494 SCIENCE PROGRESS 



A very brief introduction gives some account of the properties of the carbo- 

 hydrates, their chemistry is but touched upon, and more information on soki- 

 bilities, densities and other physical properties would have been useful. 

 Exception must be taken to the sweeping statement that the iodine reaction, 

 characteristic of all starches, is not produced by any other known substance, 

 as Barger some years ago obtained blue adsorption phenomena with a number 

 of crystalline organic compounds. 



The book is divided into six parts dealing with (i) Starch and its products, 

 (2) Sugar, (3) Beer, (4) Wine, (5) Distilled fermented liquors, (6) Vinegar. 

 There is some indication of a general plan in each section, but this has prob- 

 ably suffered as the result of collaboration. An historical sketch is followed 

 by some account of the natural sources of the various products and the 

 conditions of cultivation. Details of manufacture, the utilisation of waste 

 products and statistics of production are dealt with, and each part concludes 

 with a list of references to papers, articles and textbooks. Part II, dealing 

 with sugar, is the largest section, and contains a clear account of the culti- 

 vation of cane and beet and the various manufacturing processes by which 

 sugar is obtained from these sources. Among the fermentation products, 

 beer is given the pride of place and space ; a short section is devoted to the 

 problem of synthetic alcohol, now becoming so urgent in view of the fuel oil 

 shortage, and another to the fermentation processes for the manufacture of 

 acetone and of glycerine, which assumed great importance during the war, 

 owing to the lack of these compounds for the preparation of explosives. 



The facts are clearly presented, though occasionally there is slight care- 

 lessness of phraseology ; for example, on p. 195, confusion might arise between 

 methyl and ethyl alcohols. No attempt has been made to give a complete 

 account of the subject, but a general outline is supplied, which indicates some 

 of the difficulties of manufacture which have been overcome, and the problems 

 yet to be solved. The book would have been more valuable if the theoretical 

 side had been dealt with. The chemistry of the sugars, of the manufacturing 

 processes and of fermentation is barely mentioned, and the many problems 

 in physical chemistry which arise in the various processes are ignored. The 

 book is, however, welcome in that it may divert students of chemistry from 

 the ornamental but popular dye-stuffs to a more vital branch of industry in 

 which, in the future, chemistry will play an even greater part than it has in 

 the past. 



O. L. B. 



Chemical Fertilisers and Parasiticides. By S. Hoare Collins, M.Sc, F.I.C. 

 [Pp. xii + 273, with 8 figures.] (London : Balliere, Tindall & Cox, 

 1920. Price los. 6d. net.) 



This book is a companion volume to the author's Plant Products and Chemical 

 Fertilisers, and, like it, also belongs to the Industrial Chemistry series. Whereas 

 in the earlier volume the chemical fertilisers are only treated from the point 

 of view of crop increment, the present volume is devoted rather to the sources 

 and modes of manufacture of these same compounds. The book is divided 

 into six parts, entitled respectively " The Need for Fertilisers," " The Sources 

 of Fertilisers," " The Manufacture of Fertilisers," " The Use of Fertilisers," 

 " The Future of Fertilisers," and " Chemical Insecticides and Fungicides." 

 The mere recital of these headings, however, gives but a very inadequate 

 idea of the amount of interesting and out-of-the-way information contained 

 in this book. Very special attention is paid to the chemical processes and 

 principles involved in the manufacture of the fertilisers, and the author, 

 consequently, does not hesitate to draw upon the Phase Rule in describing 

 the manufacture of commercially pure potassium fertilisers from the naturally 

 occurring sources such as the double salts sylvine, kainite, carnallite, etc. 

 The utilisation of atmospheric nitrogen and the manufacture of inorganic 



