ESSENTIAL OILS 
193 
» The determination of these constants enables us to classify 
oils into first and second grades. The limits for these grades 
are given in Table 32. 
TABLE 32.—Classification of ilang-ilang oil according to Bacon. 

| Constants. First grade. Second grade. 
RLIStErAAUINDeD = as as Soe Ree. 100 and above _______- 80 to 100. 
Index of refraction 1.4900 and below_-_--- Above 1. 4900. 
—45° and below __-___- Above—45°. 

| Specie TROGAEION >= ee eee ee eae ME 2 EMS Pee 
In a later publication Bacon showed that first-grade oils have 
1 higher acetyl number than second-grade oils. 
The classification of ilang-ilang oil now in use is a modifica- 
tion of Bacon’s standard of classification, which was proposed 
by Dr. Jaehrling of the firm of Santos and Jaehrling of Manila, 
and advocated by Gibbs.* The constants of this classification 
are given in Table 33. This classification divides Bacon’s first 
class into three divisions, namely: extra, l—a, and 1-b. This 
division is, apparently necessary on account of the large pro- 
portion of high-grade oil which is now produced. 

TABLE 33.—Classification of ilang-ilang oil according to Jaehrling. 













Index of Specific Solubility in 
4 Grade. Ester number. refraction. rotation. alcohol of— | 
Per cent. 
IOSgn eh 5 ee ete ro | Above 145 ____| Below 1.4900__| Above—35 ____| 80. 
ip Lee ANE Ae cae ee eee be ee 120to' 145-22- 1. 4900 to 1. 4950 |—35 to—48_____ 90. 
i) 0 8 I nee nee eo 100 to 120____- 1. 4950 to 1.4990 —48 to—60____- 90-96. 
> 7 
Ae ad So eS Oe, eee ae Below 100 ____| Above 1.4990 | Below—60 ._-_-_| 96 
ee 

The solubility of ilang-ilang in alcohol is also given as an 
extra test. 
According to Gibbs, this is very useful as a con- 
firmatory test, since it indicates the amount of sesquiterpenes 
present in the oil. This test consists in determining the lowest 
strength of aqueous alcohol which can be mixed with the oil 
without cloudiness, in the proportion of 2 of oil to 1 of alcohol. 
Bacon suggests an easy method of judging approximately the 
quality of an oil: 

* Gibbs, H. D., Proposed modification of ilang-ilang oil standards. Phil- 
*ippine Journal of Science, Section A, Volume 10 (1915), page 99. 
168837——13 
