155 



to be correct, (h^h 101,4,) and there is no other subsulphate ; 

 the pure turbith, no matter how prepared, possessing that 

 constitution. By the action of ammonia on persulphate, or 

 on turbith mineral, there is generated a white powder, 

 which was submitted to most careful analysis, and gave the 

 formula ngo.sos + 2Hgo 4- h^.nh2. was found. The proof that 

 the fourth atom of mercury in this body is not an oxide, is full 

 and positive, and hence Dr. Kane no longer retains the pa- 

 rallehsm of theories used in his former memoir, as the ab- 

 sence of oxygen may now be considered as fully proved. 



The crystallizable nitrate of the red oxide of mercury 

 has been found ^05 + 2ug o + ^ ho, as the younger Mitsch- 

 erslich had stated ; and Dr. Kane shows that there are two 

 basic pernitrates, of which the one, yellow, is similar in com- 

 position to the basic nitrates of copper and bismuth, that is, 

 HO.NO5 -h 3 pi^ o, and the second, of a brick red colour, he is 

 disposed to consider as NO5 + 6 h^ o, though it was found 

 exceedingly difficult to decide whether the compound did 

 not retain a trace of water. : 



It is known that for the composition of the white precipi- 

 tate, which is given by ammonia with pernitrate of mercury, 

 different results had been obtained by Mitscherslich and Sou- 

 beiran. These discrepancies have been reconciled by the 

 discovery that there are at least two, perhaps three precipi- 

 tates, almost identical in colour and properties, produced in' 

 this reaction, but which diiFer remarkably in their chemical 

 constitution. When the solutions are cold, and the ammonia 

 not in excess, the white precipitate has the composition 

 NH3.NO5 4- Sngo, the formula obtained by George Mitschers- 

 lich, but if the liquor be warmed, it becomes ag.o.^o^ -f- 

 2ugo 4-H^NH2. This modification is evidently that which 

 was analyzed by Soubeiran, for he found one atom of acid, 

 one of ammonia, and four of mercury, which ratio is quite trile. 

 It will be at once seen that the former body corresponds to" 



b 



