Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/782

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pofetl in the uterus ; and {hews that, as no part is by anato- mifts allowed more delicate, fo there is fcarce any cafe in ■which nature and good conftitution cannot make a cure. It is to be obferved alfo, in regard to this woman, that in the fourteenth month after her fall, (he found herfelf again with child ; but this ended in a mifcarriage.

Several bundles of mufcular fibres enter the ftructure of the Womb. Ruyfch mentions an orbicular mufcle at its fundus ; which, Mr. Monro fays, he has alfo feen. ' Vide Med. Eft. Edinb. vol- 2. p. 12S. and Ruyfch, Epiftols de mufcul. in fund. Uteri.

The human uterus has numerous orifices of veflels opening into its cavities, to pour out liquors there. Towards the fundus of the Womb efpecially, thefe orifices are found to be the extremities of canals that come out from larger cavities, lodged within the iubftance of the Womb. Thefe cavities are commonly called finufes. See the article Sinuses of the Womb.

It is aqueftion among anatomifts and phyfiologifls, whence the cavity in the Womb is formed, which in the Taft months con- tains the infant, the greateft part of the waters, and all the fecundities, except the placentia ? As to which, the curious may confult the learned Dr. Thomas Simp/on s Diflertation in the Medic. Eff Edinb. vol. 4. art. 13.

WOMEN (Cycl,)— Lying-in Womeu. See the articles Ly- ing-/;/, Delivery, Lochia, and Mola.

Pregnant Women. See the articles Preg nancy and Gra- viditas.

WOOD {Cycl.) — Tbeftructure and organization of Wood is a fubject on which many have employed their thoughts ; but perhaps none with greater fuccefs than the celebrated Mon- fieur Buffon, of the Royal Academy of Sciences at Pa- ris.

This gentleman obferves that the organization of Wood is yet unknown in all its parts ; and that though the world is greatly ' indebted to the observations of Grew, Malpighi, and Hales, yet, when lie entered on the fubject, he found there was much . more unknown than known, and determined to obferve, from its firft ftate, the growth of trees, and the formation of their woody part.

' The feed of a tree, fuppofe an acorn, if put into the earth in the fpring feafon, produces, after a few weeks, a tender fhcot, of an herbaceous ftructure, which enlarges, extends . itfelf, and hardens by degrees, and in the firft year's growth, has in it a {lender filament of a woady fubftance. At the ex- tremity of this young tree there is a little button formed, which opens the next year into leaves, and from which there is pro- pagated a fecond moot, in all refpects like that of the firft year, except that it is more vigorous, grows fafter, and har- dens much more confiderably. This is alfo terminated by a button like that of the precedent year, and in this is contained the (hoot of the third year; and in this manner is the growth of the tree carried on, till it has acquired its whole height. . Each of thefe buttons is a fort of feed, which contains the flioot of the fucceeding year, juft as the feed itfelf did that of the firft : and the growth of a tree in height is carried on therefore by a feries of annual productions, exactly like one -another, and the full-grown tree is, though perhaps a hundred foot high, compofed only of a number of ihort trees, joined end to end, the longeft of which is not above two fuot in length. Thefe little trees ofthefeveral years never at all alter then- height or length, or even their thicknefs; they remain even in a tree of a hundred years old, of their original length and diameter, and fuffer no change, but in becoming harder. This then is the manner in which trees grow in height; how they grow in thicknefs is next to be inquired into. The button, which makes the funimit of the tree of the firft year, draws it nourishment through the very fubftance of that little tree ; but the principal tubes or veflels which feive to convey the fap, are placed between the bark and the woody filament.

The action of this fap in moving, dilates and enlarges thefe vcfTels, while the button, in raifiny; itfelf up ingrowth, elon- gates them ; the fap alfo, in continually patting them, leaves behind it certain fixed parts, which augment the folidity. Thus 'the fecond year's little tree contains in its middle a woody filament in form of an elongated cone, which is the production of the Wood of a former year, and a woody bed for it, which is alfo of a conic fhape, and which furrounds the firft filament, and reaches beyond it in length ; and this is the production of the fecond year. The third bed forms itfelt altogether like the fecond, and all the fucceeding ones are formed by the fame law, and in the fame order, and envelope one another in a continued fuccefli on or feries, fo that a large tree is compofed of a number of woody cones, which enfold, cover, and enve- lop one another, as the tree increafes in thicknefs. "When the tree comes to be cut down, one eafily counts, in a tranfverfe fection of the trunk, the number of thefe cones, the feetions of which make fo many concentric circles ; and the age of the tree is known by the number of thefe circles, for they are diftinctly feparate from one another ; in a vigorous and ' well-grown oak, thefe lines are each of a fixth of an inch or more in thicknefs, and the fubftance of thefe lines or cir- .c3cs is very hard arid firm, but the fubftance of the We&d,

which lies between, and unites thefe to each ether, is much lefs fo. This intermediate matter is always the weak part of the Wood, and its ftructurc and organization is perfectly dif- ferent from that of the woody cones, and depends entirely on the manner in which thofe cones are united to one another. This is thus explained :

The veflels, which are longitudinally difpofed in the Wood* and convey the nouiifhment to the button, not only are ex- tended and hardened by the action of the fap in motion, and by the firm particles it depofits ; but they are ever attempting alfo an extenfion of another kind ; they are ramified all along ■ as they go, and break into numberlefs extremely minute fila- ments, which ill'ue from them like lo many branches ; thefe, on the one part, are deftincd to the production of the bark of the tree ; and on the other, are connected to the Wood of the preceding year, and form between the two woody beds a fort of fpungy reticular work, which, when cut tranfverfely, even to a great thicknefs, mews numberlefs little cavities and holes, refembling a fort of lace-work. The woody beds are therefore united to one another by a fort of net-work ; this net-work, however, does not occupy nearly the fpace of the woody cir- cles which it fi-parated, and is ufually indeed but about a fixth part of their thicknefs. This thicknefs is much the fame in all the trees of the fame fpecies, whereas the ivoody beds vary in them very confiderably in thicknefs ; in the oak they are found from a fixth to a four and twentieth part of an inch in thicknefs.

By this e-eSy expofition of the texture of Wood, it Is eafy to> difcover that the longitudinal coherence of the particles of it muft needs be vaftly greater than the tranfverfe :■ one fees alfo that, in little pieces of Wood, as in a bar of an inch thicknefs, if there are fourteen or fifteen of thefe ivoody beds, there will alfo be thirteen or fourteen of thefe intermediate fpaces; and confequently it will be much weaker than if there were but five or fix of thefe woody beds in it, and confequently but four or five of thefe intermediate fpaces.

It may alfo be obferved, that in thofe little bars of Wood there are two or three of the woody beds wounded, which is often the cafe ; the ftrength of the bar muft be thence greatly im- paired : but the greateft fault thefe fmall pieces of Wood are fubject to, is the different difpofition of thefe beds in the dif- ferent parts of the fame tree; and' this difference is fo great, that the force or ftrength of a large beam of any Wood, cannot be computed by proportion, from that of a fmall piece of the fame Wood ; which,' were it poflible, would make calcula- tions of this kind extremely eafy. The ingenious author of this paper has from hence calculated the force and ftrength of timber ufed in building. Memoirs Acad. Par. 1740. See the article Timber.

All kinds of Wood are to be preferved from the worm, and from many other occafions of decay, by oily fubftances, par- ticularly the effential oils of vegetables. Oil of fpike is excel- lent, and oil of juniper, turpentine, or any other of this kind, will ferve the purpofe ; thefe will preferve tables, inftruments, €3V. from being eaten to pieces by thefe vermin, and linfeed oil will ferve, in many cafes, to the fame purpofe ; probably nut-oil will do alfo, and this is a fweeter oil, and a better varnifh for Wood. Mortimer's Hufbandy, vol. 2. p. 105- See the article Timber.

Some of the Weft-Indian trees afford a fort of timber which, if it would anfwer in point of fize, would have great advanta- ges over any of the European Wood in fhip-building for the merchant-fervice, no worm ever touching this timber. The acajou, or tree which produces the cafhew-nut, is of this kind ; and there is a tree of Jamaica, known by the name of the white-wood, which has* exactly the fame property, and fo have many other of their trees. Phil. Tranf. N°. 36. To feafon Wood expeditiously for fea-fervice, it has been ufual to bake it in ovens. Boyle's Works abr. vol. 1. p. 135, The art of moulding Wood is mentioned by Mr. Boyle b as 2 defideratum in the art of carving. He fays, he had been cre- dibly informed of its having been practifed at the Hague; and fufpects that it might have been performed by fome menftruum that foftens the Wood, and afterwards allows it to harden again, in the manner that tortoife-fhell is moulded. Or, per- haps, by reducing the Wood inty a powder, and then uniting it into a mafs with ftrong but thin glue. And he adds, that, having mixed faw-duft with a fine glue made of ifing-glafs % flightly ftraining out what was fuperfluous through a piece of linnen, the remainder formed into a ball and dried, became fo hard as to rebound when thrown againft the floor. — [ b Works abridged, vol. r. p. 130. c See the article Glue.] The people who work much in Wood, and that about fmali works, find a very furprifmg difference in it, according to the different feafons at which the tree was cut down, and that not regularly the fame in regard to all fpecies, but different in re- gard to each. The button-mould-makers find that the Wood of the pear-tree, cut in fummer, works tougheft ; holly, on the contrary, works tougheft when cut in winter ; box is mellowed when it has been cut in fummer, but harder! when cut about Eafter ; hawthorn works mellow when cut about- October, and the fer vice is always tough if cut in fummer. Merrefs Notes on Neri, p. 263.

It is a very well known quality of metals, to be longer and larger

when