22 PHILIPPINE RESINS, GUMS, AND OILS 



True copals are hard, lustrous, yellow, brown, or nearly white, and 

 more or less insoluble in the usual solvents, but are- rendered soluble by 

 melting before making into varnish. 



The copals are resins which contain those very permanent 

 substances known as resenes. 

 Bottler and Sabin * state that : 



* * * they contain, moreover, ethereal oils, which are driven oif by 

 melting or distillation, a bitter principle, and coloring-matter. Zanzibar 

 and Cameroon copals consist mainly of resin acids and resenes; * * * 

 Manila is composed mostly of i-esin acids; but it contains more resene (12 

 per cent) than does Zanzibar (6 per cent). * * * 



Bottler and Sabin t further say : 



For making spirit copal varnishes only such copals can be used as will 

 readily dissolve to a clear solution, free from slimy or stringy qualities. 

 Manila and Borneo copals are used, the soft Angola and the newer Sierra 

 Leone. 



These varnishes may be made by such formulas as the following: 



Parts. 



(a) Manila copal 16 



Venice turpentine 4 to 5 



Alcohol (95 per cent) 30 



The resin of Agathis alba is found in the bark, and oozes out 

 whenever the latter is cut (surface resin). Occasionally lumps 

 of resin are found in the forks of branches, and large masses, 

 the so-called fossil (mineral) resins, are found in the ground. 

 These deposits are located by sounding the ground with sharp- 

 pointed sticks. Such resin is often discovered in places where 

 large trees have formerly stood, which have long since died 

 and decayed, leaving large masses of resin in the ground. 



According to Richmond, t more than 50 per cent of the Manila 

 copal exported from the Philippines is collected in the Davao 

 district of Mindanao, and probably 90 per cent of the resin pro- 

 duced in that region is obtained by blazing living trees. The 

 best results are secured by removing, from different sides of 

 trees, strips of bark about one meter in length and 20 to 30 

 centimeters wide, thus providing clean surfaces on which the 

 resin is deposited as it oozes from the cut end of the bark. The 

 resin is also obtained by means of a wedge-shaped incision in 

 the tree trunk. This method however does not provide a clean 



* Bottler, M. and Sabin, A. H., German and American varnish making 

 (1912), page 13. 



t Bottler, M. and Sabin, A. H., German and American varnish making 

 (1912), page 131. 



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

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



