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6. The foregoing experiment was many times repeated;in different kinds of crucibles, both German and English;with fires of charcoal, of common fea-coal, and of fea-coalcoaked or charred. In the most intense sires I was ableto excite, such as neither the best of the crucibles, nor thefurnace, could long support, the platina did not appear tomelt, or soften, or alter its figure. I sometimes indeedobtained a few globular drops, of the size of small shot,of smooth surfaces, which broke easily on the anvil, andlooked internally grey: these drops had evidently beenmelted, but it is probable that they were not pure platina,and that the fusion was owing to an admixture of the ferru-gineous part of the mineral, or of the golden grains: forwhen the purer picked grains of platina were employed,-there was never any appearance of melted particles; andthose parcels of the mineral which had once yielded somemelted drops, could never be made to afford more, thoughurged with fires at least as vehement as the first time.The cohesion of the grains of platina seemed to begin ina moderately strong red heat, and to become firmer andfirmer as the fire was made more violent, though I neverfound them cohere so much as to resist a small blow of ahammer. The colour, after strong fire, was almost alwaysbright and white, except on the surface of the mass, whichwas often changed to a dark brownish, with sometimes afaint yellowish tinge: in one experiment, the metal, whenviolently heated, having been quenched in cold water, thegrains which composed the internal part of the lump ac-quired a violet or purple colour.

7. I picked out some of the larger and brighter particlesof platina, to the weight of about fifty grains, and spreadthem on the bottom of a smooth crucible: the vessel be-ing covered, and kept in a vehement fire, as in the aboveexperiments, for about an hour, the platina cohered but

slightly,