554 Reviews—Tungsten Ores. 
at first inclined to regard it as an outpost of the Devonian eruptives 
of the Kristiania region, but later he has come to consider it as of 
late Precambrian date, in common with the very closely analogous 
Alné alkaline area (? Precambrian). The possibility of a Devonian 
age cannot, however, be wholly excluded. The assumption of 
selective solution in depth ‘by a Devonian essexite magma, in the 
presence of mineralizers, of the calcite of an overlying impure 
calcareous terrane of Paleozoic date, seems here not to be entirely 
precluded. Whatever be the case, one of the most remarkable and 
so far inexplicable facts, is the absence of vyiples. contact-minerals 
in the carbonatite. 
The last chapter of the memoir is devoted to a critical comparison 
with the related rock sequences of Alné, Almunge, Assynt, and other 
districts. Into this, and into Brdégger’s highly interesting discussion 
of the distribution of Scandinavian alkaline areas with regard to 
orogenic axes of folding, it is impossible to enter here. Rocks of 
the Fen region can be matched in all the above-named alkaline fields, 
but in the Alné assemblage, with its metasomatised (fenitised) 
border-zone, the most marked resemblance is provided. 
The great work is dedicated “in old friendship” to the 
investigators of Alné, the Kola Peninsula and Magnet Cove— 
Hogbom, Ramsay, and Washington. 
C. HE. TintEy. 
TunesTeN Ores. By R. H. Rastatn & W. H. Witcockson. 
Imperial Institute Monographs, pp. ix+ 81. 1920. Price 
3s. 6d. net. 
fete world depression in trade has sensibly reduced the con- 
sumption of ferro-alloys and brought about a heavy fall in the 
selling price. The interest in this and similar publications is 
necessarily somewhat limited at the present time. High-speed steel, 
in which tungsten is an essential constituent, was largely over- 
produced at the conclusion of the war period, and is still a drug in 
the market, so that economic conditions are not likely to improve 
for some time. 
The monograph has been compiled from sources indicated in the 
bibliography included in the volume. It is well compiled, and 
presents in an abbreviated form the salient features of all the 
published material on the subject, and should be useful for reference, 
particularly by those commercially interested in the metal. 
Tungsten was one of the metals controlled by Germany before the 
war, largely in consequence of an indisposition in this country to 
tackle the problem of the metallurgical treatment of the raw material ; 
and this, notwithstanding that a large proportion of the tungsten 
mineral is produced within the Empire, and the manufacture of high- 
speed steel is one of our principal industries. Stern necessity com- 
pelled us to evolve processes for production of metallic and ferro- 
tungsten, and it is hoped that the impetus given by remunerative 
