Meadows hold out without Change of Species of Grass, tho’ a Crop be carried off every Year; the Richness of that Soil, with the Help of the Atmosphere, Dung of Cattle in feeding the After-Crop, or else Flooding, from the overflowing of some River, some, or all of which, supply the Place of the Plough to a Meadow.
Woods also hold out beyond Memory or Tradition, without changing Sorts of Trees; and this by the Leaves, and perhaps old Wood, rotting on the Soil annually, which operate as a Manure; because, as has been said, Earth which has once passed any Vessels, is so changed, that, for a long time after, it does not retain its Homogeneity[214] so much as to mix with pure Earth, without fermenting; and by the Descent of the Atmosphere, the Trees shadowing the Soil, to prevent the Re-ascent of what that brings down; all this, resembling Tillage, continually divides the Soil, and renews the Food equal to the Consumption of it made by the Wood.
[214]Not that the Particles of Earth are strictly homogeneous, but that they are much less heterogeneous, before they are altered by Vessels, than afterwards.
And the last Argument I shall attempt to bring for Confirmation of all I have advanced, is that which proves both the Truth and Use of the rest; viz. That when any Sort of Vegetable, by the due Degrees of Heat and Moisture it requires, is agreeable to a Soil, it may, by the new Horse-hoeing Husbandry, be continued without ever changing the Species.
CHAP. XV.
Of Change of Individuals.
Seeds, in their natural Climate, do not degenerate, unless Culture has improved them; and then, upon Omission of that Culture, they return to their first natural State.
As the Benefit of changing of Species of Seeds is from Difference of Tillage, so the Benefit of changing Individuals of the same Species appears to be from those Causes which are, generally, themselves, the Effects of different Climates, such as Heat and Moisture, which may also vary very much in the same Latitude and Neighbourhood; as the same Mountain in the Country of the Mogul (related by Mr. Evelyn, from Monsieur Bernier), on the South Side produces Indian Plants, and on the North Side European Plants, from different Exposures; and some Land, retaining Water longer, is colder; some, suffering it to pass down quicker, and by the Nature and Figure of its Parts, causes such a Refraction and Reflexion of the Sun’s Rays, which give a great Warmth, as in Sand, and gravelly Grounds, that are well situate, and have an under Stratum of some Sort of hollow Matter, next under the Staple[215], or upper Stratum, wherein the Plough is exercised.
[215]This hollow Matter lets the Water pass down the sooner from the Surface, whereby the Staple or the Ground becomes the drier, and consequently warmer.
This beneficial Change of Individuals seems rather to be from the forementioned Causes, than from Change of Food; and these Causes shew their Efficacy, chiefly in the Generation or Fœtation of those Seeds; as Flax-seed brought from Holland, and sown here, will bring as fine Flax as there; but the very next Generation of it coarser, and so degenerating gradually, after Two or Three Descents, becomes no better than the common ordinary Sort; yet its Food is the same, when the Flax is fine, as when ’tis coarse.
And so it is, when Individuals of Wheat are changed: So Silk-worms, hatched and bred in France, of Eggs or Seed brought from Italy, will make as fine Silk as the Italian; but the Eggs of these laid in France and their Issue, will make no better Silk than the French; though their Food be from Leaves of the same Mulberry-trees, when they make fine Silk and coarse: Therefore ’tis from the Climate, where the Eggs are impregnated, not where they have their Incubation or Food, when hatched, and fed to their Lives End, that this Difference happens.