COPPER. 411 



Bismuth 68-25 or 9 

 Sulphur 31-75 - 4-186 



100-00 



If this sulphuret of Vauquelin exist, (for I have 

 not succeeded in my attempts to form it artifi- 

 cially,) it is evidently a bisulphuret, or a com- 

 pound of two atoms sulphur with one atom of 

 bismuth. 



SECT. V. 



OF THE ATOMIC WEIGHT OF COPPER. 



COPPER forms two oxides ; the red oxide, which Oxides of 

 occurs native, and does not seem capable of 

 combining with acids; and the black, which 

 constitutes the basis of all the cupreous salts. 

 It was shown long ago by Chenevix, and his 

 experiments have been amply confirmed by 

 succeeding researches, that the black oxide con- 

 tains exactly twice as much oxygen as the red ; 

 and I shall show immediately, that if we reckon 

 the weight of an atom of copper to be 4, then the 

 composition of these oxides is as follows : 



COPPER. OXYGEN. ', 



1. Red oxide 8 + 1 or 2 atoms copper + 1 atom oxygen. 



2. Black oxide 4 + 1 or 1 atom copper + 1 atom oxygen. 



I shall therefore distinguish the black oxide by 



