306 SUPPOSED COBALTIC ACID. 



Jiad again heated the fluid, when it became diflblved in thd 

 liquid. In this ftate the ammoniuret of cobalt was filtered, 

 and put into a retort ; in proportion as its temperature in- 

 creafed it afliimed a violet red colour which grew deeper and 

 deeper, and at length had the appearance of the bright colour 

 The ammonia of red wine. When the greateft part of the ammonia was 

 b a heat. POrated eva P oratec * tn e mixture acquired a greenifh colour, and by. 

 repofe a fubftance of the fame colour as the (blution was pre- 

 A precipitate fell cipitated. The liquid filtered while hot and evaporated to dry- 

 fi n u1daftbrddi ed nefs ' afforded rudiments of cryftals, of which the form could 

 cryftals by eva- not be determined. White and brilliant parts were obferved, 

 poration; an( j t j ie re fl. f t } ]e ma (_ter was of a yellowith colour. Upon 



this refidue I poured water, and agitated it with a fpatula of 

 Part of the refi- platina. The leaft coloured portion was totally diflblved, and 

 iip e bywater. en comm unicated a flraw colour to the water. This fluid was 

 It was acid acid, and pollened fome of the properties announced by Cit.. 

 Brugnatelli. I ftiall prefently defcribe the experiments to 

 which I fubjected it, the refults of which properly examined, 

 but it was not prove that it is not an acid formed by the cobalt. The two 

 cobaltic acid. refidues obtained in this experiment, one of a greenifh, and 

 the other of a yellowifh colour, were proved to be not pure 

 oxide of cobalt, as Citizen Brugnatelli aflirmed, but a com- 

 bination of tiiat oxide with the arfenic acid. 

 Exp. II. The Experiment 2. Having prepared a new quantity of ammo-, 

 ammoniuret of n iuret of cobalt as in the former experiment, I fubmitted to 



cobalt was ex- , r . 



pofed to the fun ipontaneous evaporation in a fituation where the tun accele- 



tolofeits am- rated the volatilization of the ammonia. In proportion as the 



liquor evaporated a flocculent matter of a whitifh rofe colour 



Flocculent pre- f e jj down, which fenfibly increafed until the ammonia was 

 cipitate. J 



evaporated. The fluid emitted no fmell, but it had preferved 



The clear fluid a rofe colour of a confiderable beauty. I filtered it to feparate 

 filtered and eva- the precipitate, and again evaporated the liquor to drynefs. 

 nefs left a mat"- The remaining matter was diflblved in difHUed water. This 

 ter foluble in folution of.a light rofe colour was acid, and poflefled the pro- 

 waTackT an parties of the acid obtained in the former experiment, 

 the fame as in The refidue upon the filter was carefully examined, and 

 Exp. I. afecrtained to be the arfeniate of cobalt. 



Jn h th^filtre f, wa! Experiment 3. 1 took, as the author of the memoir himfelf 

 arfeniate of co- did, one kilogram of zaffre, which was pulverifed till it be- 

 balt# came an impalpable powder ; I boiled it with three litres of 



d«red zaffie wa6 diftilled water for half an hour, and filtered the liquid while 



hot. 



