148 LAND DRAINAGE 



diameter than the main tile, the bottom of the lateral 

 ditch must be planned to approach the bottom of the 

 main ditch at a height of one-half the difference between 

 the outside diameter of the main and of the lateral tile. 

 To make connection, a hole should be picked in the wall 

 of the main at the proper point (see Fig. 59), and made 

 of sufficient size and shape to permit the entrance of the 



FIG. 60. Five-inch tile shown in Fig. 59, with the opening enlarged to 

 receive 3-inch tile. The 3-inch tile is shown with end shaped to 

 set in the opening in the larger tile. In this particular case the 

 opening and trimming are done for a 90-degree connection. A 60- 

 degree connection would require a larger opening and more trimming 

 of the 3-inch tile. 



lateral tile at the proper angle. The end of the lateral 

 should be rounded back and shaped so that the end, 

 when the tile is in place, shall stand flush with the inner 

 wall of the main. (See Figs. 60 and 61.) When the 

 lateral thus fitted is set into place, fragments of broken 

 tile should be carefully laid in over the joint and earth 

 packed about it. This is to prevent the working in of 

 soil material. 



198. Top connection. By the second method, the 

 lateral discharges its water down through the top of the 



