304 Mr. Chenevix’s Enquiries concerning the Nature 
palladium. They were chiefly founded upon two principles: 
disposing affinity, and assimilation. In the one case, I endea- 
voured to present to the metals that compose it, a substance 
which, on account of its affinity for some menstruum necessary 
for their solution, and of their own tendency to combine in the 
proportions stated in Exper. 1, might cause them to unite in the 
form of an insoluble compound. In the other case, I hoped to 
assimilate the properties of each, and, by making them some- 
thing more alike, to place them in the most favourable circum- 
stances for uniting. Exper. 1 was founded on the former, and 
Exper. 8 on the latter of these principles. 
In many instances, when I did not form palladium, I obtained 
a metallic button which was not platina; and, when I did so, it 
always weighed more than the original quantity of platina 
employed. In repeating Experiments 1, 2, 4, 6, 8, 1 1, and 12, I 
seldom failed of having such a substance. No effect of this kind 
took place in any experiment, when mercury was not used along 
with platina ; and the other metals were merely accessaries, in 
promoting their union and precipitation. This is sufficiently 
proved, by the uniformity of the results in different processes, 
whether it was palladium or the substance I now mention which 
was formed. The chief property which distinguishes the latter 
substance from platina, is its density. It is not unusual to obtain 
it of a specific gravity so low as 13; very frequently 15 or 17. 
In the first experiments, I suspected this lightness to be owing 
to some air-bubbles ; but repeated fusion, and comparative ex- 
periments upon platina, soon convinced me of the contrary. 
The augmentation of weight also, which the platina never fails 
of acquiring, proves that this metal has combined with some 
ponderable substance ; and, in fact, the result of these operations 
