138 



NATURE 



[September 29, 192 1 



in its midst a high explosive, and a comparative 

 measure of the violence of ammonium nitrate 

 itself and of its mixtures w^ith trinitrotoluene was 

 quoted in a recent lecture to the Chemical Society. 

 The appearance of the crater formed in the Oppau 

 explosion is reminiscent of the effect of the de- 

 tonation of a large quantity of explosive, and the 

 result of the inquiry into the cause of the disaster 

 is awaited with much interest. The factory is in 

 the zone occupied by the French, and medical and 

 other assistance is being rendered by them and 

 by the other Allied troops on the Rhine. 



Applied Chemistry. 



(i) An Introd-uction to the Chemistrv of Plant 

 Products. Vol. I : On the Nature and Signifi- 

 cance of the Commoner Organic Compounds of 

 Plants. By Dr. P. Haas and T. G. Hill. 

 Third edition. Pp. xiii-f-414. (London: 

 Longmans, Green, and Co., 192 1.) 165. net. 



(2) Kieselsdure und Silicate. By H. le Chatelier. 

 Berechtigte Uebersetzung by Dr. H. Finkel- 

 stein. Pp. xi+458. . (Leipzig: Akademische 

 Verlagsgesellschaft m.b.H. : Gustav Fock, 

 1920.) 



(3) The Volatile Oils. By E. Gildemeister and 

 Fr. Hoffmann. Second edition by E. Gilde- 

 meister. Authorised translation by Edward 

 Kremers. Second volume. Pp. xx-|-686. 

 (London: Longmans, Green, and Co., 1920.) 

 325. net. 



(4) The Ftmdamental Processes of Dye Chemistry . 

 By Prof. H. E. Fierz-David. Translated by 

 Dr. F. A. Mason. Pp xiv4-24o-f- 19 plates. 

 (London: J. and A. Churchill, 1921.) 21s. net. 



(i) ly /r ESSRS. HAAS AND HILL'S " Chem- 

 iVJL istry of Plant Products " is now in 

 its third edition. As it has been reprinted, the 

 opportunity has been taken to rearrange the sub- 

 ject-matter and to devote more attention to 

 physiological problems. This has caused a con- 

 siderable enlargement of the work, which will now 

 appear in two volumes. The present volume — the 

 first of the series — deals primarilv with the 

 chemistry of the subject and, in the main, consists 

 of the chemical matter of the earlier editions, 

 revised and brought up to date, and to some 

 extent rewritten. It is arranged under ten sec- 

 tions, viz. : Fats, oils, and waxes, and phosphat- 

 ides ; aldehydes ; carbohydrates ; glucosides ; 

 tannins ; pigments ; nitrogen bases ; colloids ; pro- 

 teins ; and enzymes. Each section is largely sub- 

 divided, so as to make it as comprehensive as 

 possible. There is, of course, no necessary chemi- I 

 NO. 2709, VOL. 108] 



cal connection between the several sections. It is 

 probably impossible to devise a perfectly rational 

 scheme of classification, as in a well-ordered 

 treatise of chemistry, where the several parts are 

 knit together in more or less logical sequence. 

 The scheme adopted by the authors certainly 

 serves to bring together all the more important 

 facts connected with the chemistry of plants and 

 plant products, and with the aid of an excellent 

 index and an ample bibliography there should be 

 little difficulty in the search for information. 



The analytical section is one of the most com- 

 mendable features of the work. It has been care- 

 fully compiled, and the several methods are ade- 

 quately described. It is perhaps impossible now 

 to make the change, but honour is not given 

 wnere honour is due by ascribing to Fehling the 

 method of determining certain sugars by the 

 reduction of an alkaline tartrate solution of copper 

 sulphate. The real author of this method was the 

 French chemist Barreswil, and his name should 

 be given to it. The merit of the German chemist 

 consisted in studying the conditions under which 

 the method gave consistent and uniform results, 

 but he added no original feature to the process. 

 In consequence of the great development of the 

 sugar industry in Germany, Fehling's directions 

 were generally followed in that country, and his 

 name came to be associated thereby with the 

 method. Similar instances of misappropriation 

 are not unknown in German chemical literature. 



(2) Dr. Finkelstein's translation of le Chatelier's 

 admirable monograph, " La Silice et les 

 Silicates," was made during the winter of 

 1913-14 — that is, within a few months of the ap- 

 pearance of the French work — but its publication 

 has been delayed by the occurrence of the Great 

 War. The delay has, however, enabled the trans- 

 lator to include a certain amount of new matter 

 dealing w'ith refractories, and has thereby added 

 to the value of the treatise. Le Chatelier's work 

 on silicic acid and . its industrially important com- 

 pounds is unquestionably the most learned con- 

 tribution yet made to the literature of the sub- 

 ject. It is a model of what such a monograph 

 should be — excellently arranged, clear, concise 

 yet adequately full, and scrupulously accurate. 

 The compilation of such a work must have 

 required an enormous amount of research and 

 reading, in addition to an intimate personal 

 acquaintance with the subject based upon long- 

 continued original inquiry. Indeed, this note of 

 originality, obvious on almost every page, is one 

 of the most characteristic features of the book. It 

 is to be seen in the judicious and critical treatment 

 of the subject-matter, even when the author is 

 dealing with other men's work, all of which is 



