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NATIVE PLATINA. It is uncommonly heavy. Specific gravity, 15.601. 18.947, Tralles. Purified, 23.0, Thomson. Chemical Characters. • It is soluble in the nitro-muriatic acid. It is infusible, without addition, excepting in the focus of a burning- glass, or when exposed to the action of flame urged by oxygen gas. It is the least fusible of the metals. It does not amalgamate with mercury. Constituent Parts. The variety in grains, with a granulated surface, con sists of Platina, with a very minute portion of Gold, and of Palladium: the variety in flat and angular grains, con sists of Platina, alloyed with small proportions of Iron, Copper, Lead, Palladium, Iridium, Rhodium, and Os mium. Geognostic and Geographic Situations. Europe.—Platina has not hitherto been discovered, either pure, or forming a principal constituent part of any ore in Europe. The only ore in which it occurs, is the grey silver-ore of Guadalcanal in Spain. America.—It has never yet been discovered to the north of the isthmus of Panama, on the continent of North America. Platina in grains is only found in two places in the Spanish South American dominions ; in Choco, one of the provinces of the kingdom of New Granada; and near the shores of the South Sea, in the province of llarbacoas, between the 2° and 6° of north latitude. It is peculiar to an alluvial tract of GOO square leagues, where it is associated with grains of native gold, zircon, A 2 spinel,