Laying Out Drains. 



3' 3' 3" 



3" 3* 3 



3 ' 3' 3" 



3' 3" 3* 



FIG. 124. Two systems for laying out drains. 



In Fig. 124 drains are laid out by two systems for the 

 same area of 14 acres with the lines 100 feet apart. By 

 the system A 625 feet of 4 inch main and 3,020 feet of 3 

 inch laterals are required ; while by the system B only 550 

 feet of 4 inch and 2,830 feet of 3 inch tile are required to 

 cover the ground so as to 

 secure equal drainage. It 

 will be seen that in the sys- 

 tem A the ends of all the 

 laterals traverse 50 feet of 

 territory drained by the 

 main. 



When long lines of tile 

 must be laid, requiring 

 more than one size, three 

 systems have been used : 

 1st, that represented at A, 

 Fig. 124; 2d, that at A, 

 1 25 and 3rd, that at B, 125. 

 In the second case, cover- 

 ing an area 2,000 feet by 

 900 feet, above the line a a, 

 9,000 feet of 4 inch and 



FIG. 125. Two systems for laying out 

 drains. 



