Page:Cyclopaedia, Chambers - Volume 1.djvu/774

 FIB

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FIE

Upon this View there arifes a very natural Explication of fcveral Terms, much ufed by mechanical Writers ; fuch as DiftraSion, Contraction, Vibration, Undulation, Tomck Motion, ConcuJJion, Relaxation, Corrugation, and Elaflicity of the Solids ; all which are but different ways of exprei- fing the various Modifications and Difpofitions of thofe Ma- chinula: with which all the Fibres are compofed.

Thus much being granted of the Contexture of a Fibre, and the Requisites for its Oilce, it is to be confider'd, how it comes firft to be fet in Motion, and by what Mechanifm it is afterwards carried on. Suppofe then the Fibre (Fig. 3 .) in fuch a State of DiftraSion, as before mentioned ; it is certain by Req. 2. that in all its Parts there is a Nifus rcfti- tuendi: Where, then, any external Impulfeis made againft it from R to S, fucceffively thrufling it from 2> towards <%, it is certain that againft 1 for inftance, the Thread will be more diitrafted, than in any other Part; and there- by will there be a greater Endeavour of Reftitution. And therefore the Impulfe parting on towards S, all the conftituent Machinuhe, 1, 2, 3, 4., will fucceffively move after one another.

To make this Matter ftill more plain, let a Portion of an Artery be reprefented by Fig. 4. through which the Blood is continually propelled in a Direction parallel to its Axis: Nothing is more certain, than that if it were not for the Refiftance of the Sides of the Artery at E F, the Blood fetting out at A, S, would go on by the prick'd Lines C, 2) ; and therefore it cannot but ftrike againft the Sides of the Artery at E, F, and diftracl: them there more, than any where elfe ; whereby their Endeavours of Refti? tution will be there the greateft : And therefore, when the Impulfe of the Blood has raifed them to a certain Mca- fure, wherein their Endeavours of Reftitution will exceed the Impuife which raifed or diffracted them, their con- tractile Powers will draw them again into the fame Dimen- sions ; and confequently the Blood will be thruft forward in- to the next Section of the Artery, and fo on fucceffively from one to another, thro' the whole Courfe of its Circu- lation ; the Contract ion of one Section of an Artery being the true Caufe of the Blood's Impulfe againft, and railing the next. See Circulation.

Fibre is alfo ufed in Phyficks, for long, fine Parts, or Threads, whereof other natural Bodies are compofed, and which prevent their being friable, or brittle. ments; which are Modifications of their woody Subftance, penetrating and terminating in the Parenchyma, or Pith. See Plant, Wood, S?c.
 * Trees, Plants, and Fruits have their Fibres, or Capilla-

In the common Ufe, Fibre is only applied to the flen- der, capillary Roots of Plants.

Kepler even gives Fibres to the Stars; and explains fe- veral of their Motions from the Situation of their Fibres.

FIBRILLA, a little Fibre, or Carillament. The Word is a Diminutive of Fibra. Each Fibre is divifible into a number of leffer Threads, called Fibrillie. See Fibr.e.

FIBULA, in Anatomy, one of the Bones of the Leg, called alfo 'Perone, Sura, and Focile minus. See Bone, Lec, Focil, £Sfc.

The Fibula is the outer, and flenderer of the two Bones of the Leg ; and yet, notwithstanding its being more ex- pofed, and its being much weaker than the inner Bone, or Tibia, 'tis not fo often broken, as being more pliant and flexible ; fo that the Tibia often breaks, leaving the Fi- bula entire.

The Fibula is join'd or articulated with the Tibia, at both Ends, by a kind of clofe Arthrodia.

It is divided into three Parts ; the upper, which is a round Head, which terminates a little below the Knee, and receives a lateral Protuberance of the Tibia into a fmall Si- nus ; by which the Articulation of this Part is effeaed : The Middle is very flender, long, and triangular, like the Tibia, but fomewhat more irregular. The lower Part is receiv'd into a Sinus of the Tibia, and then /hoots out in- to a large Procefs, called the Malleolus internus, or outer Ankle : It is a little hollow on the Infide, to give Liberty for the Aftragalus to move; and a little Convex on the Out-fide, that it may have the more Strength, to retain the Aftragalus.

The Tibia and Fibula only touch at the two Extremes like the Radius, and Ulna : The Space between them is' filled up with a ftrong membranous Ligament, which ties them together, and ttrengthens the Articulation. See Ti- e*a, ..

Fibula, Sutton, in Surgery, an Inftrument in ufe anions the Antients, for the doling of gaping Wounds.

Celftis fpeaks of the Fibula, as to be ufed when the Wound was fo patent as not eaiily to admit of beinw fewed.

Authors are fomewhat atalofs as to the Form of theFibute. Guido fays, they were made of iron Circles, or Semi-circles, bent backwards both ways; theHooks whereof being falten'd on both Sides to the Wound, anfwer'd exactly to each other : But, as this muft have been an infupportable Pain to the Patient, this Defcription is generally fet afide.

Fallopius, SanSorius, and others, take the Fibula to have been, in reality, no more than the fewing up of the Wound with a Needle and Thread, ufed at this Day. See Suture.

FIBULvEUS, in Anatomy, a Mufcle of the Leg, call'd alfo Peroneus primus. See Peroneus.

FICUS, a kind of Wart, or Excrefcence, yielding a very ftinking Sanies, arifing fometimes on Fractures of the Skull, but more ufually about the Fundament, and Puenda.

The Phyficians more ufually call it Sarcoma, oi .atl£> Flefh. See Sarcoma.

FICHANT, Figcns, a French Term, ufed in Fortifica- tion : Thus, a Flank Ficbant, or a Line of Defence Fichant ; is the Place, whence the Shots are made, that not only rafe the oppofite Face to be defended, but alfo enter with- in it.

The Word is form'd of ficher, to flick a Thing in.

FICHE, in Heraldry; fee Fitchee.

FICTION, fee Fable, Fallacy, £-*r.

FIDDLE, fee Violin.

FlVE-fri/for, in the Civil Law, is the fame with Re- promiflbr, Adpromiftbr, Sponfor, Pnedes, and Vades ; that is, a Surety, or one that obliges himfelf in the fame Con- tract with a Principal, for the greater Security of the Creditor, or Stipulator.

VWBl-CommiJ/iim, in the Roman Law, the appointing of an Heir, or Bequeathing of a Leg/icy to a Perfon, on this View or Condition, that he furrender the Inheritance or Legacy to another Perfon, for whom the fame is ori- ginally meant: Or, it is an inheritance left in truft with any one, for the ufe of another. See Trustee.

Fidei-Commifla were much u'ed among the Romans. In the French Law the thing is become odious ; as being, ordi- narily, no other than an Expedient in favour of Perfons to ■whom the Laws forbad any thing to be given. In order to this, fome Friend was chofe, whom they trufted to make legal Heir, under a tacit Agreement, to deliver the Succef- fion to the Perfon incapacitated by Law: At length, the fame Expedient came to be ufed with regard to Perfons capable of inheriting; to whom the Teftator for particular Reafons did not care to leave the Succeffion directly.

As it happen'd, that the Fidei-CommiJJioners did not always faithfully reftore, what was trufted to them, Augu- Jlus took proper Meafures to oblige them thereto : To this End a Pretor was erected, whofe Bufinefs was reftrain'd to the fingle Matter of ' Fidei-CommiJJions. Juft. Lib. II. T. 23.

VlT)¥.l-Commiffioner, a Truftee, or Heir intrufted with Charge, to reftore the Inheritance or Succeffion to another Perfon.

A jR<fo'-commiffionary Heir had a Right to referve the Trebellianick Fourth to himfelf: as a Teftament was null without the Inftitution of an Heir; and it frequently hap- pening, that the Fidei-Commijfwner refufed to accept the Truft, upon which the Teftament fell to the Ground ; To engage fome body to accept it out of the Confideration of Advantage, the Tegafian Senatus-Confultum decreed, that the Fidei-Commiffioner fhould be at Liberty to retain a Fourth of the Fidei-commiffum.

By the •Trebellian Senatus-Confultum, a farther Regula- tion was made. And in courfeof Time, the two Senatus- Confulta, the Pegajlan and Trebellian, came to be con- founded under the Name of the Trebellian.

YWS.\-JuJJio, in the Civil Law, a Security, or Gua- ranty. See Guaranty.

FIDICINALES, in Anatomy, a Name given to feveral Mufcles of the Fingers, called alio Lmnbricalcs. See Lum- bricalls Manus.

FIEF, the fame with Feud, or Fee. See Fee.

FIELD, in Agriculture, apiece of Land, or Ground in- clofed, and fit for Tillage, to bear Hay, Grain, &c. See Tillage, Ploughing, Fallow, £Sjc.

Field, Campus, in Antiquity, is frequently ufed for a publick Place, or Square in a City, i$c. as the Field of Mars, Campus Martins ; and Field of Flora, Campus Flo- ra; in Rome ; the Field of May, Campus Maji, among our Anceftors, £?c. See Campus.

The Field of Mars whs denominated from a Temple of that Deity, built therein. It was the Scene, or Place of the Affemblies called Comitia. See Comitia.

Tarquin the Proud at length appropriated it to his own Ufes;— — But after the Expulfion of the Kings, the Con- fute