CLOUD, ON PALLADIUM FOUND IN GOLD. 411 



inoxidable metals; and, in this respect, on a par with gold, sil- 

 ver, and platinum; and that it has been found in a native 

 combination with gold; without the presence of platinum, or 

 any other metal. 



Gold has never been found pure in nature; it has hitherto 

 always been found alloyed with silver or copper; mostly a 

 combination of both, and frequently other metals. The gold 

 which was the subject of my experiments, appears to have 

 been alloyed with palladium only; if any of the other known 

 metals had been present, except silver and platinum, they would 

 have been indicated by preliminary experiment 2d. — Silver 

 would have been discovered by experiment 1st; and platinum 

 by experiment 4th. It is self-evident, that this alloy was native; 

 for no man would have been at the trouble and expense to 

 purify the gold and separate the palladium from platinum, the 

 only source from whence palladium had been heretofore obtain- 

 ed; and where it exists only (agreeably to Doctor Wollaston's 

 experiments, confirmed by my own,) in the proportion of one 

 half of one per cent., merely for the purpose of combining 

 them with an intention of fraud; as none of the metals injures the 

 colour of gold so much, and renders it so suspicious as palladium; 

 and which would necessarily lead to a detection of the imposi- 

 tion. If fraud therefore had been intended, platinum would 

 have answered the purpose much better; as it is not separated 

 from gold by the usual process of assaying. 



No. LXII. 



Observations on the Geology of the United States, explanatory of a 

 Geological Map. By William Maclure. 



Read January 20th, 1S09. 



NECESSITY dictates the adoption of some system, so 

 far as respects the classification and arrangement of names 

 the Wernenan appears to be the most suitable, First, Because 

 it is the most perfect and extensive in its general outlines, and 



