Dec. 1906. J 



461 



Sdps and Exudations. 



The results obtained and published in Ceylon should be compared carefully with those 

 obtained elsewhere, and if other countries will only respond as freely as Ceylon, the 

 Malay Peninsula and India, in giving records of work done, knowledge of the highest 

 importance to the rubber industry will soon be in our possession. The results 

 tabulated for your information to-day are of interest since they show what has been 

 obtained by experiments on every section of tiie tree, from the base to a height of 

 nearly fifty feet. They are at the best only fragmentary and must not be accepted 

 as the standard by means of which probable future yields can be calculated and 

 cheeked. People are only too apt to regard a siugle year's results as something which 

 will serve as a guide for, and stand the test of, the future ; but I am sure that if 

 the friends who visit these places were only in charge of scientific experiments for a 

 few years, they would realise that the main point of interest in all such work is the 

 variability of the results obtained. In all such experiments it is first necessary to 

 determine the range of variability, and from that to calculate the error to be 

 allowed in all experiments, 



HIGH TAPPING RESULTS. 



It will not surprise many of you to learn that the highest yield of rubber has 

 been obtained from trees tapped from the base to fifty feet ; these high tapping 

 experiments were modified and worked on such a plan that the yield has now totalled 

 to about 15 lb. of dry rubber per tree in eleven months ; there can be but little doubt 

 that if necessary, at the sacrifice of the tree, three times that amount could be 

 obtained within one year. The cortical stripping necessary to give such a high yield 

 within one year, would in all probability kill the tree. You will notice that high 

 tapping necessitates two or three coolies per tree per day, a fact which is of some 

 interest to those planters who speculate on their future yields from parts of the 

 stem above 6 or 10 feet. 



LATEX WITHOUT RUBBER, 



There is a very curious phenomenon to be recorded in connection with the 

 tapping of the higher parts of old trees. We all know that when a Para rubber tree 

 stem has a basal circumference of 20 inches or over, it yields normal latex— or at least 

 a milky liquid which can be converted into rubber. The average circumference 

 of the stems at the highest points, tapped at Henaratgoda, is not less than 30 inches, 

 and the stems have usually yielded good latex. But on certain occasions the latex 

 has been of such a nature that it could not be coagulated by any means whatever ; 

 and though this feature has been very erratic, it has been of much more frequent 

 occurrence where high tapping has been carried on. 



The following table shows the results for the last eleven months and the 

 botanical significance of this curious phenomenon will form the subject of future 

 remarks : — 



Number of 



* T ,„ Height of times when Number of t-, f , 



Marks - tapping area. latex not times tapped. Frequency of tapping, 



coagulatable. 



A 5'-6' 91 Twice per week. 



B „ 93 do 



C 1 92 do 



D „ 2 270 Every day. 



E „ 136 Every alternate day. 



P ,, 44 Once per week. 



G ,, 11 Once per month. 



H ,, 1 171 Every day from February 1st. 



I ,, 5 257 Every day from October 1st. 



L 30' 8 931 



M 6'-16' 1 95 | 



N 10'-20' 1 94 I m , + • i • , 



O 20 -30' 2 94 ' Tapped at irregular intervals. 



P 30' 16 7* 



Q 50' 5 84 



J 



