37 1 



important observation that when isoprene prepared from oil of 

 turpentine is kept for sometime, it gradually passes into a substance 

 having all the characteristic properties of Caoutchouc." Professor 

 DUNSTAN then points out thar chemistry holds the key to the future 

 of the rubber industries in all their phases. "The discovery of better 

 methods of coagulation, preparation and purification will be effected 

 through chemical investigation as will also the determination of the 

 manner of utilizings the various other plants which furnish rubber 

 like latices. That the physical properties of raw rubber on which 

 its technical value depends are to be correlated with the chemical 

 composition of the material there can be no doubt. The chemical 

 analysis of raw rubber as at present conducted is however not 

 always to be taken by itself as a trustworthy criterion of quality 

 and more refined processes of analysis are now needed. Although 

 the finest Caoutchouc for technical purposes is only yielded by some 

 half-a-dozen plants under the name of which these varieties of Caout- 

 chouc pass there can scarcely be a doubt that the elastic substance 

 in each case possesses a very similar if not identical chemical 

 structure. Nearly all the latices and similar fluids supplied by 

 plants contain more or less Caoutchouc. Even opium, the dried 

 juice of the capsule of the poppy contains Caoutchouc, whilst the 

 opium yielded by certain Indian species contains a notable pro- 

 portion. Chemistry must determine the means by which Caout- 

 chouc can best be separated from these relatively poor latices. In 

 view of the increasing production of the nearly pure Caoutchouc 

 which is furnished by Hevea, Funtumia, Castilloa and Ficus elastica, 

 and a few other plants which occur or can be cultivated in several of 

 our tropical possessions, the question is not a pressing one at the 

 moment. 



The production of Caoutchouc by chemical means has been vir- 

 tually accomplished in its formation from . isoprene. The exact 

 nature of this change has still to be determined. When this has 

 been done it will only remain to cheapen the cost of production, to 

 make the manufacture of synthetic rubber a purely practical pro- 

 blem. 



It has to be remembered that the actual cost of producing raw 

 rubber which is at present about a shilling a pound will probably be 

 reduced and the market price of rubber may be so considerably 

 lowered that as with quinine the synthetic production could not 

 profitably be carried on. Chemists may, however, confidently predict 

 that before the British Association again meets at York, the synthe- 

 tic production of rubber will be a fully accomplished fact." 



He then refers to the vulcanising of rubber and to the recent 

 experiments of Mr. Bamber in vulcanising fresh latex, and says 

 that if this proves to be practicable it may mean the transference 

 to the tropics of the vulcanizing industry. 



I have quoted at length from this very important and interesting 

 paper, not only because of its intrinsic interest, but because it so 

 frequently happens that persons interested in rubber or other indus- 

 tries frequently see only a garbled account of such investigations 



