494 
A series of practical tests in various sections shows 
that it is easy to trace at once the information sought ; 
and to this end a system has been adopted in which 
rigidity has been tempered very wisely. There are 
chapters in Part II. which one might have expected 
to be placed near others in Part I.; for example, 
thermochemistry is separated from thermodynamics in 
this way, and cryoscopy from vapour pressures ; but 
some change in the sequence of sections may doubtless 
be made hereafter, and in the meanwhile there is no 
obstacle to utility. The printing is clear; and with 
the tabulated data the compilers give sufficient indica- 
tion of the experimental method used, mention any 
general formule found applicable by the author, and 
state the conditions quite unambiguously. The use 
of graphs instead of tables in dealing with subjects 
such, for example, as absorption-spectra, equilibrium 
mixtures of metals, or the ignition of gaseous mixtures, 
is well carried out. In chapters treating of organic 
compounds Richter’s classification is used ; and it is 
clear that the vexed question as to the organic or 
inorganic nature of calcium carbide would present no 
difficulty to the editor, for he provides the useful 
category of ‘“‘ Corps mixtes.’’ This name, however, 
although no doubt correct in French, should certainly 
not be rendered in English as ‘‘ mixtures.” The mis- 
spellings of English authors’ names are probably not 
more frequent than can be matched in English references 
to foreign literature. 
Dr. Marie prints his regrets that this volume, covering 
1913-1916, is only now issued ; but, as in the case of 
Dr. Johnson’s dog, the marvel is, not that it is done 
so well, but that it is done at all; for the difficulties 
during and just after the War must have been very 
great. That these difficulties have been passed, so 
that we have Volume IV., are informed of an accelerated 
issue of Volume V. (1917-1921), and may look for a 
regular progression thereafter, is a real achievement 
‘in advancing research. iM 


Our Bookshelf. 
Modern Tunneling. By David W. Brunton and John 
A. Davis. (New Chapters on Railroad Tunneling, 
by J. Vipond Davies.) Second edition, revised and 
enlarged. Pp. x+612. (New York: i Wiley and 
Sons, Inc. ; London: Chapman and Hall, Ltd., 1922.) 
335. net. 
THE first edition of this work was published in 1914, 
and its contents were limited to mine and water-supply 
tunnels. The present edition has been revised and 
enlarged by Mr. John Vipond Davies, and contains new 
matter dealing with large-sized tunnels. The early 
part of the volume contains a very good discussion on 
the plant required: in the construction of tunnels, and 
includes such subjects as the factors influencing the 
choice of prime movers, types of air compressors, surface 
NO. 2789, VOL. 111] 
NATURE 


[APRIL 14, 1923 

plant generally, and methods of ventilation. This is 
followed by critical descriptions of the various under- 
ground appliances, such as rock-drilling machines, the 
methods of blasting, haulage, etc. The great develop- 
ment of tunnels during the last fifty years has been due 
to the application of high explosives and rock-drills, 
and this part of the subject receives adequate treatment. 
Details of the cost of a large number of tunnels are 
included, together with the speeds attained in driving 
them. There are two comprehensive bibliographies, and 
these may be regarded as an essential feature in a book 
on this subject and of moderate dimensions. The 
matter is presented in a very readable manner, and the 
volume will be of service not only to the engineer 
engaged in practice but also to the student of civil 
engineering. 
La Force motrice électrique dans Industrie. Par Eugéne 
Marec. Pp. viiit+613. (Paris: Gauthier-Villars et 
Cie., 1922.) 55 francs. 
M. Marec’s book is written for those who, having a 
sound theoretical knowledge, are more concerned with 
the choosing and installing of electrical machines than 
with the manufacture of them. The operation of the 
finished machine is discussed mainly by describing its 
characteristic curves. The engineer is thus enabled to 
judge which type of machine will prove the most useful 
for the particular purpose he has in view. The various 
methods of installing electrical machinery in a work- 
shop are fully described. The book will be of use to the 
English engineer, as it will show him the best modern 
French practice, and it will be helpful for him to com- 
pare it with his own. The various French methods of 
charging for alternating-current power will interest him. 
One method is. to charge the consumer for the watt- 
hours he has consumed. In addition a further charge 
is made for the magnetising hours, this further charge 
only being zero when the consumer uses apparatus the 
power factor of which is unity. The latest French rules 
for standardising apparatus and methods in electrical 
engineering are given. The comparison of them with 
the American and English rules is instructive. 
Orographical, Regional, Economic Atlas. Edited by 
T. Franklin. Part 4: Africa. Pp. 32. (Edin- 
burgh: W. and A. K. Johnston, Ltd.; London: 
Macmillan and Co., Ltd., n.d.) 1s. 6d. net. 
Tuts collection of forty-seven diagrams and maps 
of Africa and parts of Africa is wonderfully good value. 
It includes a coloured orographical map of the whole 
of Africa and sectional maps of the same on enlarged 
scales. A uniform scale for these sectional maps 
would have been an advantage. The maps appear 
to be accurate and revised to date. The allocation of 
the Cameroons to the League of Nations on one map 
is apparently a slip. The atlas deserves a wide use. 
The All-Electric Age. By A. G. Whyte. 
242. (London: Constable and Co., 
47s. 6d. 
Mr. WHuyTE gives an interesting and accurate account 
of the latest electrical developments. He has refrained 
from speculating about the future, but we think that 
if he had pointed out the directions in which advances 
will probably be made he would have added to the 
interest of the book. 
Pp. xiii+ 
Ltd., 1922.) 
