Part I.] Puran Singh: Turpentine Oil and Indian Rosin. li 
a three-fold purpose, as an agitator, as a disintegrating agent and as 
a means of conveying the vapours of the spirits of turpentine to the 
condenser. 
The temperature of 120° C. is too low and the distillation pro¬ 
ceeds too slowly. While carrying out this process in the Labora¬ 
tory, the temperature had to be raised up to about 140° C. It may 
be noted here that if steam is passed without initially heating the 
crude resin, too much water comes over and very little oil of tur¬ 
pentine, so much so that commercially speaking this method of 
distillation is inadmissible. Besides, the yield of oil is extremely 
poor. 
Superheated steam distillation. —This is the most recent method 
that is in general use. The crude resin is kept in a steam jacket, 
fitted inside with a steam coil. The temperature of the chamber 
is made to rise to 150° C. by letting steam into the coil and the 
jacket at a pressure of 4 to T kilograms per sq. cm. At this 
temperature the volatile constituents of the resin come over. 
The vapours are led into a closed hollow cylinder, a sort of tubular 
condenser where mechanical arrangements are perfected so as to 
cause a partial vacuum during the process of distillation. This 
process, therefore, is a combination of vacuum distillation and 
steam distillation. It is said that oil of turpentine of a very good 
quality is obtained by this process. 
Another description of the superheated steam method is that 
the crude resin placed in a steam still is kept hot by means of a 
closed steam coil at 100° C., and when it reaches that temperature, 
superheated steam is let in. This process is said to be a very rapid 
one. 
Vacuum distillation. —While, in connection with the distillation 
of Finns longifolia resin, the writer of this Note was considering 
the adoption of the principle of vacuum distillation on a commercial 
scale in India, he was pleased to read the account of a patent, 
taken out in France, for distilling turpentine in vacuo. In this 
apparatus the crude turpentine is heated in vacuo and mechanically 
agitated at the same time. The apparatus used for the purpose 
has mechanical stirring arms and has its outlet connected with a 
reflux condenser, so that the heavier volatile substances fall back 
into the heating chamber, whilst the most volatile constituents 
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