196 THE RUBBER TREE BOOK 



thoroughly washed and rolled out, is found to closely correspond 

 in appearance with the first-latex, then the sheets may be added 

 in among the first quality. Unless, however, the lump-rubber 

 sheets are found to be quite equal in quality and appearance, 

 which will rarely be the case, they should on no account be 

 added to first-quality rubber. The quantity of this rubber as 

 a rule is not and should not be great, and might, if added to 

 first-latex quality, if it was inferior, drag down the standard 

 and diminish the price obtained for the whole, thus involving 

 a far greater loss than if kept as a second grade, or even added 

 to the scrap-rubber quality. 



While there may be some dispute as to whether lump -rubber 

 should, or should not, be in a first or second grade, there should 

 be no question but that scrap-rubber, cup-washings and bark- 

 shavings should be ultimately united to form a secondary grade. 

 They ought not to be united at first. The bark-shavings are 

 better to be first steeped by themselves, and, when softened, 

 ground up in the macerator to get rid of most of the bark itself. 

 The scrap-rubber should also be separately passed through the 

 macerator twice. Thereafter, if there is a " Universal " 

 washing-machine in the factory and no large factory 

 should be without one the two can be united in the 

 washing-machine and freed from nearly all remaining dirt, 

 preparatory to being sent down again to go through the 

 mills and emerge finally as either second or third grade, as 

 the case may be. 



The earth-rubber is usually so exceedingly dirty that it is 

 better kept apart and considered as a low-grade rubber. Even 

 when treated in a " Universal " washing-machine it is more 

 than doubtful that it does not lower the quality of other grades 

 if mixed with them. 



Whatever number of grades may be decided on, the great 

 endeavour of the manager should be directed towards securing 

 regularity of colour and, above all, of quality. 



When manufacturing crepe-rubber the manager's great 

 effort should be to attain and maintain the highest possible 

 percentage of first-latex rubber. To ascertain what progress is 

 being made in this desirable direction, statistical sheets should 

 be kept up-to-date in the estate office as well as by the secre- 

 taries at home. These sheets should show the weekly output 



