TILE DRAINAGE. 27 



flat tin root' from which all the water must run as fast as it 

 falls. But the tiled land, especially if covered with a mat of 

 clover or whe-it, is like a flat roof covered with a deep layer 

 of tine sponge, which will absorb quite a shower before it 

 will let any run off, and will retain much water, slowly 

 parting with it for hours after the rain ceases. 



In early autumn, however, when all the surface depres- 

 sions are empty on even untiled clayey land, after a long 

 dry summer, we can see that the untiled land would store 

 more water than the tiled before parting with it. But that 

 is the time when disastrous floods do not occur, at any rate. 

 Tile drainage, therefore, after the soil is saturated in fall 

 will, as a rule, diminish the suddenness and violence of 

 floods below, just in proportion to the area tile-drained. 

 That is, tile drainage will (and does) furnish a sort of res- 

 ervoir or storage-layer of porous soil for holding heavy rains 

 back for a time from the water-courses below, thus extend- 

 ing the time and therefore diminishing the violence of the 

 delivery below. Such has been my careful observation of 

 actual facts on and below my own land, and such seems to 

 me to be the rational scientific explanation. And yet I 

 know it is a popular belief that tile drainage increases floods. 

 Open ditches and the clearing of forests do ; but tile drain- 

 age, I think, does not as a rule. 



Twelfth. Drainage, both open and with tiles, improves the 

 health of a mji.on. For best results, large regions must be 

 drained ; but even on a single farm it diminishes malarial, 

 diphtheritic, and typhoid tendencies to drain a considerable 

 area around the house and barns by a thorough system of 

 tile drainage. The farmer may not be able to control or 

 greatly influence the general drainage of the township or 

 county in which he lives ; but he can control that of the 

 farm on which and the cellar over which he and his family 

 live. In' the tenacious and almost impervious clayey soils 

 that are found over so large a portion of Northern Ohio, I 

 believe the cellar should have a good four-inch tile drain 



