OF PALLADIUM AND PLATINUM. 
277 
per cent., having lost 14-62 of water. By a red heat it gave off oxygen, and was re- 
duced to 44-846 grains, or 79’43 per cent. 
These results placed together for comparison give, — 
A. 
J 5*51 
84-49 
B. 
C. 
D. 
16-04 
1551 
14-62 
664 
7-04 
5-95 
77'32 
77-45 
79-43 
Expelled by a moderate heat . 
Expelled by a red heat . . . . ^ 
Residual black powder . . . . J 
The material (6 to 7 per cent.) expelled by a red heat is oxygen gas, but I found, 
by . tl i ialf5 coaducted after the above results were obtained, that neither is all the ma- 
teria expel ed by a moderate heat merely water, nor is the residual black powder 
metallic palladium. 
E. To determine the nature of the black powder which remains after the moderate 
igmt.on of the oxide, 51-346 grains of it were introduced into a tube of Bohemian 
g ass, and heated m a current of dry hydrogen gas ; it became of itself brightly red- 
hot, water was abundantly, almost explosively formed, and the powder assumed at 
once a gray metallic aspect. It then weighed 47-165 grains, or 91-85 per cent. 
F. To control this result another portion of the black powder, obtained from a 
different portion of oxide, was heated in the same way in hydrogen gas. From 46-300 
grains there remained 42-952 grains of metal, or 9272 per cent. 
1 li e T uantl ty of oxygen thus shown to be combined with the metal in this black 
powder is almost exactly half that which the protoxide should contain. It must there- 
fore be considered as suboxide of palladium, at least provided it be not a mixture of 
metal and protoxide, which shall be discussed further on. I shall here only compare 
the experimental results with those given by the formula Pd 2 Cl for its composition. 
■n i . „ Experiment. 
Pd 2 = 106-6 93-02 91*85 92*72 
O = 8-0 6-98 
8-15 
7*28 
1 14 '6 100-00 100-00 100-00 
The mean quantity of black suboxide obtained by the moderate ignition of the 
hydrated oxide as already found, is 78'07, and this is shown by the latter experiments 
to contain 72 60 of metal ; excluding therefore for the moment, the question whether 
anything but water is first driven off, we find that the oxide of palladium may be ob- 
tained anhydrous, that by gentle ignition it abandons one-half of its oxygen and 
leaves a black powder, suboxide, which may be totally reduced to the metallic state 
by violent ignition or by hydrogen gas, at incipient redness. 
The mean quantity of suboxide furnished from 100 of dry protoxide, in the above 
described three analyses, may be thus compared with theory:— 
p r l 0—11 a J he017 n o 4- Experiment.— Mean of B, C, D. 
rd 2 U — 114*6 93-47 78*07 9227 
0 ~ 8 ‘° 653 6-54 77 3 
1226 100-00 
84-61 100-00 
