Gums, Resins^ 



132 



[March 1907. 



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 dozsn plauts, under the names of 

 which these varieties of caoutchouc; pass, there can scarcely be a doubt, that the 

 elastic substance in each cas3 possesses a very similar, if not identical, chemical 

 structure. Nearly all the latices and similar fluids furnished by plauts contain 

 more or less caoutchouc. Even opium, which is the dried juice of the capsule of the 

 poppy, contains caoutchouc, whilst the opium yielded by certain Indian species 

 contains a notable proportion. Chemistry must determine the means by which 

 caoutchouc 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 

 brasi'Jeiifii'i, Funtumid eLastica, CastiUoa elastica, Ficus elasticd, 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. 



Moreover, it cannot be doubted that chemical science will sooner or later 

 be able to take a definite step towards the production of rubber by artificial means. 



The production of caoutchouc by chemical means has, indeed, virtually 

 been 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 problem. I should be the last to discourage the great extension 

 of rubber planting which is now taking place. It is warranted by the present 

 demand for the material. It has also to be remembered that the actual cost of 

 producing raw rubber, which is at present about one shilling per pound, will pro- 

 bably be reduced, and the market price of rubber may eventually be so considerably 

 l°wered that as with quinine, the synthetic production could not be profitably 

 carried on. That is a question which involves many factors at present unknown, 

 and only time can decide. Chemists may however, confidently predict that before 

 the British Association again meets at York the synthetic production of rubber will 

 be a fully accomplished fact. 



As I have said, our science is concerned with nearly every problem connected 

 with the great rubber industry, and in concluding these few remarks I may allude to 

 the production of vulcanised rubber depending on the formation of additive com- 

 pounds of the hydrocarbon with sulphur. In this connection I should mention 

 the recent experiment of Mr. Bamber in Ceylon, which appear to show that vulcani- 

 sation may be accomplished by acting on the uncoagulated latex with chloride of 

 sulphur.* If this proves to be a practicable, it may mean the transference to the 

 tropics of the subsidiary industry of vulcauisatiou, which is at present carried on 

 in Europe. 



Owing to the importance and interest which attach to the chemistry of 

 rubber, it is to form an important feature in the work of this Section at the York 

 Meeting, Papers will be contributed by some of the best known workers in this 

 field, by Professor Tilden, and by Professor Harries of Kiel who will give an 

 account of his recent work ; whilst Mr. Pickles, of the Imperial Institute, will 

 present a report summarising the whole of our chemical knowledge of the subject. 



THE RUBBER INDUSTRY IN ECUADOR. 



Consular Report. 

 The tropical forests of the coast provinces of Ecuador are the native habitat 

 of the rubber tree CastiUocl elastica, and the exportation of the rubber derived 

 therefrom has been now goiug on for upwar ds of half a century. For the collection 



[* ^Tlus~is a slip on Professor Dunstan's part. ^Chloride of Sulphur cannot bs used for this 

 purpose, as it decomposes on contact with water f-E£>< T,A>] 



