66 EXPERIMENTS ON PLATINA. 



of |>Iatina, and a muriatic solution of pUitina, a precipitate will be formed, 

 du -edwiih a *^°"'P"^*^ ^^ platiim and mercury united with muriatic 

 1 ule borax acid. Let this be washed, and reduced with a little borax 

 ajit c larcea . j^ ^ crucible lined with charcoal, and a metallic button will 

 be obtained. Dissolve this in nitro-muriatic acid, and it 

 will be precipitated by green sulphate of iron." 



These directions were followed, and a well melted button 

 was obtained, the specific gravity of which was about 17. 

 Platma preci- ]^j^.^ Descotils having subjected to ebullition a mixture of 

 p;ta'.ed by • 1 1 • p • 



green suli)hate green sulphate of iron and solution of platina, prepared so 



of iron. gg jQ contain but little excess of acid, a copious precipitate 



fell down ; so that this property belongs to platina itself. 



Another ditlerence remained ; it was, that the platina 

 precipitated with mercury possessed the property of being 

 liquefiable by the action of fire, which indicated a consider- 

 able difference between the button obtained and platina 

 that had not undergone the same preparation. 

 Platina fusible i^ j|,g *„,terval between this meeting and the next,. Mr. 

 wiih the addi- ... 1 .• • . l • 



tion of borax. Descotils alone treated pure platina with borax in a cruci- 

 ble lined with lampblack, and obtained a button like that 

 given by the mixed precipitate, and of similar specific gra- 

 vity. 

 The button By this experiment, which was repeated, it was proved, 



*^*cic^ackf''°" *^^* platina is capable of entering into fusion by means of 

 borax and charcoal. On dissolving part of the button, Mr. 

 Descotils obtained from it boracic acid. 

 Platina com- Platina therefore is capable of combining with the whole 

 bined with ^^ ^^^^ ^f ^he borax ; and thus alloyed it has a perfectly- 

 metallic aspect, is hard and very brittle, and takes a crys- 

 talline form internally. Mr. Descotils had already observe4 

 similar phenomena with other metal«. 

 Precipitate of The mixed precipitate urged with the most povi-erful 

 ^'erciiVnot ^^^S^ fi^^» without the addition of charcoal and borax, did 

 fusiblewithout not enter into fusion ; so that Mr. Chenevix acknowledged 

 ^arcoal and jjjg property of liquefying was not owing to the mercury, with 

 which the platina bad been precipitated, but to the char- 

 coal and borax ; and he had himself remiarked in his former 

 paper, that platina might be fused by means of borax, in a 

 crucible lined with charcoal uo doubt, as will presently be 

 seen. 



There 



