larger and longer, softer, and of a lighter green. Its Boughs are sewer, the Trunk big-
ger in proportion to its Height, and the Bark a great deal thicker, very light, spungy, and
of an Ash-colour, inclining towards a yellow ; which Bark is the Cork.
Some Naturalists imagine this Cork to be only an Excrescence, or Substance distinct
from the Tree itself, tho' drawing its Nourishment therefrom, like Ivy, Agaric, and se-
veral Species of Fungi ; which Opinion they ground on its having two Barks lying under it,
in common to all Trees ; on the Cork-Tree's being of some Growth before this Substance
comes to be discernable ; on its cracking, flawing, and cleaving into many great Pieces,
while the two Barks underneath remain entire ; and on its being separated and removed
from the Tree, without doing it the least Injury, but on the contrary rendering it more
vigorous and flourishing : Whereas, if not taken away in a certain Time, it either cracks
and falls off itself, or else destroys the Tree.
People that prepare this Substance for Sale, make a perpendicular Incision through the
Length of the whole Tree, and two Incisions transversely, one towards the Top, and the
other at the Bottom of the Trunk. Then carefully clearing off the Cork, without its
being shattered, in large and even Pieces, which renders it of more Value, they soak it
in Water, loading it with Weights to keep it down ; and when sussiciently wetted, lay it
over burning Coals (whereby its Outside becomes blackened) to reduce it to a Flatness ;
and afterwards, to preserve this Flatness, they place it on an exact Level, heaping great
Stones upon it. When perfectly dry, it is made up in Bales for Transportation. Jobn-
ston tells us, that the internal Part of the Cork-Tree is so close and solid it will not swim
in Water, and that in three Years after the Cork has been cleared away, it will be over-
grown with another such-like Covering.
A Structure similar to this discovered by the Microscope in Cork, is likewise to be
found in the Pith of Elder, or almost any other Tree, and also in the Stalks of several
other Vegetables, as Fennel, Hemlock, Carrots, Teasels, Fern, Daucus, Burdock, Rustes,
some Kinds of Reeds, &c. but however with this Difference, that the Pores in these are
ranged the long Way of the Stalk, whereas in Cork they run transverse.
PLATE VIII. FIG. 2.
The Sensible Plant
THE Figure here given is intended to illustrate the Observations made by Dr.
HOOKE, August 9th, 1661, on the Humble and Sensible Plants then growing in
Mr. CHIFFIN'S Garden, St. James's Park ; in the Presence of Lord BROUNKER, Sir
ROBERT MORAY, Dr. WILKINS, Mr. EVELYN, Dr. HENSHAW, and Dr. CLARK.
There were four Plants of the Sensitive Kind, two of which the Doctor distinguishes
by the Name of the Humble Plant, because in them, when the Leaves had closed them-
selves together, either by being gently touched, or if the Sun shine very warm, by only
taking off the Glass that covered them, the tender Sprouts, as if wither'd, hung down-
wards to the Ground.
They were little Shrub-Plants, having a short Stock, that rose about an Inch above the
Earth ; from which several Branches issued, round, strait, and smooth, but with a Couple
of sharp thorny Prickles just under each of the Sprouts that proceeded from them.
The Distance between the Sprouts was usually something above an Inch ; and the End
of each Sprout had generally four Sprigs, two at the Extremity, and one on each Side
just under it. On each of these Sprigs, from its uppermost Side, about eleven Pair of
Leaves grew out, one against another exactly, and neatly set, in such-like Articulations as
when the round Head of a Bone is received into a Socket that assords it an easy Motion.
The Leaves were placed in the most proper Manner to fold together readily ; and when they
closed in Pairs, each Under-Pair folded a little over that above it, as the Picture shews,
where the Sprig is represented closed.
Each Leaf, being almost an oblong Square, grew out from the Sprig at one of the
lower Corners, and received therefrom not only a Spine, (if we may so call it) which pas-
sed through and divided it lengthways, in such a Manner, that the Out-side was broader
than the Inner ; but also small Fibres, passing obliquely towards the opposite broader Side,
and seeming to render it a little muscular, in order to-move the whole Leaf. All the
Leaves and Sprigs were covered with small whitish Hairs.
On touching any of the Sprigs, all the Leaves on that Sprig contracted themselves by
Pairs, and joined their upper Surfaces close together.
On letting a Drop of Aqua-fortis fall on the Sprig, between the Leaves f f, all the
Leaves above, as a, b, c, d, e, shut themselves presently ; those below, as g, b, i, k, l, m,
n, did the same afterwards, by Pairs, successively. Soon after the same Motion began in
