WINTER IBEIGATION. 101 



where frosts are neither severe nor long continued that 

 Winter irrigation is admissible. Where light frosts alter- 

 nate with sunny days, a covering of a few inches of water, 

 gently flowing across the meadows, protects as well as 

 fertilizes the grass. At this season the copious rains or 

 melting snows carry into the streams an immense amount 

 of fine, earthy matter, which may be arrested and caused 

 to be deposited in a thin sheet upon the soil. In the 

 course of several years this deposit has been known to 

 raise the surface of the meadow many inches, every inch 

 of this increase consisting of matter of the greatest fer- 

 tilizing value. Where Winter irrigations can be made, 

 they will be found of the greatest value, for they prepare 

 the crop which is to be cut in the Summer by supplying 

 in a great measure the necessary subsistence for its growth. 

 Where the level of the field or the supply of water is 

 such as to permit it, a constant current may be kept 

 flowing over the surface during the period when growth 

 is suspended, or from November or December until Febru- 

 ary or March. 



Where it is necessary to make a series of levels to be 

 irrigated in succession, each may in its turn be overflowed 

 for a week ; or by arrangement of ditches and banks, the 

 water from the upper level may pass over each lower one, 

 supplying the whole, if it is in sufficient quantity. But 

 where the supply of water is only limited, it is preferable 

 to irrigate each level successively, for the reason that by 

 far the largest quantity of suspended matter will be de- 

 posited by the first of the waters made to flow from one 

 level to another, and in this case, the lower ones will receive 

 a diminished quantity of deposit, in proportion to their 

 distance from the source of supply. When the tempera- 

 ture falls sufficiently for ice to form, the quantity of wa- 

 ter should be increased so as to keep a current constantly 

 flowing beneath the ice. If the cold is sufficient to con- 

 geal the whole supply of water, so that ice rests upon the 



