SCIENCE: AND INDUSTRY. 
The two volumes of Mathematics for Engineers form a comprehensive and 
valuable practical treatise on the whole subject, and will prove of service both 
as a reference work to practising engineers and as a text-book for engineering 
students. The information given in the book is clearly set out and ludidly 
explained, and the subject-matter has been so chosen, and the examples so applied 
to-practical problems as to greatly enhance the value of the work. 
Manual of the Chemical Analyses of Rocks——Henry S. Washington, Ph.D. 
3rd Edition (1919), pp. 1di. and 271. John Wiley & Sons, Inc., New York, 
This is a revised and enlarged edition (third), the first and second appearing 
in 1904 and 1910 respectively. It is obvious, therefore, that there was great 
scope for thorough revision and additions of new methods, descriptions of new 
equipment and new literature. The author thought it wiser to adhere to well- 
known and reliable methods rather than supplant them by others more recently 
proposed but not yet of proved value. In the first edition an endeavour was 
made to give the minutixe of manipulation and precautions to be observed in 
undertaking, e.g., the analysis of a silicate rock, and this idea has been further 
extended in the present edition, and more stress has been laid on the sources 
of error, both in operations and in method. To a student working alone this 
is, invaluable. Too often do we consult text-books on method, only to find that 
they all omit the minute details that we wish to find, and what other workers 
on. the same subject must meet, 
Tt is possible with this book to follow out carefully the eqeabrals of an 
ordinary silicate rock, ‘lo the expert analyst on rock work, therefore, much 
of the work may seem superfluous, but to the lone worker and to the student 
seeking to become acquainted with such work, the discussions, exact methods, 
difficulties, and the sources of error are of inestimable value. The author’s 
position on the staff of the Geophysical Laboratory of the Carnegie Institution, 
under Dr. Arthur L. Day, the Director, and the adoption of the general methods 
of the United States Geological Survey, are a sufficient guarantee of the value 
of thé methods. One hundred and eight pages (Parts I. to V.) cover the general 
methods of working, such as the apparatus, the sampling, the operations of 
decomposition, precipitation, filtration and washing, drying, ignition, and 
titration. The metric system is used, and an extremely useful section is that 
on Reagents, pages 45 to 56. We are in hearty agreement with the author’s 
recommendation for a preliminary microscopical examination, and would like 
to see this very much extended, owing to the ease, cheapness, and quickness with - 
which many microscopic qualitative analyses can be made. The use of polarized 
light, of crystallography, refractive indices, and microscopical chemical methods 
is so valuable, that the quantitative analyst might often be saved very much 
tedious work of a less accurate character. Part V. covers the main part of the 
actual determinations, and here the discussions on the source of errors are most 
valuable. The appendices include a typical analysis, factors for calculation, 
and a selected list of authoritative works, with a good index of references, 
The usual index of subjects appears to be very well done (pp. 235 to 271). .The 
book forms a valuable addition to the analytical chemist’s library. Price, lls. 6d. 
net, ‘ : 
‘Chemists’ Manual of Non-ferrous Alloys, by James R. Downie, F.C.S., pp. 168, 
with 33 illustrations. E. & F. N. Spon Ltd., 57 Haymarket, London. Price: 
10s. net. Among other positions which he has held, the author was chemist 
to the Great Cobar Mining Co., New South Wales, and the processes which he 
describes have, therefore, stood the test of actual practice. Apart from rare 
a8z 
