240 
NATURE 
[May 9, 1912 
itself, not only in the taste of his renderings, but 
in his very pretty preface, and perhaps finds its 
best expression in the verses on the constellation 
Engonasin, the modern Hercules, with which the 
preface concludes. These verses are a perfect gem 
and an important addition to our not too large 
store of astronomical poetry. Another feature 
of the preface to which I would invite the 
attention even of those who do not wish 
to read the book is the brief, but critical, 
bibliography of modern works on _ ancient 
astronomy and astrology (pp. ix, x). Perhaps it 
is not too much to hope that the editor will permit 
this bibliography to be reprinted along with his 
verses in some astronomical journal, where they 
may interest readers who are not likely to see the 
present volume. J. K. ForHerincuaM. 
OUR BOOKSHELF. 
Practical Mathematics and Geometry. A Text- 
book for Advanced Students in Technical and 
Trade Schools, Evening Classes, and for 
Engineers, Draughtsmen, Architects, Sur- 
veyors, &c. By Edw. L. Bates and Fredk. 
Charlesworth. Part iii., Advanced Course 
containing numerous Practical Exercises, with 
Answers, and about 300 Illustrations. Pp. viii 
+447-776. (London: B. T, Batsford, 1911.) 
Pricengspanet. 
Tuis volume is in continuation of the subjects 
treated in parts i. and ii. by the same authors; 
these were reviewed in Nature of February 9, 
1911. The mathematical part of the present 
volume comprises sections dealing with trigono- 
metry, mensuration, algebra, and rates of in- 
crease. The geometrical portion includes tan- 
gential arcs of circles, loci, conic sections, 
vectors, and descriptive geometry. The difficulty 
of coordinating successfully the two main branches 
of the subject is evident in this volume as in its 
predecessor. Chapters dealing with geometry 
stand isolated among others of a mathematical 
character, there being no apparent connection. 
Perhaps the chapter on conic sections is the only 
one showing a real attempt at coordination. The 
trigonometrical portion is very brief, containing 
little more than the definitions of the functions of 
an angle and the solutions of triangles. It would 
be useful to have the relations of the sum and 
difference of two angles included in this volume. 
In many cases the authors are content with the 
mere statement of a rule; this probably is the 
result of taking cases from practice, not in illus- 
tration of principles already discussed, but as 
problems needing a solution. 
Descriptive geometry occupies the last seven 
chapters, and these may almost be regarded as a 
separate book. The matter includes projections 
of simple figures, planes, and plane figures in 
space, intersecting planes and lines, plane sec- 
tions, and developments of surfaces. The treat- 
ment of this portion of the volume, apart from 
NO. 2219, VOL. 89] 
what has preceded it, is good, and will give the 
student reasonable grounds for believing that he 
is acquiring some systematic knowledge of prac- 
tical geometry. 
Principles and Practice of Poultry Culture. By 
John H. Robinson. Pp. xvi+611. (London 
and Boston; Ginn and Co., n.d.) Price 
ros, 6d. 
Mr. Jonn H, Ropinson is one of the best-known 
poultrymen and one of the best-known writers 
on poultry matters in the United States. To 
say that his present work will be popular in the 
ordinary acceptation of the word with the British 
reader is perhaps saying too much, With the 
student, and more especially on the shelves of the 
professor of animal industry and in the college 
library, there it should be found, and not only 
found, but read. 
The chapters one would particularly like to 
mention for special quotation (if space permitted) 
are: iii, economic aspects of poultry culture; 
iv., the poultry keeper’s problems; vii., systems 
of poultry keeping; xii., poultry foods; 
xili., rations and methods of feeding; xxi., types, 
breeds, and varieties of fowls; xxii., turkeys; 
xxiil., ducks; xxv., phenomena and principles of 
breeding. It must be remembered that America 
has given us the Rock, the Wyandotte, the Rhode 
Island Red, and one of the best utility types of 
Leghorn. 
The Philo system of housing, the “dry feed” 
and ‘dry mash,” and the score card for teach- 
ing purposes all emanate from the States. This 
country has learnt much from the ‘other side.” 
Even for the illustrations alone, the book is 
well worth buying. We have purposely omitted 
to comment on the somewhat elaborate plants, 
as the climate in this country does not warrant 
such expense. As indicated above, the thought- 
ful reader will find much food for reflection, while 
the purely practical man will devour eagerly the 
definite directions, particularly those referring to 
ducks, geese, and turkeys. 
Geographical Pictures (from Photographs). Series 
ili.: Sculpture of the Earth’s Crust. Packet 
No. xr. Plates 1-6. Packet No. 2. Plates 7-12. 
(Wondon: A. and S@seBlack, “n.d>)iiebrce 
6d. per packet of six pictures. 
Messrs. Brack issue these illustrations, which 
measure about six by five inches, as part of their 
scheme of school geography. Packets 1 and 2 
are concerned with processes of weathering, and 
the pictures are described by Miss S. M. Nicholls. 
Their low price allows of the use of several copies 
in a class, the teacher pointing out the salient 
features, and the pupil following his remarks with 
the aid of the abridged description on the plate. 
The views of granite in the Scilly Isles, of wind- 
carved rocks in Colorado, and of the interior of a 
cave at Cheddar, seem particularly happy. The 
text is clear and to the point, though the two 
attempts to spell the Snowdon buttress, Crib-y- 
Didysgl and Cribs-y-Dysel, will not please Welsh- 
men. G. AeyaGe 
