January i, 1906.] 



THE INDIA RUBBER WORLD 



111 



and quite ready to be tapped again. This has all been proved 

 In practical work on Deviturai estate. 



YIELD Ol' KUnBF.K. 



The yields obtained by this method are surprising, and have 

 totally upset all former calculations. Where formerly one pound 

 of rubber per annum was considered a fair yield, now five 

 pounds can be obtained. In 1903, with the V system of tapping, 

 248 trees gave 240 pounds of rubber. Tapped in 1904, on the 

 spiral system, these 248 trees (rising 1 1 years old) gave 65 pounds 

 the first month, and in 3 months gave 392 pounds rubber ; and 

 in January September, 1905, the same 248 trees gave 1317 

 pounds rubber, by spiral tapping. 



On a visit to the Deviturai estate in October, 1905, the writer 

 was privileged to copy the following extract from the estate re- 

 port for September : 



The year's tapping on the new system closed]with this month, with an 

 average yield of just over 5 pounds per tree. The 8 separate trees 

 tapped 8 months yielded 14 pounds each, and the 40 young trees in 4 

 months tapping gave 132 pounds each. 



The " 40 young trees " mentioned were being tapped for the 

 first time, and they gavetotal yields up to 19 and 21 pounds per 

 month. The "8 separate trees" mentioned had an average 

 girth of 42 inches, and in March, April, and May respectively 

 they gave a yield of 14, 19, and 17 pounds of rubber, and in 

 September (after having been rested during the seed crop) 

 they gave 18 pounds for the month. Rising 12 years old, these 

 trees have given an average of 16 pounds per tree per year. 



The spiral system requires very careful tapping work, and 



'WORM RUBBER." 



[Specimen from Ceylon, obtained in the American market and photographed 

 by Thk India Rubber \\N>Ri.r>.l 



length of long spiral cuts, a little water is poured into the top 

 of the cut by the tapper. 



In reopening the cut a very thin slice of bark is shaved ofl 

 the lower edge of the open wound — for healing of the wound 

 always takes place more rapidly from above downwards. The 

 finer the shaving taken off the better, for all that is required 

 is to open the laticiferous cells and the less bark removed 

 each time the more economical is the tapping. The first knife 

 will not do this. Here comes into use the Bowman-Northway 

 No. 2 knife, or paring knife. This knife has a fine steel spring 

 which presses against the open wound of the trunk and pre- 

 vents the Cambium being pierced, while the sharp edge at the 

 side shaves off a very thin layer of latex and reopens the cells 

 containing the milk. 



Alternately with this paring knife is used the " Pricker." 

 This is like arevolving wheel spur on a handle, and is run along 

 the wound close to the lower edge of the cut. It produces a 

 series of pricks right along the cut. The flow of latex pro- 

 duced is no less than that made by the knife ; but the primary 

 object is to bleed the tree without further bark removal. The 

 trees are tapped on alternate days, and also alternately with 

 the knife and the pricker. By this means one inch in width of 

 bark is removed per month ; the trees are tapped one month 

 and then given one month's rest, so that in one year—/, e., six 

 months' actual tapping — 6 inches of bark are cut away, and 

 thus it takes exactly two years to cut down the trunk until the 

 old wound of the parallel spiral below is met. By that time the 

 bark is renewed perfectly smoothly and evenly, is full of latex, 



''LACE" OR ''CHEPE" RUBBER. 

 [Specimen from Ceylon, obtained in the American market and photographed 

 by The India|Rubb«r World.] 



