J40 



These experiments favour morning over evening tappings, al- 

 though our evening work commeno <\ as late in the day as possible, 

 starting about 5 o'clock, and for this discrepancy, or rather the 

 effect produced on the flow of late <, there is a very good reason 

 which I fancy, has been overlooke I. From a series of tests and 

 measurements I conclude there can be no doubt that the flow of 

 latex depends entirely on the pressure of water, and the contraction 

 and expansion of a tree during the course of the day is considerable. 

 A tree of 3 feet girth at 3 feet from the ground, measuring exactly 

 3 feet at 6 A.M. would by afternoon, according to the brightness of 

 the day, contract to a maximum of \ inch, and by 6 P.M. or soon 

 afterwards expand to early morning measurement. Or, if a ligature 

 be fixed tightly on a tree it can be observed that in the early morn- 

 ing the ligature is fully stretched, and bv afternoon, if a bright 

 warm day, is quite slack, or partly so, according to the day, and as 

 the evening advances gradually braces up. On wet days the liga- 

 ture is expanded, to tension point and the flow of latex is consider- 

 ably increased, but contains a high percentage of water as is seen by 

 the excessive residuum when the latex has coagulated. In wet 

 weather it seems best to tap some hours after a storm, and to get 

 the best result from evening tappings the work should be deferred 

 as late in the day as possible. 



Doubtless there is one method of tapping Para trees better than 

 others, and the work that is being carried on in so many parts of 

 the world should soon decide which is the one best suited for 

 extracting the maximum yield of latex at the minimum risk of 

 injury to the tree, but for a substantial increase in the yield of 

 latex, I infer that improvement lies in the direction of a thorough 

 knowledge of the requirements of the tree, and it may be necessary 

 for planters to expand their ideas in respect of the distance apart 

 trees should permanently stand, and to obtain a well developed 

 tree which shows a satisfactory annual increment of growth, 30 

 feet apart is but a moderate and rational distance. 



Jt will be seen that in a few instances, tappings have been con- 

 tinued for 18 times, and it will be noted that in nearly every instance 

 the decrease below maximum yield amounted to very little. It ap- 

 pears that on big trees the sear does not increase at the same ratio as 

 on small ones, and had a gross yield been attempted, several more 

 tappings would have been obtained, and as might be expected the 

 2nd, 3rd and perhaps 4th tappings omitted, so that the [ 8th tapping 

 would then have stood as the 15th. Of course there is a limit as to 

 how wide a scar should be, but I have never seen a tree injured by 

 removing an extravagant amount of bark, it is in the depth of the 

 incision that risk of injury lies. 



As to implements for tapping, we have used an ordinary pruning 

 eife and a small 4 inch carpenter s chisel, which have answered 

 the purpose very well. At the present time there are many imple- 

 ments for tapping and so long as it gives a clean cut the one that 

 expedites the operation of tapping most should be the best. The 

 I h inch earpenter's chisel for single incisions is not an implement 



