24 
Indian Forest. Records . 
[Vol. VI 
determined in a Engler’s viscosometer :— 
— 
Moisture, 
'fete, per 
cent. 
Ash, 
per cent. 
Strength of so¬ 
lution. 
Time taken for 
the outflow of 
200 cc. at 25°C. 
(1) Boswellia gum . 
18-75 
3-28 
20 grams to 250 
cc. 
h. m. s. 
0 1 21 
(2) Gum arabic 
13-53 
3-29 
20 grams to 250 
cc. 
0 1 17 
(3) Gum tragacanth 
19-91 
2-87 
10 grams to 10001 
cc. 
1 13 18 
(4) Distilled water . 
I 
*• 
- I 
0 0 52 
Boswellia gum dissolved in 12-5 parts of water and filtered through 
clotli gave reactions similar to gum arabic, only the emulsion was slightly 
more opaque. The solution of soluble Boswellia gum as dissolved in 
5 parts of water is more jelly-like than a similar solution of gum arabic. 
Fart IV. Isolation of the three constituents of the gum-oleo- 
resin of Boswellia serrata. 
The problem of separating the three products from each other has 
been the subject of prolonged enquiry, first on a laboratory scale and 
lately on a semi-commercial scale, the object of the latter being to pre¬ 
pare samples for valuation and at the same time to obtain first-hand 
evidence as to the most suitable type of plant. 
The observations made in this chapter are based on actual experi¬ 
ments and record the difficulties actually met with. 
1. Preliminary remarks. 
From the nature of the three products, it is evident that the process 
of separating the products, from each other must necessarily be a mixed 
one, namely solvent-extraction and steam distillation. The separation 
of the gum from the oleo-resin is done by a solvent and the separation 
of the turpentine from the rosin by steam. 
Steam distillation might answer the purpose if only oil and a residual 
mixture of the gum and resin were the products aimed at, or a solvent 
alone might suffice were the oleo-resin and the gum products required. 
From an industrial point of view, however, it is essential that all three 
products should be recovered in a high grade of purity. By steam 
distillation, it was found that the residue consisted of resin and gum in 
[ 326 ] 
