DRAINAGE 



283 



on the ends or perfectly straight, but when bowing in the 

 tile or irregular ends do not occur in the same piece laying 

 is seldom interfered with. Tile are sold by the thousand, 

 supposed to lay 1,000 feet of drain, the overrun in length 

 balancing the breakage and poor tile rejected at the trench. 



After University of Minnesota 



Fig. 231. Several sizes of tile 



Where they are subject to long shipments and hauls, they 

 will not always hold out, but a good quality of pipe carefully 

 handled will ordinarily lay the required number of feet. 



Water enters the tile through the joints and not through 

 the walls. Tile, unless very hard, will absorb a certain 

 percentage of water, but this does not indicate that the 

 water can percolate through the walls. The less water that 

 will pass into the walls of either concrete or clay tile, the 

 more lasting and durable will be the tile. Good tile should 

 generally not take over 10 to 12 per cent of its own weight 

 in water. There are some good clays that even when well 

 burned take a higher absorption and are still very durable. 



Hauling and distributing tile. For the smaller sizes of 

 tile a wagon with three boxes can be used, but for the larger 

 sizes or where the land is dry a strong hayrack is better. 

 The size of the rack or box necessary and the weight of the 



