FL

FLU

LUKES. Worms of the intestinal order, found frequently in the liver and brain of sheep, and the chief source of the rot. See FASCIOLA.

FLUMMERY. s. A kind of food made by coagulation of wheat-flower or oatmeal (Loc.). FLUNG. The participle and preterit of fling.

FLUOR, in oryctology, a genus of the class earths, order calcareous. Consisting of carbonat of lime and fluoric acid; somewhat ponderous, parasitical, never hard, shining in the dark, and crackling when heated to the degree of boiling water; not effervescing with acids; but if distilled with the mineral acids, emitting the fluoric acid gass which has the property of dissolving glass; melting before the blowpipe into a transparent glass. Six species.

1. F. pulverulentus. Sandy or earthy fluor. Earthy fluat of lime. Whitish, without lustre, powdery, with the larger particles not cohering. Found at Kabola Poiana in the district of Marmaros in Hungary, between two beds of quartz; colour light gray, greenish white, or blueish green; when strewed on an iron plate a little below redness diffusing a blue or pale yellow phosphorescent light; feels harsh and stains a little.

2. F. compactus. Solid or compact fluor. Hardish, compact, of an even texture, diaphonous, brittle, breaking into indeterminate fragments, of a common form. Found in Britain, and near Stolberg and Strasburg, whitish-grey, more or less passing into green, often spotted; fracture even or conchoidal, specific gravity from 3,120 to 3,165.

3. F. spatosus. Fluor spar. Sparry fluor. Hardish, shining, brittle, of a common form breaking into pyramidal fragments, lamellar. Another variety, with the fragments into VOL. V.

FLU

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.

4. F. tabularis. In rhombic oblong tables. Found in Switzerland, Alsace, and Saxony.

5. F. cubicus. Fluat of lime. Cubic fluor. Hardish, shining, smooth, lamellar, brittle, breaking into pyramidal fragments, cubic. 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.

6. F. pyramidalis. Pyramidal fluor; fluor fluat of lime.

spar,

a

With a single pyramid, inversed, or straight, or three-sided, or truncate, or six-sided.

With a double pyramid; the pyramid sour-sided. Found in Derbyshire, Devonshire, and Cornwall; and in various parts of Sweden, Saxony, and Bohemia: the colours vary as in F. spatosus. See FLUORIC SPAR.

FLUOR ALBUs, a morbid secretion incident B

to women, commonly known by the name of whites. See MEDICINE, and LEUCORRHOEA. FLUORIC ACID. See FLUORIC SPAR. FLUORIC SPAR. (acide fluorique, Fr. fluss spathsaure, 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, Scheele published a valuable essay on the same 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 gas. Since the date of these last experiments but few additions have been made to our knowledge of this acid and its various combinations.

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 gas 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 gas 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 silex, which takes place at the same time. The earth is in like

manner deposited if the gass is received in water, and this experiment, according to the circumstances under which the acid is disen◄ gaged, exhibits a variety of singular and interesting appearances. As soon as a bubble of gas 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 gas 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 gas, 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 decomposttion 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. found to contain. From the liquor thus purified a considerable quantity of pure fluoric acid gas 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 inmersed 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 hottle 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