304 SALTS. 



be made by fusion of the same materials. The proto- 

 sulphuret can be made from the sulphate, by reduction 

 with hot carbon. Certain other soluble sulphurets may 

 be prepared in the same manner. 



766. MILK OF SULPHUR. This form of 



How is milk of , . . . 



sulphur pre- sulphur, like that just mentioned, is used 

 pared? ^ me( jicine. It may be prepared from a 



solution of the liver of sulphur, by the addition of an 

 acid. The latter combining with the potassa, the sul- 

 phur is precipitated in a state of the finest division, 

 giving to the liquid the appearance of milk. 



767. OTHER SULPHURETS. The natu- 

 of the other ral sulphurets have colors different from 

 sulphurets? ^ Q similar compounds when produced, as 

 above, by precipitation. Thus, the natural sulphuret 

 of lead, or galena, has the color of the metal ; that of 

 mercury is red, and is called cinnabar ; that of zinc, 

 called zinc blende, and by miners, black jack, is of dif- 

 ferent shades brown, yellow and black. The precipi- 

 tated sulphuret of mercury turns red by sublimation, 

 and in this state forms the familiar pigment called ver- 

 milion. Sulphuret of iron, which is employed in 

 making hydrosulphuric acid, may be prepared by hold- 

 ing a roll of sulphur against a rod of iron previously 

 heated to whiteness. This may be readily done in any 

 blacksmith's shop. The fused sulphuret falls in glo- 

 bules from the surface of the iron. 



