CHAPTER XXVI 



SMOKING RUBBER 



IN the Amazon district in Brazil, where the bulk of the 

 world's supplies of " wild " rubber have come from for about 

 eighty years, the method of curing the rubber is simple. The 

 pails of rubber latex are brought in to a hut or roofed shelter 

 for smoking. A fire is made up with bark, nuts and wood, so 

 as to give off a dense and astringent smoke. When this is 

 ready the natives dip a paddle or pole with a flat blade at the 

 end into the pail with the latex and pass it over the smoky 

 fire. In a few seconds a dried film of rubber is formed on the 

 paddle. This operation of dipping and smoking is repeated till 

 quite a huge ball of rubber, composed of countless layers of 

 rubber films, is formed on the paddle. When the ball is too 

 large for convenient handling the paddle is suspended over 

 crossed sticks to relieve the workers of the weight of the heavy 

 ball, and the latex is then slowly poured on in a thin stream 

 on the revolving paddle till no more latex is available or the 

 ball is too large for convenient handling. 



The object of this smoking is to thoroughly cure the rubber, 

 as the latex contains many proteins which would otherwise set 

 up an active fermentation and become putrescent before the 

 rubber reached the warehouses. In the crepe-rubber manu- 

 factured on plantations nowadays these proteins are, in most 

 cases, well washed out in the washing-mills, and thus smoking 

 is not strictly necessary in the case of crepe-rubber. Of course, 

 a second effect of the smoke is to coagulate the rubber. 



When trees first came into bearing on Eastern plantations 

 the latex was allowed to dry on the trees. The scraps and 

 strips of rubber were then collected, rolled up anyhow in a ball 

 or lump and sent to market. This was found to be clumsy and 

 inconvenient, as the rubber was full of dirt and particles of 

 bark. 



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