CROPS 



135 



bushels. The seed is used for feeding poultry, and as a source 

 of oil which is sometimes used to adulterate linseed oil. 



Average Composition of Hemp- seed and of Hemp -seed 

 Cake. 



In hot countries the hairs on the stems and leaves secrete a 

 resinous substance, which has powerful narcotic qualities. In 

 colder climates this secretion does not occur. 



Rape^ or Cole {Brasaica najms and Brassica campesiris). — 

 A plant belonging to the turnip family, grown either as a 

 fodder crop or for seed. The seed is valued for the oil (about 

 42 per cent.) which it contains. The oil, either expressed or, 

 more generally, extracted by volatile solvents, is sold as rape 

 oil or colza oil. The plant resembles the turnip plant, except 

 that it has not a fleshy "root" and bears yellow flowers. 

 Several varieties are known, some being sown in the autumn 

 and harvested in the middle of the next summer, others sown 

 in the spring and reaped in the autuDjn. The residue after 

 extraction of the oil from the seeds is chiefly used for manurial 

 purposes, as it is not readily eaten by cattle. The plant 

 resembles in composition and manurial requirements the 

 turnip or swede. 



Castor-seed {Ricinus communis). — The castor-oil plant, some- 

 times called " Palma christi," U well known as an ornamental 

 plant in England. In many warm countries it is almost a 

 weed. In temperate climates it is only an annual, but in 



