124 
Mr. Chenevix on the Action of 
more easily than platina by nitro-muriatic acid ; and the solu- 
tion when nearly in a neutral state gives a copious metallic 
precipitate, ( yet not equal to the quantity employed, ) when 
boiled with a solution of green sulphate of iron. 
Exper. 2. When a mixed solution of platina and mercury is 
precipitated by metallic iron, a quantity equal to the sum of the 
former metals is generally obtained. iMter nitric acid has been 
boiled for a long time upon the precipitate so formed, the original 
weight of platina, together with a considerable increase, remains 
behind, nor can nitric acid sensibly diminish it. It yields more 
easily than platina to the action of nitro-muriatic acid, and its 
solution in that acid, when neutralized, gives a precipitate, as 
in the former experiment, by green sulphate of iron. If this 
precipitate be exposed to a strong heat after it has been boiled 
with nitric acid, it loses a great part of its weight, and the 
platina alone will generally be found to remain. 
Exper. 3. When a quantity of ammoniacal muriate of platina 
is treated according to the method of Count Mussin Pushkin 
to form an amalgam, and, after being rubbed for a considerable 
time with mercury, is exposed in a crucible to a heat gradually 
increased till it becomes violent, a metallic powder remains in 
the crucible. This powder is acted upon by nitro-muriatic acid, 
and when the solution is neutralized, a copious precipitate is 
formed upon the addition of green sulphate of iron. This effect 
takes place even after the metal has been fused in the manner 
described in the former part of this Paper. 
Exper. 4. If sulphur be added to the ingredients recom- 
mended by Count Mussin Pushkin, and the whole treated as 
in the last experiment, the quantity of precipitate caused by 
green sulphate of iron in the nitro-muriatic solution of the 
