SULPHURETS. 199 



18. Sulphuret of copper. I have already Copper, 

 shown in a former chapter of this work, that 

 there are three sulphurets of copper : 

 (1.) Disulphuret, composed of 



2 atoms copper . 8 



J atom sulphur , . 2 



10 



This sulphuret is obtained when sulphate of cop- 

 per is heated in a charcoal crucible, as Berthier 

 has shown. During the process, one-half of the 

 sulphur in the salt makes its escape. It is ob- 

 tained likewise when sulphur and copper are 

 heated together : the combination is accompa- 

 nied by combustion. This sulphuret has a bluish 

 black colour, and occurs native, being the glance 

 copper ore of mineralogists. 



(2.) Sulphuret of copper has not yet been 

 formed artificially ; but it exists in copper py- 

 rites, which H. Rose has shown to be a com- 

 pound of 



1 atom sulphuret of copper 6 

 1 atom sulphuret of iron 5 5 



This sulphuret is a compound of 



1 atom copper . 4 



1 atom sulphur . 2 



Ann. dc Chim. ct dc Phys. XXV. 197. 



N 1 



