1 47 



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 crepes 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 crepe 

 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 crepe ; and 

 even the palest crepes when bulked together look darker. 

 Sometimes we find that a demand for very pale crepe has been 

 met by making it thinner, although identically the same as the 

 grade hitherto sold thicker. As to the use of sodium bisulphite, 

 I 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 crepe. The 

 small quantity of formic acid remaining in the crepe 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 



