56 PHILIPPINE RESINS, GUMS, AND OILS 



BALAU (APITONG) RESIN 



Oil obtained from the trunk of this tree is known as balau, 

 and is used locally as an illuminant, for varnishing, and for 

 caulking boats. Balau resin used as a varnish produces a very- 

 brilliant, tough, and durable coating, and according to Bacon * 

 seems to have properties that would make its general use for 

 varnish manufacture desirable. It has, however, the serious 

 disadvantage of drying very slowly and, in its original state, 

 has not yet been successfully combined with linseed oil or other 

 dryers. Bacon, by distillation, obtained a hard, yellow, lustrous 

 resin soluble to the extent of about 75 per cent in alcohol or 

 turpentine, the solutions giving hard, lustrous varnish coatings. 

 This resin dissolves completely in two volumes of linseed oil and 

 two of turpentine, giving a varnish which dries slowly (five 

 days) to a tough, hard coating. 



Balau is collected by chopping into the tree and making a 

 cavity where the oil can collect. Often the cuts extend halfway 

 through the trunk. The flow may amount to more than a kilo 

 per day. It is customary to remove the resin every few days 

 and to apply fire to the cuts at frequent intervals. It is reported 

 that the same tree can be tapped for a number of years. Tapping 

 usually results in the entrance of decay organisms and the ul- 

 timate death of the tree. For this reason all trees which are 

 tapped for balau should be cut and used for timber before the 

 wood is destroyed. 



Balau is a thick fluid when fresh, but hardens after long 

 exposure to a semi-plastic condition. The total recorded pro- 

 duction in 1917 was 54,080 kilos. 



According to Clover f balau consists of a solid resin, water, 

 and a volatile oil which is present to the extent of about 35 

 per cent. Balau has a feeble, characteristic odor and dissolves 

 in the usual organic solvents except alcohol. The water which 

 the oil contains appears to be chemically combined and is not 

 rem'6ved easily by distillation. When distilled directly, all the 

 water and a portion of the oil passes over below 260°. A sample 

 was distilled under diminished pressure (40 mm.) at 151° to 

 154°. The optical rotation of this fraction was 78°. 5 (10 cen- 



30' 

 timeters, 30°). The specific gravity was „- =0.9127. It had 



* Bacon, R. F., Philippine terpenes and essential oils, III. Philippine 

 Journal of Science, Section A, Volvune 4 (1909), page 93. 



t Clover, A. M., Philippine wood oils. Philippine Journal of Science, 

 Section A, Volume 1 (1906), page 195. 



