GRADING THE DITCHES FOR TILE. II3 



The rodman should observe the joints and whether im- 

 proper tile have been used. If the line * * passes * ' the 

 tile are ready to be blinded and the ditch filled. If a 

 line has been constructed skilfully J inch per station 

 should cover its variation from a true grade. The 

 judgment of the inspecting engineer should be some- 

 what carefully exercised in deciding whether certain 

 faults that may be found will effect the efficiency of 

 the work. He must, however, have nerve enough 

 to correct faulty construction and insist upon its being 

 made right. This is only justice to the employer and 

 works no hardship upon the contractor, if what was 

 expected of him was fairly set forth in the contract. 



Heavy Rains on Unfinished Drains. — During the 

 construction of a drainage system the work is often 

 hindered in the spring of the year by heavy rains which 

 fill to a greater or less extent the trenches which have 

 been dug and submerge the lines of tile which have 

 been laid. In the case of mains with light fall, there 

 is considerable risk from dirt and silt which may be 

 washed into the drain and partially obstruct it. The 

 tile drain may be securely closed at the upper end, but 

 if the water is permitted to flow over the top of the 

 tile, the drain itself being nearly empty, the weight of 

 the water passing down through the joints until the 

 drain is full carries with it a large quantity of earth 

 which by reason of the lack of current may not pass 

 on through the drain. The better way is to permit the 

 water to enter direct through the end of the drain and 

 fill the tile completely, letting the surplus pass on over 

 the top of the drain. The drain being full and the 

 water flowing under a good head will prevent the top 



