Cobalt. 337 



tated - r then the whole fhould be precipitated 

 by a fixed alkali, and dephlogifticated by ab- 

 ftration of the nitrous acid and calcination ; 

 if the calx be then digefted in diftilled vine- 

 gar, the cobaltic part alone will be taken up, 

 and may be precipitated by mild mineral al- 

 kali. 1 60 gr. of this precipitate denote 100 

 of cobalt in its metallic ftate. 



SPECIES III. 

 Mineralized by the Vitriolic or Arfenlcal Acids. 



Red Cobalt Ochre, Kobalt bluth, Fleurs de 

 Cobalt. 



5. This alfo is found either loofe and pure, 

 or mixed with chalk or gypfum, or indurated 

 and cryftalized in tetrahaedral cryftals, or in a 

 ftaladtitical form ; it melts eafily, and then 

 becomes blue ; it frequently invefts other co- 

 baltic ores, and is found fometimes in ftones f 

 or fand. Mr. Bergman has fhewn that the 

 arfenical acid, and not the calx of arfenic, 

 enters into this combination, for cobalt is 

 never red, but when united to an acid. 



6. To analyfe this ore, Mr. Bergman ad- 

 vifes to diflblve it in water, acidulated with 

 fome acid (fuppofe the nitrous) and then to 

 precipitate the cobaltic part with mild mi- 

 neral alkali ; the liquor will contain cubic 



Z nitre 



