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From the effect of a long continuance of strong st re onmixtures of platina and lead in the preceding article, I wasinduced to submit to the fame treatment mixtures of itwith bismuth, a metal which promised to be easier sepa-rated than lead, as being itself much more easily dissipatedby fire.

Some of the cupelled plates of the foregoing operationswere kept for six hours, on four cupels under a muffle, inas strong a heat as could be raised in a good assay furnace.Of one of the plates a part had melted, and spread in finesilver-like leaves over the edge of the cupel : of all of themthe thin edges bore to be hammered pretty well, and bentconsiderably before they cracked : the cupels were stainedof a pale orange yellow. The plates being then urged forsix hours longer on fresh cupels, in the wind furnace be-fore mentioned, they all proved of a bright silver colour,and hammered well in the thinner parts, but still conti-nued brittle in the thick ones: the cupels were veryslightly tingecs.

From the experiments related in this section it appears,that platina perfectly resists the destructive power of leadand bismuth, which, with the concurrent action of fire andair, reduce all the other known metallic bodies, exceptgold and silver, into a. calx or scoria : that it resists anti-mony, by which silver as well as the base metals are scori-fied, and which has always been esteemed the severest testof gold : that it is not sensibly volatilized by arsenic, whichin strong hasty sires carries off a portion of gold itself: thatin degrees of heat considerably stronger and of longer con-tinuance than have hitherto been employed for these kindsof operations, the platina preserves a part of those de-structible metallic bodies themselves, retaining so muchof them as to be rendered brittle ; but that by furthercontinuance of vehement fire, those bodies, at least lead

and.