32 
Indian Forest Records. 
[Vol. VI 
On fractional distillation the Boswellia gave the following results :_ 
Fraction boiling at p er cen ^ 
153° to 16d°C. ... 89 
160° to 180°C. . n 
The fraction boiling at 153° to 160°C. was re-distilled, 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 163°C. and 85 to 90 per cent, of 
French oil between 155° and 165°C. 
It was found that the Boswellia turpentine oil readily dissolved resins such as 
colophony, dammar, sandarac and soft copal, but that varnishes prepared in this 
way dried more rapidly than those made with commercial turpentine oil and gave 
a less lustrous surface. 
Commercial Value. 
In order to obtain technical opinions as to the probable value of this Boswellia 
turpentine oil, samples were submitted to several turpentine merchants and dis¬ 
tillers and varnish manufacturers likely to be interested in the product. The 
general opinion expressed was (1) that the oil is of a very good quality and closely 
resembles American turpentine oil, except as regards the smell, which is regarded 
as peculiar though not unpleasant, and (2) that the Boswellia oil could be success¬ 
fully employed like ordinary turpentine oil in the manufacture of varnishes. 
All the firms consulted thought that the Boswellia oil would be readily saleable 
in the United Kingdom. One firm stated that its commercial value should be 
approximately equal to that of American turpentine oil, though the difference in 
smell alluded to might constitute a slight drawback. Another firm considered 
that the oil would find a ready market in the United Kingdom if it could be sold at 
about 25 per cent, under the price of American turpentine oil, and a third firm valued 
it at about 30s. per cwt., with American turpentine oil at 37 s. per cwt. 
Remarks. 
The rapid drying of this Boswellia turpentine oil, is possibly due to the remova 
by distillation in India of the higher boiling fractions. It was found at the Imperial 
Institute that a mixture of 10 parts of Boswellia turpentine oil and 1 part of the 
higher-boiling residual Boswellia “ essence ” which had been thus removed in India, 
gave a somewhat better result in varnish-making than the turpentine oil alone. 
This view is further borne out by the fact that when the higher-boiling fractions 
were removed from commercial turpentine oil tire resulting distillate yielded a quick¬ 
drying and somewhat inferior varnish to that obtained with the original oil. 
It thus seems probable that a product even more closely resembling commercial 
turpentine oil could be produced by modifying the distillation of Boswellia tur¬ 
pentine oil so as to include a portion of the higher fraction, and that this oil would 
be more suitable for use in varnish manufacture than the oil represented by the 
present sample As a guide to wha 't is required it may be suggested that the Bos- 
ivellia oil should be made to conform as far as possible to American turpentine oil 
in range of boiling point. 
One of the firms of varnish manufactures consulted by the Imperial Institute 
pointed out the difficulty of expressing a definite opinion regarding the value of 
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