54 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 half- 
way 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 ultimate 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 + 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 
removed 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° . 
30° =(0.9127. Siena 
* Bacon, R. F., Philippine terpenes and essential oils, III. Philippine 
gournal of Science, Section A, Volume 4 (1909), page 93. 
+ Clover, A. M., Philippine wood oils. Philippine Journal of Science, 
Section A, Volume 1 (1906), page 195. 
timeters, 30°). The specific gravity was 

