270 
Notices of Books. 
[April, 
Problems and Examples in Physics. An Appendix to the 
Seventh and other Editions of Ganot’s “ Elementary 
Treatise on Physics.” London : Longmans and Co. 
The author of this pamphlet, Mr. E. Atkinson, remarks in his 
Preface that — “ The present book, consisting of a series of nu- 
merical problems and examples in Physics, is based upon a 
similar one contained in the French edition of the work. But I 
have been able to use only a small proportion of the problems 
contained in that Appendix, as the interest of the solution was 
in most cases geometrical or algebraical. Hence I have substi- 
tuted or added others, which have been so selected as to involve 
in the solution a knowledge of some definite physical principle.” 
We consider the substitution thus referred to by the author a 
decided improvement. 
The Applications of Physical Forces. By Amedee Guillemin. 
Edited by J. N. Lockyer. London : Macmillan and Co. 
i 8 77 - 
This forms the companion volume to the “ Forces of Nature ” 
of M. Guillemin, a translation of which appeared in this country 
five years ago. The present work is published in the same 
form, with numerous and elaborate woodcuts and coloured plates : 
the one deals with pure science; the other with some of the more 
prominent applications of the sciences. 
The work is divided into five books, which treat respectively 
of the applications of the phenomena and laws — i. Of Weight. 
2. Of Acoustics. 3. Of Light. 4. Of Heat. 5. Of Magnetism 
and EleCtricity. 
We must take exception to the title of the first book : to speak 
of the phenomena of weight when we mean the phenomena due 
to a force, one of the effects of which is to produce the effeCt we 
call “ weight,” is surely an example of misplaced diclion. 
This book treats of plumb-lines and levels, pile-drivers, the 
pendulums of clocks, and balances. In the second seCtion, of 
the hydraulic press, hydrometers, liquid levels, pumps, fire- 
engines, and air-pumps. The atmospheric railway is described, 
but no mention is made of the use of air-pumps for exhausting 
vacuum-pans. The applications of compressed air comprise 
the air-gun (which is surely the least important application) and 
the boring of tunnels by a compressed air-engine. Compressed- 
air railways are beginning to make their appearance in various 
cities : in Paris small parcels are conveyed from the Grand 
Hotel to the Place de la Bourse at the rate of 40 feet a second. 
The pressure of air is produced by the pressure of water (equal 
