The Revocation of an Offer after it is accepted of, is invalid. — All preceding Wills or Teftaments are revoked by the laiti— A Prior Qauftral is revocable at Pleafure.— The Revocation of the Edict of Nants was fatal to the Vrench Proteftants. See Edict-
REVOLT. See Rebellion.
REVOLUTION, in Politicks, is a grand Turn or Change of Government.
There are no States in the World but have undergone frequent Revolutions.— -The Abbot de Vertot has furnifh'd us with two or three good Hiftories, of the Revolutions of Sweden, the Revolu- tions of Rome, &c.
The Revolution, is ufed by Way of Eminence, for the great Turn of Affairs in England vn 16889 when King Jams II. ab- dicating, the Prince and Princets of Orange were declared King and Queen of England, &c. See Abdication.
The Word is form'd from the Latin, re-voho, to roll back- wards.
Revolution, in Geometry. The Motion of any Figure quite round a fix'd Line, as an Axis, is called the Revolution of that Figure; and the Figure fo moving is faid to Revolve. See Axis.
Thus a right angled Triangle revolving round one of its Legs, as an Axis, generates by that Revolution, a Cone. See Cone. ,
Revolution, in Aftronomy, is the Period of a Star, Planet, Comet, or other Phenomenon ; or its Courfe from any Point of its Orbit, till it return to the fame. See Planet, Period, &c.
The Planets have a twofold Revolution ; the one about their own Axis, ufually called their Diurnal Rotation, which conftitutes what we call their Day. See Diurnal and Day.
The other about the Sun, called their Annual Revolution, or Period; constituting their Tear. See Annual and Year.
Saturn, according to Kepler, makes his annual Revolution in the Space of 29 Years, 174 Days, 4 Hours, 58′ 25″ 30′′′. Jupiter in 11 Years, 317 Days, 14 Hours, 49' 31" 56"' Mars 1 Year, 321 Days, 23 Hours, 31' 56^ 49'"- Venus in iz^Dsys, 17 Hours, 41-' 55" 14/". Mercury in 87 Days, 23 Hours, 14' 24". See Saturn, Jupiter, Mars, &c.
REVULSION, in Medicine, the turning of a violent Flux of Humours, from one Part of the Body to another, either neighbouring or oppofite, Part. See Humour, Derivation, &c.
In very dangerous Wounds, where the lo(s of Blood is great, and the flopping it fpeedily enough, impracticable ; 'tis ufual to open a Vein in fome remote Part, to caufe a Revulfon ; that is, to turn the Courfe of the Blood from the former Part. See Phlebotomy.
Kevulfions are alfo caufed by Cupping, Friction, &c. See Cupping and Friction.
The Term Revulfon is alfo ufed for a great Turn or Rcvulfion of Humours in the Body. — Sudden Dileafes are occafioned by great Revulfons of Humours, which fall all at once on certain Parts.
RHABDOIDES, [jin Anatomy, a Name given the fecond true Suture of the Skull ; calPd alfo the Sagettal Suture. See Suture.
The Word is form'd from the Greek, jd$®*, Rod, or Staff, and«^3>", form.
RHABDOLOGY, in Arithmetic!*, a Name fometimes given to the Method of performing the two moll: difficult and operofe Rules, viz, Multiplication and Divilion, by the two eafieft, viz. Addition and Subtraction; by means of two little Rods or La- minse, whereon are inferibed the fimple Numbers, and which are to be fhifted according to certain Rules.
Thefe Rods are what we popularly call Neper Bones, from their Inventor, a Scotijb Baron, who likewife invented Loga- rithms.
For their Defcriprion and Ufc, fee Nepairs-Bokw.
RHABDOMANCY, an antient Method of Divination, per- form'd by means of Rods, or Staves ; whence its Name, from the Greek $&$&>, Rod, and pdvtet*, Divination. See Divi- nation.
&t.Jerom makes mention of this Kind of Divination, in his Com- mentary on Hofeah, Chap. iv. 12. where the Prophet fays in the Name of God, My People ask Council at their Stocks; and their Staff declareth unto them: Which Pafiage that Father underftands of the Grecian Rhabdowancy.
The fame he finds over again in Ezekiel xxi. 2,1, 22. where the Prophet fays, For the King of Babylon food at the parting of the Way, at the Headof the two Ways, to ufe Divination ; he made his Arrows bright : Or as St. Jsrom renders it, he mixd his Ar- rows, he confuted with Images, he looked in the Liver.
If it be the fame Ki;id of Divination that is mentioned in the two Parages; Rhabdomancy iruft have been the fame Super- ftition im Bebmancy. See Belomancy.
In eflWfc che two are ordinarily confounded. — The Seventy themfclves Tranllate the C2WI of Ezekiel by faifi&r, a Rod ; though in ftriftnefs it iignify Arrows.
This, however, is certain, the Inftruments of Divination men- tioned by H-jfi.-.h, are different from thofe of Ezekiel. I n the former, 'tis nXJf, etfi, \*7pQ* makk,bis Wood, his Staff; In the
latter D1SD, hhitfin, Arrows. Though 'tis pofiible t£ey might uie Rods or Arrows indifferently; the military Men Arrows., and the reft: Rods.
It appears by the Laws of the Frifones, that the antient Inhabi- tants of Germany practiced Rhabdomancy. — The Scythians were likewife acquainted with the ufe hereof ; and Herodotus obferve?, ■ lib. iv. That the Women among the Alani fought and garnered together fineitraight Rods or Wands, and ufed them in the like Superftition.
RH AGADES, in Medicine, a Greek Term ufed for the Chaps or Clefts in the Lips. Sec Lips.
Rhagades, are alio a fort of little chap'd Ulcers of the Oe- dematous Kind; form'd of a iliarp, faline Humour, and occaf]. oning a' great Contraction, and itreightenicg of the Part, which is by this means fluivell'd up like a wet Parchment when held to the Fire. See Oedematous.
They arifc chiefly on the Fundament, the Neck of the Womb, the Prepurium, and even the Mouth; in which laft Cafe the Pa- tient is not able to (peak, chew, or the like.
They are fometimes moift, and of a cancerous Nature, eating deep, and difficult of Cure; but are more commonly of a leis malignant tendency, being the Conieqnences of a Diarrhoea, Dy- fenterys or the like. See Tumor, Ulcer, &c.
RHAGOIDE3, in Anatomy, the fecond Coat, or Tunic of the Eye; more ufually calfd the Uvea. See Uvea.
It has its Name Rhagoid's as refembling a Grape-ftone.
In this is the Hole calPd the Pupil. See Pupil.
RHAPONTICUM, a medicinal Root, in form re- fembling Rhubarb ; and nearly of the fame Virtues. — 'Tis frequently mix'd with Rhubarb by thofe who fend that Drug into Europe : They are df&ngutffi'd by this, that the Rhubarb is ufually in roundiih Pieces, the internal Stresks or Lines whereof run tranfverfe : And Rhaponticum in longifh Pieces, having its Streaks running length-wife. — Belides, that Rhaponticum chew'd inv the Mouth, leaves a Vifcidiry behind it, which Rhubarb does not. See Rhubarb.
The fcarcity of the Rhaponticum of the Levant, occafions the Mountain Rhaponticum, or Monk's Rhubarb, to be frequently fub- ftituted for it, which is a wild H\po\apatbum.~ -They are diftin- guifh'd by this, that the former is yellow without, and reddifh within; but the latter blackifh without and yellow within.
Dr. ^uincy, however, confounds the two, when he fays, the Rhaponticum grows plentifully in England; and that 'tis only u- fed as an Alterative, and does not come up to a Cathartic.
'Tis certain, what now obtains in the Shops, under the Name of Rhaponticum, is no other than the Mountain Rbapontic, or Monk's Rhubarb,- and is much inferior in Virtue to the Rhapon- ticum Verum.
The Rhaponticum was thus call'd, 5-. d. Root diPontus; be- caufe chiefly produced in the Country of Pontus, in Afa.
RHAPSODI, Rhapsodists, in Antiquity, Perfona who made a Bufinefs of finging Pieces of Homer's Poems.
Cuper informs us, that the Rhapfodj were cloath'd in red when they fung the Iliad ; and in blue when they fung the Odyflee.
They p-rform'd on the Theatres ; and iometimes for Prizes, in Contefts of Poetry, Singing, <&c.
After the two Amagonifts had finiOied their Parts, the two Pieces, or Papers they were wrote in, were joined together again* whence the Name, viz. from p'wiw, fio, I join together; and ah, Ode, Song.
But there muit have been other Rhapfidi of more Antiquity than thefe; People who compoled Heroic Poems, or Pieces in Praifeof Heroes and Great Men, and fung their own Compositions from Town to Town for a Livelihood: Of which PrOfeffioa was Homer himfelf.
Hence, fome Criticks inifead of the former Derivation, fetch Rhapfodif from p'a^&AAjw, to fmg with a Lawrel Rod in the Hand, which it feems was the Badge of the Primitive Rhap- fodi. ' r
Philochorus, again, derives the Word from pV&rw u^ } to pro- cure Pieces of Poetry to be compofed, as if they were not the Au- thors of the Poems they fung. This Opinion, to which Scaliger inclines, reduces thefe Rhapfodi to the firft Kind.— In effect, 'tis probable that they were all of the fame Clafi, whatever Diftin- ction fome Authors may Imagine; and that their Bufinefs was to fing or rehearle Poems, either of their own, or other People's Compofition, as might belt ferve their Purpofe, the getting of a Penny. So that we don't apprehend it any Injury to them, to fee them on the Foot of our Ballad-fingers ; many of whom, no doubt, Pen their own Dicties. After Homer's Time, 'tis no won- der they confined themfelves altogether to his Pieces, for which the People had the utmofi; Veneration : Nor is it furprizing they fhould (erect Stages, &c. and Difputc the Point of Recitation in Fairs and Markets.
RHAPSODOMANCY, an antient Kind of Divination per- formed by pitching on a Paifage of a Poet at hazard, and reck- oning on it as a Prediction of what was to befall. See Divi- nation and Chance.
There were various Methods cf practicing Rhapfodomancy^. —Sometimes they wrote feveral Verfes or Sentences of a Poet, on fo many Pieces of Wood, Paper, or the like ; fho'ok them together in an Urn, and drew out one* which was accounted the Lot.
Sometimes
