And I am apt to think, that this Sort of Light-land acquires more Cement, by having its _external_ Superficies often changed, and exposed to the Dews, and other Benefits of the Atmosphere, as well as by the Increase of (its _internal_ Superficies, which is the Surfaces of all the divided Parts of Earth, or) the Pasture of Plants; the one being augmented by the other; _i. e._, that into the more Parts the Earth is broken, the more Cement will it attain, from the Sulphur, which is brought by the Dews. Artificial Pores cannot be too small, because Roots may the more easily enter the Soil that has them, quite contrary to natural Pores; for these may be, and generally are, too small, and too hard for the Entrance of all weak Roots, and for the free Entrance of strong Roots. Insufficient Tillage leaves strong Land with its natural Pores too small, and its artificial ones too large. It leaves Light-land, with its natural and artificial Pores both too large. Pores that are too small in hard Ground, will not easily permit Roots to enter them. Pores that are too large in any Sort of Land, can be of little other Use to Roots, but only to give them Passage to other Cavities more proper for them; and if in any Place they lie open to the Air, they are dry’d up, and spoil’d, before they reach them. For fibrous Roots (which alone maintain the Plant; the other Roots serve for receiving the Chyle from them, and convey it to the Stem) can take in no Nourishment from any Cavity, unless they come into Contact with[26], and press against, all the Superficies of that Cavity, which includes them; for it dispenses the Food to their Lacteals by such Pressure only: But a fibrous Root is not so press’d by the Superficies of a Cavity whose Diameter is greater than that of the Root. [26] Roots cannot have any Nourishment from Cavities of the Earth that are too large to press against them, except what Water, when ’tis in great Quantity, brings to them, which is imbibed by the gentle Pressure of the Water; but when the Water is gone, those large Cavities being empty, the Pressure ceases; and this is the Reason, that when Land has few other but such large Cavities, the Plants in it always suffer more by dry Weather, than in Land which by Dung or Tillage has more minute and fewer large Cavities. There may be some Moisture on the Superficies of large Cavities; but without Pressure the fibrous Roots cannot reach it; and very little or no Pressure can be made to one Part of the Root’s Superficies, unless the Whole that is included be pressed.