I 12 



benefit to all, 



Underdraining may be classified as follows : 



1. Thorough drainage. 



2. Partial drainage. 



3. Sufficient drainage. 



The first as the word implies, affects equally every part of the 

 land, — has no open ditches and but one " outlet." It usually 

 requires the ser\dces of an engineer, and is a very nice and 

 somewhat expensive piece of work, — as for instance a large field 

 of clay land, whether lying low or not, and without regard to its 

 condition as to wetness from springs, may be more profitably 

 treated by thorough drainage than by any other system. The 

 rule usually prescribed for this kind of drainage is, tile laid not 

 more than thirty-three feet apart and as nearly three feet deep 

 as the nature of the ground and the drop of the outlet will ad- 

 mit. Its cost at prices of labor since the war is not far from 

 i^ioo per acre. 



2. "Partial Drainage" is such as only partly or imperfectly 

 secures the object aimed at, although it often docs much good, 

 as when one drain is placed through the middle of a piece of 

 land, leaving parts on either side that may be full of springs — or 

 where no sufficient fall can be had to secure a proper outlet. 

 This kind is to be tolerated only when the exigences of the case 

 permit of nothing better. 



3. "Sufficient Drainage," may be described as that which com- 

 pletely secures the object without any unnecessary expense. For 

 example — a field of sandy loam, upon a subsoil of gravel, would 

 ordinarily be considered as sufficiently drained by nature, and 

 yet it may be kept too wet by a spring of water in its higher part. 

 To tap this spring and draw its water in the most direct line 

 to the nearest available outlet would be sufficient. Sufficient 

 drainage is the kind which Mr. Gregory has applied with admir- 

 able judgment and complete success. 



