1: 0644 verization, by means of agricultural implements, have but [mall effe&t in reducing it. For although the clayey par ticles be ever ſo well reduced by the air, by froſt, or by agris cultural operations in the field, yet, when expoſed to heavy rains, or 2 ſufhcient quantity of water to bring them into union, the maſs becomes as hard and ſtubborn as ever. Theſe foils can only be effe&ually reQified by an intermixture of ſubſtances permanently incoherent, or as nearly ſoas poſſible: and a quantity muſt be applied, and ſo mixed as will be ſuf- ſcient to break the general coheſion of the maſs, and to form as it were innumerable[mall canals or drains to carry off the ſuperabundant moiſture, and allow the roots of plants to ra« mify at pleaſure. Strata and patches of ſtiff clay are to be found in this county, and they exhibit all the marks of having originally been formed by water at reſt, or nearly ſo, by which it was enabled to depoſit the argillaceous particles that were ſuſpended in it. The mountains and high lands in this, and in moſt other diſtri&s in Scotland, contain an inexhauſtible ſource of clayey particles, for the increaſe or the reparation of the inferior or lower lying ſoils, that may have been waſted by water carrying them down the rivers,&c. into the ſea, The decompoſible whinſtone, of which many of the rocks are compoſed, and almoſt all the ſchiſtus that abound(ſo plenti- fully in this country, are, by the action of the weather, re« duced to cläy, which 13 no ſmall part of their compoſition. "This clay, by its eaſy miſcibility with water, is carried off by ſtreams, however ſmall, and by them is lodged in the lower grounds; to replace that part of the ſoil that may have been waſhed away by heavy rains and floods.

The lighter ſoils, which are abundant in this county, are ſuch as contain ſand, and decayed vegetable and animal ſub. Rances, by which the ſtiff coherency of the clay is broken, and the ſoil, by the admixture of theſe matters, is rendered more open and porous, and becomes ſpecifically lighter than a clay