164 



AGRICULTURE. 



NUMBER or ACRES AVHICH A TILE OF A GIVEN 

 DIAMETER AND PER CENT GRADE WILL 

 DRAIN WHEN USED AS AN OUTLET. (Elliott.) 



Table 1. — Discharge of Tile from 4 to 20 inches in 

 Diameter on a Grade of 1 foot per 100 feet. 



Table 2. — Grades per 100 feet, and their Square Roots. 



To determine the number of acres that a tile main of 

 given size and grade will drain, multiply the discharge of 

 the tiles, according to size (see Table i), by the square root 

 of the grade upon which it is proposed to lay the main 

 (Table 2). When it is desired that the main shall carry i 

 inch in depth per acre in twenty-four hours, multiply this 

 result by 24 ; if one-half inch, multiply by 48 ; if one-fourth 

 inch, multiply by 96. (Farmers' Bulletin, No. 40.) 



