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as high above the head as in the usual manner As the greatest part of my estate has hitherto been of planting them. Thus they would be pre- of an unsteady and volatile nature, either tossed served from the danger of rotting; their fibres upon seas, or fluctuating in funds, it is now fixed and would be much stronger, and consequently they settled in substantial acres and tenements. Addison would draw more nourishment, and flower better The fluctuating fields of liquid air, than in the common way. The ordinary method With all the curious meteors hovering there, of planting these roots renders them liable to

And the wide regions of the land, proclaim

The Power Divine, that raised the mighty frame. be destroyed by either extreme of a wet or dry

Blackmore. season: in the former case, they immediately rot by the superabundant moisture; and, in the

FLUDD (Robert), the son of Sir Thomas latter, they become as dry as a stick and mouldy, Fludd, was born at Milgate in Kent, in 1574. so that the first rain thai falls afterwards infalli- He was educated at St. John's College, Oxford, bly rots them.

where he took his degrees in arts, after which Flo'wer de Luce, n.s. From Fr. fleur de lis. he travelled abroad. He returned to England A bulbous iris.

in 1605, took the degree of M. D. and became

fellow of the college of physicians in London. Cropped are the flower de luces in your arms : Of England's coat one half is cut away.

He was a most voluminous writer; doated greatly Shakspeare.

on the wonders of alchemy; was a zealous broThe iris is the flower de luce.

Peacham. ther of the Rosicrucian order; and his books, Flower'INGBUSH, n. S. A plant.

which are mostly in Latin, are as dark and

mysterious in their language as in their matter. FLOWK, n. s. Scott. fluke. A founder; the He died in 1637. name of a fish. See FLOUNDER.

FLUE, n. s. A word of which I know not Amongst these the flowk, sole, and plaice, follow the etymology, says Dr. Johnson, unless it be the tide up into the fresh waters.

Carer. derived from flew of Ay. Mr. Todd suggests the Flowk'wort, n. s. The name of a plant. Fr. l'ouverte, an opening: Mr. Thomson, with

FLOWN, participle of fly. Gone away ; more probability, the Lat. flatus ; a puff or blast puffed ; inflated ; elate.

as its origin. A small pipe or chimney to conFor those,

vey air, heat, or smoke. Soft down or fur, such Appointed to sit there, had left their charge, as may fly in the wind. Flown to the upper world. Milton's Paradise Lost.

FLU'ELLIN, n. s. The herb speedwell

. And when night

FLU'ENCY, n. s. Lat. ftuens, fluo; d Darkens the streets, then wander forth the sons FLU'ENT, adj. & n. S. Gr. Bauw. The adjecOf Belial, flown with insolence and wine. Id. FLU'ENTLY, udv. tive is the etymon; and

Where, my deluded sense! was reason flown? literally signifies flowing, liquid; the motion of Where the high majesty of David's throne ? water in flux: thus it is also applied to what


ever is ready; copious; voluhle. The noun Is this a bridal or a friendly feast ?

signifies the quality of flowing; smoothness ; Or from your deeds I rightly may divine, freedom from harshness or asperity; affluence; Unseemly flown with insolence or wine. Pope.

abundance: but the latter sense is obsolete. FLUCʻTUATE, v. n.

Lat. fluctuatus, part.

God riches and renown to men imparts, Fluc'TUANT, alj. of fluctuo from fluctus, Even all they wish ; and yet their narrow hearts FLUCTUATION, n. S.

It conveys Cannot so great a fluency receive, the idea of strong agitation: it expresses the But their fruition to a stranger leave. Sindys. motion of the waves perpetually heaving back wards and forwards : hence it is applied to what- better grace in youth than in age, such as is a fluent

Those have some natural dispositions, which have ever is uncertain, or is the subject of sudden and luxurious specch.

Bacon. vicissitudes. Applied to the mind, it signifies It is not malleable; but yet is not fluent, but stu. to be irresolute; undetermined.


Id. The Tempter, but with shew of zeal and love Motion being a fluent thing, and one part of its duTo man, and indignation at his wrong,

ration being independent upon another, it doth not Wew parts puts on, and as to passion moved,

follow that because any thing moves this moment, Fluctuates disturbed, yet comely and in act

must do so the next.

Ray on the Creation. Raised, as of some great matter to begin.

Confiding in their hands, that sed'lous strive Milion's Paradise Lost. To cut the outrageous fluent ; in this distress, Fluctuations are but motions subservient, which Even in the sight of death.

Philips. winds, storms, shores, shelves, and every interjacency Fluency of numbers, and most expressive figures for irregulates.

Browne. the poet, morals for the serious, and pleasantries for Even the influence of superstition is fluctuating and admirers of points of wit.

Garth. precarious; and the slave whose reason is subdued, The common fluency of speech in many men, and will often be delivered by his avarice or pride. most women, is owing to a scarcity of matter, and a

Gibbon. scarcity of words ; for whoever is master of language, It will not hinder it from making a proselyte of a and hath a mind full of ideas, will be apt, in speakperson, that loves fluctuation of judgment little ing, to hesitate upon the choice of both. Swift. enough to be willing to be eased of it by any thing but errour.

FLUID, adj. & n. s.

Lat. fluo, fluidus. See
FLUID'ITY, N. S. Fluency.

Fr. fluide, To be longing for this thing to-day, and for that thing to-morrow; to change likings for loathings, and

FLU'IDNESS, 11. s. fưidité. That which, to stand wishing and hankering at a ven!ure, how is from its nature, flows; that quality in bodies it possible for any man to be at rest in this fluctuant which is opposite to solidity and stability; any wandering humour and opinion? L'Estrange. thing not solid.





Dr serve they as a flowery verge to bind with as much force as concentrated sulphuric The fluid skirts of that same watery cloud, acid, and appears to operate by the production Lest it again dissolve, and shower the earth ? of water; for, while it carbonises these suh

Milton. What if we should say that fluidness and stability burning. Exposed to a high temperature, it is

tances, they may be touched without any risk of depend so much upon the texture of the parts, that by the change of that texture the same parts may be

not decomposed; and is condensed by cold withmade to constitute either a fluid or a dry body, and

out changing its form. When it is put in contact that permanently tw.


with oxygen, or air, either at a high or low temIf particles slip easily, and are of a fit size to be perature, it experiences no change, except seizing, agitated by heat, and the heat is big enough to keep at ordinary temperatures, the moisture which them in agitation, the body is fluid, and if it be api these gases contain. It may hence be employed to stick to things, it is humid.

Newton. with advantage, to show whether or not a gas Heat proinotes Huidity very much, by diminishing contains moisture. the tenacity of bodies : it makes many bodies fluid, No combustible body attacks fluoboric gas, which are noe fluid in cold, and increases the fluidity of if we except potassium and sodium, which, tenacious liquids ; as of oil, balsam, and honey; and with the aid of heat, burn in this gas, almost as thereby decreases their resistance.

Id. As when the fig's prest juice, infused in cream,

brilliantly as in oxygen. Boron, and fuate of To curds coagulates the liquid stream,

potash, are the products of this decomposition; the Sudden the fluids fix, the parts combine. Pope.

fluoboric gas being a compound of fuorine and Consider how luxury hath introduced new diseases, boron, the potassium unites to the former, giving and with them, not improbably, altered the whole rise to the fluoride of potassium, while the boron course of the fluids.

Arbuthnot. remains disengaged. Fluoboric gas is very soThe permanently elastic fluid generated in the fir- luble in water. According to Dr. John Davy ing of ytinpowder, is calculated by Mr. Robins to be water combines with 700 times its own volume, about 244, if the bulk of the powder be one.

or twice its weight, at the ordinary temperature Darwin.

and pressure of the air. Water saturated with FLUIDS, ELASTIC. See Aerology, Air, Fixed this gas is limpid, fuming, and very caustic. By Air, Gas, VAPOR, &c.

heat, about one-fifth of the absorbed gas may FLUIDS, Laws AND PROPERTIES OF. See be expelled; but it is impossible to abstract HYDROSTATICS.

It then resembles concentrated sulFlrKE-WORM. See FASCIOLA.

phuric acid, and boils at a temperature consiFLUMET, a town of France, in the depart- derably above 212°. It afterwards condenses ment of Mont Blanc, ci-devant duchy of Savoy, altogether in striæ, although it contains still a and lordship of Faussigny; seated on the Arly, very large quantity of gas. It unites with the among the mountains, thirty miles north-east of bases, forming salis, called Auoborates, none of Chambery, and thirty-one south-east of Geneva. which have been applied to any use in the arts.

FLUM'MERY, n. s. A kind of food, made See CHEMISTRY. by coagulation of wheat-four or oatmeal.

FLU'OR, n. s., Lat. A fluid state; catamenia. Milk and flummery are very fit for children. Locke.

The particles of fluids, which do not cohere too FLUMMERY is thus prepared: steep three strongly, and are of such a smallness as renders them !arze handfuls of finely ground oat-meal, for

most susceptible of those agitations which keep liquors twenty-four hours, in two quarts of fair water:

in a fluor, are most easily separated and rarefied into then pour off the clear water, and put two quarts vapours.

Newton's Opticks. of fresh water to it: strain it through a fine hair Hence silvery selenite her crystal moulds, sieve, putting in two spoonfuls of orange-flower And soft asbestos smooths his silky folds ; water and a spoonful of sugar: boil it till it is His cubic forms phosphoric fluor prints, as thick as a hasty pudding, stirring it con

Or rays in spheres his amethystine tipts., Darwin. tinually while it is boiling, that it may be very Fluor, in physics, signifies properly the state smooth.

of a body that was before hard or solid, but is FLUMS, a town of Switzerland, in the late reduced by fusion or fire into a state of fluidity. county of Sargans, on the Mat, five miles west Fluor, or Fluor-SPAR, in mineralogy, a of Sargans.

genus of calcareous earth, the eleventh of that FLUNG, participle and preterite of fling. class in Kirwan's arrangement, the octohedral Thrown; cast.

fluor of Jameson, and flus of Werner. It is Several statues the Romans themselves fire

into divided into three sub-species, viz. compact the river, when they would revenge themselves. fluor, foliated fluor, and earthy or sandy fluor.

Addism on Italy. 1. Compact fluor. Colors, greenish-gray and FLUOBORIC Acid. This is a gaseous acid, greenish-white. Dull or feebly glimmering. and may be obtained by heating in a glass re- Massive. Fracture even. Fragments sharptort twelve parts of sulphuric acid with a mix- edged. Harder than calcareous spar, but not so ture of one part of fused boracic acid, and two hard as apatite, the eighth of Kirwan's scale for of fluor-spar, reduced to a very fine powder, and hardness. Brittle, and easily frangible. Specific it must be received over mercury. "Its density gravity 3.17. It is found in veins, associated is 2:41; it is colorless; its smell is pungent, re- with sparry fluor, at Stolberg in the Hartz. sembling that of muriatic acid; it cannot be 2. Foliated fluor. Its colors are very numebreathed without instant suffocation; it extin- rous, pure, and greenish-white, or yellowish or guishes combustion; and reddens strongly the reddish-white, or gray or bluish-gray, or light tincture of turnsole. It has no manner of action or violet-blue, or grass, leek, or olive-green, or on glass, but attacks vegetable and animal matters dark red verging to purple, or purple inclining to

black, or wine or honey yellow, or yellowish- the strata seen by a microscopical examination brown. Many of these occur often in spots, of the specimen? blotches, or veins pervading the mass of one 3. Common sand, or earthy fluor. It is of a and the same specimen. It is found either light gray color and loose consistence; when annorphous, or crystallised; the most usual of strewed on an iron plate, heated a little below the crystallised forms is that of a perfect cube, redness, it diffuses a blue or pale-yellow phosthe angles or edges rarely truncated or bevelled; phoric light. According to the experiments of these last have sometimes concave planes. The Klaproth and Gmelin, it contains the fluor acid octohedral form is also sometimes met with. Its singly, and not the phosphoric. Mr. Pelletier surface mostly smooth, or frosted over with mi- found 100 parts of it to contain thirty-one of nute crystals. Lustre 2, 3. Transparency 2,3,4. silex, twenty-one of calx, 15-5 argil, 28.5 sparry Fracture foliated, generally straight, seldom acid, one of phosphoric acid, and one of iron. curved; some parts, however, are found splin- In an unconnected substance of this sort, diftery, as if passing into the compact. Fragments ferent specimens must undoubtedly contain diftend to the form of triangular or quadrangular ferent proportions of ingredients; among these pyramids, and present coarse or small-grained, the silex is evidently adventitious, the phosphoric seldom prismatic, distinct concretions.

acid being in such small quantity, may be found Hardness 8, being harder than calcareous in some specimens, and not in others. It occurs spar, but not so hard as apatite ; very brittle. in veins along with fluor spar at Beeralstone in Specific gravity 3.09 to 3.19; that of the speci- Devoushire, in Cumberland, in Saxony, and men, Leske, 0. 1613, is 3.154. Before the Norway. It has also been found at Kobola blow-pipe it generally decrepitates, gradually Poiana, in the district of Marmaros, in Hungary. loses its color and transparency, and melts, The whole of this genus is nearly irisoluble in without any flux, into a grayish-white glass. water. It does not effervesce with any acid, When two fragments are rubbed together, they except the concentrated vitriolic acid, and with become luminous in the dark. When gently that but feebly. The nitrous and marine acids, heated it phosphoresces with a blue and green in the common temperature of the atmosphere, light; but, by ignition, loses its phosphorescent are not absolutely inert with respect to it, but property. The violet-blue variety, from Nerts- scarcely dissolve it without decomposition. It chinsky, called chlorophane, when placed on is insoluble in the acetous. In a moderate heat glowing coals, does not decrepitate, but soon it decrepitates; and, if pulverised, phosphoresces, throws out a green light. It occurs principally particularly the blue or purple colored ; but, if in veins that traverse primitive, transition, and heated to redness, it will never afterwards phossometimes secondary rocks. It has been found phoresce. In a heat of 130° of Wedgwood, it only in four places in Scotland; but occurs melts in clay crucibles, or, but less perfectly, in much more abundantly in England, being found those of chalk, but on charcoal very imperfectly. in all the galena veins that traverse the coal for- By concentrated solar heat, or that given out by mation in Cumberland and Durham: in secon- pure air, it melts into a button which is genedary or floetz limestone in Derbyshire; and it is rally white and opaque when cold; if that heat the most common veinstone in the copper, tin, be long continued, it becomes less fusible. and lead veins, that traverse granite, clay-slate, FLUORIC Acid, in chemistry, is an acid &c., in Cornwall and Devonshire. It is also generally supposed among chemists, to be a frequent on the continent of Europe.

compound of an unknown radical fluorine and We need offer no apology for extracting the hydrogen. ch, at least, is the opinion exfollowing account of an experiment, by Dr. pressed by Dr. Henry, Dr. Thomson, and Sir Brewster, on the phosphorescence of a specimen H. Davy. of the blue foliated fluor: “When a thin slice Put one part of fuate of lime, i. e. fluor spar, was cut from this specimen, so as to be transpa- in coarse powder into a leaden or tin retort, and rent, it resembled a leaf with veins inclined to pour upon it two parts of sulphuric acid. Lute the ridge or central line which divided it into the retort to a leaden receiver, containing one two parts. The central line, and several of the part of water, and apply a gentle heat. The veins were colorless; while some of the veins Auoric acid gas disengaged will be absorbed by were of a deep amethyst color, and others of a the water, and form liquid Auoric acid, which pale amethyst color.'

must be kept in well-closed leaden or tin Upon placing this slice on a hot iron,' says bottles, or phials coated within with wax or Dr. Brewster, ' in order to examine its phospho- varnish. If the receiver be cooled with ice, and rescence, I was surprised to observe that the no water put in it, then the condensed acid is an phosphorescent matter was arranged in strata or intensely active liquid, first procured by M. Gay veins, parallel to those of the specimen, and Lussac. It has the appearance of sulphuric each stratum emitted a phosphoric light peculiar acid, but is much more volatile, and sends off to itself, and differing from that of the other white fumes when exposed to the moist air. Its strata either in color or intensity. Some of the specific gravity is only 1.0609. It must be veins discharged a purple light; others a yel- examined with great caution, for when applied lowish-green light; others a whitish light, and to the skin it instantly disorganises it, and proothers exhibited no phosphorescence at all. duces very painful wounds; and it instantly The most singular circumstance, however, was corrodes and disorganises glass, flints, &c. Its that the different strata of phosphoric light pre odor resembles muriatic acid, and its action served their boundaries sharp and well defined, upon all inflammable substances is very feeble, and were far more minute and numerous than as it does not afford any oxygen to them. With

ammonia, it forms a concrete body, and has no stances which are not rapidly dissolved or deaction upon platina, gold, silver, mercury, tin, composed by it, except metals, charcoal, lead, antimony, cobalt, nickel, or bismuth; but phosphorus, sulphur, and certain combinations it corrodes iron, arsenic, and manganese. It of chlorine. I attempted to make tubes of combines readily with water without depositing sulphur, of muriates of lead, and of copper any earth, and has an astringent acidulous taste. containing metallic wires, by which it might be A candle immersed in it is extinguished without electrised, but without success. I succeeded, any change in the color of "he Aame: it com- however, in boring a piece of horn silver in such bines with ammoniacal gas, forming a white a manner that I was able to cement a platina cloud : it dissolves camphor, and is taken up in wire into it by means of a spirit lamp; and by large quantity by oil of turpentine, to which it inverting this in a tray of platina, filled with communicates an orange color, and a pungent liquid fuoric acid, I contrived to submit the acid odor.

fluid to the agency of electricity in such a Fluoric acid gas volatilises silicious earth; manner, that, in successive experiments, it was which may be shown by decomposing Aluate of possible to collect any elastic fluid that might lime in a glass retort, and receiving the gas in a be produced. Operating in this way with a vesse! filled with water over mercury. Each very weak Voltaic power, and keeping the appabubble of the gas, which passes through the ratus cool by a freezing mixture, I ascertained mercury into the water, becomes immediately that the platina wire at the positive pole rapidly enveloped in a silicious crust, and leaves, as it corroded, and became covered with a chocolate ascends to the surface of the water, traces in the powder; gaseous matter separated at the negaform of tubes, which frequently decrease up- tive pole, which I could never obtain in sufficiwards, the bubble diminishing as the water dis- ent quantities to analyse with accuracy, but it solves it.

inflamed like hydrogen. No other inflammable The

gas, when disengaged in the glass retort, matter was produced when the acid was pure.' dissolves part of the silex of the retort, which it The following is Lavoisier's table of the comkeeps in an aeriform state. On coming into the binations of fuoric acid with the salifiable water, it abandons its caloric, and is converted bases, in the order of affinity. into fluoric acid, depositing at the same time

Names of the bases. Names of the neutral salts. the silex.

Fluate of lime, or fluor With the view of separating its hydrogen, Sir Lime

spar. H. Davy appl.ed the power of the great Voltaic


Barytes batteries of the Royal Institution to the liquid


Strontites. fuoric acid. "In this case,' says that eminent


Magnesia. chemist in his account of his experiments in the


Potash. Philosophical Transactions, 'gas appeared to be


Soda. produced from both the negative and positive


Ammoniac. surfaces; but it was probably only the undecom

Oxide of pounded acid rendered gaseous which was


Zinc. evolved at the positive surface; for during the


Manganese. operation the fluid became very hot, and speedily


Iron. diminished.'— In the course of these investiga


Lead. tions I made several attempts to detach hydro


Tin. gen from the liquid fuoric acid, by the agency


• Cobalt. of oxygen and chlorine. It was not decomposed when passed through a platina tube heat



Nickel. ed red-hot with chlorine, nor by being distilled


Arsenic. from salts containing abundance of oxygen, or Bismuth

Bismuth. those containing abundance of chlorine. By

Mercury the strict rules of chemical logic, therefore, we


Silver. ought to regard fuoric acid as a simple body,


Gold. as there is no evidence of its ever having been


Platina. decompounded; and nothing but analogy with

aud, by the dry way, the other acids has given rise to the assumption


Fluat of argil. of its being a compound.

The marvellous activity of this powerful acid The native Aluate of lime, the fluor spar already may be inferred from the following remarks of mentioned, is the most common. At the heat Sir H. Davy, from which also may be estimated, 130° of Wedgwood, it enters into fusion in a in some measure, the difficulty atiending refined clay crucible. It is not acted upon by the air, investigations on this extraordinary substance. and is insoluble in water. Concentrated sul

I undertook,' continues he,' the experiment phuric acid deprives it of the fluoric acid with of electrising pure liquid fluoric acid with con- effervescence, at the common temperature, but siderable interest, as it seemed to offer the most heat promotes its action. probable method of ascertaining its real nature; The affinity of the fluoric acid for siler has but considerable difficulties occurred in ex- already appeared. If the acid solution, obtained ecuting the process. The liquid fluoric acid im- hy keeping the solution of the acid in glass vesmediately destroys glass, and all animal and sels, be evaporated to dryness, the fluoric acid vegetable substances; it acts on all bodies con- may be disengaged from the solid salt remaining taining metallic oxides; and I know of no sub- either by the powerful acids, or by a strong heat;

and, if the solution be kept in a vessel that ad- attacked, but the feldt-spar was rendered opaque mits of a slow evaporation, sınall brilliant crys- and muddy, and covered with a white powder. tals, transparent, hard, and apparently of a Chrysoprase, an opal from Hungary, onyx, a rhomboidal figure, will form, as Bergman found, cornelian from Persia, agate, chalcedony, green on the bottom of the vessel, in the course of two Siberian jasper, and common fint, were etched years standing.

by it in twenty-four hours; the chrysoprase, Fluate of potash, soda, ammonia, or magnesia, nearly half a line deep, the onyx pretty deeply, the may be prepared by saturating their carbonates opal with the finest and most regular strokes, and with fluoric acid. Fluate of barytes is precipi- all the rest more or less irregularly. The uncotated by adding fluoric acid to the nitrate, or vered part of the brown flint had become white, muriate of barytes; and Auate of strontia is pre- but was still compact: water, alcohol, and other pared in a similar manner. Fluate of iron is liquids, rendered the whiteness invisible, hut, as obtained by dissolving the red oxide of iron in soon as the fint became dry, it appeared again. fuoric acid.

The same effect was produced on cornelian and Scheele observed, that the fuor acid united on a dark brown jasper, if the operation of the with alumina into a salt that could not be crys- acid was stopped as soon as it had whitened the tallised, but assumed a gelatinous form. Four- part exposed, without destroying its texture. A croy adds that the solution is always acid, astrin- piece of black flint with efflorescent white spots, gent, decomposable and precipitable by all the and partly covered with the common white earthy and alkaline bases.

crust, being exposed five days to the gas at a heat The only use to which fluoric acid has been of about 68° F. was reduced from 103 grains to applied is engraving on glass. It appears from 91, and rendered white throughout. Some parts Beckman that this was first practised by an artist of it were rendered friable. White Carrara of Nuremberg, in the year 1670, who prepared marble in twenty-four hours, at 77o, lost onehis etching liquor by digesting together nitrous thirtieth of its weight, but the shining surface of acid and finely powdered fluor spar for several its crystallised texture was distinguishable. hours on a warm sand-bath, and then using the Black marble was not affected, either in weight clear liquor as aquafortis is employed by the or color, and agate was not attacked. Transcopper-plate engravers. But the knowledge and parent foliated gypsum fell into white powder application of this liquor was confined to a few on its surface in a few hours; but this powder German artists, till, after the discoveries of was not soluble in dilute nitric acid,

-so that the Scheele and Priestley, the fluoric acid in a pure fuoric acid had not destroyed the combination state was used by various ingenious artists in of its principles; but deprived it of its water of England and France. Puymaurin found the crystallisation. A striated zeolite, weighing 102 liquid acid prepared according to Scheele's pro- grains, was rendered friable on its surface in cess to answer very well for this purpose in warm forty-eight hours, and weighed only eighty-five weather. The gaseous acid however is much grains and a balf. On being immersed in water, more efficacious. To engrave on glass, select a and then dried, it gained two grains and a half, piece of plate glass of the requisite size, cover it but did not recover its lustre. Barytes of a with hard engraver's wax, and with a needle or fibrous texture remained unchanged. A thin other suitable instrument trace the intended de- plate of Venetian talc, weighing 124 grains, was sign as in common etching, observing that every reduced to eighty-one grains in forty-eight hours, stroke passes quite through the way to the surface and had fallen into a soft powder, which floated of the glass. When the etching is completed, on water. See Chemistry. lay the plate with the engraved side downwards FLUO-SILIC Acid. If instead of being dison a frame, in a box lined with strong sheet lead tilled in metallic vessels, the mixture of fluor or thick tin foil, and place on the bottom of the spar and sulphuric acid be distilled in glass box a few leaden cups containing a mixture of vessels, little of the liquid will be obtained; but one part of very fine pulverised fluor spar and the glass will be corroded, and a peculiar gas two parts of sulphuric acid; then close the lid will be produced, which must be collected over of the box, and place it on a stove, or in any mercury. The best mode of procuring this is to other convenient situation where it may be ex mix the fluor spar with pounded glass or quartz; posed to as high a heat as it can bear without and, in this case, the retort may be preserved risking the melting of the wax : fuoric acid gas from corrosion, and the gas obtained in greater will be copiously disengaged, and in a short quantities. This gas, which is called silicated time (from one hour to three, according to cir- fluoric gas, is very heavy; 100 cubic inches of cumstances) the plate will be found sufficiently it weigh 110,77 grains. It is about forty-eight corroded.

times denser than hydrogen, and, when brought M. Kortum, of Warsaw, having found that some into contact with water, instantly deposits a pieces of glass were more easily acted upon than white gelatinous substance, which is hydrate of others, tried its effect on various stones. Rock silica and it produces white fumes when suffered crystal, ruby, sapphire, emerald, oriental garnet, to pass into the atmosphere. It is not affected amethyst, chrysolite, aventurine, girasol, a Saxon by any of the common combustibles; but when topaz, a Brasilian topaz burnt, and an opal, potassium is strongly heated in it, it takes fire being exposed to the fluoric gas at a temperature and burns with a deep red light; the gas is abof 122° F. were not acted upon. Diamond ex- sorbed, and a fawn-colored substance is formed, posed to the vapor on a common German stove which yields alkali to water with slight effervesfor four days, was unaffected. Of polished gra. "cence, and contains a combustible body. The inite, neither the quartz nor mica appeared to be washings afford potash, and a salt, from which

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