480 



The Supplement to the Tropical Agriculturist 



owing to the proportion lost on washing. After 

 touching on the influence of age on the trees 

 and discussing the question of yield, the lecturer 

 quoted some figures by Mr H K Rutherford for 

 an estate in Maiay, where 100 to 200 lb. of rubber 

 per acre is being produced at a cost of 10'7-ld, 

 to which should be added 3'3d for freight, pack- 

 ages, etc., and an amount varying from Id to -id 

 per lb. for interest on capital. After noting 

 that the method of coagulating the latex is by 

 adding acetic acid, the lecturer enumerated the 

 varieties of ruhber that are made, crepe, and 

 sheet being the chief. The trying is sometimes 

 carried out in a vacuum drier, but the results 

 vary according to the care with which the drier 

 if? employed. The discovery that an enzymo 

 present in the Hevea latex is destroyed at 183" 

 Fahf. has been utilised to the advantage of 

 the resulting rubber. The lecturer next re- 

 ferred to probable changes in the methods 

 of preparing crude rubber, the improve- 

 ment of the means employed for wild 

 rubber, and the preparation of good robber from 

 low-grade resinous rubber by chemical process. 

 Synthetic rubber then claimed attention, the 

 subject being reviewed from Tilden's isoprene 

 method to Harries's recently published work. 

 The matter resolves itself into a competition be- 

 tween chemists arid Nature, the latter producing 

 rubber which can be put on the market at Is a lb. 

 This is a very large proposition, considering the 

 cost of the materials from which the chemist 

 starts- The analogy of indigo is a misleading 

 one, as indigo only exists in a dilute form in the 

 plant and costs about 3s 6d per lb. The manu- 

 facture of rubber goods was next described, and 

 the methods of vulcanising with sulphur and 

 sulphur chloride were dealt with in detail. The 

 recovery of waste rubber by various processes 

 was considered and the new ' reforming ' process 

 described. The last-named consists in grinding 

 the waste rubber to powder, heating and causing 

 the rubber to cohere by great pressure. 



Discussion. 



The Chairman — opened the discussion. He 

 said the problem of preparing synthetic rubber 

 is similar to that of making artificial camphor, 

 and referred to Harries and Bayer processes re- 

 cently patented for synthetic rubber. An elect- 

 rolytic, method of coagulating rubber has been 

 recently introduced. Sir George Watt referred 

 to his official duties as botanical expert to the 

 Indian Government. Mr. H. K. Rutherford 

 created some amusement by his candid warning 

 about taking the advice of experts, giving several 

 instances where the experts have been wrong. 

 Mr. H. Wright pointedly asked whether Har- 

 ries's work marked any advance of commercial 

 importance. He placed the yield per acre at 300 

 lb., this estimate being based on recent experi- 

 ence. There are today 720,000 acres of rubber 

 plantations in the East, and the British lead the 

 way in the industry. Mr Hammond Smith spoke 

 of the need for quick drying in the wet climates 

 where rubber flourishes. He looked to the School 

 of Tropical Medicine for help in enabling white 

 men to live healthily in West Africa and so be 

 able to supervise the rubber industry in that 

 country. Colonel Burley, as an expert on reco- 

 vering rubber, said he wanted rubber with the 



minimum of resin. Mr FL Ross, engineer to 

 the Re-formed Rubbor Co., described the pro- 

 cess used by his company. He hoped to be able 

 to supply rubber tiles at 11 per square yard ; this 

 would be an ideal floor covering of practically 

 everlasting wear. Mr W F Reid dealt with the 

 question of recovering rubber and of devulcani, 

 sation by means of inert selective , solvents 

 Rubber need not be used for waterproofing pur- 

 poses, a substitute should be found, as the 

 rubber is, he considered, unsatisfactory from the 

 wearer's point of view. Other speakers were Mr 

 Bevan, Dr. Stephens, Dr. Phillips, Mr H C T 

 Gardner and Mr A C Chapman, after which Dr. 

 Schidrowitz replied. Harries's work was not, 

 in his opinion, of commercial importance, and 

 he considered that chemist most unfair in hia 

 trertment of Dr Tilden's paevious work. — Chemist 

 and Druggist, April 9. 



THE RUBBER INDUSTRY OF JAPAN. 



H. M. Commercial Attache at Yokohama (Mr. 

 E F Crowe) has forwarded the following parti- 

 culars relative to the use of various products of 

 rubber in Japan : — 



The subjoined statement of the imports of 

 crude rubbor during the past four years shows 

 how rapid has been the development in the 

 rubber trade : — 



Quantitv, Value, 

 lb. " £ 



190R .... fi06,72 1 < fiSVOO 



1907 .. 693,126 7-, «0U 



19(18 ... 1,039,430 On.FOO 



1P09 .. 1,331,828 150,010 



In the closing months of 1909 there waB a 

 sudden development in Tokio and Yokohama of 

 the use of solid rubber tyres for jinrikishas, and 

 there is little doubt but that the fashion will 

 spread to nearly all the large towns in the pro- 

 vinces, The price naturally varies considerably 

 according to the quality, but it appears that a 

 pair of wheels with tyres costs from 26 yen to 34 

 yen (yen = 2s. O^d.), and the tyres alone from 14'5 

 yen to 18 yen a pair (the diameter of the wheel 

 is 42 inches). It is estimated that these tyres 

 will last two years, but as they have only been in 

 use a short time it is impossible to judge. On the 

 other hand British imported tyres used by the 

 brokers have lasted for over ten years ; similar 

 tyres now cost 30 yen. Most of the tyres now 

 coming into use are manufactured locally, 

 though some few are imported. All the Japanese 

 firms making tyres also manufacture rubber 

 soles for the "tabi" or blue socks which the 

 rikisha men wear ; they also make rubber balls 

 and various other rubber goods. There are many 

 small factories with from 10 to 15 hands, especially 

 in Osaka. The principal consumers of rubber are 

 the electric wire works, which manufacture 

 articles for the use of the army and navy. Two 

 companies are installing plants for making 

 waterproofs for the navy. Japan import sup- 

 plies of crude rubber from the Straits Settle- 

 ments, the Dutch East Indies, the United King- 

 dom and America. Plantations have been made 

 in Formosa, and wild rubber is also found there. 

 —Board of Trade Journal, March 31. 



