, 8 TH E C O N S T R U C T I O N OF TIMBER
P L A T E ftaiice, only more compadl y put together; and that the reft, which feparates them, ts
nothing more than loofe matter of the famii kirld thrown bfi" from their fides. The
prepared Blea is moft ufefiil in difclofing this j for in frefh fragments the velTels and
this fubrtance feem all one common matter.
Fig. 2. At Fig. 2. a piece of the prepared Wil low Blea is fliewn as it appears before the
a a bk Microfcope : a « are the veffels; i i is the interftitial matter.
T h e velfcls of tlie Blea appear dotted, when feen by lefs powerful glaffes; but here
we perceive thofe dots are fo many oval fwellings, like buds on a young branch ; but
each fwelling has as it were a mouth opening according to its length. Thefe mouths
are innumerable; they appear on every part of the veffels, and ferve the purpofe of
keeping the whole in that continual ftateof moifture which is fo effential to the growt h
Pig. ^ . c c and encreafe of it. Fig. %.cc.
He who would fee this well muft not only make his preparations carefully, but cut
the picces in a fit feafonj either juft before the firft leaves of Spring, or in the Midfummer
Shooting time. Then we fee all the wonders o f this ftniaurei the thoufands
o f mouths which open throughout the courli: of thefe innumerable veffels, to pour
their fluid into the interftititial matter; which fwelling with its ijuanuty, like a fpunge
w i t h water, preffes every part outward and upward into growth and thicknefs. It
were vain to feek them in the Winter Blea; they are (hut by its contraflion and tho'
a little water keeps them in that ftate at thefe times of the year, the ocean could not
at an ill feafon open them. Even in freih pieces of the Blea the very form of thefe
veffels is loft, as foon as their juices leave them. Wherever a piece is carefully and
l i g h t l y torn off, the Microfcope ihews its veffels in their cylindric form at firllj and
fomething of their mouths is vifihle in the more perfefl end of the piece; but where
they have been broken, and their juices let out, they collapfe, and nothing hut a kind
of flat white threads is diftinguifliable. Fig. -¡.abc.
Fig. 3.
a i 1
T h e Wi l low was felcded to fliew the ufe thefe veffels have in the Vegetable Occonomy
; becaufc in that light and loofe wood the mouths are very diftinguilliable : but
there are other kinds in which the general conftnidiion is more evident: the Pear Is
o n e : in this firm wood the veffels are much plainer, though their mouths are lefs ;
they differ alfo in colour from the intermediate matter ; for they are brownilh, while
that is pure white ; and being firm they are lefs liable to contradtion.
I cannot tell whether fome eyes diftinguKli better by the Microfcope than others ;
whether the precife focus is lefs eafily found hy thofe not fo much accuftomed to the
Microfcope s or whether there be any other advantage which that great nurfe of aptnefs,
P r a f l i c e , gives i but to whatever it be owing, I have found it very difficult to fhew
fometimes to others the things myfelf have feen moft clearly : and I have named it in
the prefent objeft becaufe it afforded a remarkable inftance.
T h e Blea Of the frefli W i l l o w appeared to a very careful obfcrver all one fuhftance;
the mouths in the veffels were feen, but not the diftinSion o f Veffels and Flock. A piece
o f the frefli Blea of Pear Tree then was placed in view, and while we looked at it the
natural