OF COBALT, &c; 421, 



tion of nickel is unavoidably precipitated with 

 the arfenic. This appears from the melting of 

 the precipitate with borax. For when the arfe- 

 nic is diillpatcd by the aclion of the fire, the 

 glafs that remains, difplays the colour peculiar to 

 glais of nickel. But when the ball of glafs 

 cools, the colour then difappears, when it is evi- 

 dent that even in the precipitate there remains 

 '/.inc. Another and ilill more convincing proof 

 of what has been above aficrtcd, is, that the acid 

 folution, when in a large quantity, and well 

 warmed, affords together with the black powder, 

 alfo a confidcrablc portion, nearly an hundred 

 pounds of a white powder. Wlicn this takes 

 place, the green colour ofthc folution is very lit- 

 lie altered; although it could not fail to become 

 paler, if calx of nickel conflitutedtho large II pan 

 of the precipitate. The powder precipitated 

 from acid of nitre is cafily foluble with the help 

 ofh'-'ut. The folution h grey, and on the infu- 

 fion of phlogiflicatcd alkali, a fiords a powder of 

 an orange colour : a pretty ftrong indication of 

 the prciencc of a confulerable quantity of ?.inc. 

 But that the fame powder contains alfo 7/mc, 

 Pppcars from tlic colour of the folution, from the 

 iiifion of which it is fufceptible with borax ormi- 

 crocofmic fait, and from its reduction by which 

 feveral pounds of regulus of nickel arc obtained 

 feparate. 



from the green folution that remains after 

 P d 3 precipitation, 



