OP AGRICULTURE. 31 



blind or covered drams. The open drains consist of 

 one or more channels or ditches running through the 

 lowest part of the field. A natural channel or 

 branch often serves the purpose. The land can be 

 either bedded so as to run into these main ditches, 

 or, if necessary, cross ditches cut, emptying into the 

 main drains.. These cross drains should have as 

 much " fall " as possible on level land near their 

 mouths. The covered drains are in every respect pre- 

 ferable to the .open drains. They are constructed by 

 digging ditches from three to four feet deep, parallel 

 to one another, and leading into a larger or main 

 channel, like the open drains. But instead of being 

 left open, a tube or pipe is formed of tiles, broken 

 stones, timber or coarse brush is laid in the bottom 

 to carry off the water, and the ditch then filled up. 

 There are several points to be observed in the con- 

 struction of covered drains. If the land is level or 

 nearly so, the main channel should run along the 

 lowest part of the land to be drained, and should 

 have as much "fall" as possible toward the outlet 

 from the field. The side drains should run at right 

 angles (or as nearly so) to this, and with as much 

 "fall" as can be given them. If the land to be 

 drained is a hill side, the main drain should run along 

 the base of the hill, but have sufficient fall to carry 

 off the water freely. The smaller drains should run 

 directly down the slope into the main drain. 



The distance apart that the side drains should be 

 placed depends upon the character of the subsoiL 

 In * stiff clay it would be best to place them from 

 twenty -five to thirty feet apart. But in a gravel ly, 

 platy soil, they may be often separated by a space of 



