458 



Irrigation and Drainage 



3 3' 3" 



line a a, there would be required 9,000 feet of 3-inch 

 tiles and 9,000 feet of 4 -inch tiles, with lines laid 

 100 feet apart ; but following the second system, B, 



it would only be neces- 

 sary to lay 3,000 feet of 

 4- inch tiles, with 15,300 

 feet of 3 -inch. At 1 

 cent per foot for 3 -inch 

 and 1.6 cents for 4 -inch 

 tile, the difference be- 

 tween the purchase price 

 of the two sets of tile 

 would be $33 in favor 

 of the system B. The 

 saving grows out of the 

 fact that one line of 4- 

 inch tile has 'ample ca- 

 pacity to drain not only 



Fig. 146. Two systems of laying out drains. the gtrip Q f ground [ fc 



traverses, but at the same time to discharge the water 

 gathered by the three lines of 3 -inch tile emptying 

 into it from the upper half of the field. 



It will be observed that in both diagrams the nine 

 lines of tile have been brought to one outlet in the 

 stream, rather than to make them all separate, as 

 might be done in A, or to make three outlets, as could 

 readily have been done in the case of B. To have 

 finished the system with three outlets would not have 

 been a bad or expensive plan, but to have as many 

 outlets as there are lines of tile is not generally to 

 be recommended. 



