July 29, 1922] 



NATURE 



14; 



Problemes et exercises d'electricite generate. Par Prof. 

 P. Janet. Pp. vii + 254. (Paris : Gauthier-Villars 

 et Cie, 1921.) 



Prof. Janet gives an interesting collection of problems 

 which have been set in the entrance examinations for 

 the Higher School of Electricity in Paris. Many of 

 the problems are novel, and in some cases it is shown 

 how the solution can be obtained by several different 

 mathematical methods. The examples are purely 

 theoretical, so exact solutions ran be given. They are 

 expressed in nearly every case by algebraical formulae, 

 numerical illustrations being left to the student. The 

 English reader will find the latter part of the book very 

 instructive, as the author frames his problems so as to 

 take into account mechanical as well as electrical 

 considerations. For example, the instantaneous values 

 of the currents depend on the moments of inertia of 

 the moving parts of the machines as well as on the 

 inductances of the circuits. We hope this innovation 

 will be followed in English text-books. The students 

 are supposed to have a thorough knowledge of electrical 

 principles and to be familiar with the calculus. We 

 can recommend this book to teachers. A. R. 



Thought-Coin. By Bart Kennedy. Pp. x + 219. 

 (London : W. Rider and Son, Ltd., 192 1.) 5s. net. 



The title gives no clue to the contents of this book, 

 ft is not. as might be imagined, one of those pseudo- 

 scientific works urging a one-sided belief in the all 

 potence of thought, nor is it a psychological treatise 

 on thought-processes. It is an attempt to consider 

 some of the problems of life, such as dreams, con- 

 sciousness, grouping, sex, etc., not as abstractions but 

 as living realities ; it is a frank acceptance of facts as 

 against the " oughts " and " its " of so many writers, 

 and so far is more truly scientific than some of the 

 more apparently scientific books. The author surveys 

 the universe with the vision of the seer, and gives to 

 problems which are so often treated in isolation the 

 background of relation to the universe. All life is for 

 him an ever provocative mystery. He writes with a 

 penetrating imagination, but imagination controlled 

 and vitalised by the teaching of science. It is interest- 

 ing to read scientific problems expressed in terms of 

 imaginative literature. 



The Evolution of Consciousness. By A. W. Tilby. 

 Pp. 256. (London : T. Fisher Unwin, Ltd., 1922.) 

 15s. net. 



Mr. Tilby writes with a vivacity and humour which 

 make his book exceedingly pleasant reading. It 

 contains no original research, but it is exceptionallv 

 well-informed. The idea is outwardly very like that 

 of Bergson's creative evolution, and may have been 

 suggested by it — that consciousness in every form, 

 instinctive and intellectual, is a product of the evolu- 

 tion of life and utilitarian in its purpose. There is an 

 essential difference, however, in the fact that Mr. 

 Tilby recognises no interpretative principle such as 

 that which, for Bergson, makes evolution creative. 

 All that is, Mr. Tilby tells us. has emerged in a definite 

 historical sequence, and we have merely to accept the 

 fact and not ask why. The inert we are led to under- 



NO. 2752, VOL. I 10] 



stand preceded the living, and even memory is a purely 

 material fact. 



F. C. Donders. Reden gehallen bei der Enthiillung 

 seines Denkmals in Utrecht, am 22. Juni 1921. Von 

 Prof. Dr. C. A. Pekelharing, Dr. Sikkel, Dr. A. F. 

 Baron van Lijnden, Dr. J. P. Fockema Andreas, aus 

 dem Hollandischen iibersetzt von Paula Krais geb. 

 Engelmann. Pp. 62. (Leipzig : W. Engelmann, 

 1922.) Fl. 1. 



The unveiling of a statue of F. C. Donders last summer 

 at Utrecht was the occasion for the delivery of several 

 addresses on his life and work. These have been 

 collected, translated into German and issued as a small 

 illustrated booklet. Donders was the founder of 

 modern teaching on the accommodation and refraction 

 of the eye, his great work on which was published in 

 1864. He was a prolific writer, and a list of his papers 

 (1840-1883) is included : some of his latest contribu- 

 tions deal with colour-blindness. 



The Microscope : A Simple Handbook. By Conrad 

 Beck. Pp. 144. (London : R. and J. Beck, Ltd., 

 1921.) 2S. 6d. net. 



Mr. Beck has in this little book collected and set out 

 in elementary form a considerable amount of informa- 

 tion useful to the microscopist. The optics of the 

 instrument are described in a simple manner, and a 

 final chapter deals with pond-life as objects for the 

 microscope. Published by Messrs. R. and J. Beck, 

 the book avowedly deals with the products of that 

 firm, but is none the worse for that so long as the 

 reader is aware that other makers of microscopes 

 exist. We can commend this account of the micro- 

 scope to the beginner, who will find in it clear directions 

 for use and explanations of many difficulties. 



R. T. II. 



Reports of the Progress of Applied Chemistry. Issued 

 by the Society of Chemical Industry. Vol. 6, 192 1. 

 Pp. 638. (London : Society of Chemical Industry, 

 46-47 Finsbury Square, n.d.) -js. 6d. to Members ; 

 12s. 6d. to Non-members. 



Reference has previously been made in Nature to 

 the very useful annual reports issued by the Society 

 of Chemical Industry. This year the report is of the 

 same high standard as its predecessors. A particu- 

 larly noteworthy feature of the separate reviews of the 

 progress made during the year, each written by a 

 specialist, is that the matter is treated critically. The 

 reports are essential to those who wish to follow the 

 progress of chemical industry, and should be in the 

 hands of technical chemists, teachers, and students, 

 all of whom will find matter of interest in them. 



Practical Polishing and Staining. By A. W. Park- 

 house. Pp. viii + 120. (London: Benn Bros., Ltd., 

 1922.) 85. 6d. net. 



Mr. Parkhouse writes from practical experience, and 

 his book is a very readable and well-informed account 

 of the subject. He very properly lays stress on the 

 importance of close co-operation between the polisher 

 and the cabinet maker, and his book may be recom- 

 mended to both. 



