pi 



At what 

 interval the 

 incisions 

 should be 

 renewed. 



Collection of 

 the latex. 



Coagulation. 



Yield. 



the incisions was not decided, as in some cases the tree continued 

 to exude latex even after having been tapped on thirty consecutive 

 days. In a few cases the maximum yield was attained on the 

 eighth day ; while, in others, there was a gradual increase up till 

 the fourteenth tapping. This difference in the behaviour of trees 

 makes it impossible to lay down any hard and fast rule as to 

 the number of times it is advisable to renew the incision, but in 

 the majority of cases the maximum yield will probably be reached 

 at the tenth or eleventh renewal. 



9. Nor does it appear that there is anything to be gained by 

 allowing the trees to rest a few days before renewing the incision, 

 for the yield of those trees on which the incisions were renewed 

 daily was equal to, and in some cases exceeded, that of trees which 

 were tapped at weekly intervals. The ultimate result, therefore, 

 would seen to be dependent, to some extent, upon the number of 

 times the incisions are renewed, and it is doubtful if a saving of 

 labour can be effected by renewing the incisions at long intervals. 



10. Ordinary cigarette tins were used for the collection of the 

 latex. These were attached to the tree by a small nail driven 

 through a whole in the side of the tin, a little clay being placed 

 between the tin and the tree to prevent any latex trickling down 

 behind. 1 have had some similarly shaped tins made with a "lip " 

 which is filed at the edges. The lip is simply pressed into the 

 bark, no nail being required, while any escap 1 of latex is impossible, 

 A loose lid prevents any dirt or pieces of bark from failing into the 

 latex. The latex exudes very slowly, and it was generally found 

 necessary to leave the tin on the tree for about an hour after mak- 

 ing the incision. 



11. Several methods of preparing commercial " india-rubber " 

 from the latex were tried, and coagulation by the addition of mer- 

 curic chloride, sodium chloride, alum, acetic acid and other reagents 

 was effected, but as these are still under consideration I do not 

 intend to dwell upon them here. I am satisfied, however, that a 

 good marketable rubber can be obtained, at a very small cost to 

 the producer, in three or four days, if he has 

 accommodation at his command. 



1 2. The difference in yield of trees of the same age and growing 

 under similar conditions is very remarkable, making experimental 

 work difficult, especially when the number of trees at our command 

 are limited. The amount of dry rubber obtained from 9-year-old 

 trees varied from 7 to 81 i ozs. The average yield per tree was 

 just under 2 lbs.; but, had all the trees been tapped on the most 

 approved style and the incisions renewed an equal number of 

 times, this amount would doubtless have been exceeded. 



13. The youngest trees tapped were 6 to 7 years old, and gave 

 an average return of 12^ ozs. of dry rubber. This was the result 

 of fourteen days' tapping — i.e., the incisions were renewed on four- 

 teen consec utive days, so that the average yield per day was less 

 than I oz. of dry rubber. As [jointed out at the commencement of 



suitable drying 



