PARA-RUBBER CULTIVATION 



599 



attention once more on the Amazon smoking method. Wick- 

 ham J for one strongly advocates this practice, and has invented 

 an apparatus for the purpose. 



Some of the Eastern estates have met the difficulty half 

 way by first preparing the rubber in thin sheets by means of 

 acid coagulation and then submitting these to the action 

 of smoke from burning wood. The rubber is thus surface-cured 

 only. It has just been pointed out that rubber so treated 

 (smoked sheets) fetches at present the top price in the 

 market. Previously pale crepe was most in favour, largely on 

 account of its light colour. A cured rubber, retaining its pale 

 tint, would seem to be the desideratum, and this would be 

 difficult to obtain by any smoking method. Consequently it 

 would seem likely that a wet system both of coagulation and 

 curing will ultimately be adopted in Para-rubber cultivation ; 

 especially as a watery or much diluted latex can more easily 

 be dealt with by wet coagulation than by means of smoke. 



Electrical Method of Separation 



Cockerell, 2 of the Ceylon Technical College, has recently 

 shown that rubber can be separated from Hevea latex electri- 

 cally. The caoutchouc is deposited on the anode. Few details 

 are to hand yet. In any case it is doubtful if such a method 

 would be practicable on estates. Nevertheless it is of con- 

 siderable scientific interest. 



Composition of the Latex and Rubber 



A moderate number of analyses have been made of Hevea 

 latex and rubber ; several are by Mr. Kelway Bamber, chemist 

 to the Ceylon Government. Below are given in round figures 

 the average percentage composition of the latex drawn from 

 the tree-trunk (after wound-response has commenced) and also 

 that of the rubber prepared therefrom. 



Hevea Brasiliensis percentage composition. 



Water 

 Caoutchouc 

 Resin 

 Protein . 

 Ash . 

 Sugar, etc. 



1 Wickham, The Plantation, Cu 



'tivation and Curing of Para India Rubber, p. 29. 



3 Cockerell, India-Rubber Journal, 1909, 37, 331. 



