from the Pyrites. 291 



calcaneus earth, as vitriol- oil reduces the white me- 

 tals to, and wherein not fo much as a faline or vitriol 

 form can be exhibited •, nor in fuch' a colour, as 

 that in a quite furprifing manner appearing in the 

 unparallelled green and blue vitriols, never pro- 

 ducible from other metals by their appropri- 

 ated falts, except from bifmuth-ore ; where, 

 under peculiar encheirefes, or treatments, not only 

 a genuine vitriol-green appeared, as M. Linck and 

 J myfelf found, but alio from my own fmall expe- 

 rience, a genuine purple and blood-red : nor has 

 hitherto at lead, what Caneparius, after the an- 

 cients, relates, been fufficiently verified ; namely, 

 that each metal does in Jolution Jhew its own peculiar 

 colour ; efpecially if we are willing to afcribe the 

 blue to the filver, and can prove this from a blue 

 fiiver folution ; though it be certain, this blue co- 

 lour ever proceeds from fome fmall fhare of copper 

 in the filver •, it never appearing, if we only run 

 this filver ore over again to its metallic body, and 

 refine it with nitre in the crucible, efpecially in the 

 cafe of a coppery lead, and a cold fulmination in 

 the ad of cupellation. 



I know not, whether to call it an unguarded, or 

 rather an undiftincl: way of exprefiing himfelf, when 

 he pretends, an iron-vitriol is diftinguifhable by a 

 brown- red ; a copper '-vitriol^ by a green •, as here 

 he muft certainly mean, not the vitriols themfelves, 

 but the vitriol-waters -, and then indeed an iron- 

 vitriol- lie appears of a brown-red 5 and yet when 

 pure, ic is at fir ft of a beautiful green > and a cop* 

 per -vitriol-lie feems, but yet is not, really green., 

 But, as iron and copper appropriate to themfelves 

 the fulphur-acid, to the exclufion of the other me- 

 tals, fo they not only quit thefe their native fol- 

 vents, but alfo fubmit to others \ a very remark- 

 able circumftance 3 and defer ving our clofeft attei> 



U 2 tiou, 



