135 



impossible to handle the rubber, and we found that 3 per cent, 

 was the maximum figure. At about that figure vulcanization 

 became impossible. 



I do not think there is anything more which I can add at the 

 moment to the discussion, except to bring forward these 

 examples of variations which materially affect our working of 

 plantation rubber. 



The PRESIDENT : I think we shall all be agreed that Mr. 

 Williams has given us a very interesting contribution. May 

 I ask whether any other gentleman would wish to speak from 

 the user's or manufacturer's point of view? (There was no 

 response.) Then we will pass to the second division of the 

 subject. 



Mr. SPENCER BRETT (Messrs. Gow, Wilson and Stanton) : 

 Mr. President and Gentlemen This is a subject which has so 

 exercised the minds of scientists that in approaching it I must 

 disclaim all intention of treating it from a strictly scientific 

 standpoint, and in touching upon the various problems involved 

 I wish it to be clearly understood that I hope to offer sugges- 

 tions only, and that I do not presume to be able greatly to 

 enlighten either the chemist or the planter. 



At the outset the very statement that plantation rubber shows 

 excessive variation seems open to argument. It must be 

 admitted that Eastern cultivated 1 rubber has, especially in its 

 earlier years, had to withstand an exceptionally severe ordeal. 

 When the produce of a few isolated trees first reached the 

 market it was examined side by side with a commodity which 

 had been an established commercial proposition for very many 

 years. 



Generally speaking, by the time wild rubber reaches the 

 consumers' works it has gone through a variety of bulking, 

 sorting and grading processes, both natural and artificial, 

 and it is evident that in the early plantation days the conditions 

 were most unequal for comparison. 



Dealing with the present, we are faced with the fact that 

 the quality of plantation rubber does show variation, and in 

 the interests of the industry every step must be taken to 

 standardize the quality to the utmost extent. 



It is now generally known that much of the variation is 

 attributable to differences in any or all of the many details 

 of preparation. It is necessary, however, to go further back 

 than this. A natural variation must exist in the richness and 

 character of the latex as collected from the trees; this again 

 is not only dependent on climatic conditions, but may be 

 directly influenced by the frequency of tapping, elevation or 

 character of lands, length of time during which trees are 

 rested, age of trees, distance of planting and many other 

 considerations. 



