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and bismuth, may be wholly or almost wholly dissipated,so as to leave the platina in a mass, as malleable as thefinest grains were separately, and perhaps more so, in vir-tue of their being purified in the operation from theirirony or other foreign matters, as gold and silver are bythe like means from all the base metals.

How far this dissipation of lead or bismuth may bepracticable in the large way, or on masses of considerablethickness, cannot be absolutely determined from the ex-periments hitherto made, for as yet, with me at least, theprocess has succeeded only on thin pieces of the metal.Mr. Macquer seems to make no doubt that platina mayon this foundation be rendered manageable by the work-man in large, so as “ to furnish us with burning concaves,specula for telescopes, an infinity of vessels and utensils forchemical and culinary uses, and almost all the works ofthe locksmith.” He observes that platina would for thesepurposes be an excellent material, " as its vivid and brilli-ant polish is never tarnished by any kind of rust, and as itnot only resists the action of air, water, fire, acids, and thevoracious metals, as well as the purest gold does, but joinsto these admirable qualities a property still more precious,which is wanting to gold, viz. the force and hardness ofiron.” In my experiments, the cupelled plates, both withlead and bismuth, were considerably harder than fine goldor silver, but softer than iron : the hardness here attributedto them appears to be inferred from the experiment onprecipitate of platina related in page 505.

SECT.