On the Drainage of Land. 
323 
little manure is applied. There is another very essential benefit 
derived from draining grass-land, which is this, that in very grassy 
seasons, whicii are generally wet, the land will not become 
poached so soon, therefore the cattle can remain out to consume 
it later in the year, without so much waste of food or injury to the 
land, which will also be made sound for sheep, though these are 
not the stock for grass-land generally ; still there are times when 
they can be kept on it to advantage, if it be dry and sound. 
Having tried to make it appear plain what land requires draining, 
I will now endeavour to state how it should be done by answering 
the questions proposed by the Society. 
The Depth and Frequency of Drains. — The one must be 
partly ruled by the other ; if you cut the drains deep, they are not 
required so frequent ; if they are put near together, they need not 
be so deep. This rule will hold good to a certain extent on all 
descriptions of soil, but from the great variety which exists in the 
retentiveness and porousness of soils, you cannot reduce the depth 
and distance to one fixed rule. Land that lies in ridges (or lands 
as the term is here) is generally drained in the furrows, and though 
the ridges are of very various widths, if they have a considerable 
slope up their sides, say from 1 in 10 to 1 in 20, the drains along 
the furrows will be sufficient to keep the ground dry, if put in at 
a depth of 24 or 30 inches, the latter being preferable ; but on 
some retentive clay-soils, where the slope is 1 in 40 or less, and 
the lands more than 12 or 14 yards wide, it will require them 
deeper, or else more frequent. Land lying in ridges is generally 
drained at the least expense ; from its lying in a round form, part 
of the land is in a measure drained, and by putting the drains in 
the furrows, you keep a piece of land dry, perhaps 16 yards wide, 
whereas if the same description of soil were level, it might want 
draining at 6 or 8 yards' distance. I have heard of land lying in 
ridges being drained at equal distances, paying no regard to the 
ridge or furrow ; but this plan must be wrong, even if you go 
deep enough to drain it, Irom its costing a great deal more in 
cutting through the ridges. Now the chief point in laying out 
drams is to know how far your land will draw from the drain. 
The following is a rough sketch of the power of drawing in four 
different subsoils, with drains a chain apart, 30 inches deep on 
level land :■ — - 
No. 1, a very porous subsoil. No. 2, rubble mixed with clay. 
A 
Drain. Drain. 
No. 3, clay with veins of grit or sand. No. 4, tenacious clay. 
A B ABC 
Drain. 
Drain. 
