On Draining. 
259 
Woodford, July 4, 1846. 
Dear Sir, — On the arable land, which we have drained to the depth 
of 4 feet, I have not found it necessary to maintain any open water- 
furrows. I am not at all an advocate for water-cuts, or surface- drains 
of any description on arable land, it being my belief that when they are 
used for the purpose of carrying ofiF the water after heavy rains, they are 
also the means of washing away a quantity of fine soil, which might 
otherwise be retained on the land. I believe that if even the most re- 
tentive of soils were drained to a considerable depth, and rendered friable 
by the aid of Read's pulveriser, there would not then be any use of open 
water -furrows on that description of land. In reply to your other question 
I have to say, that adjoining one of the fields, which was drained to the 
depth of 4 feet, is a field of the same subsoil (a strong blue clay), which 
was only three years ago drained in the old fashioned way of " shallow 
draining," I have frequently observed that after heavy rains the water 
beg^an to run first from the deep drains, and that when the shallow drains 
did run, they did not appear to me to discharge the same quantity of 
water to the same quantity of land as the deep drains. 
I was quite against draining land so very deep until I saw the great 
advantages derived from it. 
Yours, &c. 
Andrew Thompson. 
The last remark made Mr. Thonipson, as to the deep drains 
giving issue to rain water, in land under precisely similar circum- 
stances, before shallow drains, agrees with the observation of a 
great number of farmers^ whose land has been so drained ; and it 
would be difficult to cite a more apposite proof, I think, of the 
superior condition into which the mass of the soil is brought by 
deep drainage. That this should occur in a field where shallow 
drains exist in the neighbourhood of deeper drains, and within 
their influence, would be naturally expected, as the water keeps 
on descending below the level of the higher and until it reaches 
the level of the lower vents, where it meets with free water, and 
then begins to travel horizontally to the drain. The reason, how- 
ever, why the deeper drain in one field should begin to discharge 
before another and a shallower drain in another field, or in a very 
distant part of the same field, having precisely similar soil, is not 
quite so obvious. I have this day received from a tenant farmer 
in Yorkshire an account of an observation of his, that a 4 feet 
drain began to run five minutes earlier after rain than another 
drain 16 inches deep at a distance, but in the same field. Some 
experiments are being made which may elucidate this action, 
which tells so favourably for the deeper drainage.* 
* See the Report of the Evidence given before the Select Committee 
of the House of Lords last year, for information on this head. Mr. liobert 
Neilson's statement of the result of intermingling deep and shallow drains 
in the same field is highly instructive and to the purpose. 
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