REVIEWS 489 



We do well, therefore, to read over again the foundations of classical 

 dynamics as here expounded, to ponder its limitations, and to beware lest, 

 in criticising the older schools of thought, we may be condemning ourselves. 



E. Cunningham. 



CHEMISTRY 



Qualitative Analysis in Theory and Practice. By P. W. Robertson, M.A., 

 Ph.D., Professor of Chemistry, Victoria University College, New 

 Zealand, and D. H. Burleigh, A.R.C.S., D.I.C., B.Sc. [Pp. 63, with 

 tables.] (London : Edward Arnold, 1920. Price 4s. 6d. net.) 



The present tendency is rather in the direction of giving up qualitative 

 analysis and " spotting " as a means of introduction to the technique of 

 practical chemistry. Prof. Robertson and Mr. Burleigh, however, hold the 

 view that qualitative analysis intelligently taught is of very great value in 

 forming a foundation for the general chemistry of the metals, and in illus- 

 trating the more important types of chemical reaction ; they regard the 

 practice followed by most textbooks of describing in detail the individual 

 reactions of the metals, and writing all the equations for these reactions, as 

 pernicious and demoralising, the student in the end simply copying into 

 his notes what he sees in the book. 



The method, therefore, which has been adopted is to make the student 

 aware of the kind of reaction to be expected in any given case — in other 

 words, they have endeavoured to eliminate the false antithesis between 

 theory and practice ; then, having learnt the different types of chemical 

 reaction, the student is able to see how they are applied to the problems 

 of systematic analysis. 



The weak point in the above argument is, of course, that it depends upon 

 the intelligent teaching of the subject — in other words, upon the active co- 

 operation between teacher and student — or else the whole procedure descends 

 - to the level of the teaching of Latin grammar, the sole virtue of which seems 

 to lie in the fact that it affords the maximum amount of pointless effort 

 on the part of the student, with the minimum degree of exertion on the part 

 of the teacher. 



Assuming, however, the correctness of the authors' views, the present 

 little book should be a very useful introduction to practical chemistry, and 

 the long experience of the two authors is a guarantee that the book has 

 been carefully thought out and put together. F. A. M. 



Quantitative Analysis by Electrolysis. By Alexander Classen and H. 

 Cloeren ; Revised, Rearranged, and Enlarged English Edition by 

 William T. Hall, Associate Professor, Massachusetts Institute of 

 Technology. [Pp. xiii + 346, with 2 plates and diagrams.] (London : 

 Chapman & Hall, 1920. Price 17s. 6d. net.) 



Classen's book on Electrochemical Analysis is too well known to need any 

 fresh introduction to English readers. The present edition is a revision of 

 the 191 3 edition without reference to the German text, so that it is in many 

 respects a new work. 



An attempt has been made to apply the modem electronic theory a 

 little more closely than has usually been the case with other works on the 

 subject, so as to assist the beginner to understand exactly what takes place 

 during electrolysis. 



The first part deals with the general laws governing the method and 

 with the types of apparatus needed. The second part covers the electro- 

 analytical determination of various metals, including those elements, such 

 as aluminium and the alkalies, which can only be deposited as amalgams ; 

 the third section includes the methods of electrochemical separation of 



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