Ol» FIATINA AND NAflTB PAtLADItJM FROM BRASIL. ^ i 



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 1 believe never contains 

 (in the ore itself) the smallest quantity of gold. 



In this experiment also, 1 tried to detect the existence of Palladium. 

 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 The gold al- 

 Peruvian nor Brasilian grains of platina contain any silver, ^J^^ ^""^ " * 

 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 Native palla- 

 solution, next claimed my attention, and evidently deserved 

 a careful examination. They Mere each placed in a drop of 

 nitric acid, and each communicated a deep red colour, 

 which, by the tests of prussiate of mercury and green sul- 

 phate of iron, I was satisfied arose from palladium. The 

 smaller fragment was then divided, and one portion allowed 

 to remain in the acid till it seemed completely dissolved, and 

 the other examined by the blowpipe. The utmost heat 

 that could be given appeared to have no effect ; but when a 

 small piece of sulphur was applied to it, it fused instantly; 

 by continuance of the heat, it parted with the sulphur, and 

 became completely malleable. In short, it perfectly resem- Nearly pur«. 

 bled palladium ; and it retained its brilliancy in cooling, I 

 judged it to be nearly pure. 



But as the surfaces which had been acted upon by nitric AiForded a 

 acid had a degree of blackness, that might be owing to some ^^^^^'^ "^' 

 insoluble impurity, I have since that time dissolved the 



larger 



