Part 4

A Chalk-Pit, contiguous to a Barn, the Area of which being about 40 Perch of Ground, was made clean and swept; so that there was not the Appearance of any Part of a Vegetable, more than in the Barn’s Floor: Straw was thrown from thence into the Pit, for Cattle to lie on; the Dung made thereby was haled away about three Years after the Pit had been cleansed; when, at the Bottom of it, and upon the Top of the Chalk, the Pit was covered all over with Roots, which came from a Witch-Elm, not more than Five or Six Yards in Length, from Top to Bottom, and which was about Five Yards above, and Eleven Yards from the Area of the Pit; so that in three Years the Roots of this Tree extended themselves Eight times the Length of the Tree, beyond the Extremities of the old Roots, at Eleven Yards Distance from the Body: The annual-increased Length of the Roots was near Three times as much as the Height of the Tree.

I’m told an Objection hath been made from hence against the Growth of a Plant’s being in proportion to the Length of its Roots; but when the Case is fully stated, the Objection may vanish. This Witch-Elm is a very old decay’d Stump, which is here called a Staggar, appearing by its Crookedness to have been formerly a Plasher in an old White-thorn Hedge wherein it stands: It had been lopped many Years before that accidental Increase of Roots happened; it was stunted, and sent out poor Shoots; but in the third Year of these Roots, its Boughs being most of them horizontally inclined, were observed to grow vigorously, and the Leaves were broad, and of a flourishing Colour; at the End of the third Year all these Roots were taken away, and the Area being a Chalk-Rock lying uncovered, round the Place where the Single Root, that produced all these, came out of the Bank, no more Roots could run out on the bare Chalk, and the Growth of the Boughs has been but little since.

Wheat, drill’d in double Rows in November, in a Field well till’d before Planting, look’d yellow, when about Eighteen Inches high; at Two Feet Distance from the Plants, the Earth was Ho-plow’d, which gave such Nourishment to ’em, that they recovered their Health, and changed their sickly Yellow, to a lively Green Colour.

So in an Orchard, where the Trees are planted too deep, below the Staple or good Mould, the Roots, at a little Distance from the Stem, are all as near the upper Superficies of the Ground, as of those Trees, which are planted higher than the Level of the Earth’s Surface.

But the Damage of planting a Tree too low in moist Ground is, that in passing thro’ this low Part, standing in Water, the Sap is chill’d, and its Circulation thereby retarded.

One Cause of Peoples not suspecting Roots to extend to the Twentieth Part of the Distance which in reality they do, was from observing these Horizontal-Roots, near the Plant, to be pretty taper; and if they did diminish on, in proportion to what they do there, they must soon come to an End. But the Truth is, that after a few Inches, they are not discernibly taper, but pass on to their Ends very nearly of the same Bigness; this may be seen in Roots growing in Water, and in some other, tho’ with much Care and Difficulty.

In pulling up the aforemention’d Turneps, their Roots seem’d to end at few Inches Distance from the Plants, they being, farther off, too fine to be perceiv’d by ordinary Observation.

I found an extreme small Fibre on the Side of a Carrot, much less than a Hair; but thro’ a Microscope it appear’d a large Root, not taper, but broken off short at the End, which it is probable might have (before broken off) extended near as far as the Turnep Roots did. It had many Fibres going out of it, and I have seen that a Carrot will draw Nourishment from a great Distance, tho’ the Roots are almost invisible, where they come out of the Carrot itself.

By the Piece F Plate 6. may be seen, that those Roots cannot penetrate, unless the Land be open’d by Tillage, &c.

As Animals of different Species have their Guts bearing different Proportions to the Length of their Bodies; so ’tis probable, different Species of Plants may have their Roots as different. But if those which have shorter Roots have more in Number, and having set down the means how to know the Length of them in the Earth, I leave the different Lengths of different Species to be examin’d by those who will take the Pains of more Trials. This is enough for me, that there is no Plant commonly propagated, but what will send out its Roots far enough, to have the Benefit of all the ho’d Spaces or Intervals I in the following Chapters allot them, even tho’ they should not have Roots so long as their Stalks or Stems.

And this great Length of Roots will appear very reasonable, if we compare the Largeness of the Leaves (which are the Parts ordain’d for Excretion) with the Smalness of the Capillary Roots, which must make up in Length or Number what they want in Bigness, being destin’d to range far in the Earth, to find out a Supply of Matter to maintain the whole Plant; whereas the chief Office of the Stalks and Leaves is only to receive the same, and to discharge into the Atmosphere such Part thereof as is found unfit for Nutrition; a much easier Task than the other, and consequently fewer Passages suffice, these ending in an obtuse Form; for otherwise the Air would not be able to sustain the Stalks and Leaves in their upright Posture: but the Roots, tho’ very weak and slender, are easily supported by the Earth, notwithstanding their Length, Smalness, and Flexibility.

Plants have no Stomach, nor Oesophagus, which are necessary to convey the Mass of Food to an Animal: Which Mass, being exhausted by the Lacteals, is eliminated by way of Excrements, but the Earth itself being that Mass to the Guts (or Roots) of Plants, they have only fine Recrements, which are thrown off by the Leaves.

In this, Animal and Vegetable Bodies agree, that Guts and Roots are both injured by the open Air; and Nature has taken an equal Care, that both may be supply’d with Nourishment, without being expos’d to it. Guts are supply’d from their Insides, and Roots from their Outsides.

All the Nutriment (or Pabulum) which Guts receive for the Use of an Animal, is brought to them; but Roots must search out and fetch themselves all the Pabulum of a Plant; therefore a greater Quantity of Roots, in Length or Number, is necessary to a Plant, than of Guts to an Animal.

All Roots are as the Intestines of Animals, and have their Mouths or Lacteal Vessels opening on their outer spongy Superficies, as the Guts of Animals have theirs opening in their inner spongy Superficies.

The Animal Lacteals take in their Food by the Pressure that is made from the Peristaltic Motion, and that Motion caus’d by the Action of Respiration, both which Motions press the Mouths of the Lacteals against the Mass or Soil which is within the Guts, and bring them into closer Contact with it.

Both these Motions are supply’d in Roots by the Pressure occasion’d by the Increase of their Diameters in the Earth, which presses their Lacteal Mouths against the Soil without. But in such Roots as live in Water, a Pressure is constantly made against the Roots by the Weight and Fluidity of the Water; this presses such fine Particles of Earth it contains, and which come into Contact with their Mouths, the closer to them.

And when Roots are in a till’d Soil, a great Pressure is made against them by the Earth, which constantly subsides, and presses their Food closer and closer, even into their Mouths; until itself becomes so hard and close, that the weak Sorts of Roots can penetrate no farther into it, unless re-open’d by new Tillage, which is call’d Hoing.

When a good Number of Single-Mint Stalks had stood in Water, until they were well stock’d with Roots from their two lower Joints, and some of them from three Joints, I set one in a Mint-Glass full of Salt Water; this Mint became perfectly dead within three Days.

Another Mint I put into a Glass of fair Water; but I immers’d one String of its Roots (being brought over the Top of that Glass into another Glass of Salt-water, contiguous to the Top of the other Glass: This Mint dy’d also very soon.

Of another (standing in a Glass of Water and Earth till it grew vigorously) I ty’d one single Root into a Bag, which held a Spoonful of dry Salt, adjoining to the Top of the Glass, which kill’d this strong Mint also. I found that this Salt was soon dissolv’d, tho’ on the Outside of the Glass; and tho’ no Water reach’d so high, as to be within Two Inches of the Joint which produc’d this Root: The Leaves of all these were salt as Brine to the Taste.

Of another, I put an upper Root into a small Glass of Ink, instead of a Bag of Salt, in the Manner above-mention’d; this Plant was also kill’d by some of the Ink Ingredients. The Blackness was not communicated to the Stalk, or Leaves, which inclin’d rather to a yellowish Colour as they died, which seem’d owing to the Copperas.

I made a very strong Liquor with Water, and bruised Seeds of Wild-Garlick, and, filling a Glass therewith, plac’d the Top of it close to the Top of another Glass, having in it a Mint, two or three of whose upper Roots, put into this stinking Liquor, full of the bruised Seeds, and there remaining, it kill’d the Mint in some time; but it was much longer in dying than the others were with Salt and Ink. It might be, because these Roots in the Garlick were very small, and did not bear so great a Proportion to their whole System of Roots, as the Roots, by which the other Mints were poison’d, did to theirs.

When the Edges of the Leaves began to change Colour, I chew’d many of them in my Mouth, and found at first the strong aromatic Flavour of Mint, but that was soon over; and then the nauseous Taste of Garlick was very perceptible to my Palate.

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.