364 NATURE [FEBRuaARY 18, 1897 
sphere. In this sense, the amount of heat intercepted | of the various types of pumps, and affording information 
by the earth is so much less than that mentioned as to 
make the statement misleading. Such blemishes are 
perhaps slight, and might well be passed over where so 
much of the work is excellent and well arranged. But a 
graver charge, and one that will surprise many who take 
up the book, is the neglect to place Boyle’s law in a 
prominent position. One might go so far as to say that 
Boyle’s law is not even mentioned. It does not occur in 
the index, and we have not found any reference to it in 
the text, so that it must be very obscurely expressed ; 
and yet it seems imperative, that to such a fundamental 
principle great clearness and prominence should be given. 
We think, too, that the chapter on “atmospheric optics” 
might well have been omitted. There is nothing peculiar 
about “atmospheric optics,” and if one wanted to know 
the theory of the rainbow, one would necessarily go to a 
book on optics, and we should imagine that in the “high 
schools and colleges” in America, students are taught 
their optics more thoroughly than is suggested by the 
sketchy manner in which the subject is here treated. 
The most satisfactory chapters of the book are those | 
which describe the winds and the circulation of the 
atmosphere. 
Ferrel in his general explanation, and his intimate know- 
ledge of the work of this physicist has enabled him to 
give much valuable information in a succinct and accurate 
form. Unfortunately, it is precisely in this section of 
meteorology that some of the views now held are most 
likely to meet with modification, but the chapters are 
valuable as presenting in a popular form the present con- 
dition of our knowledge. Another special and valuable 
feature in the book is the collection of results that have 
been derived from meteorological observations. ‘These 
results are exhibited both in tabular and graphical form, 
and always clearly. Whatever may be thought of the 
value of many of the meteorological observations so per- 
sistently and energetically collected, there can be no 
doubt but through their means many useful facts have 
been learnt, which it is desirable to make known in the 
pleasantest manner possible. These results may end only 
in the knowledge of the climate of the district in which 
the observations have been .made ; they may not touch 
the general principles underlying the science of meteor- 
ology understood in its widest sense, but such results 
have a practical value in many arts and sciences, and it 
is a praiseworthy task to spread abroad a knowledge of 
the facts that have been collected, and likewise a grateful 
task to acknowledge the efforts of those who, like 
Dr. Waldo, have laboured on behalf of the service of 
meteorology. 
OUR BOOK SHELF. 
The Mechanics of Pumping Machinery. By Dr. Julius 
Weisbach and Prof. Gustav Herrmann. Translated 
from the second German edition by Karl P. Dahlstrom. 
Pp. 298. (London: Macmillan and Co., 1897.) 
PUMPING operations occupy an important place in 
engineering works, for they are required for keeping out 
the water from foundations during construction, for 
raising water from deep wells, for the disposal of sewage, 
for the efficient drainage of low-lying lands, and for pro- 
viding water under pressure for working hydraulic 
machinery. Accordingly, books explaining the principles 
NO. 1425, VOL. 55 | 
The author has closely followed Prof. | 
as to their relative efficiency, are valuable to engineers 
and contractors who are obliged to have recourse to 
pumping in their works. This book appears to be in- 
tended primarily for the instruction of students attending 
advanced courses on the mechanics of machinery ; but the 
descriptions and clear illustrations of the different forms of 
pumps, should prove useful to those practically engaged 
in the raising of water. The first chapter relates to the 
early forms of water elevators, such as the balanced pole 
with a bucket hung from one end and counterpoise at 
the other, known as the Pzcoftah in Bengal and the 
shadouf in Egypt, flash wheels, scoop wheels, chain 
pumps, and the archimedean and other water screws ; 
and the efficiencies of the wheels, chain pumps, and screws, 
are calculated. The three following chapters are devoted 
to the elementary action, the theory, and the various 
types of reciprocating pumps, the last subject extending 
over a hundred pages, or one-third of the book. Recipro- 
cating pumps may be divided intotwo classes, namely, those 
having hollow valved pistons, or bucket pumps, and 
those having solid pistons, or plunger pumps; and they 
comprise both lift pumps and force pumps, generally 
combining suction as well, and embrace the most common 
forms of machines for raising water, and also fire-engine 
and water-pressure pumps. The fifth chapter describes 
different forms of rotary pumps, of which the centrifugal 
pump is the most familiar example, and furnishes calcu- 
lations with regard to the form, velocity, and efficiency of 
these types of pumps. In the sixth and final chapter, the 
principles of the hydraulic ram, ejectors and injectors, 
spiral pumps, compressed-air pumps, the pulsometer, and 
syphons are explained with the aid of diagrams. The excel- 
lent woodcuts, indeed, 197 in number, dispersed throughout 
the text, elucidate the descriptions very efficiently. A 
table of contents at the head of each chapter would have 
been valuable for guidance, especially when a single 
chapter occupies one-third of the book, and also a list of 
the woodcuts, and headings to the principal illustrations ; 
whilst an index of barely more than a page, does not 
afford adequate opportunities of reference. The transla- 
tion has been so well performed, that the only reminders 
of the foreign origin of the book are the metric measures, 
after which have been added their English equivalents in 
brackets ; but in a book drawn up expressly for English 
readers, the calculations, as well as the results, should 
have been converted into English measures, to which the 
most prominent place should have been assigned, even if 
it was considered advisable to retain the foreign measures. 
Pumping machinery has so long formed a speciality of 
several English manufacturers, that English authors 
should have rendered it unnecessary to resort to Germany 
for an exposition of the mechanics of pumping machinery. 
Germans, however, have been long renowned for the 
thoroughness of their scientific investigations, and Mr. 
Dahlstrom, of Lehigh University, has performed a valu- 
able service in putting this book within the reach of 
American and British engineers and students. 
Geography of Africa. By Edward Heawood, M.A. Pp. 
vili + 262. (London : Macmillan and Co., Ltd., 1896.) 
THE publication of this little text-book in Macmillan’s 
Geographical Series will be welcomed by all who are 
interested in geographical education, or who desire a 
handy and trustworthy compendium on Africa. Books 
made up mainly of tables of chief towns, lengths of 
rivers, and other statistical information, are, we hope and 
believe, on the decline, and rightly so; for they repre- 
sent the worst methods of teaching geography. Through- 
out Mr. Heawood’s volume, the principles kept in view 
are: “In the first place, the rule laid down by Dr. Mill 
in the ‘General Geography’ of this series, of proceeding 
from the general to the particular, has been adhered to ; 
and in the second, a clear understanding of the broad 
physical features of each region described has been 
