206 BROWN & HERON: GEOLOGY AND ORE DEPOSITS OF TAVOY. 



(2) " Tungsten Minerals and Deposits." Frank L. Hess, United 



States Geol. Surv., Bull. 652. 



(3) " The Modern Development of High-Speed Tool Steel." 



Sir W. G. Armstrong Whitworth & Co. J Ad., 1919. 



(4) " Tungsten, a lecture delivered before the Science Guild 



Exhibition, 30th August 1918," by Julius L. F. Vogel. 



High speed steel is made either in crucible furnaces or in the 



electric furnace. In the former practice the 

 Manufacture. . - . , , . , ,, 



correct percentages of iron and or the alloys 



are melted together, considerable skill and experience being neces- 

 sary both in this and in the forging and rolling operations on the 

 finished ingot afterwards. In the latter the process may consist 

 of melting the pure materials of the best quality, and thus using the 

 furnace as a crucible, or, alternatively, melting from ordinary 

 materials and taking advantage of the essential features of the 

 furnace for refining and removing impurities. 



Tungsten may be added to steel either in the form of the metallic 

 powder or as an alloy with iron. Before the war abortive attempts 

 had been made to establish the manufacture of tungsten in England, 

 but competition with the powerful German makers was well nigh 

 impossible, and steel makers generally obtained their supplies 

 from that source, the turnover in the business at that time having 

 reached a sum of more than £300,000 per annum. In August 

 1914 there was only a few 7 months stock of metallic tungsten in the 

 United Kingdom. Arrangements were made between the Govern- 

 ment and the Committee of high speed steel makers and by July 

 1915, the High Speed Steel Alloys Co., Ltd., commenced delivering 

 tungsten. About the same time a number of other firms also em- 

 barked on the manufacture of the metal and of the alloy ferro-tung- 

 sten. At the time of writing four firms in England produce metallic 

 tungsten, two factories make ferro-tungsten by heating pure wolfram 

 and carbon in the electric furnace, and three factories manufacture 

 the same alloy by an alumino-thermic process. 



In the chemical method the finely ground pure ore is mixed with 

 soda and heated in special furnaces to a bright red heat. The 

 product is drawn out in a molten state, allowed to cool and crushed. 

 It is then boiled with water, which dissolves the soluble tungstate 

 of soda while the oxides of iron, manganese, lime, etc., remain behind 

 and are separated by filtration. The sodium tungstate is next 

 treated with hydrochloric acid, when the insoluble tungstie acid is 



