192 
necessary to make a cavity in the trunk. Botanical specimens of the 
tree from which the sample under consideration was taken accompanied 
it and they were identified by Mr. Merrill, of this Bureau, it being the 
species given above. The oil is quite mobile, perfectly homogeneous, light 
yellow in color, with a slight fluorescence and a feeble but characteristic 
odor. 
" 
Specific gravity, ae = 0.9202. Optical rotation, —31°.3 (10 centimeters, 30°). 
When cooled below 20° it begins to deposit white, flaky crystals; these increase 
in amount as the temperature is lowered. The crystals are those of a hydro- 
carbon, melting at 63° to 64°, and occurring in the oil to the extent of a few per 
cent. The oil completely dissolves in all the ordinary solvents, excepting alcohol, 
which causes the separation of the white crystalline hydrocarbon already referred 
to. Oil of Supa takes up oxygen slowly from the air and finally hardens, several 
weeks being necessary for the drying of a thin film. 
Volatile portion—When Oil of Supa was subjected to steam distilla- 
tion, a colorless oil was slowly carried over, the process being continued 
until most of the latter products had been removed. On allowing the 
distillate to stand until it was perfectly clear it showed a rotation of —21° 
.(10 centimeters, 30°). It was impossible to obtain a constant-boiling 
product from the latter upon fractioning under diminished pressure. At 
40 millimeters nearly all of the oil passed over between 148° and 149°, 
the residue apparently being as fluid as the distillate and indicating no 
polymerization. The distillate had a specific gravity of (=) 0.9053 and 
when redistilled it boiled between 255° and 267° (760 millimeters) with 
practically no residue. In order to save time it was found to be more 
convenient to remove the volatile oil by direct distillation under reduced 
pressure. With a pressure of 40 millimeters the temperature of the dis- 
tillate gradually rose to 170°, at which point nearly all of the volatile 
portion was removed, the total quantity in the receiver consisting of 
about 73 per cent of the original sample, and containing only a slight 
amount of water. The residue was light brown in color and became 
semisolid on cooling; it dissolved in all the ordinary solvents, excepting 
alcohol, which separated the solid hydrocarbon referred to above. The 
distillate was colorless and practically remained so on standing in a 
closed vessel. It had the feeble, but characteristic, odor possessed by the 
steam-distilled oil, and on refractioning at 40 millimeters it almost com- 
pletely passed over within 7°. No low-boiling substance was noted, and 
after repeated distillation it was not found possible to obtain a much 
more constant-boiling product. The oil probably is a mixture of sesqui- 
terpenes, as cadinene was proven to be present. The absence of bodies of 
an alcoholic nature was demonstrated by the fact that neither sodium 
nor phosphorus pentoxide in benzol have any action on the oil. On 
passing hydrochloric acid gas into a solution of the distillate in acetic 
