This artificial Dust[29], he says, will entertain Plants which refuse Dung, and other violent Applications; and that it has a more nutritive Power than any artificial Dungs or Compost whatsoever: And further, that by this Toil of pulverizing, “’tis found, that Soil may be so strangely alter’d from its former Nature, as to render the harm and most uncivil Clay[30] obsequious to the Husbandmen, and to bring forth Roots and Plants, which otherwise require the lighted and hollowest Mould[31].” [29] Tho’ it may be impossible for the Plough to reduce the whole Staple into so fine Powder, yet the more internal Superficies it makes, the more Dust will be made by the Atmosphere in Proportion; and great Clods perhaps are of no Use to Plants, but by that Dust they let fall, being thence extricated by the insensible Ferment of the nitrous Air; and the Surfaces of this artificial Dust must receive such Operations from the Air, before the utmost Fertility be obtain’d. [30] But I take harsh uncivil Clay to be the least profitable of any to keep in Tillage. [31] To this Dust, _Namque hoc imitamur arando_ ought to be apply’d, and not to _Putre Solum_, which itself needs Tillage, as well as strong Land: But it seems the Antients did not observe the Difference between natural Pores (or Hollowness) and artificial ones, tho’ it is very great; as is shewn in Chap. of _Pasture of Plants_: ’Tis easier indeed to imitate this artificial Dust in _hollow_ than in _strong_ Land. ’Tis to be suppos’d, that the _Indian_ Plants had their due Degrees of Heat and Moisture given them; and I should not chuse to bestow this Toil upon the poorest of Earth in a Field or Garden, tho’ that be the most sure wherein to make the Experiment[32]. [32] This is the most proper Trial of the Effect of Pulveration by _pounding_ and _grinding_; but Land may be so barren, that Plough or Spade may not be sufficient to pulverize it to that Degree, which is necessary to give it the same Fertility, that Pounding in a Mortar, or grinding betwixt Marbles (as Colours are ground), can. I never myself try’d this way of pounding or grinding, because impracticable in the Fields. But I have had the Experience of a Multitude of Instances, which confirm it so far, that I am in no Doubt, that any Soil[33] (be it rich or poor) can ever be made too fine by Tillage[34].