July i6, 1908] 



NA TURE 



-^A% 



reason, as well as for the clear statement ot some of 

 the educational problems involved, those interested in 

 educational progress will give the volume a cordial 

 welcome. At the same time, it seems a little doubtful 

 whether such facts should be published as that not 

 only the mental achievements, but the " nature, in- 

 stincts, experience, and ideals " of each child are noted 

 and tabulated by the students in training. The files 

 are no doubt kept with scrupulous privacy under lock 

 and key. But if through parents buying the book 

 and leaving it about, or talking about it, the children 

 get to know of this dissection, the injury to character 

 might be serious. 



The general scheme of the school work will have the 

 full approval of modern educationists, who will envy 

 Prof. Findlay and his colleagues the opportunity of 

 putting their theories into practice. Particularly valu- 

 able are Prof. Findlay's observations on the relation 

 of the school to civic and corporate life, and especially 

 his conviction that the parents are to be brought into 

 the closest possible touch with the educational as well 

 as the social aspects of the school work. It is indeed 

 onlv when we have educated the parents that we can 

 hope to have the full measure of success in educating 

 the children. 



.As to details, the scheme of science teaching seems 

 excellently conceived. That of French shows careful 

 work in accordance with the direct method, the 

 psychology of which is so well explained by Prof. 

 Findlay's paper (reproduced p. 6g). It is to be hoped 

 that in future issues the relation of practice to 

 theory will be dwelt on ; for instance, one wants to 

 know ho-d} " the general efficiency of the school in 

 otiicr departments affects vitally the success or 

 failure " of the French teaching (p. 71). The scheme 

 for history and handwork combined has at least the 

 merit of boldness. With the object of increasing the 

 sympathy with social rather than personal interests, 

 biography has been discarded, and interest in the 

 material world takes its place until the children 

 are nine years old. From six to seven some ele- 

 mentary facts about the food, clothing, housing, 

 &c., of present-day life are taught, with practical 

 applications. From seven to nine the children are 

 " prepared for more systematic study of the his- 

 torical beginnings of the nation to which they belong " 

 bv being made to imagine themselves first as Tree- 

 people, then as Cave-dwellers, then as Red Indians, 

 then as pastoral tribes, and lastly as Saxons, and there 

 is plenty of scope for handwork in reproducing the 

 material conditions of the life of the different periods. 

 Then, judging from the record, it would seem that 

 at nine they are plunged straight into the details of 

 the history and literature of the period from 1625-1660. 

 For 1908 this was apparently the course for nil children 

 from nine to fourteen years of age. 



The chapter on the social aspects of child study is 

 not convincing, and scarcely seems to have been 

 written in such close contact with the life of the school 

 as the others. It shows a tendency to vague language 

 and uncertain generalisations which seem out of place 

 in the record of a demonstration school. 



It is legitimate to hope that the future volumes 

 will answer more of the questions they raise. 



NO. 2020, VOL. 78] 



ELEMENTAR Y ELECTRICITY. 

 An Introduction to Electricity. Being a translation of 

 the second edition of " Einfuhrung in die Elektrizi- 

 tatslehre," with corrections and additions by author. 

 By Bruno Kolbe. Translated by Joseph Skelton. 

 Pp. xii+430. (London: Kegan Paul, Trench, 

 Triibner and Co., Ltd., igoS.) Price 10s. 6d. net. 



THE editor offers this volume as a satisfactory 

 introduction to the science, both for students 

 and for "the man in the street." So far as the 

 former is concerned, the claim may be dismissed at 

 once; the book is too inaccurate; and the "man in 

 the street " must have a remarkable mind if he gets 

 what he wants from Prof. Kolbe. We should have 

 imagined that he required a clear statement of prin- 

 ciples, and was not greatly concerned with experi- 

 mental evidence. Prof. Kolbe gives him an over- 

 whelming mass of experiment — (it is only fair to say 

 that the experiments are often highly ingenious) — • 

 accompanied by confusing and misleading deductions. 



Comprehension is rendered more difficult by the 

 failure of the translator to eliminate the syntax of the 

 original. We may be misrepresenting the author, 

 but the following argument appears to be a simplified 

 form of his treatment of the fundamental conceptions, 

 charge, potential and capacity. L^nit charge is de- 

 fined as that on a certain proof ball after contact with 

 a certain conductor charged to its spark potential. 

 Successive charges are communicated to an electro- 

 scope, and a scale defining the magnitude of charges 

 is graduated. The electroscope is then connected by 

 a wire to various points of a charged conductor; the 

 constant reading is defined as the " degree of electrifi- 

 cation " (potential) of the conductor. It will be noted 

 that in order that these definitions may agree with 

 those used in stating the fundamental theorems, the 

 capacity of the electroscope must be infinite in -com- 

 parison with that of the proof ball, and infinitesimal 

 in comparison with that of any conductor of which 

 the potential is'to be measured. After a long digres- 

 sion we come to capacity, for which two electro- 

 scopes measuring potential are required. The author 

 appears to graduate the scales as before, and to 

 assume that similar readings denote similar " de- 

 grees of electrification"; of course they will do so 

 only if the capacities of the electroscopes are the same. 

 After another chapter and a half we find the ordinary 

 definitions of charge and potential; the former is 

 shown experimentally to agree with that adopted pre- 

 viously (experimental complications are unknown to 

 the 'fortunate author); but though the quantitative 

 agreement of the latter with " degree of electrifi- 

 cation " is asserted and assumed subsequently, no 

 attempt is made to prove it. No indication is given 

 of the connection of potential with field strength. In 

 rejecting symbols. Prof. Kolbe appears to have re- 

 jected the whole of the logic of which those symbols 

 are the ordinary expression. 



Two glaring blunders should be noted in the same 

 part of the book. The author tries to prove that there 

 can be no charge inside a solid conductor without 

 assuming the inverse square law ; of course the proof 

 is fallacious. He also states that the action of a flame 



