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amounts to about one third of the tin or upwards, themalleability, which both metals separately possess, is de-stroyed by their combination with one another. The dif-ference in the colours of these compositions was not soconspicuous on the touchstone, as when the fractures ofthe ingots were examined; although, on close inspection,the marks on the stone also appeared all of a darker colour*than those of pure tin, and the more so as the proportionof platina prevailed in the mixt. Kept in a close room,in pill-boxes, they all tarnistied in the fracture to a yel-lowish hue; but pieces which were ground and polisliedhave in ten years suffered little change, except only themixture of equal parts of platina and tin, which is grownconsiderably dull and yellow.

It is observable, that though tin is a metal very readilydestructible by sire, yet in most of the foregoing fusionsthere was scarcely any loss of weight. This may be at-tributed in part to the admixture of the platina preventingthe scorisication of the tin; and in part to the flux madeuse of, and the celerity and short continuance of the heat.No. 2 and 7, where the heat was slowly raised and longcontinued, were the only ones in which the loss was at allconsiderable.

IV. Flat ma ’with Lead.

1. Equal parts of platina and lead were injected into amixture of black slux and common salt previously meltedtogether, and the sire raised hastily by bellows. A muchstronger heat was requisite than for the fusion of platinawith an equal quantity of tin, and the loss was considerablygreater, amounting to about one sixty-fourth part ot themetallic mixture. The metal yielded, difficultly to thefile, broke from a moderate blow, and appeared, on thefracture, of a close texture, an uneven surface, and roughjagged edges. The colour was very dark, with a faintpurplish cast.