206 TROPICAL AGRICULTURE 



BALATA 



Balata is another product resembling rubber but differing 

 in its physical properties from both rubber and gutta-percha. 

 It is the product of Minusops balata and certain other species 

 of trees which occur mostly in Dutch Guiana, Venezuela, and 

 Brazil. M. balata is a large tree, sometimes with a diameter 

 of 6 feet. In Venezuela the trees were cut down and the latex 

 was removed by applying presses to the bark. In this way as 

 much as loo pounds of balata can be obtained from a single 

 tree. In Surinam the trees are tapped by vertical series of 

 jabs which are made in the tree to a height of 20 feet or more. 

 By this method one laborer can collect 4 to 10 gallons of latex 

 per day. From one gallon of latex about 4 pounds of balata 

 are obtained. Balata does not readily oxidize when exposed 

 to the air, contrasting sharply in this respect with gutta-percha 

 and also to a less extent with rubber. It is not ductile and 

 has, therefore, been largely used in the manufacture of 

 machine beltings. 



JELUTONG 



Jelutong is a rubber-like product obtained from the latex of 

 a tree known as Dyera costulata, native to Malaya, Sarawak, 

 Borneo, and Sumatra. The tree reaches a huge size, often 

 measuring 4 to 6 feet in diameter. The jelutong trees are 

 tapped mostly by long V-cuts. It has been found that these 

 trees show the wound response which is also characteristic of 

 Hevea rubber trees. Jelutong trees are tapped about 40 times 

 a year and yield an average of about 60 pounds of jelutong 

 per tree. The latex is coagulated by the natives by various 

 methods, sometimes by stirring with kerosene or powdered 

 gypsum. The latex contains 60 to 70 per cent, of total solids 

 and crude jelutong contains about 10 per cent, of rubber. 

 Jelutong comes on the market in the form of white blocks 

 weighing from 30 to 50 pounds. When tb" ^^^^ nerrentape of 



