10 
Indian Forest Records. 
[Vol. IV. 
Indian turpentine oil from Pinus longifolia. —Most of the 
Indian oil has up to date been obtained from Pinus longifolia. 
The chemical composition of this oil has been the subject of 
investigation at the Imperial Institute, London, (vide Chapter 
II and Appendix D). Like Russian turpentine oil, it consists of 
pinene and sylvestrene. According to the experiments conducted 
at the Forest Research Institute, Dehra Dun, the proportion of 
high-boiling terpenes increases or decreases as the oil is distilled at 
a high or low temperature. The oil distilled at a low temperature 
contains a greater amount of low boiling terpenes and consequently 
is of better quality than that in which the low boiling terpenes are 
polymerised into higher terpenes by excessive heat. 
The specific gravity of the redistilled oil obtained by distilling 
at high temperature is between 0*963 and 0‘864 at 22° C. On frac¬ 
tional distillation in an ordinary fractional distillation flask, 80 
per cent, of this oil passes below 165° C. The sample of oil 
redistilled twice gave the following fractions : — 
155°—163° C.55 per cent. 
163°—165° C.37-5 „ 
165°—172° C.12-5 „ 
(ii) Methods of Turpentine Distillation. 
There are various methods of distilling turpentine oil both from 
the resinous wood and from the oleo-resins. A brief description of 
some of the processes for distilling the oleo-resins is given below. 
Furnace heat process. —This consists in gradually raising the 
temperature of crude resin to 150° C. and even higher by the direct 
heat from the furnace. It is more like a dry distillation process. 
Towards the close of the operation water is poured into the still 
when brisk effervescence takes place and the remaining oil is some¬ 
what rapidly distilled. This is a very primitive method. It has 
been mostly given up in favour of mixed distillation and steam 
distillation processes. 
Mixed method of distillation. —In this process the crude resin 
placed in a sort of steam still set up on a furnace is heated to about 
120° C. when steam is admitted. In this process, steam serves 
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