Book HL of Trunks. 127 
GA. AP: ik 
Of the Motion and Coutfe of the Aer. 
HE NEXT. enquiry to be made, is, into the 
Motion. and Gourfe of the Aer. Where this 
queltion will firft of all be asked fe. Which way 
the Aer firft enters. the Plant; whether at the 
Trunk, Leaves, and other Parts above ground 5 
orat the Root ?_Ianfwer, That it enters in part, 
at them all. Forthe Reception, as well as Extra- 
million whereof, the Pores are fo very large, in 
x * the Trunks of fome Plants, asin the better fort 
of thick walking Canes, that they are vifible, to a good Eye, with- 
Fete outa Glefs 5 but with a Glafs, the Cave feems, asifit were ftuck top Tab, 19. 
$ full of holes with great Pins: being fo large, asvery well to refem- 
em ble the Pores of the Skin in the end of the Fingers and Bal! of the 
would of Hand. 
the Blade 2. $. Inthe Leaves of Pine, they are likewife through a Glaß, a 
wa very Elegant Show; ftanding all moft exattly, in rank and file, 
shore, throughout the length of the Leaves. , The Figure whereof fhall’ be 
into: by given hereafter, when we come to the Anatomy of the Leaf. 
in. And 3. $. But although the Aer enters, in part, at the Trvzkand other 
ike Blade Parts, efpecially in fome Plants 5 yet its chief entrance, is at the 
Bladder: ‚Root. Evenas fome Parts of Aer, may continually país into the Body 
r, which and Bleod, by the Habit, or Pores of the Skins, but the chief entrance 
the Pipe. hereof, is at the Mouth. And what the Mouth is, to an Animal 3 that 
F D, the the Root isto a Plant. 
y by the 4. $. Again,if the chiefentrance of the Aer,were at the Trunk; then, 
5 bythe before it could be mixed with the sap in the Root, it muft defcend 5 
tho and fo move not only contrary toits own Nature, but likewife in a 
contrary Courfe to theSap, throughout the Plant. Whereas, by its 
Reception at the Root, and fo its Tranfition from thence 5 it hath a more 
natural and ealie motion of Afcent. For while the sap afcends, that 
the Aer, in the fame Plant, fhould continually defcend, cannot reafo- 
nably be fuppofed. 
5. $. The fame is further argued, From the fewneß and fmall- 
nefs of the Diametral Portions in the Trunk, in comparifon with thofe 
in the Root. In which Nature hath plainly defigned the fame, for the 
Separation of the Aer from the Sap,after they are both together received 
> thercinto. So that the Reception and Cowrfe of the Aer, is made on this 
manner following. 
6. $ THE Aer beinga springy Body, it infinuates into all the 
Holes and Cranies of the Earth; and fo is plentifully mixed therewith. 
Whereupon, asthe Sap enters the Root, more or Je Aer (till intrudes 
it fel£ together with it. The Liquid Portion of the Sap, fwells and 
fills up the Succulent Parts of the Barque. The Aery Part, is, as was 
faid, feparated from the into the Diametral Portions, Which 
running 
