112 
is immaterial, as far as the keeping quantities of the rubber 
are concerned, whether the entire moisture or only part of 
it is removed, as the moisture enclosed in the rubber is 
free from live putrefactive germs and can do no harm. 
Rubber prepared by this method both in the Amazon 
District and in Ceylon has proved to be equal to the best 
para sorts. Goods made from Purub prepared rubber 
appear to have superior keeping properties. There was no 
difference at the time of manufacture between goods made 
from Ceylon rubber prepared in the usual way with acetic 
acid and goods made from Ceylon rubber prepared by the 
fluorine treatment, but after 1J years the material prepared 
with fluorine showed much more elasticity than the other. 
Dr. Frank and Dr, Marckwald have examined this charac- 
teristic and believe the difference arises in the vulcanisa- 
tion. Purub rubber, they say, may be vulcanised extremely 
quickly. Added lead oxide was not sulphurised. In fact 
the rubber takes up the sulphur more" quickly than a chemi- 
cal combination between lead-oxide and the sulphur can be 
completed. It may be taken as fairly certain that rubber 
coagulated by Purub exhibits particularly good properties 
in manufacture. 
There has been references to Purub in recent numbers 
of the “India Rubber Journal’ ’ arising out of a summary 
of a lecture on the material by Dr. Frank at the Rubber 
Exhibition. From these we gather that it would be wise 
for any Planter who gives Purub a trial to indicate clearly 
on his* rubber that Purub has been used as a coagulator. 
One writer records a case where a parcel of rubber gave 
trouble because it vulcanised too quickly. A manufacturer 
who buys a sample of Purub-cured rubber under the im- 
pression that it has been cured in the acetic acid may suffer 
confusion and loss. Besides indicating that Purub has 
been used it will give manufacturers an opportunity of 
estimating its value. M. Victor Herin has shown that even 
“slight differences in the method of coagulation affect not 
only the strength and elasticity of the raw rubber but also 
such properties as its solubility in benzole.” 
If all the advantages claimed* for Purub are true it is 
certainly a superior coagulator. It is at any rate well 
worthy of a trial. 
W. J. Gallagher. 
