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film which sometimes gives the rubber a wrinkled 
glossy appearance, especially in the depressions on 
a “ diamond ” marked sheet. When the sheet is 
stretched, the film is broken and appears as a brown 
rusty deposit. According to some Dutch scientists 
the film is caused by the bacterial decomposition of 
the serum products which exude and evaporate on 
the surface. 
Manufacture The manufacture of pale crepe by the 
of Pale use of sodium bisulphite to prevent 
Crepe. the normal or natural darkening of 
the rubber, which is otherwise caused 
by the action of the oxidising enzyme on certain 
substances almost invariably present in Hevea latex,, 
calls for no remarks. 
The detail connected with the preparation of this 
type of raw rubber has been so thoroughly mastered 
in most well run plantation factories that the product 
can be guaranteed to a very sharp standard of 
uniformity and appearance. That the consuming 
manufacturer of vulcanized goods is not materially 
benefitted by this elaborate care on the part of the 
producer seems to be particularly deplorable at a 
time when the British rubber world as a whole, and 
the planting community in particular, is so severely 
handicapped in all efforts towards the re-establish- 
ment of improved industrial conditions. 
Manufacture With the present ratio between pro- 
of Lower duction and consumption of rubber and 
Grades. the low market price of rubber, the 
only lower grade rubber which appears, 
to be worth preparing is that composed of the lump, 
washings and skimmings and picked tree-scrap,, 
which can be mixed and converted into one grade. 
