December 28, 191 1] 



NATURE 



275 



mathematical; the business of the mathematician (as 

 Kirchhoff and Pearson have so well pointed out) is to 

 provide, if possible, a descriptive scheme, such, for 

 instance, as the so-called " law " of gravitation and its 

 mathematical consequences, which reduces a complex 

 group of phenomena to an intelligible system. Any- 

 thing beyond this is metaphji-sics, and outside the 

 domain of ph}'sical science and mathematics as well. 



G. B. M. 



APPLICATIONS OF PHOTOGRAPHY IN 

 SCIENCE AND TECHNICS. 

 Angewandte Photographie in Wissenschaft und Tech- 

 nik. Edited by K. W. Wolf-Czapek. In vier Teilen. 

 Pp. xvi+ 100 + 37 plates; pp. 119 + 41 plates; pp. 

 95 + 42 plates; pp. 98 + 37 plates. (Berlin: Union 

 Deutsche Verlagsgesellschaft Zweigniederlassung 

 Berlin, 191 1.) Price 20 marks. 



THERE is scarcely a science to-day wherein photo- 

 graphy is not employed in one form or another, 

 and even our industries make use of it in a host of 

 different ways. So universal has become the adoption 

 of this form of obtaining permanent records of things 

 living and inanimate that specialists have sprung up 

 in all directions who are able to bring to bear a great 

 amount of experience, not only in how to apply photo- 

 graphy to the particular case in question, but the most 

 appropriate apparatus and methods to be adopted to 

 secure the best results. 



If, for instance, one wishes to launch out in the 

 domain of photomicrography the first step is to find 

 out what has been written on the subject, and then 

 secure a book which is recommended as containing 

 the best methods to be followed. Or, again, the 

 special field of photographing fast-moving objects, like 

 rifle bullets, is one that requires a good deal of atten- 

 tion before satisfactory results can be obtained. It 

 often happens that one wishes to tackle one branch 

 of photographic work which is outside the domain 

 of that to which one is accustomed, and hence there 

 follows an inquiry into the methods, special apparatus, 

 and material required. 



Now the work under review is a veritable vade 

 incctim in this respect, for it deals, and deals exceed- 

 ingly well, with the application of photography in 

 practically every important aspect, both in science and 

 the technics. It is only natural that for such a volume 

 to be of value it must necessarily be the work of 

 numerous men, for no one man can have had experi- 

 ence in all the multitude of applications. Herr K. W. 

 Wolf-Czapek has done well therefore in gathering 

 round him a number of workers who are authorities 

 on the branches about which they write, and the result 

 is one that is eminently satisfactory. The book itself 

 contains 407 pages and 159 plates, with 470 illustra- 

 tions on them, so that the reader will at once 

 gather the fact that both methods and examples 

 are amply illustrated and described. The contents are 

 divided into four parts under general subheads, 

 namely (i) inorganic physical sciences, such as 

 physics, chemistry, astronomy, &c. ; (2) organic 

 physical sciences, such as botany, zoology, &c. ; (3) 

 technical science, such as photography applied to war, 

 NO. 2200, VOL. 88] 



engineering press, &'C. ; and lastly (4) social problems, 

 as anthropology, criminal statistics, &c. The list of 

 coworkers is too numerous to be given here, but when 

 it is seen the reader can rest content that the text 

 was in good hands. It-is interesting to note that the 

 volume was inspired by the International Photographic 

 Exhibition held in Dresden in 1909, and that Herr 

 Wolf-Czapek took the opportunity to utilise the ex- 

 hibits as the groundwork for the volume. 



In addition to a very carefully prepared table of 

 contents, a subject-index and a name-register, the 

 value of the work is considerably enhanced by the 

 large number of references to the literature of the 

 various subjects treated. 



AGRICULTURE AND SOILS OF KENT, 

 SURREY, AND SUSSEX. 

 Board of Agriculture and Fisheries: a Report on the 

 Agriculture and Soils of Kent, Surrey, and Sussex. 

 By A. D. Hall, F.R.S., and Dr. E. J. Russell. 

 Pp. viii + 206 + 56 figures. (London : H.M. 

 Stationery Office, 191 1.) Price 2s. 6d. 



A BRIEF introductory account is given of the 

 geological features of the area under considera- 

 tion. This is followed by a concise account of the 

 agriculture of the three counties as practised at the 

 present day, chief reference being made to the cultiva- 

 tion of hops and fruit, for which this part of England 

 is famous. Attention is also directed to the most 

 important breeds of live stock found in the districts, 

 the Southdown and Romney Marsh sheep receiving 

 special notice. 



The latter portion of the report is devoted to the 

 authors' work upon the soils of the three counties. 

 This section contains a valuable record of analyses— 

 both mechanical and chemical— of the soils of the 

 different localities. Messrs. Hall and Russell have 

 taken the geological formations as a basis of work, 

 and find that the analyses of the soils upon each 

 formation exhibit certain common features which 

 mark them off from those of other formations. 



By a careful study of the results, it is seen that the 

 mechanical analysis is, in a general way, indicative of 

 the power of the soil to grow particular crops success- 

 fully, and a knowledge of the character and proportion 

 of the component particles is frequently sufficient to 

 enable the expert to predict with certainty the suitability 

 of the soil to the cultivation of hops, fruit, roots, wheat, 

 and other cereals. The chemical analyses in many 

 instances also clearly indicate the need for particular 

 fertilisers, and practical recommendations are made 

 for the manuring of the various farm crops when 

 grown on land situated on the different geological 

 formations. 



The authors modestly suggest that the report is 

 incomplete and fragmentary. It is, however, one of 

 the most valuable contributions made to the study 

 of soils in this country, and it is to be hoped that some 

 effort will be made to secure a continuance of similar 

 work in other areas and on an extended scale. We 

 should like to see the analysis of soils undertaken in 

 conjunction with carefully planned experiments upon 

 Ii, ,. ,1 fields from which the samples are drawn, 



