lyfETALS. 80. Platinum. ^45 



METALS, 



3o. PLATINUM. Of a filvery colour not tar- 

 nifhed by the air, very hard and tenacious, fono- 

 rous, exceedingly malleable and ductile, fpecific 

 gravity 23,000: not fufible in any degree of 

 heat, but detonating with nitre : folvihle only by 

 boiling it in 16 times its weight of nitro-muriatic 

 acid, and giving the folution firft a yellow and 

 then a red -brown colour; its oxyde precipitated 

 from this folution by the addition of muriate of 

 ammonia in the form of an orange powder. 



granulatum PLATINUM. 



Platina. WalLfyfi. fn'tn* 2. f, 365. n. 7. 



Platina. Wat/on Philof. TranfaS2» 46, «. 496. 



Platina. Kirnxjan miner, z. p, 103. Schmeifser mim 2. ^, 17. 



Platinum, Thom/on chem. \. p, 112. Sc 4./>, 2t. 



Found near ^ito in Peru, near Santa Fe in Neixj Granada, and 

 near the village Chocoy in mines or mixed »^'ith fand on the 

 banks of river-, always in the form of fmall fmooih compref- 

 fed grains of the colour of polifhed tin: it is always com- 

 bined with iron, fometimes amounting to an eighth part, 

 which may be readily feparatcd from it by diflblving it in 

 muriatic acid ; it is the heavicft and moft rcfradory of all 

 metal'^, and requires a very vehement degree of heat to ren- 

 der it liquid: its tenacity is fuch, that a wire 0,078 of an 

 inch in diameter is capable of fupporting a weight of 27,431 

 pounds avoirdupoife without breaking: it is ealily melted by 

 a flux of powdered glafs, borax, and charcoal : it is frequently 

 magnetic from the quantity of iron it contains. In confe- 

 quence of its great malleabiliwy, tenacity, durability, and in^* 

 folubility, it is a very precious metal. 



