Part 3 (2/2)

FOOTNOTES:

[11] It h here oeneral principles of the new noues called the carbonic acid, and when in the aeriforas E

CHAP VI

_Of the Noeneral, and particularly of those drawn from Nitre and Sea-Salt_

It becomes extre chapter, to establish a syste used as a generic tere, as in nature, by the naeneric naenation of phosphorus, of sulphur, and of charcoal; and these products are respectively named, the _phosphoric acid_, the _sulphuric acid_, and the _carbonic acid_

There is however, a reenation of combustible bodies, and of a part of such bodies as are convertible into acids, that they are susceptible of different degrees of saturation with oxygen, and that the resulting acids, though formed by the union of the sa upon that difference of proportion Of this, the phosphoric acid, and more especially the sulphuric, furnishes us with examples When sulphur is coen, it forenation, a volatile acid, having a penetrating odour, and possessed of very particular qualities By a larger proportion of oxygen, it is changed into a fixed, heavy acid, without any odour, and which, by coives products quite different from those furnished by the former In this instance, the principles of our nomenclature seem to fail; and it seems difficult to derive such terms from the name of the acidifiable base, as shall distinctly express these two degrees of saturation, or oxygenation, without circumlocution By reflection, however, upon the subject, or perhaps rather froht it allowable to express these varieties in the oxygenation of the acids, by si the termination of their specific names The volatile acid produced from sulphur was anciently known to Stahl under the name of _sulphurous_ acid[12] We have preserved that teren; and distinguish the other, or coenated acid, by the name of _sulphuric_ acid We shall therefore say, in this new cheen, is susceptible of two degrees of saturation; that the first, or lesser degree, constitutes sulphurous acid, which is volatile and penetrating; whilst the second, or higher degree of saturation, produces sulphuric acid, which is fixed and inodorous We shall adopt this difference of terrees of saturation Hence we have a phosphorous and a phosphoric acid, an acetous and an acetic acid; and so on, for others in similar circumstances

This part of chemical science would have been extremely simple, and the nomenclature of the acids would not have been at all perplexed, as it is now in the old nomenclature, if the base or radical of each acid had been knohen the acid itself was discovered Thus, for instance, phosphorus being a known substance before the discovery of its acid, this latter was rightly distinguished by a term drawn from the name of its acidifiable base But when, on the contrary, an acid happened to be discovered before its base, or rather, when the acidifiable base from which it was formed remained unknown, names were adopted for the thich have not the smallest connection; and thus, not only the memory became burthened with useless appellations, but even the minds of students, nay even of experienced chemists, became filled with false ideas, which tiive an instance of this confusion with respect to the acid sulphur: The for procured this acid froave it the name of the vitriolic acid from the nanorant that the acid procured from sulphur by co happened with the aerifor known that this acid was the result of coen, a variety of denoiven to it, not one of which conveys just ideas of its nature or origin We have found it extree with respect to these acids proceeding fro converted the name of _vitriolic acid_ into that of _sulphuric_, and the name of _fixed air_ into that of _carbonic acid_; but it is impossible to follow this plan with the acids whose bases are still unknoith these we have been obliged to use a contrary plan, and, instead of for the name of the acid from that of its base, have been forced to denominate the unknown base from the name of the known acid, as happens in the case of the acid which is procured froe this acid from the alkaline base hich it is combined, we have only to pour sulphuric acid upon sea-salt, immediately a brisk effervescence takes place, white vapours arise, of a very penetrating odour, and, by only gently heating the mixture, all the acid is driven off As, in the common temperature and pressure of our atas, weit in proper vessels For small experiments, the most simple and most co 5), into which the sea-salt is introduced, well dried[13], we then pour on some concentrated sulphuric acid, and immediately introduce the beak of the retort under little jars or bell-glasses A, (sa), previously filled with quicksilver In proportion as the acid gas is disengaged, it passes into the jar, and gets to the top of the quicksilver, which it displaces

When the disengageentle heat is applied to the retort, and gradually increased till nothingaffinity ater, which absorbs an enor a very thin layer of water into the glass which contains the gas; for, in an instant, the whole acid gas disappears, and combines with the water

This latter circue of in laboratories and manufactures, on purpose to obtain the acid of sea-salt in a liquid for 1) is employed

It consists, 1st, of a tubulated retort A, into which the sea-salt, and after it the sulphuric acid, are introduced through the opening H; 2d, of the baloon or recipient c, b, intended for containing the s the process; and, 3d, of a set of bottles, with two mouths, L, L, L, L, half filled ater, intended for absorbing the gas disengaged by the distillation This apparatus will be more ah we have not yet been able, either to compose or to decompound this acid of sea-salt, we cannot have the smallest doubt that it, like all other acids, is coen with an acidifiable base We have therefore called this unknown substance the _ this naman and Mr de Morveau, fronify sea-salt Thus, without being able exactly to detern, by that teras in the common temperature and pressure of our atreat quantity, ater, and whose acidifiable base adheres so very intien, that nothem If ever this acidifiable base of the h now unknown in that capacity, it will be requisite to change its present denoous with that of its base

In common with sulphuric acid, and several other acids, the enation; but the excess of oxygen produces quite contrary effects upon it from what the same circuree of oxygenation converts sulphur into a volatile gasseous acid, which only enation forer acid properties, which is very fixed and cannot reh tee proportion ater With muriatic acid, the direct reverse takes place; an additional saturation with oxygen renders itodour, less miscible ater, and diminishes its acid properties We were at first inclined to have denorees of saturation in the sa the less oxygenated _en _ives very particular results in its coous to it is yet known in chemistry, we have left the naive the latter the enated h the base or radical of the acid which is extracted froed proper only to modify its name in the same manner with that of the muriatic acid It is drawn from nitre, by the intervention of sulphuric acid, by a process si the1) In proportion as the acid passes over, it is in part condensed in the baloon or recipient, and the rest is absorbed by the water contained in the bottles L,L,L,L; the water becoreen, then blue, and at last yellow, in proportion to the concentration of the acid During this operation, a large quantity of oxygen gas, ed

This acid, like all others, is coen, united to an acidifiable base, and is even the first acid in which the existence of oxygen ell ascertained Its two constituent elements are but weakly united, and are easily separated, by presenting any substance hich oxygen has a stronger affinity than with the acidifiable base peculiar to this acid By some experiments of this kind, it was first discovered that azote, or the base of as, constituted its acidifiable base or radical; and consequently that the acid of nitre was really an azotic acid, having azote for its base, coht be consistent with our principles, it appeared necessary, either to call the acid by the name of _azotic_, or to name the base _nitric radical_; but fro considerations In the _first_ place, it seee the name of nitre or saltpetre, which has been universally adopted in society, in manufactures, and in che been discovered by Mr Berthollet to be the base of volatile alkali, or aht it improper to call it nitric radical We have therefore continued the term of azote to the base of that part of atmospheric air which is likewise the nitric and ammoniacal radical; and we have naenation, _nitrous acid_ in the for its former appellation properly modified

Several very respectable chemists have disapproved of this deference for the old ter a new chee; so that, by thus steering a kind of middle course, we have exposed ourselves to the censures of one sect of chemists, and to the expostulations of the opposite party

The acid of nitre is susceptible of assuree of oxygenation, or upon the proportions in which azote and oxygen enter into its coenation, it foras, which we shall continue to naas_; this is coen combined with one part of azote; and in this state it is not as, the azote is by no en, but, on the contrary, has still a very great affinity for that element, and even attracts it fro into contact with it This coas with atmospheric air has even becoen contained in air, and consequently for ascertaining its degree of salubrity

This addition of oxygen converts the nitrous gas into a powerful acid, which has a strong affinity ater, and which is itself susceptible of various additional degrees of oxygenation When the proportions of oxygen and azote is below three parts, by weight, of the former, to one of the latter, the acid is red coloured, and eentle heat, it gives out nitrous gas; and we terenation, _nitrous acid_ When four parts, by weight, of oxygen, are combined with one part of azote, the acid is clear and colourless, more fixed in the fire than the nitrous acid, has less odour, and its constituent elements are more firmly united This species of acid, in conformity with our principles of nomenclature, is called _nitric acid_

Thus, nitric acid is the acid of nitre, surcharged with oxygen; nitrous acid is the acid of nitre surcharged with azote; or, what is the saas; and this latter is azote not sufficiently saturated with oxygen to possess the properties of an acid To this degree of oxygenation, we have afterwards, in the course of this work, given the generical name of _oxyd_[14]