Reviews—The Tin Resources of the British Empire. 381 
however, that in order to accommodate the text-figures, the length 
of the lines has had to be increased, and it is not so easy to read as 
the other books. 
To some extent the book may be regarded as complimentary to 
Harker’s Geological Map-reading, and should therefore find many 
readers who require a less rigorous and theoretical treatment of the 
subject. The reviewer feels it necessary to point out, however, 
that in these two books on the study of geological maps we have but 
the latter half of the subject, the first half beg the mapping in 
the field. To geologists in England, more or less adequately served 
by the maps of the Geological Survey, this may not appear to be of 
prime importance, but to anyone engaged in work in other countries, 
or in training people for such work, the need of an up-to-date text- 
book on geological field-mapping is very evident indeed. It is to 
be hoped that accomplished field workers such as the authors of 
these two books will consider that need and take steps to supply it. 
F. D. 
Tur Tin Resources oF THE British Empire. By N. M. PEenzmr. 
pp- 358, with plates, maps, and charts (not numbered). London : 
W. Rider & Son, Ltd. 1921. Price 15s. net. 
AS stated in a general introduction by Mr. J. 8. M. Ward, this 
volume forms one of a series dealing with the raw materials of 
industry, and unlike the rest of the series it deals only with the 
British Empire ; the reason for this is that the amount of information 
available is very great, and it is hoped that a second volume on the 
tin supplies of other countries will appear ata later date. The author 
has evidently ransacked very thoroughly the literature of tin mining, 
which, as shown by the bibliography recently published by Mr. and 
Mrs. Hess, for the Smithsonian Institution, is of vast bulk. In the 
nature of things the accounts given of the different districts vary in 
scope and value, since our knowledge of some of them is complete 
and detailed while in other cases it is vague and scrappy. This is 
due to the different points of view of those who have attempted to 
describe them. The study of a book of this kind serves to bring out 
very strongly the urgent need for a more systematic scientific 
training for mining engineers, or perhaps, to express it better, the 
need for a class of scientific mining geologists to supplement the 
work of the engineer. Only when this is brought about shall we 
attain to consistent and scientific descriptions of the mineral deposits 
of the world, especially of its more remote regions. The author has 
made good use of the material available, and has succeeded in giving 
an interesting and readable account of his subject, supplemented by 
many statistics, with maps and plans, and a bibliography of some 
forty-five pages, arranged topographically, is a valuable addition 
to the book. 
