140 
Now I do not differ from Mr. Williams on any essential 
point, except perhaps in regard to the conclusion as to which 
grade is most homogeneous, which grade is the least variable, 
and which grade is most satisfactory. Mr. Williams has told 
us that they have abandoned any rubber except ordinary sheet 
and biscuits, and yet he tells us that quite recently they had to 
alter their heats very considerably—I presume in regard to 
those particular grades, though perhaps I am wrong as to that. 
I take it that Mr. Williams’s reply to that would be that even 
these variations are less than the variations of the other grades. 
Now, so far as my own particular experience goes, it is that 
smoked sheet shows the smallest variation in regard to rate 
of cure, also in regard to tensile properties, and also in regard 
to, general mechanical properties. I agree with Mr. Williams 
that plain sheet is about the best rubber produced when it is 
good; but my experience, based on a considerable number of 
samples is, that it varies a great deal more than does smoked 
sheet. Thus, of some fifty samples, half of which were smoked 
sheet and half ordinary plain sheet, which were examined, the 
difference in rate of cure on a single standard basis was: 
smoked sheets, from one and a half hours to two and a half 
hours; plain sheets, from one hour to over four hours. In 
fact, there was one in the latter series which was almost uncur- 
able under the standard basis. At the same time, the best 
sample of plantation rubber I have ever had, I think, was plain 
sheet, and perhaps Mr. Williams and the North British factory 
have been particularly successful in selecting a very good grade 
of plain sheet. I may say here that a factory such as the North 
British, or one or other of the great factories in this kingdom, 
is naturally in a position of great advantage as compared with 
small manufacturers who cannot have an elaborate scientific 
testing department; and, as Mr. Williams has well pointed 
out in his article in the Rubber Exhibition handbook : — 
‘‘ These troubles, in factories where scientific control is not 
thoroughly organized, may be sufficient to condemn the use of 
this grade entirely.’’ 
I think, Sir, it is for this reason that the plantation interest 
should work from every point of view for the purpose of 
diminishing variability. In making this statement I refer 
first of all to the work of the planter and the work of the 
chemist at the other end, and to the work of the manufacturer 
and the technologist at this end. I refer, in fact, to the 
question of standardization in its broadest aspects. In making 
this statement, I wish it to be clearly understood that when 
we refer to the variability of plantation rubber, particularly 
as compared with wild rubber, there is no intention to cast 
a great big stone at plantation rubber at all. The best 
