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charcoal. It communicates a yellow colour, scarcely visible, to the fluxes; and when the quantity is large, the globule, on cooling, contracts more or less of a white opacity. It is not precipitated by copper when dissolved; nor do the metals precipitate it from sulphur in the same order as from the acids. When united to carbonic acid, it grows red on the first touch of the flame; when the heat is increased it melts, and is reduced to a multitude of small globules. When united with phosphoric acid it melts, and yields an opaque globule, but is Got reduced. With fluxes it shows the same appearance as oxide of lead. When mineralized by sulphur, lead easily liquefies, and being gradually deprived of the volatile part, viekis a distinct regulus, unless too much loaded with iron. It may be precipitated by iron and copper.

A small piece of copper, either solid or foliated, sometimes communicates a ruby colour to fluxes, especially when assisted by tin or turbith mineral. If the copper is a little more or further calcined, it produces a green pellucid globule, the tinge of which grows weaker by cooling, and even verges towards a blue. By long fusion with borax, the colour is totally destroyed upon charcoal, but scarcely in the spoon. When once destroyed, this colour can scarcely be reproduced by nitre; but it remains fixed with microcosmic salt. If the calx or metal to be calcined is added in considerable quantity during fusion, it acquires an opaque red on cooling, though it appears green while pellucid and fused; but by a still larger quantity it contracts an opacity even while in fusion, and upon cooling a metallic splendour. Even when the quantity of copper is so small as scarcely to tinge the flux, a visible pellicle is precipitated upon a piece of polished iron add. ed to it during strong fusion, and the globule in its turn takes the colour of polished iron; and in this way the smallest portions of copper may be discovered. The globule made green by copper, when fused in the spoon with a small portion of tin, yields a spherule of the latter mixed with copper, very hard and brittle: in this case the precipitated metal pervades the whole of the mass, and does not adhere to the surface. Cobalt precipitates the calx of copper dissolved in the spoon by a flux, in a metallic form, and imparts its own colour to glass, which nickel cannot do. Zinc also precipitates it separately, and rarely upon its own surface, as we can scarcely avoid melting it. When mineralized by the carbonic acid, copper grows black on the first contact of the flame, and melts in the spoon; on the charcoal the lower part, which touches the support, is reduced. With a superabundance of marine acid, it tinges the flame of a beautiful colour; but with a small quantity shows no appearalice of the metal in that way. Thus the beautiful crystals of Saxony, which are cubic, and of a deep green, do not tinge the flame, though they impart a pellucid greeuness to microcosmic salt. An opaque redness is easily

obtained with borax: but M. Bergman could not produce this colour with microcosmic salt. Copper simply sulphurated, when cautiously and gently roasted by the exterior flame, yields at last by fusion a regulus surrounded with a sulphurated crust. The mass roasted with borax separates the regulus more quickly.

If a small quantity of iron happens to be present, the piece to be examined must first be roasted, after which it must be dissolved in borax, and tin added to precipitate the copper. The regulus may also be obtained by sufficient calcination and fusion, even without any precipitant, unless the ore is very poor. When the pyrites contain copper, even in the quantity of the one-hundredth part of their weight, its presence may be detected by these experiments. Let a grain of pyrites, of the size of a flax-seed, be roasted, but not so much as to expel all the sulphur; let it then be dissolved by borax, a polished rod of iron added, and the fusion continued until the surface when cooled loses all splendour. As much borax is requir ed as will make the whole of the size of a grain of hemp-seed. Slow fusion is injurious, and the precipitation is also retarded by too great tenuity; but this may be corrected by the addition of a little lime. Too much calcination is also inconvenient; for by this the globule forms slowly, is somewhat spread, becomes knotty when warm, corrodes the charcoal, destroys the iron, and the copper does not precipitate distinctly. This defect is corrected by a small portion of crude ore. When the globule is properly melted, according to the directions already given, it ought to be thrown into cold water immediately on stopping the blast, in order to break it suddenly. If the copper contained in it is less than one-hundredth part, one end of the wire only has a cupreous appearance, but otherwise the whole.

Dr. Gahn has another method of examining the ores of copper, namely, by exposing a grain of the ore, well freed from sulphur by calcination, to the action of the flame driven suddenly upon it by intervals. At those instants a cupreous splendour appears on the surface, which otherwise is black; and this splendour is more quickly produced in proportion as the ore is poorer. The flame is tinged green by cupreous pyrites on roasting.

Forged iron is calcined, but can scarcely be melted. It cannot be melted by borax, though it may by microcosmic salt, and then it be comes brittle. Calcined iron becomes magnetic by being heated on the charcoal, but melts in the spoon. The fluxes become green by this metal; but in proportion as the oxygen is more abundant, they grow more of a brownish yellow. On cooling, the tinge is much weakened, and when originally weak, vanishes entirely. By too much saturation the globule becomes black and opaque. The sulphureous pyrites may be collected into a globule by fu sion, and is first surrounded by a blue flame; but as the metal is easily calcined, and changes

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which it spontaneously falls, resembling very minute granulations: denominated fluor mineral, or granular. Found in Britain, Norway, Sweden, Spain, and Germany, white, smokecolour, green, violet, purple, rosy, honey-colour, or varied with spots, blotches, or veins, semi-pellucid, or transparent, breaking into three, rarely four-sided fragments, takes a fine polish, and is manufactured into various vases and figures.


bles. Saxony.

4. F. tabularis. In rhombic oblong taFound in Switzerland, Alsace, and

5. F. cubicus. Fluat of lime. Cubic fluor. Hardish, shining, smooth, lamellar, brittle, breaking into pyramidal fragments, cubie...». Many varieties, cubes perfect; or imperfect; angles, or margins, or both truncate; margins terminating in a point, or in a three-sided pyramid. Found in Derbyshire and Northumberland, Spain, France, Saxony, Germany, &c. of the same variety of colours as F. spatosus; most frequently pellucid, rarely opake; the crystals solid or hollow, or containing a small drop of water, or some fossil, and placed in a decussate manner, laterally or irregular, or aggregate in a kidney or imperfectly globular form.

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to women, commonly known by the name of whites. See MEDICINE, and LEUCORRHOEA. FLUORI ACID. See FLUORIC SPAR. FLUORIC SPAR. (acide fluorique, French; fluss spathsuure, Germ.). In the Transactions of the Academy of Sciences at Berlin for 1763, is contained a memoir by Margraaf on fluor spar. This able chemist found that when the above mineral was distilled with sulphuric acid a volatile acid vapour was disengaged, which deposited a white earth on coming into contact with water; he also remarked that the retort in which the distillation was carried on was corroded and worn into holes by the process. Three years after, Schee'e published valuable essay on the saine subject, in which he proved that fluor spar consisted of lime combined with a peculiar acid, many of the properties of which were investigated by him with great success. Priestley then took up the subject, confining his attention for the most part to the action of fluoric acid in the state of ga-s. Since the date of these last experiments but few additions have been made to our knowledge of this acid and its various combinations.


manuer deposited if the gass is received in water, and this experiment, according to the circumstances under which the acid is disengaged, exhibits a variety of singular and interesting appearances. As soon as a bubble of gass passes from the beak of the retort into the water it is immediately diminished in size from the absorption of a portion of the acid, and the whole would be taken up if the globule did not instantly become coated with the earth deposited by that part of the acid which is absorbed, for the earthy film being interposed between the gass and the water prevents any further combination till the bubble reaches the surface of the water, where it bursts. If this is performed in a jar full of water inverted over mercury, and care is taken to prevent the gass from being mixed with atmospheric air, the whole of the gass is absorbed, and the silex, in proportion as it is deposited, diffuses itself through the liquor, which thus at length acquires a gelatinous consistence: when in this state, the greater part of the earth may be separated by putting the whole in a piece of linen and squeezing it. The acid liquor thus procured being again inverted over mercury, will absorb an additional quantity of gass, and by thus treating it three or four times successively, a strong fuming acid liquor may be obtained, consisting principally of fluoric acid and water, but still holding in solution a portion of silex, and probably also alkali, from the decomposition of the glass of the retort. If this saturated liquor is mixed with a few drops of fluat of silver, a slight precipitate of cornea takes place, and the fluoric acid is thus separated from a small portion of muriatic acid, which, when prepared in the foregoing manner, it is always fond to contain. From the liquor thus purified a considerable quantity of pure Aluoric acid gass may be obtained by heating it almost to ebullition in a retort, and receiving the product in mercury. This gass appears to consist merely of fluoric acid, saturated with as much water as it can hold in an elastic state, and at a moderately cool temperature seems to have no action on glass. It combines readily with water without depositing in any earth, and has an astringent acidulous taste. A candle immersed in it is extinguished without any previous change in the colour of the flame: it combines with ammoniacal gass, forming a white cloud: it dissolves camphor, and is taken up in large quantity by oil of turpentine, to which it communicates an orange colour and a pungent acid odour. If kept for some time in a bottle of soft glass it acts upon it though slightly, on which account it is a useful precaution before putting the acid in, to line the bottle with a thin coating of a mixture of oil and wax. It has been proposed by some chemists, as a method of obtaining pure liquid fluoric acid, to make use of a leaden retort and receiver; in which case the fluor spar being previously reduced to an exceedingly fine powder, is to be mixed in the retort with an equal weight of strong sulphuric acid; the application of a gentle heat, not exceeding that of

The distinguishing property of fluoric acid is that when dry and in the state of gass it readily combines with silex, and still retains its elastic form: hence arises the peculiar and almost insurmountable difficulty of obtaining this substance in a state of purity.

Fluoric acid is procured from fluor spar: for this purpose a quantity of the mineral being reduced to a fine powder is to be mixed in a thick glass retort with an equal weight of concentrated sulphuric acid: upon the application of a gentle heat the sulphuric acid will combine with the calcareous base of the spar, and fluoric gass will at the same time be liberated, and may be received in the mercurial pneumatic apparatus in the usual way. If the heat applied to the retort is somewhat considerable, and the gass is rapidly produced, the retort will give way in the space of a minute or two, being eaten into holes by the action of the acid; if the process is conducted cautiously and at as low a temperature as possible, the retort may be made to last a considerable while longer. The gass thus procured, while confined over mercury, is perfectly colourless and transparent; it has a pungent suffocating odour like muriatic acid, produces immediate death to animals which are immersed in it, extinguishes the flame of a candle after having previously tinged its flame of a green colour, and changes certain vegetable blues to red. Its specific gravity is considerably greater than that of atmospheric air, but has not yet been ascertained with any accuracy. If this gass is mixed with atmospheric air, a white vapour similar to but more copious than that occasioned by the muriatic acid gass in the same circumstances is the result; this appearance is partly occasioned by the combination of the acid with the moisture of the air, but principally by the deposition of silcx, which takes place at the same time. The earth is in like

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boiling water, will force into the receiver a large quantity of acid gass, where it combines to saturation with water, and thus produces liquid fluoric acid. In this process, provided the spar selected was free from quartz, there is indeed no deposition of silex, but a very notable proportion of lead is volatilized, and remains for the most part dissolved in the Equor, which, on this account, is by no means so pure as the acid produced by Dr. Priestley's


Fluoric acid has not yet been decomposed, its base therefore is wholly unknown, and it is only from analogy that chemists suppose it to contain oxygen. A remarkable difference between the fluoric and muriatic acid is that the latter is incapable of becoming oxygenated: it will neither unite with oxygen in the state of gass nor when digested with manganese. Fluoric acid combines with the alkalies and alkaline earths, with alumine and silex, and with the metallic oxyds; the metals in a reguline state appear to have no affinity for dry fluoric acid, but when liquid it will dissolve iron, zine, copper, and arsenic, hydrogen being at the same time disengaged. The order of its affinities is as follows: lime, barytes, strontian, magnesia, potash, soda, ammonia, alumine, and silex.

The only use to which fluoric acid has been applied is engraving on glass. It appears from Beckman that this was first practised by an artist of Nuremberg, in the year 1670, who prepared his etching liquor by digesting together nitrous acid and finely powdered fluor spar for several hours on a warm sand bath, and then using the clear liquor as aquafortis is employed by the copper-plate engravers. But the knowlege and application of this liquor was confined to a few German artists, till, after the discoveries of Scheele and Priestley, the fluoric acid in a pure state was used for the same purpose by various ingenious artists in England and France. Puymaurin found the liquid acid prepared in leaden vessels according to Scheele's process to answer very well for this purpose in warm weather, but by cold its activity is so much impaired as to produce little effect even in three or four days. The gasseous acid however is much more efficacious; and being at the same time sufficiently manageable with proper care, merits the preference. To engrave on glass, select a piece of plate glass of the requisite size, cover it with hard engraver's wax, and with a needle or other suitable instrument trace the intended design as in common etching, observing that every stroke passes quite through the wax to the surface of the glass; which may be ascertained by placing the plate on a sloping frame like a portable reading-desk, in which situation the light will shine through wherever the wax is removed. When the etching is completed, lay the plate with the engraved side downwards on a frame, in a box lined with strong sheet lead or thick tin foil, and place on the bottom of the box a few leaden cups containing a

mixture of one part of very fine pulverized fluor spar and two parts of sulphuric acid: then close the lid of the box, and place it on a stove, or in any other convenient situation where it may be exposed to as high a heat as it can bear without risking the melting of the wax: fluoric acid gass will be copiously disengaged, and in a short time (from one hour to three, according to circumstances) the plate will be found sufficiently corroded. See FLUOR.

FLURRY. s. 1. A gust of wind; a hasty blast (Swift). 2. Hurry; a violent commotion.

To FLUSH. v. n. (fluysen, Dutch.) 1. To flow with violence (Mortimer). 2. To come in haste (Ben Jonson). 3. To glow in the skin (Collier). . 4. To shine suddenly: obsolete (Spenser).

To FLUSH. v. a. 1. To colour; to redden (Addison). 2. To elate; to elevate (Atterbu.). FLUSH. a. 1. Fresh; full of vigour (Cleave.). 2. Affluent; abounding (Arbuthnot).

FLUSH. S. 1. Afflux; sudden impulse; violent flow (Rogers). 2. Cards all of a sort.

FLUSHING, a handsome, strong, and considerable town in Zealand, and in the island of Walcheren, with a good harbour, and a great foreign trade. It was put into the hands of queen Elizabeth as a security for the money she advanced. It is one of the three places which Charles V. advised Philip II. to preserve with care. It is four miles S. W. of Middleburg. Lon. 3. 35 E. Lat. 51.29 N. This town was taken, in August, 1809, by the English under the command of earl Chatham.

To FLUSTER. v. a. (from To flush.) To make hot and rosy with drinking (Shakspeare).

FLU'STRA. Horn-wrack. In zoology, a genus of the class vermes, order zoophyta. Animal, a polype proceeding from porous cells; stem fixed, foliaceous, membranaceous, consisting of numerous rows of cells united together and woven like a mat. Eighteen species; inhabitants of the European or Mediterranean seas; one or two of the Indian and Atlantic; eight found on the British coasts; adhering to fuci or other submarine substances,

F. chartacea may serve as an example. This, as its name evinces, is papyraceous, or of a thin semitransparent texture, like fine paper; of a very light straw colour, with cells on both sides: the tops of the branches sometimes digitated, sometimes irregularly divided, and truncate like the edge of an axe: the cells are ob long square. It is found on the British shores, adhering to sea-wrack, shells, and rocks.

FLUTE, a musical instrument, the most simple of those which are played by the breath impelled from the lips. The common fute, or flute a bec, is a tube about eighteen inches in length and one in diameter; it has eight holes along the side, and the end is formed like a beak, to apply the lips to. The German flute consists of a tube formed of several joints or pieces screwed into each other, with holes disposed along the side, like those of the

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