3o8 METALS. 96. Tungftenum. 



96.TUNGSTENUM. Greyifh orhrownifh, internally 

 fteel-white, very brittle and hard, not attrafled 

 by the magnet, fpecific gravity 17,600: fufing 

 with great difficulty, gradually changing from a 

 black to a yellow oxvde when heated, which 

 with the addition of microcofmic ialt is at laft- 

 converted into a blue gl-ifs: foluble in the nitric 

 acid into a yellow oxyde. ^ungfien Wolfram. 



eakareum^ Ponderous, lamellar, extremely brittle, yellowtni-v^ hite 

 or grey, digefted with hot nitric acid becoming yel- 

 low. 



Jernften. Cronff. mineral . 208. 



Fcrrum lapide viirefc. Wail. f\fl. z. p, 253. n, 7. 



Tungtten. ^cheele mv. Ad. Stockh. 1781. /. 89. 



Scheelium. Karfien Lejke miner i /. 575. 



Tunglten. Kirnvan mineral. 2. />. 31 5- 



Tufigftar of line. 1 homfon (htm. 4. ^, 1 f «^, 



Fc unc' rear Pevguilly in Corn^w'llt in Saxony, ard Bohemia^ iu 

 tin m n.s, and is ofren miftaken for t nilone, fomciime? 

 m ffive ' r difieniinated, fcmetimcs cryft.^Uized in double 4- 

 lidci pyraniids : it decrepitates bur doe- not melt in a white 

 heat: with borax ii forms a colour'els gl^'S, but if the borax 

 exceed a brdwnifh one: fpecific liravitj from 5,800. to 

 ^jCzS : contains, oxyde of tungften 70, lime 30. Sckeele* 



magneiia' Very pond rous, lamellar, opake, of a black ifh-brown 

 turn. colfuir ard reddifh brown ftreak, forming a greenifh 



glafs with borax. 



Molybdaenum Vy/*' na\ xii. 3. p, 123. ». 3. 



Ma^nefia cryftallim, H'all f\st. 1. p. 3^0 



Sche jiim orhr?ceum- Karfle" Leske mineral, i.p, ^j6, 



Wolfranfi K/r<wan miner. 2- p^ ^16. 



Mangineferus wolfram S hmei/s min, 2. p» 272. 



Wolfram. Thom/nn chem 4 p. 114. 



Found in Cor}j<waU., Spain. Eritnvy, Saxony, and Bohemia, in 

 tin mines mafTiive ni crvftallized in rit,ht angled 4 Tided 

 taMes, or 6 fided com r>r fled prifms ending in 4-fided fum- 

 niits: texture foliated, and eafily feparated into plates by 

 percuflion : it is infufihle by the blowpipr-, and forms a deep 

 red glafs with microcofmic fait: fpecific g'-avity from 7,006, 

 to 7i'J3;} contains oxyde of tungften 6<;, oxyde ofmanganefc 

 9.1, oxydij of iron i.j, FM:iijb,irty 



