Gums, Resins. 



134 



though well cleaned and washed on the estate, would for fine work have required 

 re-washing. The separate sheets of ci^epe had adhered firmly into one solid mass which 

 required a crowbar to separate into the original layers, and the whole had shrunk 

 leaving a space of about an inch between the rubber and the sides of the case. If any 

 wrapping to prevent the intrusion of dust and grit be used, it should be either smooth 

 and strong such as sheet zinc lining or else made adherent to the sides of the cases — 

 as, for instance, strips of smooth paper pasted over the joints in the wood inside the 

 cases. With less perfectly prepared rubber in biscuit, or worm form, which will re- 

 quire washing before use, a less careful form of packing might be adopted. It must be, 

 of course, always remembered that the rubber is valued by its appearance very largely, 

 and uniformity in size and colour of the sheets will have some influence in determining 

 the price, though really being no guide to the actual quality of the rubber. 



QUALITY OP PLANTATION RUBBER. 



11. On this subject I met with a perfect uniformity of opinion among those 

 who had practically made trial of Straits aud Ceylon rubbers. All were agreed that 

 the rubber was good aud very serviceable, but that it was by no means as good as 

 South American fine Para, either hard or soft cure. The plantation rubber is lacking 

 in nerve, it works soft between the masticating rollers, aud its keeping qualities are 

 inferior to South American Para. After vulcanisation the tensile strength is less and 

 the elastic recovery of shape after deformation by stretching or compression is less 

 perfect than shown by South American Para under precisely similar conditions. 

 This result is disappointing and quite contrary to the report which the late Dr. 

 Weber made on plantation rubber, when he stated that he found the tensile strength 

 to be superior to that of South American hard-cure Para. 



12. That the result of practical experience of the rubber manufacturers 

 must be accepted there can be no question. There was no hestitation on their part 

 in demonstrating to me the difference 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 Avere shown. The inferior- 

 ity 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 juugle rubbers from South America 

 and Africa. One sample prepared in 1902 was quite perished and rotten, its elasti- 

 city 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 planta- 

 tion rubbber is not reliable, and certainly not the equal of South American Para. 



13. The cause of the inferiority of plantation rubber when compared 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 



