Ill 
The problem therefore with whieh we have to deal in connection 
with the preparation of first grades, is whether we are going to be 
content to produce pale crepe and smoked sheet as carried on at 
present or to endeavour to substitute another and an improved type 
of rubber in place of smoked sheet and it is this problem primarily 
with which I propose to deal briefly, leaving the subject open for 
discussion, after bringing forward the salient facts in support of a 
new method of preparation. 
It -would probably be preferable to state at once that the 
proposed method of manufacture is that which we have styled 
“ slab ” rubber, in lieu of sheet. 
Our researches have shown that whereas smoked sheet cures in 
about 2| to 2f hours under the conditions employed, “ slab ” rubber 
cures in about If hours or less than half the time. Apart from this, 
“ slab ” rubber is about 20 to 25 per cent, superior in tensile properties 
to crepe and generally superior to smoked sheet. The advantages to 
the rubber manufacturer of this type of rubber are therefore obvious. 
Whether a manufacturer would be prepared to pay a premium for such 
rubber however remains to be seen and for the present it is taken for 
granted that such rubber would merely fetch the ordinary top market 
prices obtained for smoked sheet. We, therefore, have to consider its 
preparation entirely from the producer’s point of view (assuming of 
course that it is not going to fetch a lower price on the market, as 
it probably would do if judged by appearance only). What are the 
advantages we must ask ourselves of any alteration of existing 
methods. Some planters may be very, conservative in this respect 
and prefer a laissez-faire policy, but I venture to suggest that, 
especially at this time, we have no more right to adopt such a policy 
in our commerce and industry than we have in the conduct of our 
military affairs and I therefore assume that all planters are alive to 
the necessity of a change if it can be shown that such a change will 
produce an improved product. 
We have now to consider the possible forms in which such a 
type of rubber can be prepared, taking note of the advantages and 
disadvantages of each method of preparation. 
There are only three possible forms in which such rubber could 
be prepared for the market, viz. (1) virgin “ slab ” containing about 
20 per cent, of moisture, (2) in the form of crepe, (3) in the form of 
dry block. 
Of these forms the most suitable when everything is taken into 
consideration, is the first. T'he only disadvantage of shipping virgin 
“ slab ” is that extra freight has to be paid on about 20 per cent, of 
water. 
The pre-war freight on rubber was about \d. or say 2 cents 
per lb., while the present rates are about Id. or say 4 cents per lb. 
