46 



of plantation Rambong on the market. An analysis of well 

 prepared Rambong compares favourably with the best 

 Para, there is very little difference in respect of caoutchouc, 

 but the percentage of resin and proteids is slightly higher. 



In Java the Netherlands' government have rubber 

 plantations comprising nearly 15,000 acres of mostly Ram- 

 bong. 



In Africa moderate grade rubber is obtained from 

 Picus Vogelii. 



C a si ill on elastica (Ule, Central American rubber, or 

 caucho-ball) is a native of Central America including 

 Mexico, Guatemala, Nicaragua, Panama, Honduras, parts 

 of Colombia to Peru; and when fully grown is the largest 

 of all rubber trees. Owing to excessive trapping — and 

 very often felling — most of the large indigenous trees are 

 already exterminated, but a considerable area in Mexico 

 — estimated at 100,000 acres — is already under cultivation 

 — a factor which must not be lost sight of in considering the 

 future prospects of the rubber market. In the West In- 

 dies, too, cultivated Castilloa is a rubber which it is ex- 

 pected will be heard of in the future. The yield of rubber 

 from Castilloa is high, being about the same as Para and 

 varies from 2 — 16 lbs. according to the size and age of the 

 tree. The latex has an acid re-action and cannot be cured 

 by smoking. It is coagulated by boiling, or sometimes with 

 the addition of alum or salt, or a decoction made from the 

 stems of the moon-flower. A much improved process for co- 

 agulating the latex by means of separation is now adopted. 

 With the aid of a machine rotating about 6000 times per 

 minute the particles of caoutchouc are separated in a few 

 minutes into a white layer and can then be taken off and 

 dried. It is expected that all the future plantation Cas- 

 tilloa will be prepared by centrifugalising and a better 

 marketable rubber will thus be obtained, as by this method 

 of preparation the high percentage of resin can be dis- 

 posed of. The nerve or tensile strength of Castilloa is not 

 so good as Para, neither has the rubber ever obtained so 

 high a price. At the time of writing caucho ball (dirty 

 scrappy Castilloa) is quoted at 3/10 against 5/H for fine 

 hard Para. 



The attempted cultivation of this species in British 

 Malaya can only be described a failure. 



