On Draiiiiiir/. 
415 
xhdllow open (Iraui.t or fvrrovs, tniadoiix clay aoi/x mil lie vet, hvt 
vith deep open drains tliei/ ivill lie dry ; in. ilie oneinstanee the water 
passes over the surface of the land to the drain, in the other 
through the fssnres, ivorm-bures, Sfc. to the drain, lohich clearly 
demonstrates the advantage of deep drains, and that the teater 
should percolate through the fissures, Sfc. of the subsoil to the 
drain, instead of over the surface, as is the case tcith shallow 
drains. I have in the winter season observed fields of grass and 
arable land, with shallow open drains or furrows, that if there 
were a deep ditch on any one side of the field, in which the water 
did not flow within 3 feet of the surface, the land for 4 or 5 yards 
from the ditch would be very dry compared with the lands in the 
middle of the field ; but if the generally conceived opinion is 
correct, the whole field would be in the same state of dryness, 
whether the drains which carry off the water are 3 feet or only 6 
inches below the level of the land, provided the water does not 
lie upon it. 
If the injurious effects of water passing over the surface to the 
drains are admitted, and it must be by all who have paid attention 
to the subject, to thoroughly drain clay land, this evil must be 
avoided. I propose, from the experience and observations I have 
made on land drained by myself and others, to state the mode 
by which so desirable an object can be obtained under general 
circumstances, on tenacious clay-land, comparatively level or 
slightly undulating. 
Fig. 1. 
.\ I'lan of I'iuallel UiainiuL' 
B 
j 
a 
(i 
1 
a. 
a. 
a- 
a, 
a. 
a 
a. 
a. 
a. 
\a 
V 
'<£ 
tt. 
. cr 
'.tt 
1 
e. 
\ 
1 
\ 
\ 
i 
i 
'\ 
I 
I 
i 
i 
■R- 
1 
I.enstli of thp Fielil 13 Chains. 
VOL. IV. 
