Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/731

 FLE

ers. 15- The fbrubby African conyza, with fage like leaves, and the fmell of camphor. 16. The Ihrubby African conyza, with hoary, hooked, rocket like leaves. 17. The Rofemary leaved fhrubby African conyza. 18. The blunt leav'd African conyza, with groundfel flowers. 19. The purple flowered fig- wort leaved Indian conyza; and 20. The conyza, with ferrated mullein like leaves. Tourn, Inft. p. 454, feq. The common jieabane Hands recommended by the old authors as a remedy for many cutaneous diforders. They had an opi- nion alfo, that the fmoke of it when burnt in a room deftroy- ed fleas, and other infecls. Flea Wort. See Psylium.

FLEAM (Cycl.) — There are many furgeohs in Germany who bleed, or perform the operation of phlebotomy with this in- itrumenr, which they ufe in this manner : they hold one fin- ger upon the end of it, which ferves as a handle, and applying the point to the vein they are to open, ftrike upon the back Over the point with one of the fingers of the othei hand, open- ing the vein much as farriers bleed horfes. Others ufe a fpring fleam, fomething like a fingle point of the fcarifying inftru- ment ufed in cupping ; and others employ a fort of inftru- ment in form of a dart; but as the pofltion and fize of the veins is different, in different fubjecls, no inftrument will ever be found fo ufeful as the common lancet of a proper fize. Hej/?er's Surgery, p. 274. FLEECE {Cycl.)— Golden Fleece. See the article Golden. FLEMENEFRIT, Flemenesfrinthe, or Flymenafryn- the, in our old writers, fignifies the receiving or relieving of a fugitive or outlaw. Leg. Inas,cap. 29. 47. LL. H.i. c.10,12. FLEMESWITE. Fleta, who writes of this word, interprets it

habere caialla fugitivorum. Flet. Lib. 1. c. 4. FLESUS, in zoology, a name ufed by fome authors, for the common flounder j the patter fluviatilis of moft writers* Bel- lonius, p. 1 1 3. FLESHY roots. See Fibrose roots. FLEXION, (Cycl.) in geometry. See Flexure. FLEXOR [Cycl.) — Flexor digitorum pedis accejforius, a flat and pretty long flefhy mufcle, iiituated obliquely under the fole of the foot, and from its fituation and figure, formerly called caro planta pedis quadrata.

It is fixed pofteriorly by one flefiiy portion, in the lower fide of the os calcis, and in the anterior tuberofity on that fide, and by the other in the ligament which joins this bone to the aftragalus. From thence the two other portions run obliquely to the middle of the fole of the foot, and there unite in a flat, long, and irregularly fquare mufcular mafs, which is fixed to the outer edge of the fafciculus of tendons of the flexor longus, to which it ferves as a franum in that place. IVmJlovfs Anatomy, p. 224. F lexor profundus, in anatomy, a name given by Cowper and fome other writers to the mufcle of the foot called alfo the perforans pedis, and the perodaflylaeus by Riolan, and fome others. See Perforans. FLEXURE, or Flexion, in geometry, is ufed to fignify that a curve is both concave and convex, with refpe£fc to a given right line, A p, or a fixed point, P, Thus the curve

FL i

CMD, having the part CM concave towards A^>, or P, and the part M D convex to the fame, is faid to have a flexure. And the point M, which limits the concavity and convexity, is called the point of contrary flexure. See Point of contrary flexure, Cycl. and Suppl.

This is to be underftood, when the point fuppofed to defcribe the curve, coming to M, continues its courfe towards the fame fide ; but if it turn backwards, as in the figures annexed, tho' the curve may either have a continued curvature, as in

Fig. 1. Fig. 2: Fig. 3. M

23

fig. 3. or have a cufpis point of reflexion, or of retrograda- tion, as in/SJ7. i. and/%. 2.

As to the method of finding the points of contrary flexure, fee L'Hofiital's Anal. Inf. Petits, Sea, 4. See alfo the head Point

LSSf?/' ***'■ Wte * r ° me neceffar / »™aion S of V ooipitai s rule are given.

FLIDETHRIFT, or more truly Slidethrift, is the game we now call /hovel-hoard, ft is otherwife called Jhove-groat,

FT mr- mentl0ned ,n :he &tut =- 33 H. 8. c. 9.

unruly horfe.
 * UNCi, in the manege, is the fiery and obftinate aaion of an

To fling bice a cow, is to raife only one leg, and give a blow with it. bee Yerk.

FT 5 r&™n Ck W ' th the hind Ie S s ' See Yerking, Cycl.

S^'n"^* 1 See Bowling.

i ,, ( I'^~\ he f P ;uks of fin which are produced by ftnking/taaga.nft fteel, are of the number of thefe things which cuftom has made familiar to us, but which we might find much matter of inquiry, if we would give way to reafon on the fubjefti '

The ftriking fire in this manner has probably been as old as the knowledge of fteel ; and fince the microfcope has been fa- miliar among us, it has been dilcovercd, that thefe fparks are io many fphencal balls of iron detached by the blow from the mafs, and rendered by the heat a fort of fcoria;. Kemp de Kenvyck, a very ingenious chemift, propofed it as a problem worthy the attempts of the curious to folve, and propofed the whole in thefe words; when a flint and fteel are ftruck toge- ther, if the fparks are received upon a white paper, they are found to be round maffes, which examined by the microfcope, are found to be melted and fcorified or vitrified iron, which will no longer anfwer to the magnet. It is therefore demand- ed, 1. Which of the two inftruments contributes moft to this change in the iron ? 2. What fubftance it is, that is employ- ed to this purpofe ? 3. In what manner the operation is per- formed; and 4. Why if iron be ufed inftead of fteel, the fparks are very few or none, when with fteel they are fo many ? Thefe queftions have appeared aimed unanfwerable, becaufe people fcarce knew how to conceive, that iron which requires fo long continued, and fo violent a fire to put it in fufion, could by means only of a flight blow, be not only melted, but deftroyed as it were.The moft eminent perfons of the time declined engaging in the attempt, and Mr. Mufchenbrok, from whom a folution was expeSed by many, at length referred the whole to Mr. de Reaumur, who had fome time before pub- lished a treatife on iron and fteel, and was therefore judged to. have moft considered the metal in both thofe ftates. This gentleman accepted the task, and attempted the folution of the problem by refolving thefe queftion. I. By what means the iron is in this aQ converted into fcoria; ? 2. By what methods it can be fo deftroyed? 3. How it comes not only to be reduced to fcoria;, but to be in a ftate of fufion, and truly ren- dered liquid, and 4. Why iron gives lefs as well as fewer fparks on colliiion with flint than fteel does ? The nature of iron is well enough known for us to be affured that it contains a large portion of inflammable matter, and that it is never duftile, but while it has a quantity of that inflammable matter in it; and that when that is wholly taken from it, it becomes friable, and is reduced to a fort of fcoria;, analogous to common vi- trified matters.

What much conduces to the explication of the given problem, is, that this inflammable matter contained in iron is very eafi- fily fcparated when iron is heated in an open lire ; which is evidently feen, in that it is impofiible to heat a bar of iron in a fmith's forge, fo much as to make it ready for working or joining with another bar, without reducing its whole furface to fcoria;, or a friable matter which is all thrown oft" from the bar by the blows of the hammer.

The (mailer and thinner a piece of iron is, the more eafily is it reduced to fcoria;, and it is eafy to conceive from fence, that in pieces extremely fmall, there requires no more rhan the once thoroughly heating them to reduce the whole to fcoiiae ; and it i s eafily proved by experiment, that the flame of a can- dle being applied to a fine fmall piece of filings of fteel, will foon make it red hot, and that if it be then fuffered to cool and laid on a white paper, it will be found much to refcmble the fparks thrown off by flint and fteel, and will be reduced to fcoria; and he friable under the nail, like a piece of char- coal.

It appears then, that there requires but an inftant of time to give a red heat to a fmall particle of iron ; and alfo that when that heat has been given, the particle muft have loft that inflammable matter which caufed its duflility, and confequent- ly muft be reduced to fcoria; ; and hence it appears not won- derful, that the very fmall piece or particle of fteel which is ftruck off by the flint, fhould be divefted of its inflammable matter, and with it of its ductility, by being kept red hot in the open air, only fo long as it was in falling from the fteel to the paper that is placed to receive it. The extreme fmallnefs of the particle gives power 10 fo fhort a heat to deftroy its in- flammable matter, in which its ductility confifts ; and there- fore to reduce it to a matter no longer dudf ile, that is, into fco- ria;; and we find that if a parcel of fine fteel filings be dropt thro' the flame of a lamp driven into an horizontal direction by the blaft of a blow-pipe, they will in the inftant of their v

pafling