Intelligence and Miscellaneous Articles. 313 



ANALYSIS OF THE GRAY COPPER FROM MOURAIA IN ALGERIA. 



M. Ebelmen states that a copper mine, apparently of great im- 

 portance, has been for some time worked at the foot of the defile of 

 Mouraia in Algeria. The veins are composed principally of car- 

 bonate of iron and gray copper ; the latter sometimes occurring in 

 compact masses and sometimes in crystals, the prevailing form of 

 which appears to be a rhombic dodecahedron, but with numerous 

 modifications on the edges and angles. 



The specimens received by M. Ebelmen for analysis contained 

 a great number of very brilliant small crystals of gray copper, on a 

 gangue composed of carbonate of iron and sulphate of barytes. 

 These specimens were digested for some time in warm dilute hy- 

 drochloric acid, which dissolved the carbonate of iron without alter- 

 ing the gray copper, the crystals of which were then readily de- 

 tached. 



Qualitative experiments, conducted in the usual manner, showed 

 that the ore contained sulphur, arsenic, antimony, copper, iron and 

 zinc : lead, bismuth, and mercury were tried for, but not the smallest 

 quantity was found. No notable quantity of silver could be de- 

 tected ; and the fact that M. Berthier found 0*0008 in 1 part of the 

 ore, shows that the silver is very irregularly interspersed through 

 the veins. 



For the quantitative analysis of this ore, M. Ebelmen employed, 

 with a slight modification, the method proposed by M. H. Rose ; 

 and taking the mean of several experiments, he obtained the fol- 

 lowing as the composition of this ore : — 



Sulphur 27-2.5 



Antimony 14'77 



Arsenic 9*12 



Copper 41-57 



Iron 4-66 



Zinc 2-24 



99-61 



If the analysis of this ore be compared with that of gray copper 

 from various localities, the greatest similarity will be found between 

 it and that from Sainte-Marie-aux Mines, which gave M. H. Rose — 



Sulphur 26-83 



Antimony 12*46 



Arsenic 10*19 



Copper 40-60 



Iron 4*66 



Zinc S'Q9 



Silver 0-60 



99-03 

 Annates des Mines, tome xi., p. 47. 



