RUBBER AND RUBBER PLANTING 221 



canvas into the various articles which are being made 

 in the factory. Vulcanisation is subsequently carried 

 out by steam heat in moulds or presses or closed 

 chambers. Certain other articles again are cut out of 

 rubber already vulcanised. 



Washing. 



It has already been pointed out that in dealing with 

 the pure samples of rubber now produced on estates, 

 the preliminary cleansing operations, necessary in the 

 case of all ordinary commercial samples, will probably 

 be omitted from the series of manufacturing processes 

 in the rubber factories of the future. The washing 

 machines used in factories are generally similar to those 

 employed upon estates, but are usually larger and more 

 powerful. They are generally driven from shafting 

 through powerful clutches, and special arrangements 

 are often introduced for throwing the machinery auto- 

 matically out of gear in case of accident, for example 

 when large stones or other bodies liable to cause damage 

 are encountered. Prior to the actual process of washing, 

 large commercial blocks are softened by soaking in hot 

 water, and are sliced into smaller pieces by special 

 machines, either before or after the softening process. 

 A series of washing machines is usually employed, and 

 the rollers through which the rubber first passes have 

 coarser grooves and are set further apart than the later 

 members of the series. The arrangement thus resembles 



