On Draining. 
2G9 
may be produced, and without the aid of manure, for many 
years. 
But the whole of this land is much too wet — it is too salt — and 
its powers will not be appreciable until after deep and complete 
under-draining. It appears, however, that the lands warped at a 
greater distance from the mouth of the river, must be skilfully 
treated in respect of under-drainage. A complete power of deep 
under-drainage should be established to withdraw the water and 
keep it down low beneath the surface when injurious, whilst there 
should be provided means of sustaining water nearer to the surface 
and to the roots of plants, when under the influence of such a dry 
season as was experienced in 1844. 
In many of these warped lands means exist to fulfil this end, as 
water is raised out of the ditches by machinery when in excess, and 
the height of water in the ditches is maintainable by drawing it from 
the high land drains. A farmer, residing near to Hatfield Chase, 
informed me that he considered he saved crops of the value of 1500/. 
in 1844 (when it will be remembered we had fourteen weeks of 
hot sun, without a drop of rain), by his command of water to charge 
his ditches. The warped lands are very commonly divided into 
fields of 10 acres, being squares of 220 yards, surrounded by open 
ditches, and it is considered that the water is thoroughly drawn out 
of the soil to the level maintained in the ditches ; but this I much 
doubt, and am satisfied from my observation of these flat warped 
lands, both in wet and dry weather, that they would be astonishingly 
benefited by a system combining both sub-drainage and sub-irri- 
gation ; but it is possible that the farmer may have reason for not 
draining this soil more deeply or more completely, unless means 
are provided for sub-irrigation in droughty seasons. 
There has been rather recently introduced by some drainers a 
practice of making what they term air-drains, with the view of pro- 
viding for a ventilation of the soil, and also for promoting, as they 
think, a freer flow of water from drains. As regards the latter 
point, it is quite certain that such air-drains must be superfluous 
and unnecessary. The fact of water entering subterranean drains 
at all is quite decisive as to the universal presence of air in soil, 
and no one has shown or has attempted to show, so far as I know, 
its insufficiency. Water could no more issue from a drain laid in 
the earth, than it could flow from a light barrel, if air did not press 
on the surface of the liquid within it. Every one knows how small 
a vent-hole at the top of a cask suffices to enable us to withdraw a 
great stream from it at the bottom, and every one knows that the 
bulk of liquid discharged in a given time is in quantity precisely 
equal to, the volume of air which enters in the same time. The 
fact of rain-water sinking through the soil is demonstrative of the 
permeability of that soil to air, as every drop of water which 
