Page:Cyclopaedia, Chambers - Volume 2.djvu/986

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that it was the Cuflom of the Egyptians to put all the Books they compos'd under the Name of Trifmegiftus.

The Word had its rife k volvendo ; the antient way of making up Books being in Rolls of Bark, or Parchment. See Roll.

This manner lafted till Cicero's Time, and long after that Paper was invented, and Books wrote thereon— The feveral Sheets were glued, or pafted End to End, wrote only on one fide ; and at the bottom a Stick faflen'd, call'd Umbilicus ; and at the other end a piece of Parchment, whereon was the Title of the Book in Letters of Gold.

And yet, we are affuted, King Attilus had, long before, done up fome of his Books in the fquare form ; as having found the Secret of Parchment, which would bear writing on both fides. See Parchment.

At prefent, Volume is chiefly ufed in the fame Senfe with Some, for a Part or Divifion of a Work, bound feparately.

In this Senfe, we fay, the Councils arc printed at the

Louvre in 37 Volumes. See Tome.

T"be Volume of a Body, is fometimes alfo ufed among Philosophers, for its BuikfOC the Space inclofed within its Su- perficies.

VOLT, in the Manage, fignifies a round or circular Mo- tion, confifting of a Gate of two Treads, made by an Horfe going fideways round a Centre ; the two Treads marking parallel Tracks, one by the Fore feet, larger ; and the other by the Hind-feet, fmaller : the Shoulder, bearing outwards, and the Croup approaching towards the Centre.

2)s»2i-Volt, is a Round of one Tread, or two, made by the Horfe at one of the Angles or Corners of the Volt, or at the End of the Line of the PaCfade ; fo as when he is near the End of this Line, or near one of the Corners of the Volt, he changes Hands, to return by a Semicircle.

A Renverfed Volt, is a Track of two Treads, which the Horfe makes with his Head to the Centre, and his Croup out ; going fideways upon a Walk, Trot, or Gallop, and tra- cing out a larger Circumference with his Shoulders, and a fmaller with his Croup.

VOLUMUS, in Law, the firft Word of a Claufe in the King's Writs of Protection, and Lettets Patent. See Pro- tection.

VOLUNT, in Law, is when the Tenant holds Lands, $S>c. at the Will of the Leffor, or Lord of the Manor. See Tenant, Vassal, &c.

VOLUNTARY, in the Schools— The generality of Phi- lofophers ufe Voluntary in the fame Senfe with Spontaneous; and apply it to any thing arifing from an internal Principle, attended with a due Knowledge thereof— In which Senfe,' they fay, a Dog moves Voluntarily when he runs to the Pot! See Spontaneous.

Ariftotle and his Followers, reftrain the Term Voluntary to thofe Aflions that proceed from an inward Principle which knows all the Circumftances of the Action.

There are two Things, therefore requir'd to the Volunta- riness of an Action ; The firft, that it proceed from an in- ward Principle ; thus, walking for pleafure-fake is a Volun- tary Aftion ; as arifing from the Will commanding, and the moving Faculty obeying, which are both internal.— On the conttary, the Motion of a Man drag'd to Prifon is not Vo- luntary.

The fecond, that the Action be pcrform'd with a perfect Intelligence of the End, and Circumftances thereof: In which Senfe, the Actions of Brutes, Children, fleeping Peo- ple, (Sc, are not properly Voluntary. See Will.

Anatomifts diftinguifh between the Voluntary, and Natu- ral, or Involuntary Motions in the Body : Of the firft Kind are thofe of the Heart, Lungs, Pulfe, EjJc. See Muscular Motion.

VOLUTE, Voluta, in Architeflure, a kind of Scrowl, or fpiral Contortion, ufed in the Ionic and Compofite Capi- tals ; whereof it is the principal Charafter and Ornament. See Capital.

Some call it the Ram's-Horn, from its Figure, which bears a near refemblance thereto.

Moll Architects fuppofe, that the Antients intended it to reprefent the Bark or Rind of a Tree, laid under the Abacus, and twilled thus at each Extreme where it is at Liberty : Othets will have it a fort of Pillow, or Bolder laid between the Abacus and Echinus, to prevent the latter being broke by the Weight of the former, and the Entablature over it; and accordingly call it Tulvinus.

Othets, after Vitruvius, will have it to reprefent the Cutis or Treffes of a Woman's Hair. See Ionic Order.

There are alfo eight angular Volutes in the Corinthian Capi- tal, accompany'd with eight other fmaller ones, called Helices.

There are feveral Diversities in the Volute. — In fome, the Lift or Edge, throughout all the Circumvolutions, is in the fame Line, or Plane : fuch are the antique Ionic Volutes, and thofe of Vignola. — In others, the Spires or Circumvolutions fall back ; in others project, or ftand out. — Again, in fome the Circumvolutions are oval ; in others, the Canal of one Circumvolution is detach'd from the Lift of another, by a Vacuity or Aperture. — In others, the Round is parallel to the

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Abacus, and fprings out from behind the Flower thereof — In others, it feems to fpring out of the Vafe, from behind the Oram, and rifes to the Abacus, as in moll of the fine Com- pofite Capitals.

Confoles, Modillions, and other forts of Ornaments, have hkewife their Volutes. See Console, iic

The Volute is a Part of great Imporance to the Beauty of the Column. — Hence Architects have invented divers ways

of delineating it. The principal are that of Vitruvius,

which was long loft, and at laft reftor'd by Gouldman ; and that of falladio. — 'Daviler prefers the former as the eafier. — The manner thereof is as follows.

Divide the Altitude A B, (Tab. Arcbitetl. Fig. 12. Volute) into eight equal Parts, and affuming the Fifth QJ\ for a Diameter, from the Centre G, with half the Diameter GP, defcribe a Circle for the Eye of the Volute: — Biflect the Radii GPand GQ_in 1 and 4, and fubdivide the half Patts Gi andG4 each into three equal Parrs : Then, upon the right Line 1 4, conftruct a Square 1, 2, 3, 4 5 one of whofe Sides z, 3, continue on to D $ another 3, 4, to E $ and the third 1, 2, to C. From G dtaw right Lines, G z and G 3 ; which divide into three equal Parts. — Then, thro' 6 and 10, draw 6 L and 10 N, parallel to 2 D. And thro' 11 and 7 draw 11 O and 7 K, parallel to 3 E ; and thro'

5 and draw 5 H, and 9M, parallel to 1 C. Laftly,

from 12, 11, 10, 9, 8, e?e. ftrike the Quadrants PO, ON, NM, ML, LK, tfc. which will form the Volute.

VOLVULUS, in Medicine, a Latin Name, which fome Authors have given to a Difeafe otherwife call'd the Iliac Vaffion; and by others the Mijerere mei. See Iliac Pas- sion, ££?c.

'Tis a kind of Cholic, wherein the Patient voids his Ex- crements by rhe Mouth, inflead of the Anus ; by reafon the Membtanes of the Interline Ileon are drawn within one another, and form Knots, which prevent the ordinary Courfe of the Fieces. See Cholic.

VOMER, in Anatomy, a Latin Name, Signifying, lite- rally, a 'Ploughjhare ; ufed by Authors to denote the ele- venth Bone of the upper Jaw : by reafon of rhe Refemblance it bears to that Utenfil. See Maxilla.

The Vomer, or Vomer Aratri, is a thin Bone, placed in the middle of the Nofe, over the Palate, ferving to part the two Noftrils from each other. See Nostril.

'Tis fmall, but hard, and is join'd to the Spbenoides and Etbmoides, which have each of them little Eminences that are received into the Cavities of the Vomer ; by which means it is faflen'd in its Place. See Nose.

VOMICA, in Medicine, a Collection of Pus in any Part of the Body. See Pus.

When this Mafs or Collection is in the Lungs, 'tis called Vomica 'Pulmonum — When in the Kidneys, Vomica Renum, Ike. See Lungs.

The Vomica of the Lungs differs from an Empyema, which is a Collection of Pus in the Cavity of the Thorax. See Em- pyema.

Nux Vomica, Vomiting Nut, is a little round, flat, woolly Fruit, half the bignefs of a Farthing ; hard as Horn, of a Mouie-colour without, but of various Colours within : fometimes yellow, fometimes white, and fometimes brown.

'Tis not known what the Plant is that bears it. — 'Tis a Poifon for Dogs, and divers Quadrupeds, which it kills pre- fently, thro' exceflive Vomiting. See Poison.

VOMITING, Vomitus, the Act of calling up, or eva- cuating by the Mouth what is contain'd in the Stomach. See Evacuation.

This Aftion has been generally allow'd to be owing prin- cipally, to the Contraction of the Fibres of the Stomach, when irritated by the acrimonious Quality, or opprefs'd with the Quantity, of its Contents. See Stomach.

But M. Chirac, and after him M. du Vemey, and others, fet afide the Fibres of the Stomach ; and advance, That Vomiting is produced wholly by the extraordinary Motions of the Diaphragm, and the Mufcles of the lower Venter. — So that the Stomach is here fuppofed deftitute of all Aclion, and calls back its Contents only by its being com- ptefs'd and flatted, from fome foreign and accidental Caufes.

However, Boerhaave, and moll of our lateft Writets, al- low both the Stomach, the Diaphragm, and the Mufcles of' the Abdomen, to have their fhare in the Action of Vomi- ting : Accordingly, that excellent Author makes Vomiting to confift in a convulfive and retrograde Motion of the muf- cular Fibres of the Gullet, Stomach, and Intettines ; as well as thofe of the Abdomen, and the Septum I'ranfverfum 5 which, when in a lefs degree, produce a Naufea, and in a greater a Vomiting. See Nausea. '

By the Contraction of fo many Parts, the Stomach comes to be lqueez'd, as in a Prefs ; whence it is obliged to give up what is contain'd in its Cavity, and the neighbouring Parts ; juft as Water is in a Bladder or Sponge, when fqueez'd between the Hands.

The Evacuation, too, muft be upwards, rather than down- wards 5 by reafon the Paflage is more open and eafy that P P P p way,