274 On Irrigation. 



2. The Methods of conducting the Process. 



Water meadows are of two sorts ; flowing^ calculated for 

 a flat country ; and catch-work^ for sloping grounds. 



Flowing Meadows. Where the ground is flat," the soil 

 is formed into beds, or broad ridges, like those met with at 

 bleachfields. They are commonly from 30 to 40 feet wide, 

 and nine or ten poles in length ; as, in such situations, the 

 great object is, to be able to carry off the water quickly, 

 when once brought on. Hence it is necessary to throw up 

 the land into high ridges, with drains between them. More 

 of the failures in irrigation arise, from the ridges not being 

 sufficiently high, and the slopes not being sufficiently steep, 

 than from any other cause ( 4I1 ). 



Catch-work Meadows. It is difficult to give an intelligible 

 written description of the mode of making these meadows. 

 To be properly -understood, the operation must be seen. It 

 may, however, in general be remarked, that the system is 

 calculated for sloping grounds ; and that, after the water is 

 brought from the original stream into a new cut, it is stop- 

 ped at the end, on as high a level as the case admits of, by 

 which the water is made to fill the trench, and run over at 

 the side, so as to flood the land below it. But as the water 

 would soon cease to run equally, and would wash the land 

 out in gutters, it has been found necessary, to cut small pa- 

 rallel trenches, at the distance of from 20 to 30 feet, to catch 

 the water again (whence the name originated), and the same 

 plan of spreading, or diffusing, is continued, until the water 

 reaches the main drain at the bottom of the meadow ( 4ia ). 

 A great advantage attending the catch-work system is, that 

 it is not only less expensive, but the same quantity of water 

 will do much more work. 



In either of these ways, irrigation promotes the growth 

 of grass. The herbage of dry land is impoverished from 

 the want of water ; that of wet land, by its remaining stag- 

 nant ; but both these evils are remedied by the processes 

 above described. 



3. Circumstances to be considered, previous to the Plan being 

 undertaken. 



The first point to be ascertained is, whether there be a 

 sufficient quantity of water at command. For want of due 

 attention to this important circumstance, mistakes have some- 



