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have been sold in the London market, and practically no differ- 
ence in the selling price of the product of these three different 
trees has been discovered. It seems to me, however, that the 
value of plantation rubber has not been properly gauged in 
the different markets. Too much value nas been attached to 
the colour and appearance of the product, and too little regard 
paid to what one may call the physical properties of the product. 
I think if we could have some method of estimating the actual 
physical properties of the different kinds of rubber produced we 
should make a step forward, and therefore I am strongly in 
favour of standardization in some form, and of plantation 
rubber being bought and sold upon some test of that character. 
The variations in the colour of rubber do not seem to be 
important or essential, and it is very extraordinary to hear the 
statement of Mr. Williams that pale rubbers, pale Hevea 
plantation crépes are. not suitable for his work, and that he 
would avoid their use, whether they were treated with bisul- 
phite or not. It seems to me that a pale sheet or a pale crépe 
must ‘be better than some of the darker varieties, although a 
good many of the darker rubbers are equally as pure as the pale 
ones. The paleness is determined mainly by the colour of the 
water used in the washing and the thinness of the crépe; and 
even the palest crépes when bulked together look darker. 
Sometimes we find that a demand for very pale crépe has been 
met by making it thinner, although identically the same as the 
grade hitherto sold thicker. As to the use of sodium bisulphite, 
[ agree with what Dr. Stevens has said. It seems to me that 
Mr. Williams’s experiments were hardly fair on the use of 
that reagent. It should not be necessary to use bisulphite in 
order to produce the pale grade. I have used successfully on 
one estate formic acid instead of acetic acid, and have found 
that formic acid has the advantage over acetic acid of being 
itself a decided antiseptic; the quantity of formic acid used is 
not greater than that of acetic acid. Of course, coagulation, 
as pointed out by Dr. Schidrowitz, is determined by acidity, 
and therefore any acid can be used for bringing about 
coagulation. Formic acid, however, has the advantage of 
being distinctly germicidal, and it has the further advantage 
that if it does undergo any change it passes into carbonic acid 
and water, and there is no residue in the finished crépe. The 
small quantity of formic acid remaining in the crépe will 
prevent the growth of mould upon the surface. We have 
never used bisulphite at all, and have never been troubled with 
moulds, and therefore I think it is quite possible to produce 
a pale rubber without the use of bisulphite. It is difficult to 
see, therefore, why Mr. Williams and his company have such 
a strong objection to a pale-coloured rubber in the form of 
