366 Elements of Mineralogf. 



by acids he means the mineral acids and the 

 acetous, then he may as well fay that bif- 

 muth is the fame fubftance as cobalt and 

 nickel, for it is aclred upon by thefe acids 

 in nearly the fame manner, but if he means 

 the long tribe of other acids, the aflertion is 

 not true, fmce the tartarous acid for inftance 

 does not act on nickel, whereas it does on 

 cobalt. 



7. 2 Iy * Becaufe though the ores of Nickel 

 become green by calcination, and thofe of 

 cobalt, blue, yet if the calcination of the nickel 

 be continued, its calx will become brown j 

 but I do not fee how this change to a reddifh 

 brown, approximates nickel to cobalt, any 

 more than the green colour does, for it is 

 equally different from the blue or chocolate 

 colour of cobalt, and it appears from Mr. 

 Bergman's experiments, that the green colour 

 arifes from a mixture of arfenic, for wheq 

 nickel is thoroughly free from it, its calces 

 are brown. 



8. 3 dly ' Becaufe nickel long expofed to the 

 air, contains a green ruft, as does cobalt 

 But this appearance would as well indicate 

 ,copper. 



9. 4 thly ' Becaufe both nickel and cobalt 

 unite with the fame metals. ]He probably 



forgo; 



