45^ 



NA TURE 



[February i8, 1909 



impress itself on anyone wiio refers to the 

 Physikalische Zeitschrift or the publications of the 

 Vienna Academy. The references in the present 

 volume are evidence of Prof. Gockel's familiarity, not 

 merely with recent work in German, but also with 

 that in English, whether done here or in America. 

 He makes, for instance, numerous references to 

 .Simpson's observations in Lapland. 



The book consists of a three-page introduction, five 

 chapters, and a short conclusion, and has a table of 

 contents. Chapter i., pp. 4 to 61, deals with the elec- 

 trical conductivity of the atmosphere. After describing 

 Elster and Geitel's dispersion apparatus, and the in- 

 struments of Ebert and of Gerdien for measuring 

 ionic charges and conductivity, it gives an account of 

 the results obtained with these instruments by different 

 observers in different places, and deals with the ques- 

 tions of diurnal variation and the influence of various 

 meteorological conditions. Chapter ii., pp. 62 to 120, 

 deals mainly with the potential gradient and its deter- 

 mination by means of water-droppers, flame and 

 radium collectors. This includes the results obtained 

 — especially in recent years — at the ground and those 

 derived from balloon ascents. The diurnal and annual 

 variations in the potential gradient, the relationships 

 of potential gradient and ionisation, and the influence 

 of meteorological conditions are amongst the subjects 

 discussed. Chapter iii., pp. 120 to 149, describes the 

 measurements by Gerdien and others of the vertical 

 current in the atmosphere, deals with the charges 

 brought down by rain and snow, and includes two 

 or three pages on aurora. As evidence of its up-to- 

 date character, it may be mentioned that it describes 

 Mr. C. T. R. Wilson's apparatus for measuring the 

 earth-air current. Chapter iv. is devoted to earth- 

 currents. Its length, only gi pages, forbids much 

 detail, but there is an account of several of the more 

 important observations, including those by Weinstein 

 in Germany. Chapter v., pp. 159 to 202, deals with the 

 sources of ionisation in the atmosphere. It discusses 

 the radio-activity of air from the ground, and of rain, 

 and the radio-active emanation in springs, the observa- 

 tions made by Elster and Gcitel and others with nega- 

 tively charged wires, and refers to recent work by 

 Gerdien, Rutherford, Strutt, Campbell, Dike, Eve, and 

 others. A few pages at the end relate to various 

 theories. 



In a book of such modest dimensions it is inevitable 

 that some parts of the subject should not be very fully 

 discussed, but it is unquestionably a work which 

 every serious student of atmospheric electricity should 

 possess and study. Very few points call for criticism. 

 There are, however, two historical references which 

 seem to overlook the work of British investigators. 

 Mascart is referred to on p. 80 as the first to introduce 

 photographic registration of potential difference, but 

 in reality the Kelvin water-dropper at Kew has re- 

 corded photographically since 1861. Again, the dis- 

 covery of the resemblance between the diurnal varia- 

 tions of potential gradient and barometric pressure is 

 said on p. 114 to have been made by Hann in iSSg. 

 Prof. J. D. Everett, however, detected it in 1S67 (/'/;//. 

 Trans., vol. clviii., p. 358, and plate xxi.). 



C. CUREE. 

 NO. 2051, VOL. 79] 



OUR BOOK SHELF. 

 The Ethical Aspects of Evolution, regarded as the 



Parallel Grozvtli of Opposite Tendencies. By W. 



Benett. Pp. 220. (O.Kford : The Clarendon 



Press, 1908.) Price 6s. net. 

 This book is full of original opinions vigorously and 

 uncompromisingly expressed. As the title indicates, 

 the author's main thesis is that the process of evolu- 

 tion does not mean the progressive elimination of evil 

 and pain, or a progressively increasing surplus of good 

 and pleasure. He adduces biological evidence to 

 show that the organism which has attained the finest 

 adjustment to its environment is the organism which 

 can be most easilv thrown out of adjustment, and the 

 one to which misadjustment, when it comes, is most 

 disastrous. So history teaches us that if civilisation 

 has meant higher forms of virtue, it has also meant 

 lower depths of vice ; and that as our knowledge in- 

 creases so does the consciousness of ignorance. 



From this point of view, Mr. Benett makes an effec- 

 tive destructive criticism on all optimistic evolutionary 

 theories of ethics which have as central principle the 

 possibilitv of perfect adjustment and the extrusion of 

 all inharmonious factors from experience. He then 

 proceeds to put forward his own theory. Failing the 

 criterion of a net surplus result of progress in good 

 or pleasure, Mr. Benett holds that our system of 

 valuations must rest on the conception of progress 

 itself. A teleological basis, he admits, would be more 

 adequate. But we are unable to find any finite end 

 which will give unity to the divergent tendencies of 

 human nature; and the transcendental end, though 

 we are compelled to posit it, is for ever beyond our 

 ken. The essential characteristic of progress is, for 

 Mr. Benett, increase of force; it is this which in the 

 last possible analysis commands man's esteem and 

 admiration, and affords a criterion of good and evil. 



There is here an attempt to unite a scientific 

 neutrality with a positive ethical construction. Pro- 

 gress is no increase in the net value of life ; it means 

 the impartial development of good and evil ; yet 

 progress must be our criterion of value and good. 

 One need only point to Mr. Bcnett's criticism of 

 hedonism, where he points out that just because 

 pleasure is an impartial stimulant of all sorts of action 

 it cannot be the criterion of good, to show the incon- 

 sistency of this position. To avoid the difficulty by 

 making progress represent only the positive aspect of 

 evolution is to fall on the other horn of the perpetual 

 dilemma of ethical construction, and make good the 

 criterion of good. -Apart from this defect of funda- 

 inental theory, Mr. Benett's book shows considerable 

 power of psychological analysis ; his treatment in the 

 later chapters of complex moral facts and concrete 

 virtues is often admirable. His argument is always 

 forceful, his style is powerful, and one feels through- 

 out the presence of a straightforward insistence that 

 we must face the facts as we find them of human 

 nature and the world. These are qualities which go 

 far towards a valuable re-handling of moral problems. 



The Poisonous Terrestrial Snakes of our British 

 Indian Dominions and how to recognise Them. By 

 Major F. Wall. Second edition. Pp. x + 6g; illus- 

 trated. (Bombay : Natural History Society, 1908.) 

 Price 2 rupees. 

 To those whose travels have never extended beyond 

 western Eurojje it is a difficult matter to realise 

 how largely poisonous snakes loom in the life of our 

 native fellow-subjects in India, or to appreciate the 

 heavy annual list of casualties due to snake-bite. To 

 mitigate the evil, the European and the native medical 

 staff of the country are now bringing into play the 

 latest remedies of their science, but they are frequently 



