IRRIGATION 



79 



rand have been brought under cultivation and utilized in 

 growing lettuce, celery and other crops. The tile serve 

 both for irrigation and for drainage. An impervious bed 

 of hardpan lies from 2 to 4 feet below the surface and the 

 sandy or loamy top soil is about 18 inches deep. The 4- 

 inch water mains are made of sewer tile, cemented at the 

 joints, the 3-inch laterals of drain tile are 20 to 25 feet apart 

 and 12 to 15 inches below the surface. Sawdust, cinders 



FIG, 15. DRILLING MACHINE FOR THE INSTALLATION OF THE 

 SKINNER SYSTEM OF IRRIGATION 



or moss are placed over the joints ! fo prevent filling with 

 sand. A fall of at least I inch in 100 feet of tile is pro- 

 vided for drainage. The laterals run into open ditches 

 dug for drainage purposes. Subirrigation is an Meal 

 system for conditions as they exist at Sanforc. 



122. The overhead system of irrigation promises to 

 revolutionize garden irrigation in the East. Numerous 



