OF COBALT, &c. 



adheres to it, and is the caufe of its acquiring a 

 green colour from borax and microcofmic fait. It 

 communicates a yellow colour to the acids in 

 \vhich it is diflblved ; and without the portion of 

 it employed be conliderable, no redneG appears 

 in the fulution. 



5 v. Precipitate of Mauganefe. 



THE exiflcnce ofmangtiUcfe was but very late- 

 ly difcovered. Of tins I have cUewherc given u 

 particular account. Krm a folution of an hundred 

 pounds of this metal, aerated mineral alkali pre- 

 cipitates 185 pounds, cauflic alkali 168, and 

 phlogifticutcd alkali 350. The firll of thefe pre- 

 cipitates is whitifh, with ycllowifli brown parti- 

 cles intermixed. The fccond is of a dark colour. 

 The tliird Is at iiril green, but changes to yellow 

 towards the end of the precipitation ; inconfe- 

 qucncc of which the dried powder, being a mix- 

 ture of green and yellow, has a grecnifh appear- 

 ance. But it is always to be obfcrvecl, that 

 while regulus of inangancfe is diilblving, a imnvn 

 powder is feparateil,; which \ obtained in tlic 

 proportion of fevcn pounds to the hundred, 

 weight of numganefc clillblvcd in vitriolic acid. 

 This powder is micaceous; it produces a violent 

 detonation with hot fufcd nitre; the fmnll por- 

 tion of iron which it contains, enables it to com- 

 municate an orange colour to acids; but it is in- 



