Page:Cyclopaedia, Chambers - Volume 1.djvu/721

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double its Chord : The Radius of the Evotute being The Gum we call Euphorbium, is form'd of the Juicd

double the fame; and the Evohlte of a Cycloid, being it of a Tree, or rather Plant, ^ of the fame Name, pretty

felf a Cycloid. See Rectification, Cycloid, iSc. frequent m Mauritania; tho' the Species of the Tree, or

Monf. Varignon has applied the Doctrine of the Radius Plant, has been greatly controverted. The Generality of

of the Evohlte to that of Central Forces; fo that hav- our latetl Botanifts, make it a ferulaceous Plant; and Mr.

ing the Radius of the Evolute of any Curve; one may Profeffor Hermanmis calls it the Tithymalus Mauritanus

have the Value of the Central Fotce of a Body which Aphyftos Angulofus tS Spinofus. Hort. Acad. Lug. Ba-

moving in that Curve, is found in the fame Point where tav. 598. 9

that Ray terminates : Or reciprocally, having the Cen- It has no Leaves; but in Lieu thereof puts forth along

tral Force given, the Radius of the Evohlte may be de- its Stem a Kind of lone prickly Eyes, or Buds. Which

Buds, it is, that yield that gummy Juice, call'd Euphor- bium Officinarum. 1

Some Authors will have it, that the Gum is drawn from

termined. Hijl. de I' Acad. Roy. des Sciences. An. 1706. Imperfetl E volute. Monf. Reaumur has given a new Kind of Evohlte under this Denomination. Hitherto, the

Mathematicians had only confider'd the Perpendiculars let the Plant by Incifion; others, on the contrary, fay it. oozes

fall on the Points of the Convex Side of the Curve : If fpontancouily : The Juice, we are told, is fo very fubtile,

other Lines, not perpendicular, were drawn upon the and penetrating, that the Perfon who taps the Tree, is

fame Points, provided they were all drawn under the fame forced to ftand at a good Diftance, and make the Incifion

Angle, the Effect would be the fame; that is, the ob- with a long Pike; otherways it gets to the Brain, and

lique Lines would all interfect within the Curve, and by occafions dangerous Inflammations. It oozes out in great

their Intel fections, form the infinitely fmall Sides of a new Curve, whereof they would be fo many Tangents.

This Curve would be a Sort of Epicycloid, and would have its Radii; but, an imperfect one, fince the Radii are not perpendicular to the firft Curve. Hijl. de I'Acad. &c. An. 1709.

EVOLUTION, in Geometry, the unfolding, or open- ing, of a Curve, and making it defcribe an Evohlte.

For the Nature of Evolution. See Evoluta.

The Equable Evolution of the Periphery of a Circle, or other Curve, is fuch a gradual Approach of the Circum- ference to Reffcitude, as that all its Parts do meet toge- ther, and equally evolve, or unbend; fo that the fame Line becomes fucceflively a lefs Arc, of a reciprocally greater Circle, till at laft they change into a ftraight Line. In Philof. TrmfdQ. N°. 260. a new Quadratrix to the the Circle, is found by this Means, being the Curve de- scribed by the equable Evolution of its Periphery.

Evolution is alfo ufed for the Extraction of Roots out of Powers, in which Senfe it is directly contrary to involution. See Extraction.

Evolution, in the Art of War, is a Term applied to the divers Figures, Turns, and Motions, made by a Body of Soldiers, in ranging them in Form of Battle, or in

Abundance, and is gather'd in a Sheep's Skin, wrapp'd round the Tree.

'Pliny tells us, that the firft Difcovery of Euphorbium is attributed to Juba King of Lybia, who denominated it from Euphorbius his Phyfician, Brother of Mufa, Phy- fician to Allgujlus.

Etmuller affures us, that the Plant, which yielded the Euphorbium of the Antients, is now unknown to us; but if we go by "Pliny's Defcription, the Plant call'd Schadidd Calli in the Hortus Malabaricus, muft be the antient Euphorbium. This Difcovery is owing to Commehnus, Bourguemaifter of Amjlerdam, and Profeffor of Botany.

EUPHORT, fignifies the fame as Euchrafy. See

EuCHRASY.

EUPSYCHIANS. See Eunomioeupsychians.

EURIPUS, in Hydrography : The Word, originally and properly, fignifies a certain Streight of the Sea, between Btstia, and the Negropom; where the Currents are fo ftrong, that the Sea is faki to Ebb and flow feren Times a Day; in which Place, as the Story commonly goes, Arifiotle drown'd him felf, out of Chagrin, for not being able to account for fo unufual a Motion.

But Euripus has fince become a general Name for all Stteights, where the Water is in great Motion and Agi-

thanging their Form; either in the Way of Exercife, or tation.

when in aftual Engagement. The antient Circus's had their Euripi, which were no

'Tis by the Evolutions, that the Form, and Pofture of other than Pits, or Ditches, on each Side the Courfe; into

a Batallion, Squadron, &c. are changed 5 either to make which it was very dangerous falling with their Horics and

good the Ground they are upon, or to poffefs themfelves Chariots, as they run their Races.

of another, that they may attack the Enemy, or receive an The Term was alfo applied by the Romans, m Parti-

Onfet more advantageoufly. cular, to three Canals, or Ditches, which encompalled the

The Military Evolutions, are Converflons, Counter- Circus on three Sides; and which were fill'd occafionally,

marches, or Wheelings, ^Doublings of Rank or File, ££c. to reprefent Nanmachia, or Sea Battles.

See Conversion, &c. The fame People call'd their fmalleft Fountains, or

ta.Hofce, a Jefuite in 1597, printed a Treatife of Naval Jets d' Eau, Canals in their Gardens, Euripus' s; and

Evolutions, in Folio : — By Naval Evolutions, he means their largeft, as Cafcades, £fc. Niles.

the Motions made by a Fleet, Squadron, or Naval Ar- mament, in order to put themfelves into a proper Ar- rangement, or Situation, for attacking the Enemy, or defending themfelves with the moft Advantage.

The Word is Latin, Evolatio, form'd of the Prepofition e out, and volvo, I roll or wind, q. d. an umvinding, or unrolling.

EUPHONY, Euphonia, in Grammar, an Eafinefs, Smoothnefs, and Elegancy of Pronunciation. See Pro- nunciation.

The Word is Greek, form'd of *v, bene, well 5 and ^iafiij Vox, Voice.

Ghiintilian calls the Euphonia, Vocalitas; Scaliger, facilis pronumiatio.

The Euphonia is properly a Kind of Figure, whereby we fupprefs a too harih Letter, or convert it into a fmoother,

The Word is derived from the Greek, su, facile, eafily, and uTTt

EURYTHMX, Eurythmia, in Architeflure, Painting, and Sculpture; a certain Majefly, Elegance, and Eafinefs appearing in the Compofition of divers Members, or Parts of a Body, Building, or Painting; and refulting from the fine Proportions thereof. See Proportion.

The Word is Greek, and fignifies literally a Confonance, or fine Agreement, or as we may call it, a Harmony of all the Parts; being compounded of ev, well, and p t/Sp.©-, Rythmus, a Cadence, or Agreement of Numbers, Sounds, or the like Things. See Rythmus.

Vitruvius ranks the Eurythmia among the effential

contrary to the otdinary Rules. There are Examples enough p am " f '"ArchYteflure : He defcribes It as confill-

in all Languages.;„„; n the B eauty of the Conftruction, or Affemblage of

EUPHORBIUM, or Euphorbia, in Pharmacy, a Kind (h ° feveral p arts ^ f (he Wor][) whkh rende| . its Afpecl, or

of Gum, brought from Africa, in little roundilh 1 leces, who]e A ance „ race f u l : F, gr. when the Height

whitiih when new, and yellowifh when old, very inarp corre f pon £ s t0 the Breadth, and the Breadth to the

to the Tafte, but void of Smell. See Gum.

The principal Ufe of Euphorbium, is external; being a great Ingredient in divers refolutive Plafters, as well as in Tinfture, and Powder for flopping of Gangrenes, cleanfing of foul Ulcers, and exfoliating carious Bones.

Internally ufed, 'tis a Purgative, but fo violent a one, that 'tis almoft out of Doors, as tearing off" the necc 'j faty Mucus or Covering of the Stomach and Bowels, and occasioning Dyfenteries. Yet we are told the Africans ufe it very commonly; tho' they firft quench its Fire in Purflain Water.

Its Powder is a violent Sternutatory, and to be ufed very cautioufly, and never alone, but mix'd with a fmall Quan

correfponds to Length, & e.

■ From thefe three Ideas, Cor "Defigns, viz. Orthography,

Sceno%raphy, and Profile) it is, that the fame Eurythmy, Majeftica, and Vemifta Species Edificii, does Relult; which creates that agreeable "— k

veral Dimenfions; fo as nothing feems ^proportionate, too long for this, or too broad fit that, but correfponds - jull and regular Symmetry, and Confent of all the with the whole.' Evelyn's Account of Arcbft. &c

' Parts

See Symmetry,

EUSEBIANS, a Denomination Arians, on Account of the Favour

cautiouuy, ana never alone, but mix a witn a una" ^«- - - ::• „.„ f r ^,r„ rea tity of fome other Powder,' to guard againft its intolerable ^"^fe siJUi

Heat.

given to the Sect of

id Countenance, which

i Ihew'd, and procured for them

AN5 > „ -

EUSTA-