22 
Indian Forest Records. 
[Vol. VI 
The following are the results of examination of the rectified Boswellia 
turpentine oil as carried out by the Imperial Institute, London 
The oil on being examined at the Imperial Institute was found, 
to have the following constants :— 
Boswellia turpentine oil. Commercial turpentine oil. 
Sp. Gr. at 15°C. 08446 . 
Optical rotation aD +31° 24' 
Ester value, before acetylation 
Ester value, after acetylation 
American. French. 
0-858 to 0-877 0-865 to 0-875 
—9° 30'to 14° —29° to —33° 
17' (rarely 
slightly laevo 
rotatory). 
.. 
.36-4 
On fractional distillation, the Boswellia oil gave the following 
results :— 
Fraction boiling at— p or 
153° to 160°C. . . 89 
160° to 180°C..11 
The fraction boiling at 153°C to 160°C was redistilled, and 
practically the whole passed over at 155°C. 
“ For comparison with these figures it may be stated that 85 
per cent, of American turpentine oil usually distils between 
155° and 165°C.” 
Constants of the oil obtained on 
benzine in the Forest Research 
following constants :— 
Sp. Gr. at 23-21°C. . 
Flash point 
ND 23-5°C. 
aD . 
Fraction. 
Up to 155°C. . 
155°-160°C. 
160°-167°C. 
167°-170°C. . 
Residue above 170°C. 
large scale by the use of petroleum 
Institute Laboratory gave the? 
. 0-8427 
77° Fah. 
. 1-4575 
+ 21° 7*8' 
By volume. 
Per cent. 
52 
23 
15 
3-5 
6-5 - 
From these constants, it is evident that the oil, though refined by 
fractional steam distillation, still retains traces of petroleum benzine 
which affect its constants. The low flash-point is a disadvantage. 
(ii) Boswellia Rosin. 
The constants of Boswellia rosin were determined on two samples, 
which had been prepared in a model extractor, with either petroleum 
[ 321 ] 
