24 PHILIPPINE RESINS, GUMS, AND OILS 



surface, and the resulting resin is generally mixed with chips 

 of bark. 



When the resin first exudes from the tree, it appears as almost 

 colorless tears, the outer surfaces of which soon harden. As 

 exudation continues, the fresh resin instead of flowing out over 

 the first portion produced appears to force the latter outward by 

 being deposited beneath it. The outer surfaces are thus always 

 hard and friable and the. inner portion hardens very slowly. 

 About two weeks are required to produce solid pieces of market- 

 able size. 



The Manila copal which is exported from the Philippines 

 directly to the United States is cleaned, sorted, and graded in 

 Manila. Particular attention is paid to cleanliness, color, and 

 size. Manila copal is sometimes adulterated with other resins, 

 particularly dipterocarp resins; the latter, however, are very 

 readily distinguished from Manila copal. As the resin is col- 

 lected largely by non-Christian tribes, the sorters in Manila 

 frequently encounter considerable admixtures of other resins, 

 and as the consumers have to depend largely on Philippine 

 sorters, it is not surprising that the securing of a uniform quality 

 of resin is a matter of some difficulty. 



ANALYSIS OF MANILA COPAL 



Almaciga has been the subject of a number of investigations 

 by the Bureau of Science.* 



Richmond examined recent surface and fossil (mineral) resin 

 to ascertain the probable composition and character of these 

 substances. The acid value was determined by dissolving ap- 

 proximately one gram of powdered resin in 50 cubic centimeters 

 of absolute alcohol and titrating with a half-normal solution 

 of alcoholic potassium hydroxide, using phenolphthalein as an 

 indicator. A gram of surface resin required approximately 

 128 milligrams of potash for neutralization, while a gram of 

 mineral resin required about 110. 



The saponification value was determined in the following 

 manner: — About one gram of resin was dissolved in 50 cubic 

 centimeters of absolute alcohol. Twenty-five cubic centimeters 



* P'oxworthy, F. W., The almaciga tree: Af/athis alba (Lam.), Philippine 

 .lournal of Science, Section A, Volume .5 (1910), pages 173 to 175. 



Richmond, G. F., Manila copal. Philippine .Journal of Science, Section 

 A, Volume 5 (1910), pages 177 to 201. 



Brooks, B. T., The destructive distillation of Manila copal. Philippine 

 Journal of Science, Section A, Volume 5 (1910), pages 203 to 217. 



Brooks, B. T., The oxidation of Manila copal by the air. Philippine 

 Journal of Science, Section A, Volume .5 (1910), pages 219 to 227. 



