48 CAOUTCHOUCS OR INDIA RUBBERS (Ceard). 
coagulate there. Hence the rubber contains large quantities 
of dirt on its lower surface, which is removed to a certain 
extent by rubbing in coarse-meshed sieves, (c) By smoking 
with the vapour from the burning nuts of a palm, in a 
similar manner to Para rubber. So prepared, it contains a 
large quantity of water, which partially sweats out on 
exposure to the heat of the sun. The exudation on evapora¬ 
tion leaves a brown resinous substance. This last method is 
becoming very general. 
“ To collect the latex small tin cups are used ; each tree 
is tapped eighty days, divided by an interval of about three 
months into two periods of forty each. Under this system 
the tree is said to live for fifteen to twenty years. 
“ The tapping is always done in the dry season, from July 
to December. 
“ The average yield per tree is from to 1^ kilos (1 to 3 lb.) 
per year ; coagulation may be effected by churning or by 
the addition of an excess of water or salt solution. In the 
former case the rubber particles, which are unprotected by 
any film (as the fat particles of milk are), simply adhere to 
form a mass. 
“In the case of the addition of excess of water, salt, or 
smoking, coagulation is brought about by means of the 
globulin present. This coagulates at 74-76° 0. or on 
dilution, &c., and tangles up the rubber particles in its 
meshes, much as white of egg gathers up particles in sus¬ 
pension when used for clearing jellies.” 
The first important trial in Ceylon was made at Peradeniya 
in dry weather at the end of April, 1882, when the trees were 
five years old. The dry bark was peeled off, and sloping cuts 
were made with a knife. The milk mostly dried on the 
stem, and was pulled off and rolled into balls (sample 1), 
but some fell on the ground and became mixed with sand, 
and was also more sticky than the rest (sample 2). The 
milk was found to flow most freely in the early morning. 
