1908 ] 
Volatile Oil of Pinus Skrotina 
103 
Temperature 
Per cent, 
distillate 
Index of refrac- 
tion, 20° 
Rotation in 100 
mm. tube 20° 
172-175° 
27.4 
1.4716 
— 87°53’ 
175-180° 
57.0 
1.4724 
— 92°21’ 
180-185° 
8.4 
1.4744 
— 92°14’ 
185— f- 
7.2 
1.5045 
Repeated fractionation at atmospheric pressure showed some 
polymerization. From a fraction, 175-176°, a large yield of lim- 
onene tetrabromide was obtained. Melting point 103°-103°. 
The solution of the tetrabromide in chloroform was levo-rotatory, 
— 70-0°. 
A study of the oxygen absorbing power of this volatile oil in 
comparison with that of the ordinary spirits of turpentine 
obtained from P. palustvis showed a much larger absorption by 
the oil of P. serotina during the early days of the experiment, but 
the total absorption after three months’ exposure to northern 
light was practically the same in each. 
These results show a wide variation in the optical rotation of 
the volatile oils from the individual trees, even among trees of the 
same species. In a general way the figures give support to Long’s 
view, namely that the volatile oils from the Pinvs palustris are 
dextro-rotatory and those from Pinvs heterophylla levo-rotatory. 
That this is not strictly true, however, is evidenced by the dextro- 
rotation of A a (P. heterphylla ) and more especially by the levo- 
rotation of C 3 (P. palustris). 
University of North Carolina 
Chapel Hill, N. C. 
