Book I. of Pook 


lated. And this being dilated, the Cortical Body alfo, muft needs be 
énferted , and is therefore'in proportion always, more or lef, finaller 
here in the Trazk, than inthe Root. And as the Cortical Body leffens, 
fo the Pith will be enlarged, and by the fame proportion is here 
greater. And the Pith being enlarged it felf, its Pores ( the Lignous 
Body, upon its dilatation, as it were tentering and ftretching out all 
their fides) muft needs likewife be enlarged with it; and according- 
ly, are ever greater in the Pith of the Traek, than of the Root. 
And the dilatation of the Ligvous Body {till continued, it follows, 
that whereas the Pith defcendent in the Root, is not only in propor- 
tion lefs and lefs, but alfo in the fmaller extremities thereof, and fome- 
times higher, altogether abfent: Contrariwife, in the Trunk, it is 
not only continued to its top and fmalleft Twigs, but alfo there, in 
proportion, equally ample with what it is in any other inferiour 
art. 
: 23. §. But although the opennefi of the Aer permitting, be all- 
ways alike; yet the Energy of the Sup effecting, being different 5 as 
therefore that doth, the dilatation of the Truk , will alfo vary. If 
that be lefs, fo is this; as in the Trunks of moft Trees: If that be 
greater, fo thiss asin Herbs is commons the Liguous Body being ufu- 
ally fo far dilated, that the utmoft Shootings thereof may eafily be 
feen to jut out, and adjoyn tothe Sk. And ifthe sep be ftill of 
greater energy, it fo far dilates the Ligvons Body, as not only to am- 
plifie the Pith and all its Pores; but alfo fo far to ftretch them out, 
as to make them tear. Whereupon either running again into the 
Cortical Body, or fhrinking up towards it, the Trunk thus fometimes 
becomes an hallow Stalk, the Pith being wholly, or in part voided. 
But generally it keeps entire; and where it doth, the fame proporti- 
on and refpect to the Ligveus and Cortical Bodies, as is faid. The 
Confequences of all which will be, the Strength of the Trunk, the Se- 
curity and Plenty of the Sap, its Fermentation will be quicker, its Di- 
feribution more effetual, and its Advancement more fafficient. 
24. §. Firft, the Erect Growth and Strength of the Trunk; this 
being, by the pofition of its feveral Parts, effected : for befides the flen- 
dering of the Zrunk ftill towards the top, the Circwmferential pofition 
of the Lignows Body, likewife is, and that eminently, hereunto fubfervi- 
ent. So that as the Ligwows, Body, inthe fmaller parts, of the Root 
ftanding Central, we may thence conceive and fee their pliablenef to 
any oblique motion 5 fo here, on the contrary, the Ligvous Body {tan- 
ding wide, it thus becomes the Strength of the'Trx#k, and moft ad- 
vantageous to its PerpendicularGrowth. We fee the fame Defign in 
Bones and Feathers: The ftrongeft Boxes, as thofe in the Legs, are 
hollow. Now fhould we fuppofe the fame Boze, to be contraéted in- 
to a Solid; although now it would be no heavier, and in that re- 
fpe&, asapt for motion 5 yet would it have far lef ftrength, than as 
its Parts are dilated to a Circumferential poftare. And fo for Quills, 
which, for the fame Reafons, in fubferviency to flying, as they are ex- 
ceeding light 5 So, in comparifon with the thinnefs of their Sides, they 
are very f{trong, and much lefs apt to bend, than if contraéted into a 
Solid Cylinder. We fee it not only in Nature, but Art, For hence it 
is, that Foywers and Carpeaters unite and fet together their Timber- 
pieces and feveral Works oftentimes with double Joynts ; which, al- 
though 
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