OIL. 139 



cattle, the loss is perhaps less to be regretted, inasmuch as the oily 

 matter evidently assists in the fattening ; but wben the cake is used 

 as manure, the oil which it contains is almost entirely lost. 



It is often of importance to the agriculturist to ascertain precisely 

 the quantity of fatty principles contained in oleaginous seeds. For 

 this purpose, it is enough to bruise a given quantity of the seed and 

 to digest it in successive portions of sulphuric ether. After a first 

 digestion, the seed is bruised or pul-verized anew, and the bruising 

 is now accomplished without difficulty. The process may be con- 

 cluded by boiling with a mixture of equal parts of ether and alcohol. 

 The ethereal solutions are decanted from the seed into a porcelain 

 dish, the weight of which is known. The ether evaporates sponta- 

 neously and the oil remains, the weight of which is then taken. 



The following sums may be taken as a pretty accurate estimate 

 of the average quantity of oil yielded by the different oleaginous 

 seeds : cole wort, winter rape, and other species of cruciferous plants, 

 from 30 to 36 and 40 per cent. ; sunflower about 15 per cent. ; lin- 

 seed from 11 to 22 ; poppy from 34 to 63; hempseed from 14 to 

 26 ; olives from 9 to 11 ; walnuts 40 to 70 ; brazil nuts 60 ; castor- 

 oil beans 62 ; sweet almonds 40 to 54 ; bitter almonds 28 to 46 ; 

 madia sativa 26 to 28 per cent. 



The quantity of oil yielded by any seed subjected to the press is 

 always considerably less than that which it contains, and the oil re- 

 tained in the cake appears to be in larger proportion as the starch, 

 the woody tissue, and the albuminous matters are more abundant. 

 Thus maize, or Indian corn, which contains from 8 to 10 per cent, 

 of fluid oil, gives mere traces of its presence under the press. 



The oily and fleshy fruits, such as those of the olive and the palm, 

 yield a considerable quantity of oil. In the southern countries of 

 Europe, particularly those which are so well protected that their 

 olive-trees escaped the severe winter of 1789, as many as about 

 816 J lbs. of oil per acre are obtained, with proper care. The trees 

 which were killed during this memorable winter sprouted again 

 from the roots, and at the present day yield from about one quarter 

 to one half the above quantity, accocding to the spaces left between 

 them, which vary considerably. Under similar circumstances in 

 regard to climate, it will readily be understood, that the quantity of 

 produce will be influenced by the quantity of manure put into the 

 ground. In some countries the olive is never manured, save indi- 

 rectly ; that is to say, the ground between the trees is only manured 

 with a view to another crop, which is grown between them ; in other 

 countries, again, in the neighborhood of Marseilles, for instance, it 

 is the practice to manure the olive plantations, directly, every three 

 or fonr years. 



The olive enjoys remarkable longevity ; I have mentioned one 

 more than seven centuries old, and the term of the tree's existence 

 appears only to be limited by the severe winters which cause it to 

 die, from time to time. The produce must of course depend upon 

 the age of the trees which compose a plantation. Up to eleven 

 y^ars, M. Gasparin shows that an olive-tree still remains all but un- 



