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ing of them, to be of a very good kind. Nevertheless, asthe melting of platina, if it could be effected, would be amost important acquisition in regard to its chemical histo-ry and mechanic uses, Mr. Macquer made some furthertrials with this view. He exposed platina to the fire of aglasshouse furnace for five days and five nights, but with-out perceiving any other alterations than those already men-tioned : and indeed the glasshouse fire could not be ex-pected to subdue this refractory metal, which had alreadyresisted fires much greater than the glasshouse furnace canproduce,, and greater than its materials or vessels can sup-port.

14. For the last effort, Mr. Macquer had recourse to aforge, increasing the activity of the fire by an expedientsimilar to that which we have formerly mentioned in page7.6 of the present work. The blast from the bellows wasdivided into two pipes, which entered the furnace at twoopposite fides; and twa other great bellowfes were so dis-posed, that their blasts entered oppositely at the other twofides. Four ounces of platina, in a Hessian crucible, beingplaced in the middle of the furnace, the fire was excitedby the bellowfes to such a degree, that in less than anhour and a quarter, all the internal part of the furnacemelted and run towards the bottom, forming in the lowerpart masses of glass, which, stopping up the orifices of theblast-pipes, made it necessary to discontinue the ex-periment: the crucible, which was all vitrefied, beingtaken out some time after, appeared still of so dazzling a-whiteness that the eye could not support its lustre: yetnotwithstanding this extreme fire which the platina hadsuffered, it was no more melted than in the foregoing ex-periments; except that in the vitrifications, which sur-rounded the crucible, there were found some grains, of asilver whiteness, perfectly round, which appeared to have

had.