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Show BookHl. The Vegetation 138 compleat Hiftory of the Mechavical Ofes of Vegetables would very much conduce. I fhall for the prefent give fome Jnftances. 2.§. AS First, fome Woods are foft, as Deal, and Sal/ow. Yet from different Caufés. Deal, from the great Porofity of the Woodit felf, or the large Pores among{t the Sap-Veffels, But Sallow, from the great number of der-Feffels {pread all over it. Andtherefore, are both fof, yet will not ferve for the fame purpofes; well wrought upon, which wayfoever you cut it: but ally the white Deal, if it be cut crofS, it tears, and will or work {mooth. ; ; though they Szllow being Deal, efpectnever polifh ae 3. §. Again, in Sa/ow, by the equal {preading of the Aer-Veffels, the Sofine/s 1s equal or alike in all Parts. For which caufe it maketh an excellent Coal for Painters Scribets. Becaufe it doth not only make a light Stroak, but every where certaiz 5 andfo dothnot difturb the even Motion of the Hand. For the fame caufe, shoomukers alfo make ufe of it for their Carving-boards. Becaufe being every where equally foft, it turns not the edge of their Kwives, Which Deal would prefently do 5 becaufe thoughvery foft in fome places, yet in others ‘its hard 5 that is to fay, on the inner Verge of every annual Ring of Wood, where theold Sap-Ve/fels grow much more compact andclofe together. 4. §. AGAIN, fome Woodsare foft, but not fait 5 others are both, as Linn: its Softnefs, depending on the numeroufnefs and equal fpreading of the Aer-Veffels : its Faflvefs, on the clofenef§ of the true Wood, and the fhortnefs, and finallnefs of the Infertions. For which caufe, it is of excellent ufe for many purpofes; andparticularly, for Small Sculptures fach as may fometimes be feen for the Frames of Looking-Glaffes, or of {maller Pidfures in Water-Colours. 5. §. SOME Woods, again, are fa/l, and hard, as Elm. Its hardnefs depending upon the clofenefs of the Wood. Its fafinefs, Partly, upon the fame caufe; and partly, on the fmalnefs of the Lufertions 5 as alfo on the fewnefs of the Aer-Veffels in proportion with the Wood; and on the thwart and crofs Pofition of many of them. Hence it is, that El, of all others, is the moft Crofs-grain'd Timber ; that is, cleaveth fo unevenly, to and fro, according to the crofs Pofitioz of the faid Peffels. 6. §. Hence alfo it cleaveth the moft Difficultl, when it is without any Kwots. Even then, For which reafon it is always ufed, as beft for the Hub of a great Wheel. As alfo for Water-Pipes,and for Pumps. Not becaufe it is the moft dyrable Wood 5 but becanfe it will not fpl#t or crack, either in the working, or afterwards. For y fame reafon, it is ufed for Coffins; that is, becaufe, it will not /plit in working: not becaufe it will endure longeft under ground 5 for Pales are alwaysmade of Ozk. So alfo the Ladles and soles of a Mill-wheel are always made of Elm; asalfo the Keel ofa Boat, fe. left they fhould pit: but the other Parts are made of Ozh. _, 7+ §. It mayhere alfo be noted, That the Planks commonly called » < : : Groaning-Boards, lately expofed, as a kind of Prodigy, to the view and hearing of many People, were of Elw. The Aer-Veffels of this Wood, being, though not more numerous, yet more ample, than in So that upon the application of the Red-hot -Iron, as was ufual, and thereby the Rarifaition of the Aer and Watery Parts in the Timber anyother Timber, 5 every Feffel became, as it were a little Wind-Pipe for their Book IIL of Trunks. their Expiration. And asa great many Drops falling together ina fhowr of Rain; fo a great manyof thefe Pipes playing together, might make a kind ofbig or groaning noyfe. 8. §. AS Elm, of all Woods, is one of the fete? 5 So, on the contrary, of all hard Woods, Oakis the moft Cleavefome, or Jplitteth the moft eafly. The caufe whereof is, partly, the Largene/ of the Infertions 5 and partly, the Diametral or Radiated Pofition of moft of the Aer-#eféls: wpon both which accounts, wherever a crack is once begun, ‘tis eafily continued throughout the Diameter of the Trunk, 9. § AGAIN, fome Woods are hard, fuft, and tough. So is Afb, and efpecially Beech. Hard and faft, from fome ofthe fame Caufes, as Elm. Tough not from the Strufure, but from the Nature ofthe Parts; whofe Principles are united ina more exact proportion. Wherefore Lowdon-Cars have the Rings of their Wheels of Beech; becaule it tears moredifficulty than even A/hit {elf Whence alfo forlarge Screws, there is no Wood like it. But for Sveall Screws, of about an Inch Diameter, Birch isthe beft 5 as being, though notfo hard, yet more tough. 10. §. T HE more Brittle a Woodis, ’tis likewife ufually the more durable. So Oak , which, with refpect to its harduefs, is not 4 tough, but very brittle Wood, is almoft as durable as any. Whereas Beech, Birch, and thelike, although very tomgh; yet for Duration, are of no fervice; for there are no Woodswill rot fooner: and therefore, though ftrong enough, yet unfit tomake any Standing Parts of Building, or of Fur- witure 5 efpecially in wet and moilt places. Becaufe, thefe Woods, having a lefs proportion of Oy/, than there is in Ozk 3 they are apter to imbibe the moifture even of a dank Aer; by which moifture, they either Rot, or breed Worms, which deftroy them. 11. §. HENCE it is, that what we call the Heart of Tiwber, as it is more brittle, fo alfo more durable; fe. Becaufe more Oylie. So that whichis called the sap of Ozk, is much more tough than the Heart, although the Heart be more durable. That is to fay, the older the Wood is, the Watery Parts are the more evapourated, whilft the Oylie {till remaine, asa kind of VinG@ure or Extra in the Wood, Even as wefee, that the older seeds of any one Kind, are more Oyfe thanthofe that are green and young. So that the Oylie or Rofinous Parts of the Sap, are a kind of Embalming to the Heart, or older Part of a Tree, fecuring it from the deftrudctive imprefflions of the Aer, For which. Caufe it is, that Ozh, Yew, Cocus, Guajacum, &c. which are Oylie Woods, have always much Heart, whereas Birch, Alder, Beech, Maple, which are very Unoylie, have never any Heart. 12. §. FROM hencelikewife we may underftand the Caufe of the Toughnefs of Flax: what wecall Flax, being only the Sap-Veffels, or Lignous Fibres of the Barque. And generally, the Barque of any Tree, as of Willow ( whereof are ufually made a fort of Ropes) is very tough. The Veffels being here younger,andlefs Oy/e than in the Wood. Solikewife Hemp, is nothing elfe but the sap-Veffels of the Barque of the Plant {o called. And Scotch-Cloath, is only the Hon/e: 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 refpeGs, better than of Flaxit felf. Becaufe that even Hemp, although it will not make {fe Aa 2 fine |