June, 1909.] 



India, the Federated Malay States and 

 elsewhere. These are being cultivated 

 upon the Peradeniya Experiment Station 

 with the object of obtaining seed for 

 distribution and trial at different eleva- 

 tions and on different soils. Specimens 

 of the roots and nodules of each pro- 

 mising variety are to be sent to the 

 Nitrobacterine Co. for the preparation 

 of a special culture for each. 



The habits of the various leguminous 

 plants which may be expected to prove 

 useful in this way differ considerably. 

 They vary from the upright bushy 

 forms with more or less woody creeping 



stems to the low creeping species which 

 entirely cover the soil and only attain 

 a height of a few inches. Some again 

 are of no value as food for cattle, whilst 

 others are grazed upon with relish. It 

 is possible that within a few years the 

 grazing of cattle upon rubber estates 

 may prove the best means of keeping 

 this crop in a vigorous and healthy 

 condition. Nitrobacterine may prove 

 careful in establishing such leguminous 

 herbage, and it is hoped that experi- 

 ments in this direction may be under- 

 taken. 



R, H. L. 



GUMS, RESINS, SAPS AND EXUDATIONS. 



THE YIELD OF WILD AND 

 PLANTED "PARA" RUBBER. 



(From the India Rubber World, Vol. 39, 

 No, 4, January, 1909.) 

 What is the yield of a rubber tree ? 

 Simple as the question may appear — 

 and it is asked incessantly— giving an 

 intelligent answer to it is by no means 

 simple. One must consider what 

 varieties of rubber are involved, where 

 the tree grows, whether "wild" or 

 " cultivated," and, if the latter, the con- 

 ditions under which planted- A remark 

 may be recalled here from a report by a 

 former British Consul at Para writing of 

 native Heveas in the Amazon region : 

 "two trees growing close together and 

 under apparently precisely similar con- 

 ditions will often vary very much as 

 regards their yield." 



There is no question that rubber trees 

 do yield, else what would become of the 

 rubber market? On one day during the 

 past month the Customs authorities at 

 New York reported the arrival of rubber 

 of an invoice value exceeding $2,000,000. 

 The Custom House at Para dealt last 

 year with 80,638,800 pounds, and some 

 years the figures have been larger. 

 Besides, the Amazon region doesn't sup- 

 ply all the rubber used. We hear over 

 and over again that the Brazilian rubber 

 is derived from trees scattered in dense 

 forests, and that the native tappers gain 

 a very small amount of latex from each 

 day's tapping. But the Para shipments 

 argue either a tremendous number of 

 wild rubber trees or a very considerable 

 average annual yield per tree, 



Since it must be admitted that trees 

 do yield rubber, the question remains, 

 how much ? This subject, as relating to 

 forest rubber, has been treated at some 



length in former numbers of The India 

 Rubber World, including quotations 

 from Mr. Vice-Consul Temple, who once 

 reported having had access to the books 

 of some operators in the Brazilian field, 

 indicating an average yield of 2*2 to 3*3 

 pounds yearly per tree. He was of the 

 opinion, however, that very many trees 

 were being worked with no larger aver- 

 age yield than l'l pounds. His report, 

 however, had to do only with the state 

 of Para, where the rubber fields have 

 been worked longer and more.thoroughly 

 than in the river regions. It does not 

 seem to have occurred to the Amazon 

 rubber trade to consider the yield of 

 individual rubber trees so long as total 

 results are satisfactory. But chance 

 details which have come to hand from 

 time to time point to the probability of 

 a yield of i to 10 pounds yearly per tree, 

 varying with the degree to which 

 estradas have been " worked out." 



With the coming of cultivated rubber 

 on plantations owned by capitalists and 

 with shares listed on stock exchanges, 

 the question of yields becomes of parti- 

 cular interest in connection with the 

 analysis of company reports. If one 

 tree will afford a given quantity of 

 rubber, will 1,000 give a thousandfold? 

 In considering any of the figures which 

 follow— all relating to the yield of plant- 

 ation Para (Hevea) in the Far East — it 

 must be remembered that such yields 

 may be influenced — 



By the character of the soil, altitude, 

 or climatic conditions, 



By the coarseness or width of the 

 planting, 



By the frequency of tapping, 



By the method of tapping, 



By the care with which the latex is 

 handled, 



