140 LAND DRAINAGE 



best to throw all the soil to one side of the ditch. Some- 

 times the top soil is thrown upon one side and the lower 

 soil upon the other. 



After any cut, if for any reason a considerable quantity 

 of loose soil lies in the ditch, it should be removed with a 

 long-handled shovel before the next cut is begun, or, if 

 the last cut has been made, before starting to use the tile 

 scoop. (See Fig. 55.) 



182. Finishing the ditch. Before beginning the last 

 cut with the ditching spade, the boning line should be 

 tightly stretched over the top of the bars and just over 

 the straight edge of the ditch, and the rod brought 

 into use to guard against digging the ditch too deep 

 at any point. If in stretching the line, the ends are 

 tied to the end grade bars, braces should be placed in 

 front of the stakes; otherwise the bars and their 

 stakes will be drawn out of place, and the line will be 

 both sagged and lowered. A better way is to drive a 

 stake into the ground beyond the end bars, wrap the 

 line once around each end grade bar, and then tie to 

 the stake just driven. 



When the ditch has been dug to within two inches of 

 the bottom, as above described, the line above the bars 

 should be carefully moved out over the center of the ditch, 

 and again sufficiently tightened to remove all sagging. 

 From time to time the line should be examined and, if 

 sagging is resulting from the stretching of the line, it 

 should be retightened. With the tile scoop and rod, a 

 trough or hollow is dug along the center of the ditch and 

 finished so that at all points it shall measure just 5.5 feet 

 below the line. This requires careful work and frequent 

 use of the boning rod bearing the 5.5-foot mark, pre- 

 viously mentioned. (See Fig. 56.) 



