54 8 SCIENCE PROGRESS 



mcnt that during the process of distilling over the ammonia into the standard acid 

 the caustic alkali should be added from time to time is of course ridiculous. 



The style throughout the book is extraordinary. What, for example, is to be 

 said of the statement, " In such cases it is necessary to put on a blank," by which 

 is presumably meant that a control experiment should be performed ? A good 

 many references to original papers are given, but although a list of abbreviations 

 is given the abbreviations actually employed in the text rarely coincide with those 

 given in the list, and several journals are quoted which find no mention in the list ; 

 moreover, there is a complete lack of system about the quotation of dates ; some- 

 times they appear before the volume and page and sometimes after, but as often 

 as not they do not appear at all. 



The Raw Materials for the Enamel Industry. By Julius Grunwald, 

 Dr.Ing. Translated by H. H. HODGSON, M.A., B.Sc, Ph.D. With 

 21 Illustrations. [Pp. viii + 225.] (London: Charles Griffin & Co., 1914. 

 Price Ss. 6d. net.) 



The production of enamelled utensils made of cast and sheet iron forms a sort 

 of connecting link between the ceramic and iron trades. The art of enamelling 

 is of great antiquity, but its application in the industrial, as distinct from the 

 artistic, world is quite modern, and has become important only during the last 

 fifteen years. There are now, or were before the war, over forty thousand persons 

 employed in Germany and Austria in enamelling iron objects, and possibly one 

 or two thousand in this country. The importations from Germany are very large. 

 The industry is therefore one to which attention may well be directed at the 

 present time, and the appearance of this book is timely in the highest degree. 

 It completes Dr. Griinwald's trilogy on the subject, the other two translations 

 being Enamelling on Iron and Steel and The Technology of Iron Enamelling 

 and Tinning. Dr. Grunwald is one of the foremost experts in enamelling 

 technology. 



The significance of the recent change in the industries in Germany, from 

 the period when old empirical methods were employed to that in which the 

 operations are conducted by scientifically trained men, is typified in enamelling. 

 It is already clear that a similar change is taking place in this country, and 

 the improvement in technical literature is one of the signs of the change. The 

 present book is an excellent example of what is required. It gives a clear and 

 detailed account of each of the new materials used — over twenty in number — its 

 composition, preparation for use, and source of supply. The difficulties caused 

 by variations in the chemical composition or physical condition of the constituents 

 of enamel are discussed and remedies given. The author, however, admits that 

 many problems concerning enamel manufacture still await solution. 



The book will be useful not to enamelling works alone. It will also be a 

 handy book of reference in the ceramic industries, in which the same raw 

 materials are used with few exceptions. The translation appears to be a good 

 one, and the book is well printed and easy to read. 



T. K. Rose. 



The Metallurgy of the Non-Ferrous Metals. By William Gowland, F.R.S., 

 A.R.S.M., M.I.M.M., etc. With 195 illustrations. [Pp. xxvii + 496.] 

 (London : Charles Griffin & Co., 1914. Price i8j. net.) 



Metallurgical literature is enriched by the publication of this excellent text-book, 

 the product of the long experience and ripe judgment of a man who may justly be 



