101 Experiments for ascertaining the Existence of 



\)\- the addition of more fluid ; wherea? the precipitate ob- 

 taintd (1) by fiirther hcatiiic: the obtained fluid, was immeT 

 (diately rtdlssolyed by tlu- addition of more fluid. 



4th, Muriate otbarytcs, in a eoijcentratcd state was also 

 precipiiattd by it, as well as by arscniate of anmionia. 

 - 5tli, titrate of silver was precipitated by it of a brrvwnish 

 colour : by shaking it with a litti*^ muriate of potash, niu- 

 riata of Soda, or. iiiuriatc of ammonia, the precipitate im- 

 mediately became white.. 



(ith, Acetite of lead was precipiLated hv it white, xnd 

 immediately redissolvcd by a very small quantity of nitrous 

 acid. . 



7th, Sulphate of copper was precipitated of a bright green 

 polour. 



8th, Ammoniate of copper was precipitated in the same 

 manner, but ni greater abundance. 



9lh, Nitrate of mercury was precipitated by ihis fluid of 

 a briuht straw yellow colour; by more acid fluid (l) the 

 case was the same, and the precipitate produced arseniate 

 of ammonia. 



As all these properties of cobaltic arseniate of ammonia 

 correspond with those of the cobaltic acid of Brugnatelli, 

 those of (5) excepted, no other conclusion can be made 

 than that Erugnatelli's acid was the same combination, 

 more or less altered by the treatment; for according to his 

 assertion he obtained, by moderate heat in the sun, tVie co- 

 baltic acid solution of a red colour, whereas when evapo- 

 rated slowly by h^at it was almost colourless. The produc- 

 tion of this union, by Erugnatelli's treatment of zafl'er Vvith 

 animonia, can easily be explained : zafler contains arsenic, 

 and in all probability arseniate of cobalt. By digestion with 

 ammonia this is in part decomposed ; and as most of 

 the cobalt is separated, there arises a triple combination of 

 arsenical acid, annncniia, and more or less cobalt, which in 

 a stronf^er heat suffers a part of the ammonia and cobalt to 

 be disena'Pged, and then contains more or less free acid. 

 The difference in the property (5) of my combination and the 

 cobalcie acid of Brugnatelli can be easily explained, if it l)C 

 admitted that Erugnatelli's ammonia contained a great deal 

 of muriatic acid; which is verv possible ; for in this case the 

 bfowii arseiiiate of silver produced by the arsenical acid of 

 the combination in question must have been immediately 

 redecompo.;ed, as the inuriatic acid; in cons.equence of its 

 greater a'fHnity for the silver, united itself to produce mu- 

 riate of silver in a white form, and then gave rise to, tlx>. 

 precipitate of Brugnatelli. . 



Brugnatell^ 



