266 



NATURE 



[May 15. 1913 



in considerable detail. These, together with the 

 appendices concerning radio-active constants, 

 ranges of particles, rates of decay, &c, cannot 

 fail to be of the utmost use to those interested in 

 the extension of knowledge in this sphere. Lack 

 of space forbids as detailed a description as the 

 work deserves, but it can be confidently stated that 

 it will prove its own recommendation. 



(3) This is the first of a series of four little books 

 on practical physics which the author proposes to 

 publish. It is intended to form in schools a first 

 year's course, and deals with measurements in 

 mechanics of solids and fluids. The instructions 

 are given in a very clear manner, and the student 

 is told in every case exactly how to record the 

 results. The arrangement of the book and the 

 diagrams are excellent, rendering it quite one of 

 the best of its kind. 



(4) This is another book on practical physics, 

 but one of a much more extensive and advanced 

 character. The experiments described are those 

 on general physics and properties of matter which 

 are suitable for the advanced classes in colleges 

 and technical schools. A knowledge of the calcu- 

 lus is assumed, being used for the theoretical 

 treatment of many of the exercises. Students are 

 instructed in the methods of eliminating errors, 

 and advised as to the precautions necessary to 

 secure accurate results. The author has been very 

 thorough in this respect, and his work compares 

 favourably with the various standard text-books of 

 practical physics. 



(5) Here is yet another book on elementary 

 practical physics for use in schools. The two 

 volumes deal respectively with mechanics, and heat 

 and light. The method adopted is to ask a series 

 of questions, the answers to some of them depend- 

 ing merely on theoretical knowledge and the others 

 involving practical observations. In all cases 

 space is provided in the book itself for the student 

 to record the answers and results beneath the 

 exercise itself. This certainly seems to be carry- 

 ing this method of teaching a little too far, for in 

 the case of the slovenly student (he result will be 

 that the book will be spoilt, while to the tidy 

 student such spoon-feeding is quite unnecessary. 

 The instructions given are rather meagre, and no 

 diagrams are used for purposes of illustration. 



(6) Ur. Lecher's book is a simple treatise on 

 physics specially intended for students of medi- 

 cine and biology. The author has endeavoured to 

 make the subject appeal to them by the frequent 

 introduction of illustrations drawn from their own 

 subjects. Naturally the book is quite elementary 

 in character, but the scope is fairly comprehensive 

 from a descriptive point of view. Some of the 

 diagrams are rather old-fashioned, depicting, as 



NO. 2 272, VOL. QI.l 



they do, persons performing experiments, but they 

 are well and clearly printed, as is also the text. 



(7) A book such as this of Dr. Houstoun's has 

 long been needed. Many students of physics have 

 experienced considerable difficulty both in select- 

 ing and in understanding the various treatises on 

 mathematical physics which they ought to read. 

 The present work will serve as an introduction to 

 a variety of subjects, and the treatment is such 

 that a student with a fair knowledge of the calculus 

 and physics should be able to read it with com- 

 parative ease. The six chapters of the book deal 

 respectively with attraction, hydrodynamics, 

 Fourier series and the conduction of heat, wave 

 motion, electromagnetic theory, and thermo- 

 dynamics. There is also a series of examples at 

 the end of each chapter. One is inclined to think 

 that the section on thermodynamics is scarcely so 

 extensive as the subject deserves, at any rate in 

 comparison with the space devoted to the other 

 sections. Standard works on thermodynamics 

 are, however, more readily available to the average 

 student ; consequently this defect is less serious 

 than it might otherwise have been. 



(8) In this little popular treatise on electrii it\ 

 Prof. Adami manages to describe in non-mathe- 

 matical language various principles in electricity 

 and their applications to important practical 

 developments. The book is nicely got up, and the 

 diagrams are exceedingly well produced. 



OUR BOOKSHELF. 

 The Electron Theory. By Prof. Toshinojo 



Mizuno. Pp. 336. (Tokyo: Z. P. Maruva 



and Co., Ltd., 1912.) 

 In this book, which is intended for Japanese 

 readers, Prof. Mizuno, of Kyoto Imperial 

 University, gives the substance of a course of 

 lectures which he delivered in iqn at the Kyoto 

 summer school. Beginning with the vacuum tube 

 discharge, the author leads his readers through 

 the various phenomena associated with the Zee- 

 man effect, Brownian movements, Lenard and 

 Rontgen rays, up to the modern conceptions of 

 the structure of the atom. In this connection the 

 hypothetical forms of stable configurations are 

 discussed at considerable length. There then 

 follow fairly detailed sections on the constitution 

 of the spectrum lines, on radio-activity, on the 

 energy quantum theory, on the longitudinal and 

 transverse mass of electrons, and the like. To- 

 wards the end the principle of relativity is intro- 

 duced in connection with Michelson and Morley's 

 classical experiments. 



The author makes no claim to any originality 

 of treatment ; but he has made himself master 

 of the growing literature of the subject and has 

 endeavoured to give a connected view of the many 

 phenomena described. He is not satisfied with 



