EED SILVER ORE. 



85 



bulb-tube, over a large spirit-lamp or gas-burner, in a 

 stream of dry hydrogen, as long as any sulphuretted 

 hydrogen is formed ; all the sulphur is thus expelled, 

 in combination with hydrogen. The conclusion of the 

 operation is also indicated by a sort of coruscation 

 which takes place, and the antimonide of silver is left in 

 the form of a perfectly bright, smooth, movable globule. 

 The tube is allowed to cool slowly, weighed, and 

 placed in communication with an apparatus for the 

 evolution of chlorine, in a current of which the anti- 

 Fig. 11. 



monide of silver is fused, until no more pentachloride 

 of antimony is volatilized, and pure fused chloride of 

 silver remains. The latter is then treated as in the 

 case of gray copper-ore. 



The antimonide of silver may also be oxidized by 



common salt ; to prepare the arseniferons compound, 3 parts of 

 sulphide of silver and 1 part of yellow tersulphide of arsenic, or 

 32.4 parts of powdered silver 9.6 parts of sulphur, and 7.5 parts 

 of arsenic are fused together in a glass tube closed at one end. 

 Combination takes place with incandescence. 



