and native Palladium from Brasil. 191 
other, with the interstices extremely clean, and free from any 
degree of tarnish. 
The first portion that I employed for solution was taken 
without any selection, and being digested with a small quan- 
tity of nitro-muriatic acid, two of the grains were acted on 
much more rapidly than is usual with platina, and seemed to 
give a redder colour than that metal alone. These grains 
were consequently taken out, washed, and reserved for sepa- 
rate examination, and the solution was allowed to proceed till 
the rest were entirely dissolved. By the addition of muriate 
of ammonia an abundant precipitate was formed of a bright 
yellow colour. This precipitate was evidently platina, and its 
colour satisfied me that the grains had not been brought into 
their present state from Peruvian platina by means of arsenic ; 
for where arsenic has been employed, I have observed that 
the iridium contained in that ore is rendered more soluble 
than before, and thence communicates its red colour to the 
precipitate. 
From the grains thus examined, there appeared not to be 
any iridium dissolved, nor any black powder containing iri- 
dium undissolved. 
I next endeavoured, by prussiate of mercury, to ascertain 
the presence of palladium, but though a precipitate which 
occurred indicated a certain quantity, it remained doubtful 
whether it was derived from the grains of platina themselves, 
or from the two small fragments that had been in part dis- 
solved before they were separated from the rest. 
By addition of ammonia to the solution, no iron was preci- 
pitated ; and when the solution was afterwards allowed slowly 
to evaporate, I could discern no crystals or colour that I could 
C c 2 
