NATURE 
| MarcH 10, 1904 
have the head and neck grey and not black like the 
“corbies’’ in the background. There is evidently 
some error about these figures, for they are referred 
to throughout the book as Plates i., ii., &c., whilst the 
corresponding numbers are only marked on them ex- 
ceptionally and sporadically. 
But although the illustrations are not so good as 
could be wished—and all who have had experience in 
similar matters know how very difficult it is to secure 
good figures of animals—the perusal of the present 
book may be recommended to all who are interested 
in the animal life of India. Veet: 
ENGINEERING SCIENCE. 
Strength and Elasticity of Structural Members. 
R. J. Woods, M.Inst.C.E. Pp. xi+310. 
E. Arnold, 1903.) Price 10s. 6d. net. 
URING the last fifteen years there has been a 
rapid growth in the number of engineering 
students taking a full course at one or other of the 
many institutions in Great Britain and America which 
offer instruction in the necessary subjects, and as a 
result there has been a steady stream of text-books 
By 
(London : 
written especially for this comparatively new class of | 
college students. The strength and elasticity of 
materials is a branch of engineering science which 
must be thoroughly mastered by every student, no 
matter to what branch of engineering he eventually 
proposes to devote himself. It is not surprising, there- 
fore, that a number of text-books devoted to this sub- 
ject have been published during the past few years, and 
it is hence a somewhat difficult matter for any author 
to show much originality in his treatment of the 
problems which have to be solved. Mr. Woods has, 
however, been able to deal with several points in a 
fresh and interesting manner. The book will be 
especially valuable to the private student on account 
of the very excellent series of examples at the end of 
each chapter, with the solutions given in every case. 
The first chapter is devoted to graphical statics, and 
after simple definitions of the triangle and polygon of 
forces, the funicular polygon, and the graphical con- 
ditions of equilibrium, the methods of solution are ex- 
plained, and then applied to the practical problems of 
the graphical determination of stresses in roofs, 
girders, and framed structures. In the next three 
chapters the relations between stress and strain are very 
fully and carefully discussed, the properties of the 
ellipse of stress are deduced, and the results are 
applied to the determination of the principal stresses 
in a In a text-book of this nature it is 
important that tables should be 
given of the weights, strengths, and other proper- 
ties of the various materials used by engineers in 
structural work, and it may be well to point out that 
the tables given on pp. 72 and 73 might have been 
considerably increased, and certainly would have been 
improved, by the addition of a column giving the 
elastic limit in tension for such materials as wrought 
iron, mild steel, &c. 
In dealing with bending and bending moments, a 
slight inversion of the actual order adopted would 
NO. 1793. VOL. 60} 
beam. 
very complete 
probably have facilitated the reading of the private 
student, that is to say, in chapter v. it would have been 
better to have placed the formulz connecting stress 
and bending moment at the end rather than at the 
beginning, after all the preliminary work of determin- 
ation of bending moment, drawing of shear and bend- 
ing moment diagrams, &c., had been fully treated. 
The author has introduced into the chapters dealing 
with beams the graphical methods for finding the 
equivalent area or modulus of section of beams; this 
useful piece of work is too often omitted from the 
ordinary text-books. 
As the book was originally written in the form of a 
series of lectures for students at the Royal Indian 
Engineering College, it naturally deals with one or 
two branches of the subject not usually considered in 
elementary text-books; for example, stresses at the 
joints in masonry structures, stresses due to earth 
pressure at the back of retaining walls, and the 
strength and design of riveted joints for structural 
work, are all fully discussed. The book is a good, 
clearly written text-book, and will probably be a useful 
work of reference not only to the engineering student, 
but to those engaged in actual practical work. 
Glo lel. 18h 
SCHOOL GEOMETRY. 
Theoretical Geometry for Beginners. 
Part iii. By 
C. H. Allcock. Pp. viii+113. (London: Mac- 
millan and Co., Ltd., 1904.) Price 1s. 6d. 
Elementary Geometry. Section iii. By Frank R. 
Barrell, M.A., B.Sc. Pp: viii + 285 | tomes60: 
(London: Longmans, Green and Co., 1904.) Price 
1s. 6d. 
Rudiments of Geometry for Junior Classes. By M. 
Wilson. Pp. 228. (London: W. R. Russell and 
Co.) Price 1s. net. 
Geometry on Modern Lines. For Elementary Students. 
By E. Springfield Boulton, M.A. Pp. viii+ 126. 
(London: Methuen and Co., 1904.) Price 2s. 
HE text-book by Mr. Allcock, of which part iii. is 
now issued, is an excellent substitute for Euclid 
for those teachers who wish to confine attention mainly 
to deductive geometry. Experimental and practical 
work is not entirely omitted, but it occupies a very 
subordinate place. The book very attractive on 
account of its admirable and incisive style and the 
beautifully clear manner in which it is got up and 
printed, and it cannot fail to give satisfaction 
wherever adopted. The present part includes the more 
important propositions of Euclid, Book ii., also Book 
iii., Props. 35-37, and Book iv., Props. 10-16. In 
many cases the algebraical equivalents follow the 
geometrical proofs, and mutually illustrate one 
another. In some of the propositions it would have 
been a great advantage if simple  trigonometrical 
equivalents could also have been given. A useful 
chapter on the radical axis is included, and answers 
to the numerical examples are collected at the end of 
the book. 
The geometry by Mr. Barrell displays very com- 
mendable originality in the manner of presentation. 
is 
