January 26, 1922] 



NATURE 



lOI 



to prepare ammonium nitrate on a large 

 scale. The synthetic processes for the pro- 

 duction of ammonia are described very briefl} 

 in a single column, but this is in accord with the 

 classification of the former edition, where a full 

 description of these processes is reserved for a 

 later article under " nitrogen." The revision, as a 

 whole, has been well done, and the new edition 

 .an be commended heartily as an accurate pre- 

 >entation of the state of applied chemistry after 

 the vicissitudes of recent years. 



(2) The publishers of le Blanc's "Text-book of 

 Klectro-chemistry " have adopted a simpler 

 method of meeting the demand for a new edition. 

 Although the title-page is dated 1920, the trans- 

 lator's preface bears no date. No references later 

 than 1907 have been discovered by the reviewer, 

 and the table of equivalents is certainly more than 



n years old. In view of the rapid growth of 

 e science of electro-chemistry, further comment 

 is scarcely necessary. 



(3) Prof. MacDougall's book contains an attrac- 

 tive and lucid account of the principal applica- 

 tions of thermodynamics to chemistry. The author 

 writes as a chemist rather than as a mathe- 

 matician, and, instead of giving merely an occa- 

 sional numerical illustration of his equations and 

 formulae, has provided quantitative data even when 

 these are scarcely needed to elucidate the text. 

 Thus it is a pleasure to find a full list of specific 

 heats of the solid elements, a table of the heat- 

 capacities of gases and of the ratio of their 

 specific heats at different temperatures, as well as 



Iiiseful tables of the heats of formation of metallic 

 tnd non-metallic compounds and of heats of solu- 

 tion, combustion, and neutralisation. In the same 

 jfvay the later chapters contain useful tables of 

 ^lectrode-potentials, equivalent conductances, ion- 

 bation-coefficients, transference numbers, and 

 ionic conductances. In dealing with the phase 

 rule, one chapter only is devoted to theoretical 

 considerations, whilst three chapters are required 

 to cover the various examples which the author 

 as selected to illustrate the applications of the 

 le. Another valuable feature of the book is the 

 insertion at the end of each chapter of a large 

 number of problems. These are of a very prac- 

 cal character, and illustrate clearly the many 

 ays in which a knowledge of thermodynamics 

 ay be made use of in the study of chemical 

 oblems. Certainly no book with which the re- 

 iewer is acquainted presents the subject in a 

 anner more likely to prove attractive to the 

 hem i St. 



T. M. L. 

 NO. 2726, VOL. 109] 



Prices and Wages. 



Prices and Wages: An Investigation of the 

 Dynamic Forces in Social Economics. By P. 

 WalUs and A. Wallis. Pp. xii + 456. (London : 

 P. S. King and Son, Ltd., 192 1.) 25s. net. 

 ''T^HE authors of this volume are, it may be 

 L gathered from the preface, business men 

 without much literary experience. The conse- 

 quent defects of the book, it is to be feared, 

 render it unlikely that many readers will be found 

 with sufficient patience to attempt the whole. 

 Four hundred and fifty pages of reasoning and 

 criticism are at the best a heavy task; when the 

 reasoning is often obscure and unnecessarily ver- 

 bose, when the criticism seems often ill-informed 

 or based on misunderstanding, the task is apt to 

 become almost unendurable. 



The argument appears to be as follows : 

 (i) The value of the net annual production, per 

 head of persons engaged in the industry, for any 

 one commodity, tends to fluctuate in the same 

 way as for any other commodity ; this agreement 

 is much closer than for prices. (2) These fluctua- 

 tions in the value of net annual production are 

 due to fluctuations in the value of the money 

 standard. (3) The value of the net annual pro- 

 duction per head, at any one time, tends to be 

 nearly the same for all commodities, including 

 the money standard. (4) Wages and salaries tend 

 approximately to the same proportion of the net 

 annual production per head. (5) It follows from 

 (3) and (4) that the annual wage-rate in any in- 

 dustry tends to be equivalent to the net annual 

 production of gold per head for the same grade 

 of labour in the gold-mining industry. (6) The 

 approximately constant proportion of wages and 

 salaries to total net annual product is due to the 

 competition of unemployed labour ; the mainten- 

 ance of this pool of unemployment is the real 

 failure of capitalism. 



It should have been obvious even to unprac- 

 tised writers that ordinary terms should not be 

 'employed in senses widely divergent from com- 

 mon usage. This rule has not been followed. 

 The value of the net annual production per head 

 of any commodity is spoken of throughout as its 

 " normal price," with the result that the argu- 

 ment falls at times — for the reader if not for the 

 authors also — into the most hopeless confusion. 

 The reader comes across some phrase about 

 " normal commodity prices " — dissents from it 

 — passes on — and only perhaps some time later 

 when wearied with an argument that seems to 

 him nonsense may it occur to him that the authors 

 did not mean normal prices at all, in the ordinary 



