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NATURE 



[February i8, 19 15 



same time the remaining sections of the work 

 have been revised by British authorities, and, 

 wherever necessary, modified in the same sense. 

 In addition, each section has been brought up to 

 date by the inclusion of all relevant matter of 

 importance. 



The sections on mineral-oils, lubricants, oils, 

 fats, and waxes, and the special methods of 

 analysis employed in the oil and fat industries 

 were contributed or revised by the late Dr. Lew- 

 kowitsch — an acknowledged authority on this 

 class of subjects. Dr. Lewkowitsch also revised 

 the English translation of Dr. Dieterich's article 

 on resins, balsams, and gum-resins. The same 

 author's article on drugs and galenical prepara- 

 tions has been revised by Dr. Power, who has also 

 taken charge of Dr. Gildemeister's contribution 

 on essential oils. The sections on tartaric and citric 

 acids have been entrusted to Mr. Davis, whilst 

 the general subject of organic preparations — a 

 somewhat vague class — has been dealt with by the 

 Editor. This section is concerned more particu- 

 larly, although by no means exclusively, with 

 pharmaceutical preparations, and is based upon an 

 article by Dr. Messner of the firm of Merck and 

 Co., of Darmstadt. The important section on 

 rubber has been revised by Dr. Caspari, who, 

 however, has nothing to say concerning synthetic 

 rubber, from which we may infer how small has 

 been the influence of the " boom " on " artificial 

 rubber " on the actual production of this sub- 

 stance. 



Vegetable tanning materials and leather have 

 been revised by Prof. Procter, an acknowledged 

 authority on the scientific aspects of tanning ; 

 whilst sugar, starch, and dextrin have been dealt 

 with by Mr. Arthur R. Ling — no less an authority 

 on these particular subjects — who has also re- 

 written, in conjunction with Mr. Cecil Jones, a 

 valuable article on brewmg materials and beer. 

 Paper has received the attention of Messrs. Cross, 

 Bevan and Bacon ; textile fibres that of Prof. 

 Hiibner, of the Manchester School of Technology ; 

 while Messrs. Rawlins and Rule have revised 

 Prof. Eibner's article on inorganic colours. It 

 will be seen, therefore, from this list of names 

 that Dr. Keane has spared no pains in securing 

 the collaboration of competent authorities on 

 chemical analysis as applied to technical products 

 and processes. 



The book, like its predecessors, should find a 

 place in the library of every consulting and 

 analytical chemist, as well as in that of every well- 

 equipped works laboratory. A very commendable 

 feature of the work is the admirable bibliography 

 which accompanies each article. 



Another feature, even more valuable, is seen in 

 NO. 2364, VOL. 94] 



the extent to which individual revisers have 

 brought their special experience to bear upon the 

 sections entrusted to them, thereby greatly en- 

 I hancing their merit. This makes the English 

 edition of the work doubly valuable, as compared 

 with the German original, since each article has 

 passed, so to say, twice through the refining fire 

 of expert assayers. 



(2) Prof. Lunge's book on technical gas 

 analysis is in a sense the third edition of his well- 

 known handbook of technical gas analysis, origin- 

 ally based upon the late Prof. Clemens Winkler's 

 "Anleitung zur chemischen L'ntersuchung der 

 Industrie-Gase." During the dozen years which 

 have elapsed since the publication of the second 

 edition of the handbook the subject has received 

 an extraordinary development, and great changes 

 have occurred in procedure and apparatus. The 

 application of technical gas analysis has been 

 largely extended, and its value as an analytical 

 agent in industrial processes, and even in con- 

 nection with hygiene, has been widely recognised. 

 Hence the time had arrived when the compara- 

 tively narrow limitations of Clemens Winkler's 

 treatise had to be discarded, and the book under 

 review is, therefore, practically a new work, differ- 

 ing wholly in groundwork and arrangement from 

 that on which it was originally based. So far as 

 we have been able to discover, all branches of the 

 subject have received adequate treatment. The 

 bibliographical references are copious and up-to- 

 date. Lastly, the book is well printed, excellently 

 illustrated, and the indexes of authors' names and 

 of subjects are remarkably full. T. 



TWO BOOKS ON THE EARTH. 

 (i) Geology of To-day. A Popular Introduction 



in Simple- Language. By Prof. J. W. Gregory. 



Pp. 328. (London : Seeley, Service and Co., 



Ltd., 1915.) Price 55. net. 

 (2) College Physiography. By Prof. R. S. Tarr. 



Published under the editorial direction of Prof. 



L. Martin. Pp. xxii + 837. (New York: The 



Macmillan Co.; London: Macmillan and Co., 



Ltd., 1914.) Price 15^. net. 



THESE two books are professedly written 

 for two different types of reader ; but the 

 college student may well read Prof. Gregory's 

 " popular introduction " from end to end, while 

 the lover of " simple language " will find nothing 

 to alarm him in the work of the late Prof. Tarr. 

 (i) Prof. Gregory has brought the latest results 

 and the current discussions of geologists before 

 every thoughtful person to whom the earth 

 appeals. We possess a number of popular text- 

 books on geology, but " Geology of To-day " justi- 



