| Show TUNGSTEN IN it is only within the ladew years that tungsten and its various jj salts salt sand and alloys have been brough tinto general use says the journal of the royal society of arts ad its employment in the man manufacture u facture of filaments for incandescent lamps has of course made this particular use of it very familiar but its chief avalue yV value alue lies in the fact that when sit la Is added to steel the latter acquires the property of self 1 hardening dening and requires require 3 no tempering anu this hardness it re bains at red heat this renders lt it extremely valuable for high speed cutting tools the salts of tungsten are also used in tain industrial pro processes esses such as dyeing fireproofing fire proofing the differential analysis of tanning mate trials rials and the manufacture of bronze bonze colors until comparative ly recently the chief source of supply was the united states but some five yea years rs ago the first serious attempt was made to develop th the e wolfram rn deposits of the indian empire and lower burma now heads the list as the worlds greatest producer the total production of the world la 19 about tons per annum of concentrates carrying from 60 to 70 per cent of trioxide of this burma produces one quarter bradstreets |
