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all wild rubbers I do not say fine hard Para, but all wild 

 rubbers. 



Trie next point I want to speak of is the use of sodium 

 bisulphite. The use of this material is being very severely 

 " criticized in various quarters, and as I was largely responsible 

 for the introduction of sodium bisulphite, perhaps I may be 

 allowed to say a few words in defence of this much maligned 

 substance. Now in the first instance sodium bisulphite was 

 used in order to produce a rubber of paler and more even 

 colour. I want to emphasize the words " more even," because 

 it was not merely a question of paler, but of more even colour. 

 We are informed by Mr. Williams this morning, and shall no 

 doubt be told by many other manufacturers, that the question 

 of the colour of rubber is of no importance that a dark 

 rubber, as he said (and I agree), may be frequently much 

 better than a pale rubber, and that consequently it is a very 

 serious mistake for plantations to use chemicals, even mild 

 chemicals, for the preparation of rubber pale in colour, when 

 such pale colour is not in demand. Now the answer to that 

 is very simple. For quite a long while, and even to some 

 small extent to-day, pale, even-coloured rubbers fetched a 

 better price (it may have been only a halfpenny or a farthing 

 per lb., but still a better price) than dark-coloured rubbers, and 

 naturally enough the planters take means to produce rubbers 

 which fetch a better price in the market. 



Now I want to refer specifically to some experiments which 

 Mr. Williams quoted in reference to the use of sodium 

 bisulphite. Firstly, he stated that he had tried mixing small 

 quantities of sodium bisulphite with rubber, and vulcanizing it 

 with such admixture, and that he had obtained results which 

 tended to show that the bisulphite was extremely harmful. Mr. 

 Williams stated, I think, that the maximum amount of sodium 

 bisulphite found in plantation rubber was 0*5 per cent. I 

 hardly think he meant that, because I have frequently examined 

 bisulphite-treated rubbers for bisulphite, and have not detected 

 any, and hardly expected to. The bisulphite can only be 

 detected in the form of sulphate, and some allowance must 

 naturally be made for sulphate being present even in untreated 

 latex. I think, therefore, that possibly Mr. Williams's figures 

 require a little adjustment. Taking the result of these experi- 

 ments, I do not think it is a fair method and when I say I do 

 not think it a fair method, I do not suggest that any other 

 course was open to Mr. Williams, but I do not think it a fair 

 method to mix sodium bisulphite with rubber, and then to test 

 it against rubber untreated. It is very different mixing a salt like 

 that with crude rubber, to putting a dose of the salt into the 

 latex in solution. In this connection I want to revert specially 



