IX DRAINAGE 69 



to make the land absolutely dry, but to prevent the stagna- 

 tion of water in it that is, to make the rain water pass 

 slowly through the soil, allowing it to leave in its passage 

 sufficient moisture to keep the soil moderately damp below 

 the surface. In light, porous soils, drainage operations must 

 not be carried so far as in heavy, clay ones ; indeed the poro- 

 sity of the soil and its capability of holding moisture, will 

 always indicate to an intelligent person acquainted with the 

 principles of agriculture, what amount of drainage is neces- 

 sary for his lands. 



