300 IRRIGATION. [Cuar. XVI 
operations, because there will then be a continuance 
of frequent and copious showers, which will moisten 
the earth and the air until such time as the 
young rootlets have laid hold of the.soil and are 
capable of sending up sufficient nourishment to the 
stems. 
During the growth of the rice, the fields are 
always kept flooded when water can be obtained. 
The terraces near the base of the hills are supplied 
by the mountain streams, and the fields which are 
above the level of any adjoining river or canal are 
Water-wheel for Irrigation. 
flooded by the-celebrated water-wheel, which is in 
use all over the country. These machines are of 
three kinds. The principle in all of them is the 
same, the only difference being in the mode of 
applying the moving power; one is worked. by the 
hand, another by the feet, and the third by an 
