
Book IIL of Trunks. 


their Expiration. And asa great many Drops falling together in a fhowr 
of Rain; fo.a great many of thefe Pipes playing together, might make 
a kind of big or groaning noyfe. 
8. §. AS Elm, of all Woods, is one of the fifteff 5 So, on the 
contrary, of all hard Woods, Oak is the molt Cleavefome, or fplitteth 
the moft eafily. ‘The caufe whereof is, partly, the Largeneft of the 
Infértions 5 and. partly, the Diametral or Radiated Polition of moft of 
the Aer-seffels: wpon both which accounts, wherever a crack is once 
begun, ‘tis eafily continued throughout the Diameter of the Trvwk., 
9. § AGAIN, fome Woods are hard, feft, and tough. So is 
Afh, andefpecially Beech. Hard and faft, from fome of the fame Cau- 
fes, as El. Tough not from the struéfure, but from the Nature of the 
Parts 5, whofe Principles are united ina more exact proportion. Where- 
fore London-Cars have the Rings of their Wheels of Beech 3 becaufe it 
tears more difficulty than even Ajhit felf. Whence alfo for large Screws, 
there is no. Wood like it. But for Small Screws, of about an Ixch Diame- 
ter, Birch isthe belt; as being, though not fo hard, yet more tough. 
10. § THE more Brittle a Wood is, tis likewife ufually the more 
durable. So Oak, which, with refpect to its harduefs, is not a tough, but 
very brittle Wood,. is almoft as durableas any. Whereas Beech, Birch, 
and the like, although very tough; yet for Duration, are of no fervice 5 
for there.are no Woods will rot fooner : and therefore, though {trong 
enough, yet unfit tomake any Standing Parts of Building, or of Fur- 
niture ; efpecially in wet and moift places. Becaufe, thefe Woods, 
having a lefs proportion of Oyl, than there is in Ozk 5 they are apter 
to imbibe the moifture even of a dawk Aer; by which moifture, they 
either Rot, or breed Werms, which deftroy them, 
11. §. HENCE) it is, that what we call the Heart of Tin- 
ber, as it! is more brittle, fo alfo more durables fc. Becaufé more 
Oylie. So that which is called the sap of Oak, is much more tovgh than 
the Heart, although the Heart be more durable. That is to fay, the 
olderthe Wood is, the Watery Parts are the more evapourated, whilft 
the Oyize (till remaine, asa kind of Timéure or Extra in the Wood. 
Even as we fee, that the older Seeds of any one Kind, are more Oy- 
He thanthofe that are green and young. So that the Oyle or Rofizous 
Parts of the Sap, are a kind of Ezbalming to the Heart, or older Part 
of a Tree, fecuring it from the deftrudtive impreffions of the Aer, For 
which Caufé it is, that Oak, Tew, Cocus, Guajacum, &c. which are 
Oylie. Woods, have always much Heart, whereas Birch, Alder, Beech, 
Maple, which are very Unxoylie, have never any Heart. 
12. §. FROM hencelikewife we may underftand the Caufe of 
the Toughnefs of Flax « what we call Flax, being only the sap-Vefels, 
or Ligwous Fibres of the Bargue. And generally, the Bargue of any 
Tree, as of Willow (whereof are ufually made a fort of Ropes) is 
very tough. The Veffels being here younger, and lefs Oy/e than in the 
Wood. Solikewife Hemp, is nothing elfe but the sap-Vefels of the 
Barque of the Plant fo called. And Scotch-Cloath, is only the Houje- 
wifery of the fame Parts of the Barque of Nettle, 
13. §. WHENCE itis very probable, that’ there are many 
other Plants, as well as the above named, whereof. might be made 
good Tow. And of fome, efpcially in fome refpeds, better than of 
Flax ifelf Becaufe that even Hemp, although it will not ieee {fo 
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