from the Desert of Atacama in Peru. 227 



28*77 grains of it were exposed to the action of nitro-muriatic 

 acid, and were completely dissolved by that menstruum. The 

 solution, after being moderately diluted with cold water, was gra- 

 dually neutralized by the bi-carbonate of potash, with the view 

 of precipitating the iron, and retaining the cobalt and nickel in 

 solution by the excess of carbonic acid. 



The hydrated red oxide of iron, after being carefully washed, 

 dissolved without residue in oxalic acid, and therefore did not 

 contain any nickel or cobalt. The peroxide of iron was then 

 thrown down by ammonia, collected, and heated to redness. Its 

 weight was 38'39 grains, equivalent according to the atomic tables 

 of Dr THOMSON, to 26'87 grains, or 93'40 per cent of metallic 

 iron. 



The solution from which the iron had been removed by the 

 bi-carbonate of potash, had a green tint ; and on expelling the 

 free carbonic acid by heat, the hydrous carbonate of nickel sub- 

 sided. The precipitation was completed by the aid of pure pot- 

 ash. The precipitate, after being washed, was treated by a solu- 

 tion of oxalic acid, and was thus converted into the granular oxa- 

 late of nickel. The acidulous solution of oxalic acid did not 

 strike a blue colour with the ferrocyanate of potash, nor yield a 

 precipitate when neutralized with ammonia, and consequently 

 was free from iron. 



The oxalate of nickel was dissolved in pure ammonia ; and 

 after it had separated from the liquid by the gradual dissipation 

 of the alkali, the remaining liquid had a pale pink colour, and 

 on evaporation yielded a minute residue, which, after being heat- 

 ed to redness, weighed 0'22 of a grain, and formed a blue bead 

 when fused with borax. Regarding it as the peroxide of cobalt, 

 and as composed of 26 parts of metal and 12 parts of oxygen, 

 the quantity obtained by analysis indicates 0*154 of a grain, or 

 0'535 per cent, of metallic cobalt. 



The oxalate of nickel was decomposed by heat, and yielded 



F f2 



