FORMATION OF BEDS. 43 



in fig. 7, in which three secondary ridges, a, a, a, with 

 the head-ridge, A, B, and the canals, c, c, c, belonging to 

 each are shown, with an open drain, d, d, d. The arrows 

 show the direction in which the water flows. Fig. 8 

 shows the profile of the ridge and section of the head- 

 ridge with its canal of supply as if they were cut down 



Fig. 8. PROFILE OF BED. 



through the center, A, heing the head-ridge with its canal, 

 a, a, the bed or secondary ridge, c, the drain at the foot of 

 the bed, and the dotted line shows the course the tile 

 drain would take below the surface, should one be laid. 

 Where the ground has a slope in either direction the 

 system to be adopted will be much simpler than the pre- 

 ceding one. At the head of the slope will be placed the 

 canal of supply. This will be the only permanent work 

 undertaken. The method of cultivation of the field or 

 garden will control the method of distributing the water. 

 It will be necessary, however, to cultivate the ground in 

 drills or hills or subordinate beds, upon which the water 



Fig. 9. FURROWS FOR A REGULAR SLOPE. 



may be turned when it is needed, leading it by small fur- 

 rows or canals made with the hoe or a small hand plow 

 in whatever direction, down or across the slope, as may 

 be desired. Generally the arrangement of the canals of 

 supply will be as shown in fig. 9, in which the supply 

 canal is seen at , and the drain which carries off the 

 surplus water is seen at the foot of the slope at ~b. A 

 low ridge separates the latter from the next supply canal. 

 In this method of irrigation the water may be supplied as 



