17 
Paet I.] Puean Singh : Turpentine Oil and Indian Rosin. 
temperature than the boiling points of the terpenes that constitute 
the oil of turpentine. This is so, because the temperature of 
distillation of turpentine oil with steam, (both vapours being 
saturated), is less than 100° C. This fact was confirmed by an 
observation of the temperature of distillation carried out at Bhowali. 
Though the distillation temperature is low, the temperature at 
which the crude resin is kept at the bottom of the still ranges 
throughout between 165° C. and 175° C. At the end of the opera¬ 
tion, at the same place, when the still was allowed to cool down a 
little, and the colophony taken out in an open pan, the temperature 
of the colophony was noticed to be 175°—180° C. It is thus possible 
that in water distillation colophony undergoes some decomposition 
towards the later stages of distillation. This supposition was 
confirmed by observing from time to time the fumes from the 
charge hole, which at certain stages were found to be distinctly 
yellow in colour, no doubt due to the decomposition of colophony 
inside the still. It is thus evident that in the present process 
unless the temperature inside the still is carefully regulated, there 
is great danger of the resulting turpentine oil becoming more or 
less vitiated by the decomposition products of colophony. 
In the steam distillation, on the other hand, no great care is 
needed for the regulation of the temperature, which can easily be 
controlled, and the decomposition of colophony avoided with greater 
certainty than in water distillation. In the steam distillation 
process, large quantities of resin can be handled in a compara¬ 
tively shorter time, and the rosin obtained is of a lighter colour and 
better quality. 
Thus the process of steam distillation has some advantages 
over the present process, such as rapidity, facilities in handling 
large quantities of resin by employing a battery of steam-stills 
worked by one or two boilers, both for distillation and rectification 
of the oil, saving in labour and fuel, etc. At the present stage of 
the turpentine industry in India, the immediate supersession of 
the latter method by the former may possibly meet with objection, as 
it has been found practicable to improve the quality of turpentine 
from Chir resin produced b}^ the present method by redistillation 
and other means. In addition to this, the adoption of the steam 
distillation process combined with vacuum distillation and redis¬ 
tillation plant would mean the setting up of distilleries on an entirely 
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c 
