1908\ 
Optical Rotation of Turpentine 
89 
from light and avoiding the filling of the pails with rain water. 
Every four weeks these pails were removed from the tree, tightly 
stoppered and immediately shipped to this laboratory for exami- 
nation . The specimens so obtained w T ere extremely pure and free 
from chips. After removal of the pails, the metal gutters were 
raised to a point near the shipping surface in order to minimize 
the amount of oleoresin which might stick to the exposed portion 
of the trunk above the gutters. 
The distillation of the oleoresins was carried out in a 500 cc. 
Kjeldahl flask, surrounded by a bath of cottonseed oil. Steam 
from a small boiler was first passed through a small iron pipe in 
which it could be superheated, then into the distillation flask 
through a glass tube having on its end a bulb containing a num- 
ber of openings. By this means strong agitation of the molten 
oleoresin was obtained. Thermometers were placed both inside 
the flask and in the oil-bath. The mixed vapors of steam and 
spirits of turpentine were passed through a Hopkins condensing 
bulb to prevent the carrying over of solid particles of resin, con- 
densed in an ordinary Liebig condenser and collected in a separa- 
tory funnel . After drawing off the lower layer of water, the spir- 
its of turpentine was transferred to a dry flask and allowed to 
stand over night with calcium chloride. The determinations of 
the optical rotation of the volatile oils were made with a Schmidt 
and Haensch half-shadow polariscope, sodium flame, at 20°. 
In the following table are given the results from the first collec- 
tion of the oleoresin in early spring : 
Tree 
designation Species 
Diameter 
(inches) 
Optical rotation 
100 mm. tube, 
Character of chipping 20 C 
A1 
P. heterophylla... 
... 7.0 
1st year, normal depth 
a u 
— 20°5O 
A2 
14.5 
-f 0°I5' 
A3 
24.5 
i i it 
—15° O' 
A4 
P. Palmtris 
. . 7.3 
a a 
+ 15°4CK 
A5 
“ 
15.0 
a a 
+ 8° 9' 
A6 
“ 
21.0 
u i l 
+ 18°18' 
Cl 
P. heterophylla.., 
... 12.3 
2nd year, shallow 
U t( 
—27° IP 
C2 
U 
8.2 
— 26°28' 
C3 
P. palustris 
... 13.0 
“ “ 
— 7°26' 
C4 
8.7 
ti n 
-f 7°3l / 
D1 
“ 
9.0 
2nd year, normal depth 
+ 10°50' 
D2 
“ 
13.5 
+ l°23' 
D3 
jP. heterophylla... 
... 13.0 
Cl n 
— 18°35/ 
D4 
a 
9.0 
a i i 
— 29°26< 
