The Reason why Land is enrich’d by lying long unplow’d, is that so very few Vegetables are carried off it, very little being produc’d; the Exhaustion is less than what is added by the Atmosphere, Cattle, _&c._ But when ’tis plow’d, a vastly greater Quantity of Vegetables is produc’d, and carried off, more than by the old Husbandry is return’d to it. But strong Land, being naturally less porous, is made for a Time lighter (as well as richer) by a good Division; the Separation of its Parts makes it more porous, and causes it to take up more Room than it does in its natural State; and then it partakes of all the Benefits of lighter Land. When strong Land is plow’d, and not sufficiently, so that the Parts remain gross, ’tis said to be rough, and it has not the Benefit of Tillage; because most of the artificial Pores (or Interstices) are too large; and then it partakes of the Inconveniences of the hollow Land untill’d. For when the light Land is plow’d but once, that is not sufficient to diminish its natural Hollowness (or Pores;) and, for Want of more Tillage, the Parts into which ’tis divided by that once (or perhaps twice) Plowing, remain too large; and consequently the artificial Pores are large also, and, in that respect, are like the ill-till’d strong Land. Light-land, having naturally less internal Superficies, seems to require the more Tillage[25] or Dung to enrich it; as when the poor, hollow, thin Downs have their upper Part (which is the best) burnt, whereby all, (except a _Caput Mortuum_) is carried away; yet the Salts of this spread upon that barren Part of the Staple, which is unburnt, divide it into so very minute Particles, that their Pasture will nourish two or three good Crops of Corn: But then the Plough, even with a considerable Quantity of Dung, is never able afterwards to make a Division equal to what those Salts have done; and therefore such burnt Land remains barren. [25] As for puffy Land, which naturally swells up, instead of subsiding, tho’ its Hollowness is much abated by Tillage, yet it is thought little better than barren Land, and unprofitable for Corn: But what we usually call Light-land, is only comparatively so, in Respect of that which is heavier and stronger. And this Sort of Light land becomes much lighter by being ill-till’d; the unbroken Pieces of Turf underneath undissolved, forming large Cavities, increase its Hollowness, and consequently its Lightness: I have often known this Sort of Land despis’d by its Owners, who fear’d to give it due Tillage, which they thought would make it so light, that the Wind would blow it away; but whenever such has been thoroughly till’d, it never fail’d to become much stronger than before; and considering that ’tis till’d with less Expence than very strong Land, it is, for several Sorts of Corn, found to be more profitable than Land of greater Strength and Richness, that is more difficult to be till’d.