Oct, 1906.] 



289 



Saps and Exudations. 



treat the latex while in a liquidjcondition with these compounds. Is it possible to 

 carry on such work on an ordinary estate, or must the whole of that latex be sent 

 down to some central factory in Colombo or Kandy, or wherever the most convenient 

 centre may be '? If it is necessary to send down the whole of the latex to a central 

 factory, I am rather afraid there may be some difficulty in fixing its real value. 

 From day to day on different trees, on different estates, and on different days, we 

 know that the composition of latex varies considerably. It is not enough to say here 

 are a few gallons of undiluted latex, because the samples even from different trees 

 on different days may possess anything you like from 40 to 90 per cent, of water ; 

 so it seems rather difficult if you have a central factory to really arrive at a satis- 

 factory arrangement ; but if it could be carried out on the estates then I think 

 the idea would be more congenial. 



Mr. Bambbr, replying to Mr. Wright, said it was quite possible to add solid 

 sulphur compounds to the freshly coagulated rubber and mix it in the ordinary 

 machines, but he did not think himself there would be any difficulty in ascertaining 

 the correct amount of rubber in the latex. If the rubber was sent down in casks 

 to a central factory, it would be well mixed before it reached the factory, and 

 it would be easy to accurately ascertain the amount of actual rubber in it 

 from a proportionate part. They could take out a sample, cure it in a few minutes 

 compress it between drying sheets, and then weigh the rubber, and they could 

 calculate how much there was in the total bulk of latex of actual rubber. It 

 would be quite simple if they did not wish to wait until the rubber dried to 

 make out a table with the corresponding weights of wet and dried rubber. As 

 regards the specific gravity, the readings were far too uncertain to draw correct 

 deductions from as to the amount of rubber in the latex, because it varied so much 

 with the matter in solution either from the latex itself or sap. 



Mr. Wright: — Then I take it that the planter would not really know the 

 value of the latex he sent until it had been determined at the factory. He could, 

 of course, take counter readings. 



Mr. Bamber :— It would be possible for the planter to do it himself before 

 sending it away. 



Mr. Wright :— In association with that it might be possible to accumulate 

 latex in large quantities and keep it in a liquid condition by the addition of 

 ammonia. We have been making experiments here with the different latices, 

 and our idea has been to find out how long the latex can be kept in a liquid condition 

 by the addition of formalin or ammonia, and I should rather like to ask Mr. Bamber 

 whether, in the event of its being necessary to keep latex in a liquid condition for 

 several weeks, it is likely certain chemical changes might not take place. I have 

 samples of rubber prepared from latex kept for six weeks, and I am sorry to say 

 they are inferior ; while one might have expected them to be perfect. I am speak- 

 ing with reference to Para rubber, and Mr. Bamber will perhaps tell us whether 

 any chemical change does take place. 



Mr. Bamber said that he did not think when formalin is used there was 

 much chemical change, but in the case of ammonia he thought it was quite possible, 

 there would be some change. He had kept latex in his laboratory for two 

 or three weeks without any deterioration whatever. 



Mr. Wright :— Two or three weeks ! 



Mr. Bamber : — I think I could have kept it six or ten weeks. The only thing 

 he saw was that when he worked it into biscuits it coagulated a little more rapidly 

 than when it was fresh. The moment the acetic acid was added, the whole at once 

 set into a solid mass which was in a way rather a nuisance as they did not want 

 it to set too quickly. He did not think there was any fear so long as there was 

 no excess of formalin— more than sufficient to prevent bacteria forming. 



