rOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 99 



ceding the above date, by Mr. Charles Wood, a skilful and inquisitive metallur- 

 gist, who met with it in Jamaica, whither it had been brought from Carthagena 

 in New Spain. And the same gentleman had gi'atified Dr. B.'s curiosity, by 

 making further inquiries concerning this body. It is found in considerable quan- 

 tities in the Spanish West Indies, and is there known by the name of platina di 

 Pinto. The Spaniards probably call it platina, from the resemblance in colour 

 that it bears to silver. It is bright and shining, and of a uniform texture ; it 

 takes a fine polish, and is not subject to tarnish or rust ; it is extremely hard and 

 compact ; but like Bath-metal, or cast iron, brittle, and cannot be extended 

 under the hammer. * ./ 



The Spaniards do not dig it in the form of ore, but find it in dust, or small 

 grains, as were herewith presented to the r.s. Whether they gather it in a 

 pretty pure state, as brought to us, or wash it, like gold-dust, from among sand, 

 and other lighter substances, was to him unknown : however, it is seldom col- 

 lected perfectly pure ; since, among several parcels of it that he had seen, he 

 constantly observed a large mixture of a shining black sand, such as is found on 

 the shores of Virginia and Jamaica, which is a rich iron ore, and answers to the 

 magnet. It has also usually mixed with it some few shining particles of a golden 

 colour, which seem to be a substance of a different nature. 



It is very probable that there is great plenty of this semi-metal in the Spanish 

 West Indies ; since trinkets made of it are there very common. A gentleman 

 of Jamaica bought 5 lb. of it at Carthagena for less than its vreight of silver ; and 

 it was formerly sold for a much lower price. 



When exposed by itself to the fire, either in grains, or in larger pieces, it is 

 of extreme difficult fusion; and has been kept for 2 hours in an air-furnace, in 

 a heat that would run down cast iron in 15 minutes: which great heat it endured 

 without being melted or wasted ; neither could it be brought to fuse in this heat, 

 by adding to it borax, and other saline fluxes. But the Spaniards have a way of 

 melting it down, either alone, or by means of some flux ; and cast it into sword- 

 hilts, buckles, snufi'-boxes, and Other utensils. 



When exposed to a proper degree of fire, with lead, silver, gold, copper, or 

 tin, it readily melts, and incorporates with these metals ; rendering the mixture, 

 like itself, extremely hard and brittle. 



Having been melted in an assay-furnace, on a test with lead, and with it ex- 

 posed to a great fire for 3 hours, till all the lead was wrought off, the platina was 

 afterwards found remaining at the bottom of the test, without having suffered 

 any alteration or diminution by this operation. 



A piece of platina was put into strong and pure aqua fortis, and with it placed 



• Not in its native or crude state j but when properly purified, it may be extended under the hammer. 



o a 



