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real quality of the raw material, or that certain 
so-called defects are in any way indicative of inferior 
quality. For example, the defect known by the 
brokers as “ rust ” on smoked sheet is certainly not 
connected with any inferior quality in the raw 
material, while the treatment of lower-grade rubber 
such as lump, cup washings and tree scrap with 
solutions of sodium bisulphite and sulphuric acid 
in order to obtain a rubber of paler and more even 
colour undoubtedly lowers the quality, although such 
rubber obtains a better market price on account of 
its appearance. 
Further, much pale-coloured native sheet, probably 
prepared by the use of alum, is converted into 
blanket crepe in Singapore and fetches a higher 
price than the darker native sheet which is coagu- 
lated with acetic acid and which, on conversion into 
blanket crepe, has a darker colour. In this case 
intrinsic quality is certainly not correlated with the 
appearance. The only point which concerns the 
individual producer at the present time in connection 
with the preparation of the raw rubber, is the 
appearance of the rubber and its superficial valua- 
tion by the broker. For some time past, nearly all 
samples received for investigation have been sent 
on account of such defects in appearance as bubbles, 
“ rust,” streakiness or dullness in crepe, yellow 
colour of pale crepe, “ spot ” disease and a few others. 
Considerable information is now available in con- 
nection with the causes of, and remedy for, all 
these defects. A good superintendent of the estate 
factory, who is capable of applying advice given in 
written instructions or in the literature already 
published, should be capable of dealing with these 
problems. 
