Systems of Drains 



457 



In Pig. 145 are represented diagrammatically two 

 ways of laying out a system of drains for the same 

 piece of land. The area drained is about 14 acres, 

 and with lines of tile laid 100 feet apart, system 

 A requires 625 feet of 4 -inch and 3,020 of 3 -inch 

 tiles, while that of B makes necessary only 550 feet 



Fig. 145. Two systems of laying out drains. 



of 4 -inch and 2,830 feet of 3 -inch tiles to drain 

 equally well the same area. 



Where long lines of tile must be laid in which 

 more than one size will be required, three systems 

 have been adopted, that represented in A, Fig. 145, 

 already described ; a second, A, Fig. 146, and a third, 

 B, in the same figure. In the case of A, Fig. 146, 

 covering a section 2,000 feet by 900 feet above the 





