34o 



NA TURE 



[September g, 1922 



The Individual and the Community. By R. E. Roper. 

 Pp. 224. (London : G. Allen and Unwin, Ltd., 

 1922.) 8s. 6d. net. 

 Mr. Roper has produced a thoughtful and, in many 

 respects, a stimulating book. He is a whole-hearted 

 evolutionist, who regards the failure of post-war recon- 

 struction as arising from the fact that our statesmen 

 have resorted to outworn precedents while neglecting 

 the teachings of evolution. There is, he maintains, a 

 wilful confusion of State and community. A com- 

 munity he defines as "an association of two or more 

 human beings for common (though not of necessity 

 identical or similar) purpose or advantage in their 

 evolution." Immediately the common purpose ceases, 

 the community also ceases. Taking each of the 

 principal States of Europe in turn, Mr. Roper shows 

 that, owing to the division which has been made and 

 is perpetuated by the financial-governing class between 

 themselves and the working-governed class, none of 

 them constitutes a community in his sense. The 

 imposition of the will of one section of society upon 

 another which is involved in our modern system of 

 government b\ the majority is therefore fundamentally 

 wrong. The difficulty is old, and if in practice we have 

 made no very essential advance beyond the compromise 

 expressed in Rousseau's distinction between le volatile 

 de tons and le volonti gtniral, it is an advantage that it 

 should be kept before our minds by the clear vision of 

 writers such as Mr. Roper. 



Metric System for Engineers. By C. B. Clapham. 

 (Directly-Useful Technical Series.) Pp. xii + i8i + 

 3 charts. (London : Chapman and Hall, Ltd., 1921.) 

 12s. 6d. net. 

 The author's justification for his book is that " even 

 among those who use the millimetre in drawing-office 

 or workshop there are probably few who feel confident 

 in calculating with metric units," and his object is to 

 explain the metric system and to state in full how to 

 convert from the English units to metric units, and 

 vice versa. Incidentally there is given an excellent 

 account of the vernier and other devices used by 

 engineers for accurate measurement. The book should 

 be of great use in industrial life : the conversion tables 

 are very exhaustive. 



A brief survey is offered of the controversy which 

 has been raging for so long round the question whether 

 the metric system should or should not be introduced 

 compulsorily in this country. It is claimed that this 

 survey is not a piece of propaganda work in favour of 

 the change, but the arguments given pro and con do 

 much to support the view, that a good deal of the 

 opposition to the enforced use of the metric system 

 in England is attributable to mere conservative objec- 

 tion to change. Mr. Clapham's book is itself one of 

 the best arguments in favour of the change — why 

 should the Englishman be condemned to waste so 

 much time and energy in making conversions and in 

 looking up tables of equivalents ? S. B. 



Wild Bush Tribes of Tropical Africa. By G. C. 



Claridge. Pp. 314. (London : Seeley, Service and 



Co., Ltd., 1922.) 21s. net. 

 Mr. Claridge's " Bush Tribes " are the Ba-Congo of 

 Northern Angola, and the country the inhabitants of 

 which he descri bes stretches from the Congo on the north 



NO. 2758, VOL. I io] 



to St. Paul de Loanda in the south, and from the Kwilu 

 and Kwangu rivers in the east to the Atlantic. He 

 writes of the native with sympathy, but, for the most 

 part, despises his customs : he rarely fails to stigmatise 

 them as " degrading," " disgusting," or worse when he 

 has an opportunity. Notwithstanding this drawback, 

 as it must seem to those who wish to study native 

 custom impartially, the author has given a full and 

 careful account of Ba-Congo culture, and his collection 

 of folk-lore is both interesting and useful. The most 

 important part of his book deals with fetishism, and, in 

 particular, with the N'Kamba fetish of the women, 

 which controls their most important function, that of 

 child-bearing. The men are rigorously excluded from 

 the rites of this fetish. A " Death and Resurrection " 

 secret society, which effects " cures " by death and 

 rebirth, is described from information supplied by a 

 native, but here unfortunately the author's prejudice 

 colours the narrative to such an extent that considerable 

 knowledge of similar societies is required to disentangle 

 the facts. 



Readable School Physics. By J. A. Cochrane. Pp. 

 xi + 131. (London: G. Bell and Sons, Ltd., 1922.) 

 2s. 4d. 



A teacher who loves his subject will find matter of 

 interest for his pupils even in its most prosaic parts. 

 " This book," writes Mr. Cochrane in an interesting 

 Preface, " is an attempt to humanise Elementary 

 Physics without popularising it." We are of opinion 

 that in this task the author has achieved very con- 

 siderable success. Theory has been given the main 

 prominence. Experiments have not been described 

 unless to elucidate principles. References to the 

 makers of scientific history are frequent, and are 

 reinforced by a number of interesting plates which 

 include portraits of Newton, Pascal, Boyle, Galileo, 

 and Joseph Black. The pupil's own experience is 

 brought into connexion with physical principles as 

 often as possible. Part 1, which might have been called 

 Mechanics instead of Hydrostatics since it includes 

 chapters on volume, weight, and density (not to 

 mention surveying), occupies about two-thirds of the 

 book, the remainder being devoted to what is certainly 

 a " readable " account of the elementary principles 

 of heat. 



Ions, Electrons, and Ionising Radiations. By Dr. J. A. 



Crowther. Third Edition. Pp. xii + 292 + ii pis. 



(London : Edward Arnold and Co., 1922.) 125. 6d. 



net. 

 The first edition of Dr. Crowther's useful manual has 

 already received notice in these columns (August 12 

 1920, p. 740.). The fact that a third edition has 

 been called for so soon is sufficient evidence that the 

 book has been appreciated. The material has been 

 thoroughly revised and the various tables of constants 

 brought into accord with the best data obtainable. 

 Siegbahn's work on X-ray spectra and Aston's work 

 on positive rays receive notice, and an account is 

 given of Sir Ernest Rutherford's recent work on the 

 problems of atomic structure and of Bohr's theory. 

 We have no hesitation in recommending this volume 

 to readers desiring a systematic account of the latest 

 developments in physics. 



