T H E CONS TRUCT ION OF TIMBER
P L A T E Vegetable Oeconomy j fince from !t arife the branches, and encreafe of the tree : no
111. Vegetable is without it; nor have the figures of thofe, who have drawn the parts
of Plants, failed to exhibit it, as a portion different from all others j yet, till this occafion,
it never had a name. It is in the Oak an undulated circle i and the undulations
of all the other circles take their rife from it, It contains diüinflly two kinds of
i veifels; a larger, t , which are pale; and a fmaller, which are browner; together
with an intermediate matter : this is not vafcular, but compofed, as the bark, of filmy
bladders. The larger order of veffels contain a fomewhat acid juicc; the fmaller or -
der, a very auftere liquor ; and the intermediate fubftance, pure water.
- / /reprefents the Pith. This takes the fame undulated form in its outline as the Corona,
which every way inclofes it: its appearance is very pretty : it feems to confift
of rings, with fingle, double, and interfefling outlines i but the reality is otherwife.
The whole is a compages of little, hollow, white films, arranged, fide by fide, acrofs
the entire fpace, and having others of the fame kind, and form, beneath them;
through the whole length of the Shoot.
m lit iliews the entire Slice in its natural hignefs.
Such is the conftruflion of a Shoot, and fuch the difpofition of the feveral parts !
we may now proceed to their feparate examination.
C H A P . II.
T H E MANNER OF OBTAINING THE PARTS OF A S i lOOT SEPARATE.
TH E enquiry into the ftruitureof each feparate part of the Shoot, is a matter of
much greater care and attention than the former: I will not fay, of difficulty;
for every thing yields to a determined mind : but time and application will be required.
The method I have ufed is this:
In the beginning of April I take a quantity of young branches, from the Scarlet Oak,
and other trees; thefe are firft cut into lengths, of the growth of different feafons; and
then part are left entire, part fplit, and the reft quartered. In this ftate they are put into
a wicker balket, with large openings, or of loofe work; and a heavy ftone is put in with
them: a rope is tied to the handle of the baficet, and it is thrown into a brook of running
water ; at times it is taken up, and expofed a little to the air; it is frequently (hook
about under water, to wafc off filth; and once in ten days the flicks are examined.
By
E X P L A I N E D BY T H E MICROSCOPE. u
By degrees, the parts loofen from one another ; and, by gentle rubbing in a bafon PLATE
of water, juft warm'd, they will be fo far feparated, that a pencil bruih will perfedt
the bufinefs; and afford pieces of various fize, pure, diftinft, and clean. One part
will, in this way, feparate at one time, and another at another: but by returning
the flicks to the water, and repeating the operation, in a,courfe of four or five weeks,
every part may be obtained diftinft. They are beft examined immediately; but as
one wiflies to preferve them for repeated enquiries, it may be done in this manner.
DIffolve half an ounce of Alum in two quarts of water : drop the pieces, tlius feparated,
for a few moments, into this folution ; then dry them upon paper, and put
them up, in vials of Spirit of Wine. Nothing but Spirit of Wine can preferve thefe
tender bodies; and, till I found this method of hardening them firft, that liquor often
deflroyed them.
C H A P . in.
OF THE CONSTRUCTION OF THE RIND.
IT has been cuftomary to diflinguiih the two outermoft coats of a. tree by the names
Outer, and Inner Rind ; but as we have the two words. Rind and Bark, in common
ufe, it may be more diftinft to apply one of them to the one, and tlie other to the other.
The Rind, or outermoft coat, being feparated from the reft, and cleaned, appears be-,
fore the Microfcope like a piece of white cobweb. It is to be examined, if freih, in
water j if preferved, in fome of the Spirit wherein it is kept j being laid in a litde ciftern,
hollowed in a Cip of ground glafs: the happieft view of it will be had by combining
the fixth and feventh magnifiers of the Microfcope here figured.
Although this Rind be by far the thinneft of all the parts, yet it is compofed of feveral
coats 3 one laid clofely over another, and all of the fame kind : the great difficulty
is to obtain one of them abfolutely feparate. In that ftate it appears fcarce
more than a fiiadow, or a mere delineation of lines upon the glafs j but without this,
its true conftruftion cannot be known.
The piece of Rind reprefented at Fig. i, in Tab. IV. ihews the neceffity of this exa£t- Fig. J.
nefs : the part of it at a is one coat onlyi at i , two lie over one another; at c, three : a b c
in thefe two lad portions there is a great deal of confufion : but at a the real ftruc- a
ture of the part is perfedtly diftinft. It confifts of a feries of longitudinal veffels, and
D a filmy