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ploughing, by which the land is left in as light a state as 
if it had been dug or trenched. It is very singular that 
the subsoil plough, invented by Smith of Deanston, and 
which has effected such a change in wetlands in Scotland, 
has scarcely been even heard of by the farmers of this 
district, and yet this is the very land to which it is adapted. 
Before using the subsoil plough the land must be well 
drained to the depth of 22 inches at least ; the width from 
drain to drain may vary from 4 to 7 yards, according to 
the nature of the subsoil. The subsoil plough follows the 
common plough after it has turned up each slice, and by 
the double ploughing the land is to be stirred to the depth 
of 16 inches, 6 inches being left between the sole of the 
plough and the top of the drain. Concerning this plough 
and thorough draining, I shall beg leave to quote two 
passages from Mr. Smith's pamphlet, published by 
Drummond of Sterling : — " Thorough draining is the 
^'foundation of all good husbandry, and when combined 
" with deep ploughing ensures a general and uniform 
" fertility, assisted, no doubt, by thdse essentials 
" thorough working and cleansing, ample manuring, 
" and a proper rotation of cropping. Being asked by 
" the Committee of the House of Commons — ' Have you 
" used your subsoil plough without having the land first 
" drained V he answered, ' I have, and it is the worst 
" thing possible to deep plough land without having it 
" first drained' ; and it is upon that ground that in 
"England the shallow ploughing is so much resorted 
" to ; the deeper stiff clay is ploughed the worse it is, 
" because there is thereby a greater reservoir formed to 
" hold water. So soon as wet lands are thoroughly 
" drained, deep ploughing may follow with the greatest 
" advantage, but not sooner." The following passage 
is taken from Mr. Shaw Lefevre's Letter to his 
