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in working of the two classes of rubber, and in several cases— 

 notably at Silvertown, where accurate tests of all rubbers used are 

 carried out, the recorded figures were submitted to my inspection, 

 and an inferiority of from 8 per cent, to 15 per cent, with different 

 samples was shown. The inferiority of plantation rubber is not 

 only confined to those physical properties which are capable of 

 immediate measurement, but is also shown in the keeping qualities 

 of the rubber. I was shown samples from different estates in 

 Ceylon and the Straits which had been sent home in 1902 and 1903, 

 and which had been preserved in air-tight jars side by side and in 

 the same room with samples of jungle rubbers from South America 

 and Africa. One sample prepared in 1902 was quite perished and 

 rotten, its elasticity was entirely lost, and it was more like a sheet 

 of dough than rubber. Other samples of plantation rubber had all 

 shown marked deterioration in the three years. To compare with 

 these were samples of South American Para of ages up to and over 

 forty years which had preserved perfectly their tough and elastic 

 qualities. This feature of plantation rubber is one which is now- 

 beginning to be realised, and though it probably is due to errors 

 committed in preparation of the samples in question two or three 

 years ago, it confirms practical users of rubber in their opinion that 

 plantation rubber is not reliable, and certainly not the equal of 

 South American Para. 



13. The cause of the inferiority of plantation rubber when com- 

 pared with pure South American Para rubber is not known. Some 

 of the manufacturers believe it to be due to differences in the 

 locality, climate, and conditions under which the trees are grown ; 

 others incline to the belief that the difference in quality is the 

 result of difference in mode of curing and exporting, and again the 

 difference in age of tree from which the rubber is gathered may 

 very probably be the actual reason for the difference in quality of 

 the rubber. There is a further suggestion which has, I believe, 

 never yet been made. The rubber trees of South America which 

 are tapped are selected both by natural and by artificial selection. 

 The condition in South America is, I understand, one of jungle in 

 which the trees affect, and compete with, one another, and this 

 leads to the survival, bv natural selection, of the finest and most 

 sturdy only of the seedlings. The native in tapping selects the 

 best of the trees he conveniently can, and here the influence at 

 work is one leading to the rejection of weak and badly developed 

 trees. On the plantation after the first selection of the stumps 

 and seedlings, no further selective process is actively at work. 1 o 

 determine whether this has any influence on the quality ot the 

 rubber, tapping should be done on specially selected trees, and tne 

 quality of the rubber extracted compared with the average rubber 

 of that plot of trees. All opinions at present must be looked upon 

 as guesses at the solution of this question, the only thing certain is 

 that plantation rubber is inferior, and this certain knowledge is one 

 of the most important results of my visit to England. I propose 

 to endeavour to find out in Singapore and on the Potions 

 themselves, the actual reasons of this inferiority by experimental 



