50 IRRIGATION. 



dition to be disturbed with the hoe. This trough is 

 peculiarly adapted for use in the system of bedding before 

 described, as it may be laid upon the crest of the head 

 ridge, and the cross channels connected with the furrows 

 upon the crests of the beds. These latter may be made 

 of common open horse-shoe drain tiles inverted. The uses 



Fig. 19. TROUGH FOB CBOSS-FURBOW3. 



to which this kind of drain tiles may be put in surface 

 irrigation are very numerous, but they will be so obvious 

 to those interested that it is necessary only to suggest 

 their usefulness in this regard. 



For carrying the water beneath roads or paths a wooden 

 pipe should be provided, (fig. 20). This is made of stout 

 plank, placed longitudinally for the sides and cross-wise 



Fig. 20. CULVERT FOB BOADS. 



for the top and bottom. This method of construction 

 gives the extreme strength of the material where it is 

 most wanted, and prevents the crushing of the culvert 

 by the weight of a loaded cart or wagon, the wheels of 



