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Mr. Charles Wood, affay-master in Jamaica, had seensome platina in that island eight or nine years before itwas imported here. He fays it was brought thither fromCarthagena ; that the Spanktrds have a way of casting itinto different kinds of toys; that these toys are verycommon in the Spanish West-lndies; that some poundsof the metal were bought at Carthagena for less than anequal weight of lilver,. and that it was formerly fold at amuch lower price. He gave some specimens of it toDr. Brownrigg, who in 1750 presented them to the RoyalSociety.

The seeming inconsistency between this account andthe foregoing, in regard to the fusibility of platina, waseasily reconciled by examining Mr. Woods specimens..Some of them were of the true platina in grains, callednative or mineral platina, which we have very goodgrounds to believe the Spaniards have never been able to;melt. But there was one of an actual cast metal, a pieceof the pummel of a sword. A part of this was sent to mefor trial; and I was afterwards favoured with a largepiece of an ingot of the fame kind of metal, by the righthonourable the earl of Macclesfield, the late worthypresident of the Royal Society. This metal was foundto melt with great ease, and was apparently not trueplatina, but a composition of it with some other metallicbodies. As the compound metal has been frequentlyconfounded with the platina itself, and called by the same.name, some considerable errors have hence arisen in regardto the properties of the platina, which will be occasionallytaken notice of in the course of our experiments. It issufficient here to have observed, that the cast metal differsmaterially from the true platina which makes the objectof the present history.

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