J46 **N METALLIC SULPHURET9. 



Copper differs very little from that of 28 to 100 given by 

 Mr. Proust. 

 Fused in char- This sulphuret of copper, being subjected to a very vio- 

 lent fire in a crucible lined with charcoal, was fused, and 

 lost but 2^ per cent of its weight. Its aspect was not al- 

 tered, only a few small globules of copper were perceptible 

 toward the bottom of the button. 



2. Siberian sulphuret of copper from the collection of Mr, 

 Gillet-JLaumont. 



Another spe- This specimen, though in appearance very homogeneous, 

 cinien mixed ^^^ notwithstanding mixed with a great deal of quartz. In 

 tvith quartz. . i ,. • i , 



some places it struck fire with steel. 



Analysis. I separated the copper from the iron by sulphuretted hy- 



drogen. The precipitate, calcined, redissolved, and treated 

 with caustic potash gave me 3 gr. of oxide of copper from 

 fi of the mineral. I found in it no other metal but copper 

 and iron. 



The results were 



Component Metallic copper 47 



P*"'- Sulphur.. ]3 



Siliceous residuum 25 



Lime 7 



Red oxide of iroti 9*3 



101-3 

 Proportions of It is to be observed here, that the presence of the diffe- 

 metal'mn^af- '"^'^^ substances foreign to the sulphuret of copper did not 

 fected by fo- affect the proportions of the copper to the sulphur, which 

 Sces"^" ^^ evidently that of 100 to 28. The iron pfobably is not 



combined with the sulphuret, but with the silex and lime 



forms its gangue. 



Copper pyrites. 



Pyritous cop- I. Copper pyrites of Sainbel from the collection of the 

 ^^^' Council of Mines. Spec, gravity 4'l6. 



The specimen I subjected to analysis was amorphous, but 

 without mixture of gangue. Its colour was a greenish 

 yellow bronze, I ascertained its composition in two different 

 methods. 



1st 



