MANILA COPAL. 201 



sistency with turpentine distilled from the resin of the Benguet pine 32 

 (Pinus insularis Endl.). A well-prepared strip of red narra wood was 

 given two coats of this varnish, and it has remained exposed in the 

 laboratory for a more than a year without any noticeable loss of dur- 

 ability or luster. 



CONCLUSION. 



The changes which take place during the cooking of varnish are 

 largely changes in the oil rather than the resin, i. e., it is possible so to 

 treat linseed oil, either by boiling or by adding to it linseed-oil acids 

 previous to its addition to the fused resin, that it will form a clear, homo- 

 geneous mixture with the latter which will remain so upon qooling, 

 without subsequent heating to temperatures greater than 150° to 200°. 



S2 This Journal, Sec. A (1909), 4, 231. 



