Fuly 28, 1870] 
NATURE 
253 
to trace the connection which subsists between storms 
and Barometric differences. 
We have also in these journals papers on Ozone, from 
Dr. Mitchell and Prof. Crum Brown ; and in the physio- 
ogical branch of the science we have observations on 
crops, trees, birds, &c., besides an interesting paper by | 
Dr. Mitchell, on the cause of some of the pernicious effects 
of polar winds. 
Besides the Fournals of the Scottish Meteorological 
Society, we have received two pamphlets written by Mr. 
Charles Chambers, Director of the Bombay Observatory, 
which are of much value to men of science as thoroughly 
scientific discussions of phenomena observed with instru- 
ments of precision. In one of these, entitled ‘““The Normal 
Winds of Bombay,” we have a full analysis of the climate of 
that part of India as far as the element of wind is concerned. 
In another pamphlet by the same author, forming paré 
of the Zyansactions of the Royal Society of London, we 
have the magnetic phenomena of Bombay discussed in 
a very able manner after the method first introduced by 
General Sir E. Sabine and followed now by most mag- 
neticians. If we have yet made little advance in assigning 
the causes of magnetic variations, we have at least in such 
pages as these a solid foundation upon which to build, 
and our progress in terrestrial magnetism in this respect 
contrasts favourably with what we have achieved in 
former years. : BALFOUR STEWART 
DONKIN'S ACOUSTICS 
Acoustics: Theoretical. Part I. By W. F. Donkin, M.A., 
F.R.S., &c., Savilian Professor of Astronomy, Oxford. 
Pp. 202. (Clarendon Press, 1870.) 
|? the Delegates of the Clarendon Press are able to 
carry out their programme, it will be possible before 
long for English students to learn Physics in their native 
language. Besides Thomson and Tait’s “Natural Philo- 
sophy,” which, ifcompleted in the same way as it has been 
begun, will be a book for a nation to be proud of, they 
promise usa series of separate educational treatises on the 
several branches of Physics. Of these there are already 
published Dr. Balfour Stewart’s excellent treatise on Heat, 
and the work mentioned at the head of this notice. This, 
unhappily, is only a fragment, forming part of the general 
theoretical introduction to a treatise on Sound and the 
principles of Music which the author did not live to write. 
But, although its quality is such as to make us keenly 
sensible of the loss which English science has suffered by 
the author’s removal before he had completed the work, 
the part that is published treats of subjects of so funda- 
mental a nature, and so little dependent on what would 
have followed them, that its intrinsic value is probably not 
much lessened by the absence of the remainder. 
The first chapter begins with a general description of 
the mechanism of the ear ; thisis followed by an explana- 
tion of the mode of representing vibratory movements by 
periodic curves, and a discussion of the nature of pitch, 
and of the principle of the superposition of vibrations, as 
bearing upon the distinction between noises and musical | 
sounds, and upon the general mode of perception of sounds 
by the ear. The second chapter is headed “ Miscellaneous 
Definitions and Propositions,” and is chiefly occupied 
with the mode of defining musical intervals, and with the 
statement of their most important relations. The third 
' at right angles to each other. 
chapter treats of the analytical representation of simple 
harmonic vibrations, and of the composition of vibrations 
The fourth chapter treats 
of the properties of the harmonic curve, of the composition 
of harmonic curves, and of Fourier’s Theorem. The 
fifth, sixth, and seventh chapters are devoted to the vibra- 
tions of elastic strings, the greater part of the sixth being 
| occupied with the description and experimental treatment 
of the important subject of forced oscillations, and an 
appendix to the same chapter with the mathematical 
theory of them. The eighth chapter treats of the longi- 
tudinal vibrations; and the ninth and last, of the 
transverse vibrations of elastic rods. The greater part of 
the book is addressed to mathematical readers, but much 
of it may be read with profit by students whose mathe- 
matical acquirements are very moderate. The evidence 
throughout the work of the author’s mastery of his 
subject gives to it a freshness and individuality which 
are in strong contrast to the characteristics of the un- 
digested compilations which form so large a part of the 
literature of physics. C, FOSTER 
OUR BOOK-SHELF 
Daily Readings in Natural Science. By Rev. J. Robertson, 
(London: C. Bean. 1870.) 
THIS book has been prepared for beginners in the study 
of Natural Science ; it is clearly and pleasantly written ; 
each day in the week during a term has its subject allotted 
to it, either on Natural History, Physics, Botany, Astro- 
nomy, Natural Phenomena, Chemistry, Geology, Manu- 
factures, Animal Physiology, or Applied Chemistry. The 
chapters are short, with questions at the end of each for 
the use of teachers. Mr. Robertson has written several 
other similar books, which he uses in his own school, 
and his success as a teacher lends great weight to 
the following extract from the preface :—“It is hardly 
necessary to descant lengthily upon the advantage of 
introducing science teaching into schools. The author, 
however, may be pardoned for giving his experience 
of adding science to the usual course of studies among 
his own boys. The science classes in his school had 
not long been established before he found that those 
boys who took no interest in their ordinary work soon 
manifested a quickness and brightness in dealing with 
natural objects that was quite remarkable, so much so, 
that after the first three months he doubled the time de- 
voted to science by the upper form, and commenced new 
classes for the benefit of the middle and lower forms. 
Speaking generally, the study of Natural Science quickens 
a boy’s powers of observation and comparison ; he learns 
to express his thoughts in proper logical order, his judg- 
ment is developed, and the tendency that all boys have to 
form hasty conclusions is checked and tempered.” To 
these we may join the following practical hints on con- 
veying scientific instruction to schoolboys, in a notice to 
teachers at the end of the book:—‘To be of real use 
science must be taught practically. Experiment and de- 
duction should go hand in hand, and a boy ought never 
to be called upon to commit a fact to memory the truth 
of which he has not previously seen demonstrated. This 
of course presupposes perfection in the way of apparatus 
and specimens, a state of things that may possibly exist 
some day at such magnificent centres of learning as Eton, 
Harrow, or Rugby, but the boy who by circumstances is 
obliged to pass his days at smaller establishments, must 
take for granted a large number of the facts with which 
he stores his memory. But the ingenious teacher will see 
a thousand ways of demonstrating facts to his pupils with 
the outlay of very little money ortime. The short course of 
