30

A DISCOURSE

proper for annuals and exotic plants, which having but little time to live,refuse no afsistances, whilst trees of longer duration care not much foraccelerations.

I shall here then begin with an experiment I have been taught by alearned person of this illustrious Body (Dr. Beal) from whom I have longsince received the choicest documents upon this and many curious subjects.And first, I think it will be evinced, as constant and undeniable, thatamongst the mechanical aids, (wherein stercoration has no hand) that ofpulverizing the earth by contusion, and breaking it with the plough orspade, is of admirable effect, to dispose it for the reception of all the na-tural impregnations we have been discoursing upon. For the earth,especially if fresh, has a certain magnetism in it, by which it attracts thesalt, power or virtue (call it either) which gives it life, and is the reasonof all the labour and stir we keep about it, to sustain us; all dungings,and other sordid temperings, being but the succedaneums to this im-provement, which of all other makes its return of fruit, or whatsoever

else it bears, without imparting any of those ill and pernicious qualitieswhich we sensibly discover from forced grounds, and that not only in theplants which they produce, but in the very animals which they feed andnourish.

I know Laurembergius (somewhere) denies this, and that animals inpreparing chyle, transmute, alter, and insume what is only their properaliment, rejecting all that is superfluous; but as our early asparagus, caul-liflowers, and divers roots, manifestly refute it, so does the taste of theflesh of fowl, and the milk of cattle that feed on the wild garlic, fenny-grafs, and other rank things, not here to insist on their sweet and delicaterelish upon change to a more odoriferous pasture. But to the expe-riment :

Take of the most barren earth you can find, drained, if you please, ofall its nitrous salts, and masculine parts; reduce it to a fine powder,(which may be done even in large proportion, by a rude engine, lettingfall a kind of hammer, or beetle, at the motion of a wheel); let this pul-verized earth, and for the time incefsantly agitated, be exposed, for asummer and winter, to the vicifsitudes and changes of the seasons and in-fluences of heaven: by this labour, and rest from vegetation, you will