30 
Indian Forest Records. 
rVoL. VI 
For want of superheated steam and the suitable plant, the 
latter process was not tried on a large scale, though 
the experiments conducted in the laboratory were a 
distinct success. 
(Hi) Preparation of the products for the market. 
(a) Turpentine. 
From the volatile nature of the oil, rectification in any form is not 
advocated, and this opinion is confirmed both by the Imperial Institute 
and by the Manager of the Shalimar Paint and Colour Works Company 
Limited, Calcutta. The flash point of the oil is already so low that any 
steps to lower it further, which would be the case if it is redistilled, 
are inadvisable. 
(b) Rosin. 
The points to be guarded against when dealing with the rosin are, 
overheating, which not only results in deepening an original good ruby- 
red colour, but also reduces its “ strength,” while every care must be 
taken to free it from fine particles of dirt, by allowing a sufficient period 
for settling in the tanks, while it is still in the form of solution in the 
solvent. *It may be noted here, that in the case of Boswellia rosin, if 
this step of settling is omitted or not carefully carried out, it seems 
impossible to clean the rosin of this dust at any other stage of working. 
(c) Gum. 
From the nature of the process, the major portion of the impurities 
is found in the residual gum, only the fine dust having been carried 
away by the solvent. From repeated experiments, it was found that 
it is almost impossible to refine the gum on a large scale by dissolving 
it out in water or alkali and recover it in its original purity by evapora¬ 
tion in open copper vessels. It will be found advisable to put it on the 
market, in the same form as other similar gums, namely as flour. To 
reduce it to this state involves grinding and sieving through a fine series 
of sieves which hold up the fine particles of bark but allow the flour 
to pass through the mesh. 
(d) Under-extracted gum. 
By under-extracting the material, a gum containing 25 per cent. 
—30 per cent, of rosin was obtained on a large scale in the Forest Research 
Institute Distillery. From preliminary experiments, which were fur¬ 
ther confirmed by Mr. W. Raitt, Cellulose Expert, it was ascertained 
that this substance could be used as a subsidiary sizing material. If 
this, on further trial, proves to be correct it would be quite easy to cut 
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