194 PHILIPPINE RESINS, GUMS, AND OILS 
* * * To prepare a 1 per cent solution of the oil in alcohol and* 
compare the odor with a similar one of an oil of known quality, as judg- 
ment is much more certain as to the perfuming power when dilute solutions 
instead of the pure oils are used. One cubic centimeter of each solution 
can then be poured on separated pieces of bibulous paper, the odor being 
compared at the end of twelve, twenty-four, or even a longer number of 
hours; this test gives some idea in regard to the permanence of the odor. 
DISTILLATION OF OIL IN VACUO 
Bacon found that the distillation of the oil 7n vacuo provides 
a good method of ascertaining the quality of an oil and the num- 
ber of flowers used in preparing it. He also showed that the 
rectification of oils in vacuo is not very successful. These points 
are shown in the following quotation: € 
* * * the rectification of oils im vacuo is not an entire success, as 
the distillates, although apparently of the same composition as the oil 
from which they are distilled, seem to lack in perfuming power; this is 
especially true of the lasting qualities of the odor. These results suggest 
that the highest boiling parts of the ilang-ilang oil and even the resins, 
are very probably important constituents of the whole, possibly they help 
to fix the more volatile, odoriferous portions. I have always been im- 
pressed by the peculiarly lasting fragrance of the resinous residues of the 
distillation of ilang-ilang oils fractioned in vacuo. 
The distillation of ilang-ilang oils in vacuo has shown that over 50 per 
cent of the first quality oil will pass over below 100° at 10 millimeters 
pressure, and when I have tested poorer oils in this respect I have found 
the amount of substance volatile below 100° at 10 millimeters which 
passed over to be proportional to the quantity of flowers used in preparing * 
the oil. Thus one oil distilled from flowers at the yield of 1 kilo for 206 
kilos of flowers showed 27 per cent of volatile constituents under the con- 
ditions named, whereas another prepared in the proportion of 1 kilo to 
150 kilos of flowers gave 19 per cent. 
It follows from this that the distillation test is also of value’ both in 
determining the quality of an oil and the proportion of flowers used in 
preparing it. The only manner in which poor provincial oils may be 
improved is by redistillation with steam, and this procedure results in 
large losses. Fractioning with steam in vacuo also seems quite promising, 
-although the process is very slow. Oils thus obtained are quite colorless, 
and by taking suitable fractions a very fair oil may thus be prepared from 
a product which before treatment was almost unsalable. 
7 
EXTRACTION OF PERFUME OIL WITH SOLVENTS 
Bacon * also studied the problem of extracting the oil from 
ilang-ilang flowers with solvents: 
* * * Many of the constituents of essential oils are very delicate 
substances and distillation with steam SEBUM HOS SS these compounds to a 
* Bacon, R. F., pions ae and essential oils, III. Philippine , 
Journal of Scienes: Section A, Volume 4 (1909), page 129. 

