SILVER AND GOLD. 53 



sulphur and sublimed as realgar or red sulphuret of arsenic. 

 For its diffusion, see Copper, above. 



6. Antimony and Bismuth. — These metals are obtained by 

 eliquation, or by heating their ores when they flow out from 

 the gangue. We have not yet found important localities of 

 either of these metals, although antimony is inconveniently 

 associated with some Western lead-ores. Bismuth, occurring 

 mostly in the native state, is simply subjected to this operation ; 

 but antimony, being generally found as sulphuret, is eliquated 

 as such, the sulphuret being very fusible. The metal or re- 

 gulus of antimony is then obtained by heating the sulphuret 

 with iron, alkali, &c. which take up its sulphur. As it is of 

 some importance to have it free from arsenic, various processes 

 have been devised to effect the separation, with variable success. 



Antimony free from Arsenic. — To effect this separation ac- 

 cording to Liebig's method, Bensch observes that the presence 

 of sulphuret of iron is necessary, and gives the proportions : 

 100 pts. crude antimony (sulphuret), 42 pts. clean iron filings, 

 10 pts. anhydrous glauber's salt, 2 pts. charcoal, and 2 per 

 cent, sulphuret of iron. After fusion, 16 pts. of the regulus, 

 containing iron, 1 pt. sulphuret of antimony, and 2 pts. soda 

 are kept in fusion an hour, and the regulus, freed from slag, 

 is fused first with 1| and then with 1 pt. soda (without sul- 

 phuret of antimony), each time for an hour, until the slag has 

 a light-yellow color. The passage of the antimony through 

 the crucible is prevented by smearing it previously with moist 

 soda, and then heating it until the soda fuses and glazes the 

 interior. 



7. Silver and Crold. — We place these together, from their 

 similar metallurgic treatment, both in the ore and when puri- 

 fied for commercial purposes. The methods of purifying are 

 partly by fire and partly by acid ; the modes of extraction 

 from their ores are partly by washing, partly by amalgamation 

 with mercury, and recently liquid methods have been proposed- 

 Native gold generally contains silver, the greater part of which 

 is to be separated, being lost by association with a metal of 

 far greater value ; and silver, when obtained from its ores, is 



£2 



