New Acid obtained from the Oxide of Cobalt. ' ^ 



a liquid rendered turbid by the precipitated yellow oxide. I decanted the liquid after the 

 precfpitate had fettled, and evaporated it to drynefs. The refidue was yellowifli, and 

 partly foluble in water, to which it communicated a yellow tinge. This folution exhibited 

 all the acid charaders of the red liquid. No. 15. 



15. In another experiment, I put one pound of the ammoniuret of cobalt .into a retort, 

 and urged the diftillation to drynefs. The fixed matter which remained on the bottom 

 of the retort was blue at the furface, but internally yellow. After fome hours tlae blue 

 colour totally difappeared, and was changed into red. • 



. 16. A remarkable difference between the refidue of the evaporation by the fun's light, 

 and that by the fire, was that the latter tranfmits the cobaltic acid nearly colourlefs ', fo that 

 the cold folution is nearly as limpid as water. I have befides remarked, that by this laft 

 procefs the acid contains little or no cobalt of ammonia. 



17. I fliall here prefent the principal characters which dlRinguifh this new adid. 

 They are 



1. Its form is concrete, and it is not volatilized by fire. 



2. In fome inftances it is red (13); in fome pale yellow (14) j and in fome colour-' 

 lefs (16). 



3. It is without fmell. 



4. It has a fliarp, and not unpleafant tafle. 



5. It ftrongly reddens the tiniSture of turnfole. 



6. It Is perfectly foluble in water. 



7. It decompofes all the fulphurets of alcali, and precipitates the fulphur. 



8. It precipitates the ammoniuret of copper of a light green, and that of zink of 

 a clear white. 



9. It precipitates the fulphuret of copper of the fame.colour as the ammoniuret of that 

 metal. 



10. It precipitates the nitrate of filver white. 



11. The nitro muriate of tin the fame. 



12. The nitrate of mercury of a light ftraw colour. 



13. The acetitc of lead white. 



14. It does not fenfibly afFedt the folutlons of gold and platina. 



15. It precipitates lime water in a white coagulum, infoluble in water, and in excefs 

 of acid. 



16. It precipitates the acetites and muriates of barytes. 



17. It is feparable by alcohol from its folution in water., 



18. When employed as a fympathetic ink, it does not give a green or blue colour, like 

 the folutlons of cobalt ; but gives a brown and afterwards a black colour to paper when 

 rather ftrongly heated, as happens with other acids. 



ig. It affords, with new made tlniSlure of galls, a yellow abundant precipitate. 



■ZO. With 



