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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 oqual 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. 
f This difference is due to the variations of the thickness of the trunk; 
