so 



Aneni«. 



Component 

 l^arts of the. 

 •rr. 



Klaproth's 

 analyses. 



ANALYSIS OF A GRAY COPPER ORE. 



6. When the 12*6 grains of yellovirisb brown matter de- 

 tached from the tube were digested in hot potash^ley, the 

 whole was dissolved, except a tine blackish powder, which 

 weifjhed 1 grain, and was arsenic. The dissolved portion 

 1 considered as sulphur, 



10. The potash solution, being mixed with nitric acid, 4 

 grains of swlphnr fell. The remaining 7*^ grains must 

 have been converted into sulphuric acid, by the action of 

 the nitric acid. Accordingly, muriate of barytes occasion- 

 ed a copious precipitate, 



11. The 84 grains of roasted ore being reduced to a fine 

 powder, mixed with half their weight of pounded charcoal, 

 and roasied a second time in a glass tube, one grain of sul- 

 phur sublimed. But the tube breaking before the roai>ting 

 had been continued long enough, the process was com- 

 pleted in a crucible. The roasted ore weighed 70 grains. 



12. Fiom the preceding analysis, we learn that the con- 

 stituents of the Airthrey ore are as follows: 



Iron, 45.5 



Copper, 17*2 



Arsenic, 14*0 



Sulphur, 12-G 



Water, 3*4 



Foreign bodies, .... 6.9 



99-6 

 Loss, ••• '4 



100-0 

 If we suppose the water and the earthy residue to be only 

 accidentally present, then the only essential constituents are 

 the first four, and the ore would be a compound of 



Iron, 51*0 



Copper, 19-2 



Arsenic, 157 



Sulphur, 14*1 



100-0 

 If we compare this analysis with several analyses of gray 

 copper ore, lately published by Klaproth, we shall find, 

 that the constituents are the same in both; but the propor- 

 tions 



