Gums, Resins, 



388 



November, 1909.] 



of the small portions of the bark which 

 tapping implies being in the case of a 

 tree of 20 " or more in girth so slight an 

 injury as to be negligible. 



The best and simplest criterion for 

 deciding how long to continue tapping 

 is found in keeping a record of the 

 amount of latex from each tree from 

 1,000 trees or from a field. If these 

 figures show no serious and continuous 

 decline there is no reason to stop tapping. 

 On the other hand when, after a series 

 of tappings, say 40 or 50, the amount of 

 latex obtained decreases in a marked 

 manner, and this decrease is constant, 

 the yields being less and less, then it is 

 advisable to stop for a period of a month 

 at least, and not to begin again until by 

 an experimental tapping it is found that 

 the flow is again large. 



On one estate the tapping for a number 

 of cuts was habitually stopped when 

 the yield had attained the maximum, 

 and after some weeks' tapping again 

 produced less yield which increased till 

 the arbitrary time of ceasing. The 

 method, which is adopted to a great 

 extent from fear of using too much bark, 

 is most unprofitable as it leads to 

 stopping before the best yields have 

 been obtained. 



It is naturally wise to so arrange 

 tapping operations that it will not be 

 necessary to retap renewed bark for 

 some considerable period, but we do not 

 yet know by experiment in the Malaya 

 States, what length of time is necessary 

 for a healthy tree, carefully tapped, to 

 produce new bark containing a large 

 number of well-filled latex vessels. The 

 time of four years has been arbitrarily 

 fixed by some planters, and their tapping 

 schemes are arranged in relation to that 

 period. That four years, thiee years, 

 or two years are necessary for the 

 formation of bark suitable for tapping 

 cannot yet be definitely stated, but it is 

 highly probable from isolated cases 

 where such experiments have been made 

 that four years is unnecessarily long. 



Experimental work and observations 

 on tapping and yield of rubber made in 

 Ceylon are unfortunately of little value 

 for Malaya. The climate of Ceylon 

 rubber districts, with its periods of dry 

 weather, is not comparable with the 

 conditions in Malaya, where rubber trees 

 are in active growth of root, leaf and 

 other tissues practically every day of 

 the year, and where, even when they 

 are leafless, the growth of trees is not 

 entirely stopped. 



On one estate in Perak the yield of 

 dry rubber per acre was 800 lbs., a little 

 less than 4 lbs, per tree, even though the 



trees were crowded together 220 to the 

 acre ; this rubber was sold at an average 

 price of some 4s. per lb., thus realising 

 about £160 gross profit per acre, of which 

 more than 50 per cent, must have been 

 net profit. 



Preparation of Rubber for the 

 Market. 



There is still no agreement as to the 

 best form in which to prepare rubber 

 for the home market; block, crepe, 

 sheet and biscuit are made by different 

 planters for different reasons. 



One reason which makes it difficult tor 

 the producer to make up his mind as to 

 the best form in which to make his 

 rubber is that it is not easy to find what 

 the broker and the manufacturer like 

 best. A big price for a break of crepe 

 gives the impression that this form is 

 desired, and will fetch a better price 

 than block or sheet. Shortly after a pur- 

 chase of block rubber at a price higher 

 than the rest on the market seems to 

 imply that this kind of rubber is wished 

 for. 



The leading brokers, buyers, and manu- 

 facturers themselves when asked as to 

 their opinions are found to differ, and so 

 for the present it must remain an open 

 question whether block, crepe, or sheet 

 will get the best reception of the Euro- 

 pean market. 



Light colour and uniformity all 

 through the sample are beginning to be 

 considered as qualities to be aimed at, 

 though the former character is proba- 

 bly only desired by the manufacturer 

 for a class of goods which can never 

 consume a very large quantity of raw 

 rubber, and, therefore, if all prepare to 

 this standard too much may be supplied. 



All who have studied the matter, or 

 who have technical knowledge and ex- 

 perience, are agreed that the most im- 

 portant quality to be arrived at in plant- 

 ation rubber is "nerve," "fibre," " pull," 

 "strength," or whatever other terms may 

 be used for the possessions of elasticity 

 and resilience to a high degree. If this 

 character of Malayan plantation rubber 

 is continued and improved, there is no 

 reason to doubt that the manufacturer 

 will in a short time begin to set a value 

 on it equal to, and perhaps better than, 

 that given to the Para of Brazil. 



The exclusion of all latex which may 

 contain too much viscine, resin, etc., 

 since it is obtained from young trees, 

 " bulking " latex is strongly to be recom- 

 mended ; there is always a market for 

 poorer values of rubber by themselves, 

 and the inclusion of a small quantity 

 of inferior latex may considerably 



