Page:Cyclopaedia, Chambers - Volume 1.djvu/781

 FIR

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FIR

to flif an <* m ' x the > r Medicines therewith : The fifth, the little Finger, Aurioularis; by reafon the Ear is pick'd therewith.

Fingers "Breadth, a Meafure, of two Barley Corns in length, and four laid Side to Side. See Measure. PINING, fee Refining, Clarifying, SSc. FINISHING, in Architeaure, sSs. is frequently applied to a Crowning, Acroter, igc. rais'd over a piece of Building, 10 terminate, and finijh, or compleat it. See Crown- ing.

FINITE, fomething bounded, or limited; in Contradic- tion to Infinite. See Infinite.

The School-men make two kinds of Finite* : The one as to Extenfion; which is applied to Things that have not all poflible, or conceiveable Extenfion.

The other as to PerfeBion, applied to Things, which have not the laft Perfe&ion.

To get an Idea, e. gr. of a Thing finite in Point of Perfection, we firft conceive the thing as having certain Perfections; and then conceive fome other Perfection, which it has not, or fome Perfeflion in a further Degree. Thus, when I fay that Three is a finite Number, I firft conceive' a Number, confifting of three Unites 5 then con- ceive other Unites beyond thefe three. Thus it is I con- ceive my Mind finite, by obferving certain Perfections be- yond what I find in my Mind.

After the fame manner I conceive this Study to be fi- nite, by having an Idea of Extenfion beyond what is con- tained therein. See Extension.

FIN1TOR, in Aftronomy, the Horizon; thus called, by reafon it finijbes or bounds the Sight or Proipefl. See Ho- rizon. FIOL, fee Phiol.

FIRE, in Phyfiology. The moft univerfal and fenfible Character of Fire; and that which bell defines and diftin- guifhes it from every other thing, is its Heating.

Fire, therefore, may be defined to be whatever warms, or heats Bodies. See Heat.

Again, as Heat is fomething, whofe Prefence we beft perceive by the Dilatation of the Air or Spirit in the Ther- mometer : Fire may be defined to be that whofe Prefence we perceive by the Expanfion of the Air, or Spirit in the Thermometer. See Rarefaction.

Whence it follows, that Fire is a Body, and a Body in Motion.

Its Motion is argued from its expanding the Air; which is not effected without communicating Motion thereto : And its Corporeity is proved by Experiment. , For pure Mercury being inclofed in a Phial with a long Neck, and kept in a gentle Heat for the fpace of a Year, is reduced into a Solid; and its Weight confiderably in- creafed; which Increafe can arife from nothing but the Ac- ceflton of Fire. See Mercury*

'Tis a Difpute of fome Standing among Philofophers, Whether Fire be any fpecifick Subftance, originally diftinct from all other; or whether it be the Matter of other Bo- dies, only under certain peculiar Modifications, i. c. Whe- ther Fire be luch by its own Nature, or by Motion.

Fire, makes one of the vulgar, or Peri patetick Elements, defined to be hot, and dry; or, it is that Part, or Ingredient in all Bodies, which is hot in the higheft Degree, and dry in an inferior one. See Element.

. What the School-Philofophers add further, as to the Na- ture of Fire, is, that it is a Simple Body; as not including any Contrariety of Qualities; and a Body abfolutely light, as tending naturally upwards; For which reafon they hold its natural Place above all the other Elements, between the Extremity of our Atmofphere, and the Moon; and the Source of Fire fuppofed to refide in that Sphere, they call Elementary Fire. Se"e Elementary.

Fire, according to the Cartefians, is an Affemblage of the more folid, earthy Particles; which fwimming in the rapidly fluid Matter of the firft Element, become vehe- mently agitated thereby; and by this intenfe Agitation or Motion are difpofed to give the Senfation of Heat, Eight, &c. See Cartesianism.

Fire, according to Sir /. Newton, is a Body heated fo not, as to emit light copiouily.

For what elfe, fays that Philofopher, is red-hot Iron, but fire'. And what elfe is a. fiery Coal, than red hot Wood! % which he fuggefts, that Bodies which are not Fire, may be changed and converted into Fire. See Flame.

Fire, according to fome of the lateft Philofophers, is a certain Subftance, or Body fui generis, originally fuch; and not producible by any Motion or Alteration of other Bodies.

Thefe Authors lay it down as a very fubtile, moveable, penetrating Body; and the Caufe or Inftrument of Heat and Light. Some of them add, that when Fire enters the Eye in right Lines, it produces or excites the Idea of ■Light; which rectilinear Motion they account abfolutely neceOary to the Idea of Light. See Light.

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Whereas, to produce Heat, and the other Effects of Fire, iuch Motion is not required; but on the Contrary, an irre- gular, various Motion is fitter to produce the fame. See Heat.

The Nature of Fire is fo wonderful, and abftrufe; that the Anticnts generally revered it as a God : Among the Moderns, we can fcarce name one one Point in all Philofophy of more Importance, or lefs underllood. _ Fire, in EfRa, is the univerfal Inftrument of all the Mo- tion, and Aftion in the Univerfe : Without Fire, all Bodies would become immoveable; as in a fevere Winter we ac- tually fee our Fluids become folid, for want thereof. With- out tire, a Man would harden into a Statue; and the very Air cohere into a firm, rigid Mais.

Are, then, is the univerfal Caufe of all Mutation, or Change; f or all Mutation is by Motion; and all Motion by Fire.

_ Several Authors have labour'd to fet this grand Agent in its juft Light; and particularly the excellent Boerhavc, in a new Courfc of Experiments, and Lectures exprefiy on the Subjeft, 2)e Igne. That Author has indeed done Wonders : The Sum of his Doflrine we ihall here fub- join.

Fire, then, is diftinguifh'd into two Kinds; as it is in it felt; called Elementary; or as it is join'd with other Bo- dies, called Culinary Fire.

Pure, or Elemental Fire, is fuch as it exifts in it felf 5 which alone we properly call Fire.

■ Common, or Culinary Fire is that exifting in ignited Bo- dies; or excited, by the former, in combuftible Matters, the minute Particles whereof joining with thofe of the pure Fire, conftitute pure Flame.

This latter is improperly called Fire; in regrad only a fmall Part of it is real, or pure Fire.

Pure Fire, fuch as collected in a Burning Giafs, yields no' Flame, Smoak, Aftles, or the like : Confequently, in ignited Bodies, that which flames, fmoaks, e£fc. is not limply Fire.

The Effefts, Nature, Properties, &c. of each ihall be confider'd.

I. 'Pure, or Elemental Fire of it felf, is imperceptible 5 and only difcovers it felf by certain Eftefls, which it pro- duces in Bodies; which Effects are only learnt, by obferving the Changes that arife in thofe Bodies.

The Firft EffeB of Elemental Fire on Bodies, is Heat; which arifes wholly from Fire; and in fuch manner as that the Meafure of Heat is always the Meafure of Fire; and that of Fire, of Heat. So the Heat is infeparable from Fire. See Heat.

The Second is, Dilatation in all folid Bodies; and B.a- refaBion in all Fluids.

That both thefe are infeparable from Heat, is evident from numerous Experiments, An iron Rod, or Bar being heated, increafes in all its Dimenfions; and the more fo, as it is further and further heated : Upon expofing it to the Cold again, it contracts and returns fuccefllvely through all the Degrees of its Dilatation, till it arrive at its firltBulk 5 being never two Minutes fuccefllvely of the fame Magnitude.

The like is obferved in the heavieft of all Bodies, Gold; which, when fufed, takes up more Space than before : So Mercury, the heavieft of; all Fluids, we have known to af- cend in a narrow Tube over the Fire, to above go times' its Height. See Rarefaction, and Dilatation.

The Laws of this Expanfion, are i°. That the fame De- gree of Fire rarefies Fluids fooner, and in a greater Degree than it does Solids. Without this, the Thermometer would be of no ufe; fince the Cavity of the Tube would then be dilated in the fame Proportion, as the Fluid is rarified. z". The lighter the Liquid, the more it is di- lated by Fire. Thus Air, the lighteft of all Fluids, expands the moft; and after Air, Spirit of Wine. See Thermo- meter.

The Third EffeB of Fire on Bodies, is Motion : For Fire, in warming and dilating Bodies, mult of Necefftty move their Parts.

In Eftefi, all the Motion in Nature arifes from Fire alone; and taking this away, all Things become immoveable: Upon the Abfence of only a certain Degree of Fire, alt Oils, Fats, Waters, Wines, Ales, Spirits of Wine, Vege- tables, Animals, $$c. become hard, rigid, and inert: And the lefs the Degree of Fire, the fooner, and more violently is this Induration made.

Hence, if there were the greateft Degree of Cold, and all Fire were abfolutely taken away, all Nature would grow into one concrete Body, folid as Gold, and hard as Dia- mond. But upon the Application of Fire, it would reco- ver its former Mobility.

Confequently, every Diminution of Fire is attended with a proportionable Diminution of Motion : And vice verfa. See Cold.

This Fire, whofe Effects we have been relating, needs no Air, or Pabulum to fuftain or preferve it.

For