Note 258 — CHAP. XVIII. Of Ploughs.

A swerdy Furrow cut off by only one Coulter, being whole, is apt to stand up on its Edge, or lie hollow; and then, being open to the Air, it does not rot; but when it is cut by several Coulters, it has not Strength to support itself, it falls down, lies close to the Earth under it, and, excluding the free Air from the Turf, it soon becomes rotten. And for killing the Turf of swerdy Land is the chief Use of the Four-coultered Plough: For doing of which there is this Advantage, that as in a whole Furrow there are often Strings of Couch-grass, Three or Four Feet long; but, when cut by this Plough, there is scarce a String left of one Foot long: And these Strings being apt to send out Roots from every Knot or Joint, the shorter they are cut, the more they will be exposed to the Air and Sun, which will kill them the sooner.