OF COBALT, &c. 423 



od alkali precipitates from the fame folution a 

 powder of the fame colour, but of a different cha- 

 raftcr in other rclpech, and in weight 142 pounds. 

 The production of the firR precipitate is accom- 

 panied with eflervefccnco ; the fecond Aibiides 

 without any emotion in the li(|uor t the third is 

 ubfolutely infoluble in acids. The fame tiling is 

 it rue of the precipitates of nickel, prepared with 

 the fame alkali. 



Nitrous acid faturated with an hundred weight 

 of rcgulus of cobalt, upon the addition of an c- 

 <]ual quantity of zinc, precipitated only a fmali 

 portion of (limy matter. I rendered the folution 

 thicker by boiling, but in vain; for except the 

 flimy matter, a part of which covered the plates 

 of y.inc, no other precipitate was produced. The 

 zinc itfelf, as 1 found, upon waihing and drying 

 it again, had frittered no lofs of weight. Water 

 poured upon the rcfiduc was very Toon tinged 

 with a red colour ; and, on the admixture of ac- 

 rated fixed alkali, afforded 135 pounds of a pre- 

 cipitate, unufually red. The ilimy matter when 

 fepnrated, wafiicd and dried, had a grecncolour, 

 which the a^ion of lire rendered blackilh, and 

 was fubjcft to the attraction of the magnet ; 

 whence it appears to have b?en calx of iron fe- 

 paratcd in 'the boiling, in the fame manner as 

 ochre is commonly fcparatcd from a folution ot 

 iron. This feruginous matter is for the mod- 

 part, void of arfcnic ; a fmall portion of cobalt 

 I) d -| . adhere^ 



