REMAKING AFTER THE SOLUTION OF PLAT1NA. Hj 



it muft have been contained in the fubftance of the grains of 

 platina. Though it has fomevvhat the appearance of plum- refembh'ng 

 bago, it may eafily be diftinguilhed by its fuperior weight. h e ^ e ^°' 

 By weighing it in a phial with water, I found its fpecific gra- 

 vity almoft J 0.7. 



Before I defcribe the method of feparating the two metals of ^ e c t °™ b ^ wUh 

 which itconfifts, it may be worth while to mention the effe&s CllaU p " ortion 

 of it, when combined with different metals in its entire ftate. renders lead, 



... . . , . . , *,. ■. i .- bifmuth, zinc. 



It readily unites with lead; but, even with ten times its own and tinj diffi _ 



weight, the compound has not, when melted, much fluidity, cultly fufible 

 Upon diflolving the lead in nitrous acid, the black powder was 

 obtained, with little apparent alteration, not having been en- 

 tirely broken down, but confiding chiefly of the fame fcaly 

 particles as at firft. With bifmuth, zinc, and tin, the effecls 

 were nearly fimilar; but, by fuflon with copper in a very 

 ftrong heat, a more perfect union was produced. On at- 

 tempting to diflblve the compound by nitro-muriatic acid, 



me of the powder was taken up with the copper, forming with copper; 

 a very dark foiutioh. 



The undifTolved portion confifred partly of the fubftance in 

 its original form of (bales, and partly of a blacker powder, the 

 particles of which were too fmall to be vifible, and which had 

 probably been completely combined with the copper. This filver or gold j 

 fubftance may be eafily united, by fufion, with filver or gold ; ^^ hk by 

 and it is particularly deferring of attention, that it cannot be 

 feparated from thefe metals, by the ufual procefs of refining. 

 It remains combined with either of them, after cupellation with 

 lead ; and with the gold, after quartation with filver. The 

 alloys retain confiderable ductility ; and the colour of that with 

 gold, is not materially different from pure gold. 



I fhall now proceed to defcribe the analyfis of the black Analyfis of the 

 powder, and the properties of the two metals which enter into bl j^k powder; 

 its compofition. The method which I ufed for diflolving it, two metals, 

 was fimilar to that employed by M. Vauquelin, the alternate 

 action of cauftic alkali, and of an acid. I put a quantity of the Fufion with 

 powder into a crucible of filver, with a large proportion of 

 pure dry foda, and kept it in a red heat for fome time. The Solution In wa- 

 alkali being then diflblved in water, had acquired a deep' ei '- deeponmge » 



° n r leaving a pow- 



orange, or brownifli -yellow colour, but much of the powder der; 



remained undiffolved. This powder, digefted in marine acid, which was partly 



gave a dark blue folution, which afterwards became of a d ! ffoIv ^'nm- 

 P • natic acid* 



dulky 



