896 



NA TURE 



[December 22, 1923 



The book gives a good summary of those branches 

 of knowledge which it handles, a summary which can 

 l>c read with profit by young students who want to get 

 A general view of what they are learning : it is more 

 like an index than an exposition. Many will differ 

 from tlic translator, who has otherwise jjcrformcd his 

 task well, over his decision to express the extreme 

 numl)ers. usually written in index notation, in words, 

 such as a " (|uadrillionth part of i^ grams," or " 800 

 billion per second." It is true that he gives a table 

 of this notation in his introduction, but the scheme 

 is of doubtful advantage. 



(3) Now Mr. Ikrtrand Russell has succeeded in 

 writing a book on the atom which is really accessible to 

 the general reader. He uses a simple and lively style, 

 which does not disdain to find in the flea '.' which crawls 

 for a while and then hops " an image of the motion of 

 the electron in the Bohr atom. His book is very read- 

 able, and gives what is in the main a very good account 

 of the fundamental features of modem atomic theory. 

 Unfortunately, Mr. Russell's unfamiliarity with the 

 practical side of physics has led him into some extra- 

 ordinary statements, such as that a spectrum which is 

 " a continuous band of colours, like a rainbow/' is 

 called a band spectrum, or that fluorescence is " the 

 subsequent emission of light of exactly the same 

 frequency as that which has been absorbed," or that, 

 " broadly speaking, there are three lines, the K, L, and 

 M lines, which make up the X-ray spectra." The 

 author makes an attempt, which seems a little too 

 ambitious, to expound Hamiltonian mechanics without 

 symbols. He has, obviously, written mainly under the 

 influence of Sommerfeld's book : to have rendered some 

 of the main lines of thought in that book comprehensible 

 to a wide circle of readers is no mean feat. 



(4) Dr. Norman Campbell appeals to a different circle, 

 that of students who are specialists in physics. He 

 continues the task of bringing parts of his " Modem 

 Electrical Theory " up-to-date by means of monographs 

 which he calls chapters. The book before us shows some 

 of the valuable qualities which physicists have learnt 

 to associate with its prolific author, whose impulsive 

 claim and vivacious enthusiasm in the cause of progress 

 find frequent expression in such a passage as : 



" If we are hidebound by tradition, let us by all means 

 stick to Amperean and Maxwellian theory, reject as a 

 pernicious heresy, unsanctioned by the Fathers of the 

 Church, all modem theory of spectra ; let us retire as 

 hermits to the desert of ignorance and refuse to have 

 iuiy dealings with the wicked, bustling world of modem 

 science. If, on the other hand, we believe that progress 

 in science is not impossible, and that the age of discovery 

 did not end abruptly in 1870, let us be confident in our 

 beliefs, and attribute to genius in our own time an 

 authority no less and no greater than that of our 

 intellectual forbears." 



NO. 2825, VOL. 112] 



It is regrettable that this spontaneity of utteran< < 

 seems to be allied to a breathless haste which has IkI 

 to the omission of all mention of important pieces 01 

 work, and a certain carelessness which impairs mui !i 

 that has been written. It is, no doubt, outside the 

 design of the Ixxjk to devote attention to the methods 

 of experiment by which the knowledge has been won. 

 but, even so, it seems questionable to say of the p * " 

 rays that they " are never homogeneous in vti 

 and so to ignore all Dempster's work. It is scarce! > 

 fair to Aston to say that he merely " re-designed 

 Thomson's apparatus." It is strange to refer in detail 

 to the discrepancy' between the Bohr and the Weiss 

 magneton, and to say nothing of Pauli's theor\' or of 

 the work of Gerlach and Stem. Nobody is more 

 impressed with the advisability of correctness in 

 dimensions than Dr. Campbell, and yet he gives A. a 

 unit of action, in ergs on page ix, whDe according to 

 his equations on page 82 and elsewhere it is erg cm. ! 

 The notation is at variance with that of chapter xv., and 

 is not consistent in the book itself. The index is futile. 



Unfortunately these faults are but typical : it would 

 be a distasteful task, but an easy one, to extend the list. 

 Maturer reflection would, it seems certain, have led Dr. 

 Campbell not only to introduce certain modifications in 

 his exposition, but also to cancel his abuse of Sir William 

 Ramsay, which serves no good purpose. The con- 

 clusion is irresistible that the author could have written 

 a very much better book if he had only been willing 

 to take more trouble and more time over it. 



E, N. DA C. Andrade. 



Our Bookshelf. 



Electrical Engineering Practice : a Fr act teal Tnu..^. ,. 

 Electrical, Civil, and Mechanical Engineers, with many 

 Tables and Illustrations. By J. W. Meares and R. E. 

 Neale. Fourth edition, rewritten and enlarged. In 

 2 vols. Vol. I. Pp. x + 584. (London : Chapman 

 and Hall, Ltd., 1923.) 255. net. 



In the new edition of Meare's and Neale's '' Electrical 

 Engineering Practice," the scope of the work has been 

 widened and the matter has been suitably rearranged. 

 The book is thoroughly up-to-date and reflects clearly 

 the present state of the industrial knowledge of elec- 

 trical engineering in Great Britain. The authors are a 

 little hampered at times by having to keep closely to 

 the specifications and nomenclature definitions of 

 the British Engineering Standards Association (the 

 B.E.S.A.), the Wiring Rules of the Institution of 

 Electrical Engineers, and the recommendations of the 

 Intemational Electrical Commission. The B.E.S.A. 

 has always many committees sitting revising specifica- | 

 tions for materials, machines and apparatus and deal- 

 ing also with nomenclature and s\-mbols. As these 

 specifications are issued periodically it is not easy for 

 authors to keep pace with them. The committees are 

 not necessarily bound by their pre\-ious decisions. For 

 example, the older generation of electricians recom- 



