156 THE SEED OF OWALA OR OPOCHALA. 



history in that city, and it is only recently that I have, by the assistance 

 of Sir Wm. Hooker, been enabled to examine them in the Botanical 

 Gardens at Kew. I succeeded in seeing there the entire fruit, which is 

 a pod of about 1 foot in length by If to 3 inches wide. Its general 

 shape resembles that of a large haricot, its surface is brown and wrinkled. 

 The two valves open easily, and display four or five seeds separated from 

 each other by the same number of compartments. Of these seeds those 

 near the ends of the pod are smaller and more angular in shape than 

 those in the centre, which are oval. The length of this seed is nearly 

 double its breadth, its weight varies from i- of an oz. to | of an oz., and its 

 density is greater than that of water. It consists of two principal parts, 

 a husk and a kernel. The husk very much resembles that of the large 

 chesnut in colour and brilliancy, but it is thicker and its structure more 

 compact and less elastic. Its surface too is unequal, presenting sinuosi- 

 ties or raised fibres, which extending from the sharp end of the seed? 

 where it is attached to the pod, reunite themselves towards the opposite 

 extremity. The husk is strongly attached to the kernel, though it 

 can be peeled clean off without fracture, and the imprint of the 

 fibres can then be seen on the perisperma or exterior husk. The 

 kernel is of a greenish white colour, which becomes darker by 

 exposure to the air ; it consists of two cotyledons closely united to 

 each other. 



Many experiments have shown me that the mean between the weight 

 of the husk, and the total weight of the seed, is from 1 to 6, for instance, 



Husk 16-66 



Kernel 83-34 



The quantity of water in the whole seed is 5 1 per cent., and of ash 

 2 T \ per cent. The husk contains 5^, and the kernel 2 £ per cent, of 

 ashes, but the ash of the former contains more silica than that of the 

 latter. The oil of the kernel, although considerable in quantity is ob- 

 tained with difficulty by pressure. In an experiment with ether, I 

 obtained from the kernels alone, 62 per cent, of oil, and 57*47 per cent, 

 from the seed and husks. When the oil had undergone repeated wash- 

 ings in distilled water, and the superfluous moisture had been drained 

 off, its proportion was reduced to 56 per cent, in the case of the almonds, 

 and 50-11 per cent, in that of the whole seed, 



This oil known as owala in the Gaboon, and opochala in Fer- 

 nando Po is of a clear yellow colour, but becomes brown when it has 

 been purified. At a temperature of 11 deg. it gradually becomes less 

 limpid, at some degrees lower it becomes turbid, and at zero changes 

 into a viscous mass. Its density is very nearly the same as that of olive 

 oil. If this oil be spread in thin layers over the surfaces of different 

 substances, and left for several days exposed to the air it still preserves 

 its original fluid state. This property the oil of owala possesses in com- 



