Page:Cyclopaedia, Chambers - Volume 2.djvu/269

 NAT

(tfi8)

NAV

moves and a£ls in all Bodies, and gives them certain Pro- perties, and procures certain Effects. See Providence.

In this, which Mr. Boyle confiders as the molt ufual Senfe, Nat'ire is nothing elfe but God, ailing hinifelf, and according to certain Laws he himfelf has fix'd. See God.

This feems pretty agreeable to the Opinion of many of the Antients, who made Nature the God of the Univerfe, the To Ylttv, who prefides over, and governs all ; tho others own'd this an imaginary Being, and by Nature meant no more than the Qualities, or Vermes which God has given his Creatutes, and which their Poets and Orarors took occa- fion of perfonifying.

F ' .Malkbranch fays, the Nature fo much talk'd of in the Schools is fit for nothing but to lead us back to Idolatry ; the antient Heathens hereby understanding fomething, which, without being God, afts continually throughout the Univerfe. Thus the IdoXNature mull be an aflual Principle, which, with the concurrence of God, is the next and im- mediate Caufe of all the Changes which befall Matter. Which feems to fall in with the Opinion of the Anima Mundi i as if Nature were a Subftiture of God, or a collateral Caufe with God, or a middle Being between God and created Things. See Anima Mundi.

Ariflotle defines Nature, Fr'mcipium (i Caufa matas £■> ejus hi quo eil prima per fe £S< non per accedens. A Definition foobfeure, that none of his Commentators, with all their Glofles, have been able to render it intelligible.

This Principle, which the Ferif utetics call'd Nature, they fuppofed to aft neceflarily ; and was therefore deftitute of Knowledge or Liberty. See Necessity.

Thus alfo the Stoics conceived Nature as a certain' Spirit or Virtue diffufed throughout the Univerfe, which gave - every thing its Motion, fo that all muff be dragg'd away by the invariable Order of a blind Nature, and an inevi- table Neceffity. See Fate.

In fpeaking of the Action of .Nature, no more is to be underltood, but that Bodies aB on one another, in a manner agreeable to the general Laws of Motion which the Creator has eHahlifhed.

In this lies the Myflery of that great Word, which is only a compendious way ofexprefling the Action of all Bodies : But the Mechanifm of Bodies,vioa\d, perhaps, better exprefs what is here meant by Nature. See Mechanism.

Some, Mr. Boyle obferves, will have rhe Nature of a thing to be only the Law that it receives from the Creator, and according to which it a£ls on all Occafions. But this is an improper, and figurative Expreflion.

The fame Author propofes a Notion of Nature as more fit than any yet given to pafs for the principal one of Na- ture ; with regard to which many Axioms and Expreffions relating to that Word, may be conveniently underflood. In order to this, he diftinguifhes between General and Par- ticular Nature.

General Nature be defines the Aggregate of the Bodies that make up the World in its prefent State, confider'd as a Principle by virtue whereof they aft and fuffer according to the Laws of Motion prefcribed by the Author of things.

Particular Nature of any Subordinate or Individual confifts in the general Nature apply'd to a diftinct Portion of the Uni- verfe. Or it is a Convention of the Mechanical Properties (as Magnitude, Figure, Order, Situation, and Local Mo- tion) of Parts convenient and fufficient to conllitute of, or entitle to, its particular Species or Denominations, the par- ticular Body they make up ; the Concourfe of all thefe being confider'd as the Principle of Motion, Reft, iyc.

Laws of Nature, are Axioms, or generalLaws, and Rules of Motion, and Reft obferved by natutal Bodies in their Actions on one another ; and in all the Changes which befall them in their Natural State. See Law.

The Laws of Nature, and of Motion, are, ineffecl, the fame; Cultom, indeed, has made fome difference, and we find Authors call the particular Cafes of Motion, Laws of Motion i which fee under Motion 5 the more General, or Catholic ones, and thofe from which, as from Axioms, the others are deduced, they call Laws of Nature.

Of thefe, Sir Ifaac Newton has eftablifhed three.

Laws of Nature.

i. Every Body perfeveres in the fame State, either of Reft, or uniform reRilinear Motion; except fo far as it is forced to change that State by fome foreign Force.

Thus Projectiles perfevere in their Motions, except fo far as they are retarded by the Refiftance of the Air, and the Caufe of Gravity ; and thus a Top, whofe Parts by their Cohefion, are continually drawing one another out of their rectilinear Motion, only ceafes to run round be- caufe refilled by the Air, and the Friclion of the Plane whereon it moves. And thus the larger Bodies of the Planets and Comets prefcrve their progreflive and circular Motions a long time undiminifhed in Regions void of all

fenfible Refiftance. See Vis Inertia, Resistance, and Medium.

2. The Change of Motion is ever proportional to the movin? Force whereby it is effeFled, and in the Direction of the Ki"ht Line wherein that Force is imprejYd.

If a certain Force produce a certain Motion ; a double Force will produce double the Motion ; a triple Fotce triple the Motion, whether it be imprefs'd all at once, or fuccefiively, and by degrees. And this Motion (fince it i s ever directed to the fame Point with the genetating Force) if the Body were in Motion before, is either to be added to it, as if the Motions confpire ; or fubftracted from it, as where contrary ; or added obliquely, as where oblique ; and is compounded with it, according to the Determinations of each.

3. Reaction is always contrary and equal to Aclion; or the Allions of two Bodies upon one another are always mutually equal, and directed contrary ways.

Whatever preffes, or pulls another, is equally prefs'd or pull'd thereby. Thus, if I prefs a Stone with my Finger, the Finger is equally prefs'd by the Stone. If a Horfe drawaXVeight by a Rope, the Horfe is equally drawn back towards the Weight; for the Rope being equally flretch'd each way, will with an equal Endeavour to relax itfelf, drive the Horfe towatd the Stone, and the Stone towards the Horfe, and will hinder the Progrefs of the one, as much as it promotes that of the other.

Again, if any Body by ftriking on another, do in any manner change its Motion, it will, itfelf, by means of the other, undergo an equal Change in its own Motion, by reafon of the Equality of the Preflure.

In thefe Aftions the Changes are equal ; not thofe, we mean, of the Velocities, but thofe ot the Motions, the Bodies being fuppofed free of any other Impediments. Foe the Changes of Velocities,which are likewife made contrary ways, in as much as the Motions are equally changed, are reciprocally proportional to the Bodies. See Reaction.

This Law alfo obtains in Attractions. See Attrac- tion.

Nature, in Profody : A Syllable is faid to be long or Jhorr by Nature, tofignify that it is fo without any Rule of Grammar, to render it fo by Pofirion, or otherwife.

NAVAL, fomerhing relating to Ships, or Navigation. See Ship and Navigation.

In this fenfewe fometimes fay, Naval Strength, a Naval Combat, &c.

Naval Crown, Corona Nivalis, among the antient Romans, a Crown adorn'd with Figures of Prows of Ships, confer'd on Perfons who in Sea-Engagements firft boarded the Ene- my's Veffel. See Crown.

Tho A. Gellius feems to fpeak generally, where he fays, the Naval Crown was adorn'd with Prows of Ships ; Lipfius diftinguifhes two kinds of Naval Crowns : The one he calls Simple, the other Rojlrata.

The firft he fuppofes plain, and given to the common Soldiers, &c. The latter much more Glorious, adorn'd with Prows of Ships, and only given to Generals, or Admirals, who had gain'd fome important Viclory at Sea.

NAVE, in Architecture, Navis Ecclefiie, the Body of a Church ; or the Place where the People are difpofed ; reaching from the Rail or Balluffer of the Choir to the chief Door. The Antient Greeks call'd it Tronaos. See Church.

The Nave of a Church belongs to the Parifiiionets ; 'tis they are to repair it, $$c.

Baldus derives the Word from the Greek »««5, Temple; which Salmafius brings from rm s, va-& v Ship ; by reafon the Vault or Roof of a Church bears refemblance to a Ship.

NAVEL, a Part in the middle of the Belly, by Anato- mills call'd Umbilicus. See Umbilicus.

NAVEL-Ariwg, by Anatomiftsis call'd FuniculusUmbilicalis. See Funiculus.

NAVICULARE Os, in Anatomy, the third Bone in the Foot, between the Aftragalus, and the OJfa Cuneifdrmia, thus call'd from Navis, a Ship, to which it bears fome Refem- blance ; for which reafon likewife it is fometimes call'd Cymbiforme, from Cymba, a Boat, and Scaphoides, from a Greek Word of the like import. See Foot.

It has behind it a large Sinus, which receives the fore convex Head of the firft Bone, and before it, is convex ; 'tis diftinguifhed into three Heads, which are received into the Sinus's of the Offa Cuneiformia.

NAVIGATION, the Art, or A£t of Sailing ; or of conducing a Veflel from one Place to another, thefafeft and moft commodious way.

This Art, in the full Latitude of the Word, comprehends rhree parts ; vis. F'irft, the Art of conftructing and building Ships, (fee Ship.) Second, the loading of Ships, (fee Burden.) And, Third, the Direction and Government

of