REVIEWS 665 



the preparation of two of its derivatives ; and so with the other groups of 

 compounds such as proteins and pigments, several rather out of the ordinary- 

 preparations will be found here. The book has, however, to some extent 

 " le defaut de ses qualites " inasmuch as a good many of the more famihar 

 though none the less important facts have of necessity been omitted, and it is 

 difficult to avoid the impression that the book may perhaps be of more use 

 to the teacher than to the student. Part II is devoted to a study of enzymes, 

 microbiology, and fermentations, and Ukewise contains many instructive and 

 original experiments. 



It is to be regretted that the revision of the translation was not more 

 thorough, for such terms as iodhydrate of choline iodide, cadmium xylono- 

 bromide, iodine index, etc., grate on the ears of a chemist, while the inclusion 

 of oxalic, succinic, lactic, malic, tartaric, and citric acids under the heading 

 of " acids of the fatty series " is distinctly misleading. Moreover, the amount 

 of caustic potash required for making a normal solution of alcoholic potash is 

 given on page 181 as 70 grams, while a decimal point has been omitted in the 

 figure for a N/5 solution of sodium thiosulphate on page 132 ! 



P. H. 



Third Report on Colloid Chemistry, published on behalf of the Department 

 of Scientific and Industrial Research for the British Association for 

 the Advancement of Science. [Pp. 154.] (London: H.M. Stationery 

 Of&ce, 1920. Price 2s. 6i. net.) 



Following the plan adopted in the two preceding reports, the subject 

 matter is arranged under two heads, viz : (i) Classification according to 

 scientific subject, and (2) classification according to industrial process. The 

 subjects dealt with are CoUoid Chemistry of Soap, Ultra-microscopy, Electrical 

 Charges in Colloids, Solubihty of Gases in Colloidal Solutions, Imbibation of 

 Gas, Colloid Problems in Bread-making, Colloid Chemistry in Photography, 

 Collodion in Photography, Cellulose Esters, Colloid Chemistry of Petroleum, 

 Asphalt, Varnishes, Paints, and Pigments, Clays and Clay Products. 



P. H. 



The Manufacture o£ Sugar from the Cane and Beet. By T. H. P. Heriot, 

 F.I.C. [Pp. X -f 426, with illustrations.] (London: Longmans, Green 

 & Co., 1920. Price 24s. net.) 



The author of this monograph is to be congratulated on having produced a 

 book with just that blending of theory with practice which will enable the 

 general reader to acquire a very excellent all-round acquaintance with the 

 subject of sugar production. As stated in the Introduction, detailed de- 

 scription of sugar machinery have been omitted, and this wiU enhance the 

 value of the book to the general reader, since there are aheady a number of 

 books devoted to the detailed structure of sugar manufacturing plant. We 

 know of no other book of corresponding size written and produced in this 

 country which deals with the manufacture of sugar both from the cane and 

 from the beet, and the appearance of such a book should be welcomed at this 

 time when there is a revival of interest in the production of cane sugar 

 within the Empire, and of beet sugar in this country. The two industries 

 are in this book treated in separate parts or chapters, enabhng the reader, 

 if he so wishes, to follow the consecutive operations in one industry. Part I, 

 entitled Raw Materials, is divided into four chapters, of which the first is devoted 

 to the morphology of the cane and the beet and the physiology of sugar pro- 

 duction within them ; chapters ii and iii deal with the sugar-beet and sugar- 

 cane respectively from the point of view of their reproduction and contain a 

 brief account of the methods employed in producing beet-seeds ; chapter iv 

 is devoted to a brief review of other sugar-producing plants. The remaining 



