REVIEWS 497 



mind the general underlying theories which he has already mastered and soon 

 orientates himself anew." 



Allowing for the German scientist's natural bias, there was possibly something 

 to be said for his point of view, though it is doubtful whether he would venture on 

 quite the same opinion at the present day. 



In any case, whether the practical dyer nowadays deserves Ostwald's sweeping 

 condemnation or not, he can certainly profit much by a perusal of the volume 

 under review. Mr. Whittaker's position as head of the experimental dye-house of 

 British Dyes, Ltd., is sufficient guarantee of the accuracy of the book, and anyone 

 whose business or profession requires him to deal with dyes or dyed materials will 

 find much to interest and instruct him in its pages. 



The book has been written with a view to giving the reader a firm grasp of 

 the chemical principles involved and the methods used in the application of the 

 coal-tar colours. 



Perhaps one might wish that a little more attention had been devoted to the 

 theory of the subject, but no doubt the author has purposely refrained from 

 overloading the book with theoretical matter, holding, perhaps, that an ounce of 

 fact is worth a pound of theory. 



(2) Electrometallurgy: Electrolytic and Electrothermal Processes. By 

 Eric K. RlDEAL, M.A., Ph.D., F.I.C. [Pp. xii + 247, with 26 figures in 

 the text.] (Price 7s. 6d. net.) 



The recent Government Report on Electric Power Supply in Great Britain must 

 have made many people realise on the one hand how very wasteful and un- 

 economical much of our power supply is, and on the other the enormous 

 potentialities which lie before a really cheap and efficient s^tem. 



There is no doubt whatever that the near future will see very great develop- 

 ments indeed in electrochemical industries if only the cost of the power can be 

 made low enough. The refining of metals, the manufacture of steels and other 

 alloys, the production of fertilizers, explosives, acetic acid, alcohol and abrasives, 

 to mention only a few examples, will all be carried out by electrolytic or electro- 

 thermal processes. For this reason Dr. Rideal's book has appeared at an 

 opportune moment, and should serve admirably either as an introduction to the 

 subject of technical electrochemistry, or as a revision course for those who wish to 

 keep au courant with the subject, and have neither time nor inclination to read 

 all the technical journals. 



The following summary of the section headings will indicate the scope of the 

 book : Electrolysis in Aqueous Solutions and in Fused Electrolytes ; Electrolytic 

 Preparation of the Rarer Metals ; Electrothermal Processes ; Carborundum and 

 Oxysilicides of Carbon ; the Carbides ; Electrothermal Nitrogen Fixation ; and 

 Iron and the Ferro-alloys. On page 237 a useful reference list is given showing 

 some of the electrolytic properties of the elements. 



One could wish that some figures of the actual costs of the various processes 

 were given, as, after all, in the strenuous reconstruction period which will face us 

 after the war, the competition will be of the keenest, and only the most efficient 

 and economical processes will be able to hold their own. 



The text is illustrated by a number of clear diagrams, and for those seeking 

 further information there is a useful bibliography at the end of each section, so 

 that the book should prove of use to a wide circle of readers. 



F. A. M. 



