Part 7

The only Difference of Soil (except the Richness) seems to be the different Heat and Moisture it has; for if those be rightly adjusted, any Soil will nourish any Sort of Plant; for let Thyme and Rushes change Places, and both will die; but let them change their Soil, by removing the Earth wherein the Thyme grew, from the dry Hill down into the watry Bottom, and plant Rushes therein; and carry the moist Earth, wherein the Rushes grew, up to the Hill; and there Thyme will grow in the Earth that was taken from the Rushes; and so will the Rushes grow in the Earth that was taken from the Thyme; so that ’tis only more or less Water that makes the same Earth fit either for the Growth of Thyme or Rushes.

As I have said in my Essay, That a Soil being once proper to a Species of Vegetables, it will always continue to be so; it must be supposed, that there be no Alteration of the Heat and Moisture of it; and that this Difference I mean, is of its Quality of nourishing different Species of Vegetables, not of the Quantity of it; which Quantity may be alter’d by Diminution or Superinduction.

So for Heat; our Earth, when it has in the Stove the just Degree of Heat that each Sort of Plants requires, will maintain Plants brought from both the Indies.

Plants differ as much from one another in the Degrees of Heat and Moisture they require, as a Fish differs from a Salamander.

Indeed Misletoe, and some other Plants, will not live upon Earth, until it be first alter’d by the Vessels of another Plant or Tree, upon which they grow, and therein are as nice in Food as an Animal.

There is no need to have Recourse to Transmutation; for whether Air or Water, or both, are transform’d into Earth or not, the thing is the same, if it be Earth when the Roots take it; and we are convinced that neither Air nor Water alone, as such, will maintain Plants.

These kind of Metamorphoses may properly enough be consider’d in Dissertations purely concerning Matter, and to discover what the component Particles of Earth are; but not at all necessary to be known, in relation to the maintaining of Vegetables.

CHAP. III.

Of PASTURE of PLANTS.

Cattle feed on Vegetables that grow upon the Earth’s external Surface; but Vegetables themselves first receive, from within the Earth, the Nourishment they give to Animals.

The Pasture of Cattle has been known and understood in all Ages of the World, it being liable to Inspection; but the Pasture of Plants, being out of the Observation of the Senses, is only to be known by Disquisitions of Reason; and has (for ought I can find) pass’d undiscover’d by the Writers of Husbandry.

When Writers of Husbandry, in discoursing of Earth and Vegetation, come nearest to the Thing, that is, the Pasture of Plants, they are lost in the Shadow of it, and wander in a Wilderness of obscure Expressions, such as Magnetism, Virtue, Power, Specific Quality, Certain Quality, and the like; wherein there is no manner of Light for discovering the real Substance, but we are left by them more in the Dark to find it, than Roots are when they feed on it: And when a Man, no less sagacious than Mr. Evelyn, has trac’d it thro’ all the Mazes of the Occult Qualities, and even up to the Metaphysics, he declares he cannot determine, whether the Thing he pursues be Corporeal or Spiritual.

The Ignorance of this seems to be one principal Cause, that Agriculture, the most necessary of all Arts, has been treated of by Authors more superficially than any other Art whatever. The Food or Pabulum of Plants being prov’d to be Earth, where and whence they take that, may properly be called their Pasture.

By the Pasture is not meant the Pabulum itself; but the Superficies from whence the Pabulum is taken by Roots.

This Pasture I shall endeavour to describe.

’Tis the inner or (internal) Superficies of the Earth; or which is the same thing, ’tis the Superficies of the Pores, Cavities, or Interstices of the divided Parts of the Earth, which are of two Sorts, viz. Natural and Artificial.

This Pasture of Plants never having been mentioned or described by any Author that I know of, I am at a loss to find any other Term to describe it by, that may be synonymous, or equipollent to it: Therefore, for want of a better, I call it the inner, or internal Superficies of the Earth, to distinguish it from the outer or external Superficies, or Surface, whereon we tread.

Inner or internal Superficies may be thought an absurd Expression, the Adjective expressing something within, and the Substantive seeming to express only what is without it; and indeed the Sense of the Expression is so; for the Vegetable Pasture is within the Earth, but without (or on the Outsides of) the divided Parts of the Earth.

And, besides, Superficies must be joined with the Adjective Inner (or Internal) when ’tis used to describe the Inside of a thing that is hollow, as the Pores and Interstices of the Earth are.

The Superficies, which is the Pasture of Plants, is not a bare Mathematical Superficies; for that is only imaginary.

By Nature, the whole Earth (or Soil) is composed of Parts; and, if these had been in every Place absolutely joined, it would have been without Interstices or Pores, and would have had no internal Superficies, or Pasture for Plants: but since it is not so strictly dense, there must be Interstices at all those Places where the Parts remain separate and divided.

For were the Soil as dense as Glass, the Roots or Vegetables (such as our Earth produces) would never be able to enter its Pores.

These Interstices, by their Number and Largeness, determine the specific Gravity (or true Quantity) of every Soil: The larger they are, the lighter is the Soil; and the inner Superficies is commonly the less.

The Mouths, or Lacteals, being situate, and opening, in the convex Superficies of Roots, they take their Pabulum, being fine Particles of Earth, from the Superficies of the Pores, or Cavities, wherein the Roots are included.

And ’tis certain, that the Earth is not divested or robb’d of this Pabulum, by any other Means, than by actual Fire, or the Roots of Plants.

For, when no Vegetables are suffer’d to grow in a Soil, it will always grow richer. Plow it, harrow it, as often as you please, expose it to the Sun in Horse-Paths all the Summer, and to the Frost of the Winter; let it be cover’d by Water at the Bottom of Ponds, or Ditches; or if you grind dry Earth to Powder, the longer ’tis kept exposed, or treated by these or any other Method possible (except actual Burning by Fire); instead of losing, it will gain the more Fertility.

These Particles, which are the Pabulum of Plants, are so very minute and light, as not to be singly attracted to the Earth, if separated from those Parts to which they adhere, or with which they are in Contact (like Dust to a Looking-Glass, turn it upwards, or downwards, it will remain affixt to it), as these Particles do to those Parts, until from thence remov’d by some Agent.

As to the Fineness of the Pabulum of Plants, ’tis not unlikely, that Roots may insume no grosser Particles, than those on which the Colours of Bodies depend; but to discover the greatest of those Corpuscles, Sir Isaac Newton thinks, it will require a Microscope, that with sufficient Distinctness can represent Objects Five or Six hundred times bigger, than at a Foot Distance they appear to the naked Eye.