94 HANDY-BOOK OF HUSBANDRY. 



level would be attained only after a considerable time. Toward 

 the end of the flow the water would stand highest at the points 

 farthest distant from the outlet. So, in the land, after a drenching 

 rain, the water is first removed to the full depth, near the line of 

 the drain, and that midway between two drains settles much more 

 slowly, meeting more resistance from below, and for a long time, 

 will remain some inches higher than the floor of the drain. The 

 usual condition of the soil (except in very dry weather) would be 

 somewhat as represented in the accompanying cut (Fig. 28.) 



Fig. 28. 



^f^?" 





-i.'.ti-^i DRAINS 



The dark shading to the line b represents the water of satura- 

 tion in the soil, which, immediately after a rain has stood at <?, 

 and is descending toward c. In time of drought it would in 

 most soils, descend nearly or quite to the level of the drains, or 

 even, in severe drought, much lower than this. 



To provide for this deviation of the line of saturation, in 

 practice, drains are placed deeper than would be necessary if the 

 water sank at once to the level of the drain floor, the depth of 

 the drains being increased with the increasing distance between 

 them. 



Theoretically, every drop of water which falls on a field 

 should sink straight down to the level of the drains, and force a 

 drop of water below that level to rise into the drain and flow 

 off. How exactly this is true in nature cannot be known, and is 

 not material. Drains made in pursuance of this theory will be 

 eflFective for any actual condition. 



Any system, which so disposes of the water falling on the land, 

 produces the following important results : — 



