Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/732

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fesffing thro' that flame, fparkle and become ignited, and if theyare received on a white paper placed underneath, thefmal- eft particles will be found round and friable, reduced to fcorize, no way differing from the little globules of fcorified fteel, which are ftruck off from the pit and fteel in giving fire by their collifion.

When we have occafion to melt larger parcels of fteel or iron, we are obliged to have recourfe to fuch fubftances to mix with them as will replace with increafe that inflammable matter which the fire drives off: the fubftances of this kind are com- mon fulphur, orpiment, arfenic, and the like ; and by means of thefe, it is foon made to run like lead. Memoires Acad. Scien. Par. 1736.

Mr. Reanmur having given thefe hints for the underftanding the occafion of iron's being found fcorified by the fhort heat it receives from the collifion of flint and fteel, proceeds to ac- count for the reafon why iron yields fewer fparks with flint than it does with fteel.

On this occafion he obferves, that he accidentally had difcover- ed a new phofphorus of iron, in giving the procefs of which, great light would be thrown into this fubject : the method of making it was this, having melted fome antimony in a cruci- ble, he threw in at feveral times, twice the quantity of iron reduced into thin fcales ; the whole foon melted together, and became one fluid mafs; when this had been caft into a mould and was become cold, it afforded a long train of fparks on be- ing filed with a common coarfe file. The fparks were much larger than thofe produced by a collifion of fiint and fteel, and the larger of them fet fire to the paper placed to receive them; but upon examination, thefe were all found to be melted in the manner of the fparkling particles ftruck off from fteel, not only burnt, but melted, and that more perfectly than the others from the common collifion withy//?//. If after all this, it be ask'd, why fteel yields greatly more numerous fparkles than iron ? the anfwer is plain, that the difference of hardnefs alone is fufficient to occafion it ; but granting even that fteel and iron were of equal hardnefs, fteel has the fame advantage of iron in this refpect, that the before mentioned mixture of iron with antimony has over plain iron, in that it contains greatly more of the inflammable matter than the iron does, and this in- flammable matter is alfo more equally diftributed thro' all its lu r face.

It may alfo be judged, that the flint not only contributes by its hardnefs to the fending off the fparks, but alfo by its fulphur; what the blow diflodges from it of this kind, and puts in vio- lent motion, probably having no final! effect both in the fu- fion and fcorification of the metal. That all flints contain a large quantity of fulphur is plain, from the fulphureous fmell they afford on being ftruck together ; and the fparks which are produced by f hiking iron againft iron are probably affected in the fame manner, by the fulphur of the metal diflodged from the adjoining parts by the blow.

One great proof of the fparks being melted and rendered glo- bular by means of the fulphur of the flint is, that fparks may be ftruck from fteel, in the fame manner by glafs as by flint, but in Iefs quantity 5 thefe having been received on a paper, were examined by Mr. Reaumur, and were found to be fco- rjge, of an irregular figure, having never been melted, and therefore never reduced to the globular fiiape of the others. In regard to the great change wrought in iron by this opera- tion, or its being according to the words of Kemp deftroyed, no longer retaining its great character of being attracted by the loadftone, Mr. Reaumur willing to try the experiment be- fore he reafoned upon it, found this after tion not to be a fact, or at leaf! not a general one.

All the feveral kinds of fparks which he mentions, thofe pro- duced by the common collifion of flint and fteel, thofe by dropping fteel filings thro' the flame of a lamp, and even thofe from the filing of the antirnoniatcd iron, all as readily anfwer- ing to the loadftone as common filings of iron ; fo that if this cafe fometimes happen, and iron be liable thus to be deftroyed, it is however no general fact, but a very rare and extraordi- nary one. Memoris Acad. Par. 1736. Flints, in the glafs trade. The way of preparing flints for the niceft operations in the glafs trade is this. Chufe the hard- tft flints, fuch as are black and will refift the file, and will grow white when calcined in the fire. Cleanfe thefe of the white cruft that adheres to them, then calcine them in a ftrong fire, and throw them while red hot into cold water; wafh off the alhes that may adhere to them, and powder them in an iron mortar, and fift them through a very fine fieve; pour upon this powder fome weak aqua fortis, or the phlegm of aqua fortis, to difiblve and take up any particles of iron it may have got from the mortar ; ftir this mixture feveral times, then let it reft, and in the morning pour off the liquor, and wafh the powder feveral'times with hot water, and afterwards dry it for ufe. You will thus have a powder for making the .pureft glafs as perfectly fine and faultlefs, as if you had ufed rockcryftal icfelf. C?-amer'$ Art of affayins; metals, p. 43S. The wafbing off the ferrugineous particles with aqua fortis is »ut neceilliry, when the glafs intended to be made is to be ting-

FLO

ed with iron afterwards; but when meant to be a pure whit*;, this is the method to be fure of fucceeding. Breaking of Flint. — The art of cutting or rather breaking flint ftones into uniform figures, was by fome iuppofed to be one of the arts now loft. That it was known formerly ap- pears from the antient Bridewell at Norwich, from the gate of the Auftin-friars at Canterbury, that of St. John's abbey at Colchefter, and the gate near Whitehall Weftminfter. But that the art is not loft, and that the French know it, ap- pears from the platform on the top of the royal obfervatory at Paris, which inftead of being leaded, is paved with flint, in the manner here mentioned. But we know not that this art is any where defcribed. Phil. Tranf. N?, 477. p. 521, and Note ibid. Oil of Flints, a name given by fome to a preparation made of four ounces of flints calcined and powdered and mixed with twelve ounces of fait of tartar ; thefe being melted together by a ftrong fire, run into a glafs, which being afterwards pow- dered and let in a cellar, runs into an oil per deliquium ; with this and the calx of any metal is prepared, one of the metal- lic vegetations. See Vegetations metallic. FLOATING {Cycl.) — Floating-£W<^?, a bridge confuting of feveral boats covered with planks ; which ought to be fo folidly framed, as to bear both horfes and cannon. See Bridge, Cycl. and Suppl Floating iftands. See Islands.

FLOOD (Cycl.) — Fioon-mark, the mark which the fea makes on the fhoar, at flowing water, and the higheft tide : it is al- fo call'd high-water mark. Sand Flood. See Sand.

FLOOKING, a term ufed in mining to expref3 a peculiarity in the load of a mine. The load or quantity of ore is frequent- ly intercepted in its courfe, by the croffing of a vein of earth or ftone, or fome different metallic fubftance ; in which cafe the load is moved to one fide, and this tranfient part of the land is called a flooking. See Mine. FLOOR (Cycl.) —Floor- timber, in a {hip. See Timber. FLORAL leaf, among botanifts. See Leaf. FLORE6 1 argenti, in natural Hiftory, a name given by fome to the earth, called by the generality of authors, lac luna?. It has both thefe names from its being fuppofed to partake of the nature of filver. See the article Lac /»»#■, Cycl. and Suppl. Flores Martiales, a name given to a preparation of the nature of what was formerly called ens veneris. Thefe flowers are thus prepared; take of warned colcothar or green vitriol, or of iron filings one pound ; of fal armoniac, two pounds ; mix them, and fublime them in a retort, and mixing again the bottom with the flowers, renew the fublimation till the flowers acquire a beautiful yellow colour. To the rtfidue may be ad- ded half a pound of frefh fal armoniac, and the fublimation repeated, and the fame procefs may be continued as long as the flowers arife duly coloured. Pcmberton's Lond. Difp, p. 215. FLORIST, Florijla, in botany, an author who writes what is called the flora of any particular place, that is, a catalogue of the plants and trees which are found fpontaneoufly growing there. The flora laponica of Linnseus, and flora virgmiea of Gronovious, are works of this kind ; and thefe authors, as the authors of thofe works, are properly called florijla;. Linn. Fundam. Bot. p. I. FLORUS, in zoology, a name by which Aldrovand and fome other authors have called the bird commonly known with us by the name of the whinchat, a kind of the xnantbe or fal- low-finch. Mdrovand, de Avibus. See Whinchat. FLOS, the flower of a plant. It is to be obferved that the an- tients fometimes called the ftamina or threads in the center of flowers, the flos, and not the petals which we ufually call fo. Without underftanding this, it is not poffible to underftand many paflages in their writings. We find in Aurelian, the rofe called a yellow flower ftanding in a purple husk; it is plain by this, that he meant the threads in the middle of that flow- er, which are of a fine yellow, and are very numerous, by the word flower ; and calls the fine purple petals which we efteem the flower, only the husk of the flower ; in this fenfe Virgil is explained to mean the common baum by the name ameilo ; he fays it has a yellow flower and purple leaves at the bottom, and they fuppofe that he meant the ftamina or threads which in the baum are yellow, by the name flower j and the calyx or cup of the flower which is a purple, by his expreflion of leaves at the bottom. The antients in general do not feern determined as to what they would have underftood by the word flos. In the narciflus, Pliny calls the cup that yellow part which occupies the center, and the whitifh leaves that furround it the flower. Pliny has been cenfured for calling this part of the flower the cup, but he does not by this mean to confound it with the green leaves in the generality of plants which furround the flower, but he calls it thus in refemblance to the cups out of which they drank, in their feftivals. Flos arts. See the article .Ms.

Flos ambarvalis, in botany, a name given by fome to the poly- gala or milkwort. Merm, Cat. p. 450.

Flos