34-O Elements of Mineralogy. 



pearance of mifpickel ; it becomes black, and 

 not red by calcination, which dtftinguifhes it 

 from pyrites i it contains fo little fulphur, 

 that none can be extracted from it ; when 

 diflblved in aqua regia, its folution is yellow 

 while cold, but greenifh when boiling, which 

 viciffitude of colour is peculiar to marine co- 

 balt ; it contains much more iron than it does 

 cobalt. 



1 2. In the dry way cobaltic ores, after free* 

 ing them from their matrix by warning, and 

 from fulphur and arfenic by roafting, are re- 

 duced by melting them with three parts black 

 flux in a lined and covered crucible, in a fmith's 

 forge ; the beft ores contain from 60 to 80 

 per cent, of regulus, the worft under 25 per 

 cent. Smalt is reducible in the fame manner, 



13. To eflay the tinging power of cobaltic 

 ores, the roafted ore is melted with three 

 times its weight of pot-am, and five times its 

 weight of pounded glafs or flint, putting in 

 the pot- am firft, then the glafs or flint, and 

 overall the ore. Schejf. 322. 



14. If any bifmuth be contained in the 

 cobalt ore, it will not mix with the regulus of 

 cobalt, unlefs nickel alfo be contained in it, 

 but will fimply adhere to it, and may be fe- 



parated 



