264 



NATURE 



[April 28, 192 1 



specially engaged in the Survey, checking their 

 reconnaissances, and making further researches in 

 British India and the Native States. 



Part i. of the report consists of a note by Mr. 

 Meares on the general principles of development 

 and storage of vv^ater for electrical purposes, com- 

 piled for the guidance of those making local in- 

 vestigations, and exhibits the standard form in 

 which it is recommended that the data collected 

 should be recorded. Part ii. deals with adminis- 

 trative matters connected with the Survey. 

 Part iii. contains the results of the reconnaissances 

 made by the chief engineer and the electrical 

 adviser, together with observations on the pro- 

 vincial surveys. Decisions were made as to the 

 suitability or otherwise of various localities for 

 further investigation. Difficulties, however, were 

 encountered which prevented in several cases any 

 very effective progress, and it is stated that until 

 additional staff can be recruited and an adequate 

 supply of survey instruments assured it will not 

 be possible for the work to proceed on more satis- 

 factory lines. Brysson Cunningham. 



The Principles of Politics: An Introduction to the 

 Study of the Evolution of Political Ideas. By 

 Prof. A. R. Lord. Pp. 308. (Oxford : At the 

 Clarendon Press, 1921.) 85. 6d. net. 

 Prof. Lord modestly describes his book as a 

 bridge for students from Sir Frederick Pollock's 

 " History of the Science of Politics " to Dr. 

 Bosanquet's "Philosophical Theory of the State." 

 In this task he has succeeded well. His style is 

 eminently readable, his arguments are clear, and 

 his information is accurate. His analyses of poli- 

 tical theories are supported by apt quotations, in 

 the selection of ,which — e.g. from Spinoza's poli- 

 tical writings and from the Federalist — he has de- 

 parted, with excellent effect, from the traditional 

 text-book grooves. The introductory chapter 

 gives a good account of the influence of the Re- 

 naissance and the Reformation on political theory. 

 There follows a chapter on the social contract, 

 three chapters on different theories of sovereignty, 

 one on democracy and representation, one on the 

 notion of law, three on the theory of rights, and 

 lastly a conclusion in which Prof. Lord sums up 

 his own positive point of view, which is that of the 

 classical idealist theory of the State, as developed, 

 under the influence of Kant and Hegel, by T. H. 

 Green and Bosanquet. It is a little to be re- 

 gretted that Prof. Lord's scheme did not permit 

 him to touch on the recent criticisms of this theory 

 by writers like Graham Wallas, G. D. H. Cole, 

 H. J. Laski, R. H. Tawney, and many others. 

 He keeps strictly to historical materials. Hobbes. 

 Locke, Rousseau, and Spinoza are the prominent 

 figures, with Machiavelli, Bentham, and Burke in 

 the second rank. No nineteenth-century theorists 

 find mention except Mill and Spencer, and these 

 only in the discussion of individualism. However, 

 within these self-imposed limits Prof. Lord has 

 written a book which teachers and students of 

 political theory alike will find useful. 



R. F. A. H. 

 NO. 2687, VOL. 107] 



Abnormal Psychology and its Educational Applica- 

 tions. By F. Watts. Pp. 191. (London : 

 George Allen and Unwin, Ltd., 192 1.) ys. 6d. 

 net. 



The first edition of this book, published under the 

 title of "Echo Personalities," received notice in 

 Nature for July 17, 1919, under the title "Ab- 

 normal Psychology and Education." When a 

 second edition was asked for, the author accepted 

 the obvious suggestion and adopted a title which 

 is more likely to indicate the scope of the book. 

 Few changes have been made in the new edition ; 

 the chapters have been usefully subdivided, 

 while those on psychopathology and the develop- 

 ment of personality, and on the psychology of the 

 defective mind and its influence on teaching 

 methods, have received considerable additions. 

 The chapter on the psychology of the supernormal 

 mind finds no place in the new edition. 



Tables of Physical and Chemical Constants, and 

 some Mathematical Functions. Bv Dr. 

 G. W. C. Kaye and Prof. T. H. Laby. Fourth 

 edition. Pp. vii4-i6i. (London: Longmans, 

 Green, and Co., 192 1.) 14s. net. 

 The changes which have been made in the new 

 edition of this valuable manual of constants are 

 mostly matters of detail. All the chemical data 

 have been recalculated on the basis of the inter- 

 national atomic weights, and, with the co-opera- 

 tion of Dr. E. Griffiths, of the National Physical 

 Laboratory, a revision of the heat tables has been 

 attempted. Tables of atomic numbers, spark-gap 

 voltages, X-ray wave-lengths, and terrestrial mag- 

 netic constants also find a place in the new 

 edition, and more extended tables of the relative 

 value of the acceleration of gravity have been 

 added. The first edition received detailed notice 

 in Nature of February 8, 1912, 



The Theory of Relativity. By Prof. R. D. 

 Carmichael. Second edition. (Mathematical 

 Monographs, No. 12.) Pp. 112. (New York: 

 John Wiley and Sons, Inc. ; London : Chapman 

 and Hall, Ltd., 1920.) 85. 6d. net. 

 The earlier portion of Dr. Carmichael's book is 

 a reprint of the first edition, which received notice 

 in Nature for March 12, 1914. The later pages, 

 which are grouped together under one large 

 chapter with twelve subheadings, deal with the 

 generalised theory of relativity. The new chapter 

 opens with a brief summary of results obtained 

 from the restricted theory, and an account of the 

 general theory follows. Sufficient detail is given 

 to provide some explanation of the general theory 

 of gravitation, the nature of the three phenomena 

 by which experimental proof of the theory may 

 be expected, and the connection between the 

 generalised theory and Maxwell's electromagnetic 

 equations. Applications of the theory other than 

 those which are immediately associated with the 

 fundamental ideas or with phenomena for testing 

 the validity of the theory have been omitted in 

 order that attention may be directed more readily 

 to the more novel aspects of the theory. 



