OCR Text |
Show TheVegetatim —‘ BookII. Book IIL 6, §. Gri cALPee va are difpofed fo, as to render them more fequaceous to the external Motor. Even as the Clafpers of a Vine, having the like strwdure, have alfo a Motion of Convolution : whereasthe Branches themfelves upon a contrary account, move in firaight Line, TEASRe HE Motions alfo of Trunks are various. Princi. pally Four; fe. Afeending, Defcending, Horizontal, and spiral. Thecaufe of the Afcext of a Plant, isa certain MagnetickCorre/pendence betwixt thé Aer and the Aer-Veffels of a Plant ; the Motion and Tendency whereof, the whole Plant follows. This I have afee > ferted, andI think, clearly demonftrated in my Firft and Second WBa0ks of the Avatomy of Plants. 1 will here add this plain Experiment. i ; 2. §. Take a Box of Moulds, with a hole bored in the bottom, wide enough to admit the stalk ofa Plant, and fet it uponftilts half a yard or more above ground. Then lodg in the Mould fome Plant, for Example a Bea, in fuch fort, that the Root of the Bean {tanding in the Moulds may poynt upwards, the Stalk towards the ground. As the Plant grows, it will follow, that at length the stalk will rife upward, and the Root, on the contrary, arch it {elf downward. Which evidently fhews, That it is not fufficient, that the Root hath Earth to fhoot into, or that its Motioz is only an Appetite of being therein lodged, which wayfoever that be: but that its nature is, though within the Earthalready, yet to change its Pofitiow, and to move Downwards. And {fo likewife of the Tru#k, that it rifes,when a Seed {prouts, out of the Ground, not meerly becaufe it hath an Appetite of being in the open Aer 5 for in this Experimentit is fo already yet now makes a new Motioz upwards. 3. §. BUT although the Natural Motion of the Trunk be to Ajcend s yet is it forced oftentimes to Dejcend. Wherefore, Convolvula’s do not wind by any peculiar Na- ture or Genius, which other Trunks have not 5 but becaufe their Parts Of the Motions of Trunks. CROP of Trunks. 7. §. The Convolution of Plants,hath been obferved only in thofe that Climb. But it feems probable, that manyothers do alfo winds in which, the main stalk, is asthe Axis to the Branches round about. OF which number, I conceive, are all thofe whofe Roots are twilted Motion we obferved in {peaking of the Root. Whetherit be fo, 3 or2Cp1. not the Experiment may eafily be made by tying a Thred upon any of the Branches 5 fetting down the refpeé it then hath to any Quarter in the Heavens : for, if it fhall appear in two or three Months, to have changedits Situation towards fome other Quarters it is a certain proof hereof. And that hereby the Roots of many Plants become twifted ; the Motion beginning in the Stalk, and ending at the bottom of the Root, which ftands always fixed in the fame place. 8. §. The Comvolution of Trunks, is made not one, but divers ways 5 fome moving by South from Ea/t to Wef sand others from We? to Eajft. Whereforeit feemeth, that as the Efficient Canfe of Convolution, is not within the Plant, but external: fo alfo, that it isnot Ove,but that there are Two Great Efficients of this Motion; fc. the Suz and the Aton. Some winding together with the Suz, in its Diurnal Motion, ( or,if the the Earth moves, then, Inclining to the saz) by South from Eaft to Weft. And others winding with the Adoon,in its Monthly Motion, from Weft to Haft. 9g. §. This poflibly, may alfo be one fenfible way of diftinguifhing betwixt Solar, and Luzar Plants, Thus far, in general, of the Motions of Trunks. For the Trumk-Roots growing out of fome Plants near the ground, and fhrinking thereinto, like fo many Ropes, do pluck the Trwzk annually lower and lower into the groundtogether with them as maybe feen in Scrophularia, GHA Var Of the Nature of Timber or Trunks, as they ferve for Mechanick Ufe. Facobea, and manyother Plazts. 4. §. LF thefe Trwk-Roots break out only about the bottom ofthe Trunk, asin the aforefaid Plavts, then the Trunk gradually Defcends into the Earth, andis turned into a Root, But if itbe very flender, and AZ HE laft thing I purpofed to fpeak of, is, Thofe , feveral Qualities of Timber or of Trunks, by which the faid Roots tethering it, as it trails along, to the ground; as in Straw- * Softnefs, Fafineft, Clevefomenefs, Toughne/s, Brittle- they are fitted for Mechanical Ufe. the Truvk-Roots break forth all along it, then it Creeps horizontally 5 5. §. AS totheir Spiral Motion, it is to be noted; That the Wood ofall Conxvolvula’s or Winders, ftands more clofe and round together in or near the Center, thereby making a round, and flender Truzk, To the end, it may be moretractable, to the power of the external Motor, what ever that be: and alfo more fecure from breaking byits winding Motion. As Hardnefs; ~ nes, Durablenefs, or any of the fame Qualities compounded. The ifible Caufes whereof are ob- berry, Cinquefoyl, Mint, Scordium, &c. RY fervable, Partly, in the Struéfure of the feveral Parts; fe. the Infertions; sap-Vefels and Aer-Vefféls 5 a8 to the Number, Size, or Pofition of any of them. And partly, in the Nature of the Parts 5 I mean fuchasis manifef? to fenfe. According to our clear and diftiné& obferving of all which Caufes, we may underftand, Wherefore any Wood is made ufe of for any certain purpofe. And alfo, wherein fitly to apply it to further Ufe. In order to which, 4 A a compleat |