84 
« 
g. Another reason of variation may be caused by mixing the 
latex of trees of different age and size. It is frequently asserted that 
there is no difference in the latex from trees of different age— a state- 
ment which could not be supported by fact. Under normal conditions 
the water contained in latex may vary from 55° to 65°. It may however, 
in very wet weather and with young trees, contain a much higher 
per centage as is shown in the following experiments : 
Table 4. 
SMALL TREES. 
Nu Tiber 
of Trees 
Tapped. 
Aggregate 
girth at 3 
ft. from 
ground. 
Number 
of times 
tapped. 
Fluid 
oz. of 
latex. 
Dry 
weight 
of rubber. 
Ratio of 
fluid to 
ozs. 
Adoir- 
dupois. j 
Including 
some added 
water. 
90 
220' 5" 
24 
3,5ii 
37 lbs. 
cia 
-> ie 
Nov.-Dee. 
120 
276' lOf" 
26 
3433 
43 » 
. 4ilr 
Oct.-Nov. 
100 
276' 10T 
28 
3,981 
48 „ 
5w 
Sept. 
310 
774 2*"' 
26 (average) 
10,925 
128 lbs. 
Total small trees. 
LARGE TREES. 
150 
71.3' 41" 
30 
18,748 
lbs. ozs. 
251 8 
4 % 
Nov.-Dee. 
It may be noted that the diversity is greater in the resulting 
rubber than in the volume of latex from young and old trees 
10. Considering the variability of latex which has been referred 
to, and the objection of manufacturers to the same cause in the le- 
sulting rubber, such results are not astonishing when the system of 
treatment is examined. In Malaya all the latex obtained is coagu- 
lated by some chemical re-agent, usually Acetic acid, and as will be 
evident by glancing at Table 4 different results were obtained from 
approximate volumes of latex in three experiments, while almost 
double the weight of rubber was obtained from a less area of bark in 
another experiment. If therefore, in one instance a given quantity 
of Acetic acid is necessary to precipitate one pound of dry rubber 
from one gallon of latex, in another instance the same quantity of 
acid would be used to precipitate double the weight of resulting 
rubber. The most that could be claimed for such a system is that it 
is an empirical one. 
XX. It should be observed too, that Acetic acid is far from being 
a perfect re-agent— unless an inordinate quantity of acid is used—there 
is always some water left, which, if again treated with Acetic acid will 
precipitate more coagulated latex 
