On a mw fulmlnaling Mercury. 9^ 



yellowiih-brown powder, nearly as it would have done from 

 a fol'.ition of nitrat of mercury. This precipitate was fepa* 

 rated by a filter, and the filtrated liquor evaporated to a dry 

 fait, which was vvaftied with alcohol.. A portion of the fait 

 being re-fufed by this menftruum, it was Separated by filtra- 

 tion, and recognifed, by all its properties, to be nitrat of pota{h. 

 The alcoholic liquor was likewife evaporated to a dry fait, 

 which, upon the affufion of a little concentrate fulphurie 

 acid, emitted acetous acid, contaminated with a feeble fmell 

 of nitrous acid, owing to the folubility of a fmall portion of 

 the nitre in the alcohol. 



Section XII. 



The fulphurie acid afts upon the powder in a remarkable 

 manner, as already has been noticed. A very concentrate 

 acid produces an explofion nearly at the inftant of contadi, 

 on account, I prefume, of the fudden and copious difengage- 

 ment of caloric from a portion of the powder which is de- 

 compofed by the acid. An acid fomewhat lefs concentrate 

 iikewife extricates a confiderable quantity of caloric, with a 

 good deal of gas ; but, as it effedls a complete deconipofi- 

 tion, it caufes no explofion. An acid diluted with an equal 

 quantity of water, by the aid of a little heat, fepa'rates the 

 gas fo much lefs rapidly, that it may with fafety be collefted 

 in a pneumatic apparatus. But, whatever be the denfity of 

 the acid, (provided no explofion be produced,) there remains 

 in the fulphurie liquor, after the feparation of the gas, a 

 white uninflammable and uncryftallifed powder, mixed with 

 fome minute globules of quickfilver. 



To eftimate the quantity, and obferve the nature, of this 

 uninflammable fubftance, I treated lOO grains of the fulmi- 

 nating mercury with fulphurie acid a little diluted. The gas 

 being feparated, I decanted otf the liquor as it became clear, 

 and freed the infoluble powder from acid, by edulcoraiion 

 with diftilled water; after which I dried it, and found it 

 weighed only 84 grains ; confequently had loil J 6 grains of 

 .its original weight, Sufpeiling, from the operation of the 

 nitric acid in the former experiment, that thefe 84 grains 

 (with the exceptiozi of the quickfilver globules) were oxalat 

 Ea of 



