MACHINERY AND MANUFACTURE 



195 



be first passed twice through the macerator and then through 

 the " Universal " washing-machine. In this way a very 

 thorough cleansing is ensured. If put through the washing- 

 machine first a lot of dirt remains in the rubber, as while the 

 rollers of the macerator can tear up the rubber and release the 

 embedded dirt the washing-machine cannot do this effectively. 

 On the other hand, the washing-machine, in addition to the 

 macerator, removes a great deal of dirt which would be still 

 left in the rubber unless it were laboriously put through the 

 macerator an impossible number of times. Scrap and other 

 rubbers treated in this 

 way fetch a good price, 

 which amply repays 

 the additional labour 

 spent on them. 



A number of well- 

 informed people take 

 the view that if it 

 were not for the re- 

 quirements of scrap- 

 rubber, bark-shavings 

 and earth-rubber, it is 

 probable that in a year 

 or two we should find 

 only finisher-mills in 

 the factory to prepare 

 sheets for smoking. The future factory, it is thought, may 

 have no creping mills, and a change of this sort may very 

 well come about. 



The question of how best to grade the rubber deserves very 

 careful consideration by rubber-growers. Practice varies a 

 good deal in regard to this matter. Some have advocated as 

 many as five grades of rubber, namely, first-latex, lump-rubber, 

 scrap-rubber inclusive of the cup-washings bark-shavings 

 and earth-rubber. This is quite too long a list and the quantities 

 of some of these would be quite small and troublesome to keep 

 apart. 



Generally speaking three grades should be quite sufficient 

 for all purposes. Certainly the strained latex should be the 

 standard for first-grade rubber. If the lump-rubber, after it is 



FIG. 53. The " Universal" Washing-machine, 

 with Trough and Rollers tilted. 



