304 



NATURE 



[March 9, 1922 



Our Bookshelf. 



An Agricultural Atlas of Wales. Made on behalf of 

 the Institute for Research in Agricultural Economics, 

 University of Oxford, by J. Pryse Howell. Pp. iii 

 + 23 maps + 3 maps in pocket. (Southampton: 

 Ordnance Survey, 1921.) 55. net. 

 It is to be hoped that the enterprise of the Ordnance 

 Survey in publishing an agricultural atlas of Wales 

 will be rewarded sufficiently to facilitate the publica- 

 tion of similar atlases for regions of England. Mr. J. 

 Pr}^se Howell has worked at agricultural surveys for 

 years at Aberystwyth and at Oxford, and the present 

 atlas does considerable credit to his care and industry. 

 It is based on parochial returns, and consists of twenty- 

 three maps, one for each agricultural product. There 

 are also three loose maps in colour giving the orography, 

 geolog>', and rainfall of Wales, and as the agricultural 

 maps are on translucent paper they can be super- 

 imposed on the loose maps in order to trace correlations. 

 It is a pity that the revision of Welsh geology is not 

 yet sufficiently complete to give a better representa- 

 tion of the stratigraphy of West Wales based on the 

 work of Prof. 0. T. Jones and the correlation with 

 geological facts. The correlations traceable often 

 depend more on the drift than on the solid geology, 

 though these maps of Wales are mostly of a kind 

 simpler than one would find in England, for in Wales 

 the greater part of the surface is impervious soil on 

 hard rocks, and agriculture is dominated by oro- 

 graphical conditions which so greatly influence rain- 

 fall. In England the influence of soil would be more 

 complex. 



The agricultural relations of the belt between the 

 Vale of Clwyd and the Dee at Corwen, of the lower 

 Montgomeryshire Severn, the parallels between pigs 

 and potatoes, and many other points, stand out clearly, 

 while the curious distribution of lucerne, sainfoin, 

 clover, and grasses under rotation prompts a number 

 of questions. The atlas should be used widely by 

 agriculturists and economists, by persons interested 

 m local administration, and by teachers, especially 

 teachers of geography. 



The Silver Bromide Grain of Photographic Emidsions 

 By A. P. H. Trivelli and S. E. Sheppard. (Mono- 

 graphs on the Theory of Photography from the 

 Research Laboratory of the Eastman Kodak Co.) 

 Pp. 143. (New York: D. Van Nostrand Co.: 

 London: Kodak, Ltd., 1921.) 155. 

 The research laboratory of the Eastman Kodak Co. 

 has m preparation a series of monographs on the 

 theory of photography. The time is ripe for the 

 presentation in a connected sequence of the work 

 done and the results obtained, for these are very 

 numerous and very scattered. The present volume 

 is the first issued, and presumably may be regarded 

 as a sample of those that are to follow. The company, 

 the laboratory, and the authors are to be congratulated 

 in that they have made so good a beginning. The 

 authors have been engaged for some years in the 

 practical study of the subject with which they deal, 

 and they give some results that have not been pub- 

 lished before. A study of the relations that exist 

 between the sizes of the grains and their photographic 

 NO, 2732, VOL. 109] 



properties is reserved for a future monograph, though 

 it is by no means neglected in the present treatise. 

 The first half of the volume deals with the influence 

 of ammonia on photographic emulsions and a theory 

 of ripening ; von Weimarn's theory and the determina- 

 tion of the dispersity of silver bromide precipitates ; 

 accessory factors influencing the dispersity of silver 

 bromide emulsions ; crystallisation catalysis ; and 

 capillarity and crystalline growth. The intimate 

 relation between grain structure and photographic 

 properties is, however, fundamentally a matter of 

 crystallographic investigation, and the remainder of 

 the volume is devoted to this matter in five chapters. 

 The authors state that " when the experimental con- 

 ditions regulating the three primary factors, (i) 

 dispersity-distribution, (2) recrystallisation, and (3) 

 sorption (both adsorption and desorption), are com- 

 pletely known, scientific control of the characteristic 

 curve— z.e. of speed, latitude, and density— will be 

 possible." The book is copiously illustrated and well 

 indexed ; it has many summaries, all necessary 

 references, and an extensive bibliography. C. J. 



Indian Science Congress : Handbook for the Use of 

 Members attending the Ninth Meeting to be held at 

 Madras from the Thirtieth of January to the Fourth 

 of February, 1922. Pp. x+165. (Madras: Capt. 

 Clive Newcomb, Chemical Examiner, 1921.) 

 The Indian Science Congress has held annual meetings 

 in various parts of India yearly since 19 14 much on 

 the lines of the British Association for the Advance- 

 ment of Science, and the handbook issued for this 

 year's meetings contains a number of interesting 

 articles by experts, including a brief history of Madras 

 and its Corporation, descriptions of the museum and 

 Connemara Public Library, the Madras Harbour, the 

 new city waterworks and the chlorination purification 

 of the supply, and an interesting account of places of 

 historical interest within twenty miles of the city. 

 General education in Madras is dealt with by the 

 principal of the Presidency College, and medical 

 education by the principal of the Medical College. 

 The remainder of the little book is occupied with 

 accounts of scientific work in the Presidency in different 

 branches of knowledge, and includes the work of the 

 King Institute of Preventive Medicine, situated several 

 miles from the city and concerned chiefly with hygiene, 

 and an interesting account of the valuable practical 

 investigations being carried out at the Agricultural 

 and Research Institute at Coimbatore by the Director 

 of Agriculture. Contributions on prehistoric archae- 

 ology, the anthropology of Southern India, marine 

 zoology, the geology of Madras, and biological work 

 there, complete an instructive handbook which is very 

 suitable for the purpose for which it has been designed. 



L. R. 



Treatise on Fractures in General, Industrial, and 

 Military Practice. By Prof. J. B. Roberts and 

 Dr. J. A. Kelly. Second edition, revised and 

 entirely reset. Pp. x + 755. (Philadelphia and 

 London : J. B. Lippincott Co., 1921.) 42s. net. 

 The authors of this volume have set out, as they claim 

 in their preface, to present a lucid view of the subject 



