April 14, 192 1] 



NATURE 



199 



seem to us to be exaggerated, and the present 

 moment is a particularly unfortunate one for such 

 a departure.) With this broad historical treat- 

 ment is happily combined an essentially modern 

 outlook when dealing with the details of the 

 subject. The new lines of advance opened up 

 by the development of physical chemistry receive 

 their full meed of recognition, and short chapters 

 are devoted to explaining the principles on which 

 these methods of investigation are based. Some of 

 these chapters are less satisfactory than others. 

 That on voltaic cells, for example, comprising 

 eleven pages, deals with a great range of topics 

 in what is necessarily a compressed and scrappy 

 fashion, and will not convey much to a reader 

 new to the subject. 



The descriptive portions of the book have been 

 critically compiled, though we think that more 

 scepticism might have been displayed in assigning 

 definite formulae to such classes of compounds as 

 basic salts, hydrated oxides, etc. Much recent 

 work is included, and the same applies to the 

 sections dealing with technical processes, where 

 it is pleasant to find an up-to-date treatment of 

 such subjects as sulphuric acid concentration and 

 the Deacon process, and a mention of electrostatic 

 precipitation, flotation processes, and electro- 

 magnetic separation. The relative importance of 

 a process is not, however, always reflected by the 

 : amount of space it occupies in the text. Blast- 

 furnace copper smelting is less adequately treated 

 than the Welsh process, and electrolytic alkali 

 processes are represented by one obsolete and one 

 obsolescent cell. 



Mistakes appear to be very few. Attention may, 

 however, be directed to the fact that in practice 

 calcium cyanamide is not produced in an arc 

 furnace (p. 544) ; also that Alfred, not Alphonse, 

 Werner was the author of the co-ordination theory 

 of valency (p. loii). 



The only criticism of the book, as a whole, that 

 we are inclined to make is that the author has 

 perhaps been too loath to omit details of minor im- 

 portance, or, as already indicated, subjects the 

 adequate treatment of which would demand con- 

 siderably larger space. The volume is large in 

 size, and the price correspondingly high. It con- 

 tains more material than is required for the 

 average Pass degree, but not enough for the 

 average Honours degree ; and these circumstances 

 may adversely affect the use made of it by uni- 

 versity students, for whom it is professedly de- 

 signed. But the book is so good that one must 

 hope that this will not be the case. 



It remains to congratulate the publishers on 



their share of the work. 



A. J. A. 



NO. 2685, VOL. 107] 



Our Bookshelf. 



The Subject Index to Periodicals. 1917-19. B-E. 

 Historical, Political, and Economic Sciences. 

 496 cols. (pp. 248). (London : The Library 

 Association, 1921.) il. is. net. 



This section of the "Subject Index to Period- 

 icals," indexing papers on historical, political, 

 and economic sciences, contains above 12,000 

 entries taken from more than 400 English and 

 foreign periodicals published during the years 

 191 7-19. Though it is not a catalogue of science, 

 the economic problems affecting the development 

 of industrial science are indexed. Folk-lore is no 

 longer included in this list, but has been trans- 

 ferred to List A : Theology and Philosophy. 

 Headings relating to Prehistoric Man and to 

 local Topography are to be included in List G : 

 Fine Art and Archaeology. Among the subjects 

 indexed in the present list are "Commercial 

 Aeronautics," "Agriculture," "Chemicals: Manu- 

 facture and Industry," "Coal Trade," "Industrial 

 Efficiency," "Electric Industries," "Ethnology," 

 "European War," "Factories," "Fisheries," 

 "Forestry." "Food Supply," "Iron Industry," 

 "Labour," "League of Nations," "Military Art 

 and Science," "Railways," and "Sociology." 



Those who are interested in problems connected 

 with the changed economic conditions brought 

 about by the war will find in this list the titles of 

 most of the papers that have been published on 

 these subjects during the three years indexed. 

 The catalogue will also have an historical interest 

 as showing what we were all thinking about 

 during the second half of the war period. 



Y ear-Book of the Scientific and Learned Societies 

 of Great Britain and Ireland. Thirty -seventh 

 Annual Issue. Pp. vi4-354. (London: Charles 

 Griffin and Co., Ltd., 1920.) 155. 

 We welcome the thirty-seventh edition of this 

 useful annual, which is invaluable as a guide to 

 the many scientific societies, of local as well as 

 of more general interest, in the United Kingdom. 

 In it will be found a record of the work done in 

 science, literature, and art during the academic 

 year 1919-20, and it is gratifying to note that the 

 small increase in price is balanced by an increase 

 in size of nearly twenty pages, which testifies 

 amply to the further activities of our men of 

 science. The volume is divided into a number of 

 sections dealing respectively with science gener- 

 ally ; astronomy ; mathematics and physics ; 

 chemistry ; geography and geology ; biology ; 

 economics ; mechanical sciences ; naval and mili- 

 tary science ; agriculture ; law ; literature and 

 history ; psychology ; archaeology ; and medicine. A 

 noteworthy feature is the inclusion of particulars 

 from scientific institutions and departments con- 

 nected with Government service. Among these 

 are the Meteorological Office, the National 

 Physical Laboratory, the Geological Survey, the 

 Natural History Museum, the Ministry of Health, 

 the Medical Research Council, the Royal Observa- 



