VII. History of PLAT IN A.

I N the beginning of the year 1749, there was broughtinto England, from Jamaica, a quantity of a whitemetallic substance in grains, scarcely known before toEurope, said to be the produce of the Spanish West-Indies, and there called Platina, Platina di Pinto , or delPinto , and Juan bianco.

The name Platina seems to be a diminutive of flatd,silver, and consequently to express the most obvious ap-pearance of this body, that of a silver-coloured metal insmall grains. From its being called platina of Ptnto, itmay be supposed that Pinto is the name of some particularspot or district w hich affords it: I have not met withthis name in any accounts I have seen of Spanish America,but Mr. Cronstedt, in av effay for a new mineral System,lately published in Sweden, speaking of platina in thecourse of his system, calls the place k is brought fromRio di Pinto. Its other appellation, Juan bhmco, aroseperhaps from some frauds which had been practised withit, from the difficulty of separating the gold naturallyintermingled with it, or from its refractoriness in thehands of the workman ; for as in our own country adusky coloured mock-ore, that is, a mineral which hasthe appearance of a metallic ore, but does not in theusual ways of trial yield any metal, is commonly calledblack-jack the Spaniards may in like manner have giventhe name whits jack, white rogue, white mock metal, to thissingular metallic body, which though of the true metallicaspect and weight, and in some degree malleable, hadeluded all their attempts for smelting or running it down.

M m m Mr.