SULPHURETS. 19> 



for it dissolves in acids without the deposition 

 of any sulphur. 



13. Sulphuret of cerium. This sulphuret is cerium, 

 still unknown. When a solution of cerium is 

 precipitated by a hydrosulphuret, the precipi- 

 tate is in the state of an oxide, and the sulphu- 

 retted hydrogen gas escapes. When sulphur is 

 heated with peroxide of cerium, protosulphate of 

 cerium is formed, and perhaps some sulphuret. 

 The mass has a green colour. 



14. Sulphuret of zinc. When a solution of zinc, 

 sulphate of zinc is precipitated by hydrosulphu- 

 ret of potash, the precipitate is white ; but when 

 heated, it becomes light yellow, In this state it 



is a sulphuret of zinc, similar in its composition 

 to yellow blende. Berthier has shown that this 

 sulphuret is formed likewise when sulphate of 

 zinc is heated in a charcoal crucible. He found 

 that charcoal, in a high temperature, has the pro- 

 perty of decomposing blende bisulphuret of 

 carbon is formed, and zinc sublimes. Sulphuret 

 of zinc dissolves in acids, without depositing any 

 sulphur. It is, therefore, a compound of 



1 atom zinc . . 4'25 

 1 atom sulphur . 2 



6-25 



15. Sulphuret of cadmium. This sulphuret Cadmium, 

 is formed when cadmium and sulphur are heated 



N2 



