[ 126 ] [fcookVl, 



CHAP. XXL 



T U N G S T E I N. 



T&e Ore of Tungjtein confounded <witb that of Tin. Where found.- 

 Mode of reducing it to the reguline or metallic State. 



TUNGSTEIN or wolfram is a particular 

 metal, the ore of which has frequently been 

 confounded with that of tin. The fpecific gravity 

 of this ore is to water as fix to one ; in its form of 

 cryftallization it refembles the garnet, and vanes in 

 colour, from a pearl white to yellow and reddifh ; it 

 is found in feveral pa 1 rts of Saxony and Bohemia. The 

 mineral called wolfram, which is frequent in the 

 mines of Cornwall, is likewife an ore of this metal; 

 in all thefe ores the metal is oxydated ; and in fome 

 of them it appears to be oxygenated to the ftate of 

 an acid, being combined with lime into a true tungftat 

 of lime*. 



The calx of this metal cannot be obtained free from 

 the bodies with which it is united, without a particular 

 procefs, which confifts in the alternate application of 

 volatile alkali and marine acid, and the fubfequent 

 addition of die nitrous acid, as long as red fumes are 

 produced. This calx or imperfect acid has the co- 

 lour of brimftone, and 7s fcarceJy foluble in water. By 

 being fubmitted in a crucible with charcoal, to a ftrong 

 heat, a regulus of tungftein, called tungftenite by late 

 mineralogifts, may be obtained, which is a brown mafs, 

 confiding of a congeries of metallic globules internally of 

 a fteel grey, and which again becomes yellow by calcina- 



* Lavciiier's Chemiftry. 



* tion. 



