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ladle, and exposed to a moderate fire. The mercury eva-porated freely, and left the platina behind, in form of a darkcoloured powder intermingled with iome small brightshining particles. It may be presumed that the platina, bythis dissolution in quicksilver, is purified from great partof its iron, a metal which quicksilver has little dispositionto unite with.

III. Separation os Arsenic from platina.

Pieces of platina, which had been melted with arsenic,were urged with a very strong fire in an open crucible.Arsenical fumes, distinguishable by their garlic smell, arosein abundance for some time : at length the. fumes entirelyceased, and the platina remained in a spongy mass. Onthis mass I injected a fresh quantity of arsenic, so as tobring it into fusion, and having then hastily excited thefire till the fumes ceased, found the matter again spongy,and nearly of the same weight as after the first operation.This was repeated three or four times,with the same event.It did not appear that the arsenic carried off with it anypart of the platina, as it does of all the other metals, golditself not excepted : but a portion of the arsenic seemed tobe retained by the platina even in strong fires. Thoughthe mass was pretty compact when so far satiated with thearsenic as to be in some measure fusible, it always becamespongy when so much of the arsenic had been dissipated asto leave the platina unfusible. All these masses were spe-cifically lighter than the platina at first,, the gravity of theheaviest of them being only about 16,80.0..

IV. Separation osRegnlus of antimony from platina.

A mixture of platina and regulus of antimony wasmelted in a strong fire, in a shallow wide crucible, and thenose of a bellows directed obliquely upon the surface of the

fluid.