54 



The drain should be laid below the frost, and must be 

 below the reach of the sub-soil plow or trenching tools. 

 The fact that a large quantity of soil and fertilizing mat- 

 ter will be added to the present soil, which is rather 

 worthless in its character, will govern somewhat the 

 depth beneath the present surface. 



§htmtt Mta grains. 



There exists a positive relation between the depth of 

 drains and their distance apart — the tenacity of the soil 

 being the governing principle. The more retentive soils 

 require the drains to be nearer the surface and nearer 

 together, say from fifteen to thirty feet, while in porous 

 soils the drains should be deeper, and may be further 

 apart, say from twenty to sixty feet. The thorough 

 working or trenching of the ground will obviate the 

 necessity of placing the drains as near to each other as 

 would be required to remove immediately the water 

 now present in the soil. When this, which now occupies 

 the ground so universally, is removed, that which falls 

 afterward would find in the soil, rendered porous by 

 being worked, a ready outlet through these drains, 

 although they would have less immediate effect upon 

 the ground. 



The leading principles which have been enumerated, 

 have been followed out in the construction of the plan 

 of drainage. It is not deemed essential to enter into the 

 details of digging the trenches. If not done by con- 

 tract, the lines of drains should be laid out, and the 

 gangs so divided that each man shall work with certain 

 tools — one with a spade for the top soil, another with a 



