n-y;
li
E X P L A I N E D BY T H E M I C R O S C O P E . 33
m a y be its qualities, is a thing very worthy of trial. How great is the difference PLATE
b e t w e e n this and the Turpent ine of the Vafa interiora, which the fame fpirit clears XIII.
a w a y wi t h the greateft eafe !
C H A P . IV .
O F THE SAP VESSELS.
T T cannot b u t have been ohferved, that in our I l l d Plate, wher e all the p a r t s of a T r e e PLATE
- t are (hewn together, the mof t numerous, as wel l as the largeft aper tures, are in the XIV.
W o o d . All apertures feen b y this view are the ends of velTels cut thro' b y the inftrum
e n t ; and the fize and number of thefe cominaiid the firft attention. Xhey are in
n o T r e e larger than in the Scarlet O a k of America. We have ieen the appearance of a
t h i n Slice in that P late; but it will be proper to give her e an idea of their difpofition
i n a fplit truncheon of the fanie Tree ; fuch as the former . If a fliort cylinder of a
t h r e e years Branch of this O a k , a little macerated, be hol lowed away wi t h a chiflel f o
f a r as t o take out the P i t h and the Corona, it appears as a t P l a t e X IV. Fig. i. The Blea Fig, I.
a n d Bar k are there alfo pufhed .away, fo that the W o o d forms almoft t h e whol e of the
c y l i n d e r ; and it is wonderful to obferve how large a portion of this is occupied by
t h e f e large apertures.
O n the fides of the fpl i t p i e c e w e fee thef e Vef lel s very confpicuous ; for they are very
t h i c k : and it is not di£EcuIt, wi t h fome care and atten Eion, to loofen fcveral of them.
I f a number of thefe, thus feparated, be put into a vial o f rai n water, and frequently
fliook for feveral days, fome will at lengt h be found per fef f l y clean. Thefe are to be
t h e n put into fpirit of wine; and when that has been two or three times changed,
t h e y will be in a condition to be viewed for underftanding thei r ftru£ture. Some of
t h e f e are reprefented, as they appear to a great power of the Microfcope, at Fig. 2. Fig. 2.
w h e r e , notwithilanding all the violence that has been offered them, there will ftill
b e feen i n many of them the remains of valves; by which douhtlefs thefe VeiTcls in
a ftate of nature are divided int o m a n y cells.
I n the Wi l low-leaved Oak thefe Veflels, tho' f omewh a t fmaller, are firmer and more
c o m p a d than in the Scarlet k ind j and having thicker coats, are fitter for examinat
i o n . In the Veflels o f the Scarlet Oak nothing could be feen under the name of a
coat but a me r e membrane, refembling a piece of thin parchment . In thefe, as rep
r e f e n t e d at Fig. 3. the coat is a palpable ring, in which traces of lines fur rounding Fig. 3,
o n e another may be feen; by which 'tis not difficult to underiiand, thatitiscomp
o f e d o f feveral membr anes covering one another. It has h appene d in fome pieces of
7 th e f e
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