84 



g. Another reason of variation may be caused by mixing the 

 latex of trees of different age and size. It is frequently asseited 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 -liber 

 of Trees 

 Tapped. 



90 

 120 

 100 



Aggregate 1 

 girth at 3 



ft. from ! 



ground. 



Number 

 of times 

 tapped. 



Fluid Dry 



oz. of weigiit 

 latex, of rubber. 



220' 5" 

 276' 10^" 



276' lOi" 



Ratio of I 



fluid to ' Including 

 ozs. some added 



Adoir- I water. 



dupois. / 



3,511 

 3.433 

 3>98r 



37 lbs. 

 43 „ 

 48 „ 



Nov.-Dec. 



Oct.-Nov. 

 Sept. 



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 re- 

 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. 



11. 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 



