Land Drainage and Soil Efficiency 



1825 



melting of the clay particles, which run together in a very dense mass 

 A low degree of porosity coincident with a moderate degree of vitrifica- 

 tion is especially desired 

 where the tile is likely to 

 freeze. In the soil the 

 pores in the tile become 

 filled with water, and if 

 it freezes in this condition 

 the walls of the tile may 

 be fractured and broken 

 up into scales. If even 

 one or two tiles in a long 

 line are thus destroyed, 

 the service of the drain is 

 jeopardized. Since vitri- 

 fied tile cost no more on 

 the average than soft tile, Fig. 47 

 there is no excuse for tak- 

 ing the risk in using the 

 soft tile. The drainage 

 efficiency of the tile is not 

 affected by the difference 

 in the porosity of the walls, 

 since the water enters at 

 the joints. 



Cement tile that are of 

 fairly good quality may 

 be made by hand or in 

 machines. It is doubtful 

 whether they can be made 

 as durable as the best clay tile. They should be carefully made of a rich 

 mixture. Sand that is a little loamy improves the quality, if the mixing 

 is thorough, as it reduces the amount of pore space. Whether cement 

 tile can be made at prices to compete with clay tile depends on the 

 size made and on the local situation in labor and materials for the two 

 kinds of tile. 



Only sound tile giving a true ring should be put in the ground. 

 The ends should be reasonably square and smooth, so that a good 

 joint can be made. This is most important when laying tile in 

 soil of a quicksand nature. Here special precautions against clogging 

 are necessary. 



The most common types of drainage tile and 

 other materials used for land drainage 



1. Cobblestones with smaller pieces of stone on top 



2. Flat stones placed face to face and parallel to line of 

 ditch 



3 and 4. Throated drains constructed of flat stones 

 used in different ways 



5. Pole drain 



6. Triangtdar box draitt 



7. Square box drain. Note construction for admis- 

 sion of water along lower edge 



8. Horseshoe tile laid on a board 



9. Horseshoe tile, bottom attached 

 Single sole tile with round opening 

 Double sole tile 

 Hexagonal tile 



13. Round tile 



14. Y-shaped junction piece 



15. Elbow piece 



10 

 1 1 

 12 



115 



