I observ’d, that when the Mint had stood in a Glass of Water, until it seem’d to have finish’d its Growth, the Roots being about a Foot long, and of an earthy Colour, after putting in some fine Earth, which sunk down to the Bottom, there came from the upper Joint a new Set of white Roots, taking their Course on the Outside of the Heap of old Roots downwards, until they reach’d the Earth at the Bottom; and then, after some time, came to be of the same earthy Colour with the old ones.
Another Mint being well rooted from Two Joints, about Four Inches asunder; I plac’d the Roots of the lower Joint in a deep Mint-Glass, having Water at the Bottom, and the Roots of the upper Joint into a square Box, contriv’d for the Purpose, standing over the Glass, and having a Bottom, that open’d in the Middle, with a Hole, that shut together close to the Stalk, just below the upper Joint; then laying all these upper Roots to one Corner of the Box, I fill’d it with Sand, dry’d in a Fire-shovel, and found, that in one Night’s time, the Roots of the lower Joint, which reach’d the Water at the Bottom of the Glass, had drawn it up, and imparted so much thereof to those Roots in the Box above, that the Sand, at that Corner where they lay, was very wet, and the other three Corners dry. This Experiment I repeated very often, and it always succeeded as that did.
And for the same Purpose I prepar’d a small Trough, about two Foot long, and plac’d a Mint-Glass under each End of the Trough; over each Glass I plac’d a Mint, with half its Roots in the Glass, the other half in the Trough: The Mints stood just upon the Ends of the Trough. Then I cover’d these Roots with pulveriz’d Earth, and kept the Glasses supply’d with Water; and as oft as the white fibrous Roots shot thro’ the Earth, I threw on more Earth, till the Trough would hold no more; and still the white Fibres came thro’, and appear’d above it; but all seem’d (as I saw by the Help of a coarse Microscope) to turn, and when they came above-ground, their Ends enter’d into it again. These two Mints grew thrice as large as any other Mint I had, which were many, that stood in Water, and much larger than those which stood in Water with Earth in it: They being all of an equal Bigness when set in, and set at the same time. Tho’ these two, standing in my Chamber, never had any Water in their Earth, but what those Roots, which reach’d the Water in the Glasses, sent up to the Roots, which grew in the Trough. The vast Quantity of Water these Roots sent up, being sufficient to keep all the Earth in the Troughs moist, tho’ of a thousand times greater Quantity than the Roots which water’d it, makes it probable, that the Water pass’d out of the Roots into the Earth, without mixing at all with the Sap, or being alter’d to any Degree. The Earth kept always moist, and in the hot Weather there would not remain a Drop of Water in the Glasses, when they had not been fresh supply’d in two Days and one Night; and yet these Roots in the Glasses were not dry’d, tho’ they stood sometimes a whole Day and Night thus in the empty Glasses. These two Mints have thus liv’d all one Summer.
Remarks on the Mints, &c.
Tho’ the Vessels of Marine Plants be some ways fortify’d against the Acrimony of Salt, as Sea-fish are, yet the Mints all shew, that Salt is poison to other Plants.
The Reason why the Salts in Dung, Brine, or Urine, do not kill Plants in the Field or Garden, is, that their Force is spent in acting upon, and dividing the Parts of Earth; neither do these Salts, or at least any considerable Quantity of them, reach the Roots.
I try’d Salt to many Potatoes in the Ground being undermin’d, and a few of their Roots put into a Dish of Salt-water, they all died sooner or later, according to their Bigness, and to the Proportions the Quantity of Salt apply’d did bear to them.
By the Mints it appears, that Roots make no Distinctions in the Liquor they imbibe, whether it be for their Nourishment or Destruction; and that they do not insume what is disagreeable, or Poison to them, for lack of other Sustenance; since they were very vigorous, and well fed in the Glasses, at the time when the most inconsiderable Part of their Number had the Salt, Garlick, and Ink offer’d to them.
The sixth Mint shews, that when new Earth is apply’d to the old Roots, a Plant sends out new Roots on Purpose to feed on it: And that the more Earth is given it, the more Roots will be form’d, by the new Vigour the Plant takes from the Addition of Earth. This corresponds with the Action of Hoing; for every time the Earth is mov’d about Roots, they have a Change of Earth, which is new to them.
The seventh Mint proves, that there is such a Communication betwixt all the Roots, that when any of them have Water, they do impart a Share thereof to all the rest: And that the Root of the lower Joint of this Mint had Passages (or Vessels) leading from them, through the Stalk, to the Roots of the upper Joint; tho’ the clear Stalk (through which it must have pass’d) that was betwixt these two Joints, was several Inches in Length.