September 8, 192 1] 



NATURE 



Zfi 



Arab influence, from the beginning of the tenth 

 to the latter part of the twelfth century ; and three 

 centuries of the Scholastics form the last division. 

 The salient characteristics of each division and the 

 leading figures are clearly brought out. Specially 

 notable is the lively picture of the travelling 

 scholar from the West who gets in touch with 

 Arab learning through some Jewish interpreter 

 in a back street of Toledo ; and on the side of 

 theory due emphasis is laid on the cardinal doc- 

 ^ trine of medieval science, the correlation of the 

 macrocosm and the microcosm, and the enforce- 

 ment of this by Arabian astrology. 



The whole essay is valuable and deserves care- 

 ful study. The original scientific work of Albertus 

 Magnus receives full credit, though Stadler's new 

 text of one work, the "De Animalibus," was still 

 inaccessible when the book was published. There 

 is an excellent short summary of Roger Bacon's 

 achievements, and Nicolas of Cusa (1401—64) is 

 recorded as the first biological experimenter of 

 modern times, Helmont's experiment on a grow- 

 ing plant, showing that it absorbs something of 

 weight from the air, being due to him. 



If we must record a difference from Dr. Singer, 

 it is one of emphasis rather than one of opinion 

 or of fact. He appears to us to exaggerate some- 

 what the breach with the classical past which the 

 new thought at the end of the medieval period 

 involves. The difference is due mainly to the fact 

 that as a biologist he is struck more by the mass 

 of new and accurate observation which the modern 

 biologist introduced, and less by the continuity of 

 abstract reasoning which mathematical and astro- 

 nomical science inherited from the Greeks. 



Plantation Rubber Research. 

 Plantation Rubber and the Testing of Rubber. 

 By Dr. G. Stafford Whitby. (Monographs on 

 Industrial Chemistn.-.) Pp. xvi + 5594-8 



plates. (London: Longmans, Green, and Co., 

 1920.) 285. net. 



THE general editor of this well-known series 

 refers in his introduction to the extra- 

 ordinary development which the applications of 

 chemistry have experienced during the last four 

 or five decades. In the case of the rubber indus- 

 try the development is even more recent. Prac- 

 tically the whole of the facts dealt with in Prof. 

 Whitby's book have been discovered within the 

 last fifteen years, and with few exceptions the 

 application of a knowledge of the chemistry of 

 rubber to the industry may also be said to date 

 from the introduction of plantation rubber. Pre- 

 vious to 1905 publications dealing with rubber 

 NO. 2706, VOL. 108] 



were few and far between. With one outstand- 

 ing exception, namely, C. O. Weber's "Chemistry 

 of India Rubber " (1902), there was no text-book 

 dealing with the subject from a theoretical or 

 scientific point of view. The student at that time 

 could make himself familiar with practically all 

 that was either known or surmised by a study of 

 Weber's treatise, and although many of the 

 ingenious suggestions put forward by Weber have 

 had to be abandoned, the book is one that can 

 still be read with profit. 



With the inception and development of planta- 

 tion rubber several chemists began to take an 

 interest in the study of this material, and from 

 time to time other text-books have appeared. 

 Whereas Weber was able to coyer the whole field, 

 including manufacturing technique and chemical 

 analysis, in three hundred pages, many later 

 authors have restricted themselves to special 

 branches of the subject. Prof. Whitby has done 

 this, and although he has dealt neither with manu- 

 facturing technique nor with analysis, his book 

 runs to some five hundred pages. The title, if 

 cumbersome, is certainly descriptive of the con- 

 tents, and the book falls naturally into two parts, 

 the first dealing with the preparation and proper- 

 ties of plantation rubber and the second with the 

 physical properties of vulcanised rubber and the 

 interpretation of results obtained in terms of 

 " quality." The first section presents an exact 

 and up-to-date account of the facts and theories 

 underlying the preparation of plantation rubber 

 and a description of the technique as at present 

 in vogue on the best plantations in the East. 

 Such a task could be attempted only by one who 

 has actually carried out experimental work on a 

 plantation and controlled the preparation of 

 rubber. Prof. Whitby had unique opportunities 

 for observation and research, and he has made 

 the most of them. Coming home after some years 

 in the East, he has been able to follow up his 

 plantation work with laboratory studies particu- 

 larly directed to vulcanisation problems and theii 

 elucidation. Consequently the second part of the 

 book presents as thorough and complete a review 

 of the subject as the first. 



In the early days of plantation rubber the 

 planter naturally looked to the rubber manufac- 

 turer at home for information and advice as to 

 the best form in which to market his product. 

 But the majority of manufacturers did little 

 beyond pointing out that " fine hard Para " was 

 the best rubber, and should form the ideal of the 

 planter's aims. The tedious and primitive pro- 

 cess of the Amazon, however, was not suited to 

 plantation requirements; so, having tested vari- 



