RUBBER AND RUBBER PLANTING 57 



reasonable basis for comparison between different ex- 

 periments. For ordinary use on estates a somewhat 

 different system is to be recommended. Such a system 

 will be described in a later chapter. 



The system employed in the experiments was as 

 follows. The tree was first marked with three vertical 

 / lines. Two of these lines were placed exactly on oppo- 

 site sides of the tree, and the third divided the bark on 

 one side between the two first lines into equal areas. 

 From a point on the middle line rather more than a 

 foot above the level of the ground, two lines were ruled 

 slanting upwards at an angle of 45 to meet the lateral 

 lines, thus marking out a large V on the surface of the 

 tree. Above the first V other V's were traced at inter- 

 vals of a foot. The number of V's tapped simultaneously 

 was three in the majority of the experiments. In other 

 experiments, designed for the study of special points, 

 six V's were tapped at once on the same side of the 

 tree; but where no statement is made to the contrary, 

 it is to be understood that the number of V's under 

 operation at any one time was confined to three. 



In the positions indicated by the V's thus traced, 

 grooves were cut in the bark to a suitable depth for 

 tapping the laticiferous tissue without damage to the 

 cambium. The points of the V's were joined by a 

 shallower vertical groove serving to conduct the latex 

 to a cup placed at the foot of the tree to receive it. 

 The above processes constitute the first day's tapping. 

 Subsequent tappings consist in removing a thin shaving 



