S 6
P L A T E
XXXV.
/ £
J,
T H E C O N S T R U C T I O N OP TIMBER.
B O O K V.
OF PARTICULARITIES IN THE VESSELS OF TREES,
C H A P . I.
T H E R E pARTICUtARITIES is no part of the Vegetable IN THE VASA Conftruftion P ROPRIA fo little EXT liable ERIORA.to variation, as
•far as I have yet ieen, as this of the Vafa propria. Their form and difpofition
i n the Oak has been given already j and that is in almoft every Tree the true ftate of
t h e i r arrangement. They are often too fmall to be very obfervable: the eye frequently
mifles them, unlefs affifted by fome new power of glalTes j and when it finds them,
they are juf t what they were in kinds that oifered t h em more eafily to the view: only
in the American Cyprefs, reprefented at Plate XXXV. I have feen a difference: and
'tis there indeed a great one. In other inftances they are packets of little VeiTcls}
tender, thin in the coat, and filled with fome tough juice. In this Tree they are
fingle, a, their coats are firm, they rife u p above the furface of the reft of the parts
when the fetSion has lain a little while, (that is, they contradl lefs than the other
parts, which therefore recedc from them,) and they are more than filled; (at leait
'twas fo at the feafon, April 17, when I examined them) they run over wi t h a moft
pure and perfeft balfam, and ihew their fides, tho' thick, unable to reiift the force with
w h i c h this has been thrown up into them : for they appear burft in many places.
For the reft, this Tree is not without its particularities. The Blea, c, rifes in
c o n e s ; and the Bark, d, forces itfelf between them; but does not penetrate the Wood,
as in fome other inftances. The texture of the Wood, e, is very delicate, and the
Sap-Veflels, f , are numerous, but not large. The Corona, g, in this Tree is fmall,
but very corredly defined j and the Pith, h, is extremely thin.
C H A P .