30Z METALS. 94. Cobaltum. 



94. COBALTUM. Bluifh-grey with often a fhade 

 of red, hardifli, very brittle, attrafted by the 

 magnet and itfelf convertible into the magnet, 

 fpccific gravity 8,^150: in a red heat gradu- 

 ally becoming a blue powder which becomes 

 deeper and atlafl a deep black-blue, in a violent 

 heat burning with a red flame, when fufed with 

 borax producing a fine blue glafs : giving a red- 

 difb colour to its folution in nitric acid, and 

 precipitating a blue powder with the addition of 

 potafs, 



nigrum, Inconrpicuous, of a dnl'ky colour, emitting no arfenical 

 vapours when thrown on hot coals. 



. Cobaltum cakiforme. Cron/, miner, 245, 

 Black cobalt. Berkenh./yn. 269. 



Black oxyde or c?1x of cobalt. SchmeiJJer vihu 2. />. 240. 

 Black cobalt ore. Thomfoncbem, ^, p. loj. 



1. Friable, of a loofe earthy confiflcnce. 

 Ochracobalti nigra. WalLfyJi. 2. />. 183. v.rj, a. 

 Loofe black cobalt ore. Kirnxan mmeraU 2, p, 275. 



2. Indurated. 



Cobaltum fcoriaceum. Syf(.nat> x\\, 3. p, 129 ». 4. 

 Cobaltum mineralis. WalLjyfh 2. p. 180. «. 5. 

 Indurated black cobalt ore. Kirijoan miner. 2. p. ZJ^, 



Found in the mines of Great ^Britatn, Juflria, Saxony, Hungary, 

 Germany, &c. either in the ftate of a loofe friable powder, or 

 in veins, or in corroded botryoidal or kidney-form mafles : 

 colour various fhades of brown orblackifh with often a fhade 

 of grey or green : when rubbed with the nail it becomes 

 fliining : it is foluble in muriatic acid : fpecific gravity from 

 3 to 4,000, 



ochraceum. Inconfpicuous, earthy internally, of a paler colour, 

 emitting arfenical vapours when thrown on hot coals. 



Ochra fulva. Sy/t. nat, xii. 3. p. 193. «. 8. 



Cobalt, facie terrea. Wall f\it. 2. /. 181. ». 7. 



Brown cobalt ochre. Kirnvan miner. 2. p, 276. 



Brown earthy oxyde of cobalt. SchmeiJjer min. 2. p, 24K 



Brown cobalt ore, Thomfon chem. ^% p^ loy. 



