194 



PHILIPPINE RESINS, GUMS, AND OILS 



and ready for pollination. No doubt, in the course of time much can be 

 done toward improving the yield and quality of ilang-ilang oil by intel- 

 ligent plant selection. Such work requires much patience and at present 

 there are absolutely no data available save a general opinion that the 

 ilang-ilang trees of the wild mountain regions are not as fragrant as the 

 cultivated ones of the lowlands. 



CLASSIFICATION OF ILANG-ILANG OIL 



It is a well-known fact that ilang-ilang oil, like many other 

 natural perfumes, does not owe its fragrance to any one sub- 

 stance, but is a mixture of a number of odoriferous compounds. 

 It is generally bought and sold on the judgment of the dealers, 

 the determining factor being the odor. Obviously the judgment 

 of various buyers may differ, and consequently it is desirable, 

 if possible, to value the oil according to analytical tests, so that 

 the purchase and sale may be placed upon an exact analytical 

 basis. 



Bacon obtained a number of samples of ilang-ilang oil, mostly 

 from one distillery, the process of distillation being watched and 

 the samples collected by himself. He determined a few of the 

 simple constants of these oils, such as specific gravity (pykno- 

 meter) , optical rotation, refractive index, and ester number ; the 

 latter by the usual method, using 1 gram of oil. A few of these 

 results are recorded in Table 31. 



Table 31. — Tabulation of the constants of ilang-ilang oils. 



