Reviews—Tungsten Ores. 555 
war conditions will prevent the industry reverting to Germany, 
although it may be noted that at the present time that country is 
the only persistent buyer of tungsten ore. The value of the raw 
material was 25s. to 35s. per unit in 1914, but these figures were 
increased in this country during the war, and more particularly in 
the United States. So severe, however, is the slump that ore is 
now worth only 12s. 6d. per unit cif. U.K. ports, and unless an 
appreciable rise takes place in the selling price, the cost of production 
will require severe readjustment. 
In dealing with the genesis of tungsten ore, it is noted that they 
are usually found with tin in granite veins and pegmatites, and much 
controversy has arisen with regard to the relative temperature of 
formation of the minerals of these two metals, with a view to 
determine their occurrence in depth, in Burma and the Malay 
Peninsula. The authors remark that further information about 
other occurrences is desirable. 
The sporadic occurrence of the mineral prevents any calculations 
of reserves being made, but its association with granitic rocks in 
many widely distant areas should guarantee a constantly imcreasing 
output, to meet the greater demands which will follow a general 
trade resumption, by reason of the valuable properties tungsten 
confers alone, and associated with other metals, on steel. 
The remarks on the utilization of tungsten are useful. Whilst 
Mushet was undoubtedly the first to produce a special tool steel 
containing tungsten, the term “high-speed steel’ was originally 
applied to a tungsten steel containing molybdenum, first exhibited in 
1900. Subsequently British manufacturers made an equally good 
steel without molybdenum, but in recent years it, and other metals, 
have been introduced, and changes are made from time to time in 
the composition and heat treatment of the material in order to obtain 
the best results. 
The use of tungsten for electric lamps is mentioned, and it may be 
remarked that the production of the wire was impossible, until a 
process was evolved whereby the ingot was heated in hydrogen to 
a point below annealing temperature, and subjected to repeated 
swaging, the effect of which was to elongate the equiaxial grains 
into fibres of metallic tungsten. In this way tungsten wire was made 
ductile by a method which usually produced brittleness in other 
metals. A small quantity of thorium nitrate, added to the tungsten 
oxide before reduction controls the grain growth, and by coating 
tungsten with a precious metal or alloy, the product has been found 
superior to platinum or its alloys in many ways. 
The memoir is divided into three chapters, of which the first deals 
with the occurrence, characters, and uses of the ores, and the second 
and third with the British and Foreign sources of supply. 
The description of occurrences of tungsten ores in the British 
Empire is good, although possibly greater prominence might have 
been given to the Burma deposits, having regard to the fact that 
