344 Elements of Mineralogy. 



tained in it by the marine acid, and copper 

 when any by iron. To feparate cobalt from 

 nickel when the cobalt is in confiderable quan- 

 tity, Mr. Gerhard advifes to drop a faturate 

 folution of the roafted ore in nitrous acid, into 

 liquid volatil alkali : the cobaltic part is in- 

 ftantly re^diffolved, and affumes a garnet co- 

 lour ; when filtered a grey powder remains 

 on the filter, which is the nickel : the cobalt 

 may be precipitated from the volatil alkali by 

 any acid. Mem. Berlin^ 1779, p. 17 and 18. 

 cobalt may alfo, in fome meafure, be fepa- 

 rated from nickel, by melting it with three 

 times its weight of liver of fulphur ; the co- 

 balt will be taken up, and may be feparated 

 by lixiviation. 2 Bergm. 244. 



7. In the dry way a regulus is obtained 

 from the ores of nickel by long continued 

 torrefa&ion, which expels much of the ful- 

 phur and arfenic, and then melting the green 

 calx thus obtained, with twice or thrice its 

 weight of black flux in an open crucible co- 

 vered with common fait by the ftrongeft fire 

 of a fmith's forge, a regulus is found, which 

 amounts to from 30 to 50 per cent, of the 

 weight of the green powder : this regulus 

 ftill contains fulphur, arfenic, cobalt and 

 iron j its further depuration is very laborious, 

 and may be feen in the fecond volume of Mr. 

 Bergman's works. 



8. It 



