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The first tappings were made as follows :— 



In the stems of the trees, as high up as possible, with the aid of an 

 ordinary carpenter's chisel, incisions about 7 c. m. long were made 

 under each other at distances of 25 c. m., at angles of about 30 . 



The distance of the incisions measured along the circumference 

 of the stem was so chosen that the free spaces were about two- 

 thirds of the total circumference in order not to impede the circula- 

 tion of the sap. 



A thin slice was cut away from the lower edge of the incisions 

 with the chisel the next day. This was repeated nine times. 



To catch the latex, a small cup, +8 c. m. wide and + 8 c. m. deep, 

 made of thin t ; n sheeting, was placed under each row of incisions. 



A pin was soldered on to the edge of the cup with which it could 

 be fastened on to the stem". The space between the stem and the 

 edge of the cup was plastered with clay in order to prevent loss of 

 latex. 



From the latex collected in the cups the rubber was obtained by 

 coagulating with alcohol, and afterwards drying in shade and wind. 

 The results of the first tapped tree prove : — ■ 



1. The observations of PARKINS hold true also with Hevea 

 Brasiliensis. 



2. That the quantity of rubber first increases and then declines. 



In order to be able to draw fair comparisons, we must choose other 

 measures than those used so far, where only the yield of the latex 

 of a tree is considered. 



It is clear that the quantity of latex obtainable depends upon the 

 area of bark* which can be tapped. 



The larger the area of the tree the more rubber may one expect to 

 obtain. 



If equal areas of bark yield unequal amounts of rubber on tapping, 

 then the difference is due to the trees themselves or the cause lies 

 outside. In the former instance, we must only choose seeds of good 

 latex-producing varieties, in the latter case we must strive to obtain 

 better methods of cultivation. 



The following two cases may serve to shew this : — 

 Of two trees tapped under similar conditions and methods, one 

 (No. 14) yielded 1214 grammes and the other (No. 9) 1700 

 grammes of rubber. One would now say that tree No. 9 is richer in 

 rubber than tree No. 14. This, however, is not the case as the yield 

 depends upon the surface that is tapped. The tapped surface of tree 

 No. 9 was 2 square metres and that of tree No. 14 was 0*91 M2. f 



* In the calculation of bark surface, the part of the tree to be tapped is looked at 

 as if it were a cut cone, not strictly true, the error is of little consequence, however, 

 to our aim The surface of the sides of this cone is equal to that of a parallelogram 

 of which the equal sides are equal to the circumference of respectively the top and 

 bottom place of the cone and the circumference of the tree is measured at the base 

 and the top to where it is tapped and the distance from the top to the bottom 

 incision. 



t Thia difference is due to the variation? of the thickness of the trunk, 



