REVIEWS 343 



but goes somewhat further. Its method is experimental, and intends that the 

 student should carry out a number of qualitative experiments as well as the usual 

 measurements. The author is one of those who believe that a beginner should be 

 introduced to the subject by means of electrokinetics rather than electrostatics. 

 This point of view is not novel, but in no other book of the same type (as far as 

 the writer is aware) has the author exhibited the courage of his convictions more 

 openly, or set about putting them into practice in a more thorough and painstaking 

 way. One novel point is the abandonment of primary batteries as the source of 

 current, and the use, instead, of continuous current lighting mains, in connection 

 with suitably wired "fool-proof" lamp-boards, which can be made with little cost. 

 That this method has everything to recommend it in the case of pupils who live 

 in modern towns, possessing electrical installations, goes without question. It will 

 evoke their eager interest at the outset, and will find many of them already 

 furnished with quite a fund of personal experience concerning the " mains " and 

 "volts" and "amps.," which, although confused and even erroneous, will form an 

 excellent foundation for further insight, and even for a rough illustration of the 

 scientific method in sorting and classifying essential facts. The book is clearly 

 written, well got up, and furnished with a large store of experimental work. One 

 notable point is the unity which is introduced into the teaching ; magnetism is 

 introduced by means of the electromagnet ; electrostatics is no longer a matter 

 of sealing-wax and cat's fur ; it falls into its natural place in the development of 

 the subject, and electrification by friction " is relegated to a subordinate place as 

 merely one method (although an important one) of producing electric charges." 



The book can be heartily recommended to every teacher ; it is, indeed, the 

 outcome of the author's own experience as a science master. Even those who 

 may disagree with his arrangement of the sections, or who may, through lack of 

 electrical installation, be unable to avail themselves of his methods, will find much 

 in the volume of which advantage can be taken. 



J. Rice. 



CHEMISTRY 



Volumetric Analysis. By A. J. Berry, M.A., Fellow of Downing College, 

 Cambridge. [Pp. viii + 138, with 7 diagrams.] (Cambridge : at the 

 University Press, 191 5. Price 6s. bd. net.) 



This volume, which appears in the publishers' well-known " Physical Series," 

 is designed to fill a place between elementary and advanced text-books on the 

 subject. The author has laid special stress on explaining the conceptions of 

 equivalent weights and normal solutions. How far he has succeeded in the 

 latter case is an open question. Junior students seem to have no difficulty in 

 grasping the significance of " normal " when applied to acid, alkali, and ordinary 

 salt solutions, but when they first make the acquaintance of, say, n/10 perman- 

 ganate, they naturally apply to it the rules which have enabled them to arrive 

 at values for these former solutions. 



No matter how they have been taught the meaning of " normal " solutions, 

 students seldom realise the full significance of the term until they encounter 

 permanganate or similar oxidising solutions. The term n/10 permanganate, 

 when the solution is to be used as an oxidising agant, is obviously a misnomer. 

 It is only really correct to speak of n/10 " available oxygen solution (via per- 

 manganate)," and if this terminology were strictly adhered to, in the case of 

 unior students, the difficulties now experienced would be largely minimised. 



