io8 



ENGINEERING FOR LAND DRAINAGE. 



grade. The curves should be long, so that by turning 

 the tile in their beds close joints will be made. If an 

 open joint is necessary on the outer side of the curve, 



TJjj. 



Fig, 26. — Method of Using Tile-hook. 



Tile-hook. 



a bat can be laid over it and clay tamped against it in 

 such a way that it will be secure. All cracks that are 

 larger than J inch should be covered with bats. Fol- 

 lowing this method the drain is finished and secured as 

 the work proceeds from the outlet up grade. When 

 the point for joining a branch is reached, the proper 

 tile with Y branch should be placed in position and 

 the opening covered securely to await the construc- 

 tion of the branch line. 



When large tiles are used — p-inch and larger — it 

 will be necessary for the workman to walk in the bot- 

 tom as he grades, which work must be done with the 

 shovel. The same care should be used in securing the 

 proper grade as above noted. Tile should be laid from 

 the outlet up, the workman standing in the bottom and 

 placing them with his hands. They should be secured 



