the intensity of, and connection between, these
several powers. It is probable, that the separation of the particles of bodies,
occasioned by caloric, depends in a similar manner upon a certain
combination of different attractive powers, which, in conformity with the
imperfection of our knowledge, we endeavour to express by saying, that
caloric communicates a power of repulsion to the particles of bodies.

FOOTNOTES:
[2] Whenever the degree of heat occurs in this work, it is stated by the author
according to Reaumur's scale. The degrees within brackets are the correspondent
degrees of Fahrenheit's scale, added by the translator. E.
[3] Collections of the French Academy of Sciences for that year, p. 420.
[4] Chemical Nomenclature.
[5] As I shall afterwards give a definition, and explain the properties of the
liquor called ether, I shall only premise here, that it is a very volatile
inflammable liquor, having a considerably smaller specific gravity than water, or
even spirit of wine.—A.
[6] It would have been more satisfactory if the Author had specified the degrees
of the thermometer at which these heights of the mercury in the barometer are
produced.
[7] Vide Memoirs of the French Academy, anno 1780, p. 335.—A.

CHAP. II.
General Views relative to the Formation and Composition of our
Atmosphere.

These views which I have taken of the formation of elastic aëriform fluids
or gasses, throw great light upon the original formation of the atmospheres
of the planets, and particularly that of our earth. We readily conceive, that it
must necessarily consist of a mixture of the following substances: First, Of
all bodies that are susceptible of evaporation, or, more strictly speaking,
which are capable of retaining the state of aëriform elasticity in the
temperature of our atmosphere, and under a pressure equal to that of a
column of twenty-eight inches of quicksilver in the barometer; and,
secondly, Of all substances, whether liquid or solid, which are capable of
being dissolved by this mixture of different gasses.
The better to determine our ideas relating to this subject, which has not
hitherto been sufficiently considered, let us, for a moment, conceive what
change would take place in the various substances which compose our
earth, if its temperature were suddenly altered. If, for instance, we were
suddenly transported into the region of the planet Mercury, where probably
the common temperature is much superior to that of boiling water, the water
of the earth, and all the other fluids which are susceptible of the gasseous
state, at a temperature near to that of boiling water, even quicksilver itself,
would become rarified; and all these substances would be changed into
permanent aëriform fluids or gasses, which would become part of the new
atmosphere. These new species of airs or gasses would mix with those
already existing, and certain reciprocal decompositions and new
combinations would take place, until such time as all the elective attractions
or affinities subsisting amongst all these new and old gasseous substances
had operated fully; after which, the elementary principles composing these
gasses, being saturated, would remain at rest. We must attend to this,
however, that, even in the above hypothetical situation, certain bounds
would occur to the evaporation of these substances, produced by that very

evaporation itself; for as, in proportion to the increase of elastic fluids, the
pressure of the atmosphere would be augmented, as every degree of
pressure tends, in some measure, to prevent evaporation, and as even the
most evaporable fluids can resist the operation of a very high temperature
without evaporating, if prevented by a proportionally stronger compression,
water and all other liquids being able to sustain a red heat in Papin's
digester; we must admit, that the new atmosphere would at last arrive at
such a degree of weight, that the water which had not hitherto evaporated
would cease to boil, and, of consequence, would remain liquid; so that,
even upon this supposition, as in all others of the same nature, the
increasing gravity of the atmosphere would find certain limits which it
could not exceed. We might even extend these reflections greatly farther,
and examine what change might be produced in such situations upon
stones, salts, and the greater part of the fusible substances which compose
the mass of our earth. These would be softened, fused, and changed into
fluids, &c.: But these speculations carry me from my object, to which I
hasten to return.
By a contrary supposition to the one we have been forming, if the earth
were suddenly transported into a very cold region, the water which at
present composes our seas, rivers, and springs, and probably the greater
number of the fluids we are acquainted with, would be converted into solid
mountains and hard rocks, at first diaphanous and homogeneous, like rock
crystal, but which, in time, becoming mixed with foreign and heterogeneous
substances, would become opake stones of various colours. In this case, the
air, or at least some part of the aëriform fluids which now compose the mass
of our atmosphere, would doubtless lose its elasticity for want of a
sufficient temperature to retain them in that state: They would return to the
liquid state of existence, and new liquids would be formed, of whose
properties we cannot, at present, form the most distant idea.
These two opposite suppositions give a distinct proof of the following
corollaries: First, That solidity, liquidity, and aëriform elasticity, are only
three different states of existence of the same matter, or three particular
modifications which almost all substances are susceptible of assuming
successively, and which solely depend upon the degree of temperature to
which they are exposed; or, in other words, upon the quantity of caloric
with which they are penetrated[8]. 2dly, That it is extremely probable that air

is a fluid naturally existing in a state of vapour; or, as we may better express
it, that our atmosphere is a compound of all the fluids which are susceptible
of the vaporous or permanently elastic state, in the usual temperature, and
under the common pressure. 3dly, That it is not impossible we may
discover, in our atmosphere, certain substances naturally very compact,
even metals themselves; as a metallic substance, for instance, only a little
more volatile than mercury, might exist in that situation.
Amongst the fluids with which we are acquainted, some, as water and
alkohol, are susceptible of mixing with each other in all proportions;
whereas others, on the contrary, as quicksilver, water, and oil, can only form
a momentary union; and, after being mixed together, separate and arrange
themselves according to their specific gravities. The same thing ought to, or
at least may, take place in the atmosphere. It is possible, and even extremely
probable, that, both at the first creation, and every day, gasses are formed,
which are difficultly miscible with atmospheric air, and are continually
separating from it. If these gasses be specifically lighter than the general
atmospheric mass, they must, of course, gather in the higher regions, and
form strata that float upon the common air. The phenomena which
accompany igneous meteors induce me to believe, that there exists in the
upper parts of our atmosphere a stratum of inflammable fluid in contact
with those strata of air which produce the phenomena of the aurora borealis
and other fiery meteors.—I mean hereafter to pursue this subject in a
separate treatise.

FOOTNOTES:
[8] The degree of pressure which they undergo must be taken into account. E.

CHAP. III.
Analysis of Atmospheric Air, and its Division into two Elastic
Fluids; the one fit for Respiration, the other incapable of being
respired.

From what has been premised, it follows, that our atmosphere is composed
of a mixture of every substance capable of retaining the gasseous or
aëriform state in the common temperature, and under the usual pressure
which it experiences. These fluids constitute a mass, in some measure
homogeneous, extending from the surface of the earth to the greatest height
hitherto attained, of which the density continually decreases in the inverse
ratio of the superincumbent weight. But, as I have before observed, it is
possible that this first stratum is surmounted by several others consisting of
very different fluids.
Our business, in this place, is to endeavour to determine, by experiments,
the nature of the elastic fluids which compose the inferior stratum of air
which we inhabit. Modern chemistry has made great advances in this
research; and it will appear by the following details that the analysis of
atmospherical air has been more rigorously determined than that of any
other substance of the class. Chemistry affords two general methods of
determining the constituent principles of bodies, the method of analysis,
and that of synthesis. When, for instance, by combining water with alkohol,
we form the species of liquor called, in commercial language, brandy or
spirit of wine, we certainly have a right to conclude, that brandy, or spirit of
wine, is composed of alkohol combined with water. We can produce the
same result by the analytical method; and in general it ought to be
considered as a principle in chemical science, never to rest satisfied without
both these species of proofs.
We have this advantage in the analysis of atmospherical air, being able both
to decompound it, and to form it a new in the most satisfactory manner. I
shall, however, at present confine myself to recount such experiments as are
most conclusive upon this head; and I may consider most of these as my

own, having either first invented them, or having repeated those of others,
with the intention of analysing atmospherical air, in perfectly new points of
view.
I took a matrass (A, fig. 14. plate II.) of about 36 cubical inches capacity,
having a long neck B C D E, of six or seven lines internal diameter, and
having bent the neck as in Plate IV. Fig. 2. so as to allow of its being placed
in the furnace M M N N, in such a manner that the extremity of its neck E
might be inserted under a bell-glass F G, placed in a trough of quicksilver R
R S S; I introduced four ounces of pure mercury into the matrass, and, by
means of a syphon, exhausted the air in the receiver F G, so as to raise the
quicksilver to L L, and I carefully marked the height at which it stood by
pasting on a slip of paper. Having accurately noted the height of the
thermometer and barometer, I lighted a fire in the furnace M M N N, which
I kept up almost continually during twelve days, so as to keep the
quicksilver always almost at its boiling point. Nothing remarkable took
place during the first day: The Mercury, though not boiling, was continually
evaporating, and covered the interior surface of the vessels with small
drops, at first very minute, which gradually augmenting to a sufficient size,
fell back into the mass at the bottom of the vessel. On the second day, small
red particles began to appear on the surface of the mercury, which, during
the four or five following days, gradually increased in size and number;
after which they ceased to increase in either respect. At the end of twelve
days, seeing that the calcination of the mercury did not at all increase, I
extinguished the fire, and allowed the vessels to cool. The bulk of air in the
body and neck of the matrass, and in the bell-glass, reduced to a medium of
28 inches of the barometer and 10° (54.5°) of the thermometer, at the
commencement of the experiment was about 50 cubical inches. At the end
of the experiment the remaining air, reduced to the same medium pressure
and temperature, was only between 42 and 43 cubical inches; consequently
it had lost about 1/6 of its bulk. Afterwards, having collected all the red
particles, formed during the experiment, from the running mercury in which
they floated, I found these to amount to 45 grains.
I was obliged to repeat this experiment several times, as it is difficult in one
experiment both to preserve the whole air upon which we operate, and to
collect the whole of the red particles, or calx of mercury, which is formed
during the calcination. It will often happen in the sequel, that I shall, in this

manner, give in one detail the results of two or three experiments of the
same nature.
The air which remained after the calcination of the mercury in this
experiment, and which was reduced to 5/6 of its former bulk, was no longer
fit either for respiration or for combustion; animals being introduced into it
were suffocated in a few seconds, and when a taper was plunged into it, it
was extinguished as if it had been immersed into water.
In the next place, I took the 45 grains of red matter formed during this
experiment, which I put into a small glass retort, having a proper apparatus
for receiving such liquid, or gasseous product, as might be extracted:
Having applied a fire to the retort in a furnace, I observed that, in
proportion as the red matter became heated, the intensity of its colour
augmented. When the retort was almost red hot, the red matter began
gradually to decrease in bulk, and in a few minutes after it disappeared
altogether; at the same time 41-1/2 grains of running mercury were
collected in the recipient, and 7 or 8 cubical inches of elastic fluid, greatly
more capable of supporting both respiration and combustion than
atmospherical air, were collected in the bell-glass.
A part of this air being put into a glass tube of about an inch diameter,
showed the following properties: A taper burned in it with a dazzling
splendour, and charcoal, instead of consuming quietly as it does in common
air, burnt with a flame, attended with a decrepitating noise, like phosphorus,
and threw out such a brilliant light that the eyes could hardly endure it. This
species of air was discovered almost at the same time by Mr Priestley, Mr
Scheele, and myself. Mr Priestley gave it the name of dephlogisticated air,
Mr Scheele called it empyreal air. At first I named it highly respirable air,
to which has since been substituted the term of vital air. We shall presently
see what we ought to think of these denominations.
In reflecting upon the circumstances of this experiment, we readily
perceive, that the mercury, during its calcination, absorbs the salubrious and
respirable part of the air, or, to speak more strictly, the base of this
respirable part; that the remaining air is a species of mephitis, incapable of
supporting combustion or respiration; and consequently that atmospheric air
is composed of two elastic fluids of different and opposite qualities. As a

proof of this important truth, if we recombine these two elastic fluids,
which we have separately obtained in the above experiment, viz. the 42
cubical inches of mephitis, with the 8 cubical inches of respirable air, we
reproduce an air precisely similar to that of the atmosphere, and possessing
nearly the same power of supporting combustion and respiration, and of
contributing to the calcination of metals.
Although this experiment furnishes us with a very simple means of
obtaining the two principal elastic fluids which compose our atmosphere,
separate from each other, yet it does not give us an exact idea of the
proportion in which these two enter into its composition: For the attraction
of mercury to the respirable part of the air, or rather to its base, is not
sufficiently strong to overcome all the circumstances which oppose this
union. These obstacles are the mutual adhesion of the two constituent parts
of the atmosphere for each other, and the elective attraction which unites the
base of vital air with caloric; in consequence of these, when the calcination
ends, or is at least carried as far as is possible, in a determinate quantity of
atmospheric air, there still remains a portion of respirable air united to the
mephitis, which the mercury cannot separate. I shall afterwards show, that,
at least in our climate, the atmospheric air is composed of respirable and
mephitic airs, in the proportion of 27 and 73; and I shall then discuss the
causes of the uncertainty which still exists with respect to the exactness of
that proportion.
Since, during the calcination of mercury, air is decomposed, and the base of
its respirable part is fixed and combined with the mercury, it follows, from
the principles already established, that caloric and light must be disengaged
during the process: But the two following causes prevent us from being
sensible of this taking place: As the calcination lasts during several days,
the disengagement of caloric and light, spread out in a considerable space of
time, becomes extremely small for each particular moment of that time, so
as not to be perceptible; and, in the next place, the operation being carried
on by means of fire in a furnace, the heat produced by the calcination itself
becomes confounded with that proceeding from the furnace. I might add the
respirable part of the air, or rather its base, in entering into combination
with the mercury, does not part with all the caloric which it contained, but
still retains a part of it after forming the new compound; but the discussion

of this point, and its proofs from experiment, do not belong to this part of
our subject.
It is, however, easy to render this disengagement of caloric and light evident
to the senses, by causing the decomposition of air to take place in a more
rapid manner. And for this purpose, iron is excellently adapted, as it
possesses a much stronger affinity for the base of respirable air than
mercury. The elegant experiment of Mr Ingenhouz, upon the combustion of
iron, is well known. Take a piece of fine iron wire, twisted into a spiral,
(BC, Plate IV. Fig. 17.) fix one of its extremities B into the cork A, adapted
to the neck of the bottle DEFG, and fix to the other extremity of the wire C,
a small morsel of tinder. Matters being thus prepared, fill the bottle DEFG
with air deprived of its mephitic part; then light the tinder, and introduce it
quickly with the wire upon which it is fixed, into the bottle which you stop
up with the cork A, as is shown in the figure (17 Plate IV.) The instant the
tinder comes into contact with the vital air it begins to burn with great
intensity; and, communicating the inflammation to the iron-wire, it too
takes fire, and burns rapidly, throwing out brilliant sparks, which fall to the
bottom of the vessel in rounded globules, which become black in cooling,
but retain a degree of metallic splendour. The iron thus burnt is more brittle
even than glass, and is easily reduced into powder, and is still attractable by
the magnet, though not so powerfully as it was before combustion. As Mr
Ingenhouz has neither examined the change produced on iron, nor upon the
air by this operation, I have repeated the experiment under different
circumstances, in an apparatus adapted to answer my particular views, as
follows.
Having filled a bell-glass (A, Plate IV. Fig. 3.) of about six pints measure,
with pure air, or the highly respirable part of air, I transported this jar by
means of a very flat vessel, into a quicksilver bath in the bason BC, and I
took care to render the surface of the mercury perfectly dry both within and
without the jar with blotting paper. I then provided a small capsule of china-
ware D, very flat and open, in which I placed some small pieces of iron,
turned spirally, and arranged in such a way as seemed most favourable for
the combustion being communicated to every part. To the end of one of
these pieces of iron was fixed a small morsel of tinder, to which was added
about the sixteenth part of a grain of phosphorus, and, by raising the bell-
glass a little, the china capsule, with its contents, were introduced into the

pure air. I know that, by this means, some common air must mix with the
pure air in the glass; but this, when it is done dexterously, is so very trifling,
as not to injure the success of the experiment. This being done, a part of the
air is sucked out from the bell-glass, by means of a syphon GHI, so as to
raise the mercury within the glass to EF; and, to prevent the mercury from
getting into the syphon, a small piece of paper is twisted round its
extremity. In sucking out the air, if the motion of the lungs only be used, we
cannot make the mercury rise above an inch or an inch and a half; but, by
properly using the muscles of the mouth, we can, without difficulty, cause it
to rise six or seven inches.
I next took an iron wire, (MN, Plate IV. Fig. 16.) properly bent for the
purpose, and making it red hot in the fire, passed it through the mercury
into the receiver, and brought it in contact with the small piece of
phosphorus attached to the tinder. The phosphorus instantly takes fire,
which communicates to the tinder, and from that to the iron. When the
pieces have been properly arranged, the whole iron burns, even to the last
particle, throwing out a white brilliant light similar to that of Chinese
fireworks. The great heat produced by this combustion melts the iron into
round globules of different sizes, most of which fall into the China cup; but
some are thrown out of it, and swim upon the surface of the mercury. At the
beginning of the combustion, there is a slight augmentation in the volume
of the air in the bell-glass, from the dilatation caused by the heat; but,
presently afterwards, a rapid diminution of the air takes place, and the
mercury rises in the glass; insomuch that, when the quantity of iron is
sufficient, and the air operated upon is very pure, almost the whole air
employed is absorbed.
It is proper to remark in this place, that, unless in making experiments for
the purpose of discovery, it is better to be contented with burning a
moderate quantity of iron; for, when this experiment is pushed too far, so as
to absorb much of the air, the cup D, which floats upon the quicksilver,
approaches too near the bottom of the bell-glass; and the great heat
produced, which is followed by a very sudden cooling, occasioned by the
contact of the cold mercury, is apt to break the glass. In which case, the
sudden fall of the column of mercury, which happens the moment the least
flaw is produced in the glass, causes such a wave, as throws a great part of
the quicksilver from the bason. To avoid this inconvenience, and to ensure

success to the experiment, one gross and a half of iron is sufficient to burn
in a bell-glass, which holds about eight pints of air. The glass ought
likewise to be strong, that it may be able to bear the weight of the column of
mercury which it has to support.
By this experiment, it is not possible to determine, at one time, both the
additional weight acquired by the iron, and the changes which have taken
place in the air. If it is wished to ascertain what additional weight has been
gained by the iron, and the proportion between that and the air absorbed, we
must carefully mark upon the bell-glass, with a diamond, the height of the
mercury, both before and after the experiment[9]. After this, the syphon
(GH, Pl. IV. fig. 3.) guarded, as before, with a bit of paper, to prevent its
filling with mercury, is to be introduced under the bell-glass, having the
thumb placed upon the extremity, G, of the syphon, to regulate the passage
of the air; and by this means the air is gradually admitted, so as to let the
mercury fall to its level. This being done, the bell-glass is to be carefully
removed, the globules of melted iron contained in the cup, and those which
have been scattered about, and swim upon the mercury, are to be accurately
collected, and the whole is to be weighed. The iron will be found in that
state called martial ethiops by the old chemists, possessing a degree of
metallic brilliancy, very friable, and readily reducible into powder, under
the hammer, or with a pestle and mortar. If the experiment has succeeded
well, from 100 grains of iron will be obtained 135 or 136 grains of ethiops,
which is an augmentation of 35 per cent.
If all the attention has been paid to this experiment which it deserves, the air
will be found diminished in weight exactly equal to what the iron has
gained. Having therefore burnt 100 grains of iron, which has acquired an
additional weight of 35 grains, the diminution of air will be found exactly
70 cubical inches; and it will be found, in the sequel, that the weight of vital
air is pretty nearly half a grain for each cubical inch; so that, in effect, the
augmentation of weight in the one exactly coincides with the loss of it in
the other.
I shall observe here, once for all, that, in every experiment of this kind, the
pressure and temperature of the air, both before and after the experiment,
must be reduced, by calculation, to a common standard of 10° (54.5°) of the
thermometer, and 28 inches of the barometer. Towards the end of this work,

the manner of performing this very necessary reduction will be found
accurately detailed.
If it be required to examine the nature of the air which remains after this
experiment, we must operate in a somewhat different manner. After the
combustion is finished, and the vessels have cooled, we first take out the
cup, and the burnt iron, by introducing the hand through the quicksilver,
under the bell-glass; we next introduce some solution of potash, or caustic
alkali, or of the sulphuret of potash, or such other substance as is judged
proper for examining their action upon the residuum of air. I shall, in the
sequel, give an account of these methods of analysing air, when I have
explained the nature of these different substances, which are only here in a
manner accidentally mentioned. After this examination, so much water must
be let into the glass as will displace the quicksilver, and then, by means of a
shallow dish placed below the bell-glass, it is to be removed into the
common water pneumato-chemical apparatus, where the air remaining may
be examined at large, and with great facility.
When very soft and very pure iron has been employed in this experiment,
and, if the combustion has been performed in the purest respirable or vital
air, free from all admixture of the noxious or mephitic part, the air which
remains after the combustion will be found as pure as it was before; but it is
difficult to find iron entirely free from a small portion of charry matter,
which is chiefly abundant in steel. It is likewise exceedingly difficult to
procure the pure air perfectly free from some admixture of mephitis, with
which it is almost always contaminated; but this species of noxious air does
not, in the smallest degree, disturb the result of the experiment, as it is
always found at the end exactly in the same proportion as at the beginning.
I mentioned before, that we have two ways of determining the constituent
parts of atmospheric air, the method of analysis, and that by synthesis. The
calcination of mercury has furnished us with an example of each of these
methods, since, after having robbed the respirable part of its base, by means
of the mercury, we have restored it, so as to recompose an air precisely
similar to that of the atmosphere. But we can equally accomplish this
synthetic composition of atmospheric air, by borrowing the materials of
which it is composed from different kingdoms of nature. We shall see
hereafter that, when animal substances are dissolved in the nitric acid, a

great quantity of gas is disengaged, which extinguishes light, and is unfit
for animal respiration, being exactly similar to the noxious or mephitic part
of atmospheric air. And, if we take 73 parts, by weight, of this elastic fluid,
and mix it with 27 parts of highly respirable air, procured from calcined
mercury, we will form an elastic fluid precisely similar to atmospheric air in
all its properties.
There are many other methods of separating the respirable from the noxious
part of the atmospheric air, which cannot be taken notice of in this part,
without anticipating information, which properly belongs to the subsequent
chapters. The experiments already adduced may suffice for an elementary
treatise; and, in matters of this nature, the choice of our evidences is of far
greater consequence than their number.
I shall close this article, by pointing out the property which atmospheric air,
and all the known gasses, possess of dissolving water, which is of great
consequence to be attended to in all experiments of this nature. Mr Saussure
found, by experiment, that a cubical foot of atmospheric air is capable of
holding 12 grains of water in solution: Other gasses, as the carbonic acid,
appear capable of dissolving a greater quantity; but experiments are still
wanting by which to determine their several proportions. This water, held in
solution by gasses, gives rise to particular phenomena in many experiments,
which require great attention, and which has frequently proved the source
of great errors to chemists in determining the results of their experiments.

FOOTNOTES:
[9] It will likewise be necessary to take care that the air contained in the glass,
both before and after the experiment, be reduced to a common temperature and
pressure, otherwise the results of the following calculations will be fallacious.—
E.

CHAP. IV.
Nomenclature of the several Constituent Parts of Atmospheric
Air.

Hitherto I have been obliged to make use of circumlocution, to express the
nature of the several substances which constitute our atmosphere, having
provisionally used the terms of respirable and noxious, or non-respirable
parts of the air. But the investigations I mean to undertake require a more
direct mode of expression; and, having now endeavoured to give simple and
distinct ideas of the different substances which enter into the composition of
the atmosphere, I shall henceforth express these ideas by words equally
simple.
The temperature of our earth being very near to that at which water
becomes solid, and reciprocally changes from solid to fluid, and as this
phenomenon takes place frequently under our observation, it has very
naturally followed, that, in the languages of at least every climate subjected
to any degree of winter, a term has been used for signifying water in the
state of solidity, when deprived of its caloric. The same, however, has not
been found necessary with respect to water reduced to the state of vapour
by an additional dose of caloric; since those persons who do not make a
particular study of objects of this kind, are still ignorant that water, when in
a temperature only a little above the boiling heat, is changed into an elastic
aëriform fluid, susceptible, like all other gasses, of being received and
contained in vessels, and preserving its gasseous form so long as it remains
at the temperature of 80° (212°), and under a pressure not exceeding 28
inches of the mercurial barometer. As this phenomenon has not been
generally observed, no language has used a particular term for expressing
water in this state[10]; and the same thing occurs with all fluids, and all
substances, which do not evaporate in the common temperature, and under
the usual pressure of our atmosphere.
For similar reasons, names have not been given to the liquid or concrete
states of most of the aëriform fluids: These were not known to arise from

the combination of caloric with certain bases; and, as they had not been
seen either in the liquid or solid states, their existence, under these forms,
was even unknown to natural philosophers.
We have not pretended to make any alteration upon such terms as are
sanctified by ancient custom; and, therefore, continue to use the words
water and ice in their common acceptation: We likewise retain the word air,
to express that collection of elastic fluids which composes our atmosphere;
but we have not thought it necessary to preserve the same respect for
modern terms, adopted by latter philosophers, having considered ourselves
as at liberty to reject such as appeared liable to occasion erroneous ideas of
the substances they are meant to express, and either to substitute new terms,
or to employ the old ones, after modifying them in such a manner as to
convey more determinate ideas. New words have been drawn, chiefly from
the Greek language, in such a manner as to make their etymology convey
some idea of what was meant to be represented; and these we have always
endeavoured to make short, and of such a nature as to be changeable into
adjectives and verbs.
Following these principles, we have, after Mr Macquer's example, retained
the term gas, employed by Vanhelmont, having arranged the numerous class
of elastic aëriform fluids under that name, excepting only atmospheric air.
Gas, therefore, in our nomenclature, becomes a generic term, expressing the
fullest degree of saturation in any body with caloric; being, in fact, a term
expressive of a mode of existence. To distinguish each species of gas, we
employ a second term from the name of the base, which, saturated with
caloric, forms each particular gas. Thus, we name water combined to
saturation with caloric, so as to form an elastic fluid, aqueous gas; ether,
combined in the same manner, etherial gas; the combination of alkohol
with caloric, becomes alkoholic gas; and, following the same principles, we
have muriatic acid gas, ammoniacal gas, and so on of every substance
susceptible of being combined with caloric, in such a manner as to assume
the gasseous or elastic aëriform state.
We have already seen, that the atmospheric air is composed of two gasses,
or aëriform fluids, one of which is capable, by respiration, of contributing to
animal life, and in which metals are calcinable, and combustible bodies may
burn; the other, on the contrary, is endowed with directly opposite qualities;

it cannot be breathed by animals, neither will it admit of the combustion of
inflammable bodies, nor of the calcination of metals. We have given to the
base of the former, or respirable portion of the air, the name of oxygen, from
οξυς acidum, and γεινομας, gignor; because, in reality, one of the most
general properties of this base is to form acids, by combining with many
different substances. The union of this base with caloric we term oxygen
gas, which is the same with what was formerly called pure, or vital air. The
weight of this gas, at the temperature of 10° (54.50), and under a pressure
equal to 28 inches of the barometer, is half a grain for each cubical inch, or
one ounce and a half to each cubical foot.
The chemical properties of the noxious portion of atmospheric air being
hitherto but little known, we have been satisfied to derive the name of its
base from its known quality of killing such animals as are forced to breathe
it, giving it the name of azote, from the Greek privitive particle α and ξαη,
vita; hence the name of the noxious part of atmospheric air is azotic gas; the
weight of which, in the same temperature, and under the same pressure, is 1
oz. 2 gros. and 48 grs. to the cubical foot, or 0.4444 of a grain to the cubical
inch. We cannot deny that this name appears somewhat extraordinary; but
this must be the case with all new terms, which cannot be expected to
become familiar until they have been some time in use. We long
endeavoured to find a more proper designation without success; it was at
first proposed to call it alkaligen gas, as, from the experiments of Mr
Berthollet, it appears to enter into the composition of ammoniac, or volatile
alkali; but then, we have as yet no proof of its making one of the constituent
elements of the other alkalies; beside, it is proved to compose a part of the
nitric acid, which gives as good reason to have called it nitrigen. For these
reasons, finding it necessary to reject any name upon systematic principles,
we have considered that we run no risk of mistake in adopting the terms of
azote, and azotic gas, which only express a matter of fact, or that property
which it possesses, of depriving such animals as breathe it of their lives.
I should anticipate subjects more properly reserved for the subsequent
chapters, were I in this place to enter upon the nomenclature of the several
species of gasses: It is sufficient, in this part of the work, to establish the
principles upon which their denominations are founded. The principal merit
of the nomenclature we have adopted is, that, when once the simple
elementary substance is distinguished by an appropriate term, the names of

all its compounds derive readily, and necessarily, from this first
denomination.

FOOTNOTES:
[10] In English, the word steam is exclusively appropriated to water in the state
of vapour. E.

CHAP. V.
Of the Decomposition of Oxygen Gas by Sulphur, Phosphorus,
and Charcoal—and of the Formation of Acids in general.

In performing experiments, it is a necessary principle, which ought never to
be deviated from, that they be simplified as much as possible, and that
every circumstance capable of rendering their results complicated be
carefully removed. Wherefore, in the experiments which form the object of
this chapter, we have never employed atmospheric air, which is not a simple
substance. It is true, that the azotic gas, which forms a part of its mixture,
appears to be merely passive during combustion and calcination; but,
besides that it retards these operations very considerably, we are not certain
but it may even alter their results in some circumstances; for which reason,
I have thought it necessary to remove even this possible cause of doubt, by
only making use of pure oxygen gas in the following experiments, which
show the effects produced by combustion in that gas; and I shall advert to
such differences as take place in the results of these, when the oxygen gas,
or pure vital air, is mixed, in different proportions, with azotic gas.
Having filled a bell-glass (A. Pl. iv. fig. 3), of between five and six pints
measure, with oxygen gas, I removed it from the water trough, where it was
filled, into the quicksilver bath, by means of a shallow glass dish slipped
underneath, and having dried the mercury, I introduced 61-1/4 grains of
Kunkel's phosphorus in two little China cups, like that represented at D, fig.
3. under the glass A; and that I might set fire to each of the portions of
phosphorus separately, and to prevent the one from catching fire from the
other, one of the dishes was covered with a piece of flat glass. I next raised
the quicksilver in the bell-glass up to E F, by sucking out a sufficient
portion of the gas by means of the syphon G H I. After this, by means of the
crooked iron wire (fig. 16.), made red hot, I set fire to the two portions of
phosphorus successively, first burning that portion which was not covered
with the piece of glass. The combustion was extremely rapid, attended with
a very brilliant flame, and considerable disengagement of light and heat. In

consequence of the great heat induced, the gas was at first much dilated, but
soon after the mercury returned to its level, and a considerable absorption of
gas took place; at the same time, the whole inside of the glass became
covered with white light flakes of concrete phosphoric acid.
At the beginning of the experiment, the quantity of oxygen gas, reduced, as
above directed, to a common standard, amounted to 162 cubical inches;
and, after the combustion was finished, only 23-1/4 cubical inches, likewise
reduced to the standard, remained; so that the quantity of oxygen gas
absorbed during the combustion was 138-3/4 cubical inches, equal to
69.375 grains.
A part of the phosphorus remained unconsumed in the bottom of the cups,
which being washed on purpose to separate the acid, weighed about 16-1/4
grains; so that about 45 grains of phosphorus had been burned: But, as it is
hardly possible to avoid an error of one or two grains, I leave the quantity
so far qualified. Hence, as nearly 45 grains of phosphorus had, in this
experiment, united with 69.375 grains of oxygen, and as no gravitating
matter could have escaped through the glass, we have a right to conclude,
that the weight of the substance resulting from the combustion in form of
white flakes, must equal that of the phosphorus and oxygen employed,
which amounts to 114.375 grains. And we shall presently find, that these
flakes consisted entirely of a solid or concrete acid. When we reduce these
weights to hundredth parts, it will be found, that 100 parts of phosphorus
require 154 parts of oxygen for saturation, and that this combination will
produce 254 parts of concrete phosphoric acid, in form of white fleecy
flakes.
This experiment proves, in the most convincing manner, that, at a certain
degree of temperature, oxygen possesses a stronger elective attraction, or
affinity, for phosphorus than for caloric; that, in consequence of this, the
phosphorus attracts the base of oxygen gas from the caloric, which, being
set free, spreads itself over the surrounding bodies. But, though this
experiment be so far perfectly conclusive, it is not sufficiently rigorous, as,
in the apparatus described, it is impossible to ascertain the weight of the
flakes of concrete acid which are formed; we can therefore only determine
this by calculating the weights of oxygen and phosphorus employed; but as,
in physics, and in chemistry, it is not allowable to suppose what is capable

of being ascertained by direct experiment, I thought it necessary to rep at
this experiment, as follows, upon a larger scale, and by means of a different
apparatus.
I took a large glass baloon (A. Pl. iv. fig. 4.) with an opening three inches
diameter, to which was fitted a crystal stopper ground with emery, and
pierced with two holes for the tubes yyy, xxx. Before shutting the baloon
with its stopper, I introduced the support BC, surmounted by the china cup
D, containing 150 grs. of phosphorus; the stopper was then fitted to the
opening of the baloon, luted with fat lute, and covered with slips of linen
spread with quick-lime and white of eggs: When the lute was perfectly dry,
the weight of the whole apparatus was determined to within a grain, or a
grain and a half. I next exhausted the baloon, by means of an air pump
applied to the tube xxx, and then introduced oxygen gas by means of the
tube yyy, having a stop cock adapted to it. This kind of experiment is most
readily and most exactly performed by means of the hydro-pneumatic
machine described by Mr Meusnier and me in the Memoirs of the Academy
for 1782, pag. 466. and explained in the latter part of this work, with several
important additions and corrections since made to it by Mr Meusnier. With
this instrument we can readily ascertain, in the most exact manner, both the
quantity of oxygen gas introduced into the baloon, and the quantity
consumed during the course of the experiment.
When all things were properly disposed, I set fire to the phosphorus with a
burning glass. The combustion was extremely rapid, accompanied with a
bright flame, and much heat; as the operation went on, large quantities of
white flakes attached themselves to the inner surface of the baloon, so that
at last it was rendered quite opake. The quantity of these flakes at last
became so abundant, that, although fresh oxygen gas was continually
supplied, which ought to have supported the combustion, yet the
phosphorus was soon extinguished. Having allowed the apparatus to cool
completely, I first ascertained the quantity of oxygen gas employed, and
weighed the baloon accurately, before it was opened. I next washed, dried,
and weighed the small quantity of phosphorus remaining in the cup, on
purpose to determine the whole quantity of phosphorus consumed in the
experiment; this residuum of the phosphorus was of a yellow ochrey colour.
It is evident, that by these several precautions, I could easily determine, 1st,
the weight of the phosphorus consumed; 2d, the weight of the flakes

produced by the combustion; and, 3d, the weight of the oxygen which had
combined with the phosphorus. This experiment gave very nearly the same
results with the former, as it proved that the phosphorus, during its
combustion, had absorbed a little more than one and a half its weight of
oxygen; and I learned with more certainty, that the weight of the new
substance, produced in the experiment, exactly equalled the sum of the
weights of the phosphorus consumed, and oxygen absorbed, which indeed
was easily determinable a priori. If the oxygen gas employed be pure, the
residuum after combustion is as pure as the gas employed; this proves that
nothing escapes from the phosphorus, capable of altering the purity of the
oxygen gas, and that the only action of the phosphorus is to separate the
oxygen from the caloric, with which it was before united.
I mentioned above, that when any combustible body is burnt in a hollow
sphere of ice, or in an apparatus properly constructed upon that principle,
the quantity of ice melted during the combustion is an exact measure of the
quantity of caloric disengaged. Upon this head, the memoir given by M. de
la Place and me, Aº. 1780, p. 355, may be consulted. Having submitted the
combustion of phosphorus to this trial, we found that one pound of
phosphorus melted a little more than 100 pounds of ice during its
combustion.
The combustion of phosphorus succeeds equally well in atmospheric air as
in oxygen gas, with this difference, that the combustion is vastly slower,
being retarded by the large proportion of azotic gas mixed with the oxygen
gas, and that only about one-fifth part of the air employed is absorbed,
because as the oxygen gas only is absorbed, the proportion of the azotic gas
becomes so great toward the close of the experiment, as to put an end to the
combustion.
I have already shown, that phosphorus is changed by combustion into an
extremely light, white, flakey matter; and its properties are entirely altered
by this transformation: From being insoluble in water, it becomes not only
soluble, but so greedy of moisture, as to attract the humidity of the air with
astonishing rapidity; by this means it is converted into a liquid,
considerably more dense, and of more specific gravity than water. In the
state of phosphorus before combustion, it had scarcely any sensible taste, by
its union with oxygen it acquires an extremely sharp and sour taste: in a

word, from one of the class of combustible bodies, it is changed into an
incombustible substance, and becomes one of those bodies called acids.
This property of a combustible substance to be converted into an acid, by
the addition of oxygen, we shall presently find belongs to a great number of
bodies: Wherefore, strict logic requires that we should adopt a common
term for indicating all these operations which produce analogous results;
this is the true way to simplify the study of science, as it would be quite
impossible to bear all its specifical details in the memory, if they were not
classically arranged. For this reason, we shall distinguish this conversion of
phosphorus into an acid, by its union with oxygen, and in general every
combination of oxygen with a combustible substance, by the term of
oxygenation: from which I shall adopt the verb to oxygenate, and of
consequence shall say, that in oxygenating phosphorus we convert it into an
acid.
Sulphur is likewise a combustible body, or, in other words, it is a body
which possesses the power of decomposing oxygen gas, by attracting the
oxygen from the caloric with which it was combined. This can very easily
be proved, by means of experiments quite similar to those we have given
with phosphorus; but it is necessary to premise, that in these operations with
sulphur, the same accuracy of result is not to be expected as with
phosphorus; because the acid which is formed by the combustion of sulphur
is difficultly condensible, and because sulphur burns with more difficulty,
and is soluble in the different gasses. But I can safely assert, from my own
experiments, that sulphur in burning absorbs oxygen gas; that the resulting
acid is considerably heavier than the sulphur burnt; that its weight is equal
to the sum of the weights of the sulphur which has been burnt, and of the
oxygen absorbed; and, lastly that this acid is weighty, incombustible, and
miscible with water in all proportions: The only uncertainty remaining upon
this head, is with regard to the proportions of sulphur and of oxygen which
enter into the composition of the acid.
Charcoal, which, from all our present knowledge regarding it, must be
considered as a simple combustible body, has likewise the property of
decomposing oxygen gas, by absorbing its base from the caloric: But the
acid resulting from this combustion does not condense in the common
temperature; under the pressure of our atmosphere, it remains in the state of

gas, and requires a large proportion of water to combine with or be
dissolved in. This acid has, however, all the known properties of other
acids, though in a weaker degree, and combines, like them, with all the
bases which are susceptible of forming neutral salts.
The combustion of charcoal in oxygen gas, may be effected like that of
phosphorus in the bell-glass, (A. Pl. IV. fig. 3.) placed over mercury: but, as
the heat of red hot iron is not sufficient to set fire to the charcoal, we must
add a small morsel of tinder, with a minute particle of phosphorus, in the
same manner as directed in the experiment for the combustion of iron. A
detailed account of this experiment will be found in the memoirs of the
academy for 1781, p. 448. By that experiment it appears, that 28 parts by
weight of charcoal require 72 parts of oxygen for saturation, and that the
aëriform acid produced is precisely equal in weight to the sum of the
weights of the charcoal and oxygen gas employed. This aëriform acid was
called fixed or fixable air by the chemists who first discovered it; they did
not then know whether it was air resembling that of the atmosphere, or
some other elastic fluid, vitiated and corrupted by combustion; but since it
is now ascertained to be an acid, formed like all others by the oxygenation
of its peculiar base, it is obvious that the name of fixed air is quite
ineligible[11].
By burning charcoal in the apparatus mentioned p. 60, Mr de la Place and I
found that one lib. of charcoal melted 96 libs. 6 oz. of ice; that, during the
combustion, 2 libs. 9 oz. 1 gros. 10 grs. of oxygen were absorbed, and that
3 libs. 9 oz. 1 gros. 10 grs. of acid gas were formed. This gas weighs 0.695
parts of a grain for each cubical inch, in the common standard temperature
and pressure mentioned above, so that 34,242 cubical inches of acid gas are
produced by the combustion of one pound of charcoal.
I might multiply these experiments, and show by a numerous succession of
facts, that all acids are formed by the combustion of certain substances; but
I am prevented from doing so in place, by the plan which I have laid down,
of proceeding only from facts already ascertained, to such as are unknown,
and of drawing my examples only from circumstances already explained. In
the mean time, however, the three examples above cited may suffice for
giving a clear and accurate conception of the manner in which acids are
formed. By these it may be clearly seen, that oxygen is an element common

to them all, which constitutes their acidity; and that they differ from each
other, according to the nature of the oxygenated or acidified substance. We
must therefore, in every acid, carefully distinguish between the acidifiable,
base, which Mr de Morveau calls the radical, and the acidifiing principle or
oxygen.

FOOTNOTES:
[11] It may be proper to remark, though here omitted by the author, that, in
conformity with the general principles of the new nomenclature, this acid is by
Mr Lavoisier and his coleagues called the carbonic acid, and when in the
aëriform state carbonic acid gas. E.

CHAP. VI.
Of the Nomenclature of Acids in general, and particularly of
those drawn from Nitre and Sea-Salt.

It becomes extremely easy, from the principles laid down in the preceding
chapter, to establish a systematic nomenclature for the acids: The word
acid, being used as a generic term, each acid falls to be distinguished in
language, as in nature, by the name of its base or radical. Thus, we give the
generic name of acids to the products of the combustion or oxygenation of
phosphorus, of sulphur, and of charcoal; and these products are respectively
named, the phosphoric acid, the sulphuric acid, and the carbonic acid.
There is however, a remarkable circumstance in the oxygenation of
combustible bodies, and of a part of such bodies as are convertible into
acids, that they are susceptible of different degrees of saturation with
oxygen, and that the resulting acids, though formed by the union of the
same elements, are possessed of different properties, depending upon that
difference of proportion. Of this, the phosphoric acid, and more especially
the sulphuric, furnishes us with examples. When sulphur is combined with a
small proportion of oxygen, it forms, in this first or lower degree of
oxygenation, a volatile acid, having a penetrating odour, and possessed of
very particular qualities. By a larger proportion of oxygen, it is changed into
a fixed, heavy acid, without any odour, and which, by combination with
other bodies, gives products quite different from those furnished by the
former. In this instance, the principles of our nomenclature seem to fail; and
it seems difficult to derive such terms from the name of the acidifiable base,
as shall distinctly express these two degrees of saturation, or oxygenation,
without circumlocution. By reflection, however, upon the subject, or
perhaps rather from the necessity of the case, we have thought it allowable
to express these varieties in the oxygenation of the acids, by simply varying
the termination of their specific names. The volatile acid produced from
sulphur was anciently known to Stahl under the name of sulphurous
acid[12]. We have preserved that term for this acid from sulphur under-

saturated with oxygen; and distinguish the other, or completely saturated or
oxygenated acid, by the name of sulphuric acid. We shall therefore say, in
this new chemical language, that sulphur, in combining with oxygen, is
susceptible of two degrees of saturation; that the first, or lesser degree,
constitutes sulphurous acid, which is volatile and penetrating; whilst the
second, or higher degree of saturation, produces sulphuric acid, which is
fixed and inodorous. We shall adopt this difference of termination for all the
acids which assume several degrees of saturation. Hence we have a
phosphorous and a phosphoric acid, an acetous and an acetic acid; and so
on, for others in similar circumstances.
This part of chemical science would have been extremely simple, and the
nomenclature of the acids would not have been at all perplexed, as it is now
in the old nomenclature, if the base or radical of each acid had been known
when the acid itself was discovered. Thus, for instance, phosphorus being a
known substance before the discovery of its acid, this latter was rightly
distinguished by a term drawn from the name of its acidifiable base. But
when, on the contrary, an acid happened to be discovered before its base, or
rather, when the acidifiable base from which it was formed remained
unknown, names were adopted for the two, which have not the smallest
connection; and thus, not only the memory became burthened with useless
appellations, but even the minds of students, nay even of experienced
chemists, became filled with false ideas, which time and reflection alone is
capable of eradicating. We may give an instance of this confusion with
respect to the acid sulphur: The former chemists having procured this acid
from the vitriol of iron, gave it the name of the vitriolic acid from the name
of the substance which produced it; and they were then ignorant that the
acid procured from sulphur by combustion was exactly the same.
The same thing happened with the aëriform acid formerly called fixed air; it
not being known that this acid was the result of combining charcoal with
oxygen, a variety of denominations have been given to it, not one of which
conveys just ideas of its nature or origin. We have found it extremely easy
to correct and modify the ancient language with respect to these acids
proceeding from known bases, having converted the name of vitriolic acid
into that of sulphuric, and the name of fixed air into that of carbonic acid;
but it is impossible to follow this plan with the acids whose bases are still
unknown; with these we have been obliged to use a contrary plan, and,

instead of forming the name of the acid from that of its base, have been
forced to denominate the unknown base from the name of the known acid,
as happens in the case of the acid which is procured from sea salt.
To disengage this acid from the alkaline base with which it is combined, we
have only to pour sulphuric acid upon sea-salt, immediately a brisk
effervescence takes place, white vapours arise, of a very penetrating odour,
and, by only gently heating the mixture, all the acid is driven off. As, in the
common temperature and pressure of our atmosphere, this acid is naturally
in the state of gas, we must use particular precautions for retaining it in
proper vessels. For small experiments, the most simple and most
commodious apparatus consists of a small retort G, (Pl. V. Fig. 5.), into
which the sea-salt is introduced, well dried[13], we then pour on some
concentrated sulphuric acid, and immediately introduce the beak of the
retort under little jars or bell-glasses A, (same Plate and Fig.), previously
filled with quicksilver. In proportion as the acid gas is disengaged, it passes
into the jar, and gets to the top of the quicksilver, which it displaces. When
the disengagement of the gas slackens, a gentle heat is applied to the retort,
and gradually increased till nothing more passes over. This acid gas has a
very strong affinity with water, which absorbs an enormous quantity of it,
as is proved by introducing a very thin layer of water into the glass which
contains the gas; for, in an instant, the whole acid gas disappears, and
combines with the water.
This latter circumstance is taken advantage of in laboratories and
manufactures, on purpose to obtain the acid of sea-salt in a liquid form; and
for this purpose the apparatus (Pl. IV. Fig. 1.) is employed. It consists, 1st,
of a tubulated retort A, into which the sea-salt, and after it the sulphuric
acid, are introduced through the opening H; 2d, of the baloon or recipient c,
b, intended for containing the small quantity of liquid which passes over
during the process; and, 3d, of a set of bottles, with two mouths, L, L, L, L,
half filled with water, intended for absorbing the gas disengaged by the
distillation. This apparatus will be more amply described in the latter part of
this work.
Although we have not yet been able, either to compose or to decompound
this acid of sea-salt, we cannot have the smallest doubt that it, like all other
acids, is composed by the union of oxygen with an acidifiable base. We

have therefore called this unknown substance the muriatic base, or muriatic
radical, deriving this name, after the example of Mr Bergman and Mr de
Morveau, from the Latin word muria, which was anciently used to signify
sea-salt. Thus, without being able exactly to determine the component parts
of muriatic acid, we design, by that term, a volatile acid, which retains the
form of gas in the common temperature and pressure of our atmosphere,
which combines with great facility, and in great quantity, with water, and
whose acidifiable base adheres so very intimately with oxygen, that no
method has hitherto been devised for separating them. If ever this
acidifiable base of the muriatic acid is discovered to be a known substance,
though now unknown in that capacity, it will be requisite to change its
present denomination for one analogous with that of its base.
In common with sulphuric acid, and several other acids, the muriatic is
capable of different degrees of oxygenation; but the excess of oxygen
produces quite contrary effects upon it from what the same circumstance
produces upon the acid of sulphur. The lower degree of oxygenation
converts sulphur into a volatile gasseous acid, which only mixes in small
proportions with water, whilst a higher oxygenation forms an acid
possessing much stronger acid properties, which is very fixed and cannot
remain in the state of gas but in a very high temperature, which has no
smell, and which mixes in large proportion with water. With muriatic acid,
the direct reverse takes place; an additional saturation with oxygen renders
it more volatile, of a more penetrating odour, less miscible with water, and
diminishes its acid properties. We were at first inclined to have
denominated these two degrees of saturation in the same manner as we had
done with the acid of sulphur, calling the less oxygenated muriatous acid,
and that which is more saturated with oxygen muriatic acid: But, as this
latter gives very particular results in its combinations, and as nothing
analogous to it is yet known in chemistry, we have left the name of muriatic
acid to the less saturated, and give the latter the more compounded
appellation of oxygenated muriatic acid.
Although the base or radical of the acid which is extracted from nitre or
saltpetre be better known, we have judged proper only to modify its name
in the same manner with that of the muriatic acid. It is drawn from nitre, by
the intervention of sulphuric acid, by a process similar to that described for
extracting the muriatic acid, and by means of the same apparatus (Pl. IV.

Fig. 1.). In proportion as the acid passes over, it is in part condensed in the
baloon or recipient, and the rest is absorbed by the water contained in the
bottles L,L,L,L; the water becomes first green, then blue, and at last yellow,
in proportion to the concentration of the acid. During this operation, a large
quantity of oxygen gas, mixed with a small proportion of azotic gas, is
disengaged.
This acid, like all others, is composed of oxygen, united to an acidifiable
base, and is even the first acid in which the existence of oxygen was well
ascertained. Its two constituent elements are but weakly united, and are
easily separated, by presenting any substance with which oxygen has a
stronger affinity than with the acidifiable base peculiar to this acid. By
some experiments of this kind, it was first discovered that azote, or the base
of mephitis or azotic gas, constituted its acidifiable base or radical; and
consequently that the acid of nitre was really an azotic acid, having azote
for its base, combined with oxygen. For these reasons, that we might be
consistent with our principles, it appeared necessary, either to call the acid
by the name of azotic, or to name the base nitric radical; but from either of
these we were dissuaded, by the following considerations. In the first place,
it seemed difficult to change the name of nitre or saltpetre, which has been
universally adopted in society, in manufactures, and in chemistry; and, on
the other hand, azote having been discovered by Mr Berthollet to be the
base of volatile alkali, or ammoniac, as well as of this acid, we thought it
improper to call it nitric radical. We have therefore continued the term of
azote to the base of that part of atmospheric air which is likewise the nitric
and ammoniacal radical; and we have named the acid of nitre, in its lower
and higher degrees of oxygenation, nitrous acid in the former, and nitric
acid in the latter state; thus preserving its former appellation properly
modified.
Several very respectable chemists have disapproved of this deference for
the old terms, and wished us to have persevered in perfecting a new
chemical language, without paying any respect for ancient usage; so that, by
thus steering a kind of middle course, we have exposed ourselves to the
censures of one sect of chemists, and to the expostulations of the opposite
party.

The acid of nitre is susceptible of assuming a great number of separate
states, depending upon its degree of oxygenation, or upon the proportions in
which azote and oxygen enter into its composition. By a first or lowest
degree of oxygenation, it forms a particular species of gas, which we shall
continue to name nitrous gas; this is composed nearly of two parts, by
weight, of oxygen combined with one part of azote; and in this state it is not
miscible with water. In this gas, the azote is by no means saturated with
oxygen, but, on the contrary, has still a very great affinity for that element,
and even attracts it from atmospheric air, immediately upon getting into
contact with it. This combination of nitrous gas with atmospheric air has
even become one of the methods for determining the quantity of oxygen
contained in air, and consequently for ascertaining its degree of salubrity.
This addition of oxygen converts the nitrous gas into a powerful acid, which
has a strong affinity with water, and which is itself susceptible of various
additional degrees of oxygenation. When the proportions of oxygen and
azote is below three parts, by weight, of the former, to one of the latter, the
acid is red coloured, and emits copious fumes. In this state, by the
application of a gentle heat, it gives out nitrous gas; and we term it, in this
degree of oxygenation, nitrous acid. When four parts, by weight, of oxygen,
are combined with one part of azote, the acid is clear and colourless, more
fixed in the fire than the nitrous acid, has less odour, and its constituent
elements are more firmly united. This species of acid, in conformity with
our principles of nomenclature, is called nitric acid.
Thus, nitric acid is the acid of nitre, surcharged with oxygen; nitrous acid is
the acid of nitre surcharged with azote; or, what is the same thing, with
nitrous gas; and this latter is azote not sufficiently saturated with oxygen to
possess the properties of an acid. To this degree of oxygenation, we have
afterwards, in the course of this work, given the generical name of oxyd[14].

FOOTNOTES:
[12] The term formerly used by the English chemists for this acid was written
sulphureous; but we have thought proper to spell it as above, that it may better
conform with the similar terminations of nitrous, carbonous, &c. to be used
hereafter. In general, we have used the English terminations ic and ous to

translate the terms of the Author which end with ique and cux, with hardly any
other alterations.—E.
[13] For this purpose, the operation called decrepitation is used, which consists
in subjecting it to nearly a red heat, in a proper vessel, so as to evaporate all its
water of crystallization.—E.
[14] In strict conformity with the principles of the new nomenclature, but which
the Author has given his reasons for deviating from in this instance, the
following ought to have been the terms for azote, in its several degrees of
oxygenation: Azote, azotic gas, (azote combined with caloric), azotic oxyd gas,
nitrous acid, and nitric acid.—E.

CHAP. VII.
Of the Decomposition of Oxygen Gas by means of Metals, and
the Formation of Metallic Oxyds.

Oxygen has a stronger affinity with metals heated to a certain degree than
with caloric; in consequence of which, all metallic bodies, excepting gold,
silver, and platina, have the property of decomposing oxygen gas, by
attracting its base from the caloric with which it was combined. We have
already shown in what manner this decomposition takes place, by means of
mercury and iron; having observed, that, in the case of the first, it must be
considered as a kind of gradual combustion, whilst, in the latter, the
combustion is extremely rapid, and attended with a brilliant flame. The use
of the heat employed in these operations is to separate the particles of the
metal from each other, and to diminish their attraction of cohesion or
aggregation, or, what is the same thing, their mutual attraction for each
other.
The absolute weight of metallic substances is augmented in proportion to
the quantity of oxygen they absorb; they, at the same time, lose their
metallic splendour, and are reduced into an earthy pulverulent matter. In this
state metals must not be considered as entirely saturated with oxygen,
because their action upon this element is counterbalanced by the power of
affinity between it and caloric. During the calcination of metals, the oxygen
is therefore acted upon by two separate and opposite powers, that of its
attraction for caloric, and that exerted by the metal, and only tends to unite
with the latter in consequence of the excess of the latter over the former,
which is, in general, very inconsiderable. Wherefore, when metallic
substances are oxygenated in atmospheric air, or in oxygen gas, they are not
converted into acids like sulphur, phosphorus, and charcoal, but are only
changed into intermediate substances, which, though approaching to the
nature of salts, have not acquired all the saline properties. The old chemists
have affixed the name of calx not only to metals in this state, but to every
body which has been long exposed to the action of fire without being

melted. They have converted this word calx into a generical term, under
which they confound calcareous earth, which, from a neutral salt, which it
really was before calcination, has been changed by fire into an earthy alkali,
by losing half of its weight, with metals which, by the same means, have
joined themselves to a new substance, whose quantity often exceeds half
their weight, and by which they have been changed almost into the nature
of acids. This mode of classifying substances of so very opposite natures,
under the same generic name, would have been quite contrary to our
principles of nomenclature, especially as, by retaining the above term for
this state of metallic substances, we must have conveyed very false ideas of
its nature. We have, therefore, laid aside the expression metallic calx
altogether, and have substituted in its place the term oxyd, from the Greek
word οξυς.
By this may be seen, that the language we have adopted is both copious and
expressive. The first or lowest degree of oxygenation in bodies, converts
them into oxyds; a second degree of additional oxygenation constitutes the
class of acids, of which the specific names, drawn from their particular
bases, terminate in ous, as the nitrous and sulphurous acids; the third degree
of oxygenation changes these into the species of acids distinguished by the
termination in ic, as the nitric and sulphuric acids; and, lastly, we can
express a fourth, or highest degree of oxygenation, by adding the word
oxygenated to the name of the acid, as has been already done with the
oxygenated muriatic acid.
We have not confined the term oxyd to expressing the combinations of
metals with oxygen, but have extended it to signify that first degree of
oxygenation in all bodies, which, without converting them into acids,
causes them to approach to the nature of salts. Thus, we give the name of
oxyd of sulphur to that soft substance into which sulphur is converted by
incipient combustion; and we call the yellow matter left by phosphorus,
after combustion, by the name of oxyd of phosphorus. In the same manner,
nitrous gas, which is azote in its first degree of oxygenation, is the oxyd of
azote. We have likewise oxyds in great numbers from the vegetable and
animal kingdoms; and I shall show, in the sequel, that this new language
throws great light upon all the operations of art and nature.

We have already observed, that almost all the metallic oxyds have peculiar
and permanent colours. These vary not only in the different species of
metals, but even according to the various degrees of oxygenation in the
same metal. Hence we are under the necessity of adding two epithets to
each oxyd, one of which indicates the metal oxydated[15], while the other
indicates the peculiar colour of the oxyd. Thus, we have the black oxyd of
iron, the red oxyd of iron, and the yellow oxyd of iron; which expressions
respectively answer to the old unmeaning terms of martial ethiops,
colcothar, and rust of iron, or ochre. We have likewise the gray, yellow, and
red oxyds of lead, which answer to the equally false or insignificant terms,
ashes of lead, massicot, and minium.
These denominations sometimes become rather long, especially when we
mean to indicate whether the metal has been oxydated in the air, by
detonation with nitre, or by means of acids; but then they always convey
just and accurate ideas of the corresponding object which we wish to
express by their use. All this will be rendered perfectly clear and distinct by
means of the tables which are added to this work.

FOOTNOTES:
[15] Here we see the word oxyd converted into the verb to oxydate, oxydated,
oxydating, after the same manner with the derivation of the verb to oxygenate,
oxygenated, oxygenating, from the word oxygen. I am not clear of the absolute
necessity of this second verb here first introduced, but think, in a work of this
nature, that it is the duty of the translator to neglect every other consideration for
the sake of strict fidelity to the ideas of his author.—E.

CHAP. VIII.
Of the Radical Principle of Water, and of its Decomposition by
Charcoal and Iron.

Until very lately, water has always been thought a simple substance,
insomuch that the older chemists considered it as an element. Such it
undoubtedly was to them, as they were unable to decompose it; or, at least,
since the decomposition which took place daily before their eyes was
entirely unnoticed. But we mean to prove, that water is by no means a
simple or elementary substance. I shall not here pretend to give the history
of this recent, and hitherto contested discovery, which is detailed in the
Memoirs of the Academy for 1781, but shall only bring forwards the
principal proofs of the decomposition and composition of water; and, I may
venture to say, that these will be convincing to such as consider them
impartially.

Experiment First.

Having fixed the glass tube EF, (Pl. vii. fig. 11.) of from 8 to 12 lines
diameter, across a furnace, with a small inclination from E to F, lute the
superior extremity E to the glass retort A, containing a determinate quantity
of distilled water, and to the inferior extremity F, the worm SS fixed into the
neck of the doubly tubulated bottle H, which has the bent tube KK adapted
to one of its openings, in such a manner as to convey such aëriform fluids
or gasses as may be disengaged, during the experiment, into a proper
apparatus for determining their quantity and nature.
To render the success of this experiment certain, it is necessary that the tube
EF be made of well annealed and difficultly fusible glass, and that it be
coated with a lute composed of clay mixed with powdered stone-ware;
besides which, it must be supported about its middle by means of an iron
bar passed through the furnace, lest it should soften and bend during the
experiment. A tube of China-ware, or porcellain, would answer better than

one of glass for this experiment, were it not difficult to procure one so
entirely free from pores as to prevent the passage of air or of vapours.
When things are thus arranged, a fire is lighted in the furnace EFCD, which
is supported of such a strength as to keep the tube EF red hot, but not to
make it melt; and, at the same time, such a fire is kept up in the furnace
VVXX, as to keep the water in the retort A continually boiling.
In proportion as the water in the retort A is evaporated, it fills the tube EF,
and drives out the air it contained by the tube KK; the aqueous gas formed
by evaporation is condensed by cooling in the worm SS, and falls, drop by
drop, into the tubulated bottle H. Having continued this operation until all
the water be evaporated from the retort, and having carefully emptied all the
vessels employed, we find that a quantity of water has passed over into the
bottle H, exactly equal to what was before contained in the retort A, without
any disengagement of gas whatsoever: So that this experiment turns out to
be a simple distillation; and the result would have been exactly the same, if
the water had been run from one vessel into the other, through the tube EF,
without having undergone the intermediate incandescence.

Experiment Second.

The apparatus being disposed, as in the former experiment, 28 grs. of
charcoal, broken into moderately small parts, and which has previously
been exposed for a long time to a red heat in close vessels, are introduced
into the tube EF. Every thing else is managed as in the preceding
experiment.
The water contained in the retort A is distilled, as in the former experiment,
and, being condensed in the worm, falls into the bottle H; but, at the same
time, a considerable quantity of gas is disengaged, which, escaping by the
tube KK, is received in a convenient apparatus for that purpose. After the
operation is finished, we find nothing but a few atoms of ashes remaining in
the tube EF; the 28 grs. of charcoal having entirely disappeared.
When the disengaged gasses are carefully examined, they are sound to
weigh 113.7 grs.[16]; these are of two kinds, viz. 144 cubical inches of
carbonic acid gas, weighing 100 grs. and 380 cubical inches of a very light

gas, weighing only 13.7 grs. which takes fire when in contact with air, by
the approach of a lighted body; and, when the water which has passed over
into the bottle H is carefully examined, it is found to have lost 85.7 grs. of
its weight. Thus, in this experiment, 85.7 grs. of water, joined to 28 grs. of
charcoal, have combined in such a way as to form 100 grs. of carbonic acid,
and 13.7 grs. of a particular gas capable of being burnt.
I have already shown, that 100 grs. of carbonic acid gas consists of 72 grs.
of oxygen, combined with 28 grs. of charcoal; hence the 28 grs. of charcoal
placed in the glass tube have acquired 72 grs. of oxygen from the water;
and it follows, that 85.7 grs. of water are composed of 72 grs. of oxygen,
combined with 13.7 grs. of a gas susceptible of combustion. We shall see
presently that this gas cannot possibly have been disengaged from the
charcoal, and must, consequently, have been produced from the water.
I have suppressed some circumstances in the above account of this
experiment, which would only have complicated and obscured its results in
the minds of the reader. For instance, the inflammable gas dissolves a very
small part of the charcoal, by which means its weight is somewhat
augmented, and that of the carbonic gas proportionally diminished. Altho'
the alteration produced by this circumstance is very inconsiderable; yet I
have thought it necessary to determine its effects by rigid calculation, and to
report, as above, the results of the experiment in its simplified state, as if
this circumstance had not happened. At any rate, should any doubts remain
respecting the consequences I have drawn from this experiment, they will
be fully dissipated by the following experiments, which I am going to
adduce in support of my opinion.

Experiment Third.

The apparatus being disposed exactly as in the former experiment, with this
difference, that instead of the 28 grs. of charcoal, the tube EF is filled with
274 grs. of soft iron in thin plates, rolled up spirally. The tube is made red
hot by means of its furnace, and the water in the retort A is kept constantly
boiling till it be all evaporated, and has passed through the tube EF, so as to
be condensed in the bottle H.

No carbonic acid gas is disengaged in this experiment, instead of which we
obtain 416 cubical inches, or 15 grs. of inflammable gas, thirteen times
lighter than atmospheric air. By examining the water which has been
distilled, it is found to have lost 100 grs. and the 274 grs. of iron confined
in the tube are found to have acquired 85 grs. additional weight, and its
magnitude is considerably augmented. The iron is now hardly at all
attractable by the magnet; it dissolves in acids without effervescence; and,
in short, it is converted into a black oxyd, precisely similar to that which
has been burnt in oxygen gas.
In this experiment we have a true oxydation of iron, by means of water,
exactly similar to that produced in air by the assistance of heat. One
hundred grains of water having been decomposed, 85 grs. of oxygen have
combined with the iron, so as to convert it into the state of black oxyd, and
15 grs. of a peculiar inflammable gas are disengaged: From all this it
clearly follows, that water is composed of oxygen combined with the base
of an inflammable gas, in the respective proportions of 85 parts, by weight
of the former, to 15 parts of the latter.
Thus water, besides the oxygen, which is one of its elements in common
with many other substances, contains another element as its constituent base
or radical, and for which we must find an appropriate term. None that we
could think of seemed better adapted than the word hydrogen, which
signifies the generative principle of water, from υδορ aqua, and γεινομας
gignor[17]. We call the combination of this element with caloric hydrogen
gas; and the term hydrogen expresses the base of that gas, or the radical of
water.
This experiment furnishes us with a new combustible body, or, in other
words, a body which has so much affinity with oxygen as to draw it from its
connection with caloric, and to decompose air or oxygen gas. This
combustible body has itself so great affinity with caloric, that, unless when
engaged in a combination with some other body, it always subsists in the
aëriform or gasseous state, in the usual temperature and pressure of our
atmosphere. In this state of gas it is about 1/13 of the weight of an equal
bulk of atmospheric air; it is not absorbed by water, though it is capable of
holding a small quantity of that fluid in solution, and it is incapable of being
used for respiration.

As the property this gas possesses, in common with all other combustible
bodies, is nothing more than the power of decomposing air, and carrying off
its oxygen from the caloric with which it was combined, it is easily
understood that it cannot burn, unless in contact with air or oxygen gas.
Hence, when we set fire to a bottle full of this gas, it burns gently, first at
the neck of the bottle, and then in the inside of it, in proportion as the
external air gets in: This combustion is slow and successive, and only takes
place at the surface of contact between the two gasses. It is quite different
when the two gasses are mixed before they are set on fire: If, for instance,
after having introduced one part of oxygen gas into a narrow mouthed
bottle, we fill it up with two parts of hydrogen gas, and bring a lighted
taper, or other burning body, to the mouth of the bottle, the combustion of
the two gasses takes place instantaneously with a violent explosion. This
experiment ought only to be made in a bottle of very strong green glass,
holding not more than a pint, and wrapped round with twine, otherwise the
operator will be exposed to great danger from the rupture of the bottle, of
which the fragments will be thrown about with great force.
If all that has been related above, concerning the decomposition of water, be
exactly conformable to truth;—if, as I have endeavoured to prove, that
substance be really composed of hydrogen, as its proper constituent
element, combined with oxygen, it ought to follow, that, by reuniting these
two elements together, we should recompose water; and that this actually
happens may be judged of by the following experiment.

Experiment Fourth.

I took a large cristal baloon, A, Pl. iv. fig. 5. holding about 30 pints, having
a large opening, to which was cemented the plate of copper BC, pierced
with four holes, in which four tubes terminate. The first tube, H h, is
intended to be adapted to an air pump, by which the baloon is to be
exhausted of its air. The second tube gg, communicates, by its extremity
MM, with a reservoir of oxygen gas, with which the baloon is to be filled.
The third tube d D d', communicates, by its extremity d NN, with a
reservoir of hydrogen gas. The extremity d' of this tube terminates in a
capillary opening, through which the hydrogen gas contained in the
reservoir is forced, with a moderate degree of quickness, by the pressure of

one or two inches of water. The fourth tube contains a metallic wire GL,
having a knob at its extremity L, intended for giving an electrical spark
from L to d', on purpose to set fire to the hydrogen gas: This wire is
moveable in the tube, that we may be able to separate the knob L from the
extremity d' of the tube D d'. The three tubes d D d', gg, and H h, are all
provided with stop-cocks.
That the hydrogen gas and oxygen gas may be as much as possible deprived
of water, they are made to pass, in their way to the baloon A, through the
tubes MM, NN, of about an inch diameter, and filled with salts, which, from
their deliquescent nature, greedily attract the moisture of the air: Such are
the acetite of potash, and the muriat or nitrat of lime[18]. These salts must
only be reduced to a coarse powder, lest they run into lumps, and prevent
the gasses from geting through their interstices.
We must be provided before hand with a sufficient quantity of oxygen gas,
carefully purified from all admixture of carbonic acid, by long contact with
a solution of potash[19].
We must likewise have a double quantity of hydrogen gas, carefully
purified in the same manner by long contact with a solution of potash in
water. The best way of obtaining this gas free from mixture is, by
decomposing water with very pure soft iron, as directed in Exp. 3. of this
chapter.
Having adjusted every thing properly, as above directed, the tube H h is
adapted to an air-pump, and the baloon A is exhausted of its air. We next
admit the oxygen gas so as to fill the baloon, and then, by means of
pressure, as is before mentioned, force a small stream of hydrogen gas
through its tube D d', which we immediately set on fire by an electric spark.
By means of the above described apparatus, we can continue the mutual
combustion of these two gasses for a long time, as we have the power of
supplying them to the baloon from their reservoirs, in proportion as they are
consumed. I have in another place[20] given a description of the apparatus
used in this experiment, and have explained the manner of ascertaining the
quantities of the gasses consumed with the most scrupulous exactitude.

In proportion to the advancement of the combustion, there is a deposition of
water upon the inner surface of the baloon or matrass A: The water
gradually increases in quantity, and, gathering into large drops, runs down
to the bottom of the vessel. It is easy to ascertain the quantity of water
collected, by weighing the baloon both before and after the experiment.
Thus we have a twofold verification of our experiment, by ascertaining both
the quantities of the gasses employed, and of the water formed by their
combustion: These two quantities must be equal to each other. By an
operation of this kind, Mr Meusnier and I ascertained that it required 85
parts, by weight, of oxygen, united to 15 parts of hydrogen, to compose 100
parts of water. This experiment, which has not hitherto been published, was
made in presence of a numerous committee from the Royal Academy. We
exerted the most scrupulous attention to its accuracy; and have reason to
believe that the above propositions cannot vary a two hundredth part from
absolute truth.
From these experiments, both analytical and synthetic, we may now affirm
that we have ascertained, with as much certainty as is possible in physical
or chemical subjects, that water is not a simple elementary substance, but is
composed of two elements, oxygen and hydrogen; which elements, when
existing separately, have so strong affinity for caloric, as only to subsist
under the form of gas in the common temperature and pressure of our
atmosphere.
This decomposition and recomposition of water is perpetually operating
before our eyes, in the temperature of the atmosphere, by means of
compound elective attraction. We shall presently see that the phenomena
attendant upon vinous fermentation, putrefaction, and even vegetation, are
produced, at least in a certain degree, by decomposition of water. It is very
extraordinary that this fact should have hitherto been overlooked by natural
philosophers and chemists: Indeed, it strongly proves, that, in chemistry, as
in moral philosophy, it is extremely difficult to overcome prejudices
imbibed in early education, and to search for truth in any other road than the
one we have been accustomed to follow.
I shall finish this chapter by an experiment much less demonstrative than
those already related, but which has appeared to make more impression
than any other upon the minds of many people. When 16 ounces of alkohol

are burnt in an apparatus[21] properly adapted for collecting all the water
disengaged during the combustion, we obtain from 17 to 18 ounces of
water. As no substance can furnish a product larger than its original bulk, it
follows, that something else has united with the alkohol during its
combustion; and I have already shown that this must be oxygen, or the base
of air. Thus alkohol contains hydrogen, which is one of the elements of
water; and the atmospheric air contains oxygen, which is the other element
necessary to the composition of water. This experiment is a new proof that
water is a compound substance.

FOOTNOTES:
[16] In the latter part of this work will be found a particular account of the
processes necessary for separating the different kinds of gasses, and for
determining their quantities.—A.
[17] This expression Hydrogen has been very severely criticised by some, who
pretend that it signifies engendered by water, and not that which engenders
water. The experiments related in this chapter prove, that, when water is
decomposed, hydrogen is produced, and that, when hydrogen is combined with
oxygen, water is produced: So that we may say, with equal truth, that water is
produced from hydrogen, or hydrogen is produced from water.—A.
[18] See the nature of these salts in the second part of this book.—A.
[19] By potash is here meant, pure or caustic alkali, deprived of carbonic acid by
means of quick-lime: In general, we may observe here, that all the alkalies and
earths must invariably be considered as in their pure or caustic state, unless
otherwise expressed.—E. The method of obtaining this pure alkali of potash will
be given in the sequel.—A.
[20] See the third part of this work.—A.
[21] See an account of this apparatus in the third part of this work.—A.

CHAP. IX.
Of the quantities of Caloric disengaged from different species of
Combustion.

We have already mentioned, that, when any body is burnt in the center of a
hollow sphere of ice and supplied with air at the temperature of zero (32°),
the quantity of ice melted from the inside of the sphere becomes a measure
of the relative quantities of caloric disengaged. Mr de la Place and I gave a
description of the apparatus employed for this kind of experiment in the
Memoirs of the Academy for 1780, p. 355; and a description and plate of
the same apparatus will be found in the third part of this work. With this
apparatus, phosphorus, charcoal, and hydrogen gas, gave the following
results:
One pound of phosphorus melted 100 libs. of ice.
One pound of charcoal melted 96 libs. 8 oz.
One pound of hydrogen gas melted 295 libs. 9 oz. 3-1/2 gros.
As a concrete acid is formed by the combustion of phosphorus, it is
probable that very little caloric remains in the acid, and, consequently, that
the above experiment gives us very nearly the whole quantity of caloric
contained in the oxygen gas. Even if we suppose the phosphoric acid to
contain a good deal of caloric, yet, as the phosphorus must have contained
nearly an equal quantity before combustion, the error must be very small, as
it will only consist of the difference between what was contained in the
phosphorus before, and in the phosphoric acid after combustion.
I have already shown in Chap. V. that one pound of phosphorus absorbs one
pound eight ounces of oxygen during combustion; and since, by the same
operation, 100 lib. of ice are melted, it follows, that the quantity of caloric
contained in one pound of oxygen gas is capable of melting 66 libs. 10 oz. 5
gros 24 grs. of ice.

One pound of charcoal during combustion melts only 96 libs. 8 oz. of ice,
whilst it absorbs 2 libs. 9 oz. 1 gros 10 grs. of oxygen. By the experiment
with phosphorus, this quantity of oxygen gas ought to disengage a quantity
of caloric sufficient to melt 171 libs. 6 oz. 5 gros of ice; consequently,
during this experiment, a quantity of caloric, sufficient to melt 74 libs. 14
oz. 5 gros of ice disappears. Carbonic acid is not, like phosphoric acid, in a
concrete state after combustion but in the state of gas, and requires to be
united with caloric to enable it to subsist in that state; the quantity of caloric
missing in the last experiment is evidently employed for that purpose. When
we divide that quantity by the weight of carbonic acid, formed by the
combustion of one pound of charcoal, we find that the quantity of caloric
necessary for changing one pound of carbonic acid from the concrete to the
gasseous state, would be capable of melting 20 libs. 15 oz. 5 gros of ice.
We may make a similar calculation with the combustion of hydrogen gas
and the consequent formation of water. During the combustion of one
pound of hydrogen gas, 5 libs. 10 oz. 5 gros 24 grs. of oxygen gas are
absorbed, and 295 libs. 9 oz. 3-1/2 gros of ice are melted. But 5 libs. 10 oz.
5 gros 24 grs. of oxygen gas, in changing from the aëriform to the solid
state, loses, according to the experiment with phosphorus, enough of caloric
to have melted 377 libs. 12 oz. 3 gros of ice. There is only disengaged, from
the same quantity of oxygen, during its combustion with hydrogen gas, as
much caloric as melts 295 libs. 2 oz. 3-1/2 gros; wherefore there remains in
the water at Zero (32°), formed, during this experiment, as much caloric as
would melt 82 libs. 9 oz. 7-1/2 gros of ice.
Hence, as 6 libs. 10 oz. 5 gros 24 grs. of water are formed from the
combustion of one pound of hydrogen gas with 5 libs. 10 oz. 5 gros 24 grs.
of oxygen, it follows that, in each pound of water, at the temperature of
Zero, (32°), there exists as much caloric as would melt 12 libs. 5 oz. 2 gros
48 grs. of ice, without taking into account the quantity originally contained
in the hydrogen gas, which we have been obliged to omit, for want of data
to calculate its quantity. From this it appears that water, even in the state of
ice, contains a considerable quantity of caloric, and that oxygen, in entering
into that combination, retains likewise a good proportion.
From these experiments, we may assume the following results as
sufficiently established.

Combustion of Phosphorus.

From the combustion of phosphorus, as related in the foregoing
experiments, it appears, that one pound of phosphorus requires 1 lib. 8 oz.
of oxygen gas for its combustion, and that 2 libs. 8 oz. of concrete
phosphoric acid are produced.

The quantity of caloric disengaged by the combustion of one
pound of phosphorus, expressed by the number of pounds of 100.00000.
ice melted during that operation, is
The quantity disengaged from each pound of oxygen, during
the combustion of phosphorus, expressed in the same manner, 66.66667.
is
The quantity disengaged during the formation of one pound of
40.00000.
phosphoric acid,
The quantity remaining in each pound of phosphoric acid, 0.00000(A).

[Note A: We here suppose the phosphoric acid not to contain any caloric,
which is not strictly true; but, as I have before observed, the quantity it
really contains is probably very small, and we have not given it a value, for
want of a sufficient data to go upon.—A.]

Combustion of Charcoal.

In the combustion of one pound of charcoal, 2 libs. 9 oz. 1 gros 10 grs. of
oxygen gas are absorbed, and 3 libs. 9 oz. 1 gros 10 grs. of carbonic acid
gas are formed.

Caloric, disengaged daring the combustion of one pound of
96.50000(A).
charcoal,
Caloric disengaged during the combustion of charcoal, from
37.52823.
each pound of oxygen gas absorbed,
Caloric disengaged during the formation of one pound of
27.02024.
carbonic acid gas,
Caloric retained by each pound of oxygen after the
29.13844.
combustion,

Caloric necessary for supporting one pound of carbonic acid
20.97960.
in the state of gas,

[Note A: All these relative quantities of caloric are expressed by the number
of pounds of ice, and decimal parts, melted during the several operations.—
E.]

Combustion of Hydrogen Gas.

In the combustion of one pound of hydrogen gas, 5 libs. 10 oz. 5 gros 24
grs. of oxygen gas are absorbed, and 6 libs. 10 oz. 5 gros 24 grs. of water
are formed.

Caloric from each lib. of hydrogen gas, 295.58950.
Caloric from each lib. of oxygen gas, 52.16280.
Caloric disengaged during the formation of each pound of
44.33840.
water,
Caloric retained by each lib. of oxygen after combustion with
14.50386.
hydrogen,
Caloric retained by each lib. of water at the temperature of
12.32823.
Zero (32°),

Of the Formation of Nitric Acid.

When we combine nitrous gas with oxygen gas, so as to form nitric or
nitrous acid a degree of heat is produced, which is much less considerable
than what is evolved during the other combinations of oxygen; whence it
follows that oxygen, when it becomes fixed in nitric acid, retains a great
part of the heat which it possessed in the state of gas. It is certainly possible
to determine the quantity of caloric which is disengaged during the
combination of these two gasses, and consequently to determine what
quantity remains after the combination takes place. The first of these
quantities might be ascertained, by making the combination of the two
gasses in an apparatus surrounded by ice; but, as the quantity of caloric
disengaged is very inconsiderable, it would be necessary to operate upon a
large quantity of the two gasses in a very troublesome and complicated

apparatus. By this consideration, Mr de la Place and I have hitherto been
prevented from making the attempt. In the mean time, the place of such an
experiment may be supplied by calculations, the results of which cannot be
very far from truth.
Mr de la Place and I deflagrated a convenient quantity of nitre and charcoal
in an ice apparatus, and found that twelve pounds of ice were melted by the
deflagration of one pound of nitre. We shall see, in the sequel, that one
pound of nitre is composed, as under, of

Potash 7 oz. 6 gros 51.84 grs. = 4515.84 grs.
Dry acid 8 1 21.16 = 4700.16.

The above quantity of dry acid is composed of

Oxygen 6 oz. 3 gros 66.34 grs. = 3738.34 grs.
Azote 1 5 25.82 = 961.82.

By this we find that, during the above deflagration, 2 gros 1-1/3 gr. of
charcoal have suffered combustion, alongst with 3738.34 grs. or 6 oz. 3
gros 66.34 grs. of oxygen. Hence, since 12 libs. of ice were melted during
the combustion, it follows, that one pound of oxygen burnt in the same
manner would have melted 29.58320 libs. of ice. To which the quantity of
caloric, retained by a pound of oxygen after combining with charcoal to
form carbonic acid gas, being added, which was already ascertained to be
capable of melting 29.13844 libs. of ice, we have for the total quantity of
caloric remaining in a pound of oxygen, when combined with nitrous gas in
the nitric acid 58.72164; which is the number of pounds of ice the caloric
remaining in the oxygen in that state is capable of melting.
We have before seen that, in the state of oxygen gas, it contained at least
66.66667; wherefore it follows that, in combining with azote to form nitric
acid, it only loses 7.94502. Farther experiments upon this subject are
necessary to ascertain how far the results of this calculation may agree with
direct fact. This enormous quantity of caloric retained by oxygen in its
combination into nitric acid, explains the cause of the great disengagement
of caloric during the deflagrations of nitre; or, more strictly speaking, upon
all occasions of the decomposition of nitric acid.

Of the Combustion of Wax.

Having examined several cases of simple combustion, I mean now to give a
few examples of a more complex nature. One pound of wax-taper being
allowed to burn slowly in an ice apparatus, melted 133 libs. 2 oz. 5-1/3 gros
of ice. According to my experiments in the Memoirs of the Academy for
1784, p. 606, one pound of wax-taper consists of 13 oz. 1 gros 23 grs. of
charcoal, and 2 oz. 6 gros 49 grs. of hydrogen.

By the foregoing experiments, the above quantity of 79.39390 libs. of
charcoal ought to melt ice;
and the hydrogen should melt 52.37605
————
In all 131.76995 libs.

Thus, we see the quantity of caloric disengaged from a burning taper, is
pretty exactly conformable to what was obtained by burning separately a
quantity of charcoal and hydrogen equal to what enters into its composition.
These experiments with the taper were several times repeated, so that I have
reason to believe them accurate.

Combustion of Olive Oil.

We included a burning lamp, containing a determinate quantity of olive-oil,
in the ordinary apparatus, and, when the experiment was finished, we
ascertained exactly the quantities of oil consumed, and of ice melted; the
result was, that, during the combustion of one pound of olive-oil, 148 libs.
14 oz. 1 gros of ice were melted. By my experiments in the Memoirs of the
Academy for 1784, and of which the following Chapter contains an
abstract, it appears that one pound of olive-oil consists of 12 oz. 5 gros 5
grs. of charcoal, and 3 oz. 2 gros 67 grs. of hydrogen. By the foregoing
experiments, that quantity of charcoal should melt 76.18723 libs. of ice, and
the quantity of hydrogen in a pound of the oil should melt 62.15053 libs.
The sum of these two gives 138.33776 libs. of ice, which the two
constituent elements of the oil would have melted, had they separately
suffered combustion, whereas the oil really melted 148.88330 libs. which

gives an excess of 10.54554 in the result of the experiment above the
calculated result, from data furnished by former experiments.
This difference, which is by no means very considerable, may arise from
errors which are unavoidable in experiments of this nature, or it may be
owing to the composition of oil not being as yet exactly ascertained. It
proves, however, that there is a great agreement between the results of our
experiments, respecting the combination of caloric, and those which regard
its disengagement.
The following desiderata still remain to be determined, viz. What quantity
of caloric is retained by oxygen, after combining with metals, so as to
convert them into oxyds; What quantity is contained by hydrogen, in its
different states of existence; and to ascertain, with more precision than is
hitherto attained, how much caloric is disengaged during the formation of
water, as there still remain considerable doubts with respect to our present
determination of this point, which can only be removed by farther
experiments. We are at present occupied with this inquiry; and, when once
these several points are well ascertained, which we hope they will soon be,
we shall probably be under the necessity of making considerable
corrections upon most of the results of the experiments and calculations in
this Chapter. I did not, however, consider this as a sufficient reason for
withholding so much as is already known from such as may be inclined to
labour upon the same subject. It is difficult, in our endeavours to discover
the principles of a new science, to avoid beginning by guess-work; and it is
rarely possible to arrive at perfection from the first setting out.

CHAP. X.
Of the Combination of Combustible Substances with each other.

As combustible substances in general have a great affinity for oxygen, they
ought likewise to attract, or tend to combine with each other; quae sunt
eadem uni tertio, sunt eadem inter se; and the axiom is found to be true.
Almost all the metals, for instance, are capable of uniting with each other,
and forming what are called alloys[22], in common language. Most of these,
like all combinations, are susceptible of several degrees of saturation; the
greater number of these alloys are more brittle than the pure metals of
which they are composed, especially when the metals alloyed together are
considerably different in their degrees of fusibility. To this difference in
fusibility, part of the phenomena attendant upon alloyage are owing,
particularly the property of iron, called by workmen hotshort. This kind of
iron must be considered as an alloy, or mixture of pure iron, which is almost
infusible, with a small portion of some other metal which fuses in a much
lower degree of heat. So long as this alloy remains cold, and both metals are
in the solid state, the mixture is malleable; but, if heated to a sufficient
degree to liquify the more fusible metal, the particles of the liquid metal,
which are interposed between the particles of the metal remaining solid,
must destroy their continuity, and occasion the alloy to become brittle. The
alloys of mercury, with the other metals, have usually been called
amalgams, and we see no inconvenience from continuing the use of that
term.
Sulphur, phosphorus, and charcoal, readily unite with metals. Combinations
of sulphur with metals are usually named pyrites. Their combinations with
phosphorus and charcoal are either not yet named, or have received new
names only of late; so that we have not scrupled to change them according
to our principles. The combinations of metal and sulphur we call sulphurets,
those with phosphorus phosphurets, and those formed with charcoal
carburets. These denominations are extended to all the combinations into
which the above three substances enter, without being previously

oxygenated. Thus, the combination of sulphur with potash, or fixed
vegetable alkali, is called sulphuret of potash; that which it forms with
ammoniac, or volatile alkali, is termed sulphuret of ammoniac.
Hydrogen is likewise capable of combining with many combustible
substances. In the state of gas, it dissolves charcoal, sulphur, phosphorus,
and several metals; we distinguish these combinations by the terms,
carbonated hydrogen gas, sulphurated hydrogen gas, and phosphorated
hydrogen gas. The sulphurated hydrogen gas was called hepatic air by
former chemists, or foetid air from sulphur, by Mr Scheele. The virtues of
several mineral waters, and the foetid smell of animal excrements, chiefly
arise from the presence of this gas. The phosphorated hydrogen gas is
remarkable for the property, discovered by Mr Gengembre, of taking fire
spontaneously upon getting into contact with atmospheric air, or, what is
better, with oxygen gas. This gas has a strong flavour, resembling that of
putrid fish; and it is very probable that the phosphorescent quality of fish, in
the state of putrefaction, arises from the escape of this species of gas. When
hydrogen and charcoal are combined together, without the intervention of
caloric, to bring the hydrogen into the state of gas, they form oil, which is
either fixed or volatile, according to the proportions of hydrogen and
charcoal in its composition. The chief difference between fixed or fat oils
drawn from vegetables by expression, and volatile or essential oils, is, that
the former contains an excess of charcoal, which is separated when the oils
are heated above the degree of boiling water; whereas the volatile oils,
containing a just proportion of these two constituent ingredients, are not
liable to be decomposed by that heat, but, uniting with caloric into the
gasseous state, pass over in distillation unchanged.
In the Memoirs of the Academy for 1784, p. 593. I gave an account of my
experiments upon the composition of oil and alkohol, by the union of
hydrogen with charcoal, and of their combination with oxygen. By these
experiments, it appears that fixed oils combine with oxygen during
combustion, and are thereby converted into water and carbonic acid. By
means of calculation applied to the products of these experiments, we find
that fixed oil is composed of 21 parts, by weight, of hydrogen combined
with 79 parts of charcoal. Perhaps the solid substances of an oily nature,
such as wax, contain a proportion of oxygen, to which they owe their state

of solidity. I am at present engaged in a series of experiments, which I hope
will throw great light upon this subject.
It is worthy of being examined, whether hydrogen in its concrete state,
uncombined with caloric, be susceptible of combination with sulphur,
phosphorus, and the metals. There is nothing that we know of, which, a
priori, should render these combinations impossible; for combustible bodies
being in general susceptible of combination with each other, there is no
evident reason for hydrogen being an exception to the rule: However, no
direct experiment as yet establishes either the possibility or impossibility of
this union. Iron and zinc are the most likely, of all the metals, for entering
into combination with hydrogen; but, as these have the property of
decomposing water, and as it is very difficult to get entirely free from
moisture in chemical experiments, it is hardly possible to determine
whether the small portions of hydrogen gas, obtained in certain experiments
with these metals, were previously combined with the metal in the state of
solid hydrogen, or if they were produced by the decomposition of a minute
quantity of water. The more care we take to prevent the presence of water in
these experiments, the less is the quantity of hydrogen gas procured; and,
when very accurate precautions are employed, even that quantity becomes
hardly sensible.
However this inquiry may turn out respecting the power of combustible
bodies, as sulphur, phosphorus, and metals, to absorb hydrogen, we are
certain that they only absorb a very small portion; and that this
combination, instead of being essential to their constitution, can only be
considered as a foreign substance, which contaminates their purity. It is the
province of the advocates[23] for this system to prove, by decisive
experiments, the real existence of this combined hydrogen, which they have
hitherto only done by conjectures founded upon suppositions.

FOOTNOTES:
[22] This term alloy, which we have from the language of the arts, serves
exceedingly well for distinguishing all the combinations or intimate unions of
metals with each other, and is adopted in our new nomenclature for that purpose.
—A.

[23] By these are meant the supporters of the phlogistic theory, who at present
consider hydrogen, or the base of inflammable air, as the phlogiston of the
celebrated Stahl.—E.

CHAP. XI.
Observations upon Oxyds and Acids with several Bases—and
upon the Composition of Animal and Vegetable Substances.

We have, in Chap. V. and VIII. examined the products resulting from the
combustion of the four simple combustible substances, sulphur,
phosphorus, charcoal, and hydrogen: We have shown, in Chap. X that the
simple combustible substances are capable of combining with each other
into compound combustible substances, and have observed that oils in
general, and particularly the fixed vegetable oils, belong to this class, being
composed of hydrogen and charcoal. It remains, in this chapter, to treat of
the oxygenation of these compound combustible substances, and to show
that there exist acids and oxyds having double and triple bases. Nature
furnishes us with numerous examples of this kind of combinations, by
means of which, chiefly, she is enabled to produce a vast variety of
compounds from a very limited number of elements, or simple substances.
It was long ago well known, that, when muriatic and nitric acids were
mixed together, a compound acid was formed, having properties quite
distinct from those of either of the acids taken separately. This acid was
called aqua regia, from its most celebrated property of dissolving gold,
called king of metals by the alchymists. Mr Berthollet has distinctly proved
that the peculiar properties of this acid arise from the combined action of its
two acidifiable bases; and for this reason we have judged it necessary to
distinguish it by an appropriate name: That of nitro-muriatic acid appears
extremely applicable, from its expressing the nature of the two substances
which enter into its composition.
This phenomenon of a double base in one acid, which had formerly been
observed only in the nitro-muriatic acid, occurs continually in the vegetable
kingdom, in which a simple acid, or one possessed of a single acidifiable
base, is very rarely found. Almost all the acids procurable from this
kingdom have bases composed of charcoal and hydrogen, or of charcoal,
hydrogen, and phosphorus, combined with more or less oxygen. All these

bases, whether double or triple, are likewise formed into oxyds, having less
oxygen than is necessary to give them the properties of acids. The acids and
oxyds from the animal kingdom are still more compound, as their bases
generally consist of a combination of charcoal, phosphorus, hydrogen, and
azote.
As it is but of late that I have acquired any clear and distinct notions of
these substances, I shall not, in this place, enlarge much upon the subject,
which I mean to treat of very fully in some memoirs I am preparing to lay
before the Academy. Most of my experiments are already performed; but, to
be able to give exact reports of the resulting quantities, it is necessary that
they be carefully repeated, and increased in number: Wherefore, I shall only
give a short enumeration of the vegetable and animal acids and oxyds, and
terminate this article by a few reflections upon the composition of vegetable
and animal bodies.
Sugar, mucus, under which term we include the different kinds of gums,
and starch, are vegetable oxyds, having hydrogen and charcoal combined,
in different proportions, as their radicals or bases, and united with oxygen,
so as to bring them to the state of oxyds. From the state of oxyds they are
capable of being changed into acids by the addition of a fresh quantity of
oxygen; and, according to the degrees of oxygenation, and the proportion of
hydrogen and charcoal in their bases, they form the several kinds of
vegetable acids.
It would be easy to apply the principles of our nomenclature to give names
to these vegetable acids and oxyds, by using the names of the two
substances which compose their bases: They would thus become hydro-
carbonous acids and oxyds: In this method we might indicate which of their
elements existed in excess, without circumlocution, after the manner used
by Mr Rouelle for naming vegetable extracts: He calls these extracto-
resinous when the extractive matter prevails in their composition, and
resino-extractive when they contain a larger proportion of resinous matter.
Upon that plan, and by varying the terminations according to the formerly
established rules of our nomenclature, we have the following
denominations: Hydro-carbonous, hydro-carbonic; carbono-hydrous, and
carbono-hydric oxyds. And for the acids: Hydro-carbonous, hydro carbonic,
oxygenated hydro-carbonic; carbono-hydrous, carbono-hydric, and

oxygenated carbono-hydric. It is probable that the above terms would
suffice for indicating all the varieties in nature, and that, in proportion as the
vegetable acids become well understood, they will naturally arrange
themselves under these denominations. But, though we know the elements
of which these are composed, we are as yet ignorant of the proportions of
these ingredients, and are still far from being able to class them in the above
methodical manner; wherefore, we have determined to retain the ancient
names provisionally. I am somewhat farther advanced in this inquiry than at
the time of publishing our conjunct essay upon chemical nomenclature; yet
it would be improper to draw decided consequences from experiments not
yet sufficiently precise: Though I acknowledge that this part of chemistry
still remains in some degree obscure, I must express my expectations of its
being very soon elucidated.
I am still more forcibly necessitated to follow the same plan in naming the
acids, which have three or four elements combined in their bases; of these
we have a considerable number from the animal kingdom, and some even
from vegetable substances. Azote, for instance, joined to hydrogen and
charcoal, form the base or radical of the Prussic acid; we have reason to
believe that the same happens with the base of the Gallic acid; and almost
all the animal acids have their bases composed of azote, phosphorus,
hydrogen, and charcoal. Were we to endeavour to express at once all these
four component parts of the bases, our nomenclature would undoubtedly be
methodical; it would have the property of being clear and determinate; but
this assemblage of Greek and Latin substantives and adjectives, which are
not yet universally admitted by chemists, would have the appearance of a
barbarous language, difficult both to pronounce and to be remembered.
Besides, this part of chemistry being still far from that accuracy it must
arrive to, the perfection of the science ought certainly to precede that of its
language; and we must still, for some time, retain the old names for the
animal oxyds and acids. We have only ventured to make a few slight
modifications of these names, by changing the termination into ous, when
we have reason to suppose the base to be in excess, and into ic, when we
suspect the oxygen predominates.
The following are all the vegetable acids hitherto known:

1. Acetous acid.

2. Acetic acid.
3. Oxalic acid.
4. Tartarous acid.
5. Pyro-tartarous acid.
6. Citric acid.
7. Malic acid.
8. Pyro-mucous acid.
9. Pyro-lignous acid.
10. Gallic acid.
11. Benzoic acid.
12. Camphoric acid.
13. Succinic acid.
Though all these acids, as has been already said, are chiefly, and almost
entirely, composed of hydrogen, charcoal, and oxygen, yet, properly
speaking, they contain neither water carbonic acid nor oil, but only the
elements necessary for forming these substances. The power of affinity
reciprocally exerted by the hydrogen, charcoal, and oxygen, in these acids,
is in a state of equilibrium only capable of existing in the ordinary
temperature of the atmosphere; for, when they are heated but a very little
above the temperature of boiling water, this equilibrium is destroyed, part of
the oxygen and hydrogen unite, and form water; part of the charcoal and
hydrogen combine into oil; part of the charcoal and oxygen unite to form
carbonic acid; and, lastly, there generally remains a small portion of
charcoal, which, being in excess with respect to the other ingredients, is left
free. I mean to explain this subject somewhat farther in the succeeding
chapter.
The oxyds of the animal kingdom are hitherto less known than those from
the vegetable kingdom, and their number is as yet not at all determined. The
red part of the blood, lymph, and most of the secretions, are true oxyds,
under which point of view it is very important to consider them. We are
only acquainted with six animal acids, several of which, it is probable,
approach very near each other in their nature, or, at least, differ only in a
scarcely sensible degree. I do not include the phosphoric acid amongst
these, because it is found in all the kingdoms of nature. They are,

1. Lactic acid.

2. Saccholactic acid.
3. Bombic acid.
4. Formic acid.
5. Sebacic acid.
6. Prussic acid.
The connection between the constituent elements of the animal oxyds and
acids is not more permanent than in those from the vegetable kingdom, as a
small increase of temperature is sufficient to overturn it. I hope to render
this subject more distinct than has been done hitherto in the following
chapter.

CHAP. XII.
Of the Decomposition of Vegetable and Animal Substances by the
Action of Fire.

Before we can thoroughly comprehend what takes place during the
decomposition of vegetable substances by fire, we must take into
consideration the nature of the elements which enter into their composition,
and the different affinities which the particles of these elements exert upon
each other, and the affinity which caloric possesses with them. The true
constituent elements of vegetables are hydrogen, oxygen, and charcoal:
These are common to all vegetables, and no vegetable can exist without
them: Such other substances as exist in particular vegetables are only
essential to the composition of those in which they are found, and do not
belong to vegetables in general.
Of these elements, hydrogen and oxygen have a strong tendency to unite
with caloric, and be converted into gas, whilst charcoal is a fixed element,
having but little affinity with caloric. On the other hand, oxygen, which, in
the usual temperature, tends nearly equally to unite with hydrogen and with
charcoal, has a much stronger affinity with charcoal when at the red
heat[24], and then unites with it to form carbonic acid.
Although we are far from being able to appreciate all these powers of
affinity, or to express their proportional energy by numbers, we are certain,
that, however variable they may be when considered in relation to the
quantity of caloric with which they are combined, they are all nearly in
equilibrium in the usual temperature of the atmosphere; hence vegetables
neither contain oil[25], water, nor carbonic acid, tho' they contain all the
elements of these substances. The hydrogen is neither combined with the
oxygen nor with the charcoal, and reciprocally; the particles of these three
substances form a triple combination, which remains in equilibrium whilst
undisturbed by caloric but a very slight increase of temperature is sufficient
to overturn this structure of combination.

If the increased temperature to which the vegetable is exposed does not
exceed the heat of boiling water, one part of the hydrogen combines with
the oxygen, and forms water, the rest of the hydrogen combines with a part
of the charcoal, and forms volatile oil, whilst the remainder of the charcoal,
being set free from its combination with the other elements, remains fixed
in the bottom of the distilling vessel.
When, on the contrary, we employ a red heat, no water is formed, or, at
least, any that may have been produced by the first application of the heat is
decomposed, the oxygen having a greater affinity with the charcoal at this
degree of heat, combines with it to form carbonic acid, and the hydrogen
being left free from combination with the other elements, unites with
caloric, and escapes in the state of hydrogen gas. In this high temperature,
either no oil is formed, or, if any was produced during the lower
temperature at the beginning of the experiment, it is decomposed by the
action of the red heat. Thus the decomposition of vegetable matter, under a
high temperature, is produced by the action of double and triple affinities;
while the charcoal attracts the oxygen, on purpose to form carbonic acid,
the caloric attracts the hydrogen, and converts it into hydrogen gas.
The distillation of every species of vegetable substance confirms the truth
of this theory, if we can give that name to a simple relation of facts. When
sugar is submitted to distillation, so long as we only employ a heat but a
little below that of boiling water, it only loses its water of cristallization, it
still remains sugar, and retains all its properties; but, immediately upon
raising the heat only a little above that degree, it becomes blackened, a part
of the charcoal separates from the combination, water slightly acidulated
passes over accompanied by a little oil, and the charcoal which remains in
the retort is nearly a third part of the original weight of the sugar.
The operation of affinities which take place during the decomposition, by
fire, of vegetables which contain azote, such as the cruciferous plants, and
of those containing phosphorus, is more complicated; but, as these
substances only enter into the composition of vegetables in very small
quantities, they only, apparently, produce slight changes upon the products
of distillation; the phosphorus seems to combine with the charcoal, and,
acquiring fixity from that union, remains behind in the retort, while the

azote, combining with a part of the hydrogen, forms ammoniac, or volatile
alkali.
Animal substances, being composed nearly of the same elements with
cruciferous plants, give the same products in distillation, with this
difference, that, as they contain a greater quantity of hydrogen and azote,
they produce more oil and more ammoniac. I shall only produce one fact as
a proof of the exactness with which this theory explains all the phenomena
which occur during the distillation of animal substances, which is the
rectification and total decomposition of volatile animal oil, commonly
known by the name of Dippel's oil. When these oils are procured by a first
distillation in a naked fire they are brown, from containing a little charcoal
almost in a free state; but they become quite colourless by rectification.
Even in this state the charcoal in their composition has so slight a
connection with the other elements as to separate by mere exposure to the
air. If we put a quantity of this animal oil, well rectified, and consequently
clear, limpid, and transparent, into a bell-glass filled with oxygen gas over
mercury, in a short time the gas is much diminished, being absorbed by the
oil, the oxygen combining with the hydrogen of the oil forms water, which
sinks to the bottom, at the same time the charcoal which was combined with
the hydrogen being set free, manifests itself by rendering the oil black.
Hence the only way of preserving these oils colourless and transparent, is
by keeping them in bottles perfectly full and accurately corked, to hinder
the contact of air, which always discolours them.
Successive rectifications of this oil furnish another phenomenon confirming
our theory. In each distillation a small quantity of charcoal remains in the
retort, and a little water is formed by the union of the oxygen contained in
the air of the distilling vessels with the hydrogen of the oil. As this takes
place in each successive distillation, if we make use of large vessels and a
considerable degree of heat, we at last decompose the whole of the oil, and
change it entirely into water and charcoal. When we use small vessels, and
especially when we employ a slow fire, or degree of heat little above that of
boiling water, the total decomposition of these oils, by repeated distillation,
is greatly more tedious, and more difficultly accomplished. I shall give a
particular detail to the Academy, in a separate memoir, of all my
experiments upon the decomposition of oil; but what I have related above

may suffice to give just ideas of the composition of animal and vegetable
substances, and of their decomposition by the action of fire.

FOOTNOTES:
[24] Though this term, red heat, does not indicate any absolutely determinate
degree of temperature, I shall use it sometimes to express a temperature
considerably above that of boiling water.—A.
[25] I must be understood here to speak of vegetables reduced to a perfectly dry
state; and, with respect to oil, I do not mean that which is procured by expression
either in the cold, or in a temperature not exceeding that of boiling water; I only
allude to the empyreumatic oil procured by distillation with a naked fire, in a
heat superior to the temperature of boiling water; which is the only oil declared
to be produced by the operation of fire. What I have published upon this subject
in the Memoirs of the Academy for 1786 may be consulted.—A.

CHAP. XIII.
Of the Decomposition of Vegetable Oxyds by the Vinous
Fermentation.

The manner in which wine, cyder, mead, and all the liquors formed by the
spiritous fermentation, are produced, is well known to every one. The juice
of grapes or of apples being expressed, and the latter being diluted with
water, they are put into large vats, which are kept in a temperature of at
least 10° (54.5°) of the thermometer. A rapid intestine motion, or
fermentation, very soon takes place, numerous globules of gas form in the
liquid and burst at the surface; when the fermentation is at its height, the
quantity of gas disengaged is so great as to make the liquor appear as if
boiling violently over a fire. When this gas is carefully gathered, it is found
to be carbonic acid perfectly pure, and free from admixture with any other
species of air or gas whatever.
When the fermentation is completed, the juice of grapes is changed from
being sweet, and full of sugar, into a vinous liquor which no longer contains
any sugar, and from which we procure, by distillation, an inflammable
liquor, known in commerce under the name of Spirit of Wine. As this liquor
is produced by the fermentation of any saccharine matter whatever diluted
with water, it must have been contrary to the principles of our nomenclature
to call it spirit of wine rather than spirit of cyder, or of fermented sugar;
wherefore, we have adopted a more general term, and the Arabic word
alkohol seems extremely proper for the purpose.
This operation is one of the most extraordinary in chemistry: We must
examine whence proceed the disengaged carbonic acid and the inflammable
liquor produced, and in what manner a sweet vegetable oxyd becomes thus
converted into two such opposite substances, whereof one is combustible,
and the other eminently the contrary. To solve these two questions, it is
necessary to be previously acquainted with the analysis of the fermentable
substance, and of the products of the fermentation. We may lay it down as
an incontestible axiom, that, in all the operations of art and nature, nothing

is created; an equal quantity of matter exists both before and after the
experiment; the quality and quantity of the elements remain precisely the
same; and nothing takes place beyond changes and modifications in the
combination of these elements. Upon this principle the whole art of
performing chemical experiments depends: We must always suppose an
exact equality between the elements of the body examined and those of the
products of its analysis.
Hence, since from must of grapes we procure alkohol and carbonic acid, I
have an undoubted right to suppose that must consists of carbonic acid and
alkohol. From these premises, we have two methods of ascertaining what
passes during vinous fermentation, by determining the nature of, and the
elements which compose, the fermentable substances, or by accurately
examining the produces resulting from fermentation; and it is evident that
the knowledge of either of these must lead to accurate conclusions
concerning the nature and composition of the other. From these
considerations, it became necessary accurately to determine the constituent
elements of the fermentable substances; and, for this purpose, I did not
make use of the compound juices of fruits, the rigorous analysis of which is
perhaps impossible, but made choice of sugar, which is easily analysed, and
the nature of which I have already explained. This substance is a true
vegetable oxyd with two bases, composed of hydrogen and charcoal
brought to the state of an oxyd, by a certain proportion of oxygen; and these
three elements are combined in such a way, that a very slight force is
sufficient to destroy the equilibrium of their connection. By a long train of
experiments, made in various ways, and often repeated, I ascertained that
the proportion in which these ingredients exist in sugar, are nearly eight
parts of hydrogen, 64 parts of oxygen, and 28 parts of charcoal, all by
weight, forming 100 parts of sugar.
Sugar must be mixed with about four times its weight of water, to render it
susceptible of fermentation; and even then the equilibrium of its elements
would remain undisturbed, without the assistance of some substance, to
give a commencement to the fermentation. This is accomplished by means
of a little yeast from beer; and, when the fermentation is once excited, it
continues of itself until completed. I shall, in another place, give an account
of the effects of yeast, and other ferments, upon fermentable substances. I
have usually employed 10 libs. of yeast, in the state of paste, for each 100

libs. of sugar, with as much water as is four times the weight of the sugar. I
shall give the results of my experiments exactly as they were obtained,
preserving even the fractions produced by calculation.

Table I. Materials of Fermentation.

libs. oz. gros grs.
Water 400 0 0 0
Sugar 100 0 0 0
Yeast in paste, 10 libs. composed of { Water 7 3 6 44
{ Dry yeast 2 12 1 28
—————— ——
Total 510

Table II. Constituent Elements of the Materials of Fermentation.

libs. oz. gros grs.

407 libs, 3 oz. 6 gros 44 grs. of
{Hydrogen 61 1 2 71.40
water, composed of
{ Oxygen 346 2 3 44.60

{Hydrogen 8 0 0 0
100 libs. sugar, composed of {Oxygen 64 0 0 0
{Charcoal 28 0 0 0

{Hydrogen 0 4 5 9.30
2 libs. 12 oz. 1 gros 28 grs. of dry
{Oxygen 1 10 2 28.76
yeast, composed of
{ Charcoal 0 12 4 59
{ Azote 0 0 5 2.94
———————— ———
Total
510 0 0 0
weight

Table III. Recapitulation of these Elements.

libs. oz. gros grs.
Oxygen:
of the water 340 0 0 0} libs. oz. gros grs.
of the water in the yeast 6 2 3 44.60} 411 12 6 1.36
of the sugar 64 0 0 0}
of the dry yeast 1 10 2 28.76}
Hydrogen:
of the water 60 0 0 0}
of the water in the yeast 1 1 2 71.40} 69 6 0 8.70
of the sugar 8 0 0 0}
of the dry yeast 0 4 5 9.30}
Charcoal:
of the sugar 28 0 0 0}
of the yeast 0 12 4 59.00} 28 12 459.00
Azote of the yeast - - - - } 0 0 5 2.94
———————— ———
In all 510 0 0 0

Having thus accurately determined the nature and quantity of the
constituent elements of the materials submitted to fermentation, we have
next to examine the products resulting from that process. For this purpose, I
placed the above 510 libs. of fermentable liquor in a proper[26] apparatus,
by means of which I could accurately determine the quantity and quality of
gas disengaged during the fermentation, and could even weigh every one of
the products separately, at any period of the process I judged proper. An
hour or two after the substances are mixed together, especially if they are
kept in a temperature of from 15° (65.75°) to 18° (72.5°) of the
thermometer, the first marks of fermentation commence; the liquor turns
thick and frothy, little globules of air are disengaged, which rise and burst at
the surface; the quantity of these globules quickly increases, and there is a
rapid and abundant production of very pure carbonic acid, accompanied
with a scum, which is the yeast separating from the mixture. After some
days, less or more according to the degree of heat, the intestine motion and

disengagement of gas diminish; but these do not cease entirely, nor is the
fermentation completed for a considerable time. During the process, 35 libs.
5 oz. 4 gros 19 grs. of dry carbonic acid are disengaged, which carry
alongst with them 13 libs. 14 oz. 5 gros of water. There remains in the
vessel 460 libs. 11 oz. 6 gros 53 grs. of vinous liquor, slightly acidulous.
This is at first muddy, but clears of itself, and deposits a portion of yeast.
When we separately analise all these substances, which is effected by very
troublesome processes, we have the results as given in the following Tables.
This process, with all the subordinate calculations and analyses, will be
detailed at large in the Memoirs of the Academy.

Table IV. Product of Fermentation.

libs. oz. gros grs.
35 libs. 5 oz. 4 gros 19 grs. of
{Oxygen 25 7 1 34
carbonic acid, composed of
{Charcoal 9 14 2 57

408 libs. 15 oz. 5 gros 14 grs.
{Oxygen 347 10 0 59
of water, composed of
{Hydrogen 61 5 4 27

{Oxygen, combined
31 6 1 64
with hydrogen
57 libs. 11 oz. 1 gros 58 grs. of {Hydrogen, combined
5 8 5 3
dry alkohol, composed of with oxygen
{Hydrogen, combined
4 0 5 0
with charcoal
{Charcoal, combined
16 11 5 63
with hydrogen

2 libs. 8 oz. of dry acetous
{Hydrogen 0 2 4 0
acid, composed of
{Oxygen 1 11 4 0
{Charcoal 0 10 0 0

4 libs. 1 oz. 4 gros 3 grs. of
residuum of sugar, composed {Hydrogen 0 5 1 67
of
{Oxygen 2 9 7 27
{Charcoal 1 2 2 53

{Hydrogen 0 2 2 41
1 lib. 6 oz. 0 gros 5 grs. of dry
{Oxygen 0 13 1 14
yeast, composed of
{ Charcoal 0 62 30
{Azote 0 0 2 37
———— —— ——
510 libs. Total 510 0 0 0

Table V. Recapitulation of the Products.

libs. oz. gros grs.
Water 347 10 0 59
Carbonic acid 25 7 1 34
409 libs. 10 oz. 0 gros Alkohol
31 6 1 64
54 grs. of oxygen
Acetous acid 1 11 4 0
contained in the
Residuum of sugar 2 9 7 27
Yeast 0 13 1 14
Carbonic acid 9 14 2 57
28 libs. 12 oz. 5 gros 59 Alkohol 16 11 5 63
grs. of charcoal Acetous acid 0 10 0 0
contained in the Residuum of sugar 1 2 2 53
Yeast 0 6 2 30
Water 61 5 4 27
Water of the
5 8 5 3
alkohol
71 libs. 8 oz. 6 gros 66 Combined with the
grs. of hydrogen charcoal of the 4 0 5 0
contained in the alko.
Acetous acid 0 2 4 0
Residuum of sugar 0 5 1 67
Yeast 0 2 2 41
2 gros 37 grs. of
0 0 2 37
azote in the yeast
—— ————————— ———
510 libs. Total 510 0 0 0

In these results, I have been exact, even to grains; not that it is possible, in
experiments of this nature, to carry our accuracy so far, but as the
experiments were made only with a few pounds of sugar, and as, for the
sake of comparison, I reduced the results of the actual experiments to the
quintal or imaginary hundred pounds, I thought it necessary to leave the
fractional parts precisely as produced by calculation.
When we consider the results presented by these tables with attention, it is
easy to discover exactly what occurs during fermentation. In the first place,
out of the 100 libs. of sugar employed, 4 libs. 1 oz. 4 gros 3 grs. remain,

without having suffered decomposition; so that, in reality, we have only
operated upon 95 libs. 14 oz. 3 gros 69 grs. of sugar; that is to say, upon 61
libs. 6 oz. 45 grs. of oxygen, 7 libs. 10 oz. 6 gros 6 grs. of hydrogen, and 26
libs. 13 oz. 5 gros 19 grs. of charcoal. By comparing these quantities, we
find that they are fully sufficient for forming the whole of the alkohol,
carbonic acid and acetous acid produced by the fermentation. It is not,
therefore, necessary to suppose that any water has been decomposed during
the experiment, unless it be pretended that the oxygen and hydrogen exist in
the sugar in that state. On the contrary, I have already made it evident that
hydrogen, oxygen and charcoal, the three constituent elements of
vegetables, remain in a state of equilibrium or mutual union with each other
which subsists so long as this union remains undisturbed by increased
temperature, or by some new compound attraction; and that then only these
elements combine, two and two together, to form water and carbonic acid.
The effects of the vinous fermentation upon sugar is thus reduced to the
mere separation of its elements into two portions; one part is oxygenated at
the expence of the other, so as to form carbonic acid, whilst the other part,
being deoxygenated in favour of the former, is converted into the
combustible substance alkohol; therefore, if it were possible to reunite
alkohol and carbonic acid together, we ought to form sugar. It is evident that
the charcoal and hydrogen in the alkohol do not exist in the state of oil, they
are combined with a portion of oxygen, which renders them miscible with
water; wherefore these three substances, oxygen, hydrogen, and charcoal,
exist here likewise in a species of equilibrium or reciprocal combination;
and in fact, when they are made to pass through a red hot tube of glass or
porcelain, this union or equilibrium is destroyed, the elements become
combined, two and two, and water and carbonic acid are formed.
I had formally advanced, in my first Memoirs upon the formation of water,
that it was decomposed in a great number of chemical experiments, and
particularly during the vinous fermentation. I then supposed that water
existed ready formed in sugar, though I am now convinced that sugar only
contains the elements proper for composing it. It may be readily conceived,
that it must have cost me a good deal to abandon my first notions, but by
several years reflection, and after a great number of experiments and
observations upon vegetable substances, I have fixed my ideas as above.

I shall finish what I have to say upon vinous fermentation, by observing,
that it furnishes us with the means of analysing sugar and every vegetable
fermentable matter. We may consider the substances submitted to
fermentation, and the products resulting from that operation, as forming an
algebraic equation; and, by successively supposing each of the elements in
this equation unknown, we can calculate their values in succession, and thus
verify our experiments by calculation, and our calculation by experiment
reciprocally. I have often successfully employed this method for correcting
the first results of my experiments, and to direct me in the proper road for
repeating them to advantage. I have explained myself at large upon this
subject, in a Memoir upon vinous fermentation already presented to the
Academy, and which will speedily be published.

FOOTNOTES:
[26] The above apparatus is described in the Third Part.—A.

CHAP. XIV.
Of the Putrefactive Fermentation.

The phenomena of putrefaction are caused, like those of vinous
fermentation, by the operation of very complicated affinities. The
constituent elements of the bodies submitted to this process cease to
continue in equilibrium in the threefold combination, and form themselves
anew into binary combinations[27], or compounds, consisting of two
elements only; but these are entirely different from the results produced by
the vinous fermentation. Instead of one part of the hydrogen remaining
united with part of the water and charcoal to form alkohol, as in the vinous
fermentation, the whole of the hydrogen is dissipated, during putrefaction,
in the form of hydrogen gas, whilst, at the same time, the oxygen and
charcoal, uniting with caloric, escape in the form of carbonic acid gas; so
that, when the whole process is finished, especially if the materials have
been mixed with a sufficient quantity of water, nothing remains but the
earth of the vegetable mixed with a small portion of charcoal and iron. Thus
putrefaction is nothing more than a complete analysis of vegetable
substance, during which the whole of the constituent elements is disengaged
in form of gas, except the earth, which remains in the state of mould[28].
Such is the result of putrefaction when the substances submitted to it
contain only oxygen, hydrogen, charcoal and a little earth. But this case is
rare, and these substances putrify imperfectly and with difficulty, and
require a considerable time to complete their putrefaction. It is otherwise
with substances containing azote, which indeed exists in all animal matters,
and even in a considerable number of vegetable substances. This additional
element is remarkably favourable to putrefaction; and for this reason animal
matter is mixed with vegetable, when the putrefaction of these is wished to
be hastened. The whole art of forming composts and dunghills, for the
purposes of agriculture, consists in the proper application of this admixture.
The addition of azote to the materials of putrefaction not only accelerates
the process, that element likewise combines with part of the hydrogen, and

forms a new substance called volatile alkali or ammoniac. The results
obtained by analysing animal matters, by different processes, leave no room
for doubt with regard to the constituent elements of ammoniac; whenever
the azote has been previously separated from these substances, no
ammoniac is produced; and in all cases they furnish ammoniac only in
proportion to the azote they contain. This composition of ammoniac is
likewise fully proved by Mr Berthollet, in the Memoirs of the Academy for
1785, p. 316. where he gives a variety of analytical processes by which
ammoniac is decomposed, and its two elements, azote and hydrogen,
procured separately.
I already mentioned in Chap. X. that almost all combustible bodies were
capable of combining with each other; hydrogen gas possesses this quality
in an eminent degree, it dissolves charcoal, sulphur, and phosphorus,
producing the compounds named carbonated hydrogen gas, sulphurated
hydrogen gas, and phosphorated hydrogen gas. The two latter of these
gasses have a peculiarly disagreeable flavour; the sulphurated hydrogen gas
has a strong resemblance to the smell of rotten eggs, and the phosphorated
smells exactly like putrid fish. Ammoniac has likewise a peculiar odour, not
less penetrating, or less disagreeable, than these other gasses. From the
mixture of these different flavours proceeds the fetor which accompanies
the putrefaction of animal substances. Sometimes ammoniac predominates,
which is easily perceived by its sharpness upon the eyes; sometimes, as in
feculent matters, the sulphurated gas is most prevalent; and sometimes, as
in putrid herrings, the phosphorated hydrogen gas is most abundant.
I long supposed that nothing could derange or interrupt the course of
putrefaction; but Mr Fourcroy and Mr Thouret have observed some peculiar
phenomena in dead bodies, buried at a certain depth, and preserved to a
certain degree, from contact with air; having found the muscular flesh
frequently converted into true animal fat. This must have arisen from the
disengagement of the azote, naturally contained in the animal substance, by
some unknown cause, leaving only the hydrogen and charcoal remaining,
which are the elements proper for producing fat or oil. This observation
upon the possibility of converting animal substances into fat may some time
or other lead to discoveries of great importance to society. The faeces of
animals, and other excrementitious matters, are chiefly composed of
charcoal and hydrogen, and approach considerably to the nature of oil, of

which they furnish a considerable quantity by distillation with a naked fire;
but the intolerable foetor which accompanies all the products of these
substances prevents our expecting that, at least for a long time, they can be
rendered useful in any other way than as manures.
I have only given conjectural approximations in this Chapter upon the
composition of animal substances, which is hitherto but imperfectly
understood. We know that they are composed of hydrogen, charcoal, azote,
phosphorus, and sulphur, all of which, in a state of quintuple combination,
are brought to the state of oxyd by a larger or smaller quantity of oxygen.
We are, however, still unacquainted with the proportions in which these
substances are combined, and must leave it to time to complete this part of
chemical analysis, as it has already done with several others.

FOOTNOTES:
[27] Binary combinations are such as consist of two simple elements combined
together. Ternary, and quaternary, consist of three and four elements.—E.
[28] In the Third Part will be given the description of an apparatus proper for
being used in experiments of this kind.—A.

CHAP. XV.
Of the Acetous Fermentation.

The acetous fermentation is nothing more than the acidification or
oxygenation of wine[29], produced in the open air by means of the
absorption of oxygen. The resulting acid is the acetous acid, commonly
called Vinegar, which is composed of hydrogen and charcoal united
together in proportions not yet ascertained, and changed into the acid state
by oxygen. As vinegar is an acid, we might conclude from analogy that it
contains oxygen, but this is put beyond doubt by direct experiments: In the
first place, we cannot change wine into vinegar without the contact of air
containing oxygen; secondly, this process is accompanied by a diminution
of the volume of the air in which it is carried on from the absorption of its
oxygen; and, thirdly, wine may be changed into vinegar by any other means
of oxygenation.
Independent of the proofs which these facts furnish of the acetous acid
being produced by the oxygenation of wine, an experiment made by Mr
Chaptal, Professor of Chemistry at Montpellier, gives us a distinct view of
what takes place in this process. He impregnated water with about its own
bulk of carbonic acid from fermenting beer, and placed this water in a cellar
in vessels communicating with the air, and in a short time the whole was
converted into acetous acid. The carbonic acid gas procured from beer vats
in fermentation is not perfectly pure, but contains a small quantity of
alkohol in solution, wherefore water impregnated with it contains all the
materials necessary for forming the acetous acid. The alkohol furnishes
hydrogen and one portion of charcoal, the carbonic acid furnishes oxygen
and the rest of the charcoal, and the air of the atmosphere furnishes the rest
of the oxygen necessary for changing the mixture into acetous acid. From
this observation it follows, that nothing but hydrogen is wanting to convert
carbonic acid into acetous acid; or more generally, that, by means of
hydrogen, and according to the degree of oxygenation, carbonic acid may
be changed into all the vegetable acids; and, on the contrary, that, by

depriving any of the vegetable acids of their hydrogen, they may be
converted into carbonic acid.
Although the principal facts relating to the acetous acid are well known, yet
numerical exactitude is still wanting, till furnished by more exact
experiments than any hitherto performed; wherefore I shall not enlarge any
farther upon the subject. It is sufficiently shown by what has been said, that
the constitution of all the vegetable acids and oxyds is exactly conformable
to the formation of vinegar; but farther experiments are necessary to teach
us the proportion of the constituent elements in all these acids and oxyds.
We may easily perceive, however, that this part of chemistry, like all the rest
of its divisions, makes rapid progress towards perfection, and that it is
already rendered greatly more simple than was formerly believed.

FOOTNOTES:
[29] The word Wine, in this chapter, is used to signify the liquor produced by the
vinous fermentation, whatever vegetable substance may have been used for
obtaining it.—E.

CHAP. XVI.
Of the Formation of Neutral Salts, and of their different Bases.

We have just seen that all the oxyds and acids from the animal and
vegetable kingdoms are formed by means of a small number of simple
elements, or at least of such as have not hitherto been susceptible of
decomposition, by means of combination with oxygen; these are azote,
sulphur, phosphorus, charcoal, hydrogen, and the muriatic radical[30]. We
may justly admire the simplicity of the means employed by nature to
multiply qualities and forms, whether by combining three or four acidifiable
bases in different proportions, or by altering the dose of oxygen employed
for oxydating or acidifying them. We shall find the means no less simple
and diversified, and as abundantly productive of forms and qualities, in the
order of bodies we are now about to treat of.
Acidifiable substances, by combining with oxygen, and their consequent
conversion into acids, acquire great susceptibility of farther combination;
they become capable of uniting with earthy and metallic bodies, by which
means neutral salts are formed. Acids may therefore be considered as true
salifying principles, and the substances with which they unite to form
neutral salts may be called salifiable bases: The nature of the union which
these two principles form with each other is meant as the subject of the
present chapter.
This view of the acids prevents me from considering them as salts, though
they are possessed of many of the principal properties of saline bodies, as
solubility in water, &c. I have already observed that they are the result of a
first order of combination, being composed of two simple elements, or at
least of elements which act as if they were simple, and we may therefore
rank them, to use the language of Stahl, in the order of mixts. The neutral
salts, on the contrary, are of a secondary order of combination, being
formed by the union of two mixts with each other, and may therefore be
termed compounds. Hence I shall not arrange the alkalies[31] or earths in the

class of salts, to which I allot only such as are composed of an oxygenated
substance united to a base.
I have already enlarged sufficiently upon the formation of acids in the
preceding chapter, and shall not add any thing farther upon that subject; but
having as yet given no account of the salifiable bases which are capable of
uniting with them to form neutral salts, I mean, in this chapter, to give an
account of the nature and origin of each of these bases. These are potash,
soda, ammoniac, lime, magnesia, barytes, argill[32], and all the metallic
bodies.

§ 1. Of Potash.

We have already shown, that, when a vegetable substance is submitted to
the action of fire in distilling vessels, its component elements, oxygen,
hydrogen, and charcoal, which formed a threefold combination in a state of
equilibrium, unite, two and two, in obedience to affinities which act
conformable to the degree of heat employed. Thus, at the first application of
the fire, whenever the heat produced exceeds the temperature of boiling
water, part of the oxygen and hydrogen unite to form water; soon after the
rest of the hydrogen, and part of the charcoal, combine into oil; and, lastly,
when the fire is pushed to the red heat, the oil and water, which had been
formed in the early part of the process, become again decomposed, the
oxygen and charcoal unite to form carbonic acid, a large quantity of
hydrogen gas is set free, and nothing but charcoal remains in the retort.
A great part of these phenomena occur during the combustion of vegetables
in the open air; but, in this case, the presence of the air introduces three new
substances, the oxygen and azote of the air and caloric, of which two at
least produce considerable changes in the results of the operation. In
proportion as the hydrogen of the vegetable, or that which results from the
decomposition of the water, is forced out in the form of hydrogen gas by the
progress of the fire, it is set on fire immediately upon getting in contact with
the air, water is again formed, and the greater part of the caloric of the two
gasses becoming free produces flame. When all the hydrogen gas is driven
out, burnt, and again reduced to water, the remaining charcoal continues to
burn, but without flame; it is formed into carbonic acid, which carries off a

portion of caloric sufficient to give it the gasseous form; the rest of the
caloric, from the oxygen of the air, being set free, produces the heat and
light observed during the combustion of charcoal. The whole vegetable is
thus reduced into water and carbonic acid, and nothing remains but a small
portion of gray earthy matter called ashes, being the only really fixed
principles which enter into the constitution of vegetables.
The earth, or rather ashes, which seldom exceeds a twentieth part of the
weight of the vegetable, contains a substance of a particular nature, known
under the name of fixed vegetable alkali, or potash. To obtain it, water is
poured upon the ashes, which dissolves the potash, and leaves the ashes
which are insoluble; by afterwards evaporating the water, we obtain the
potash in a white concrete form: It is very fixed even in a very high degree
of heat. I do not mean here to describe the art of preparing potash, or the
method of procuring it in a state of purity, but have entered upon the above
detail that I might not use any word not previously explained.
The potash obtained by this process is always less or more saturated with
carbonic acid, which is easily accounted for: As the potash does not form,
or at least is not set free, but in proportion as the charcoal of the vegetable is
converted into carbonic acid by the addition of oxygen, either from the air
or the water, it follows, that each particle of potash, at the instant of its
formation, or at least of its liberation, is in contact with a particle of
carbonic acid, and, as there is a considerable affinity between these two
substances, they naturally combine together. Although the carbonic acid has
less affinity with potash than any other acid, yet it is difficult to separate the
last portions from it. The most usual method of accomplishing this is to
dissolve the potash in water; to this solution add two or three times its
weight of quick-lime, then filtrate the liquor and evaporate it in close
vessels; the saline substance left by the evaporation is potash almost
entirely deprived of carbonic acid. In this state it is soluble in an equal
weight of water, and even attracts the moisture of the air with great avidity;
by this property it furnishes us with an excellent means of rendering air or
gas dry by exposing them to its action. In this state it is soluble in alkohol,
though not when combined with carbonic acid; and Mr Berthollet employs
this property as a method of procuring potash in the state of perfect purity.

All vegetables yield less or more of potash in consequence of combustion,
but it is furnished in various degrees of purity by different vegetables;
usually, indeed, from all of them it is mixed with different salts from which
it is easily separable. We can hardly entertain a doubt that the ashes, or earth
which is left by vegetables in combustion, pre-existed in them before they
were burnt, forming what may be called the skeleton, or osseous part of the
vegetable. But it is quite otherwise with potash; this substance has never yet
been procured from vegetables but by means of processes or intermedia
capable of furnishing oxygen and azote, such as combustion, or by means
of nitric acid; so that it is not yet demonstrated that potash may not be a
produce from these operations. I have begun a series of experiments upon
this object, and hope soon to be able to give an account of their results.

§ 2. Of Soda.

Soda, like potash, is an alkali procured by lixiviation from the ashes of
burnt plants, but only from those which grow upon the sea-side, and
especially from the herb kali, whence is derived the name alkali, given to
this substance by the Arabians. It has some properties in common with
potash, and others which are entirely different: In general, these two
substances have peculiar characters in their saline combinations which are
proper to each, and consequently distinguish them from each other; thus
soda, which, as obtained from marine plants, is usually entirely saturated
with carbonic acid, does not attract the humidity of the atmosphere like
potash, but, on the contrary, desiccates, its cristals effloresce, and are
converted into a white powder having all the properties of soda, which it
really is, having only lost its water of cristallization.
Hitherto we are not better acquainted with the constituent elements of soda
than with those of potash, being equally uncertain whether it previously
existed ready formed in the vegetable or is a combination of elements
effected by combustion. Analogy leads us to suspect that azote is a
constituent element of all the alkalies, as is the case with ammoniac; but we
have only slight presumptions, unconfirmed by any decisive experiments,
respecting the composition of potash and soda.

§ 3. Of Ammoniac.

We have, however, very accurate knowledge of the composition of
ammoniac, or volatile alkali, as it is called by the old chemists. Mr
Berthollet, in the Memoirs of the Academy for 1784, p. 316. has proved by
analysis, that 1000 parts of this substance consist of about 807 parts of
azote combined with 193 parts of hydrogen.
Ammoniac is chiefly procurable from animal substances by distillation,
during which process the azote and hydrogen necessary to its formation
unite in proper proportions; it is not, however, procured pure by this
process, being mixed with oil and water, and mostly saturated with carbonic
acid. To separate these substances it is first combined with an acid, the
muriatic for instance, and then disengaged from that combination by the
addition of lime or potash. When ammoniac is thus produced in its greatest
degree of purity it can only exist under the gasseous form, at least in the
usual temperature of the atmosphere, it has an excessively penetrating
smell, is absorbed in large quantities by water, especially if cold and
assisted by compression. Water thus saturated with ammoniac has usually
been termed volatile alkaline fluor; we shall call it either simply ammoniac,
or liquid ammoniac, and ammoniacal gas when it exists in the aëriform
state.

§ 4. Of Lime, Magnesia, Barytes, and Argill.

The composition of these four earths is totally unknown, and, until by new
discoveries their constituent elements are ascertained, we are certainly
authorised to consider them as simple bodies. Art has no share in the
production of these earths, as they are all procured ready formed from
nature; but, as they have all, especially the three first, great tendency to
combination, they are never found pure. Lime is usually saturated with
carbonic acid in the state of chalk, calcarious spars, most of the marbles,
&c.; sometimes with sulphuric acid, as in gypsum and plaster stones; at
other times with fluoric acid forming vitreous or fluor spars; and, lastly, it is
found in the waters of the sea, and of saline springs, combined with
muriatic acid. Of all the salifiable bases it is the most universally spread
through nature.

Magnesia is found in mineral waters, for the most part combined with
sulphuric acid; it is likewise abundant in sea-water, united with muriatic
acid; and it exists in a great number of stones of different kinds.
Barytes is much less common than the three preceding earths; it is found in
the mineral kingdom, combined with sulphuric acid, forming heavy spars,
and sometimes, though rarely, united to carbonic acid.
Argill, or the base of alum, having less tendency to combination than the
other earths, is often found in the state of argill, uncombined with any acid.
It is chiefly procurable from clays, of which, properly speaking, it is the
base, or chief ingredient.

§ 5. Of Metallic Bodies.

The metals, except gold, and sometimes silver, are rarely found in the
mineral kingdom in their metallic state, being usually less or more saturated
with oxygen, or combined with sulphur, arsenic, sulphuric acid, muriatic
acid, carbonic acid, or phosphoric acid. Metallurgy, or the docimastic art,
teaches the means of separating them from these foreign matters; and for
this purpose we refer to such chemical books as treat upon these operations.
We are probably only acquainted as yet with a part of the metallic
substances existing in nature, as all those which have a stronger affinity to
oxygen, than charcoal possesses, are incapable of being reduced to the
metallic state, and, consequently, being only presented to our observation
under the form of oxyds, are confounded with earths. It is extremely
probable that barytes, which we have just now arranged with earths, is in
this situation; for in many experiments it exhibits properties nearly
approaching to those of metallic bodies. It is even possible that all the
substances we call earths may be only metallic oxyds, irreducible by any
hitherto known process.
Those metallic bodies we are at present acquainted with, and which we can
reduce to the metallic or reguline state, are the following seventeen:

1. Arsenic.
2. Molybdena.

3. Tungstein.
4. Manganese.
5. Nickel.
6. Cobalt.
7. Bismuth.
8. Antimony.
9. Zinc.
10. Iron.
11. Tin.
12. Lead.
13. Copper.
14. Mercury.
15. Silver.
16. Platina.
17. Gold.
I only mean to consider these as salifiable bases, without entering at all
upon the consideration of their properties in the arts, and for the uses of
society. In these points of view each metal would require a complete
treatise, which would lead me far beyond the bounds I have prescribed for
this work.

FOOTNOTES:
[30] I have not ventured to omit this element, as here enumerated with the other
principles of animal and vegetable substances, though it is not at all taken notice
of in the preceding chapters as entering into the composition of these bodies.—
E.
[31] Perhaps my thus rejecting the alkalies from the class of salts may be
considered as a capital defect in the method I have adopted, and I am ready to
admit the charge; but this inconvenience is compensated by so many advantages,
that I could not think it of sufficient consequence to make me alter my plan.—A.
[32] Called Alumine by Mr Lavoisier; but as Argill has been in a manner
naturalized to the language for this substance by Mr Kirwan, I have ventured to
use it in preference.—E.

CHAP. XVII.
Continuation of the Observations upon Salifiable Bases, and the
Formation of Neutral Salts.

It is necessary to remark, that earths and alkalies unite with acids to form
neutral salts without the intervention of any medium, whereas metallic
substances are incapable of forming this combination without being
previously less or more oxygenated; strictly speaking, therefore, metals are
not soluble in acids, but only metallic oxyds. Hence, when we put a metal
into an acid for solution, it is necessary, in the first place, that it become
oxygenated, either by attracting oxygen from the acid or from the water; or,
in other words, that a metal cannot be dissolved in an acid unless the
oxygen, either of the acid, or of the water mixed with it, has a stronger
affinity to the metal than to the hydrogen or the acidifiable base; or, what
amounts to the same thing, that no metallic solution can take place without
a previous decomposition of the water, or the acid in which it is made. The
explanation of the principal phenomena of metallic solution depends
entirely upon this simple observation, which was overlooked even by the
illustrious Bergman.
The first and most striking of these is the effervescence, or, to speak less
equivocally, the disengagement of gas which takes place during the
solution; in the solutions made in nitric acid this effervescence is produced
by the disengagement of nitrous gas; in solutions with sulphuric acid it is
either sulphurous acid gas or hydrogen gas, according as the oxydation of
the metal happens to be made at the expence of the sulphuric acid or of the
water. As both nitric acid and water are composed of elements which, when
separate, can only exist in the gasseous form, at least in the common
temperature of the atmosphere, it is evident that, whenever either of these is
deprived of its oxygen, the remaining element must instantly expand and
assume the state of gas; the effervescence is occasioned by this sudden
conversion from the liquid to the gasseous state. The same decomposition,
and consequent formation of gas, takes place when solutions of metals are

made in sulphuric acid: In general, especially by the humid way, metals do
not attract all the oxygen it contains; they therefore reduce it, not into
sulphur, but into sulphurous acid, and as this acid can only exist as gas in
the usual temperature, it is disengaged, and occasions effervescence.
The second phenomenon is, that, when the metals have been previously
oxydated, they all dissolve in acids without effervescence: This is easily
explained; because, not having now any occasion for combining with
oxygen, they neither decompose the acid nor the water by which, in the
former case, the effervescence is occasioned.
A third phenomenon, which requires particular consideration, is, that none
of the metals produce effervescence by solution in oxygenated muriatic
acid. During this process the metal, in the first place, carries off the excess
of oxygen from the oxygenated muriatic acid, by which it becomes
oxydated, and reduces the acid to the state of ordinary muriatic acid. In this
case there is no production of gas, not that the muriatic acid does not tend to
exist in the gasseous state in the common temperature, which it does
equally with the acids formerly mentioned, but because this acid, which
otherwise would expand into gas, finds more water combined with the
oxygenated muriatic acid than is necessary to retain it in the liquid form;
hence it does not disengage like the sulphurous acid, but remains, and
quietly dissolves and combines with the metallic oxyd previously formed
from its superabundant oxygen.
The fourth phenomenon is, that metals are absolutely insoluble in such
acids as have their bases joined to oxygen by a stronger affinity than these
metals are capable of exerting upon that acidifying principle. Hence silver,
mercury, and lead, in their metallic states, are insoluble in muriatic acid,
but, when previously oxydated, they become readily soluble without
effervescence.
From these phenomena it appears that oxygen is the bond of union between
metals and acids; and from this we are led to suppose that oxygen is
contained in all substances which have a strong affinity with acids: Hence it
is very probable the four eminently salifiable earths contain oxygen, and
their capability of uniting with acids is produced by the intermediation of
that element. What I have formerly noticed relative to these earths is

considerably strengthened by the above considerations, viz. that they may
very possibly be metallic oxyds, with which oxygen has a stronger affinity
than with charcoal, and consequently not reducible by any known means.
All the acids hitherto known are enumerated in the following table, the first
column of which contains the names of the acids according to the new
nomenclature, and in the second column are placed the bases or radicals of
these acids, with observations.

Names of the Acids. Names of the Bases, with Observations.

1. Sulphurous }Sulphur.
2. Sulphuric }

3. Phosphorous }Phosphorus.
4. Phosphoric }

5. Muriatic }Muriatic radical or base, hitherto unknown.
6. Oxygenated muriatic }

7. Nitrous }
8. Nitric }Azote.
9. Oxygenated nitric }

10. Carbonic Charcoal

}The bases or radicals of all these acids
11. Acetous }seem to be formed by a combination
12. Acetic }of charcoal and hydrogen;
13. Oxalic }and the only difference seems to be
14. Tartarous }owing to the different proportions in
15. Pyro-tartarous }which these elements combine to form
16. Citric }their bases, and to the different doses
17. Malic }of oxygen in their acidification. A
18. Pyro-lignous }connected series of accurate experiments

19. Pyro-mucous }is still wanted upon this subject.

20. Gallic }Our knowledge of the bases of
21. Prussic }these acids is hitherto imperfect; we
22. Benzoic }only know that they contain hydrogen
23. Succinic }and charcoal as principal elements,
24. Camphoric }and that the prussic acid contains
25. Lactic }azote.
26. Saccholactic }

27. Bombic }The base of these and all acids
28. Formic }procured from animal substances seems
29. Sebacic }to consist of charcoal, hydrogen,
}phosphorous, and azote.

30. Boracic }The bases of these two are hitherto
31. Fluoric }entirely unknown.

32. Antimonic Antimony.
33. Argentic Silver.
34. Arseniac(A) Arsenic.
35. Bismuthic Bismuth.
36. Cobaltic Cobalt.
37. Cupric Copper.
38. Stannic Tin.
39. Ferric Iron.
40. Manganic Manganese.
41. Mercuric(B) Mercury.
42. Molybdic Molybdena.
43. Nickolic Nickel.
44. Auric Gold.
45. Platinic Platina.
46. Plumbic Lead.
47. Tungstic Tungstein.

48. Zincic Zinc.

[Note A: This term swerves a little from the rule in making the name of this
acid terminate in ac instead of ic. The base and acid are distinguished in
French by arsenic and arsenique; but, having chosen the English
termination ic to translate the French ique, I was obliged to use this small
deviation.—E.]
[Note B: Mr Lavoisier has hydrargirique; but mercurius being used for the
base or metal, the name of the acid, as above, is equally regular, and less
harsh.—E.]
In this list, which contains 48 acids, I have enumerated 17 metallic acids
hitherto very imperfectly known, but upon which Mr Berthollet is about to
publish a very important work. It cannot be pretended that all the acids
which exist in nature, or rather all the acidifiable bases, are yet discovered;
but, on the other hand, there are considerable grounds for supposing that a
more accurate investigation than has hitherto been attempted will diminish
the number of the vegetable acids, by showing that several of these, at
present considered as distinct acids, are only modifications of others. All
that can be done in the present state of our knowledge is, to give a view of
chemistry as it really is, and to establish fundamental principles, by which
such bodies as may be discovered in future may receive names, in
conformity with one uniform system.
The known salifiable bases, or substances capable of being converted into
neutral salts by union with acids, amount to 24; viz. 3 alkalies, 4 earths, and
17 metallic substances; so that, in the present state of chemical knowledge,
the whole possible number of neutral salts amounts to 1152[33]. This
number is upon the supposition that the metallic acids are capable of
dissolving other metals, which is a new branch of chemistry not hitherto
investigated, upon which depends all the metallic combinations named
vitreous. There is reason to believe that many of these supposable saline
combinations are not capable of being formed, which must greatly reduce
the real number of neutral salts producible by nature and art. Even if we
suppose the real number to amount only to five or six hundred species of
possible neutral salts, it is evident that, were we to distinguish them, after
the manner of the ancients, either by the names of their first discoverers, or

by terms derived from the substances from which they are procured, we
should at last have such a confusion of arbitrary designations, as no
memory could possibly retain. This method might be tolerable in the early
ages of chemistry, or even till within these twenty years, when only about
thirty species of salts were known; but, in the present times, when the
number is augmenting daily, when every new acid gives us 24 or 48 new
salts, according as it is capable of one or two degrees of oxygenation, a new
method is certainly necessary. The method we have adopted, drawn from
the nomenclature of the acids, is perfectly analogical, and, following nature
in the simplicity of her operations, gives a natural and easy nomenclature
applicable to every possible neutral salt.
In giving names to the different acids, we express the common property by
the generical term acid, and distinguish each species by the name of its
peculiar acidifiable base. Hence the acids formed by the oxygenation of
sulphur, phosphorus, charcoal, &c. are called sulphuric acid, phosphoric
acid, carbonic acid, &c. We thought it likewise proper to indicate the
different degrees of saturation with oxygen, by different terminations of the
same specific names. Hence we distinguish between sulphurous and
sulphuric, and between phosphorous and phosphoric acids, &c.
By applying these principles to the nomenclature of neutral salts, we give a
common term to all the neutral salts arising from the combination of one
acid, and distinguish the species by adding the name of the salifiable base.
Thus, all the neutral salts having sulphuric acid in their composition are
named sulphats; those formed by the phosphoric acid, phosphats, &c. The
species being distinguished by the names of the salifiable bases gives us
sulphat of potash, sulphat of soda, sulphat of ammoniac, sulphat of lime,
sulphat of iron, &c. As we are acquainted with 24 salifiable bases, alkaline,
earthy, and metallic, we have consequently 24 sulphats, as many phosphats,
and so on through all the acids. Sulphur is, however, susceptible of two
degrees of oxygenation, the first of which produces sulphurous, and the
second, sulphuric acid; and, as the neutral salts produced by these two
acids, have different properties, and are in fact different salts, it becomes
necessary to distinguish these by peculiar terminations; we have therefore
distinguished the neutral salts formed by the acids in the first or lesser
degree of oxygenation, by changing the termination at into ite, as sulphites,
phosphites[34], &c. Thus, oxygenated or acidified sulphur, in its two degrees

of oxygenation is capable of forming 48 neutral salts, 24 of which are
sulphites, and as many sulphats; which is likewise the case with all the
acids capable of two degrees of oxygenation[35].
It were both tiresome and unnecessary to follow these denominations
through all the varieties of their possible application; it is enough to have
given the method of naming the various salts, which, when once well
understood, is easily applied to every possible combination. The name of
the combustible and acidifiable body being once known, the names of the
acid it is capable of forming, and of all the neutral combinations the acid is
susceptible of entering into, are most readily remembered. Such as require a
more complete illustration of the methods in which the new nomenclature is
applied will, in the Second Part of this book, find Tables which contain a
full enumeration of all the neutral salts, and, in general, all the possible
chemical combinations, so far as is consistent with the present state of our
knowledge. To these I shall subjoin short explanations, containing the best
and most simple means of procuring the different species of acids, and
some account of the general properties of the neutral salts they produce.
I shall not deny, that, to render this work more complete, it would have been
necessary to add particular observations upon each species of salt, its
solubility in water and alkohol, the proportions of acid and of salifiable base
in its composition, the quantity of its water of cristallization, the different
degrees of saturation it is susceptible of, and, finally, the degree of force or
affinity with which the acid adheres to the base. This immense work has
been already begun by Messrs Bergman, Morveau, Kirwan, and other
celebrated chemists, but is hitherto only in a moderate state of
advancement, even the principles upon which it is founded are not perhaps
sufficiently accurate.
These numerous details would have swelled this elementary treatise to
much too great a size; besides that, to have gathered the necessary
materials, and to have completed all the series of experiments requisite,
must have retarded the publication of this book for many years. This is a
vast field for employing the zeal and abilities of young chemists, whom I
would advise to endeavour rather to do well than to do much, and to
ascertain, in the first place, the composition of the acids, before entering
upon that of the neutral salts. Every edifice which is intended to resist the

ravages of time should be built upon a sure foundation; and, in the present
state of chemistry, to attempt discoveries by experiments, either not
perfectly exact, or not sufficiently rigorous, will serve only to interrupt its
progress, instead of contributing to its advancement.

FOOTNOTES:
[33] This number excludes all triple salts, or such as contain more than one
salifiable base, all the salts whose bases are over or under saturated with acid,
and those formed by the nitro-muriatic acid.—E.
[34] As all the specific names of the acids in the new nomenclature are
adjectives, they would have applied severally to the various salifiable bases,
without the invention of other terms, with perfect distinctness. Thus, sulphurous
potash, and sulphuric potash, are equally distinct as sulphite of potash, and
sulphat of potash; and have the advantage of being more easily retained in the
memory, because more naturally arising from the acids themselves, than the
arbitrary terminations adopted by Mr Lavoisier.—E.
[35] There is yet a third degree of oxygenation of acids, as the oxygenated
muriatic and oxygenated nitric acids. The terms applicable to the neutral salts
resulting from the union of these acids with salifiable bases is supplied by the
Author in the Second Part of this Work. These are formed by prefixing the word
oxygenated to the name of the salt produced by the second degree of
oxygenation. Thus, oxygenated muriat of potash, oxygenated nitrat of soda, &c.
—E.

PART II.

Of the Combination of Acids with Salifiable Bases,
and of the Formation of Neutral Salts.

INTRODUCTION.
If I had strictly followed the plan I at first laid down for the conduct of this
work, I would have confined myself, in the Tables and accompanying
observations which compose this Second Part, to short definitions of the
several known acids, and abridged accounts of the processes by which they
are obtainable, with a mere nomenclature or enumeration of the neutral salts
which result from the combination of these acids with the various salifiable
bases. But I afterwards found that the addition of similar Tables of all the
simple substances which enter into the composition of the acids and oxyds,
together with the various possible combinations of these elements, would
add greatly to the utility of this work, without being any great increase to its
size. These additions, which are all contained in the twelve first sections of
this Part, and the Tables annexed to these, form a kind of recapitulation of
the first fifteen Chapters of the First Part: The rest of the Tables and
Sections contain all the saline combinations.
It must be very apparent that, in this Part of the Work, I have borrowed
greatly from what has been already published by Mr de Morveau in the
First Volume of the Encyclopedie par ordre des Matières. I could hardly
have discovered a better source of information, especially when the
difficulty of consulting books in foreign languages is considered. I make
this general acknowledgment on purpose to save the trouble of references to
Mr de Morveau's work in the course of the following part of mine.

TABLE OF SIMPLE SUBSTANCES.

Simple substances belonging to all the kingdoms of nature, which may be
considered as the elements of bodies.

New Names. Correspondent old Names.

Light Light.

Caloric {Heat.
{Principle or element of heat.
{Fire. Igneous fluid.
{Matter of fire and of heat.

Oxygen {Dephlogisticated air.
{Empyreal air.
{Vital air, or
{Base of vital air.

Azote {Phlogisticated air or gas.
{Mephitis, or its base.

Hydrogen {Inflammable air or gas,
{or the base of inflammable air.

Oxydable and Acidifiable simple Substance not Metallic.

New Names. Correspondent old names.
Sulphur }
Phosphorous }The same names.
Charcoal }

Muriatic radical }
Fluoric radical }Still unknown.
Boracic radical }

Oxydable and Acidifiable simple Metallic Bodies

New Names. Correspondent Old Names.
Antimony } { Antimony.
Arsenic } { Arsenic.
Bismuth } { Bismuth.
Cobalt } { Cobalt.

Copper } { Copper.
Gold } { Gold.
Iron } { Iron.
Lead } Regulus of { Lead.
Manganese } { Manganese.
Mercury } { Mercury.
Molybdena } { Molybdena.
Nickel } { Nickel.
Platina } { Platina.
Silver } { Silver.
Tin } { Tin.
Tungstein } { Tungstein.
Zinc } { Zinc.

Salifiable simple Earthy Substances.

New Names. Correspondent old Names.

Lime {Chalk, calcareous earth.
{Quicklime.

Magnesia {Magnesia, base of Epsom salt.
{Calcined or caustic magnesia.

Barytes Barytes, or heavy earth.
Argill Clay, earth of alum.
Silex Siliceous or vitrifiable earth.

Sect. I.—Observations upon the Table of Simple Substances.

The principle object of chemical experiments is to decompose natural
bodies, so as separately to examine the different substances which enter into
their composition. By consulting chemical systems, it will be found that this
science of chemical analysis has made rapid progress in our own times.

Formerly oil and salt were considered as elements of bodies, whereas later
observation and experiment have shown that all salts, instead of being
simple, are composed of an acid united to a base. The bounds of analysis
have been greatly enlarged by modern discoveries[36]; the acids are shown
to be composed of oxygen, as an acidifying principle common to all, united
in each to a particular base. I have proved what Mr Haffenfratz had before
advanced, that these radicals of the acids are not all simple elements, many
of them being, like the oily principle, composed of hydrogen and charcoal.
Even the bases of neutral salts have been proved by Mr Berthollet to be
compounds, as he has shown that ammoniac is composed of azote and
hydrogen.
Thus, as chemistry advances towards perfection, by dividing and
subdividing, it is impossible to say where it is to end; and these things we at
present suppose simple may soon be found quite otherwise. All we dare
venture to affirm of any substance is, that it must be considered as simple in
the present state of our knowledge, and so far as chemical analysis has
hitherto been able to show. We may even presume that the earths must soon
cease to be considered as simple bodies; they are the only bodies of the
salifiable class which have no tendency to unite with oxygen; and I am
much inclined to believe that this proceeds from their being already
saturated with that element. If so, they will fall to be considered as
compounds consisting of simple substances, perhaps metallic, oxydated to a
certain degree. This is only hazarded as a conjecture; and I trust the reader
will take care not to confound what I have related as truths, fixed on the
firm basis of observation and experiment, with mere hypothetical
conjectures.
The fixed alkalies, potash, and soda, are omitted in the foregoing Table,
because they are evidently compound substances, though we are ignorant as
yet what are the elements they are composed of.

Table of compound oxydable and acidifiable bases.

Names of the radicals.

Oxydable or acidifiable { Nitro-muriatic radical or

base, from the mineral { base of the acid formerly
kingdom. { called aqua regia.

{ Tartarous radical or base.
{ Malic. }
{ Citric. }
{ Pyro-lignous. }
Oxydable or acidifiable { Pyro-mucous. }
hydro-carbonous or { Pyro-tartarous. }
carbono-hydrous radicals { Oxalic. }
from the vegetable { Acetous. }
kingdom. { Succinic. } Radicals
{ Benzoic. }
{ Camphoric. }
{ Gallic. }
}
Oxydable or acidifiable { Lactic. }
radicals from the animal { Saccholactic. }
kingdom, which { Formic. }
mostly contain azote, { Bombic. }
and frequently phosphorus. { Sebacic. }
{ Lithic. }
{ Prussic. }

Note.—The radicals from the vegetable kingdom are converted by a first
degree of oxygenation into vegetable oxyds, such as sugar, starch, and gum
or mucus: Those of the animal kingdom by the same means form animal
oxyds, as lymph, &c.—A.

Sect. II.—Observations upon the Table of Compound Radicals.

The older chemists being unacquainted with the composition of acids, and
not suspecting them to be formed by a peculiar radical or base for each,
united to an acidifying principle or element common to all, could not
consequently give any name to substances of which they had not the most

distant idea. We had therefore to invent a new nomenclature for this subject,
though we were at the same time sensible that this nomenclature must be
susceptible of great modification when the nature of the compound radicals
shall be better understood[37].
The compound oxydable and acidifiable radicals from the vegetable and
animal kingdoms, enumerated in the foregoing table, are not hitherto
reducible to systematic nomenclature, because their exact analysis is as yet
unknown. We only know in general, by some experiments of my own, and
some made by Mr Hassenfratz, that most of the vegetable acids, such as the
tartarous, oxalic, citric, malic, acetous, pyro-tartarous, and pyromucous,
have radicals composed of hydrogen and charcoal, combined in such a way
as to form single bases, and that these acids only differ from each other by
the proportions in which these two substances enter into the composition of
their bases, and by the degree of oxygenation which these bases have
received. We know farther, chiefly from the experiments of Mr Berthollet,
that the radicals from the animal kingdom, and even some of those from
vegetables, are of a more compound nature, and, besides hydrogen and
charcoal, that they often contain azote, and sometimes phosphorus; but we
are not hitherto possessed of sufficiently accurate experiments for
calculating the proportions of these several substances. We are therefore
forced, in the manner of the older chemists, still to name these acids after
the substances from which they are procured. There can be little doubt that
these names will be laid aside when our knowledge of these substances
becomes more accurate and extensive; the terms hydro-carbonous, hydro-
carbonic, carbono-hydrous, and carbono hydric[38], will then become
substituted for those we now employ, which will then only remain as
testimonies of the imperfect state in which this part of chemistry was
transmitted to us by our predecessors.
It is evident that the oils, being composed of hydrogen and charcoal
combined, are true carbono-hydrous or hydro-carbonous radicals; and,
indeed, by adding oxygen, they are convertible into vegetable oxyds and
acids, according to their degrees of oxygenation. We cannot, however,
affirm that oils enter in their entire state into the composition of vegetable
oxyds and acids; it is possible that they previously lose a part either of their
hydrogen or charcoal, and that the remaining ingredients no longer exist in

the proportions necessary to constitute oils. We still require farther
experiments to elucidate these points.
Properly speaking, we are only acquainted with one compound radical from
the mineral kingdom, the nitro-muriatic, which is formed by the
combination of azote with the muriatic radical. The other compound
mineral acids have been much less attended to, from their producing less
striking phenomena.

Sect. III.—Observations upon the Combinations of Light and
Caloric with different Substances.

I have not constructed any table of the combinations of light and caloric
with the various simple and compound substances, because our conceptions
of the nature of these combinations are not hitherto sufficiently accurate.
We know, in general, that all bodies in nature are imbued, surrounded, and
penetrated in every way with caloric, which fills up every interval left
between their particles; that, in certain cases, caloric becomes fixed in
bodies, so as to constitute a part even of their solid substance, though it
more frequently acts upon them with a repulsive force, from which, or from
its accumulation in bodies to a greater or lesser degree, the transformation
of solids into fluids, and of fluids to aëriform elasticity, is entirely owing.
We have employed the generic name gas to indicate this aëriform state of
bodies produced by a sufficient accumulation of caloric; so that, when we
wish to express the aëriform state of muriatic acid, carbonic acid, hydrogen,
water, alkohol, &c. we do it by adding the word gas to their names; thus
muriatic acid gas, carbonic acid gas, hydrogen gas, aqueous gas, alkoholic
gas, &c.
The combinations of light, and its mode of acting upon different bodies, is
still less known. By the experiments of Mr Berthollet, it appears to have
great affinity with oxygen, is susceptible of combining with it, and
contributes alongst with caloric to change it into the state of gas.
Experiments upon vegetation give reason to believe that light combines
with certain parts of vegetables, and that the green of their leaves, and the
various colours of their flowers, is chiefly owing to this combination. This
much is certain, that plants which grow in darkness are perfectly white,

languid, and unhealthy, and that to make them recover vigour, and to
acquire their natural colours, the direct influence of light is absolutely
necessary. Somewhat similar takes place even upon animals: Mankind
degenerate to a certain degree when employed in sedentary manufactures,
or from living in crowded houses, or in the narrow lanes of large cities;
whereas they improve in their nature and constitution in most of the country
labours which are carried on in the open air. Organization, sensation,
spontaneous motion, and all the operations of life, only exist at the surface
of the earth, and in places exposed to the influence of light. Without it
nature itself would be lifeless and inanimate. By means of light, the
benevolence of the Deity hath filled the surface of the earth with
organization, sensation, and intelligence. The fable of Promotheus might
perhaps be considered as giving a hint of this philosophical truth, which had
even presented itself to the knowledge of the ancients. I have intentionally
avoided any disquisitions relative to organized bodies in this work, for
which reason the phenomena of respiration, sanguification, and animal heat,
are not considered; but I hope, at some future time, to be able to elucidate
these curious subjects.

[Trancriber's note: The following table has been split into four sections
ease reading]

TABLE of the binary Combinations of Oxygen with simple
Substances

Combinations of Names of the
oxygen with simple simple First degree of oxygenation.
non-metallic substances.
substances. New Names. Ancient Names.
Vital or
Caloric Oxygen gas dephlogisticated
air
Hydrogen. Water(A).
Nitrous oxyd, or
Azote Nitrous gas or air
base of nitrous gas

Oxyd of charcoal,
Charcoal Unknown
or carbonic oxyd
Sulphur Oxyd of sulphur Soft sulphur
Oxyd of
phosphorus
Phosphorus {Residuum from
the combustion of
phosphorus
Muriatic
Muriatic oxyd Unknown
radical
Fluoric radical Fluoric oxyd Unknown
Boracic
Boracic oxyd Unknown
radical

Combinations of Grey oxyd of Grey calx of
Antimony
oxygen with the antimony antimony
simple metallic Silver Oxyd of silver Calx of silver
substances. Grey oxyd of Grey calx of
Arsenic
arsenic arsenic
Grey oxyd of Grey calx of
Bismuth
bismuth bismuth
Grey calx of
Cobalt Grey oxyd of cobalt
cobalt
Brown oxyd of Brown calx of
Copper
copper copper
Tin Grey oxyd of tin Grey calx of tin
Iron Black oxyd of iron Martial ethiops
Black oxyd of Black calx of
Manganese
manganese manganese
Black oxyd of Ethiops
Mercury
mercury mineral(B)
Calx of
Molybdena Oxyd of molybdena
molybdena
Nickel Oxyd of nickel Calx of nickel

Yellow oxyd of Yellow calx of
Gold
gold gold
Yellow oxyd of Yellow calx of
Platina
platina platina
Lead Grey oxyd of lead Grey calx of lead
Tungstein Oxyd of Tungstein Calx of Tungstein
Zinc Grey oxyd of zinc Grey calx of zinc

Names of the
simple Second degree of oxygenation.
substances.
New Names. Ancient Names.
Caloric
Hydrogen.
Smoaking nitrous
Azote Nitrous acid
Combinations of acid
oxygen with simple Charcoal Carbonous acid Unknown
non-metallic Sulphurous
substances. Sulphur Sulphureous acid
acid
Phosphorous Volatile acid of
Phosphorus
acid phosphorus
Muriatic
Muriatous acid Unknown
radical
Fluoric radical Fluorous acid Unknown
Boracic
Boracous acid Unknown
radical

Combinations of White calx of
White oxyd of
oxygen with the Antimony antimony,
antimony
simple metallic diaphoretic antimony
substances. Silver

White oxyd of
Arsenic White calx of arsenic
arsenic
White oxyd of White calx of
Bismuth
bismuth bismuth
Cobalt
Blue and green Blue and green
Copper
oxyds of copper calces of copper
White oxyd of White calx of tin, or
Tin
tin putty of tin
Yellow and red Ochre and rust of
Iron
oxyds of iron iron
White oxyd of White calx of
Manganese
manganese manganese
Turbith mineral, red
Yellow and red
precipitate,
Mercury oxyds of
calcinated mercury,
mercury
precipitate per se
Molybdena
Nickel
Red calx of gold,
Red oxyd of
Gold purple precipitate of
gold
cassius
Platina
Yellow and red Massicot and
Lead
oxyds of lead minium
Tungstein
White oxyd of White calx of zinc,
Zinc
zinc pompholix

Combinations of oxygen Names of the
with simple non-metallic simple Third degree of oxygenation.
substances. substances.

New Names. Ancient Names.
Caloric
Hydrogen.
Pale, or not
Azote Nitric acid smoaking
nitrous acid
Carbonic
Charcoal Fixed air
acid
Sulphuric
Sulphur Vitriolic acid
acid
Phosphoric
Phosphorus Phosphoric acid
acid
Muriatic
Muriatic radical Marine acid
acid
Unknown till
Fluoric radical Fluoric acid
lately
Homberg's
Boracic radical Boracic acid
sedative salt

Combinations of oxygen Antimonic
Antimony
with the simple metallic acid
substances. Argentic
Silver
acid
Arseniac
Arsenic Acid of arsenic
acid
Bismuthic
Bismuth
acid
Cobalt Cobaltic acid
Copper Cupric acid
Tin Stannic acid
Iron Ferric acid
Manganesic
Manganese
acid
Mercuric
Mercury
acid

Molybdic Acid of
Molybdena
acid molybdena
Nickel Nickelic acid
Gold Auric acid
Platina Platinic acid
Lead Plumbic acid
Tungstic Acid of
Tungstein
acid Tungstein
Zinc Zincic acid

Names of the simple Fourth degree of
substances. oxygenation.
New Names. Ancient Names.
Caloric
Hydrogen.
Oxygenated
Azote Unknown acid
nitric
Oxygenated
Charcoal Unknown
Combinations of oxygen carbonic acid
with simple non-metallic Oxygenated
substances. Sulphur Unknown
sulphuric acid
Oxygenated
Phosphorus Unknown
phosphoric acid
Muriatic Oxygenated Dephlogisticated
radical muriatic acid marine acid
Fluoric
radical
Boracic
radical

Combinations of oxygen Antimony
with the simple metallic Silver

substances. Oxygenated
Arsenic Unknown
arseniac acid
Bismuth
Cobalt
Copper
Tin
Iron
Manganese
Mercury
Oxygenated
Molybdena Unknown
molybdic acid
Nickel
Gold
Platina
Lead
Oxygenated
Tungstein Unknown
Tungstic acid
Zinc

[Note A: Only one degree of oxygenation of hydrogen is hitherto known.—
A.]
[Note B: Ethiops mineral is the sulphuret of mercury; this should have been
called black precipitate of mercury.—E.]

Sect. IV.—Observations upon the Combinations of Oxygen with
the simple Substances.

Oxygen forms almost a third of the mass of our atmosphere, and is
consequently one of the most plentiful substances in nature. All the animals
and vegetables live and grow in this immense magazine of oxygen gas, and
from it we procure the greatest part of what we employ in experiments. So

great is the reciprocal affinity between this element and other substances,
that we cannot procure it disengaged from all combination. In the
atmosphere it is united with caloric, in the state of oxygen gas, and this
again is mixed with about two thirds of its weight of azotic gas.
Several conditions are requisite to enable a body to become oxygenated, or
to permit oxygen to enter into combination with it. In the first place, it is
necessary that the particles of the body to be oxygenated shall have less
reciprocal attraction with each other than they have for the oxygen, which
otherwise cannot possibly combine with them. Nature, in this case, may be
assisted by art, as we have it in our power to diminish the attraction of the
particles of bodies almost at will by heating them, or, in other words, by
introducing caloric into the interstices between their particles; and, as the
attraction of these particles for each other is diminished in the inverse ratio
of their distance, it is evident that there must be a certain point of distance
of particles when the affinity they possess with each other becomes less
than that they have for oxygen, and at which oxygenation must necessarily
take place if oxygen be present.
We can readily conceive that the degree of heat at which this phenomenon
begins must be different in different bodies. Hence, on purpose to
oxygenate most bodies, especially the greater part of the simple substances,
it is only necessary to expose them to the influence of the air of the
atmosphere in a convenient degree of temperature. With respect to lead,
mercury, and tin, this needs be but little higher than the medium
temperature of the earth; but it requires a more considerable degree of heat
to oxygenate iron, copper, &c. by the dry way, or when this operation is not
assisted by moisture. Sometimes oxygenation takes place with great
rapidity, and is accompanied by great sensible heat, light, and flame; such is
the combustion of phosphorus in atmospheric air, and of iron in oxygen gas.
That of sulphur is less rapid; and the oxygenation of lead, tin, and most of
the metals, takes place vastly slower, and consequently the disengagement
of caloric, and more especially of light, is hardly sensible.
Some substances have so strong an affinity with oxygen, and combine with
it in such low degrees of temperature, that we cannot procure them in their
unoxygenated state; such is the muriatic acid, which has not hitherto been
decomposed by art, perhaps even not by nature, and which consequently

has only been found in the state of acid. It is probable that many other
substances of the mineral kingdom are necessarily oxygenated in the
common temperature of the atmosphere, and that being already saturated
with oxygen, prevents their farther action upon that element.
There are other means of oxygenating simple substances besides exposure
to air in a certain degree of temperature, such as by placing them in contact
with metals combined with oxygen, and which have little affinity with that
element. The red oxyd of mercury is one of the best substances for this
purpose, especially with bodies which do not combine with that metal. In
this oxyd the oxygen is united with very little force to the metal, and can be
driven out by a degree of heat only sufficient to make glass red hot;
wherefore such bodies as are capable of uniting with oxygen are readily
oxygenated, by means of being mixed with red oxyd of mercury, and
moderately heated. The same effect may be, to a certain degree, produced
by means of the black oxyd of manganese, the red oxyd of lead, the oxyds
of silver, and by most of the metallic oxyds, if we only take care to choose
such as have less affinity with oxygen than the bodies they are meant to
oxygenate. All the metallic reductions and revivifications belong to this
class of operations, being nothing more than oxygenations of charcoal, by
means of the several metallic oxyds. The charcoal combines with the
oxygen and with caloric, and escapes in form of carbonic acid gas, while
the metal remains pure and revivified, or deprived of the oxygen which
before combined with it in the form of oxyd.
All combustible substances may likewise be oxygenated by means of
mixing them with nitrat of potash or of soda, or with oxygenated muriat of
potash, and subjecting the mixture to a certain degree of heat; the oxygen,
in this case, quits the nitrat or the muriat, and combines with the
combustible body. This species of oxygenation requires to be performed
with extreme caution, and only with very small quantities; because, as the
oxygen enters into the composition of nitrats, and more especially of
oxygenated muriats, combined with almost as much caloric as is necessary
for converting it into oxygen gas, this immense quantity of caloric becomes
suddenly free the instant of the combination of the oxygen with the
combustible body, and produces such violent explosions as are perfectly
irresistible.

By the humid way we can oxygenate most combustible bodies, and convert
most of the oxyds of the three kingdoms of nature into acids. For this
purpose we chiefly employ the nitric acid, which has a very slight hold of
oxygen, and quits it readily to a great number of bodies by the assistance of
a gentle heat. The oxygenated muriatic acid may be used for several
operations of this kind, but not in them all.
I give the name of binary to the combinations of oxygen with the simple
substances, because in these only two elements are combined. When three
substances are united in one combination I call it ternary, and quaternary
when the combination consists of four substances united.

Table of the combinations of Oxygen with the compound
radicals.

Names of the
Names of the resulting acids.
radicals.
New
Old nomenclature.
nomenclature.
Nitro muriatic Nitro muriatic
Aqua regia.
radical acid
(A)
Tartaric Tartarous acid Unknown till lately.
Malic Malic acid Ditto.
Citric Citric acid Acid of lemons.
Pyro-lignous Pyro-lignous acid Empyreumatic acid of wood.
Pyro-mucous Pyro-mucous acid Empyr. acid of sugar.
Pyro-tartarous
Pyro-tartarous Empyr. acid of tartar.
acid
Oxalic Oxalic acid Acid of sorel.
Acetic {Acetous acid Vinegar, or acid of vinegar.
{Acetic acid Radical vinegar.
Succinic Succinic acid Volatile salt of amber.
Benzoic Benzotic acid Flowers of benzoin.
Camphoric Camphoric acid Unknown till lately.

The astringent principle of
Gallic Gallic acid
vegetables.

(B)
Lactic Lactic acid Acid of sour whey.
Saccholactic Saccholactic acid Unknown till lately.
Formic Formic acid Acid of ants.
Bombic Bombic acid Unknown till lately.
Sebacic Sebacic acid Ditto.
Lithic Lithic acid Urinary calculus.
Prussic Prussic acid Colouring matter of Prussian blue.

[Note A: These radicals by a first degree of oxygenation form vegetable
oxyds, as sugar, starch, mucus, &c.—A.]
[Note B: These radicals by a first degree of oxygenation form the animal
oxyds, as lymph, red part of the blood, animal secretions, &c.—A.]

Sect. V.—Observations upon the Combinations of Oxygen with
the Compound Radicals.

I published a new theory of the nature and formation of acids in the
Memoirs of the Academy for 1776, p. 671. and 1778, p. 535. in which I
concluded, that the number of acids must be greatly larger than was till then
supposed. Since that time, a new field of inquiry has been opened to
chemists; and, instead of five or six acids which were then known, near
thirty new acids have been discovered, by which means the number of
known neutral salts have been increased in the same proportion. The nature
of the acidifiable bases, or radicals of the acids, and the degrees of
oxygenation they are susceptible of, still remain to be inquired into. I have
already shown, that almost all the oxydable and acidifiable radicals from
the mineral kingdom are simple, and that, on the contrary, there hardly
exists any radical in the vegetable, and more especially in the animal
kingdom, but is composed of at least two substances, hydrogen and
charcoal, and that azote and phosphorus are frequently united to these, by

which we have compound radicals of two, three, and four bases or simple
elements united.
From these observations, it appears that the vegetable and animal oxyds and
acids may differ from each other in three several ways: 1st, According to
the number of simple acidifiable elements of which their radicals are
composed: 2dly, According to the proportions in which these are combined
together: And, 3dly, According to their different degrees of oxygenation:
Which circumstances are more than sufficient to explain the great variety
which nature produces in these substances. It is not at all surprising, after
this, that most of the vegetable acids are convertible into each other, nothing
more being requisite than to change the proportions of the hydrogen and
charcoal in their composition, and to oxygenate them in a greater or lesser
degree. This has been done by Mr Crell in some very ingenious
experiments, which have been verified and extended by Mr Hassenfratz.
From these it appears, that charcoal and hydrogen, by a first oxygenation,
produce tartarous acid, oxalic acid by a second degree, and acetous or acetic
acid by a third, or higher oxygenation; only, that charcoal seems to exist in
a rather smaller proportion in the acetous and acetic acids. The citric and
malic acids differ little from the preceding acids.
Ought we then to conclude that the oils are the radicals of the vegetable and
animal acids? I have already expressed my doubts upon this subject: 1st,
Although the oils appear to be formed of nothing but hydrogen and
charcoal, we do not know if these are in the precise proportion necessary
for constituting the radicals of the acids: 2dly, Since oxygen enters into the
composition of these acids equally with hydrogen and charcoal, there is no
more reason for supposing them to be composed of oil rather than of water
or of carbonic acid. It is true that they contain the materials necessary for all
these combinations, but then these do not take place in the common
temperature of the atmosphere; all the three elements remain combined in a
state of equilibrium, which is readily destroyed by a temperature only a
little above that of boiling water[39].

Table of the Binary Combinations of Azote with the Simple
Substances.

Simple
Results of the Combinations.
Substances.
New Nomenclature. Old Nomenclature.
Phlogisticated air, or
Caloric Azotic gas
Mephitis.
Hydrogen Ammoniac Volatile alkali.

{Nitrous oxyd Base of Nitrous gas.
{Nitrous acid Smoaking nitrous acid.
Oxygen {Nitric acid Pale nitrous acid.
{Oxygenated nitric acid Unknown.

{This combination is hitherto
unknown; should it
{ever be discovered, it will be
called, according to
{the principles of our
Charcoal
nomenclature, Azuret of
{Charcoal. Charcoal dissolves in
azotic gas, and
{forms carbonated azotic gas.

Phosphorus. Azuret of phosphorus. Still unknown.

Still unknown. We
{Azuret of sulphur.
know
{that sulphur dissolves in azotic
Sulphur
gas, forming
{sulphurated azotic gas.

{Azote combines with charcoal
and hydrogen, and
{sometimes with phosphorus, in
Compound
the compound

{oxydable and acidifiable bases,
radicals
and is generally
{contained in the radicals of the
animal acids.

{Such combinations are hitherto
unknown; if ever
{discovered, they will form
Metallic
metallic azurets, as
substances {azuret of gold, of silver, &c.

Lime {
Magnesia {
{Entirely unknown. If ever
Barytes
discovered, they will
{form azuret of lime, azuret of
Argill
magnesia, &c.
Potash {
Soda {

Sect. VI.—Observations upon the Combinations of Azote with
the Simple Substances.

Azote is one of the most abundant elements; combined with caloric it forms
azotic gas, or mephitis, which composes nearly two thirds of the
atmosphere. This element is always in the state of gas in the ordinary
pressure and temperature, and no degree of compression or of cold has been
hitherto capable of reducing it either to a solid or liquid form. This is
likewise one of the essential constituent elements of animal bodies, in
which it is combined with charcoal and hydrogen, and sometimes with
phosphorus; these are united together by a certain portion of oxygen, by
which they are formed into oxyds or acids according to the degree of
oxygenation. Hence the animal substances may be varied, in the same way
with vegetables, in three different manners: 1st, According to the number of
elements which enter into the composition of the base or radical: 2dly,

According to the proportions of these elements: 3dly, According to the
degree of oxygenation.
When combined with oxygen, azote forms the nitrous and nitric oxyds and
acids; when with hydrogen, ammoniac is produced. Its combinations with
the other simple elements are very little known; to these we give the name
of Azurets, preserving the termination in uret for all nonoxygenated
compounds. It is extremely probable that all the alkaline substances may
hereafter be found to belong to this genus of azurets.
The azotic gas may be procured from atmospheric air, by absorbing the
oxygen gas which is mixed with it by means of a solution of sulphuret of
potash, or sulphuret of lime. It requires twelve or fifteen days to complete
this process, during which time the surface in contact must be frequently
renewed by agitation, and by breaking the pellicle which forms on the top
of the solution. It may likewise be procured by dissolving animal
substances in dilute nitric acid very little heated. In this operation, the azote
is disengaged in form of gas, which we receive under bell glasses filled
with water in the pneumato-chemical apparatus. We may procure this gas
by deflagrating nitre with charcoal, or any other combustible substance;
when with charcoal, the azotic gas is mixed with carbonic acid gas, which
may be absorbed by a solution of caustic alkali, or by lime water, after
which the azotic gas remains pure. We can procure it in a fourth manner
from combinations of ammoniac with metallic oxyds, as pointed out by Mr
de Fourcroy: The hydrogen of the ammoniac combines with the oxygen of
the oxyd, and forms water, whilst the azote being left free escapes in form
of gas.
The combinations of azote were but lately discovered: Mr Cavendish first
observed it in nitrous gas and acid, and Mr Berthollet in ammoniac and the
prussic acid. As no evidence of its decomposition has hitherto appeared, we
are fully entitled to consider azote as a simple elementary substance.

Table of the Binary Combinations of Hydrogen with Simple
Substances.

Simple Substances. Resulting Compounds.

New Nomenclature. Old Names.
Caloric Hydrogen gas Inflammable air.
Azote Ammoniac Volatile Alkali.
Oxygen Water Water.
Sulphur {Hydruret of sulphur, or }
{sulphuret of hydrogen } Hitherto unknown (A).
Phosphorus {Hydruret of phosphorus, or }
{phosphuret of hydrogen }
Charcoal {Hydro-carbonous, or } Not known till lately.
{carbono-hydrous radicals(B)}
Metallic {Metallic hydrurets(C), as} Hitherto unknown.
substances, as {hydruret of iron, &c.}
iron, &c. { }

[Note A: These combinations take place in the state of gas, and form,
respectively, sulphurated and phosphorated oxygen gas—A.]
[Note B: This combination of hydrogen with charcoal includes the fixed
and volatile oils, and forms the radicals of a considerable part of the
vegetable and animal oxyds and acids. When it takes place in the state of
gas it forms carbonated hydrogen gas.—A.]
[Note C: None of these combinations are known, and it is probable that they
cannot exist, at least in the usual temperature of the atmosphere, owing to
the great affinity of hydrogen for caloric.—A.]

Sect. VII.—Observations upon Hydrogen, and its Combinations
with Simple Substances.

Hydrogen, as its name expresses, is one of the constituent elements of
water, of which it forms fifteen hundredth parts by weight, combined with
eighty-five hundredth parts of oxygen. This substance, the properties and
even existence of which was unknown till lately, is very plentifully
distributed in nature, and acts a very considerable part in the processes of
the animal and vegetable kingdoms. As it possesses so great affinity with
caloric as only to exist in the state of gas, it is consequently impossible to
procure it in the concrete or liquid state, independent of combination.

To procure hydrogen, or rather hydrogen gas, we have only to subject water
to the action of a substance with which oxygen has greater affinity than it
has to hydrogen; by this means the hydrogen is set free, and, by uniting
with caloric, assumes the form of hydrogen gas. Red hot iron is usually
employed for this purpose: The iron, during the process, becomes oxydated,
and is changed into a substance resembling the iron ore from the island of
Elba. In this state of oxyd it is much less attractible by the magnet, and
dissolves in acids without effervescence.
Charcoal, in a red heat, has the same power of decomposing water, by
attracting the oxygen from its combination with hydrogen. In this process
carbonic acid gas is formed, and mixes with the hydrogen gas, but is easily
separated by means of water or alkalies, which absorb the carbonic acid,
and leave the hydrogen gas pure. We may likewise obtain hydrogen gas by
dissolving iron or zinc in dilute sulphuric acid. These two metals
decompose water very slowly, and with great difficulty, when alone, but do
it with great ease and rapidity when assisted by sulphuric acid; the
hydrogen unites with caloric during the process, and is disengaged in form
of hydrogen gas, while the oxygen of the water unites with the metal in the
form of oxyd, which is immediately dissolved in the acid, forming a sulphat
of iron or of zinc.
Some very distinguished chemists consider hydrogen as the phlogiston of
Stahl; and as that celebrated chemist admitted the existence of phlogiston in
sulphur, charcoal, metals, &c. they are of course obliged to suppose that
hydrogen exists in all these substances, though they cannot prove their
supposition; even if they could, it would not avail much, since this
disengagement of hydrogen is quite insufficient to explain the phenomena
of calcination and combustion. We must always recur to the examination of
this question, "Are the heat and light, which are disengaged during the
different species of combustion, furnished by the burning body, or by the
oxygen which combines in all these operations?" And certainly the
supposition of hydrogen being disengaged throws no light whatever upon
this question. Besides, it belongs to those who make suppositions to prove
them; and, doubtless, a doctrine which without any supposition explains the
phenomena as well, and as naturally, as theirs does by supposition, has at
least the advantage of greater simplicity[40].

Table of the Binary Combinations of Sulphur with Simple
Substances.

Simple
Resulting Compounds.
Substances.
New Nomenclature. Old Nomenclature.
Caloric Sulphuric gas

{Oxyd of sulphur Soft sulphur.
Oxygen {Sulphurous acid Sulphureous acid.
{Sulphuric acid Vitriolic acid.

Sulphuret of
Hydrogen
hydrogen}
Azote azote} Unknown Combinations.
Phosphorus phosphorus}
Charcoal charcoal}

Antimony antimony Crude antimony.
Silver silver
Arsenic arsenic Orpiment, realgar.
Bismuth bismuth
Cobalt cobalt
Copper copper Copper pyrites.
Tin tin
Iron iron Iron pyrites.
Manganese manganese
Mercury mercury Ethiops mineral, cinnabar.
Molybdena molybdena
Nickel nickel
Gold gold
Platina platina
Lead lead Galena.
Tungstein tungstein

Zinc zinc Blende.
Alkaline liver of sulphur with fixed
Potash potash
vegetable alkali.
Alkaline liver of sulphur with fixed
Soda soda
mineral alkali.
Volatile liver of sulphur, smoaking
Ammoniac ammoniac
liquor of Boyle.
Lime lime Calcareous liver of sulphur.
Magnesia magnesia Magnesian liver of sulphur.
Barytes barytes Barytic liver of sulphur.
Argill argill Yet unknown.

Sect. VIII.—Observations on Sulphur, and its Combinations.

Sulphur is a combustible substance, having a very great tendency to
combination; it is naturally in a solid state in the ordinary temperature, and
requires a heat somewhat higher than boiling water to make it liquify.
Sulphur is formed by nature in a considerable degree of purity in the
neighbourhood of volcanos; we find it likewise, chiefly in the state of
sulphuric acid, combined with argill in aluminous schistus, with lime in
gypsum, &c. From these combinations it may be procured in the state of
sulphur, by carrying off its oxygen by means of charcoal in a red heat;
carbonic acid is formed, and escapes in the state of gas; the sulphur remains
combined with the clay, lime, &c. in the state of sulphuret, which is
decomposed by acids; the acid unites with the earth into a neutral salt, and
the sulphur is precipitated.

Table of the Binary Combinations of Phosphorus with the
Simple Substances.

Simple Substances. Resulting Compounds.
Caloric Phosphoric gas.

{ Oxyd of phosphorus.
Oxygen { Phosphorous acid.

{ Phosphoric acid.

Hydrogen Phosphuret of hydrogen.
Azote Phosphuret of azote.
Sulphur Phosphuret of Sulphur.
Charcoal Phosphuret of charcoal.
Metallic substances Phosphuret of metals(A).

Potash}
Soda}
Ammoniac} Phosphuret of Potash, Soda, &c.(B)
Lime}
Barytes}
Magnesia}
Argill}

[Note A: Of all these combinations of phosphorus with metals, that with
iron only is hitherto known, forming the substance formerly called Siderite;
neither is it yet ascertained whether, in this combination, the phosphorus be
oxygenated or not.—A.]
[Note B: These combinations of phosphorus with the alkalies and earths are
not yet known; and, from the experiments of Mr Gengembre, they appear to
be impossible—A.]

Sect. IX.—Observations upon Phosphorus, and its
Combinations.

Phosphorus is a simple combustible substance, which was unknown to
chemists till 1667, when it was discovered by Brandt, who kept the process
secret; soon after Kunkel found out Brandt's method of preparation, and
made it public. It has been ever since known by the name of Kunkel's
phosphorus. It was for a long time procured only from urine; and, though
Homberg gave an account of the process in the Memoirs of the Academy
for 1692, all the philosophers of Europe were supplied with it from
England. It was first made in France in 1737, before a committee of the

Academy at the Royal Garden. At present it is procured in a more
commodious and more oeconomical manner from animal bones, which are
real calcareous phosphats, according to the process of Messrs Gahn,
Scheele, Rouelle, &c. The bones of adult animals being calcined to
whiteness, are pounded, and passed through a fine silk sieve; pour upon the
fine powder a quantity of dilute sulphuric acid, less than is sufficient for
dissolving the whole. This acid unites with the calcareous earth of the bones
into a sulphat of lime, and the phosphoric acid remains free in the liquor.
The liquid is decanted off, and the residuum washed with boiling water; this
water which has been used to wash out the adhering acid is joined with
what was before decanted off, and the whole is gradually evaporated; the
dissolved sulphat of lime cristallizes in form of silky threads, which are
removed, and by continuing the evaporation we procure the phosphoric acid
under the appearance of a white pellucid glass. When this is powdered, and
mixed with one third its weight of charcoal, we procure very pure
phosphorus by sublimation. The phosphoric acid, as procured by the above
process, is never so pure as that obtained by oxygenating pure phosphorus
either by combustion or by means of nitric acid; wherefore this latter should
always be employed in experiments of research.
Phosphorus is found in almost all animal substances, and in some plants
which give a kind of animal analysis. In all these it is usually combined
with charcoal, hydrogen, and azote, forming very compound radicals, which
are, for the most part, in the state of oxyds by a first degree of union with
oxygen. The discovery of Mr Hassenfratz, of phosphorus being contained in
charcoal, gives reason to suspect that it is more common in the vegetable
kingdom than has generally been supposed: It is certain, that, by proper
processes, it may be procured from every individual of some of the families
of plants.
As no experiment has hitherto given reason to suspect that phosphorus is a
compound body, I have arranged it with the simple or elementary
substances. It takes fire at the temperature of 32° (104°) of the thermometer.

Table of the Binary Combinations of Charcoal.

Simple
Resulting Compounds.
Substances.
{Oxyd of charcoal Unknown.
Oxygen {Carbonic acid Fixed air, chalky acid.

Sulphur Carburet of sulphur}
Carburet of
Phosphorus Unknown.
phosphorus}
Azote Carburet of azote}

{Carbono-hydrous
radical
Hydrogen {Fixed and volatile oils

{Of these only the carburets of
Metallic
Carburets of metals {iron and zinc are known, and
substances
{were formerly called
Plumbago.

Alkalies and
Carburet of potash, &c. Unknown.
earths

Sect. X.—Observations upon Charcoal, and its Combinations
with Simple Substances.

As charcoal has not been hitherto decomposed, it must, in the present state
of our knowledge, be considered as a simple substance. By modern
experiments it appears to exist ready formed in vegetables; and I have
already remarked, that, in these, it is combined with hydrogen, sometimes
with azote and phosphorus, forming compound radicals, which may be
changed into oxyds or acids according to their degree of oxygenation.
To obtain the charcoal contained in vegetable or animal substances, we
subject them to the action of fire, at first moderate, and afterwards very

strong, on purpose to drive off the last portions of water, which adhere very
obstinately to the charcoal. For chemical purposes, this is usually done in
retorts of stone-ware or porcellain, into which the wood, or other matter, is
introduced, and then placed in a reverberatory furnace, raised gradually to
its greatest heat: The heat volatilizes, or changes into gas, all the parts of the
body susceptible of combining with caloric into that form, and the charcoal,
being more fixed in its nature, remains in the retort combined with a little
earth and some fixed salts.
In the business of charring wood, this is done by a less expensive process.
The wood is disposed in heaps, and covered with earth, so as to prevent the
access of any more air than is absolutely necessary for supporting the fire,
which is kept up till all the water and oil is driven off, after which the fire is
extinguished by shutting up all the air-holes.
We may analyse charcoal either by combustion in air, or rather in oxygen
gas, or by means of nitric acid. In either case we convert it into carbonic
acid, and sometimes a little potash and some neutral salts remain. This
analysis has hitherto been but little attended to by chemists; and we are not
even certain if potash exists in charcoal before combustion, or whether it be
formed by means of some unknown combination during that process.

Sect. XI.—Observations upon the Muriatic, Fluoric, and
Boracic Radicals, and their Combinations.

As the combinations of these substances, either with each other, or with the
other combustible bodies, are hitherto entirely unknown, we have not
attempted to form any table for their nomenclature. We only know that
these radicals are susceptible of oxygenation, and of forming the muriatic,
fluoric, and boracic acids, and that in the acid state they enter into a number
of combinations, to be afterwards detailed. Chemistry has hitherto been
unable to disoxygenate any of them, so as to produce them in a simple state.
For this purpose, some substance must be employed to which oxygen has a
stronger affinity than to their radicals, either by means of single affinity, or
by double elective attraction. All that is known relative to the origin of the
radicals of these acids will be mentioned in the sections set apart for
considering their combinations with the salifiable bases.

Sect. XII.—Observations upon the Combinations of Metals with
each other.

Before closing our account of the simple or elementary substances, it might
be supposed necessary to give a table of alloys or combinations of metals
with each other; but, as such a table would be both exceedingly voluminous
and very unsatisfactory, without going into a series of experiments not yet
attempted, I have thought it adviseable to omit it altogether. All that is
necessary to be mentioned is, that these alloys should be named according
to the metal in largest proportion in the mixture or combination; thus the
term alloy of gold and silver, or gold alloyed with silver, indicates that gold
is the predominating metal.
Metallic alloys, like all other combinations, have a point of saturation. It
would even appear, from the experiments of Mr de la Briche, that they have
two perfectly distinct degrees of saturation.

Table of the Combinations of Azote in the state of Nitrous Acid
with the Salifiable Bases, arranged according to the affinities of
these Bases with the Acid.

Names of the
Names of the neutral salts.
bases.
New nomenclature. Notes.
Barytes Nitrite of barytes. {
Potash potash. {These salts are only
Soda soda. {known of late, and
{have received no
Lime lime.
particular
Magnesia magnesia. {name in the old
Ammoniac ammoniac. {nomenclature.
Argill argill. {

{As metals dissolve both
in nitrous and
{nitric acids, metallic salts
Oxyd of zinc zinc.
must of
{consequence be formed
iron iron.
having
{different degrees of
manganese manganese.
oxygenation.
{Those wherein the metal
cobalt cobalt.
is
nickel nickel. {least oxygenated must be
{called Nitrites, when
lead lead.
more so,
{Nitrats; but the limits of
tin tin.
this
copper copper. {distinction are difficultly
bismuth bismuth. {ascertainable. The older
{chemists were not
antimony antimony.
acquainted
arsenic arsenic. {with any of these salts.
mercury mercury. {

{It is extremely probable that
silver
gold, silver
{and platina only form nitrats,
gold
and cannot subsist
platina {in the state of nitrites.

Table of the Combinations of Azote, completely saturated with
Oxygen, in the state of Nitric Acid, with the Salifiable Bases, in
the order of the affinity with the Acid.

Bases. Names of the resulting neutral salts.
New
Old nomenclature.
nomenclature.
Nitrat
Barytes barytes Nitre, with a base of heavy earth.
of
Nitre, saltpetre. Nitre with base of
Potash potash
potash.
Quadrangular nitre. Nitre with
Soda soda
base of mineral alkali.
Calcareous nitre. Nitre with
Lime lime calcareous base. Mother water of
nitre, or saltpetre.
Magnesian nitre. Nitre with base
Magnesia magnesia
of magnesia.
Ammoniac ammoniac Ammoniacal nitre.
Nitrous alum. Argillaceous nitre.
Argill argill
Nitre with base of earth of alum.
Oxyd of zinc zinc Nitre of zinc.
Nitre of iron. Martial nitre.
iron iron
Nitrated iron.
manganese manganese Nitre of manganese.
cobalt cobalt Nitre of cobalt.
nickel nickel Nitre of nickel.
lead lead Saturnine nitre. Nitre of lead.
tin tin Nitre of tin.

copper copper Nitre of copper or of Venus.
bismuth bismuth Nitre of bismuth.
antimony antimony Nitre of antimony.
arsenic arsenic Arsenical nitre.
mercury mercury Mercurial nitre.
Nitre of silver or luna. Lunar
silver silver
caustic.
gold gold Nitre of gold.
platina platina Nitre of platina.

Sect. XIII.—Observations upon the Nitrous and Nitric Acids,
and their Combinations.

The nitrous and nitric acids are procured from a neutral salt long known in
the arts under the name of saltpetre. This salt is extracted by lixiviation
from the rubbish of old buildings, from the earth of cellars, stables, or
barns, and in general of all inhabited places. In these earths the nitric acid is
usually combined with lime and magnesia, sometimes with potash, and
rarely with argill. As all these salts, excepting the nitrat of potash, attract the
moisture of the air, and consequently would be difficultly preserved,
advantage is taken, in the manufactures of saltpetre and the royal refining
house, of the greater affinity of the nitric acid to potash than these other
bases, by which means the lime, magnesia, and argill, are precipitated, and
all these nitrats are reduced to the nitrat of potash or saltpetre[41].
The nitric acid is procured from this salt by distillation, from three parts of
pure saltpetre decomposed by one part of concentrated sulphuric acid, in a
retort with Woulfe's apparatus, (Pl. IV. fig. 1.) having its bottles half filled
with water, and all its joints carefully luted. The nitrous acid passes over in
form of red vapours surcharged with nitrous gas, or, in other words, not
saturated with oxygen. Part of the acid condenses in the recipient in form of
a dark orange red liquid, while the rest combines with the water in the
bottles. During the distillation, a large quantity of oxygen gas escapes,
owing to the greater affinity of oxygen to caloric, in a high temperature,
than to nitrous acid, though in the usual temperature of the atmosphere this
affinity is reversed. It is from the disengagement of oxygen that the nitric

acid of the neutral salt is in this operation converted into nitrous acid. It is
brought back to the state of nitric acid by heating over a gentle fire, which
drives off the superabundant nitrous gas, and leaves the nitric acid much
diluted with water.
Nitric acid is procurable in a more concentrated state, and with much less
loss, by mixing very dry clay with saltpetre. This mixture is put into an
earthern retort, and distilled with a strong fire. The clay combines with the
potash, for which it has great affinity, and the nitric acid passes over,
slightly impregnated with nitrous gas. This is easily disengaged by heating
the acid gently in a retort, a small quantity of nitrous gas passes over into
the recipient, and very pure concentrated nitric acid remains in the retort.
We have already seen that azote is the nitric radical. If to 20-1/2 parts, by
weight, of azote 43-1/2 parts of oxygen be added, 64 parts of nitrous gas are
formed; and, if to this we join 36 additional parts of oxygen, 100 parts of
nitric acid result from the combination. Intermediate quantities of oxygen
between these two extremes of oxygenation produce different species of
nitrous acid, or, in other words, nitric acid less or more impregnated with
nitrous gas. I ascertained the above proportions by means of decomposition;
and, though I cannot answer for their absolute accuracy, they cannot be far
removed from truth. Mr Cavendish, who first showed by synthetic
experiments that azote is the base of nitric acid, gives the proportions of
azote a little larger than I have done; but, as it is not improbable that he
produced the nitrous acid and not the nitric, that circumstance explains in
some degree the difference in the results of our experiments.
As, in all experiments of a philosophical nature, the utmost possible degree
of accuracy is required, we must procure the nitric acid for experimental
purposes, from nitre which has been previously purified from all foreign
matter. If, after distillation, any sulphuric acid is suspected in the nitric acid,
it is easily separated by dropping in a little nitrat of barytes, so long as any
precipitation takes place; the sulphuric acid, from its greater affinity, attracts
the barytes, and forms with it an insoluble neutral salt, which falls to the
bottom. It may be purified in the same manner from muriatic acid, by
dropping in a little nitrat of silver so long as any precipitation of muriat of
silver is produced. When these two precipitations are finished, distill off

about seven-eighths of the acid by a gentle heat, and what comes over is in
the most perfect degree of purity.
The nitric acid is one of the most prone to combination, and is at the same
time very easily decomposed. Almost all the simple substances, with the
exception of gold, silver, and platina, rob it less or more of its oxygen; some
of them even decompose it altogether. It was very anciently known, and its
combinations have been more studied by chemists than those of any other
acid. These combinations were named nitres by Messrs Macquer and
Beaumé; but we have changed their names to nitrats and nitrites, according
as they are formed by nitric or by nitrous acid, and have added the specific
name of each particular base, to distinguish the several combinations from
each other.

Table of the Combinations of Sulphuric Acid with the Salifiable
Bases, in the order of affinity.

Names of the bases. Resulting compounds.
New nomenclature. Old nomenclature.
Sulphat Heavy spar. Vitriol of heavy
Barytes barytes
of earth.
Vitriolated tartar. Sal de
Potash potash
duobus. Arcanum duplicatam.
Soda soda Glauber's salt.
Selenite, gypsum, calcareous
Lime lime
vitriol.
Epsom salt, sedlitz salt,
Magnesia magnesia
magnesian vitriol.
Ammoniac ammoniac Glauber's secret sal ammoniac.
Argill argill Alum.
White vitriol, goslar vitriol,
Oxyd of zinc zinc
white coperas, vitriol of zinc.
Green coperas, green vitriol,
iron iron
martial vitriol, vitriol of iron.
manganese manganese Vitriol of manganese.
cobalt cobalt Vitriol of cobalt.

nickel nickel Vitriol of nickel.
lead lead Vitriol of lead.
tin tin Vitriol of tin.
Blue coperas, blue vitriol,
copper copper
Roman vitriol, vitriol of copper.
bismuth bismuth Vitriol of bismuth.
antimony antimony Vitriol of antimony.
arsenic arsenic Vitriol of arsenic.
mercury mercury Vitriol of mercury.
silver silver Vitriol of silver.
gold gold Vitriol of gold.
platina platina Vitriol of platina.

Sect. XIV.—Observations upon Sulphuric Acid and its
Combinations.

For a long time this acid was procured by distillation from sulphat of iron,
in which sulphuric acid and oxyd of iron are combined, according to the
process described by Basil Valentine in the fifteenth century; but, in modern
times, it is procured more oeconomically by the combustion of sulphur in
proper vessels. Both to facilitate the combustion, and to assist the
oxygenation of the sulphur, a little powdered saltpetre, nitrat of potash, is
mixed with it; the nitre is decomposed, and gives out its oxygen to the
sulphur, which contributes to its conversion into acid. Notwithstanding this
addition, the sulphur will only continue to burn in close vessels for a limited
time; the combination ceases, because the oxygen is exhausted, and the air
of the vessels reduced almost to pure azotic gas, and because the acid itself
remains long in the state of vapour, and hinders the progress of combustion.
In the manufactories for making sulphuric acid in the large way, the mixture
of nitre and sulphur is burnt in large close built chambers lined with lead,
having a little water at the bottom for facilitating the condensation of the
vapours. Afterwards, by distillation in large retorts with a gentle heat, the
water passes over, slightly impregnated with acid, and the sulphuric acid
remains behind in a concentrated state. It is then pellucid, without any
flavour, and nearly double the weight of an equal bulk of water. This

process would be greatly facilitated, and the combustion much prolonged,
by introducing fresh air into the chambers, by means of several pairs of
bellows directed towards the flame of the sulphur, and by allowing the
nitrous gas to escape through long serpentine canals, in contact with water,
to absorb any sulphuric or sulphurous acid gas it might contain.
By one experiment, Mr Berthollet found that 69 parts of sulphur in
combustion, united with 31 parts of oxygen, to form 100 parts of sulphuric
acid; and, by another experiment, made in a different manner, he calculates
that 100 parts of sulphuric acid consists of 72 parts sulphur, combined with
28 parts of oxygen, all by weight.
This acid, in common with every other, can only dissolve metals when they
have been previously oxydated; but most of the metals are capable of
decomposing a part of the acid, so as to carry off a sufficient quantity of
oxygen, to render themselves soluble in the part of the acid which remains
undecomposed. This happens with silver, mercury, iron, and zinc, in boiling
concentrated sulphuric acid; they become first oxydated by decomposing
part of the acid, and then dissolve in the other part; but they do not
sufficiently disoxygenate the decomposed part of the acid to reconvert it
into sulphur; it is only reduced to the state of sulphurous acid, which, being
volatilised by the heat, flies off in form of sulphurous acid gas.
Silver, mercury, and all the other metals except iron and zinc, are insoluble
in diluted sulphuric acid, because they have not sufficient affinity with
oxygen to draw it off from its combination either with the sulphur, the
sulphurous acid, or the hydrogen; but iron and zinc, being assisted by the
action of the acid, decompose the water, and become oxydated at its
expence, without the help of heat.

Table of the Combinations of the Sulphurous Acid with the
Salifiable Bases, in the order of affinity.

Names of the Bases. Names of the Neutral Salts.
Barytes Sulphite of barytes.
Potash potash.
Soda soda.

Lime lime.
Magnesia magnesia.
Ammoniac ammoniac.
Argill argill.
Oxyd of zinc zinc.
iron iron.
manganese manganese.
cobalt cobalt.
nickel nickel.
lead lead.
tin tin.
copper copper.
bismuth bismuth.
antimony antimony.
arsenic arsenic.
mercury mercury.
silver silver.
gold gold.
platina platina.

Note.—The only one of these salts known to the old chemists was the
sulphite of potash, under the name of Stahl's sulphureous salt. So that,
before our new nomenclature, these compounds must have been named
Stahl's sulphureous salt, having base of fixed vegetable alkali, and so of the
rest.
In this Table we have followed Bergman's order of affinity of the sulphuric
acid, which is the same in regard to the earths and alkalies, but it is not
certain if the order be the same for the metallic oxyds.—A.

Sect. XV.—Observations upon Sulphurous Acid, and its
Combinations.

The sulphurous acid is formed by the union of oxygen with sulphur by a
lesser degree of oxygenation than the sulphuric acid. It is procurable either
by burning sulphur slowly, or by distilling sulphuric acid from silver,

antimony, lead, mercury, or charcoal; by which operation a part of the
oxygen quits the acid, and unites to these oxydable bases, and the acid
passes over in the sulphurous state of oxygenation. This acid, in the
common pressure and temperature of the air, can only exist in form of gas;
but it appears, from the experiments of Mr Clouet, that, in a very low
temperature, it condenses, and becomes fluid. Water absorbs a great deal
more of this gas than of carbonic acid gas, but much less than it does of
muriatic acid gas.
That the metals cannot be dissolved in acids without being previously
oxydated, or by procuring oxygen, for that purpose, from the acids during
solution, is a general and well established fact, which I have perhaps
repeated too often. Hence, as sulphurous acid is already deprived of great
part of the oxygen necessary for forming the sulphuric acid, it is more
disposed to recover oxygen, than to furnish it to the greatest part of the
metals; and, for this reason, it cannot dissolve them, unless previously
oxydated by other means. From the same principle it is that the metallic
oxyds dissolve without effervescence, and with great facility, in sulphurous
acid. This acid, like the muriatic, has even the property of dissolving
metallic oxyds surcharged with oxygen, and consequently insoluble in
sulphuric acid, and in this way forms true sulphats. Hence we might be led
to conclude that there are no metallic sulphites, were it not that the
phenomena which accompany the solution of iron, mercury, and some other
metals, convince us that these metallic substances are susceptible of two
degrees of oxydation, during their solution in acids. Hence the neutral salt
in which the metal is least oxydated must be named sulphite, and that in
which it is fully oxydated must be called sulphat. It is yet unknown whether
this distinction is applicable to any of the metallic sulphats, except those of
iron and mercury.

Table of the Combinations of Phosphorous and Phosphoric
Acids, with the Salifiable Bases, in the Order of Affinity.

Names of the Bases. Names of the Neutral Salts formed by
Phosphorous Acid, Phosphoric Acid.
Phosphites of(B) Phosphats of(C)
Lime lime lime.

Barytes barytes barytes.
Magnesia magnesia magnesia.
Potash potash potash.
Soda soda soda.
Ammoniac ammoniac ammoniac.
Argill argill argill.
Oxyds of(A)
zinc zinc zinc.
iron iron iron.
manganese manganese manganese.
cobalt cobalt cobalt.
nickel nickel nickel.
lead lead lead.
tin tin tin.
copper copper copper.
bismuth bismuth bismuth.
antimony antimony antimony.
arsenic arsenic arsenic.
mercury mercury mercury.
silver silver silver.
gold gold gold.
platina platina platina.

[Note A: The existence of metallic phosphites supposes that metals are
susceptible of solution in phosphoric acid at different degrees of
oxygenation, which is not yet ascertained.—A.]
[Note B: All the phosphites were unknown till lately, and consequently have
not hitherto received names.—A.]
[Note C: The greater part of the phosphats were only discovered of late, and
have not yet been named.—A.]

Sect. XVI.—Observations upon Phosphorous and Phosphoric
Acids, and their Combinations.

Under the article Phosphorus, Part II. Sect. X. we have already given a
history of the discovery of that singular substance, with some observations
upon the mode of its existence in vegetable and animal bodies. The best
method of obtaining this acid in a state of purity is by burning well purified
phosphorus under bell-glasses, moistened on the inside with distilled water;
during combustion it absorbs twice and a half its weight of oxygen; so that
100 parts of phosphoric acid is composed of 28-1/2 parts of phosphorus
united to 71-1/2 parts of oxygen. This acid may be obtained concrete, in
form of white flakes, which greedily attract the moisture of the air, by
burning phosphorus in a dry glass over mercury.
To obtain phosphorous acid, which is phosphorus less oxygenated than in
the state of phosphoric acid, the phosphorus must be burnt by a very slow
spontaneous combustion over a glass-funnel leading into a crystal phial;
after a few days, the phosphorus is found oxygenated, and the phosphorous
acid, in proportion as it forms, has attracted moisture from the air, and
dropped into the phial. The phosphorous acid is readily changed into
phosphoric acid by exposure for a long time to the free air; it absorbs
oxygen from the air, and becomes fully oxygenated.
As phosphorus has a sufficient affinity for oxygen to attract it from the
nitric and muriatic acids, we may form phosphoric acid, by means of these
acids, in a very simple and cheap manner. Fill a tubulated receiver, half full
of concentrated nitric acid, and heat it gently, then throw in small pieces of
phosphorus through the tube, these are dissolved with effervescence and red
fumes of nitrous gas fly off; add phosphorus so long as it will dissolve, and
then increase the fire under the retort to drive off the last particles of nitric
acid; phosphoric acid, partly fluid and partly concrete, remains in the retort.

Table of the Combinations of Carbonic Acid, with the Salifiable
Bases, in the Order of Affinity.

Names of
Resulting Neutral Salts.
Bases
New Nomenclature. Old Nomenclature.
Carbonates
Barytes barytes(A) Aërated or effervescent heavy earth.
of

Chalk, calcareous spar, Aërated
Lime lime
calcareous earth.
Effervescing or aërated fixed
Potash potash
vegetable alkali, mephitis of potash.
Aërated or effervescing fixed
Soda soda
mineral alkali, mephitic soda.
Aërated, effervescing, mild, or
Magnesia magnesia
mephitic magnesia.
Aërated, effervescing, mild, or
Ammoniac ammoniac
mephitic volatile alkali.
Aërated or effervescing argillaceous
Argill argill
earth, or earth of alum.
Oxyds of
zinc zinc Zinc spar, mephitic or aërated zinc.
Sparry iron-ore, mephitic or aërated
iron iron
iron.
manganese manganese Aërated manganese.
cobalt cobalt Aërated cobalt.
nickel nickel Aërated nickel.
lead lead Sparry lead-ore, or aërated lead.
tin tin Aërated tin.
copper copper Aërated copper.
bismuth bismuth Aërated bismuth.
antimony antimony Aërated antimony.
arsenic arsenic Aërated arsenic.
mercury mercury Aërated mercury.
silver silver Aërated silver.
gold gold Aërated gold.
platina platina Aërated platina.

[Note A: As these salts have only been understood of late, they have not,
properly speaking, any old names. Mr Morveau, in the First Volume of the
Encyclopedia, calls them Mephites; Mr Bergman gives them the name of
aërated; and Mr de Fourcroy, who calls the carbonic acid chalky acid, gives
them the name of chalks.—A]

Sect. XVII.—Observations upon Carbonic Acid, and its
Combinations.

Of all the known acids, the carbonic is the most abundant in nature; it exists
ready formed in chalk, marble, and all the calcareous stones, in which it is
neutralized by a particular earth called lime. To disengage it from this
combination, nothing more is requisite than to add some sulphuric acid, or
any other which has a stronger affinity for lime; a brisk effervescence
ensues, which is produced by the disengagement of the carbonic acid which
assumes the state of gas immediately upon being set free. This gas,
incapable of being condensed into the solid or liquid form by any degree of
cold or of pressure hitherto known, unites to about its own bulk of water,
and thereby forms a very weak acid. It may likewise be obtained in great
abundance from saccharine matter in fermentation, but is then contaminated
by a small portion of alkohol which it holds in solution.
As charcoal is the radical of this acid, we may form it artificially, by
burning charcoal in oxygen gas, or by combining charcoal and metallic
oxyds in proper proportions; the oxygen of the oxyd combines with the
charcoal, forming carbonic acid gas, and the metal being left free, recovers
its metallic or reguline form.
We are indebted for our first knowledge of this acid to Dr Black, before
whose time its property of remaining always in the state of gas had made it
to elude the researches of chemistry.
It would be a most valuable discovery to society, if we could decompose
this gas by any cheap process, as by that means we might obtain, for
economical purposes, the immense store of charcoal contained in
calcareous earths, marbles, limestones, &c. This cannot be effected by
single affinity, because, to decompose the carbonic acid, it requires a
substance as combustible as charcoal itself, so that we should only make an
exchange of one combustible body for another not more valuable; but it
may possibly be accomplished by double affinity, since this process is so
readily performed by Nature, during vegetation, from the most common
materials.

Table of the Combinations of Muriatic Acid, with the Salifiable
Bases, in the Order of Affinity.

Names of the Resulting Neutral
bases. Salts.
New nomenclature. Old nomenclature.
Barytes. Muriat of
barytes Sea-salt, having base of heavy earth.
Febrifuge salt of Sylvius: Muriated
Potash potash
vegetable fixed alkali.
Soda soda Sea-salt.
Lime lime Muriated lime. Oil of lime.
Marine Epsom salt. Muriated
Magnesia magnesia
magnesia.
Ammoniac ammoniac Sal ammoniac.
{Muriated alum, sea-salt with base of
Argill argill
earth of alum.
Oxyd of
zinc zinc Sea-salt of, or muriatic zinc.
iron iron Salt of iron, Martial sea-salt.
manganese manganese Sea-salt of manganese.
cobalt cobalt Sea-salt of cobalt.
nickel nickel Sea-salt of nickel.
lead lead Horny-lead. Plumbum corneum.
smoaking of tin Smoaking liquor of Libavius. Solid
tin
solid of tin butter of tin.
copper copper Sea-salt of copper.
bismuth bismuth Sea-salt of bismuth.
antimony antimony Sea-salt of antimony.
arsenic arsenic Sea-salt of arsenic.
Sweet sublimate of mercury,
{sweet of mercury
calomel, aquila alba.
mercury
{corrosive of
Corrosive sublimate of mercury.
mercury

Horny silver, argentum corneum,
silver silver
luna cornea.
gold gold Sea-salt of gold.
platina platina Sea-salt of platina.

Table Of the Combinations of Oxygenated Muriatic Acid, with
the Salifiable Bases, in the Order of Affinity.

Names of the Bases. Names of the Neutral Salts by the new Nomenclature.
Oxygenated muriat of
Barytes barytes.
Potash potash.
Soda soda.
Lime lime.
Magnesia magnesia.
Argill argill.
Oxyd of
zinc zinc.
iron iron.
manganese manganese.
cobalt cobalt.
nickel nickel.
lead lead.
tin tin.
copper copper.
bismuth bismuth.
antimony antimony.
arsenic arsenic.
mercury mercury.
silver silver.
gold gold.
platina platina.

This order of salts, entirely unknown to the ancient chemists, was
discovered in 1786 by Mr Berthollet.—A.

Sect. XIX.—Observations upon Muriatic and Oxygenated
Muriatic Acids, and their Combinations.

Muriatic acid is very abundant in the mineral kingdom naturally combined
with different salifiable bases, especially with soda, lime, and magnesia. In
sea-water, and the water of several lakes, it is combined with these three
bases, and in mines of rock-salt it is chiefly united to soda. This acid does
not appear to have been hitherto decomposed in any chemical experiment;
so that we have no idea whatever of the nature of its radical, and only
conclude, from analogy with the other acids, that it contains oxygen as its
acidifying principle. Mr Berthollet suspects the radical to be of a metallic
nature; but, as Nature appears to form this acid daily, in inhabited places, by
combining miasmata with aëriform fluids, this must necessarily suppose a
metallic gas to exist in the atmosphere, which is certainly not impossible,
but cannot be admitted without proof.
The muriatic acid has only a moderate adherence to the salifiable bases, and
can readily be driven from its combination with these by sulphuric acid.
Other acids, as the nitric, for instance, may answer the same purpose; but
nitric acid being volatile, would mix, during distillation, with the muriatic.
About one part of sulphuric acid is sufficient to decompose two parts of
decrepitated sea-salt. This operation is performed in a tubulated retort,
having Woulfe's apparatus, (Pl. IV. Fig. 1.), adapted to it. When all the
junctures are properly lured, the sea-salt is put into the retort through the
tube, the sulphuric acid is poured on, and the opening immediately closed
with its ground crystal stopper. As the muriatic acid can only subsist in the
gaseous form in the ordinary temperature, we could not condense it without
the presence of water. Hence the use of the water with which the bottles in
Woulfe's apparatus are half filled; the muriatic acid gas, driven off from the
sea-salt in the retort, combines with the water, and forms what the old
chemists called smoaking spirit of salt, or Glauber's spirit of sea-salt, which
we now name muriatic acid.

The acid obtained by the above process is still capable of combining with a
farther dose of oxygen, by being distilled from the oxyds of manganese,
lead, or mercury, and the resulting acid, which we name oxygenated
muriatic acid, can only, like the former, exist in the gasseous form, and is
absorbed, in a much smaller quantity by water. When the impregnation of
water with this gas is pushed beyond a certain point, the superabundant acid
precipitates to the bottom of the vessels in a concrete form. Mr Berthollet
has shown that this acid is capable of combining with a great number of the
salifiable bases; the neutral salts which result from this union are
susceptible of deflagrating with charcoal, and many of the metallic
substances; these deflagrations are very violent and dangerous, owing to the
great quantity of caloric which the oxygen carries alongst with it into the
composition of oxygenated muriatic acid.

Table of the Combinations of Nitro-muriatic Acid with the
Salifiable Bases, in the Order of Affinity, so far as is known.

Names of the Bases. Names of the Neutral Salts.
Argill Nitro-muriat of argill.
Ammoniac ammoniac.
Oxyd of
antimony antimony.
silver silver.
arsenic arsenic.
Barytes barytes.
Oxyd of bismuth bismuth.
Lime lime.
Oxyd of
cobalt cobalt.
copper copper.
tin tin.
iron iron.
Magnesia magnesia.
Oxyd of
manganese manganese.

mercury mercury.
molybdena molybdena.
nickel nickel.
gold gold.
platina platina.
lead lead.
Potash potash.
Soda soda.
Oxyd of
tungstein tungstein.
zinc zinc.

Note.—Most of these combinations, especially those with the earths and
alkalies, have been little examined, and we are yet to learn whether they
form a mixed salt in which the compound radical remains combined, or if
the two acids separate, to form two distinct neutral salts.—A.

Sect. XX.—Observations upon the Nitro-Muriatic Acid, and its
Combinations.

The nitro-muriatic acid, formerly called aqua regia, is formed by a mixture
of nitric and muriatic acids; the radicals of these two acids combine
together, and form a compound base, from which an acid is produced,
having properties peculiar to itself, and distinct from those of all other
acids, especially the property of dissolving gold and platina.
In dissolutions of metals in this acid, as in all other acids, the metals are
first oxydated by attracting a part of the oxygen from the compound radical.
This occasions a disengagement of a particular species of gas not hitherto
described, which may be called nitro-muriatic gas; it has a very
disagreeable smell, and is fatal to animal life when respired; it attacks iron,
and causes it to rust; it is absorbed in considerable quantity by water, which
thereby acquires some slight characters of acidity. I had occasion to make
these remarks during a course of experiments upon platina, in which I
dissolved a considerable quantity of that metal in nitro-muriatic acid.

I at first suspected that, in the mixture of nitric and muriatic acids, the latter
attracted a part of the oxygen from the former, and became converted into
oxygenated muriatic acid, which gave it the property of dissolving gold; but
several facts remain inexplicable upon this supposition. Were it so, we must
be able to disengage nitrous gas by heating this acid, which however does
not sensibly happen. From these considerations, I am led to adopt the
opinion of Mr Berthollet, and to consider nitro-muriatic acid as a single
acid, with a compound base or radical.

Table of the Combinations of Fluoric Acid, with the Salifiable
Bases, in the Order of Affinity.

Names of the Bases. Names of the Neutral Salts.
Lime Fluat of lime.
Barytes barytes.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Oxyd of
zinc zinc.
manganese manganese.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
arsenic arsenic.
bismuth bismuth.
mercury mercury.
silver silver.
gold gold.
platina platina.
And by the dry way,

Argill Fluat of argill.

Note.—These combinations were entirely unknown to the old chemists, and
consequently have no names in the old nomenclature.—A.

Sect. XXI.—Observations upon the Fluoric Acid, and its
Combinations.

Fluoric exists ready formed by Nature in the fluoric spars[42], combined
with calcareous earth, so as to form an insoluble neutral salt. To obtain it
disengaged from that combination, fluor spar, or fluat of lime, is put into a
leaden retort, with a proper quantity of sulphuric acid, a recipient likewise
of lead, half full of water, is adapted, and fire is applied to the retort. The
sulphuric acid, from its greater affinity, expels the fluoric acid which passes
over and is absorbed by the water in the receiver. As fluoric acid is naturally
in the gasseous form in the ordinary temperature, we can receive it in a
pneumato-chemical apparatus over mercury. We are obliged to employ
metallic vessels in this process, because fluoric acid dissolves glass and
silicious earth, and even renders these bodies volatile, carrying them over
with itself in distillation in the gasseous form.
We are indebted to Mr Margraff for our first acquaintance with this acid,
though, as he could never procure it free from combination with a
considerable quantity of silicious earth, he was ignorant of its being an acid
sui generis. The Duke de Liancourt, under the name of Mr Boulanger,
considerably increased our knowledge of its properties; and Mr Scheele
seems to have exhausted the subject. The only thing remaining is to
endeavour to discover the nature of the fluoric radical, of which we cannot
hitherto form any ideas, as the acid does not appear to have been
decomposed in any experiment. It is only by means of compound affinity
that experiments ought to be made with this view, with any probability of
success.

Table of the Combinations of Boracic Acid, with the Salifiable
Bases, in the Order of Affinity.

Bases. Neutral Salts.

Lime Borat of lime.
Barytes barytes.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Oxyd of
zinc zinc.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
mercury mercury.
Argill argill.

Note.—Most of these combinations were neither known nor named by the
old chemists. The boracic acid was formerly called sedative salt, and its
compounds borax, with base of fixed vegetable alkali, &c.—A.

Sect. XXII.—Observations upon Boracic Add and its
Combinations.

This is a concrete acid, extracted from a salt procured from India called
borax or tincall. Although borax has been very long employed in the arts,
we have as yet very imperfect knowledge of its origin, and of the methods
by which it is extracted and purified; there is reason to believe it to be a
native salt, found in the earth in certain parts of the east, and in the water of
some lakes. The whole trade of borax is in the hands of the Dutch, who
have been exclusively possessed of the art of purifying it till very lately,
that Messrs L'Eguillier of Paris have rivalled them in the manufacture; but
the process still remains a secret to the world.
By chemical analysis we learn that borax is a neutral salt with excess of
base, consisting of soda, partly saturated with a peculiar acid long called

Homberg's sedative salt, now the boracic acid. This acid is found in an
uncombined state in the waters of certain lakes. That of Cherchiais in Italy
contains 94-1/2 grains in each pint of water.
To obtain boracic acid, dissolve some borax in boiling water, filtrate the
solution, and add sulphuric acid, or any other having greater affinity to soda
than the boracic acid; this latter acid is separated, and is procured in a
crystalline form by cooling. This acid was long considered as being formed
during the process by which it is obtained, and was consequently supposed
to differ according to the nature of the acid employed in separating it from
the soda; but it is now universally acknowledged that it is identically the
same acid, in whatever way procured, provided it be properly purified from
mixture of other acids, by warning, and by repeated solution and
cristallization. It is soluble both in water and alkohol, and has the property
of communicating a green colour to the flame of that spirit. This
circumstance led to a suspicion of its containing copper, which is not
confirmed by any decisive experiment. On the contrary, if it contain any of
that metal, it must only be considered as an accidental mixture. It combines
with the salifiable bases in the humid way; and though, in this manner, it is
incapable of dissolving any of the metals directly, this combination is
readily affected by compound affinity.
The Table presents its combinations in the order of affinity in the humid
way; but there is a considerable change in the order when we operate via
sicca; for, in that case, argill, though the last in our list, must be placed
immediately after soda.
The boracic radical is hitherto unknown; no experiments having as yet been
able to decompose the acid; We conclude, from analogy with the other
acids, that oxygen exists in its composition as the acidifying principle.

Table of the Combinations of Arseniac Acid, with the Salifiable
Bases, in the Order of Affinity.

Bases. Neutral Salts.
Lime Arseniat of lime.
Barytes barytes.

Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Oxyd of
zinc zinc.
manganese manganese.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
bismuth bismuth.
mercury mercury.
antimony antimony.
silver silver.
gold gold.
platina platina.
Argill argill.

Note.—This order of salts was entirely unknown to the antient chemists. Mr
Macquer, in 1746, discovered the combinations of arseniac acid with potash
and soda, to which he gave the name of arsenical neutral salts.—A.

Sect. XXIII.—Observations upon Arseniac Acid, and its
Combinations.

In the Collections of the Academy for 1746, Mr Macquer shows that, when
a mixture of white oxyd of arsenic and nitre are subjected to the action of a
strong fire, a neutral salt is obtained, which he calls neutral salt of arsenic.
At that time, the cause of this singular phenomenon, in which a metal acts
the part of an acid, was quite unknown; but more modern experiments teach
that, during this process, the arsenic becomes oxygenated, by carrying off
the oxygen of the nitric acid; it is thus converted into a real acid, and

combines with the potash. There are other methods now known for
oxygenating arsenic, and obtaining its acid free from combination. The
most simple and most effectual of these is as follows: Dissolve white oxyd
of arsenic in three parts, by weight, of muriatic acid; to this solution, in a
boiling state, add two parts of nitric acid, and evaporate to dryness. In this
process the nitric acid is decomposed, its oxygen unites with the oxyd of
arsenic, and converts it into an acid, and the nitrous radical flies off in the
state of nitrous gas; whilst the muriatic acid is converted by the heat into
muriatic acid gas, and may be collected in proper vessels. The arseniac acid
is entirely freed from the other acids employed during the process by
heating it in a crucible till it begins to grow red; what remains is pure
concrete arseniac acid.
Mr Scheele's process, which was repeated with great success by Mr
Morveau, in the laboratory at Dijon, is as follows: Distil muriatic acid from
the black oxyd of manganese, this converts it into oxygenated muriatic acid,
by carrying off the oxygen from the manganese, receive this in a recipient
containing white oxyd of arsenic, covered by a little distilled water; the
arsenic decomposes the oxygenated muriatic acid, by carrying off its
supersaturation of oxygen, the arsenic is converted into arseniac acid, and
the oxygenated muriatic acid is brought back to the state of common
muriatic acid. The two acids are separated by distillation, with a gentle heat
increased towards the end of the operation, the muriatic acid passes over,
and the arseniac acid remains behind in a white concrete form.
The arseniac acid is considerably less volatile than white oxyd of arsenic; it
often contains white oxyd of arsenic in solution, owing to its not being
sufficiently oxygenated; this is prevented by continuing to add nitrous acid,
as in the former process, till no more nitrous gas is produced. From all these
observations I would give the following definition of arseniac acid. It is a
white concrete metallic acid, formed by the combination of arsenic with
oxygen, fixed in a red heat, soluble in water, and capable of combining with
many of the salifiable bases.

Sect. XXIV.—Observations upon Molybdic Acid, and its
Combinations with Acidifiable Bases[43].

Molybdena is a particular metallic body, capable of being oxygenated, so
far as to become a true concrete acid[44]. For this purpose, one part ore of
molybdena, which is a natural sulphuret of that metal, is put into a retort,
with five or six parts nitric acid, diluted with a quarter of its weight of
water, and heat is applied to the retort; the oxygen of the nitric acid acts
both upon the molybdena and the sulphur, converting the one into
molybdic, and the other into sulphuric acid; pour on fresh quantities of
nitric acid so long as any red fumes of nitrous gas escape; the molydbena is
then oxygenated as far as is possible, and is found at the bottom of the retort
in a pulverulent form, resembling chalk. It must be washed in warm water,
to separate any adhering particles of sulphuric acid; and, as it is hardly
soluble, we lose very little of it in this operation. All its combinations with
salifiable bases were unknown to the ancient chemists.

Table of the Combinations of Tungstic Acid with the Salifiable
Bases.

Bases. Neutral Salts.
Lime Tungstat of lime.
Barytes barytes.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Argill argill.
Oxyd of antimony(A), &c. antimony(B), &c.

[Note A: The combinations with metallic oxyds were set down by Mr
Lavoisier in alphabetical order; their order of affinity being unknown, I
have omitted them, as serving no purpose.—E.]
[Note B: All these salts were unknown to the ancient chemists.—A.]

Sect. XXV.—Observations upon Tungstic Acid, and its
Combinations.

Tungstein is a particular metal, the ore of which has frequently been
confounded with that of tin. The specific gravity of this ore is to water as 6
to 1; in its form of cristallization it resembles the garnet, and varies in
colour from a pearl-white to yellow and reddish; it is found in several parts
of Saxony and Bohemia. The mineral called Wolfram, which is frequent in
the mines of Cornwal, is likewise an ore of this metal. In all these ores the
metal is oxydated; and, in some of them, it appears even to be oxygenated
to the state of acid, being combined with lime into a true tungstat of lime.
To obtain the acid free, mix one part of ore of tungstein with four parts of
carbonat of potash, and melt the mixture in a crucible, then powder and
pour on twelve parts of boiling water, add nitric acid, and the tungstic acid
precipitates in a concrete form. Afterwards, to insure the complete
oxygenation of the metal, add more nitric acid, and evaporate to dryness,
repeating this operation so long as red fumes of nitrous gas are produced.
To procure tungstic acid perfectly pure, the fusion of the ore with carbonat
of potash must be made in a crucible of platina, otherwise the earth of the
common crucibles will mix with the products, and adulterate the acid.

Table of the Combinations of Tartarous Acid, with the Salifiable
Bases, in the Order of Affinity.

Bases. Neutral Salts.
Lime Tartarite of lime.
Barytes barytes.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Argill argill.
Oxyd of
zinc zinc.
iron iron.
manganese manganese.
cobalt cobalt.
nickel nickel.

lead lead.
tin tin.
copper copper.
bismuth bismuth.
antimony antimony.
arsenic arsenic.
silver silver.
mercury mercury.
gold gold.
platina platina.

Sect. XXVI.—Observations upon Tartarous Acid, and its
Combinations.

Tartar, or the concretion which fixes to the inside of vessels in which the
fermentation of wine is completed, is a well known salt, composed of a
peculiar acid, united in considerable excess to potash. Mr Scheele first
pointed out the method of obtaining this acid pure. Having observed that it
has a greater affinity to lime than to potash, he directs us to proceed in the
following manner. Dissolve purified tartar in boiling water, and add a
sufficient quantity of lime till the acid be completely saturated. The tartarite
of lime which is formed, being almost insoluble in cold water, falls to the
bottom, and is separated from the solution of potash by decantation; it is
afterwards washed in cold water, and dried; then pour on some sulphuric
acid, diluted with eight or nine parts of water, digest for twelve hours in a
gentle heat, frequently stirring the mixture; the sulphuric acid combines
with the lime, and the tartarous acid is left free. A small quantity of gas, not
hitherto examined, is disengaged during this process. At the end of twelve
hours, having decanted off the clear liquor, wash the sulphat of lime in cold
water, which add to the decanted liquor, then evaporate the whole, and the
tartarous acid is obtained in a concrete form. Two pounds of purified tartar,
by means of from eight to ten ounces of sulphuric acid, yield about eleven
ounces of tartarous acid.
As the combustible radical exists in excess, or as the acid from tartar is not
fully saturated with oxygen, we call it tartarous acid, and the neutral salts

formed by its combinations with salifiable bases tartarites. The base of the
tartarous acid is a carbono-hydrous or hydro-carbonous radical, less
oxygenated than in the oxalic acid; and it would appear, from the
experiments of Mr Hassenfratz, that azote enters into the composition of the
tartarous radical, even in considerable quantity. By oxygenating the
tartarous acid, it is convertible into oxalic, malic, and acetous acids; but it is
probable the proportions of hydrogen and charcoal in the radical are
changed during these conversions, and that the difference between these
acids does not alone consist in the different degrees of oxygenation.
The tartarous acid is susceptible of two degrees of saturation in its
combinations with the fixed alkalies; by one of these a salt is formed with
excess of acid, improperly called cream of tartar, which in our new
nomenclature is named acidulous tartarite of potash; by a second or equal
degree of saturation a perfectly neutral salt is formed, formerly called
vegetable salt, which we name tartarite of potash. With soda this acid
forms tartarite of soda, formerly called sal de Seignette, or sal polychrest of
Rochell.

Sect. XXVII.—Observations upon Malic Acid, and its
Combinations with the Salifiable Bases[45].

The malic acid exists ready formed in the sour juice of ripe and unripe
apples, and many other fruits, and is obtained as follows: Saturate the juice
of apples with potash or soda, and add a proper proportion of acetite of lead
dissolved in water; a double decomposition takes place, the malic acid
combines with the oxyd of lead and precipitates, being almost insoluble,
and the acetite of potash or soda remains in the liquor. The malat of lead
being separated by decantation, is washed with cold water, and some dilute
sulphuric acid is added; this unites with the lead into an insoluble sulphat,
and the malic acid remains free in the liquor.
This acid, which is found mixed with citric and tartarous acid in a great
number of fruits, is a kind of medium between oxalic and acetous acids
being more oxygenated than the former, and less so than the latter. From
this circumstance, Mr Hermbstadt calls it imperfect vinegar; but it differs

likewise from acetous acid, by having rather more charcoal, and less
hydrogen, in the composition of its radical.
When an acid much diluted has been used in the foregoing process, the
liquor contains oxalic as well as malic acid, and probably a little tartarous,
these are separated by mixing lime-water with the acids, oxalat, tartarite,
and malat of lime are produced; the two former, being insoluble, are
precipitated, and the malat of lime remains dissolved; from this the pure
malic acid is separated by the acetite of lead, and afterwards by sulphuric
acid, as directed above.

Table of the Combinations of Citric Acid, with the Salifiable
Bases, in the Order of Affinity(A).

Bases. Neutral Salts.
Barytes Citrat of barytes.
Lime lime.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Oxyd of
zinc zinc.
manganese manganese.
iron iron.
lead lead.
cobalt cobalt.
copper copper.
arsenic arsenic.
mercury mercury.
antimony antimony.
silver silver.
gold gold.
platina platina.
Argill argill.

[Note A: These combinations were unknown to the ancient chemists. The
order of affinity of the salifiable bases with this acid was determined by Mr
Bergman and by Mr de Breney of the Dijon Academy.—A.]

Sect. XXVIII.—Observations upon Citric Acid, and its
Combinations.

The citric acid is procured by expression from lemons, and is found in the
juices of many other fruits mixed with malic acid. To obtain it pure and
concentrated, it is first allowed to depurate from the mucous part of the fruit
by long rest in a cool cellar, and is afterwards concentrated by exposing it to
the temperature of 4 or 5 degrees below Zero, from 21° to 23° of
Fahrenheit, the water is frozen, and the acid remains liquid, reduced to
about an eighth part of its original bulk. A lower degree of cold would
occasion the acid to be engaged amongst the ice, and render it difficultly
separable. This process was pointed out by Mr Georgius.
It is more easily obtained by saturating the lemon-juice with lime, so as to
form a citrat of lime, which is insoluble in water; wash this salt, and pour on
a proper quantity of sulphuric acid; this forms a sulphat of lime, which
precipitates and leaves the citric acid free in the liquor.

Table of the Combinations of Pyro-lignous Acid with the
Salifiable Bases, in the Order of Affinity(A).

Bases. Neutral Salts.
Lime Pyro-mucite of lime.
Barytes barytes.
Potash potash.
Soda soda.
Magnesia magnesia.
Ammoniac ammoniac.
Oxyd of
zinc zinc.
manganese manganese.
iron iron.

lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
arsenic arsenic.
bismuth bismuth.
mercury mercury.
antimony antimony.
silver silver.
gold gold.
platina platina.
Argill argill.

[Note A: The above affinities were determined by Messrs de Morveau and
EloI Boursier de Clervaux. These combinations were entirely unknown till
lately.—A.]

Sect. XXIX.—Observations upon Pyro-lignous Acid, and its
Combinations.

The ancient chemists observed that most of the woods, especially the more
heavy and compact ones, gave out a particular acid spirit, by distillation, in
a naked fire; but, before Mr Goetling, who gives an account of his
experiments upon this subject in Crell's Chemical Journal for 1779, no one
had ever made any inquiry into its nature and properties. This acid appears
to be the same, whatever be the wood it is procured from. When first
distilled, it is of a brown colour, and considerably impregnated with
charcoal and oil; it is purified from these by a second distillation. The pyro-
lignous radical is chiefly composed of hydrogen and charcoal.

Sect. XXX.—Observations upon Pyro-tartarous Acid, and its
Combinations with the Salifiable Bases[46].

The name of Pyro-tartarous acid is given to a dilute empyreumatic acid
obtained from purified acidulous tartarite of potash by distillation in a
naked fire. To obtain it, let a retort be half filled with powdered tartar, adapt
a tubulated recipient, having a bent tube communicating with a bell-glass in
a pneumato-chemical apparatus; by gradually raising the fire under the
retort, we obtain the pyro-tartarous acid mixed with oil, which is separated
by means of a funnel. A vast quantity of carbonic acid gas is disengaged
during the distillation. The acid obtained by the above process is much
contaminated with oil, which ought to be separated from it. Some authors
advise to do this by a second distillation; but the Dijon academicians inform
us, that this is attended with great danger from explosions which take place
during the process.

Table of the Combinations of Pyro-mucous Acid, with the
Salifiable Bases, in the Order of Affinity(A).

Bases. Neutral Salts.
Potash Pyro-mucite of potash.
Soda soda.
Barytes barytes.
Lime lime.
Magnesia magnesia.
Ammoniac ammoniac.
Argill argill.
Oxyd of
zinc zinc.
manganese manganese.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
arsenic arsenic.
bismuth bismuth.

antimony antimony.

[Note A: All these combinations were unknown to the ancient chemists.—
A.]

Sect. XXXI.—Observations upon Pyro-mucous Acid, and its
Combinations.

This acid is obtained by distillation in a naked fire from sugar, and all the
saccharine bodies; and, as these substances swell greatly in the fire, it is
necessary to leave seven-eighths of the retort empty. It is of a yellow colour,
verging to red, and leaves a mark upon the skin, which will not remove but
alongst with the epidermis. It may be procured less coloured, by means of a
second distillation, and is concentrated by freezing, as is directed for the
citric acid. It is chiefly composed of water and oil slightly oxygenated, and
is convertible into oxalic and malic acids by farther oxygenation with the
nitric acid.
It has been pretended that a large quantity of gas is disengaged during the
distillation of this acid, which is not the case if it be conducted slowly, by
means of moderate heat.

Table of the Combinations of the Oxalic Acid, with the Salifiable
Bases, in the Order of Affinity(A).

Bases. Neutral Salts.
Lime Oxalat of lime.
Barytes barytes.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Argill argill.
Oxyd of
zinc zinc.
iron iron.

manganese manganese.
cobalt cobalt.
nickel nickel.
lead lead.
copper copper.
bismuth bismuth.
antimony antimony.
arsenic arsenic.
mercury mercury.
silver silver.
gold gold.
platina platina.

[Note A: All unknown to the ancient chemists.—A.]

Sect. XXXII.—Observations upon Oxalic Acid, and its
Combinations.

The oxalic acid is mostly prepared in Switzerland and Germany from the
expressed juice of sorrel, from which it cristallizes by being left long at rest;
in this state it is partly saturated with potash, forming a true acidulous
oxalat of potash, or salt with excess of acid. To obtain it pure, it must be
formed artificially by oxygenating sugar, which seems to be the true oxalic
radical. Upon one part of sugar pour six or eight parts of nitric acid, and
apply a gentle heat; a considerable effervescence takes place, and a great
quantity of nitrous gas is disengaged; the nitric acid is decomposed, and its
oxygen unites to the sugar: By allowing the liquor to stand at rest, cristals of
pure oxalic acid are formed, which must be dried upon blotting paper, to
separate any remaining portions of nitric acid; and, to ensure the purity of
the acid, dissolve the cristals in distilled water, and cristallize them afresh.

Neutral Names of the resulting neutral salts according to
Bases.
salts. the old nomenclature.
Acetite of Unknown to the ancients. Discovered by Mr de
Barytes
barytes Morveau, who calls it barotic acéte.

Secret terra foliata tartari of Muller. Arcanum
tartari of Basil Valentin and Paracelsus. Purgative
Potash —— potash magistery of tartar of Schroëder. Essential salt of
wine of Zwelfer. Regenerated tartar of Tachenius.
Diuretic salt of Sylvius and Wilson.
Foliated earth with base of mineral alkali. Mineral
Soda —— soda or crystallisable foliated earth. Mineral acetous
salt.
Salt of chalk, coral, or crabs eyes; mentioned by
Lime —— lime
Hartman.
——
Magnesia First mentioned by Mr Wenzel.
magnesia
——
Ammoniac Spiritus Mindereri. Ammoniacal acetous salt.
ammoniac
Oxyd of Known to Glauber, Schwedemberg, Respour,
—— zinc
zinc Pott, de Lassone, and Wenzel, but not named.
—— ——
Unknown to the ancients.
manganese manganese
Martial vinegar. Described by Monnet, Wenzel,
—— iron —— iron
and the Duke d'Ayen.
—— lead —— lead Sugar, vinegar, and salt of lead or Saturn.
Known to Lemery, Margraff, Monnet,
—— tin —— tin
Weslendorf, and Wenzel, but not named.
—— cobalt —— cobalt Sympathetic ink of Mr Cadet.
—— —— Verdigris, crystals of verditer, verditer, distilled
copper copper verdigris, crystals of Venus or of copper.
—— nickel —— nickel Unknown to the ancients.
—— —— Arsenico-acetous fuming liquor, liquid
arsenic arsenic phosphorus of Mr Cadet.
Sugar of bismuth of Mr Geoffroi. Known to
—— ——
Gellert, Pott, Weslendorf, Bergman, and de
bismuth bismuth
Morveau.
Mercurial foliated earth, Keyser's famous
—— —— antivenereal remedy. Mentioned by Gebaver in
mercury mercury 1748; known to Helot, Margraff, Baumé,
Bergman, and de Morveau.

—— ——
Unknown.
antimony antimony
Described by Margraff, Monnet, and Wenzel;
—— silver —— silver
unknown to the ancients.
Little known, mentioned by Schroëder and
—— gold —— gold
Juncker.
—— ——
Unknown.
platina platina
According to Mr Wenzel, vinegar dissolves only a
Argill —— argill
very small proportion of argill.

From the liquor remaining after the first cristallization of the oxalic acid we
may obtain malic acid by refrigeration: This acid is more oxygenated than
the oxalic; and, by a further oxygenation, the sugar is convertible into
acetous acid, or vinegar.
The oxalic acid, combined with a small quantity of soda or potash, has the
property, like the tartarous acid, of entering into a number of combinations
without suffering decomposition: These combinations form triple salts, or
neutral salts with double bases, which ought to have proper names. The salt
of sorrel, which is potash having oxalic acid combined in excess, is named
acidulous oxalat of potash in our new nomenclature.
The acid procured from sorrel has been known to chemists for more than a
century, being mentioned by Mr Duclos in the Memoirs of the Academy for
1688, and was pretty accurately described by Boerhaave; but Mr Scheele
first showed that it contained potash, and demonstrated its identity with the
acid formed by the oxygenation of sugar.

Sect. XXXIII.—Observations upon Acetous Acid, and its
Combinations.

This acid is composed of charcoal and hydrogen united together, and
brought to the state of an acid by the addition of oxygen; it is consequently
formed by the same elements with the tartarous oxalic, citric, malic acids,
and others, but the elements exist in different proportions in each of these;
and it would appear that the acetous acid is in a higher state of oxygenation

than these other acids. I have some reason to believe that the acetous radical
contains a small portion of azote; and, as this element is not contained in the
radicals of any vegetable acid except the tartarous, this circumstance is one
of the causes of difference. The acetous acid, or vinegar, is produced by
exposing wine to a gentle heat, with the addition of some ferment: This is
usually the ley, or mother, which has separated from other vinegar during
fermentation, or some similar matter. The spiritous part of the wine, which
consists of charcoal and hydrogen, is oxygenated, and converted into
vinegar: This operation can only take place with free access of air, and is
always attended by a diminution of the air employed in consequence of the
absorption of oxygen; wherefore, it ought always to be carried on in vessels
only half filled with the vinous liquor submitted to the acetous
fermentation. The acid formed during this process is very volatile, is mixed
with a large proportion of water, and with many foreign substances; and, to
obtain it pure, it is distilled in stone or glass vessels by a gentle fire. The
acid which passes over in distillation is somewhat changed by the process,
and is not exactly of the same nature with what remains in the alembic, but
seems less oxygenated: This circumstance has not been formerly observed
by chemists.
Distillation is not sufficient for depriving this acid of all its unnecessary
water; and, for this purpose, the best way is by exposing it to a degree of
cold from 4° to 6° below the freezing point, from 19° to 23° of Fahrenheit;
by this means the aqueous part becomes frozen, and leaves the acid in a
liquid state, and considerably concentrated. In the usual temperature of the
air, this acid can only exist in the gasseous form, and can only be retained
by combination with a large proportion of water. There are other chemical
processes for obtaining the acetous acid, which consist in oxygenating the
tartarous, oxalic, or malic acids, by means of nitric acid; but there is reason
to believe the proportions of the elements of the radical are changed during
this process. Mr Hassenfratz is at present engaged in repeating the
experiments by which these conversions are said to be produced.
The combinations of acetous acid with the various salifiable bases are very
readily formed; but most of the resulting neutral salts are not cristallizable,
whereas those produced by the tartarous and oxalic acids are, in general,
hardly soluble. Tartarite and oxalat of lime are not soluble in any sensible
degree: The malats are a medium between the oxalats and acetites, with

respect to solubility, and the malic acid is in the middle degree of saturation
between the oxalic and acetous acids. With this, as with all the acids, the
metals require to be oxydated previous to solution.
The ancient chemists knew hardly any of the salts formed by the
combinations of acetous acid with the salifiable bases, except the acetites of
potash, soda, ammoniac, copper, and lead. Mr Cadet discovered the acetite
of arsenic[47]; Mr Wenzel, the Dijon academicians Mr de Lassone, and Mr
Proust, made us acquainted with the properties of the other acetites. From
the property which acetite of potash possesses, of giving out ammoniac in
distillation, there is some reason to suppose, that, besides charcoal and
hydrogen, the acetous radical contains a small proportion of azote, though it
is not impossible but the above production of ammoniac may be occasioned
by the decomposition of the potash.

Table of the Combinations of Acetic Acid with the Salifiable
Bases, in the order of affinity.

Bases. Neutral Salts.
Barytes Acetat of barytes.
Potash potash.
Soda soda.
Lime lime.
Magnesia magnesia.
Ammoniac ammoniac.
Oxyd of zinc zinc.
manganese manganese.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
arsenic arsenic.
bismuth bismuth.

mercury mercury.
antimony antimony.
silver silver.
gold gold.
platina platina.
Argill argill.

Note.—All these salts were unknown to the ancients; and even those
chemists who are most versant in modern discoveries, are yet at a lose
whether the greater part of the salts produced by the oxygenated acetic
radical belong properly to the class of acetites, or to that of acetats.—A.

Sect. XXXIV.—Observations upon Acetic Acid, and its
Combinations.

We have given to radical vinegar the name of acetic acid, from supposing
that it consists of the same radical with that of the acetous acid, but more
highly saturated with oxygen. According to this idea, acetic acid is the
highest degree of oxygenation of which the hydro-carbonous radical is
susceptible; but, although this circumstance be extremely probable, it
requires to be confirmed by farther, and more decisive experiments, before
it be adopted as an absolute chemical truth. We procure this acid as follows:
Upon three parts acetite of potash or of copper, pour one part of
concentrated sulphuric acid, and, by distillation, a very highly concentrated
vinegar is obtained, which we call acetic acid, formerly named radical
vinegar. It is not hitherto rigorously proved that this acid is more highly
oxygenated than the acetous acid, nor that the difference between them may
not consist in a different proportion between the elements of the radical or
base.

Table of the Combinations of Succinic Acid with the Salifiable
Bases, in the order of Affinity.

Bases. Neutral Salts.
Barytes Succinat of barytes.
Lime lime.

Potash potash.
Soda soda.
Ammoniac ammoniac.
Magnesia magnesia.
Argill argill.
Oxyd of zinc zinc.
iron iron.
manganese manganese.
cobalt cobalt.
nickel nickel.
lead lead.
tin tin.
copper copper.
bismuth bismuth.
antimony antimony.
arsenic arsenic.
mercury mercury.
silver silver.
gold gold.
platina platina.

Note.—All the succinats were unknown to the ancient chemists.—A.

Sect. XXXV.—Observations upon Succinic Acid, and its
Combinations.

The succinic acid is drawn from amber by sublimation in a gentle heat, and
rises in a concrete form into the neck of the subliming vessel. The operation
must not be pushed too far, or by too strong a fire, otherwise the oil of the
amber rises alongst with the acid. The salt is dried upon blotting paper, and
purified by repeated solution and crystallization.
This acid is soluble in twenty-four times its weight of cold water, and in a
much smaller quantity of hot water. It possesses the qualities of an acid in a
very small degree, and only affects the blue vegetable colours very slightly.

The affinities of this acid, with the salifiable bases, are taken from Mr de
Morveau, who is the first chemist that has endeavoured to ascertain them.

Sect. XXXVI.—Observations upon Benzoic Acid, and its
Combinations with Salifiable Bases[48].

This acid was known to the ancient chemists under the name of Flowers of
Benjamin, or of Benzoin, and was procured, by sublimation, from the gum
or resin called Benzoin: The means of procuring it, via humida, was
discovered by Mr Geoffroy, and perfected by Mr Scheele. Upon benzoin,
reduced to powder, pour strong lime-water, having rather an excess of lime;
keep the mixture continually stirring, and, after half an hour's digestion,
pour off the liquor, and use fresh portions of lime-water in the same manner,
so long as there is any appearance of neutralization. Join all the decanted
liquors, and evaporate, as far as possible, without occasioning
cristallization, and, when the liquor is cold, drop in muriatic acid till no
more precipitate is formed. By the former part of the process a benzoat of
lime is formed, and, by the latter, the muriatic acid combines with the lime,
forming muriat of lime, which remains dissolved, while the benzoic acid,
being insoluble, precipitates in a concrete state.

Sect. XXXVII.—Observations upon Camphoric Acid, and its
Combinations with Salifiable Bases[49].

Camphor is a concrete essential oil, obtained, by sublimation, from a
species of laurus which grows in China and Japan. By distilling nitric acid
eight times from camphor, Mr Kosegarten converted it into an acid
analogous to the oxalic; but, as it differs from that acid in some
circumstances, we have thought necessary to give it a particular name, till
its nature be more completely ascertained by farther experiment.
As camphor is a carbono-hydrous or hydro-carbonous radical, it is easily
conceived, that, by oxygenation, it should form oxalic, malic, and several
other vegetable acids: This conjecture is rendered not improbable by the
experiments of Mr Kosegarten; and the principal phenomena exhibited in
the combinations of camphoric acid with the salifiable bases, being very

similar to those of the oxalic and malic acids, lead me to believe that it
consists of a mixture of these two acids.

Sect. XXXVIII.—Observations upon Gallic Acid, and its
Combinations with Salifiable Bases[50].

The Gallic acid, formerly called Principle of Astringency, is obtained from
gall nuts, either by infusion or decoction with water, or by distillation with a
very gentle heat. This acid has only been attended to within these few years.
The Committee of the Dijon Academy have followed it through all its
combinations, and give the best account of it hitherto produced. Its acid
properties are very weak; it reddens the tincture of turnsol, decomposes
sulphurets, and unites to all the metals when they have been previously
dissolved in some other acid. Iron, by this combination, is precipitated of a
very deep blue or violet colour. The radical of this acid, if it deserves the
name of one, is hitherto entirely unknown; it is contained in oak willow,
marsh iris, the strawberry, nymphea, Peruvian bark, the flowers and bark of
pomgranate, and in many other woods and barks.

Sect. XXXIX.—Observations upon Lactic Acid, and its
Combinations with Salifiable Bases[51].

The only accurate knowledge we have of this acid is from the works of Mr
Scheele. It is contained in whey, united to a small quantity of earth, and is
obtained as follows: Reduce whey to one eighth part of its bulk by
evaporation, and filtrate, to separate all its cheesy matter; then add as much
lime as is necessary to combine with the acid; the lime is afterwards
disengaged by the addition of oxalic acid, which combines with it into an
insoluble neutral salt. When the oxalat of lime has been separated by
decantation, evaporate the remaining liquor to the consistence of honey; the
lactic acid is dissolved by alkohol, which does not unite with the sugar of
milk and other foreign matters; these are separated by filtration from the
alkohol and acid; and the alkohol being evaporated, or distilled off, leaves
the lactic acid behind.

This acid unites with all the salifiable bases forming salts which do not
cristallize; and it seems considerably to resemble the acetous acid.

Table of the Combinations of Saccholactic Acid with the
Salifiable Bases, in the Order of Affinity.

Bases. Neutral Salts.
Lime Saccholat of lime.
Barytes barytes.
Magnesia magnesia.
Potash potash.
Soda soda.
Ammoniac ammoniac.
Argill argill.
Oxyd of zinc zinc.
manganese manganese.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
arsenic arsenic.
bismuth bismuth.
mercury mercury.
antimony antimony.
silver silver.

Note.—All these were unknown to the ancient chemists.—A.

Sect. XL.—Observations upon Saccholactic Acid, and its
Combinations.

A species of sugar may be extracted, by evaporation, from whey, which has
long been known in pharmacy, and which has a considerable resemblance
to that procured from sugar canes. This saccharine matter, like ordinary
sugar, may be oxygenated by means of nitric acid: For this purpose, several
portions of nitric acid are distilled from it; the remaining liquid is
evaporated, and set to cristallize, by which means cristals of oxalic acid are
procured; at the same time a very fine white powder precipitates, which is
the saccholactic acid discovered by Scheele. It is susceptible of combining

with the alkalies, ammoniac, the earths, and even with the metals: Its action
upon the latter is hitherto but little known, except that, with them, it forms
difficultly soluble salts. The order of affinity in the table is taken from
Bergman.

Table of the Combinations of Formic Acid, with the Salifiable
Bases, in the Order of Affinity.

Bases. Neutral Salts.
Barytes Formiat of barytes.
Potash potash.
Soda soda.
Lime lime.
Magnesia magnesia.
Ammoniac ammoniac.
Oxyd of
zinc zinc.
manganese manganese.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
bismuth bismuth.
silver silver.
Argill argill.

Note.—All unknown to the ancient chemists.—A.

Sect. XLI.—Observations upon Formic Acid, and its
Combinations.

This acid was first obtained by distillation from ants, in the last century, by
Samuel Fisher. The subject was treated of by Margraff in 1749, and by

Messrs Ardwisson and Ochrn of Leipsic in 1777. The formic acid is drawn
from a large species of red ants, formica rufa, Lin. which form large ant
hills in woody places. It is procured, either by distilling the ants with a
gentle heat in a glass retort or an alembic; or, after having washed the ants
in cold water, and dried them upon a cloth, by pouring on boiling water,
which dissolves the acid; or the acid may be procured by gentle expression
from the insects, in which case it is stronger than in any of the former ways.
To obtain it pure, we must rectify, by means of distillation, which separates
it from the uncombined oily and charry matter; and it may be concentrated
by freezing, in the manner recommended for treating the acetous acid.

Sect. XLII.—Observations upon Bombic Acid, and its
Combinations with Acidifiable Bases[52].

The juices of the silk worm seem to assume an acid quality when that insect
changes from a larva to a chrysalis. At the moment of its escape from the
latter to the butterfly form, it emits a reddish liquor which reddens blue
paper, and which was first attentively observed by Mr Chaussier of the
Dijon academy, who obtains the acid by infusing silk worm chrysalids in
alkohol, which dissolves their acid without being charged with any of the
gummy parts of the insect; and, by evaporating the alkohol, the acid
remains tollerably pure. The properties and affinities of this acid are not
hitherto ascertained with any precision; and we have reason to believe that
analogous acids may be procured from other insects. The radical of this acid
is probably, like that of the other acids from the animal kingdom, composed
of charcoal, hydrogen, and azote, with the addition, perhaps, of phosphorus.

Table of the Combinations of Sebacic Acid, with the Salifiable
Bases, in the Order of Affinity.

Bases. Neutral Salts.
Barytes Sebat of barytes.
Potash potash.
Soda soda.
Lime lime.

Magnesia magnesia.
Ammoniac ammoniac.
Argill argill.
Oxyd of
zinc zinc.
manganese manganese.
iron iron.
lead lead.
tin tin.
cobalt cobalt.
copper copper.
nickel nickel.
arsenic arsenic.
bismuth bismuth.
mercury mercury.
antimony antimony.
silver silver.

Note.—All these were unknown to the ancient chemists.—A.

Sect. XLIII.—Observations upon Sebacid Acid, and its
Combinations.

To obtain the sebacic acid, let some suet be melted in a skillet over the fire,
alongst with some quick-lime in fine powder, and constantly stirred, raising
the fire towards the end of the operation, and taking care to avoid the
vapours, which are very offensive. By this process the sebacic acid unites
with the lime into a sebat of lime, which is difficultly soluble in water; it is,
however, separated from the fatty matters with which it is mixed by
solution in a large quantity of boiling water. From this the neutral salt is
separated by evaporation; and, to render it pure, is calcined, redissolved,
and again cristallized. After this we pour on a proper quantity of sulphuric
acid, and the sebacic acid passes over by distillation.

Sect. XLIV.—Observations upon the Lithic Acid, and its
Combinations with the Salifiable Bases[53].

From the later experiments of Bergman and Scheele, the urinary calculus
appears to be a species of salt with an earthy basis; it is slightly acidulous,
and requires a large quantity of water for solution, three grains being
scarcely soluble in a thousand grains of boiling water, and the greater part
again cristallizes when cold. To this concrete acid, which Mr de Morveau
calls Lithiasic Acid, we give the name of Lithic Acid, the nature and
properties of which are hitherto very little known. There is some appearance
that it is an acidulous neutral salt, or acid combined in excess with a
salifiable base; and I have reason to believe that it really is an acidulous
phosphat of lime; if so, it must be excluded from the class of peculiar acids.

Table of the Combinations of the Prussic Acid with the Salifiable
Bases, in the order of affinity.

Bases. Neutral Salts.
Potash Prussiat of potash.
Soda soda.
Ammoniac ammoniac.
Lime lime.
Barytes barytes.
Magnesia magnesia.
Oxyd of zinc zinc.
iron iron.
manganese manganese.
cobalt cobalt.
nickel nickel.
lead lead.
tin tin.
copper copper.
bismuth bismuth.
antimony antimony.

arsenic arsenic.
silver silver.
mercury mercury.
gold gold.
platina platina.

Note.—-All these were unknown to former chemists.—A.

Observations upon the Prussic Acid, and its Combinations.

As the experiments which have been made hitherto upon this acid seem still
to leave a considerable degree of uncertainty with regard to its nature, I
shall not enlarge upon its properties, and the means of procuring it pure and
dissengaged from combination. It combines with iron, to which it
communicates a blue colour, and is equally susceptible of entering into
combination with most of the other metals, which are precipitated from it
by the alkalies, ammoniac, and lime, in consequence of greater affinity. The
Prussic radical, from the experiments of Scheele, and especially from those
of Mr Berthollet, seems composed of charcoal and azote; hence it is an acid
with a double base. The phosphorus which has been found combined with it
appears, from the experiments of Mr Hassenfratz, to be only accidental.
Although this acid combines with alkalies, earths, and metals, in the same
way with other acids, it possesses only some of the properties we have been
in use to attribute to acids, and it may consequently be improperly ranked
here in the class of acids; but, as I have already observed, it is difficult to
form a decided opinion upon the nature of this substance until the subject
has been farther elucidated by a greater number of experiments.

FOOTNOTES:
[36] See Memoirs of the Academy for 1776, p. 671. and for 1778, p. 535,—A.
[37] See Part I. Chap. XI. upon this subject.—A.
[38] See Part I. Chap. XI. upon the application of these names according to the
proportions of the two ingredients.—A
[39] See Part I. Chap. XII. upon this subject.—A.

[40] Those who wish to see what has been said upon this great chemical
question by Messrs de Morveau, Berthollet, De Fourcroy, and myself, may
consult our translation of Mr Kirwan's Essay upon Phlogiston.—A.
[41] Saltpetre is likewise procured in large quantities by lixiviating the natural
soil in some parts of Bengal, and of the Russian Ukrain.—E.
[42] Commonly called Derbyshire spars.—E.
[43] I have not added the Table of these combinations, as the order of their
affinity is entirely unknown; they are called molybdats of argil, antimony,
potash, &c.—E.
[44] This acid was discovered by Mr Scheele, to whom chemistry is indebted for
the discovery of several other acids.—A.
[45] I have omitted the Table, as the order of affinity is unknown, and is given
by Mr Lavoisier only in alphabetical order. All the combinations of malic acid
with salifiable bases, which are named malats, were unknown to the ancient
chemists.—E.
[46] The order of affinity of the salifiable bases with this acid is hitherto
unknown. Mr Lavoisier, from its similarity to pyro-lignous acid, supposes the
order to be the same in both; but, as this is not ascertained by experiment, the
table is omitted. All these combinations, called Pyro-tartarites, were unknown
till lately—E.
[47] Savans Etrangers, Vol. III.
[48] These combinations are called Benzoats of Lime, Potash, Zinc, &c.; but, as
the order of affinity is unknown, the alphabetical table is omitted, as
unnecessary.—E.
[49] These combinations, which were all unknown to the ancients, are called
Camphorats. The table is omitted, as being only in alphabetical order.—E.
[50] These combinations, which are called Gallats, were all unknown to the
ancients; and the order of their affinity is not hitherto established.—A.
[51] These combinations are called Lactats; they were all unknown to the
ancient chemists, and their affinities have not yet been ascertained.—A.
[52] These combinations named Bombats were unknown to the ancient
chemists; and the affinities of the salifiable bases with the bombic acid are
hitherto undetermined.—A.
[53] All the combinations of this acid, should it finally turn out to be one, were
unknown to the ancient chemists, and its affinities with the salifiable bases have
not been hitherto determined.—A.

PART III.
Description of the Instruments and Operations of Chemistry.

INTRODUCTION.
In the two former parts of this work I designedly avoided being particular in
describing the manual operations of chemistry, because I had found from
experience, that, in a work appropriated to reasoning, minute descriptions of
processes and of plates interrupt the chain of ideas, and render the attention
necessary both difficult and tedious to the reader. On the other hand, if I had
confined myself to the summary descriptions hitherto given, beginners
could have only acquired very vague conceptions of practical chemistry
from my work, and must have wanted both confidence and interest in
operations they could neither repeat nor thoroughly comprehend. This want
could not have been supplied from books; for, besides that there are not any
which describe the modern instruments and experiments sufficiently at
large, any work that could have been consulted would have presented these
things under a very different order of arrangement, and in a different
chemical language, which must greatly tend to injure the main object of my
performance.
Influenced by these motives, I determined to reserve, for a third part of my
work, a summary description of all the instruments and manipulations
relative to elementary chemistry. I considered it as better placed at the end,
rather than at the beginning of the book, because I must have been obliged
to suppose the reader acquainted with circumstances which a beginner
cannot know, and must therefore have read the elementary part to become
acquainted with. The whole of this third part may therefore be considered as
resembling the explanations of plates which are usually placed at the end of
academic memoirs, that they may not interrupt the connection of the text by
lengthened description. Though I have taken great pains to render this part
clear and methodical, and have not omitted any essential instrument or
apparatus, I am far from pretending by it to set aside the necessity of
attendance upon lectures and laboratories, for such as wish to acquire
accurate knowledge of the science of chemistry. These should familiarise
themselves to the employment of apparatus, and to the performance of
experiments by actual experience. Nihil est in intellectu quod non prius
fuerit in sensu, the motto which the celebrated Rouelle caused to be painted

in large characters in a conspicuous part of his laboratory, is an important
truth never to be lost sight of either by teachers or students of chemistry.
Chemical operations may be naturally divided into several classes,
according to the purposes they are intended for performing. Some may be
considered as purely mechanical, such as the determination of the weight
and bulk of bodies, trituration, levigation, searching, washing, filtration,
&c. Others may be considered as real chemical operations, because they are
performed by means of chemical powers and agents; such are solution,
fusion, &c. Some of these are intended for separating the elements of
bodies from each other, some for reuniting these elements together; and
some, as combustion, produce both these effects during the same process.
Without rigorously endeavouring to follow the above method, I mean to
give a detail of the chemical operations in such order of arrangement as
seemed best calculated for conveying instruction. I shall be more particular
in describing the apparatus connected with modern chemistry, because these
are hitherto little known by men who have devoted much of their time to
chemistry, and even by many professors of the science.

CHAP. I.
Of the Instruments necessary for determining the Absolute and
Specific Gravities of Solid and Liquid Bodies.

The best method hitherto known for determining the quantities of
substances submitted to chemical experiment, or resulting from them, is by
means of an accurately constructed beam and scales, with properly
regulated weights, which well known operation is called weighing. The
denomination and quantity of the weights used as an unit or standard for
this purpose are extremely arbitrary, and vary not only in different
kingdoms, but even in different provinces of the same kingdom, and in
different cities of the same province. This variation is of infinite
consequence to be well understood in commerce and in the arts; but, in
chemistry, it is of no moment what particular denomination of weight be
employed, provided the results of experiments be expressed in convenient
fractions of the same denomination. For this purpose, until all the weights
used in society be reduced to the same standard, it will be sufficient for
chemists in different parts to use the common pound of their own country as
the unit or standard, and to express all its fractional parts in decimals,
instead of the arbitrary divisions now in use. By this means the chemists of
all countries will be thoroughly understood by each other, as, although the
absolute weights of the ingredients and products cannot be known, they will
readily, and without calculation, be able to determine the relative
proportions of these to each other with the utmost accuracy; so that in this
way we shall be possessed of an universal language for this part of
chemistry.
With this view I have long projected to have the pound divided into decimal
fractions, and I have of late succeeded through the assistance of Mr Fourche
balance-maker at Paris, who has executed it for me with great accuracy and
judgment. I recommend to all who carry on experiments to procure similar
divisions of the pound, which they will find both easy and simple in its
application, with a very small knowledge of decimal fractions[54].

As the usefulness and accuracy of chemistry depends entirely upon the
determination of the weights of the ingredients and products both before
and after experiments, too much precision cannot be employed in this part
of the subject; and, for this purpose, we must be provided with good
instruments. As we are often obliged, in chemical processes, to ascertain,
within a grain or less, the tare or weight of large and heavy instruments, we
must have beams made with peculiar niceness by accurate workmen, and
these must always be kept apart from the laboratory in some place where
the vapours of acids, or other corrosive liquors, cannot have access,
otherwise the steel will rust, and the accuracy of the balance be destroyed. I
have three sets, of different sizes, made by Mr Fontin with the utmost
nicety, and, excepting those made by Mr Ramsden of London, I do not
think any can compare with them for precision and sensibility. The largest
of these is about three feet long in the beam for large weights, up to fifteen
or twenty pounds; the second, for weights of eighteen or twenty ounces, is
exact to a tenth part of a grain; and the smallest, calculated only for
weighing about one gros, is sensibly affected by the five hundredth part of a
grain.
Besides these nicer balances, which are only used for experiments of
research, we must have others of less value for the ordinary purposes of the
laboratory. A large iron balance, capable of weighing forty or fifty pounds
within half a dram, one of a middle size, which may ascertain eight or ten
pounds, within ten or twelve grains, and a small one, by which about a
pound may be determined, within one grain.
We must likewise be provided with weights divided into their several
fractions, both vulgar and decimal, with the utmost nicety, and verified by
means of repeated and accurate trials in the nicest scales; and it requires
some experience, and to be accurately acquainted with the different
weights, to be able to use them properly. The best way of precisely
ascertaining the weight of any particular substance is to weigh it twice, once
with the decimal divisions of the pound, and another time with the common
subdivisions or vulgar fractions, and, by comparing these, we attain the
utmost accuracy.
By the specific gravity of any substance is understood the quotient of its
absolute weight divided by its magnitude, or, what is the same, the weight

of a determinate bulk of any body. The weight of a determinate magnitude
of water has been generally assumed as unity for this purpose; and we
express the specific gravity of gold, sulphuric acid, &c. by saying, that gold
is nineteen times, and sulphuric acid twice the weight of water, and so of
other bodies.
It is the more convenient to assume water as unity in specific gravities, that
those substances whose specific gravity we wish to determine, are most
commonly weighed in water for that purpose. Thus, if we wish to determine
the specific gravity of gold flattened under the hammer, and supposing the
piece of gold to weigh 8 oz. 4 gros 2-1/2 grs. in the air[55], it is suspended
by means of a fine metallic wire under the scale of a hydrostatic balance, so
as to be entirely immersed in water, and again weighed. The piece of gold
in Mr Brisson's experiment lost by this means 3 gros 37 grs.; and, as it is
evident that the weight lost by a body weighed in water is precisely equal to
the weight of the water displaced, or to that of an equal volume of water, we
may conclude, that, in equal magnitudes, gold weighs 4893-1/2 grs. and
water 253 grs. which, reduced to unity, gives 1.0000 as the specific gravity
of water, and 19.3617 for that of gold. We may operate in the same manner
with all solid substances. We have rarely any occasion, in chemistry, to
determine the specific gravity of solid bodies, unless when operating upon
alloys or metallic glasses; but we have very frequent necessity to ascertain
that of fluids, as it is often the only means of judging of their purity or
degree of concentration.
This object may be very fully accomplished with the hydrostatic balance,
by weighing a solid body; such, for example, as a little ball of rock cristal
suspended by a very fine gold wire, first in the air, and afterwards in the
fluid whose specific gravity we wish to discover. The weight lost by the
cristal, when weighed in the liquor, is equal to that of an equal bulk of the
liquid. By repeating this operation successively in water and different
fluids, we can very readily ascertain, by a simple and easy calculation, the
relative specific gravities of these fluids, either with respect to each other or
to water. This method is not, however, sufficiently exact, or, at least, is
rather troublesome, from its extreme delicacy, when used for liquids
differing but little in specific gravity from water; such, for instance, as
mineral waters, or any other water containing very small portions of salt in
solution.

In some operations of this nature, which have not hitherto been made
public, I employed an instrument of great sensibility for this purpose with
great advantage. It consists of a hollow cylinder, A b c f, Pl. vii. fig. 6. of
brass, or rather of silver, loaded at its bottom, b c f, with tin, as represented
swimming in a jug of water, l m n o. To the upper part of the cylinder is
attached a stalk of silver wire, not more than three fourths of a line
diameter, surmounted by a little cup d, intended for containing weights;
upon the stalk a mark is made at g, the use of which we shall presently
explain. This cylinder may be made of any size; but, to be accurate, ought at
least to displace four pounds of water. The weight of tin with which this
instrument is loaded ought to be such as will make it remain almost in
equilibrium in distilled water, and should not require more than half a dram,
or a dram at most, to make it sink to g.
We must first determine, with great precision, the exact weight of the
instrument, and the number of additional grains requisite for making it sink,
in distilled water of a determinate temperature, to the mark: We then
perform the same experiment upon all the fluids of which we wish to
ascertain the specific gravity, and, by means of calculation, reduce the
observed differences to a common standard of cubic feet, pints or pounds,
or of decimal fractions, comparing them with water. This method, joined to
experiments with certain reagents[56], is one of the best for determining the
quality of waters, and is even capable of pointing out differences which
escape the most accurate chemical analysis. I shall, at some future period,
give an account of a very extensive set of experiments which I have made
upon this subject.
These metallic hydrometers are only to be used for determining the specific
gravities of such waters as contain only neutral salts or alkaline substances;
and they may be constructed with different degrees of ballast for alkohol
and other spiritous liquors. When the specific gravities of acid liquors are to
be ascertained, we must use a glass hydrometer, as represented Pl. vii. fig.
14[57]. This consists of a hollow cylinder of glass, a b c f, hermetically
sealed at its lower end, and drawn out at the upper into a capillary tube a,
ending in the little cup or bason d. This instrument is ballasted with more or
less mercury, at the bottom of the cylinder introduced through the tube, in
proportion to the weight of the liquor intended to be examined: We may
introduce a small graduated slip of paper into the tube a d; and, though

these degrees do not exactly correspond to the fractions of grains in the
different liquors, they may be rendered very useful in calculation.
What is said in this chapter may suffice, without farther enlargement, for
indicating the means of ascertaining the absolute and specific gravities of
solids and fluids, as the necessary instruments are generally known, and
may easily be procured: But, as the instruments I have used for measuring
the gasses are not any where described, I shall give a more detailed account
of these in the following chapter.

FOOTNOTES:
[54] Mr Lavoisier gives, in this part of his work, very accurate directions for
reducing the common subdivisions of the French pound into decimal fractions,
and vice versa, by means of tables subjoined to this 3d part. As these
instructions, and the table, would be useless to the British chemist, from the
difference between the subdivisions of the French and Troy pounds, I have
omitted them, but have subjoined in the appendix accurate rules for converting
the one into the other.—E.
[55] Vide Mr Brisson's Essay upon Specific Gravity, p. 5.—A.
[56] For the use of these reagents see Bergman's excellent treatise upon the
analysis of mineral waters, in his Chemical and Physical Essays.—E.
[57] Three or four years ago, I have seen similar glass hydrometers, made for Dr
Black by B. Knie, a very ingenious artist of this city.—E.

CHAP. II.
Of Gazometry, or the Measurement of the Weight and Volume of
Aëriform Substances.

SECT. I.

Description of the Pneumato-chemical Apparatus.

The French chemists have of late applied the name of pneumato-chemical
apparatus to the very simple and ingenious contrivance, invented by Dr
Priestley, which is now indispensibly necessary to every laboratory. This
consists of a wooden trough, of larger or smaller dimensions as is thought
convenient, lined with plate-lead or tinned copper, as represented in
perspective, Pl. V. In Fig. 1. the same trough or cistern is supposed to have
two of its sides cut away, to show its interior construction more distinctly.
In this apparatus, we distinguish between the shelf ABCD Fig. 1. and 2. and
the bottom or body of the cistern FGHI Fig. 2. The jars or bell-glasses are
filled with water in this deep part, and, being turned with their mouths
downwards, are afterwards set upon the shelf ABCD, as shown Plate X.
Fig. 1. F. The upper parts of the sides of the cistern above the level of the
shelf are called the rim or borders.
The cistern ought to be filled with water, so as to stand at least an inch and a
half deep upon the shelf, and it should be of such dimensions as to admit of
at least one foot of water in every direction in the well. This size is
sufficient for ordinary occasions; but it is often convenient, and even
necessary, to have more room; I would therefore advise such as intend to
employ themselves usefully in chemical experiments, to have this apparatus
made of considerable magnitude, where their place of operating will allow.
The well of my principal cistern holds four cubical feet of water, and its
shelf has a surface of fourteen square feet; yet, in spite of this size, which I
at first thought immoderate, I am often straitened for room.

In laboratories, where a considerable number of experiments are performed,
it is necessary to have several lesser cisterns, besides the large one, which
may be called the general magazine; and even some portable ones, which
may be moved when necessary, near a furnace, or wherever they may be
wanted. There are likewise some operations which dirty the water of the
apparatus, and therefore require to be carried on in cisterns by themselves.
It were doubtless considerably cheaper to use cisterns, or iron-bound tubs,
of wood simply dove-tailed, instead of being lined with lead or copper; and
in my first experiments I used them made in that way; but I soon discovered
their inconvenience. If the water be not always kept at the same level, such
of the dovetails as are left dry shrink, and, when more water is added, it
escapes through the joints, and runs out.
We employ cristal jars or bell glasses, Pl. V. Fig. 9. A. for containing the
gasses in this apparatus; and, for transporting these, when full of gas, from
one cistern to another, or for keeping them in reserve when the cistern is too
full, we make use of a flat dish BC, surrounded by a standing up rim or
border, with two handles DE for carrying it by.
After several trials of different materials, I have found marble the best
substance for constructing the mercurial pneumato-chemical apparatus, as it
is perfectly impenetrable by mercury, and is not liable, like wood, to
separate at the junctures, or to allow the mercury to escape through chinks;
neither does it run the risk of breaking, like glass, stone-ware, or porcelain.
Take a block of marble BCDE, Plate V. Fig. 3. and 4. about two feet long,
15 or 18 inches broad, and ten inches thick, and cause it to be hollowed out
as at m n Fig. 5. about four inches deep, as a reservoir for the mercury; and,
to be able more conveniently to fill the jars, cut the gutter T V, Fig. 3. 4. and
5. at least four inches deeper; and, as this trench may sometimes prove
troublesome, it is made capable of being covered at pleasure by thin boards,
which slip into the grooves x y, Fig. 5. I have two marble cisterns upon this
construction, of different sizes, by which I can always employ one of them
as a reservoir of mercury, which it preserves with more safety than any
other vessel, being neither subject to overturn, nor to any other accident. We
operate with mercury in this apparatus exactly as with water in the one
before described; but the bell-glasses must be of smaller diameter, and
much stronger; or we may use glass tubes, having their mouths widened, as

in Fig. 7.; these are called eudiometers by the glass-men who sell them. One
of the bell-glasses is represented Fig. 5. A. standing in its place, and what is
called a jar is engraved Fig. 6.
The mercurial pneumato-chemical apparatus is necessary in all experiments
wherein the disengaged gasses are capable of being absorbed by water, as is
frequently the case, especially in all combinations, excepting those of
metals, in fermentation, &c.

SECT. II.

Of the Gazometer.

I give the name of gazometer to an instrument which I invented, and caused
construct, for the purpose of a kind of bellows, which might furnish an
uniform and continued stream of oxygen gas in experiments of fusion. Mr
Meusnier and I have since made very considerable corrections and
additions, having converted it into what may be called an universal
instrument, without which it is hardly possible to perform most of the very
exact experiments. The name we have given the instrument indicates its
intention for measuring the volume or quantity of gas submitted to it for
examination.
It consists of a strong iron beam, DE, Pl. VIII. Fig. 1. three feet long, having
at each end, D and E, a segment of a circle, likewise strongly constructed of
iron, and very firmly joined. Instead of being poised as in ordinary
balances, this beam rests, by means of a cylindrical axis of polished steel, F,
Fig. 9. upon two large moveable brass friction-wheels, by which the
resistance to its motion from friction is considerably diminished, being
converted into friction of the second order. As an additional precaution, the
parts of these wheels which support the axis of the beam are covered with
plates of polished rock-cristal. The whole of this machinery is fixed to the
top of the solid column of wood BC, Fig. 1. To one extremity D of the
beam, a scale P for holding weights is suspended by a flat chain, which
applies to the curvature of the arc nDo, in a groove made for the purpose.
To the other extremity E of the beam is applied another flat chain, i k m, so
constructed, as to be incapable of lengthening or shortening, by being less

or more charged with weight; to this chain, an iron trivet, with three
branches, a i, c i, and h i, is strongly fixed at i, and these branches support a
large inverted jar A, of hammered copper, of about 18 inches diameter, and
20 inches deep. The whole of this machine is represented in perspective, Pl.
VIII. Fig. 1. and Pl. IX. Fig. 2. and 4. give perpendicular sections, which
show its interior structure.
Round the bottom of the jar, on its outside, is fixed (Pl. IX. Fig. 2.) a border
divided into compartments 1, 2, 3, 4, &c. intended to receive leaden weights
separately represented 1, 2, 3, Fig. 3. These are intended for increasing the
weight of the jar when a considerable pressure is requisite, as will be
afterwards explained, though such necessity seldom occurs. The cylindrical
jar A is entirely open below, de, Pl. IX. Fig. 4.; but is closed above with a
copper lid, a b c, open at b f, and capable of being shut by the cock g. This
lid, as may be seen by inspecting the figures, is placed a few inches within
the top of the jar to prevent the jar from being ever entirely immersed in the
water, and covered over. Were I to have this instrument made over again, I
should cause the lid to be considerably more flattened, so as to be almost
level. This jar or reservoir of air is contained in the cylindrical copper
vessel, LMNO, Pl. VIII. Fig. 1. filled with water.
In the middle of the cylindrical vessel LMNO, Pl. IX. Fig. 4. are placed two
tubes st, xy, which are made to approach each other at their upper
extremities t y; these are made of such a length as to rise a little above the
upper edge LM of the vessel LMNO, and when the jar abcde touches the
bottom NO, their upper ends enter about half an inch into the conical
hollow b, leading to the stop-cock g.
The bottom of the vessel LMNO is represented Pl. IX. Fig. 3. in the middle
of which a small hollow semispherical cap is soldered, which may be
considered as the broad end of a funnel reversed; the two tubes st, xy, Fig.
4. are adapted to this cap at s and x, and by this means communicate with
the tubes mm, nn, oo, pp, Fig. 3. which are fixed horizontally upon the
bottom of the vessel, and all of which terminate in, and are united by, the
spherical cap sx. Three of these tubes are continued out of the vessel, as in
Pl. VIII. Fig. 1. The first marked in that figure 1, 2, 3, is inserted at its
extremity 3, by means of an intermediate stop-cock 4, to the jar V. which
stands upon the shelf of a small pneumato-chemical apparatus GHIK, the

inside of which is shown Pl. IX. Fig. 1. The second tube is applied against
the outside of the vessel LMNO from 6 to 7, is continued at 8, 9, 10, and at
11 is engaged below the jar V. The former of these tubes is intended for
conveying gas into the machine, and the latter for conducting small
quantities for trials under jars. The gas is made either to flow into or out of
the machine, according to the degree of pressure it receives; and this
pressure is varied at pleasure, by loading the scale P less or more, by means
of weights. When gas is to be introduced into the machine, the pressure is
taken off, or even rendered negative; but, when gas is to be expelled, a
pressure is made with such degree of force as is found necessary.
The third tube 12, 13, 14, 15, is intended for conveying air or gas to any
necessary place or apparatus for combustions, combinations, or any other
experiment in which it is required.
To explain the use of the fourth tube, I must enter into some discussions.
Suppose the vessel LMNO, Pl. VIII. Fig. 1. full of water, and the jar A
partly filled with gas, and partly with water; it is evident that the weights in
the bason P may be so adjusted, as to occasion an exact equilibrium
between the weight of the bason and of the jar, so that the external air shall
not tend to enter into the jar, nor the gas to escape from it; and in this case
the water will stand exactly at the same level both within and without the
jar. On the contrary, if the weight in the bason P be diminished, the jar will
then press downwards from its own gravity, and the water will stand lower
within the jar than it does without; in this case, the included air or gas will
suffer a degree of compression above that experienced by the external air,
exactly proportioned to the weight of a column of water, equal to the
difference of the external and internal surfaces of the water. From these
reflections, Mr Meusnier contrived a method of determining the exact
degree of pressure to which the gas contained in the jar is at any time
exposed. For this purpose, he employs a double glass syphon 19, 20, 21, 22,
23, firmly cemented at 19 and 23. The extremity 19 of this syphon
communicates freely with the water in the external vessel of the machine,
and the extremity 23 communicates with the fourth tube at the bottom of the
cylindrical vessel, and consequently, by means of the perpendicular tube st,
Pl. IX. Fig. 4. with the air contained in the jar. He likewise cements, at 16,
Pl. VIII. Fig. 1. another glass tube 16, 17, 18, which communicates at 16