366 CHEMICAL DISCOVERY AND INVENTION 



RE-EXPORTS OF RUBBER. l 



To Russia . . 2,205,205 1,860,362 2,858,843 



Germany 



Belgium 



France 



United States of America 



Other Countries 



3,342,715 1,690,972 



789,151 364,856 



1,876,506 1,294,656 1,772,100 



5,417,127 5,912,899 9,273,915 



1,205,900 996,528 2,060,638 



Total Re-Exports . . 14,836,604 12,120,273 15,965,496 



TRADE IN RUBBER GOODS 



1913 1914 1915 



Imports of Boots and Shoes, doz. pairs . 95,771 85,348 160,462 



value. 119,921 164,323 264,260 



Exports of ,, ,, doz. pairs . 132,736 121,681 118,716 



value. 138,006 123,756 139,340 



Imports Waterproofed Apparel . . 6,482 8,456 5,376 



Exports . 1,021,393 774,489 525,234 

 Exports other than above and Tyres and 



Tubes 1,656,246 1,178,128 1,061,540 



It has already been mentioned that rubber is obtained from 

 the milky juice or latex which exudes on wounding the bark of 

 the tree. The age at which the process of tapping should com- 

 mence is about four or five years, but this is dependent on 

 various considerations, and differs somewhat according to the 

 kind of tree and the climate and soil of the district, which affect 

 the rate of growth. Tapping is a process which consists in 

 scoring the bark by means of a gouge or some kind of knife with 

 adjustable blade, of which a large number of varieties have been 

 patented. In the plantations a vertical channel is often cut first 

 and a collecting tin placed at the foot. A dozen or more oblique 

 cuts are then provided to lead the juice into this channel. Various 

 other systems of tapping are adopted in different countries. 

 These are sufficiently indicated in the accompanying diagram 

 (Fig. 130) ; in connection with which it may be noted that the 

 half herring bone system is by far the most common. 



The latex as it flows from the tree has a tendency to coagulate 

 and to form clots or scrap which has to be dealt with separately. 

 But the bulk of the liquid is conveyed as soon as possible to the 

 factory, and after being strained, to remove impurities, it is 

 mixed with a small quantity of acid, generally acetic acid. A 

 clot soon forms which takes the shape of the containing vessel, 

 and after washing the rubber is passed through rolls, and then 

 dried. 



1 Prior to 1915 these figures include waste and reclaimed rubber as well as raw 

 rubber. 



