36 RUBBER 



Presently we espy quite a number of donkeys coming 

 leisurely along towards us over the plain. They have 

 been down to a packing-shed close by with a load of 

 guayule, and are now returning for another load. 

 When they reach the harvest-field, great bundles of 

 the shrub are piled up on their backs, until we can 

 hardly see anything of the useful little beasts but a 

 row of heads and an array of paws. However, their 

 burden is not so heavy as its bulk would have us 

 imagine. We follow the caravan of donkeys to the 

 packing-shed and see them unloaded. Then we watch 

 the guayule being pitched by hand into crates and 

 tightly jammed therein by being jumped on by the 

 packers. When the bales are taken out of the crates 

 they remind us of trusses of hay. The bales are 

 weighed, stacked in carts, and taken to the factory. 



Seated on a bale in one of these carts, we, too, go to 

 the factory. Here we see the crop of guayule being 

 crushed between rollers, and for the moment we are 

 reminded of a sugar-mill. The crushed plant, a 

 mixture of bits of wood and atoms of rubber, is con- 

 ducted to a pebble-mill, which is a drum half filled with 

 stones and water. The mill is rotated, and the rubbing 

 action which is thus set up rolls the rubber into larger 

 pieces and grinds the wood to pulp. 



The mixture is now pumped into large tanks. The 

 rubber, being lighter than water, floats ; the wood, 

 being heavier, sinks. The rubber is skimmed off and 

 purified, after which it is washed and put into bags 

 ready to go to market. 



Guayule rubber is of sufficiently good quality to be 

 used for all but the highest class rubber goods, such as 

 surgical appliances. 



