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 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 } ------------+----------------+--------------------+--------------------+
------------+----------------+-----------------------------------------+ |Names of |Third degree of oxygenation. | |the simple +--------------------+--------------------+ |substances. |New Names. |Ancient Names. | +----------------+--------------------+--------------------+ {Caloric | | | { | | | {Hydrogen. | | | { | | | {Azote {Nitric acid {Pale, or not } { { {smoaking nitrous } { | {acid | { | | | Combinations{Charcoal {Carbonic acid |Fixed air | of oxygen { | | | with {Sulphur |Sulphuric acid |Vitriolic acid | simple { | | | non-metallic{Phosphorus |Phosphoric acid |Phosphoric acid | substances. { | | | {Muriatic radical}Muriatic acid |Marine acid | { | | | {Fluoric radical }Fluoric acid |Unknown till lately | { | | | {Boracic radical }Boracic acid {Homberg's sedative | { } {salt | ------------------------------------------------------------------------ {Antimony |Antimonic acid | | { | | | {Silver |Argentic acid | | { | | | {Arsenic |Arseniac acid |Acid of arsenic | { | | | {Bismuth |Bismuthic acid | | { | | | {Cobalt |Cobaltic acid | | { | | | {Copper |Cupric acid | | { | | | {Tin |Stannic acid | | { | | | {Iron |Ferric acid | | Combinations{ | | | of oxygen {Manganese |Manganesic acid | | with the { | | | simple { | | | metallic {Mercury |Mercuric acid | | substances. { | | | {Molybdena |Molybdic acid |Acid of molybdena { { | | | {Nickel |Nickelic acid | | { | | | {Gold |Auric acid | | { | | | {Platina |Platinic acid | | { | | | {Lead |Plumbic acid | | { | | | {Tungstein |Tungstic acid |Acid of Tungstein { { | | | {Zinc |Zincic acid | | ------------+----------------+--------------------+--------------------+
------------+----------------+------------------------------------------+ |Names of |Fourth degree of oxygenation. | |the simple +---------------------+--------------------+ |substances. |New Names. |Ancient Names. | +----------------+---------------------+--------------------+ {Caloric | | | { | | | {Hydrogen. | | | { | | | {Azote {Oxygenated nitric |Unknown | { {acid | | { | | | {Charcoal {Oxygenated carbonic |Unknown | Combinations{ {acid | | of oxygen { | | | with {Sulphur |Oxygenated sulphuric |Unknown | simple { |acid | | non-metallic{Phosphorus |Oxygenated phosphoric|Unknown | substances. { |acid | | { | | | {Muriatic radical}Oxygenated muriatic {Dephlogisticated | { |acid |marine acid | { | | | {Fluoric radical } | | { | | | {Boracic radical } | | { } | | ------------------------------------------------------------------------ {Antimony | | | { | | | {Silver | | | { | | | {Arsenic |Oxygenated arseniac |Unknown | { |acid | | { | | | {Bismuth | | | { | | | {Cobalt | | | { | | | {Copper | | | { | | | {Tin | | | { | | | {Iron | | | { | | | Combinations{ | | | of oxygen {Manganese | | | with the { | | | simple { | | | metallic {Mercury | | | substances. { | | | {Molybdena |Oxygenated molybdic |Unknown | { |acid | | {Nickel | | | { | | | {Gold | | | { | | | {Platina | | | { | | | {Lead | | | { | | | {Tungstein |Oxygenated Tungstic }Unknown | { |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 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.
[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 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.
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_ _Resulting Compounds._ _Substances._ _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, {hydruret of iron, &c. } as 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.
Hydrogen Sulphuret of 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 Potash potash { with fixed vegetable alkali.
{ Alkaline liver of sulphur Soda soda { with fixed mineral { alkali.
{ Volatile liver of sulphur, Ammoniac ammoniac { smoaking 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, Lime } Soda, &c.(B) 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_ _Substances._ _Resulting Compounds._
{ Oxyd of charcoal Unknown. Oxygen { Carbonic acid Fixed air, chalky acid.
Sulphur Carburet of sulphur } Phosphorus Carburet of phosphorus } Unknown. Azote Carburet of azote }
{ Carbono-hydrous radical Hydrogen { Fixed and volatile oils
{ Of these only the carburets of Metallic substances Carburets of metals { iron and zinc are known, and { were formerly called Plumbago.
Alkalies and earths Carburet of potash, &c. Unknown.
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 bases._ _Names of the neutral salts._ _New nomenclature._ _Notes._
Barytes Nitrite of barytes. { Potash potash. { These salts are only Soda soda. { known of late, and Lime lime. { have received no particular Magnesia magnesia. { name in the old Ammoniac ammoniac. { nomenclature. Argill argill. {
{ As metals dissolve both in nitrous and Oxyd of zinc zinc. { nitric acids, metallic salts must of iron iron. { consequence be formed having manganese manganese. { different degrees of oxygenation. cobalt cobalt. { Those wherein the metal is nickel nickel. { least oxygenated must be lead lead. { called Nitrites, when more so, tin tin. { Nitrats; but the limits of this copper copper. { distinction are difficultly bismuth bismuth. { ascertainable. The older antimony antimony. { chemists were not acquainted arsenic arsenic. { with any of these salts. mercury mercury. {
silver { It is extremely probable that gold, silver gold { and platina only form nitrats, 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 nomenclature._ _Old nomenclature._
Barytes Nitrat of barytes Nitre, with a base of heavy earth. Potash potash Nitre, saltpetre. Nitre with base of potash.
Soda soda { Quadrangular nitre. Nitre with base of { mineral alkali.
{ Calcareous nitre. Nitre with Lime lime { calcareous base. Mother water { of nitre, or saltpetre.
Magnesia magnesia Magnesian nitre. Nitre with base of magnesia. Ammoniac ammoniac Ammoniacal nitre.
{ Nitrous alum. Argillaceous nitre. Nitre Argill argill { with base of earth of alum.
Oxyd of zinc zinc Nitre of zinc. iron iron Nitre of iron. Martial nitre. 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. silver silver Nitre of silver or luna. Lunar 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._
Barytes Sulphat of barytes Heavy spar. Vitriol of heavy earth.
Potash potash {Vitriolated tartar. Sal { de duobus. Arcanum { duplicatam.
Soda soda Glauber's salt. Lime lime Selenite, gypsum, calcareous vitriol. Magnesia magnesia Epsom salt, sedlitz salt, magnesian vitriol. Ammoniac ammoniac Glauber's secret sal ammoniac. Argill argill Alum.
Oxyd of zinc zinc {White vitriol, goslar { vitriol, white coperas, { vitriol of zinc.
iron iron {Green coperas, green { vitriol, 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.
copper copper {Blue coperas, blue vitriol, { 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_ _Names of the Neutral Salts formed by_ _Bases._ _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,