34 TILE DRAINAGE 



If the "boss" ditcher has been careful not much extra 

 work will be required in getting the grade. It may be 

 gotten by stretching a tight line from the top of one stake 

 to the top of the next and measuring down from this at 

 intervals of 15 or 20 feet, or more easily and usually as 

 accurately by placing the eye as near the bottom of the 

 ditch as possible and sighting along, noting the places that 

 are too high and those that are too low. When the grade 

 is finished, take the grooving tool and slide it along to make 

 a little channel in which to lay the tile so that they will 

 remain in place. 



KIND OF TILE. 



A good drain tile should be hard-burned, giving a sharp 

 ring when struck. It was formerly thought that tile should 

 be soft and porous, so that the water could freely enter 

 them, but Mr. W. I. Chamberlain, in his "Tile Drainage," 

 page 75, cites some very interesting experiments which 

 seem to prove that the porosity of a tile has nothing to do 

 with the water entering it. There is plenty of space at 

 the joints for all the water to enter the tiles. Besides this, 

 a soft-burned tile is very susceptible to the effects of frost 

 and will soon begin to flake and crumble, as is illustrated 

 in Nos. 3 and 4 of Figure 8. It was found by crushing* 

 some hard and soft-burned tile that the former would 

 mthstand an average weight of 2,600 pounds, while the 

 latter would give way under an average weight of 1,100 

 pounds. Tile are sometimes made from clay containing 

 pebbles of limestone. These pebbles on burning are con- 

 verted into quick lime and as soon as water reaches them 

 will begin to slake and the chances are that the tile will 

 crumble. Tile, with lumps of limestone embedded in them, 

 are illustrated in Nos. 1 and 2 of Figure 8 and all these 

 should be discarded before laying. A good tile should be 

 smooth on the inside, straight and with the ends cut off 

 square. It should also be truly circular or hexagonal, de- 

 pending on which shape is used, so that the ends will fit 



