which results in the production of crepe rubber. Although at 
present neither clean biscuit, sheet, worm, nor crepe rubber need 
be washed for ordinary use, yet if washing and sheeting plantation 
rubber is to be dispensed with in the manufactory, it would be a 
great advantage when dealing with the larger quantities to have it 
ready in the washed and sheeted form, and the advantage of crepe 
over other forms would be most marked when dealing with many 
tons at a time. 
ADULTERATION OF WASHED RUBBER. 
8. There is one danger connected with the use of a washing 
machine on a plantation. By its means adulteration with inferior 
rubber, rubber substitutes, and recovered rubber, could be carried 
out without possible detection by eye or hand inspection, although 
chemical analysis or practical use of the rubber w T ould reveal the 
sophistication. In unprincipled and fraudulent hands such adul- 
teration might be carried to a considerable pitch before detection 
occurred, and this possibility of misuse should not be lost sight of 
by those who are responsible for the purity of the rubber pro- 
duced. 
ANALYSIS OF RUBBER. 
g. The chemical composition of rubber has no consideration 
either from the buyers or the manufacturers — the former base 
their valuation entirely upon the appearance, feel, smell, and ap- 
parent strength of the rubber when pulled about in their hands, the 
latter rely chiefly upon the way the rubber works upon their 
machines during manufacture, though in a few instances properly 
controlled and systematically carried out tests of tensile strength 
and elasticity are made with samples of the rubber prepared and 
vulcanised. The percentage amount of the impurity which is 
inherent in the rubber and which cannot be removed by wash- 
ing — that is, the oily, resinous, and nitrogenous, or proteid, 
impurity — is practically never determined in the factory, and a 
statement of these values with the rubber for sale would neither 
be understood nor attended to. In the present state of ignorance 
as to the influence of these ingredients upon the working qualities 
of the rubber during manufacture, the apathy with which varia- 
tions in their amounts in the raw material are regarded is natural 
and quite intelligible. 
PACKING. 
io. There are several points which must be remembered in 
packing rubber. Rubber at temperatures above 65°F. is naturally 
adhesive, and clean surfaces pressed into contact tend to stick to 
one another, though the rubber be dry and show no vestige of 
tackiness. Rubber during transit invariably shrinks in bulk owing 
chiefly to the action of its own weight in compacting the mass, and 
partly perhaps to a natural shrinkage of the rubber substance with 
the ageing of the rubber. Dust and grit which find way inside the 
cases adhere to the rubber. The care requisite in packing, there- 
fore, depends upon the form in which the rubber is shipped. If 
