OIL. 



187 



3ent. of its weight. It is used in fattening cattle and as manure 

 Oil, when newly expressed, is always turbid and very mucilaginous ; 

 it becomes clear by standing ; but it always retains certain sub- 

 stances which lessen its quality, particularly when it is intended 

 for burning in lamps. 



Greater obstacles are encountered in extracting the oil from some 

 of the pulpy fruits than from seeds. In extracting olive-oil, the 

 olives are crushed under millstones ; and the paste which results be- 

 ing put into flat baskets of wicker-work, is subjected to the press. 

 The first pressing yields virgin oil, which is used for the table. 

 Having removed the baskets from the press, their contents are mix- 

 ed with a little boiling water, replaced, and pressed again, by which 

 a new quantity of oil is obtained. But the pulp is not yet exhausted ; 

 by special treatment it still yields a quantity of oil of inferior quality, 

 which is employed in the manufacture of soap. 



The fruit of the palm yields the oil which it contains with great 

 readiness. I have extracted a butter of excellent quality and very 

 agreeable taste by simply boiling the nuts or berries of the Palma 

 real in water. The cocoa-nut yields two qualities of oil, according 

 to the mode of extraction. To prepare the best kind, the flesby 

 part of the fruit is grated, and the pulp being pressed, a milky fluid 

 is obtained, which yields the oil by boiling. An inferior quality of 

 oil is obtained by causing the cocoa-nuts to putrefy ; when the putre- 

 faction has advanced to a certain stage, the oily pulp is thrown into 

 copper vessels and exposed to the sun, and the oil which then rises 

 to the surface is skimmed off. This oil is brown, and has a strong 

 smell ; it contains fatty acids which have probably been set at lib- 

 erty by the putrid fermentation. 



The value of the produce in oleaginous seeds of a given extent 

 of land, and the quantity of oil which these seeds will yield, depend, 

 as may readily he conceived, on a variety of causes which it is not al- 

 ways easy to appreciate with precision ; such as climate, the nature 

 of the soil, the system of husbandry followed, &c. The observations 

 of M. Gaujac of Dagny on the various plants usually cultivated for 

 the sake of their oleaginous seeds, will however suflice to give a 

 notion of their comparative productiveness in oil and cake : 



Crop. 



WINTER CROPS. 



Colewort 



Rocket 



Rape 



Swedish turnip.. 

 Curled colewort. . 

 Turnip cabbage.. 



SPRING CROPS. 



Gold of Pleasure 



Sunflower 



Flax 



White poppy .... 



Hemp 



Summer rape 



Seed produced 



per acre in 



Cwts. qrs. lbs. 



13* 



