TAPPING 



165 



" From the above table the remarkable fact appears that, 

 after three and a half years' steady tapping (making full allow- 

 ance for the fact that Row III. contains only nine trees), Rows 

 IV., V. and VII. each yielded a larger amount of actual rubber, 

 from twelve, ten and eight tappings respectively, than Rows 

 II. and III. from twenty-four and seventeen tappings re- 

 spectively. 



FIG. 44. Single Half-spiral System of Tapping. 



" Turning to the figures for IQOQ-II, it is of interest to record 

 approximately the crop per acre which the yields recorded 

 would produce. The result expressed in pounds is as follows : 



AVERAGE ANNUAL CROP PER ACRE. 



1909-10 

 1911 



II. 



566 

 653 



ill. 



480 

 620 



IV. 



381 

 605 



V. 



364 



565 



VI. 



315 

 490 



VII. 



257 

 360 



" Now the yield for 1911 has increased over the average 

 yield for 1909-10 in every case, but the increase is decidedly 

 greater in the case of the rows tapped at longer intervals. 



