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poured out, run cleast from the crucible, and weighed justtwo ounces and a half, so that the platina was here kept infusion by one fourth its quantity of zinc. This mixturewas put into the fame crucible, with the fame borax : itstill deflagrated, melted, and on being poured into an ironingot-mould,which had been newly smoked over the flameof a torch but not heated, the fluid metal was thrownabout with violence in small drops : this probably hap-pened, not from any particular qualities of the metal, butfrom some moisture in the mould.

Compositions of platina with different proportions ofzinc differed little in appearance from zinc itself; exceptthat where the quantity of platina was large, they were ofa closer texture and duller hue, with rather more of a blu-ish cast. Kept for ten years in a dry room, they do notleem to have tarnished or changed their colour. Theywere much harder to the file than zinc itself, and sell inpieces under the hammer ; without at all stretching, aspure zinc does in a considerable degree. One twentiethof platina destroyed the malleability of zinc, and one fourthof zinc destroyed the malleability of platina : within thiscompass, we have no degree of ductility to expect fromany mixture of the two.

VII. Platina with Regulus of Antimony.

Equal parts of platina and regulus of antimony weredropt into a fluid mixture of black flux and common salt,and the fire strongly excited by the bellows. They meltedperfectly together, and run freely into the mould. Thecompound looked of a much duller colour than the regu-lars at first, and, when broken, shewed a close and uniform,though uneven surface : it proved considerably harder tothe file, but not remarkably more or less brittle under thehammer.

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