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XXXI. — On the 2'>ropcr Materials for fiUiiif/ itp D)-ains, and the 
Mode in which U'atcr enters them. By RouiiUT Bkart, 
Alviiougii I felt incompetent to give the extensive information 
required by the conditions for the Prize Essay on Draining, I 
wish to lay before the Council of the Society the result of my 
experience and observation in draining from 300 to 400 acres of 
cold clay land. In the first instance, without any practical know- 
ledge, I commenced draining with the plough, wood, wood and 
straw, peat, block and turf or wedge draining, and at shallow 
<lepths with tiles ; but the greater part of the land drained witli 
the plough, wood, »Scc., is now re-drained with tiles. In the tile- 
draining, the depth at which the tiles are laid varies considerably, 
in some fields 12 to 15 inches, in others 15 to 20, again, 20 to 
oO, and in one instance, on a piece of very flat table-land (very 
difficult to drain), from 30 to 40 inches below the furrow; but if 
I lie land were laid level, the depth of the drains would generally 
be G inches deeper than stated. 
I hope to show that the drainage of tenacious clay-soils is not 
as in the draining of gravel, peat, or other light soils, a mere 
practical operation, but must be considered in relation with the 
operation of under-drains by the aid of the atmosphere contract- 
ing the subsoil, and thereby increasing the size of the fissures, for 
the water to percolate to the di'ains, and also with the injurious 
effect arising from water lying in the land below the level of the 
drains (where these are shallow), rising by capillary attraction, ex- 
])anding the subsoil, and partially closing the fissures, and thus 
checking the free infiltration oH the water ; so that attention to the 
operation of these agents, the infiltration of water, and the level- 
ling of high-ridged lands, is of the greatest importance. 
Having thus briefly introduced the subject, I shall proceed to 
illustrate it as follows : — 
1st. The geological character of the clay soils of Huntingdon- 
shire. 
2nd. Depth and frequency of drains, &c. 
3rd. Fall required, and the necessity of levelling high-ridged 
lands. 
4th. Materials in this district best for draining. 
5th. FiUing-in, whether with tenacious or porous earth. 
Gth. The practical mode of draining clay land, lying wet 
from surface water, in which is considered the laying out the 
ground for the mains and small drains, with the cost of draining 
with tiles, wood, peat, turf or wedge, and block draining. 
1st. The (jeolof/ical character of the claij-soils of Hiintinf/don- 
shire. The clay soils extend over the greater p.art of the county, 
running from East to West, lying between the oolitic hills and 
