. Agricultural news. Agriculture -- West Indies; Plant diseases -- West Indies. In connexion with Fig. 29, A is equal in length to BC; if the yield for A is taken as 100, two series of experiments gave 1197 and 1239 for B + C. In other words, the double incision gave about 20 per cent, more latex than the single incision. Referring to Fig. 30, it was found that the left-hand tapping C, gave latex equal to 100 when the right-hand tapping D gave 85-7, or approximately 14 per cent. less. In interpreting the results, reference is made to Fetch's discovery in Ceylon that left-hand tapping usually y
. Agricultural news. Agriculture -- West Indies; Plant diseases -- West Indies. In connexion with Fig. 29, A is equal in length to BC; if the yield for A is taken as 100, two series of experiments gave 1197 and 1239 for B + C. In other words, the double incision gave about 20 per cent, more latex than the single incision. Referring to Fig. 30, it was found that the left-hand tapping C, gave latex equal to 100 when the right-hand tapping D gave 85-7, or approximately 14 per cent. less. In interpreting the results, reference is made to Fetch's discovery in Ceylon that left-hand tapping usually yields more latex than right-hand tapping. This was explained on the ground that the fibres of Hevea are not absolutely vertical. In the experiments under consideration the investi- gator attempted to confirm Fetch's hypothesis, which was based on observations obtained with only a small number of \. ^ SO. individuals. This was accomplished by successfully establish- ing experimentally the truth of the following equation :— Yield of AB ^ Yield of EC Sin(a + b) Sin (b-a) AB represents the length of the left-hand cut and BG that of the right-hand cut; a-f b (corresponding angle to b-a) represents the angle formed on the bark by BA and KA, KA being the line [larailel to the latex tubes and runn- ing through the top end of the cut. Similarly b - a is tha angle formed by BC the right-hand cut and the line pass- ing through the upper end parallel to the latex vessels. (See Fig. 31.) The following conclusions are drawn : (1) Fetch's hypothesis is a rational one ; (2) as a method of tapping the half herring bone to the left is preferred to the herring bone or half herring bone to the right ; (3) the ideal angle, would be at right angles to the latex tubes, but as the incision would then be almost horizontal, some arrangement like a gutter, would be necessary to guide the Please note that these images are extracted from scanned page images that may have been digitally enhanced fo
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