On Aluminous Sulphates.— New Triple Sail. 275 



tury, difengagres a great deal of rutilating vapour by the ful- 

 phiiric and^nuric acids. It tinges the flcin of a dark purple 

 colour: while nitrate very much oxidated dyes it black, and 

 nitrate little oxidated, like the nitrite of the fame nature, does 

 not change the colour of animal matters. It retains longer 

 in the open air its nature of nitrite than the alkaline nitrites, 

 which fpeediiy refume the nature of nitrates. Alkahne ni- 

 trites, and particularly deliquefcent nitrites, may be prepared 

 without difficulty by impregnating the folutions ot nitrates, 

 &c. with nitrous gas, which eafily condenfesin them. 



The author, tolerminate his labour, is to occupy himfelf 

 with the muriates of mercury, of which he has difcovered a 

 new kind, and with the fulpliurets of the fame metal. _ It 

 would be a pity that the important and numerous funftions 

 entrufted to him, (liould oblige him to difcontinue thefe ufe- 

 ful refearches ; but, happily for the intereftof fcience, people 

 feldom abandon a career which they have long purfued with 

 fuccefs. 



On Aluminous Sulphates. 

 S. Seguin, having been employed in continued refearches 

 on the different ftates of the fulphates of alumine, read on 

 that fubjecl a memoir, in which he proves That the acid 

 fulphate of alumine pure, that is to fay when free from thofe 

 fubltances which it is neceflary to add to it in order to mak** 

 it cryftiUize, does not, in any cafe, decompofe the muriate 

 of foda— That alum, the caufe of the cryllallization of 

 which is the fulphate of potafli, does not experience decom- 

 pofition from the muriate— That alum, the caufe of the 

 cryftallization of which is the fulphate of ammonia, receives 

 no alteration from the muriate of foda, when it contains only 

 the quantity of fulphate of ammonia indifpenfably neceflary 

 far its cryft'allization — Finally, that alum, containing more 

 fulphate of ammonia than the quantity neceflliry for its cryf- 

 Ullization, is the only fait which experiences alteration by 

 the muriate of foda ; and that this alteration is conlined 

 merely to the decompolition of the fulphate of ammonia 

 which it contains in exccfs. 



A New Triple Salt. 

 There refults from the decompofiiion above mentioned, on 

 the one hand muriate of ammonia, and, on the other, a 

 triple fait, compofed of fulphuric acid, foda and ammonia, 

 and whicli had not been before remarked. 



A mixture cither of the fulphate of ammonia and muriate 



of foda, or of fulphiile of foda aod fulphulc of ammonia, 



S 3, product* 



