G4 THE SOILS AND CROPS OF THE FARM. 



in pieces about one foot long. Where stones are abun- 

 dant and it is desired to get rid of them, they may be 

 used, sometimes giving good satisfaction. Boards, 

 poles, brush; even straw may be worth using under 

 exceptional circumstances. "Mole drains," made by 

 drawing a conical shaped piece of iron or wood 

 through the soil at the desired depth, have done good 

 work for years in fairly retentive soils. In most parts 

 of this country, however, there is little reason for 

 using anything else than the ordinary drain tile, or 

 "pipes," as they are called in England. The use of 

 drainage tile was not common until about fifty years 

 ago, and comparatively few had been used in this 

 country until after the civil war. Within the last few 

 years there have been more than eight hundred facto- 

 ries for their manufacture at work in Illinois. For- 

 merly they were made in the shape of a horseshoe, at 

 first without, afterward with a "sole." Now round 

 tiles are almost universally used. It has been found 

 that good tile can be made from any clay suited for 

 brick -making. 



The most desirable qualities in drain tile are that 

 they shall be straight, smooth on the inside, with the 

 ends squarely cut off, free from cracks and fairly hard 

 burned. As the water enters the tile almost entirely 

 at the joints in any case, the porosity of the tile is 

 a matter of little importance . 



Hethod of Action of Tile Drains. — Lands are 

 wet because the water is held on or near the surface 

 of a soil so compact it cannot freely enter it; or be- 

 cause the soil is underlaid with rock, clay, hard-pan, 

 or other substance nearly impervious to water. The 

 land may be wet on hillsides because the impervious 



