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.
}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.
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. 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, &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.
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:
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.
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.
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.
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; 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.
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, 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 is presented in four sections to comply with 75 character line limitation.]
TABLE of the binary Combinations of Oxygen with simple Substances
------------+----------------+-----------------------------------------+ |Names of |First degree of oxygenation. | |the simple +--------------------+--------------------+ |substances. |New Names. |Ancient Names. | +----------------+--------------------+--------------------+ {Caloric |Oxygen gas {Vital or | { | {dephlogisticated | { | {air | { | { | {Hydrogen. |Water(A). | | { | | | {Azote {Nitrous oxyd, or }Nitrous gas or air | { {base of nitrous gas } | { | | | {Charcoal {Oxyd of charcoal, or}Unknown | Combinations{ {carbonic oxyd } | of oxygen { | | | with {Sulphur |Oxyd of sulphur |Soft sulphur | simple { | | | non-metallic{Phosphorus |Oxyd of phosphorus {Residuum from the } substances. { | {combustion of } { | {phosphorus } { | | | {Muriatic radical}Muriatic oxyd |Unknown | { | | | {Fluoric radical }Fluoric oxyd |Unknown | { | | | {Boracic radical }Boracic oxyd |Unknown | ------------------------------------------------------------------------ {Antimony |Grey oxyd of |Grey calx of | { |antimony |antimony | { | | | {Silver |Oxyd of silver |Calx of silver | { | | | {Arsenic |Grey oxyd of arsenic|Grey calx of arsenic| { | | | {Bismuth |Grey oxyd of bismuth|Grey calx of bismuth| { | | | { | | | {Cobalt |Grey oxyd of cobalt |Grey calx of cobalt | { | | | {Copper |Brown oxyd of copper|Brown calx of copper{ { | | { {Tin |Grey oxyd of tin |Grey calx of tin | { | | | {Iron |Black oxyd of iron |Martial ethiops { Combinations{ | | | of oxygen {Manganese |Black oxyd of |Black calx of | with the { |manganese |manganese | simple { | | | metallic {Mercury |Black oxyd of |Ethiops mineral(B) { substances. { |mercury | { { | | | {Molybdena |Oxyd of molybdena |Calx of molybdena | { | | | {Nickel |Oxyd of nickel |Calx of nickel | { | | | {Gold |Yellow oxyd of gold |Yellow calx of gold | { | | | {Platina |Yellow oxyd of |Yellow calx of | { |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 |Second degree of oxygenation. | |the simple +--------------------+--------------------+ |substances. |New Names. |Ancient Names. | +----------------+--------------------+--------------------+ {Caloric | | | { | | | {Hydrogen. | | | { | | | {Azote {Nitrous acid |Smoaking nitrous | { { |acid | { | | | {Charcoal {Carbonous acid |Unknown | Combinations{ { | | of oxygen {Sulphur |Sulphurous acid |Sulphureous acid | with simple { | | | non-metallic{Phosphorus |Phosphorous acid {Volatile acid of } substances. { | {phosphorus } { | | | {Muriatic radical}Muriatous acid |Unknown | { | | | {Fluoric radical }Fluorous acid |Unknown | { | | | {Boracic radical }Boracous acid |Unknown | ------------------------------------------------------------------------ {Antimony |White oxyd of {White calx of } { |antimony {antimony } { | {diaphoretic antimony} { | | | {Silver | | | { | | | {Arsenic |White oxyd of |White calx of | { |arsenic |arsenic | { | | | {Bismuth |White oxyd of |White calx of | { |bismuth |bismuth | { | | | {Cobalt | | | { | | | {Copper |Blue and green oxyds}Blue and green | { |of copper }calces of copper | { | | | {Tin |White oxyd of tin {White calx of tin, } { | {or putty of tin } { | | | {Iron |Yellow and red oxyds}Ochre and rust of | { |of iron }iron | Combinations{ | | | of oxygen {Manganese |White oxyd of |White calx of | with the { |manganese |manganese | simple { | | | metallic {Mercury |Yellow and red oxyds{Turbith mineral, } substances. { |of mercury {red precipitate, } { | {calcinated mercury, } { | {precipitate per se } { | | | {Molybdena | | | { | | | {Nickel | | | { | | | {Gold |Red oxyd of gold {Red calx of gold, } { | {purple precipitate } { | |of cassius | { | | | {Platina | | | { | | | {Lead |Yellow and red oxyds}Massicot and minium | { |of lead } | { | | | {Tungstein | | | { | | | {Zinc |White oxyd of zinc {White calx of zinc, } { | {pompholix } ------------+----------------+--------------------+--------------------+
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 radicals. Names of the resulting acids.
New nomenclature. Old nomenclature.
Nitro muriatic} Nitro muriatic acid Aqua regia. radical }
(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 acid Empyr. acid of tartar. 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. Gallic Gallic acid {The astringent principle {of 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.
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.
TABLE of the Binary Combinations of Azote with the Simple Substances.
Simple Substances. Results of the Combinations. New Nomenclature. Old Nomenclature.
Caloric Azotic gas Phlogisticated air, or 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
Charcoal {the principles of our nomenclature, Azuret of
{Charcoal. Charcoal dissolves in azotic gas, and
{forms carbonated azotic gas.
Phosphorus. Azuret of phosphorus. Still unknown.
{Azuret of sulphur. Still unknown. We know
Sulphur {that sulphur dissolves in azotic gas, forming
{sulphurated azotic gas.
{Azote combines with charcoal and hydrogen, and Compound {sometimes with phosphorus, in the compound radicals {oxydable and acidifiable bases, and is generally {contained in the radicals of the animal acids.
{Such combinations are hitherto unknown; if ever Metallic {discovered, they will form metallic azurets, as substances {azuret of gold, of silver, &c.
Lime { Magnesia { Barytes {Entirely unknown. If ever discovered, they will Argill {form azuret of lime, azuret of 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.
