228 On the Ainnionture and Acio. ...u... 



emploved ; but I eafily fucceeded in diflblving the grey oxyd 

 of this metal, commonly called %affar. This fubllance af- 

 forded me the means of eafily procuring ammoniure in abun- 

 dance, and permitted me to repeat and vary my experiments 

 different ways. 



3. I evaporated to drynefs the ammoniure obtained from 

 zaftar. The concrete refiduum I obtained, was compofed of 

 two very diftinft fubftances ; one of which had a dark red, 

 and the other a pale-yellowifli cCiIour. 



4. I poured diftilled water on this refiduum, flirrlng the 

 matter with a glafs.fpatula. The red part was entirely dif- 

 folved, and communicated to the water a beautiful rofe 

 colour. The yellowifli matter remained undidolved. 



5. The yellowifli fubflance may be obtained during the 

 evaporation of the liquid ammoniure, from which it begins 

 to be feparated at the moment when it is reduced to half its 

 bulk. The red fubftance remains diffolved in the lafl quarter 

 of the liquid *. 



6. The ammonia then takes from the zaffar, and holds in 

 folution, two very diflinft matters; one of which, foluble in 

 water, has a red colour; and the other, infoluble in the fame 

 liquid, has a yellowifli colour. The latter fubftance is the 

 pure oxyd of cobalt. I think I difcovered in the former a 

 peculiar acid, diflinft from all the other acids known. 



Of the pure Oxyd of Cobalt. 



7. The yellowifli fubflance, which is feparated by the flow- 

 evaporation of the ammoniure in the air or in the fun, may 

 be confidered as the pure oxyd of cobalt. It is infipid, in- 

 odorous, infoluble in water, and foluble in all the mineral 

 acids. The nitro-muriatic acid forms with it a yellowifli 

 folution, which is in great meafure deprived of its colour by 

 the addition of a little diflilled water. 



8. This folution may be employed for fympathetic ink, 

 like the common nitro-muriat of cobalt. Sometimes the 

 acid refufes to diffolve the whole of the oxyd, but by adding 

 a little water the folution is completed. 



* By preferving ammoniure of cobalt for fome time, even in bottles 

 well flopped, there is feparated fiom'it a yellow matter. 



\ 5. Thia 



