3 9 s Dr. Wollaston on Platina 
ascribe to the presence of rhodium. In short, it seemed that 
these grains are really native platina nearly pure. 
In order to discover whether the grains themselves con- 
tained any portion of gold, I selected three of the largest 
weighing together eight grains and a half ; and after a solu- 
tion and precipitation, as before, by muriate of ammonia, I 
added a solution of green sulphate of iron, and obtained a 
precipitate of gold. It was, however, far too small in quan- 
tity to be estimated with correctness, but certainly did not 
exceed the of a grain. This, it is to be observed, is an- 
other circumstance in which the present mineral differs from 
the Peruvian ore of platina, which I believe never contains (in 
the ore itself) the smallest quantity of gold. 
In this experiment also, I tried to detect the existence of 
palladium in the solution, and by prussiate of mercury again 
ascertained its presence ; but it was in too small quantity for 
estimating the proportion it bore to the whole mass. 
It may deserve to be remarked, that though neither the 
Peruvian nor Brasilian grains of platina contain any silver, yet 
the gold which accompanies them is in each instance so much 
alloyed with silver, that from about thirty small scales of 
gold picked from Peruvian platina, weighing two grains, I 
obtained as much as four tenths of a grain of silver, or one 
fifth part of their weight. 
Native Palladium . 
The two fragments, that had been separated from the first 
solution, next claimed my attention, and evidently deserved 
a careful examination. They were each placed in a drop of 
nitric acid, and each communicated a deep red colour, which. 
