These parting Furrows, and their Ridges, must be made more or less oblique, according to the Form and Declivity of the Hill; but the more horizontal they are, the sooner the Rain-water will run off the Lands; for in that Case it will run to the Furrows, and reach them at right Angles, which it will not do when the Ridges (or Lands) are oblique; and therefore the Water’s Course cross the Lands will be longer[218]. Every one of these horizontal Trenches receives all the Water from the Rills, or little Gutters, wherein the Water runs betwixt the Mould and the Clay; these are all cut off by the Trenches, which receive the Water at their upper Sides, and carry it away, as the Trunks of Lead plac’d under the Eaves of a House do carry away the Rain-water. [218] The natural Course of Water being downwards, it would always run by the nearest Way to the Bottom of the Hill, if nothing stopt it; but the Water runs from an Hill in Two Manners; _viz._ Upon the Surface of the Staple, and upon the Surface of the Clay that is under the Staple; that which runs under keeps its strait Course from the Top to the Bottom of an Hill, under a Ridge that is made exactly with the Descent of the Hill, except that Part of the Water that rises up into the Mould, and a very little that soaks into the Furrows, for when the Furrows are not made exactly with the Descent, the more oblique they are to the Descent, the longer will be the Water’s Course under the Ridges; and the shorter, as they are nearer being at Right Angles to the Descent. ’Tis also the same with the Water that falls upon the Surface of the Ridges; for the more horizontal they are, the shorter its Course will be from them to the Furrows, which carry it off; and the less of the Water will sink into the Ridges, the less oblique and the nearer to Right Angles to the Descent they are made.