CHAP. XVI. 



OF THE SULPHURETS. 



IN the preceding chapters, the composition of 

 several of the metallic sulphurets has been no- 

 ticed, but it may be acceptable to the reader to 

 take a general view of this important class of 

 bodies. This will be the subject of the present 

 chapter. 



1. Sulphuret of potassium. Gay-Lussac first 

 showed that when sulphur and potash are heated 

 together, a portion of the sulphur is acidified at 

 the expense of the oxygen of the potash, and 

 that the compound formed is a mixture of sul- 

 phate of potash and sulphuret of potassium.* 

 This view of the matter was further confirmed 

 by Vauquelin.t But for by far the most impor- 

 tant set of experiments on the subject, we are 

 indebted to Berzelius, whose paper on the Alka- 

 line Sulphurets, published in 1821,} threw a new 

 and unexpected light over this department of 

 chemistry. 



Berzelius put a quantity of sulphate of potash 

 into a glass tube, and after having heated it to 



* Ann. dc Cbiin. LXXVIIJ. 86. f Ann. dc Chim. ct de Phys. VI. ,}. 

 \ Kong. Vctcnsk. A cad. Hand. 1821. p. 80. 



