December g, 1922] 



NA TURE 



767 



Empire Water-Power. 



Water-Power in the British Empire. The Reports of 

 the Water-Power Committee of the Conjoint Board of 

 Scientific Societies. Pp. ix + 54. (London, Bombay, 

 and Sydney : Constable and Co., Ltd., 1922.) 

 2,s. 6d. net. 



IT is just about twelve months since reference 

 was made to the third and final Report of the 

 Water-Power Committee of the Conjoint Board of 

 Scientific Societies (Nature, December 8, 1921, 

 p. 457). In the little book before us the whole 

 of the results of the investigations made by the 

 committee, as set forth in the three successive reports, 

 are embodied. This compact statement of the present 

 position of the British Empire in regard to the develop- 

 ment of its water-power resources will be welcome to 

 all who are interested in the matter, either from a 

 purely scientific or from a utilitarian and practical 

 point of view. It represents the outcome of four years 

 of valuable research work, carried on with unremitting 

 activity by the committee under the capable direction 

 of the chairman, Sir Dugald Clerk, and with the 

 energetic and painstaking assistance of the secretary, 

 Prof. A. H. Gibson. 



Sir Dugald Clerk contributes to the volume a preface 

 of a very thoughtful and stimulating character. He 

 tells us that the 46 million people now living in the 

 United Kingdom require an expenditure of energy of 

 io£ million horse-power for their support, and that 

 while this supply of power is undoubtedly forthcoming, 

 for the present, from our stock of coal, yet our reserves 

 of natural fuel are bound to diminish, and in time to 

 be depleted, so that we shall be obliged to fall back 

 upon other agencies to make good the deficit. Taking 

 the United Kingdom as a whole, there appears to be 

 continuously available (24 hour period) a total of 

 1,350,000 horse-power, or if any great tidal scheme, 

 such as that of the Severn, be included, perhaps a 

 total of 1,750,000 horse-power. This is, of course, 

 insufficient to replace the work done by means of coal- 

 fired engines, but, at least, it would represent a very 

 substantial saving in fuel. 



On the other hand, this power is not all economically 

 realisable, or rather the cost of obtaining the whole 

 of it would be higher than is justified, as yet. In 

 Scotland, however, some 183,000 horse -power is 

 immediately feasible, at a cost appreciably less than 

 that of coal-fired stations built and operated under 

 existing conditions. Even in England and Wales, a 

 large proportion of the quota is commercially obtain- 

 able. It is obviously a matter, then, of national 

 concern to devise means for making use of these 

 natural power supplies, which are running to waste, 

 NO. 2771, VOL. I IO] 



if only for the purpose of supplementing the work 

 which is at present done by our far from inexhaustible 

 supplies of coal. 



The report covers a wider field than Great Britain ; 

 it embraces the resources throughout the British 

 Dominions, and its carefully compiled figures will lie 

 of considerable assistance to those whose interest lies 

 in the promotion of water-power schemes at home or 

 abroad. Brysson Cunningham. 



Our Bookshelf. 



Modern Electrical Theory. Supplementary Chapters. 

 Chapter XV. : Series Spectra. By Dr. N. R. 

 Campbell. (Cambridge Physical Series.) Pp. viii + 

 no. (Cambridge: At the University Press, 1921.) 

 105. 6d. net. 



The work now before us is one of the supple- 

 mentary chapters to Dr. Campbell's book on modern 

 electrical theory. This series of supplements is 

 planned according to an idea which might well be 

 used by the authors of other text-books on physics. 

 It is unfortunate, however, that we are unable to 

 commend the present book to those who, like the 

 reviewer, welcomed the author's original work as a 

 real and vital account of the subject. The book con- 

 tains numerous errors which any practical spectro- 

 scopist would detect at once ; and they reach their 

 culminating point when the author, in a professedly 

 complete list of the chemical elements the spectra of 

 which form well-defined series, omits oxygen, sulphur, 

 and selenium. The spectrum of oxygen is, almost in 

 a classical sense, one of the most beautiful and ideal 

 series arrangements known to every spectroscopist. 

 It has not played a part in the application of the 

 quantum theory as yet, which may provide the 

 explanation of the circumstance that the author is 

 unaware of this fact, as he shows more than once. 



The genesis of this book is quite clear. The^author 

 has read Bohr's recent work on the " Correspond- 

 ence Principle," and, like every other reader, has 

 been very much attracted by it. He has also con- 

 sulted all the Danish and German writings, and he 

 gives a really excellent account of them in a very non- 

 technical style. Dr. Campbell appears, however, to 

 be unaware of the contribution of this country to the 

 subject, and of the practical details of spectra. The 

 second deficiency explains why all the facts of spectra 

 which he gives correctly are those which foreign writers 

 have quoted in support of the quantum theory. Follow- 

 ing the usual assumption that all the significant work 

 on the subject has been done abroad, anything written 

 in English is mostly ignored or misquoted. It is 

 difficult, indeed, to find an English name in the whole 

 work. A treatise on any branch of this subject 

 which never refers to the fundamental work of Jeans, 

 dismisses that of Fowler with a casual mention of his 

 least important contribution, credits Nicholson with 

 a mere suggestion that the angular momentum in an 

 atom might have discrete values, and finally never 

 mentions W. Wilson, who anticipated Sommerfeld in 

 the fundamental generalisation, while putting it on a 



