2,96 



NA TURE 



[January 30, 1908 



IHE PRODUCTION AND MANIPULATION OF 

 INDIA-RUBBER.' 



IX this work the author gives a description of the 

 various stages through which india-rubber passes 

 from the time when it oozes out of the tree until it 

 leaves the factory, a finished article, fashioned and 

 fit for the service of man. The boolv is expressly 

 designed for the general reader. It does not, except 

 incidentally, deal with the chemistry of india-rubber, 

 nor with the minute details of manufacture; the 

 volume is neither a laboratory guide nor a factorv 

 handbook. There are, however, many people in- 

 terested in india-rubber who are neither chemists nor 

 manufacturers, and the author thinks that a volume 

 conceived on broad general lines to expound the 

 natural and commercial history of rubber cannot be 

 deemed a superfluity. Similarly it may, perhaps, not 

 be amiss to give here a short outline of the matter 

 for the benefit of those readers of Nature who, like- 

 wise, are neither chemists nor manufacturers. 



Many species of plants are now known to vield 

 marketable rubber. They range from the lofty Hevca 

 hiaziliensis of the .Amazon swamps to the Landolphia 



creepers of West Africa and the Clitandra shrubs, a 

 foot or tw'o high, the rhizomes of which yield the " root- 

 rubber " of the Congo. The chief genera are Hevea, 

 Manihot, and Micranda (EuphorbiaceEe) ; Castilloa 

 and Ficus (.'\rtocarpaceaB) ; Hancornia, Funtumia, and 

 Landolphia (Apocynaceae) ; and Callotropis (Ascle- 

 piadeae). The bark of the trees yields a milky latex, 

 which is obtained generally by "tapping," though 

 sometimes by the wasteful process of felling the tree. 

 In various ways the latex can be caused to coagulate, 

 much as ordinary milk is made to " curdle "; and the 

 separated coagulum, after undergoing a process of 

 " curing," is the " raw " rubber of commerce. This 

 raw rubber, which comes here in various forms — 

 loaves, biscuits, balls, cups, sheets, lumps, and slabs 

 ^contains water, sand, woody fibre, and other im- 

 purities, ranging in quantity from 15 to 50 per cent., 

 which are removed by washing and rolling ; and there 



1 " India-Rubber and its Manufacture 

 and Balata." By Hubert L. Terry. Pp. 

 and Co., Ltd., 1907.) Price 6s. net. 



NO. 1996, VOL 77] 



with Chanters i 

 c + 294. (Londoi 



are also present resinous bodies, relatively small in 

 amount, but important in their effect upon the quality 

 of the rubber, that arc not eliminated by washing. 

 The cleaned rubber is " compounded " where neces- 

 sary {i.e. having regard to the purpose it is destined 

 to serve) by kneading it with various mineral in- 

 gredients, such as antimony sulphide, iron oxide, 

 litharge, and barium sulphate, and is eventually vul- 

 canised by treatment with sulphur before it emerges 

 in its final form as motor-tyre, cable, or other 

 article. 



Mr. Terry writes on these subjects with the autho- 

 rity of personal knowledge, though perhaps without 

 the lightness of touch desirable in a work of this 

 character. Probably the second and fifth chapters of 

 the book will be found of the most general interest. 

 They treat respectively of " the production of raw 

 rubber" and of "india-rubber plantations," giving 

 as fully as the scope of the work allows a sketch of 

 the present aspect of these matters. 



Among points mentioned as calling for special atten- 

 tion, it is urged that more care should be given to 

 the " tapping " operations, so that other juices nt 

 the trees shall not be allowed to mix with the rubber 

 latex. Further, the exudations of other 

 trees are sometimes mixed with the rubber 

 latex for the purpose of increasing the bulk. 

 The author mildly stigmatises this as an 

 " injudicious " practice; it is surely a fraud. 

 .\nother important point to which the atten- 

 tion of producers is directed is the desir- 

 ability of removing or sterilising the fer- 

 mentable albuminous substances present in 

 tlie latex. They give rise to evil odours and 

 become a nuisance, even if they do not in- 

 juriously affect the quality of the rubber 

 itself — a point which is perhaps debatable. 

 As regards plantation rubber, an estimate 

 of the area under cultivation about two years 

 ago gave a total of some 150,000 acres, and 

 this, no doubt, has now considerably in- 

 creased. The chief regions concerned are 

 Ceylon (40,000 acres), the Malay Peninsula 

 (38,000), Africa (33,000), Me.xico (10,000), 

 and India (8000). Young plantations in a 

 more or less experimental stage, covering in 

 the aggregate some 20,000 acres, are also 

 found in Borneo, Java, Brazil, Venezuela, 

 Ecuador, Central .America, and the West 

 Indies. .As to the quality of the plantation 

 rubber, recent experiments seem to indicate 

 that, judged by vulcanisation tests on a 

 small scale, some plantation rubber at least is not 

 inferior to the best " hard cure " Para. The author, 

 however, remarks that up to the present there 

 is a unanimous opinion amongst experts that plan- 

 tation rubber is deficient in " strength " compared 

 with the Brazilian forest product. Nevertheless, it 

 commands a higher price, owing to its greater free- 

 dom from waste. 



"Never before," say some recent writers, " have 

 brokers or manufacturers had presented to them 

 a raw rubber of the purity of the best plantation 

 rubbers." ' 



For this very reason, • they urge, it may well be 

 that the present rough practical tests applied to the 

 raw rubber are insufficient for proper valuation. At 

 present the question of the relative merits is an 

 open one ; we shall probably know much more about 

 it during the next year or two, when larger quantities 

 of the plantation product are expected to come into 

 the market. 



C. .SlMMONDS. 



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