148 



Component, 

 parts. 



JN^ean of the 

 two analyses. 



Another spe- 

 eimen. 



Treated with 

 aqua regia. 



Precipitated 

 by muriate of 

 barytes, 



and sulphuret- 

 fed hidrogen. 



Component 

 parts. 



Analysis re« 

 jpeated. 



ON METALLIC SULPHURETSv 



Result, 



Sulphur • . • .35 



Copper • 30*5- 



Metallic iron 33 



Some traces of zinc 



Gangue • • » • • • • • 1 



99-5 

 If we take a mean of the results of these two analyses, W4^. 

 shall have as very probable proportions. 



Sulphur 36 



Copper • 30 



Metallic iron 32 



Gangue i 



2^inc 1 



100 



IL Copper pyrites of BaigoiTy. 



For the two following analyses I employed pieces of ore 

 that were sufficiently pure, though mixed with quartz. 



1st analysis. Five grammes reduced to powder were sub-, 

 jected to the action of nitromuriatic acid. The first resi- 

 duum, weighing 1.72 gr., was reduced to 0*73 of a gr. by 

 calcination. An addition of acid left only 0*54 of a gr., 

 and of these 0*46 were found to be gangue, after thq sul- 

 phur had been burned. 



The muriate of barytes precipitated from the solution 3'fif, 

 gr. of sulphate, corresponding to 0*5 of a gr. of sulphur. 

 The whole of the sulphur therefore was 1*57 gr. 



Sulphuretted hidrogen w^s employed to separate the cop-, 

 per. The brown oxide of this metal, precipitated by pot-, 

 ash, weighed 1*69 gr., and consequently contained 1*35 of 

 metal. The red oxide of iron obtained weighed 2*19 gr,, 

 corresponding to 1*49 gr. of metallic iron. 



Result. 

 Sulphur .............. 31*5 



Copper 27 



Metallic iron 30 



Qangue S'5 



97 

 2d analysis. I treated 5 gr. of the same substance in the 



same 



