98 



AGRICULTURAL ENGINEERING 



scraper or other form of handled scraper. A team is hitched 

 to the scraper by a chain so as to pull directly across the 

 ditch. The scraper is placed behind the waste bank, and the 

 team stepping ahead pulls a scraper load of earth into the 

 ditch. The team is then backed and the scraper pulled back 

 by hand. The latter operation furnishes the greatest objec- 

 tion to this system, for it is very heavy work. 



Outlet Protection. All tile outlets should be protected 

 in such a manner that the earth will not be washed away 



from the end tile 

 and cause them to 

 be displaced. The 

 cheapest form of 

 outlet is made by 

 preparing a wooden 

 box into which the 

 last few lengths of 

 tile may be placed. 

 This is not a very 

 satisfactory form of 

 protection. The bet- 

 ter plan is to build a 



Fig. 63. A good outlet protection for a tile bulkhead of maSOnry 

 drain. It is desirable, however, that grating 



or bars be placed across the outlet to keep out and an apron Upon 

 small animals. . 



which the water 

 may spill without washing away the soil. The latter 

 may not be needed, or a few stones will generally suffice. 

 Concrete makes a splendid bulkhead. A six- to ten-inch 

 wall where only two or four feet of earth is to be held 

 back will be found sufficient. This wall should extend well 

 below the tile to prevent undermining. The last few tile 

 should be glazed sewer tile, as they will resist freezing and 

 thawing better than common drain tile. Iron rods or netting 



