Elements of Chemistry Part 17

tin tin Aerated tin.

copper copper Aerated copper.

bis.m.u.th bis.m.u.th Aerated bis.m.u.th.

antimony antimony Aerated antimony.

a.r.s.enic a.r.s.enic Aerated a.r.s.enic.

mercury mercury Aerated mercury.

silver silver Aerated silver.

gold gold Aerated gold.

platina platina Aerated platina.

[Note A: As these salts have only been understood of late, they have not, properly speaking, any old names. Mr Morveau, in the First Volume of the Encyclopedia, calls them _Mephites_; Mr Bergman gives them the name of _aerated_; and Mr de Fourcroy, who calls the carbonic acid _chalky acid_, gives them the name of _chalks_.--A]

SECT. XVII.--_Observations upon Carbonic Acid, and its Combinations._

Of all the known acids, the carbonic is the most abundant in nature; it exists ready formed in chalk, marble, and all the calcareous stones, in which it is neutralized by a particular earth called _lime_. To disengage it from this combination, nothing more is requisite than to add some sulphuric acid, or any other which has a stronger affinity for lime; a brisk effervescence ensues, which is produced by the disengagement of the carbonic acid which a.s.sumes the state of gas immediately upon being set free. This gas, incapable of being condensed into the solid or liquid form by any degree of cold or of pressure hitherto known, unites to about its own bulk of water, and thereby forms a very weak acid. It may likewise be obtained in great abundance from saccharine matter in fermentation, but is then contaminated by a small portion of alkohol which it holds in solution.

As charcoal is the radical of this acid, we may form it artificially, by burning charcoal in oxygen gas, or by combining charcoal and metallic oxyds in proper proportions; the oxygen of the oxyd combines with the charcoal, forming carbonic acid gas, and the metal being left free, recovers its metallic or reguline form.

We are indebted for our first knowledge of this acid to Dr Black, before whose time its property of remaining always in the state of gas had made it to elude the researches of chemistry.

It would be a most valuable discovery to society, if we could decompose this gas by any cheap process, as by that means we might obtain, for economical purposes, the immense store of charcoal contained in calcareous earths, marbles, limestones, &c. This cannot be effected by single affinity, because, to decompose the carbonic acid, it requires a substance as combustible as charcoal itself, so that we should only make an exchange of one combustible body for another not more valuable; but it may possibly be accomplished by double affinity, since this process is so readily performed by Nature, during vegetation, from the most common materials.

TABLE _of the Combinations of Muriatic Acid, with the Salifiable Bases, in the Order of Affinity._

_Names of the_ _Resulting Neutral Salts._ _bases._ _New nomenclature._ _Old nomenclature._

Barytes. Muriat of {Sea-salt, having base of barytes { heavy earth.

Potash potash {Febrifuge salt of Sylvius: { Muriated vegetable fixed { alkali.

Soda soda Sea-salt.

Lime lime Muriated lime. Oil of lime.

Magnesia magnesia {Marine Epsom salt. Muriated magnesia.

Ammoniac ammoniac Sal ammoniac.

Argill argill {Muriated alum, sea-salt { with base of earth of alum.

Oxyd of zinc zinc Sea-salt of, or muriatic zinc.

iron iron Salt of iron, Martial sea-salt.

manganese manganese Sea-salt of manganese.

cobalt cobalt Sea-salt of cobalt.

nickel nickel Sea-salt of nickel.

lead lead h.o.r.n.y-lead. Plumb.u.m corneum.

tin smoaking of tin Smoaking liquor of Libavius.

solid of tin Solid b.u.t.ter of tin.

copper copper Sea-salt of copper.

bis.m.u.th bis.m.u.th Sea-salt of bis.m.u.th.

antimony antimony Sea-salt of antimony.

a.r.s.enic a.r.s.enic Sea-salt of a.r.s.enic.

{sweet of mercury {Sweet sublimate of mercury, { { calomel, aquila alba.

mercury { { {corrosive of {Corrosive sublimate of { mercury { mercury.

silver silver h.o.r.n.y silver, argentum corneum, luna cornea.

gold gold Sea-salt of gold.

platina platina Sea-salt of platina.

TABLE _Of the Combinations of Oxygenated Muriatic Acid, with the Salifiable Bases, in the Order of Affinity._

_Names of the Neutral Salts by_ _Names of the Bases._ _the new Nomenclature._

Oxygenated muriat of Barytes barytes.

Potash potash.

Soda soda.

Lime lime.

Magnesia magnesia.

Argill argill.

Oxyd of zinc zinc.

iron iron.

manganese manganese.

cobalt cobalt.

nickel nickel.

lead lead.

tin tin.

copper copper.

bis.m.u.th bis.m.u.th.

antimony antimony.

a.r.s.enic a.r.s.enic.

mercury mercury.

silver silver.

gold gold.

platina platina.

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

SECT. XIX.--_Observations upon Muriatic and Oxygenated Muriatic Acids, and their Combinations._

Muriatic acid is very abundant in the mineral kingdom naturally combined with different salifiable bases, especially with soda, lime, and magnesia. In sea-water, and the water of several lakes, it is combined with these three bases, and in mines of rock-salt it is chiefly united to soda. This acid does not appear to have been hitherto decomposed in any chemical experiment; so that we have no idea whatever of the nature of its radical, and only conclude, from a.n.a.logy with the other acids, that it contains oxygen as its acidifying principle. Mr Berthollet suspects the radical to be of a metallic nature; but, as Nature appears to form this acid daily, in inhabited places, by combining miasmata with aeriform fluids, this must necessarily suppose a metallic gas to exist in the atmosphere, which is certainly not impossible, but cannot be admitted without proof.

The muriatic acid has only a moderate adherence to the salifiable bases, and can readily be driven from its combination with these by sulphuric acid. Other acids, as the nitric, for instance, may answer the same purpose; but nitric acid being volatile, would mix, during distillation, with the muriatic. About one part of sulphuric acid is sufficient to decompose two parts of decrepitated sea-salt. This operation is performed in a tubulated retort, having Woulfe's apparatus, (Pl. IV. Fig. 1.), adapted to it. When all the junctures are properly lured, the sea-salt is put into the retort through the tube, the sulphuric acid is poured on, and the opening immediately closed with its ground crystal stopper. As the muriatic acid can only subsist in the gaseous form in the ordinary temperature, we could not condense it without the presence of water. Hence the use of the water with which the bottles in Woulfe's apparatus are half filled; the muriatic acid gas, driven off from the sea-salt in the retort, combines with the water, and forms what the old chemists called _smoaking spirit of salt_, or _Glauber's spirit of sea-salt_, which we now name _muriatic acid_.

The acid obtained by the above process is still capable of combining with a farther dose of oxygen, by being distilled from the oxyds of manganese, lead, or mercury, and the resulting acid, which we name _oxygenated muriatic acid_, can only, like the former, exist in the ga.s.seous form, and is absorbed, in a much smaller quant.i.ty by water.

When the impregnation of water with this gas is pushed beyond a certain point, the superabundant acid precipitates to the bottom of the vessels in a concrete form. Mr Berthollet has shown that this acid is capable of combining with a great number of the salifiable bases; the neutral salts which result from this union are susceptible of deflagrating with charcoal, and many of the metallic substances; these deflagrations are very violent and dangerous, owing to the great quant.i.ty of caloric which the oxygen carries alongst with it into the composition of oxygenated muriatic acid.

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