Part VI.] Preparation of Turpentine , Rosin and Gum. 23 
ether or Boswellia turpentine as solvents. The results are as follows *. - 
— 
Sample pro¬ 
duced with 
Boswellia 
turpentine. 
Sample pro¬ 
duced with 
petroleum 
ether. 
Sp. Gr. at .. 
1-058 
Acid value (cold). 
42-51 
43-71 
Saponification value. 
88-40 
89-66 
Iodine value (Hubl. 18 hours) . 
98-20 
97-10 
A bulk sample of Boswellia rosin prepared with petroleum benzine 
as a solvent, was sent to the Imperial Institute, London, for commercial 
valuation and determination of its constants with the following 
results :— 
Moisture 
Ash . 
Melting point 
Acid value . 
Saponification value 
Per cent. 
0-7 
0-03 
6s°c. 
55-1 
90-2 
(Hi) Gum. 
A sample of gum, completely freed from resin and insoluble woody 
matter was analysed and gave the following results : 
9 
Per cent. 
Moisture, etc. 
18-75 
Ash 
3-28 
Water solubles in 5 parts of water 
74-20 
Water solubles ( i.e ., the portion dissolved in 60 parts 
of water by repeated extraction) 
74-35 
Bassorin ..•••••• 
7-05 
Bassorin when using 60 parts of water . 
6-90 
In order to form a fairly thick jelly, two parts of water have to be 
added to the gum, while by adding five parts of water a thin solution 
is obtained, and it is not until 50 parts of water are added that approxi¬ 
mately complete filtration is possible. 
The following are results of tests for comparative viscosity of the 
water solubles of Boswellia gum, gum arabic and gum tragacanth as 
[ 325 ] 
