THE PALMS OF EUROPE AND AFRICA. C7 



cesses all remaining discoloration is expungeLi, 

 and on parting -with its lieat, and again becoming 

 solid, it has a pvri'e Avhite colour, as free from 

 stain as the driven snow. The next step is to 

 spread it out in thin layers on the surface of 

 mats made of cocoa fibre, Avhieh, after receiving 

 their coating of oil, are piled one upon another 

 into high stacks, an iron plate being interposed 

 between every pair of mats to counteract the 

 elasticity of the fibre. The pile of oiled mats 

 is then placed beneath a powerful hydraulic 

 press, by which an immense pressure can be 

 applied, equivalent to a weight of many hun- 

 dreds, perhaps thousands of tons. It will be 

 necessary here to explain that most fixed oils 

 are composed of two substances or principles, 

 called by chemists stearin, and elain, or olein, 

 which may be separated by mechanical means. 

 The former of these is usually solid, and the latter 

 liquid at the ordinary temperature of the air. 

 Now palm oil contains both these principles, 

 and by means of the hydraulic press they are 

 separated, the stearin remaining between the 

 cocoa mats, while the olein, as the pressure 

 increases, trickles down the sides of the pile, 

 and is received in vessels placed beneath for 

 that purpose. . But the utmost power of the 

 hydraulic press is insuflficient at ordinary tern- 



