it,^2 On the Ammonliire and Acid of Colalt. 



cafe with the acid of cobak. 3d, The arfenic does not, like 

 the cobaltic acid, decompofe the mnriat and the acetite of ba- 

 rytes. 4th, The arfenic acid is fohible in alcohol, which 

 precipitates the cobaltic acid under a concrete form. 



It remained to be afcertained whether the acid extracted 

 from zafFar exifted already formed in that oxyd, or whether 

 it was produced by the aftion of the ammonia. 



As the acid of cobalt readily diflTolves in water, I boiled fix 

 pounds of zaffar in eight pounds of water for a quarter of an 

 hour, and filtered the liquor while warm. What paflled was 

 tranfparent and colon rlefs, but manifefted a fenfible tafte. I 

 evaporated the liquid, takino- care to cover the veffel with a 

 piece of filk. When reduced to one-half it became turbid, 

 without the fub fiance which was feparated appearing fenfibly 

 coloured. I continued the evaporation till a third only of 

 the liquor remained. When I removed it from the fire there 

 was depofited a very white matter, which, on coming into 

 contaft with the air, affumed a beautiful rofe colour. I fe- 

 parated this matter, and collected it on the filter. 



The liquor which pafied had a bright-yellow colour, and 

 was perfeftly tranfparent. It manifefl;ed in a decided manner 

 an acid tafl:e ; reddened tincture of turnfol ; fpeedily decom- 

 pofed lime-water, falls of barytes, and thofe of filver ; was 

 precipitated with alcohol, &c. In a word, it exhibited all 

 theproperties of the cobaltic acid obtained by the procefles 

 before mentioned. 



The red depofit which remained on the filter was infipid, 

 and gave to the muriatic acid a very beautiful green colour. 

 It was the pure oxyd of cobalt. This oxyd diffolved in a 

 large quantity in its acid, and was precipitated from it in 

 proportion as the latter was concentrated. The acid which 

 the ammonia had feparated from the zafi'ar was found then 

 entirely formed in that fubftance. It fi:i}l remains to be 

 determined, in a pofitive manner, what is its radical. In the 

 mean time I thought it my duty to retain its name of the 

 cobaltic acid. 



X. Ob. 



