433 



oblique incisions were opened at about an angle of 45 and re 

 versed oblique incisions at an angle of 135°, much resembling an 

 inverted V, this latter trial came out poorly and was not conti- 

 nued in Experiment // or Experiment 



In these the single, long oblique, and herring-bone methods 

 were tried, daily and alternate days. The best result obtained 

 with the long oblique being under half an ounce of dry rubber to 

 the inch of girth, and as there is the additional work of using 10 

 cups to each tree, while one suffices in the herring-bone method, 

 an extended trial of the herring-bone was made in Experiment / V. 



In this trial one group exceeded half an ounce of dry rubber 

 to the inch and favoured tapping on alternate days which was 

 more fully tested in Experiment V when 7 groups exceeded half 

 an ounce of rubber to the inch, and excepting 4 groups of small, 

 stationary, inside trees, the general result was good. 



Experiment VI was a continuation of the previous trial but on 

 big trees and shows that when we are working on a more deve- 

 loped system of periodical tappings some big averages will be 

 obtained. The yield of group 5 morning, Experiment 6, is parti- 

 cularly interesting, see Appendix D, page 148, this group averaged 

 2 lbs. 10 ozs. per tree and was continued for 28 tappings, the 

 13th tapping giving 30 ozs. of dry rubber, and the 28th tapping, 

 24J ozs. 



COAGULATION OF THE LATEX. 



By the use of a weak solution of formalin we were not much 

 troubled with " Scrap " or rubber which had coagulated within 

 the collecting cups, (although the same remark, under the 

 same conditions, does not apply for the current year.) A 

 practically air-tight chamber capable of drying 300 lbs. of rubber 

 with the aid of Calcium chloride was built during the year but the 

 materials, bricks, cement, etc., were not sufficiently dry for use in 

 the year under review (but it is at the time of writing working suc- 

 cessfully) and all the rubber in the from of "biscuit " was prepared 

 in almeirahs and cabinets, the drying being assisted by Calcium 

 Chloride. 



THE EXPERIMENTS REVIEWED. 



Undoubtedly striking is the difference in favour of morning 

 over evening tappings as already noticed in the appendices, and is 

 due to the pressure of moisture in the mornings by absorption 

 during the night, and the difference on evenings to the excessive 

 evaporation during the day ; in fact, with a tree of 3 feet girth at 

 6 a.m. we have found a contraction on a bright sunny day ex- 

 ceeding a quarter of an inch by mid-day, and at 5 p.m. the same 

 tree had not reached early morning measurement. Evening tap- 

 pings to be successful should be deferred as late in the day as 

 possible and on well laid out estates might be managed with 

 artificial light. On rainy cloudy days the trees are swollen to ten- 

 sion point and the flow of latex excessive but the increase of water 

 is too evident. 



