238 



per acre. Taking the average of 4 bags, this gives £l6 per acre, 

 so that, deducting the cost of the rubber extraction, the return from 

 the cacao and rubber would be from £4 to £6 more. 



By applying some nitrogenous manure to supply the deficiency 

 in the soil arising from the absence of the Bois Immortel tree, this 

 figure would doubtless be increased. It is also probable that the 

 rubber could be planted closer than 24 feet. 



INFORMATION REQUIRED. 



There are several points on which rubber growers are anxious 

 to obtain information, among these being : — 



1. A method of tapping the tree that would dispense with the 

 claying of the cups, and also any improvement on the method of 

 tapping with the chisel and mallet. 



2. The reason of the difference in yield of latex in trees of the 

 same age and size. 



3. Whether the yield of latex could be increased by the applica- 

 tion of manure, and if so, what particular manure. 



4. The constituents in the soil specially required by Castilloa. 



5. In making oblique cuts in the tree, it is believed that a cut 

 given upwards is preferable to a downward cut. Why is this ? 



6. With Para rubber the yield increases after the first few tap- 

 pings, when carried out on consecutive days, but this does not 

 appear to be the case with Castilloa. It would be interesting to 

 find out the reason of this. 



A cut on the Castilloa, of course, drains a greater extent of the 

 tree at the first tapping, but why does the yield of the Para, which 

 is small comparatively on the first days of tapping, increase ? 



It is hoped that some members attending the Conference may be 

 able to give some information on 'hese points. 



The President : Mr. Hart has closely associated himself with 

 the question of rubber planting in these colonies, and I would ask 

 him to review Captain Short's paper adding any further informa- 

 tion he may have on the subject. 



Mr. J. H. Hart (Trinidad) : Captain Short states that it appears 

 that Castilloa rubber will grow well at 900 feet above sea-level. 

 I think he is quite correct in that statement as I have seen Castilloa 

 growing in its native country, Central America, at that elevation. 

 I cannot, however, follow him in the statement made in one part 

 of his paper, taking it with that made in another part in connexion 

 with shade. He is of opinion that no shade is required for Cas- 

 tilloa in good soil, but that it requires a certain amount of shade 

 for the first two or three years. This would seem to show that 

 Castilloa does require shade in some places. Experiments carried 

 out in Trinidad prove most decidedly that Castilloa does require 

 shade It does not grow with the same vigour when exposed to 

 sun as when partially shaded. I do not mean by shade, such 

 shade as is given to cacao, but a growth of trees of similar size by 

 the side of Castilloa, as it would grow in its natural forest. Dr. 

 Weber, in late writings in the India Rubber Journal, expresses the 

 same opinion and comes to the conclusion that Castilloa requires 



