OF PALLADIUM AND PLATINUM. 
301 
stituents are directly combined, the loss must necessarily be nitrogen and hydrogen 
in the proportions to form ammonia. This constituent, therefore, was not directly 
estimated; the analyses showing that the brownish yellow powder consists of an 
equivalent of perchloride of platinum united to an equivalent of ammonia. 
This substance is not by any means always formed by the action of water of am- 
monia upon a solution of chloride of platinum ; on the contrary, it is difficult to obtain 
it unless by using both solutions very weak, and by having the platinum quite free 
from muriatic acid in excess. In the great majority of cases, this first product is 
either rendered impure by the passage of a portion into the second stage of the re- 
action, or else by the precipitation of the double chloride of platinum and ammonium 
which is generated at the same time. With moderately weak solutions, the platinum 
being in excess, and avoiding too much washing of the precipitate, the substance may 
generally be obtained pure. 
B. When the solutions of chloride of platinum and ammonia are boiled together, 
the precipitate rapidly assumes a remarkable fawn colour. In this state it is insoluble 
in water. It dissolves in muriatic acid, producing a yellow liquor. When heated, it 
gives off chlorine and muriatic acid gases, water, a trace of sal-ammoniac, and leaves 
metallic platinum. 
The analysis of this body was effected as follows : — 
I. 27*999 grains ignited with an excess of carbonate of soda, gave by the same 
mode of treatment as that described in paragraph A, 12*332 of platinum, being 44*24 
per cent., and 47*365 of chloride of silver, equivalent to 41*94 in 100. 
For the determination of the hydrogen and nitrogen, the same methods were em- 
ployed as in the analyses of organic bodies, and the details of which need not be 
inserted. 
20*064 grains burned with oxide of copper, gave 19*386 of water, or 2*17 per cent, 
of hydrogen. 
20*049 grains of substance produced 4*29 cubic inches of dry pure nitrogen, equi- 
valent at standard temperature and pressure to 1*420 grain, or 7*09 per cent. 
II. Another quantity of substance prepared at a different time and at a much lower 
temperature, gave the following result : — 
23*599 grains ignited with carbonate of soda, gave by treatment with nitric acid 
and nitrate of silver 40*223 chloride of silver, equivalent to 41*20 of chlorine per 
cent., and left 10*507 of platinum, equal to 44*47 in 100. 
The hydrogen being determined, as in the former case, there was obtained from 
24*925 grains of substance 5*170 of water, equivalent to 2*30 of hydrogen per 
cent. 
In this instance the nitrogen was not determined. The formula to which these re- 
sults lead is very remarkable, and will hereafter give origin to some observations ; for 
