Those Vegetables commonly sown in our Fields, require a middle Degree of both, not being able to live on the Sides of perpendicular Walls in hot Countries, nor under Water in cold ones, neither are they amphibious, but must have a Surface of Earth not cover’d, nor much soak’d with Water, which deprives them of their necessary Degree of Heat, and causes them to languish. The Symptoms of their Disease are a pale or yellow Colour in their Leaves, and a Cessation of Growth, and Death ensues as sure as from a Dropsy.
The only Remedy to prevent this Disease in Plants is, to lay such wet Land up into Ridges, that the Water may run off into the Furrows, and be convey’d by Ditches or Drains into some River.
The more a Soil is fill’d with Water, the less Heat it will have.
The Two Sorts of Land most liable to be overglutted with Water, are Hills, whereof the Upper Stratum (or Staple) is Mould lying upon a Second Stratum of Clay;
And generally all strong deep Land.
Hills are made wet and spewy by the Rain-water which falls thereon, and soaks into them as into other Land; but being stopp’d by the Clay lying next the Surface or Staple, cannot enter the Clay; and for want of Entrance, spreads itself upon it; and as Water naturally tends downwards, it is by the incumbent Mould partly stopp’d in its Descent from the upper towards the lower Side of an Hill; and being follow’d and press’d on by more Water from above, is forced to rise up into the Mould lying upon it, which it fills as a Cistern does a Fountain (or Jet d’Eau). The Land of such an Hill is not the less wet or spewy for being laid up in Ridges, if they be made from the higher to the lower Part of the Field; for the Force of the Water’s Weight continued will raise it so, as to cause it to issue out at the very Tops of those Ridges; the Earth becomes a sort of Pap or Batter, and being like a Quagmire, in going over it, the Feet of Men and Cattle sink in till they come to the Clay.
There are two Methods of draining such a wet Hill: The one is to dig many Trenches, cross the Hill horizontally[217], and either fill them up with Stones loose or archwise, through which the Water, when it soaks into the Trenches, may run off at one or both Ends of them into some Ditch, which is lower, and carries it away; then they cover the Trenches with Mould, and plow over them as in dry level Ground.
[217]For if they are made with the Descent, and not across it, then they will be parallel to the Rills of Water, that run upon the Surface of the Clay under the Staple (or upper Stratum of Mould), and would be no more effectual for draining the Hill, than the digging of one River parallel to another, without joining it in any Part, would be effectual for draining the other River of its Water.
This Method has been found effectual for a time, but not of long Continuance; for the Trenches are apt to be stopp’d up, and then the Springs break out again as before: Besides, this is a very chargeable Work, and in many Places the Expence of it may almost equal the Purchase of the Land.
Therefore ’tis a better Method to plow the Ridges cross the Hill almost horizontally, that their parting Furrows, lying open, may each serve as a Drain to the Ridge next below it; for when the Plough has made the Bottom of these horizontal Furrows a few Inches deeper than the Surface of the Clay, the Water will run to their Ends very securely, without rising into the Mould, provided no Part of the Furrows be lower than their Ends.