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,^ Betu 

 oil on analysis showed : 



Specific gravity .. .. .. 0-919 



The oil is a mixture ; the results of analysis are as follows : 



Per cent. 



Olein 33 



Linolein . . , . . . . . 33 



Stearin and palmitin . . . , 34 



The family of Simarubese also contains the trees Irvingia Barteri 

 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 ^ the kernel 

 showed : 



1 Colonial Report, 88, Oil Seeds, Fats and Waxes, Imperial Institute, 1914. 



