60} 
NATURE 
[AUGUST 15, 1912 
in the light cf new methods of investigation, has 
been very successfully carried out in the first part, 
which deals with the experimental side of heat. 
While the fundamental treatment of the subject 
has not been neglected, special attention has also 
been directed to comparatively recent work. The 
chapters on the various methods of measuring 
temperature and that on the liquefaction of gases 
are both excellent, and will greatly add to the 
usefulness of the text-book. The second part is 
devoted to the consideration of the principles of 
thermodynamics, which, for the most part, are 
expressed clearly and in a simple manner. Several 
important applications of the principles are shown, 
and a large number of numerical examples, both 
in this and the first part of the book, are given. 
There is, however, a rather serious misstatement 
in connection with the meaning of the second law. 
After stating this law in the form due to Clausius, 
viz. “It is impossible for a self-acting machine, 
unassisted by any external agency, to convey heat 
from a colder to a warmer body,” the author at 
a later stage makes the statement, ‘It must be 
remembered that this law applies only to engines 
working in reversible cycles and to reversible 
cyclic processes.” This undoubtedly suggests that 
a self-acting engine performing an_ irreversible 
cycle may convey heat up temperature. In fact, 
all actual self-acting engines do perform irre- 
versible cycles of operations, and surely they are 
not to be regarded as cases of violation of the 
second law. What is probably meant by the 
above unfortunate statement is that cyclic pro- 
cesses only must be considered. With regard to 
the scope of the book, the standard is about that 
required for pass degree examinations, and the 
elementary use of the calculus has very properly 
been adopted. 
(2) In writing this book the authors have added 
another to the already numerous works of this 
Ikind. respects it 1s similar to others 
previously reviewed in these pages. Instructions 
for the performance of a large number of experi- 
ments in the various sections of physics are given, 
each description being accompanied by a few 
In many 
questions bearing on the experiment. Some of 
the questions seem rather unnecessary. In the 
experiment on the simple pendulum, for instance, 
the student is supposed to have discovered that 
T varies as 4/1, and is then asked if T varies as 
Z : F 
ie which is quite obviously contradictory to 
NS ; 
his previous discovery. 
I nu } 
iy 
T= Orr / 
\ fon 
o 
provided 7 and 1 are known. 
the spectrum are unsatisfactory. 
NO. Ra3 
Again, he is told that 
, and is asked if g can be computed 
The experiments on 
The student is 
supposed to be able to distinguish between con- 
tinuous and line spectra, using a slit } in. wide 
and no lens system. 
(3) This book is quite an unusual one, and 
deals with a most interesting subject. It is 
primarily designed for those who contemplate 
taking up work in the varied fields of lens design, 
illuminating engineering, colorimetry, photo- 
graphy, radiometry, pyrometry, etc. A training 
in theoretical optics is assumed, and only those 
possessing this will thoroughly appreciate the book 
in all its detail. A great deal of information is 
compressed into a small volume, and the sudden- 
ness with which the subjects change on this 
account is vather embarrassing to the reader. 
This is particularly the case with the introduction, 
where a general description of the results of 
investigations in light is crowded into twenty-five 
pages. Nevertheless the book is a considerable 
step forward, and may be regarded as a sort of 
forerunner to a more pretentious treatise, which 
the author hopes will presently be produced. 
(4) This is a class-book upen the same lines as 
the author’s “Elements of Mechanics.” It treats 
in quite an elementary fashion of the fundamental 
principles of the statics of liquids and gases. 
Applications to the determinations of specific 
gravities are given, and various forms of apparatus 
depending on the principles are described. 
Numerous examples, taken from university 
examination papers, are appended to the chapters. 
(5) This book is also quite elementary in charac- 
ter, and includes all that is required for the Junior 
Local Examinations. The author claims to dis- 
courage the use of mathematical formule, yet they 
appear to occur quite as frequently in this book 
as in others of the same type. It is true, however, 
that many numerical examples of the application 
of the formule are given. 
FOOD AND HYGIENE. 
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(2) Text-book of Hygiene for Teachers. By Dr. 
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Price 4s. 6d. 
(3) Experimental Domestic Science. 
Jones. (Heinemann’s 
1X + 235. 
By R. Henry 
Science Manuals.) Pp. 
(London: W. Heinemann, 1912.) 
Price 2s. 6d. 
(1) HIS book consists of the chemical and 
microscopical sections of the 1900 
edition, revised and extended. It is intended for 
