454 WEST AFRICAN FORESTS AND FORESTRY 
of oil, the exploitation of it is almost impossible; owing to the diffi- 
culties in removing the husk, the external sugary pulp, and then the 
thick fibrous shell under the pulp. At the Imperial Institute,1 Betu 
oil on analysis showed : 
Specific gravity .. i 0-919 
Acid value .. oe Ss st 5-0 
Saponification value ws .- 196°7 
Todine value bet oe 2 = 92°5 
Hehner value as a -. 92°5 
Reichert-Meissl value .. 24 — 
Unsaponifiable matter .. ais 0°6 
Titer test .. a a ..  34°6°C. (approx.) 
The oil is a mixture; the results of analysis are as follows: 
Per cent. 
Olein ay te oe .. 3d 
Linolein.. is .. 33 
Stearin and palmitin a .. 34 
The family of Simarubezx also contains the trees Irvingia Bartert 
and I. Smithii. These yield the Dika nut, or, as it is sometimes called, 
Gaboon chocolate. The sun-dried kernels keep in a perfectly good 
condition for some time. According to the investigation of the Imperial 
Institute | the kernel contains about 43-5 of “ Dika fat.” It would 
be useful either for soap or for candle making, and be worth from £25 
to £27 per ton, and the Dika kernels are valued at from £10 to £12 per 
ton. Locally, however, they are often worth as much as this, but no 
doubt increased production would mean a reduction in price. So far 
the tree has only been planted in isolated instances, and otherwise is 
a forest tree which has been protected by the native for the value 
of its fruit. The decortication usually takes place near the tree, or 
in an open place where the nuts are split in half with a sharp matchet, 
which releases the kernel in the centre, and though often cut in half 
by this method, it apparently does not mean a large loss of oil to the 
kernel. According to the analysis of the Imperial Institute 1 the kernel 
showed : 
cs a 
Yield of fat (on kernels) per cent. ti 54°3 60-1 66°3 
Specific gravity at ah al C. _ 0-863 —_ 
Acid value s 6-6 12°6 1°8 
Saponification value .. +e 6 ac 244°5 250-0 243-8 
Iodine value .. nen ae es 5:2 3°3 4:2 
Unsaponifiable matter ne ce 0-7 —_— = 
Titer test ies i a a oa 34°8° C. — easy 
‘Melting-point of fat .. a os Ss _— = 39°2°C 
{ 
1 Colonial Report, 88, Oil Seeds, Fats and Waxes, Imperial Institute, 1914, 
