12 Oji the Combinations of different Metals, &c. 



the oxide of silver is partially reduced by thp solulinn of 

 stannane ; and an oxide of tin is thrown down in mixture 

 With the horn silver from the liquor t)f Lib4vius. 



M. Proust, to whom we are mdebted for very excellent 

 invi.'5tig<?tion.s of the d'Bcrcnt combinittions of copper and 

 tin, first discovt-rtd a submiirial of tin. He found that a 

 ?o!ulion (if pot.iih precipitated from the solution of muriat 

 of tin this coiiipo'ind, and not the pure gray oxide of tin. 



I have obtained it by his method, and all its properties 

 which I have observed are perlcctiy agreeable to its sup- 

 posed composition. 



ft is decomposed by a red heat. Sul)jected to distillation 

 in a small bent glass tube connected with mercury, no gas 

 was produced, water containinij muriatic acid and muriat 

 of tin was expelled, and a sublinsate like stannane was 

 formed, and the fixed residue was gray oxide of tm. 



It eflcMvesces viclently with nitric acid; and strong sul- 

 pliuric acid expels from it muriatic acid fumes. 



It ilissolves without efiervescence in the muriatic and 

 acetic and in the ddule, nitric, and sulphuric acids ; and 

 all these acid solutions, as they give a black precipitate 

 with a soUi'ion of corrosive subhmaie, appear to contain 

 tiiC tin in tlie state of gray oxide. 



The complete analysis of this suhmuriat of tin is diffi- 

 cult. The oxide it contains cannot be accuratelv separated 

 by potash, nor can nitrat of silver be employed to ascertain 

 the proportion of muriatic acid. 



I have found 50 grains of it, dissolved in muriatic acid, 

 to afford, when precipitated by zinc, 31 grains of metallic 

 tin. Now as this submuri it is similar to the subinuriat of 

 copper, the analocy being imperfect only in the latter con- 

 taining the peroxide, and the former the protoxide, it is 

 natural to infer that the proportion of nniriatic acid is si- 

 milar in both. But the proportion of muriatic acid in the 

 suhmuriat of cojiper is apparently half t f that which exists 

 in the muriat : hence, supposing the composition of the 

 suhmuriat of tin to be similar, 100 of it will consist of 

 70 4 gray oxide 

 1 Q'O muriatic acid 

 10-6 water 



1000. 

 Piobability alone can be attached to this estimate. I 

 have not given the calculations by which it was made, as 

 ihcir data are liable to objection. 



[To be continued.] 



III. On 



