258 
SELECTED ARTICLES. 
monia produces, in a solution of corrosive sublimate, the am- 
moniuret of mercury, discovered by Fourcroy and examined 
by Guibourt. 
Dumas says that by treating the ammoniacal precipitate by 
caustic potassa this ammoniuret is obtained. As my results 
accord with those of Rose, detailed in his paper, I shall only 
give the composition of the ammoniuret. Messrs. Rose and 
Grouvelle have proved satisfactorily that fused corrosive sub- 
limate absorbs gaseous ammonia, and is by its action convert- 
ed into a white mass, the composition of which is: 
4(2Ch4-Hg)4-4NH^. 
JLction of a solution of ammonia on calomel. 
Mr. Hennel states that the result of the decomposition of 
calomel b)'' water of ammonia is a black powder, containing 
mercury 96 + oxygen 4. 
I have arrived at a different conclusion. Exposed to 
a heat in a tube, the black powder gave traces of water, 
nitrogen, ammonia, and a mixture of calomel and mercury; 
148.15 grains of calomel boiled with an excess of ammonia, 
gave 141.92 grains of the black powder, and the liquid 
acidulated and precipitated by nitrate of silver, gave 44.44 
grains of dry chloride. 
I repeated this analysis, and give the mean of the two: ca- 
lomel being a compound of, 
Hg85.117 + Chl4.883, 
The composition of the black powder is: — 
Mercury, 88.91 
Chlorine, 7.95 
Other substances, 3.14 
100.00 
To determine the quantity of ammonia in it, I put 66.43 
grains into a small matrass to which was fitted a bent tube. 
