RUBBER 



367 



The treatment of wild rubber on the Amazon is somewhat 

 different. V-shaped incisions are made in the bark, and at the 

 bottom, of each cut a small collecting cup is placed. The latex, 

 which contains about one-third of its weight of rubber, is then 

 coagulated by exposing it to wood smoke which, of course, is 

 accompanied by small quantities of acetic acid and vapour of 

 creasote. In order to accomplish this the collector uses an 

 earthen bottomless pot in which a smoky fire is made by igniting 

 a pile of dry twigs, to which is added from time to time the nuts 

 of a kind of palm abundant in the district. A long wooden paddle, 



Herring bone. Half herring Basal V Spiral. 



bone. system. 



FIG. 130. VARIOUS SYSTEMS OF TAPPING. 



of which the blade is first smeared with wet clay to prevent the 

 rubber from sticking, is then dipped in the latex and held in the 

 smoke. A thin sheet of coagulated rubber is then almost 

 immediately produced, and by alternately dipping in the milk 

 and rotating the paddle over the fire, successive layers of rubber 

 are deposited until a ball is produced of the required size, which 

 in as much as a man can conveniently lift. The ball is then split 

 by means of a moistened knife, and the rubber detached from 

 the paddle. As the latex contains, beside rubber, a considerable 

 quantity of albuminous matter, of which a portion is retained by 

 the rubber, it is necessary to sterilise it, otherwise the impurity 



