acid ; but when added to the fulphureOus acid,a confiderable heat is excited in a few minutes,and a yellow fulphuretted oxyd of tin d preci-pitated.
Concentrated nitrous acid, added to the folu-tion of tin, caufes an immediate extrication ofnitrous gas, fo copious as to be almod explofive,and the folution is compleatly oxygenated.
Oxymuriatic acid is indantly deprived of itspeculiar pungent fmell, by adding a few dropsof the folution, and the oxygen of the acidunites with the tin.
White arfenic, and the arfenic acid, digededwith the folution, are both decompoied, and ablack powder is precipitated, which is arfenicin the metallio ftate.
The red oxyd of mercury is decompofed im-mediately by the folution, and corrofive muriat,by gentle heating; and in both cafes the metalis totally reduced into globules of running mer-cury.
The white oxyds of antimony and zinc arereduced by the folution, and aflume the metal-lic form.
The folutions of fiiver undergo a fimilarchange.
The nitro-muriat of gold,, added to this fo-lution, caufes that purple precipitate defcribedunder the article Gold , and called, after theinventor, Cafiius’s precipitate.
The folutions of highly-oxygenated iron, fuchas the red fulphat, are immediately brought bythis muriat of tin to that ftate in which the metalis in the lowed degree of oxygenation, whichis the reafon why the common yellow mu-riatic acid, that owes its colour to iron, isrendered colourlefs as foon as tin is immerfedin it. The folutions of copper undergo a fimi-lar change.
Thefe phenomena have been already de-fcribed fully, under the articles Copper, Iron ,and Pnijjtc acid.
Hydro-fulphuret of potafh gives a blackprecipitate with this muriat of tin.
Laftly, when a little of this muriat is con-fined with oxygen gas or common air, it addslike the common eudiometrical fubdances, andgradually abforbs oxygen.
This muriat, when heated per fe in a retort,firft gives out water and acid, which carry upa fmall quantity of tin, after which the re-maining muriat quietly fufes in the retort,without further change, till the heat is raifed tolow rednefs; but it then fublimes almod en-tirely, and concretes in the neck of the retort
’ ProBft, * Bertlioilet
in a folid form, leaving only a fmall quantity ofa white oxyd behind, which becomes fixed,owing to a deficiency of acid.
The fublimed muriat does not appear to bechanged by this proc.efs, except by the lofs ofpart of its acid, for by the addition of a littlefrefh muriatic acid, it totally diffolves, and, asbefore, gives a black precipitate with corrofivemuriat of mercury ; fo that it dill remains in alow degree of oxygenation. On the other hand,the muriated fuper-oxyd is volatile at a verygentle heat, as we fliali prefently mention ; fothat didillation furnilhes a ready method of fe-parating thefe two muriats, the fuper-oxydatedfait rifing entirely at a much lefs degree of heatthan that at which the fub-oxydated fait acquiresany volatility.'
When the crydals of the muriated fub-oxydare diflolved in a good deal of water, the folu-tion foon becomes milky, and a confiderable-precipitate is formed. 11 This precipitate is
foluble with eafe in muriatic acid, and this fo-lution gives, as at firft, a black precipitate, withcorrofive muriat of mercury, and with hydro-fulphuret of potafh ; confequently the degree ofoxygenation is not altered. It alfo diffolves innitric acid, and the folution depofits luna cor-nea with nitrat of fiiver, and confequentlycontains muriatic acid. By didillation, in openfire, it gives fome vapour of muriat of tin, andafterwards muriatic acid, and a grey oxyd is leftbehind. This precipitate, therefore, is themuriat with excefs of oxyd, or (what amountsto the fame) the oxyd with deficiency of mu-riatic acid, and would be accurately termed afub-mnriated fub-oxyd; and, on the other hand,the fupernatant liquor contains the metallic faitwith an excefs of acid, fo as to redden litmus.Here, therefore, as in many fimilar indances,(fuch as that of the fulphat of mercury and tur-bith) the dilution of the fait with much watercaufes an unequal reparation of its condituent .parts, the infoluble portion containing muchoxyd and little add, and the foluble portion,the reverfe. By adding muriatic acid, all theprecipitate difappears, and the whole becomesan uniform folution, with excefs of acid: Inall thefe changes the degree of oxydation is not-apparently changed.
The adion of the alkalies ancf alkaline earthson the folution of muriated fub-oxyd of tin, iscurious and complicated. If a few drops ofcaudic potafh, for example, are added to thisfolution, a white precipitate takes place, which,however, is not a pure oxyd of tin, as might b «