322 Dr. Wollaston on the Discovery of Palladium, 
§ IV. Separation of Palladium. 
There was no difficulty in ascertaining the presence of lead 
as one of the ingredients of this precipitate, by means of mu- 
riatic acid, which dissolved lead and iron and a small quantity 
of copper. It was equally easy to obtain a larger portion of 
copper by dilute nitrous acid, with which it formed as usual a 
blue solution. But when I endeavoured to extract the whole 
of the copper by a stronger acid, it was evident, from the dark 
brown colour of the solution, that some other metallic ingre- 
dient had also been dissolved. I at first ascribed this colour 
to iron ; but, when I considered that this substance had been 
more slowly acted , upon than copper, I relinquished that hy- 
pothesis, and endeavouring to precipitate a portion of it by a 
clean plate of copper, I obtained a black powder adhering to a 
surface of platina on which I had placed the solution. As 
this precipitate was soluble in nitric acid, it evidently consisted 
neither of gold nor platina ; as the solution in that acid was of 
a red colour, the metal could not be either silver or mercury ; 
and as the precipitation of it by copper excluded the supposi- 
tion of all other known metals, I had reason to suspect the 
presence of some new body, but was not fully satisfied 
of its existence until I attempted the precipitation of it by 
mercury. 
For this purpose I agitated a small quantity of mercury in 
the nitrous solution previously warmed, and observed the mer- 
cury to acquire the consistence of an amalgam. After this 
amalgam had been exposed to a red heat, there remained a 
white metal, which could not be fused before the blow pipe. It 
gave a red solution as before in nitrous acid ; it was not 
