38 1 



form may be pointed out; if what I said re the formation of latex 

 with regard to the transpiration of trees be correct, it would be 

 interesting to see whether the judicious cropping off of some of the 

 leaves will have any effect on the amount of latex. — I am, etc. 



ISOPRENE, 



(In Times of Ceylon.) 



Colombo, August ^\st. 



PS. — Just as I think of posting this letter, I see a para, in your 

 paper re the formation of rubber by polymerisation from a precursor. 

 The comparison of what I suggest and what Professor DUNSTAN 

 says is at least interesting. 



TAPPING OP PARA RUBBER TREES ON 

 PENANG HILL. 



The following results of certain tappings of Para-rubber trees in 

 the old Experimental Garden on Penang Hill at an elevation of 

 2,000 feet may be of interest, as no trees at this altitude appear to 

 exist elsewhere in the Colony. 



The Garden has been abandoned but on my learning of the exis- 

 tence of the trees, I gave instructions that some should be tapped. 

 The experiments were entirely carried out by MoHD. Hanif, the 

 Overseer of the Botanic Gardens, who has had some experience of 

 the work. 



Owing to the decision to close the Garden the land has become 

 considerably overgrown with small jungle trees, shrubs and ferns, and 

 the trees have had no special care for some time past. There are 

 about 14 trees on the land planted from 30 to 40 feet apart and 4 

 were selected near the road to Government Hill. Their age is about 

 12 years and they stand on a slope about 50 . 



The Overseer adopted the herring-bone method and made the 

 incisions about 2 feet above the ground. The centre groove was 2 

 feet long and the side grooves, 3 on each side, 6 inches long. 



In the first 3 trees, two sets of incisions were made and in the 

 4th tree 3 sets, carpenter's chisel being used for the purpose. The 

 tappings were made on alternate days, 14 in all, between July I ith 

 and August 6th, about 8 or 9 a. m. 



The rubber obtained was thoroughly dried and weighed on the 

 15th September, the results being shown in Table A. 



The girth of the trees is shown in Table B. The average Minimum 

 temperature in the shade during the period of the experiments was 

 65-9° and the average Maximum 78 while the average Maximum 

 in the sun was 124 . 



