39- 



AM TURE 



[September 30, 1909 



of the necessary small scale, are perfectly clear and 

 distinct in all the essential details. The stresses in, 

 and the design of, solid masonry arches and culverts 

 form the subject of two chapters, and, though there 

 is nothing specially novel in the treatment adopted, 

 these sections of the book will be welcome to the 

 draughtsman who is engaged in this branch of bridge 

 design, especially as the author has given some useful 

 notes on the theory of reinforced concrete. 



In part iii. of the book there is a full critical investi- 

 gation of an existing structure— the weights, costs, 

 and efficiencies of the members of a Pratt highway 

 bridge of i6o feet span are fully worked out, and 

 the errors in design pointed out, and the modifications 

 which would improve the design are suggested. There 

 is no doubt that such an investigation is bound to 

 make students familiar with bridge details, and we 

 would commend this method to the notice of engineer- 

 ing teachers. X. H. B. 



OUR BOOK SHELF. 

 Die Strahlen der positiven ElektrizHdt. By Prof E. 



Gehrcke. Pp. .xi+124. (Leipzig: S. Hifzel, 1909.I 



Price 4.50 marks. 

 At a moment when scientific thought is being con- 

 centrated on the consideration of the nature of posi- 

 tive electricity, we can only welcome the appearance of 

 a book which aims at bringing together, in the short 

 compass of a hundred pages, all the principal facts 

 bearmg on the subject. This Prof. Gehrcke has done, 

 and he has done it well, for, with the e.xception of 

 a few shght omissions, he has put before his reader 

 all that is essential with regard to positive rays. 

 But we could wish that more than this had been 

 done, for it is a little disappointing to find the results 

 of experiments given, often with little, if anything, to 

 indicate the theoretical deductions which can'be drawn 

 ^t°'?- "''^"^- Indeed, not infrequently the opinions 

 of different investigators as to the interpretation of 

 the results of experiments are recorded without any 

 comment as to the relative merits of rival theories. 

 No doubt it was the intention of the author to keep 

 the work within definite limits, but it seems that 

 much has been sacrificed merely for the sake of 

 brevity. In no part of the book is this more appar- 

 ent than in the portion devoted to radio-activity and 

 the nature of the a rays. Here descriptions are' often 

 so short that it is questionable whether anyone not 

 already fully acquainted with the subject will be able 

 to follow the reasoning. 



In the part dealing with radio-activity there are a 

 few inaccuracies which call for comment. On p. 90 

 the author states that it is usually supposed that 

 one a particle is given off from each atom during any 

 radio-active process involving the emission of such 

 particles. In view of the work of Bronson, who 

 showed, for example, that an atom of thorium 

 emanation, in breaking up, gives off four times as 

 many a particles as an atom of thorium B or C, this 

 is clearly not the case. Again, the table on p. 8g 

 contains some mistakes. The volatilisation point of 

 radium A, given as 1000° C, is too high, and that 

 of radium C, as 1100° C., is too low. The volatilisa- 

 tion point of radium B is given as 20° C., instead 

 of 600° C. That radium B can escape, at ordinary 

 temperatures, from a surface coated with active 

 deposit is correct, but the phenomenon is not due to 

 any true volatility of the substance at ordinary tem- 

 peratures, and has been explained on quite different 

 lines. 



NO. 2083, VOL. 81] 



Das Seelenlehen der Tierc. By Dr. P. Ohm. Pp. 117. 



(Stuttgart : Neue Weltanschauung, 1909.) 

 This little book is the fourth of a series called 

 " Weltanschauungs-Frag'en," and apparently intended 

 to include contributions to the monistic philosophy 

 of Haeckel. Consequently, Dr. Ohm brings forward 

 the two principal theories of animal intelligence — one 

 that it is totally different in kind from human, and 

 the other that it is tlie product of evolution, and 

 differs only in degree, but is essentially of the same 

 nature. After a brief historical introduction to the 

 subject, and noticing the opinions held by various 

 authors from Plato to Wasmann, Darwin, and 

 Harold Holding, Dr. Ohm speaks of the dawning 

 intelligence indicated in Protista, sponges. Medusa, 

 Hydra, molluscs, &c., and then inserts a chapter on 

 instinct to controvert the view advocated by Was- 

 mann that it is a perfect and divine inspiration, quite 

 different from reason. Here he deals especially with 

 the manifestations and imperfections of the intelli- 

 gence of insects, especially ants and bees. 



Another chapter is devoted to the " Seelenleben " 

 (" soul-life," or, more correctly, intelligence) of 

 insects and spiders, with special reference to their 

 eyes, antennae, sense of direction, &c., and a figure 

 is given of the Indian tree-ant (CEcophyUa smarag- 

 dina) using one of its own larvae to spin threads. 

 An illustration is also given of the large garden 

 diadem spider and its web. .Another chapter follows, 

 on the senses, habits, and intelligence of vertebrate 

 animals, and the book concludes with a comparison 

 between human and animal intelligence; and the 

 author regards the faculty of speech as the essential 

 difference between them. A short bibliography is 

 appended. 



Dr. Ohm has written a thoughtful little book, and 

 has dealt with a difficult subject fairly and moder- 

 ately. His work will be read with interest by 

 students interested in the important questions with 

 which it deals; but everyone is so much influenced 

 by preconceived ideas, on one side or another, that 

 it is almost impossible to form an unbiassed opinion 

 about them. W. F. K. 



Comment Former uii Esprit. By Dr. Toulouse. 



Deuxieme Edition. Pp. x-l-260. (Paris : Librairie 



Hachette et Cie., igoS.) 

 This book is the reply to a request for ten lessons, 

 to professional teachers and parents which should em- 

 body what Dr. Toulouse's experience as a psychologist 

 and a medical man lias taught him to think essential 

 to "the cultivation of an intelligence." He starts 

 from a position with which critics of educational in- 

 stitutions on this side of the Channel have made us 

 familiar; "we teach everything in school to-day 

 except how to think .-ind how to act." His remedy is- 

 also familiar — education should aim at teaching us 

 not so much to know as how to apply knowledge to 

 the regulation of the important affairs of life. To ■ 

 achieve this end it must train us, in accordance with f 

 sound principles of "method " (in the Cartesian 

 sense), to observe, to judge, to feel, to act. The 

 author's discussion of these methodical principles is 

 broad-minded and suggestive, but it is too brief and 

 schematic to be of much direct service to the teacher 

 in the class-room or the parent in the home. His 

 recommendations have much more value when they 

 either express the practical wisdom of a man who has 

 managed his life successfully or deal with specific i, 

 topics on which his experience as a medical psycho- | 

 logist gives him authority. Under the latter heading ' ' 

 attention may be directed to a vigorous argument for 

 the frank instruction of boys and girls in " the 

 phenomena of life." 



