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food to its mouth with the other; feeds on fishes, roots, fruits and seeds. Flesh said to be good.

4. F. atra. Common coot. Five varieteis.
Front flesh-colour; bracelets greenish-
yellow; body blackish.
Black: wings white.

Entirely black; breast and belly waved
with ferruginous.

Brown: chin, belly and primary quilfeathers white; head spotted with white; upper mandible red.

White: head and wings with a few spots. Inhabits Europe, Asia, and America; fifteen inches long; frequents lakes and still rivers; and forms a floating nest among the rushes; lays numerous dirty-white eggs, sprinkled with minute, deep-rusty spots; the young, when first hatched, are very deformed; runs along the water, swims and dives dextrously; feeds on small insects, aquatic fishes, and seeds: in winter time often repairs to the sea.

5. F. aterrima. Greater coot. Front white; bracelets red; body blackish. Inhabits, like the last, our own country and other parts of Europe: scarcely differs from it but in increased magnitude and depth of black colour. FULIGINOUS. a. (fuliginosus, Lat.) Sooty; smoky (Howel).

FULIGO. fuligo, quasi fumiligo, from fumus, smoke.) Soot. Wood soot, fuligo ligni, or the condensed smoke from burning wood, has a pungent, bitter, and nauseous taste, and is resolved by chemical analysis into a volatile alkaline salt, an empyreumatic oil, a fixed alkali, and an insipid earth. The tincture prepared from this substance, tinctura fuliginis, is recommended as a powerful antispasmodic in hysterical affections.

FU'LIGO, in botany, a genus of the class cryptogamia, order fungi. Fungus with a cellular fibrous bark; the fibres penetrating in a reticulate manner through the seminal mass. Three species; one, F. septica, yellow and lanciniate, a native of our own country.

FU'LIMART. s. A kind of stinking ferret (Walton).

FULK (William,) a learned and eminent divine of the church of England, in the 16th century. He was patronised by the carl of Leicester, who in 1571 presented him to the living of Warley in Essex, and soon after to that of Diddington in Suffolk. He attended his patron when he went ambassador to

France; Pembroke-hall, and Margaret professor of divinity at Cambridge. His works are very numerous, levelled chiefly at the papists. The most considerable of them is his Comment on the Rhemish Testament. He died in 1589. FULL. a. (Fulle, Saxon.) 1. Replete; without vacuity; having no space void (Psalms). 2. Abounding in any quality good or bad (Sidney. Tillotson). 3. Stored with any thing; well supplied with any thing (Tickel). 4. Plump; saginated; fat (Wiseman). 5. Saturated; sated (Bacon). 6. Crowded with regard to the imagination or memory (Locke.)

and on his return was made master of

7. Large; great in effect (Arbuthnot). 8. Complete; such as that nothing further is desired or wanted (Hammond). 9. Complete without abatement (Swift). 10. Containing the whole matter; expressing much (Denham). 11.. Strong; not faint; not attenuated (Pope). 12. Mature; perfect (Bacon). 13. Spread to view in all dimensions (Addison).

FULL FLOWER. (flos plenus.) In bo• tany. When the corol is so multiplied as to exclude all the stamens. Polypetalous flowers are generally the object of plenitude. See LUXURIANS.

FULL MOON (plenilunium), that phasis of the moon, when the whole disk is illuminated; which is in the time of her opposition to the sun.

FULL. s. (from the adjective.) 1. Complete measure; freedom from deficiency (Clarendon). 2. The highest state or degree (Shakspeare). 3. The whole; the total (Shakspeare). 4. The state of being satiated (Jeremiah). 5. (Applied to the moon.) The time in which the moon makes a perfect orb (Bacon).

FULL. ad. 1. Without abatement (Milton). 2. With the whole effect (Dryden). 3. Exactly (Addison). 4. Directly (Dryden).

FULL-BLOWN. a. (full and blown.) 1. Spread to the utmost extent, as a perfect blossom (Denham). 2. Stretched by the wind to the utmost extent (Dryden).

FULL-BOTTOMED. a. (full and bottom) Having a large bottom (Guardian).

FULL-EARED. a. (full and ear). Having the heads full of grain (Denham). FULL-EY'ED. a. (full and eye.) Having large prominent eyes.

FULL-FED. a. (full and fed.) Sated; fat; saginated (Pope).

FULL-LA'DEN. a. (full and laden.) Laden till there can be no more added (Tillotson). FULL-SPREAD. a. (full and spread.) Spread to the utmost extent (Dryden) FULL-SU'MMED. a. (full and summed), Complete in all its parts (Howel).

J

To FULL. v. a. (fullo, Lat.) To cleanse cloth from its oil or grease. FU'LLAGE. s. (from full.) The money paid for fulling or cleansing cloth.

FULLAN, a country in the interior part of Africa, W. of the kingdom of Cushna Its boundaries have not been ascertained. FULLER. s. (fullo, Latin.) One whose trade is to cleanse and scour cloths.

FULLER (Nicholas), prebendary of Salisbury, and a learned English critic; who published in 1617 Miscellanea Theologica, in four books, and afterward two more of Miscellanea Sacra. He died in 1623; and there are some MSS. of his remaining in the Bodleian library, that show his great skill in Hebrew and philology.

FULLER (Dr. Thomas), a learned English divine, was born at Aldwinckle, near Oundle, in Northamptonshire, about the year 1608, and studied at Cambridge. He was chosen minister of St. Bennet's there; and, at about 23 years of age, his merit was so great, that he

was in consequence of it presented to a prebend in the church of Salisbury. He had also the living of Broad Windsor in Dorsetshire, and about 1640 became lecturer at the Savoy. It is said his memory was so tenacious and comprehensive, that he could make use of a sermon verbatim if he once heard it. He once undertook, in passing to and from Temple-bar to the Poultry, to tell at his return every sign as it stood in order on both sides of the way, repeating them either backwards or forwards; and this task he actually performed. He wrote, 1. A History of the Holy War. 2. The Church-history of Britain, in folio. 3. Andronicus, or the Unfortunate Politician, in 8vo. 4. A Pisgan-sight of Palestine. 5. A History of English Worthies; and other works. He died in August 1601, and was interred in the chancel of Cranford church in Middlesex, whither his body was attended by at least 200 of his brethren of the ministry. He was a learned, industrious, pious, moderate, and lively writer. His style however is exceedingly quaint, and he was too fond of punning. The doctor was a very corpulent man, and once as he was riding with a gentleman of the name of Sparrowhawk, he could not help cracking a joke upon his companion. "What is the difference (said he) between an owl and a sparrowhawk ?" "It is (answered the other) fuller in the head, fuller in the body, and fuller all over.”

FULLER'S EARTH. See ARGILLA

FULLONICA.

The greatest quantity and the finest quality of this earth is dug in the pits at Wavedon, near Woburn, Bedfordshire.

FULLER'S WEED. See DIPSACUS. FULLERY, the place where cloths, &c. undergo the operation of fulling.

:

FULLING, the art or act of cleansing, scouring, and pressing cloths, stuffs, and stockings, to render them stronger, closer, and firmer called also milling. Pliny (lib. vii. cap. 56.) asserts, that one Nicias, the son of Hermias, was the first inventor of the art of fulling: and it appears by an inscription, quoted by Sir G. Wheeler in his Travels through Greece, that this same Nicias was a governor in Greece in the time of the Romans. The fulling of cloths and other stuffs is performed by a kind of water-mill, thence called a fulling or scouring mill. These mills, except in what relates to the mill-stones and hopper, are much the same with corn-mills: and there are even some which serve indifferently for either use; corn being ground, and cloths fulled, by the inotion of the same wheel. Whence in some places, particularly in France, the fullers are called millers; grinding corn and milling stuffs at the same time.

The principal parts of the fulling-mill are: the wheel, with its trundle, which gives motion to the tree or spindle, whose teeth communicate it to the pestles or stampers, which are hereby raised and made to fall alternately, according as its teeth catch on or quit a kind of latch in the middle of each pestle. The

pestles and troughs are of wood; each trough having at least two, sometimes three pestles, at the discretion of the master, or according to the force of the stream of water. In these troughs are laid the cloths, stuffs, &c. intended to be fulled then, letting the current of water fall on the wheel, the pestles are successively let fall thereon, and by their weight and velocity stamp and press the stuffs very strongly, which by this means become thickened and condensed. In the course of the operation, they sometimes make use of urine, sometimes of fuller's earth, and sometimes of soap. To prepare the stuffs to receive the first impressions of the pestle, they are usually laid in urine; then in fuller's earth and water; and, lastly, in soap dissolved in hot water. Soap alone would do very well; but this is expensive: though fuller's earth, in the way of our dressing, is scarce inferior thereto; but then it must be well cleared of all stones and grittinesses, which are apt to make holes in the stuff. As to urine, many say it is prejudicial, and ought to be entirely discarded; not so much on account of its ill smell, as of its sharpness and saltness, which qualities are apt to render the stuffs dry and harsh. The true method of fulling with soap is delivered by Mons. Colinet, in an authentic memoir on that subject, supported by experiments made by order of the marquis de Louvois, then superintendant of the arts and manufactories of France; the substance of which we shall here subjoin.

The method of fulling cloths and woollen stuffs with soap is this:-A coloured cloth, of about 45 ells, is to be laid in the usual manner in the trough of a fulling-mill; without first soaking it in water, as is commonly practised in many places. To full this trough of cloth, 15 pounds of soap are required; one half of which is to be melted in two pails of river or spring water, made as hot as the hand can well bear it. This solution is to be poured by little and little upon the cloth, in proportion as it is laid in the trough: and thus it is to be fulled for at least two hours; after which, it is to be taken out and stretched. This done, the cloth is immediately returned into the same trough, without any new soap, and there fulled two hours more. Then taking it out, they wring it well, to express all the grease and filth. After the second fulling, the remainder of the soap is dissolved as in the former, and cast four different times on the cloth; remembering to take out the cloth every two hours, to stretch it, and undo the plaits and wrinkles it has acquired in the trough. When they perceive it sufficiently fulled, and brought to the quality and thickness required, they scour it for good in hot water, keeping it in the trough till it be quite clean. As to white cloths, since they full more easily and in less time than coloured ones, a third part of the soap may be spared.

The fulling of stockings, caps, &c. should be performed somewhat differently, viz. either with the feet or the hands, or a kind of wooden rack, either armed with teeth of the same matter, or else horses or bullock's teeth. The

ingredients made use of are, urine, green soap, white soap, and fuller's earth. But the urine also is reckoned prejudicial here. Woven stockings, &c. should be fulled with the soap alone: for those that are knit, earth may be used with the soap. Indeed it is common to full these kinds of works with the mill,after the usual manner of cloth, &c.; but that is too coarse and violent a manner, and apt to damage the work, unless it is very strong.

FU'LLINGMILL. s. (full and mill.) A mill where the water raises hammers which beat the cloth till it be cleansed (Mortimer). FULLY. ad. (from full.) 1. Without vacuity. 2. Completely; without lack (Hook.). FULMAR, in ornithology. See PROCEL

LARIA.

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To FU'LMINATE. v. a. To throw out as an object of terrour (Ayliffe).

FULMINATION. In chemistry, explosion or detonation, accompanied with a very considerable degree of sound. All these equally imply rapid decomposition with or without flame, and the intensity of sound alone distinguishes the idea of fulmination from those of detonation and explosion.

FULMINATING POWDER; a powder that explodes upon the application of certain degrees of bcat with instantaneous combustion, and prodigious sound. These are sometimes made with metals, and somtimes without.

Simple fulminating powder without any metallic substance is thus prepared: Take three parts of nitre, two of purified pearl-ash, and one of flowers of sulphur, mix the whole very accurately in an earthen mortar, and place it on a tile or plate before the fire till it is perfectly dry: then transfer it while hot into a ground stopper bottle, and it may be kept without injury for any length of time. In order to experience its effects, pour from ten to forty grains into an iron ladle, and place it over a slow fire: in a short time the powder becomes brown and acquires a pasty consistence; a blue lambent flame then appears on the surface, and in an instant after the whole explodes with a stunning noise and a slight momentary flash. If the mass be removed from the fire as soon as it is fused, and kept in a dry wellclosed vial, it may at any time be exploded by a spark, in which case it burns like gunpowder, but more rapidly and with greater detonation; but this effect cannot be produced on the unmelted powder how accurately soever the ingredients of it are mixed together. When fulminating powder is in fusion, but not heated to the degree necessary to produce the blue flame, a particle of ignited charcoal thrown upon it will occasion immediately a remarkably loud explosion.

It appears that the ingredients of this powder do not acquire their fulminating property till combined by fusion; in other words, till the pot ash of sulphur form sulphuret of potash: whence fulminating powder may also be made by mixing

sulphuret of potash with nitre, instead of by add. ing the sulphur and alkali separate.

In all these the cause of the detonation, or ful-
In sim-

mination, is not accurately understood.
ple fulminating powder, there is a very large
portion of elastic gass evolved; in fulminating
gold or silver a much smaller; yet the explosion
in the latter case is infinitely greater than that in
the former.

Fulminating gold.-Dissolve pure gold in nitromuriatic acid to saturation, and dilute the solution with three times its bulk of distilled water, and add to it gradually some pure ammonia, a yellow precipitate will be obtained, which must be repeatedly washed with distilled water, and dried on a chalk-stone or in a filter. When perfectly dry, it is called fulminating gold, and detonates by heat, as may be shewn by heating a few grains of it on the point of a knife over the candle.

Fulminating silver.-Dissolve fine silver in pale nitric acid, and precipitate the solution by lime water; decant the fluid, mix the precipitate with liquid ammonia, and stir it till it assumes a black

colour; then decant the fluid, and leave it in the open air to dry. This product is fulminating silver, which when once obtained cannot be touched without producing a violent explosion. It is the most dangerous preparation known, for the contact of fire is not necessary to cause it to detonate. It explodes by the mere touch. Its preparation is so hazardous, that it ought not to be attempted without a mask, with strong glass eyes, upon the face. No more than a single grain ought at any time to be tried as an experiment. This was invented by M. Berthollet. See ARGENTUM NATIVUM.

M. Chenevix has invented a fulminating silver not so dangerous as that just mentioned. It explodes only by a slight friction in contact with combustible bodies. It is thus prepared: diffuse a quantity of alumina through water, and let a current of oxygenated muriatic acid gass pass through it for some time. Then digest some phosphate of silver on the solution of the oxyge nated muriate of alumina, and evaporate it slowly. The product obtained will be a hyper-oxygenated muriate of silver, a single grain of which, in contact with two or three of sulphur, will explode violently with the slightest friction.

Fulminating mercury-The mercurial preparations which fulminate, when mixed with sulphur, and gradually exposed to a gentle heat, are well known to chemists: they were discovered, and have been fully described, by Mr. Bayen.

"MM. Brugnatelli and Van Mous have likewise produced fulminations by concussion, as well by nitrat of mercury and phosphorus as with phosphorus and most other nitrats. Cinnabar likewise is amongst the substances which, according to MM. Foureroy and Vauquelin, detonate by concussion with oxymuriat of potash.

"M. Ameilon had, according to M. Berthollet, observed, that the precipitate obtained from nitrat of mercury, by oxalic acid, fuses with a hissing noise.

"But mercury, and most if not all its oxyds, may, by treatment with nitric acid and alcohol, be converted into a whitish crystallized powder, possessing all the inflammable properties of gunpowder, as well as many peculiar to itself.

"I was led to this discovery (says Mr. Howard, the inventor) by a late assertion, that hydrogen

is the basis of the muriatic acid: it induced me to attempt to combine different substances with hydrogen and oxygen. With this view I mixed such substances with alcohol and nitric acid as might (by predisposing affinity) favour as well as attract an acid combination of the hydrogen of the one, and the oxygen of the other. The pure red oxyd of mercury appeared not unfit for this purpose; it was therefore intermixed with alcohol, and upon both nitric acid was affused. The acid did not act upon the alcohol so immediately as when these fluids are alone mixed together, but first gradually dissolved the oxide: however, after some minutes had elapsed, a smell of ether was perceptible, and a white dense smoke, much resembling that from the liquor fumans of Liba vius, was emitted with ebullition. The mixture then threw down a dark-coloured precipitate, which by degrees became nearly white. This precipitate I separated by filtration; and observing it to be crystallized in smaller acicular crystals, of a saline taste, and also finding a part of the mercury volatilized in the white fumes, I must acknowledge I was not altogether without hopes that muriatic acid had been formed, and united to the mercurial oxide; I therefore, for obvious reasons, poured sulphuric acid upon the dried crystalline mass, when a violent effervescence ensued, and, to my great astonishment, an explosion took place. The singularity of this explosion induced me to repeat the process several times; and finding that I always obtained the same kind of powder, I prepared a quantity of it, and was led to make the series of experiments which I shall have the honour to relate in this paper.

"I first attempted to make the mercurial powder fulminate by concussion; and for that purpose laid about a grain of it upon a cold anvil, and struck it with a hammer, likewise cold. It detonated slightly, not being, as I suppose, struck with a flat blow; for upon using three or four grains, a very stunning disagreeable noise was produced, and the faces both of the hammer and the anvil were much indented.

"Half a grain, or a grain, if quite dry, is as much as ought to be used on such an occasion. "The shock of an electrical battery, sent through five or six grains of the powder, produces a very similar effect. It seems, indeed, that a strong electrical shock generally acts on fulmiDating substances like the blow of a hammer. Messrs. Fourcroy and Vauquelin found this to be the case with all their mixtures of oxymuriate of potass.

"To ascertain at what temperature the mercurial powder explodes, two or three grains of it were floated on oil, in a capsule of leaf tin; the bulb of a Fahrenheit's thermometer was made just to touch the surface of the oil, which was then gradually heated till the power exploded, as the mercury of the thermometer reached the 368th degree.

laid open the upper part of the barrel, nearly from the touch-hole to the muzzle, and struck off the hand of the register, the surface of which was evenly indented, to the depth of 0.1 of an inch, as if it had received the impression of a punch.

"Desirous of comparing the strength of the mercurial compound with that of gunpowder, I made the following experiment in the presence of my friend Mr. Abernethy.

Finding that the powder could be fired by fint and steel, without a disagreeable noise, a common gunpowder proof, capable of containing eleven grains of fine gunpowder, was filled with it, and fired in the usual way: the report was sharp, but not loud. The person who held the instrument in his hand felt no recoil; but the explosion

"The instrument used in this experiment being familiarly known, it is therefore scarcely neces sary to describe it: suffice it to say, that it was of brass, mounted with a spring register, the move. able hand of which closed up the muzzle, to receive and graduate the violence of the explosion. The barrel was half an inch in caliber, and nearly half an inch thick, except where a spring of the lock impaired half its thickness.

"A gun belonging to Mr. Keir, an ingenious artist of Camden-Town, was next charged with seventeen grains of the mercurial powder, and a leaden bullet. A block of wood was placed at about eight yards from the muzzle to receive the ball, and the gun was fired by a fuse. No recoil seemed to have taken place, as the barrel was not moved from its position, although it was in no ways confined. The report was feeble: the bullet, Mr. Keir conceived, from the impression made upon the wood, had been projected with about half the force it would have been by an ordinary charge, or sixty-eight grains, of the best gunpowder. We therefore re-charged the gun with thirty-four grains of the mercurial powder; and as the great strength of the piece removed any apprehension of danger, Mr. Keir fired it from his shoulder, aiming at the same block of wood. The report was like the first, sharp, but not louder than might have been expected from a charge of gunpowder. Fortunately Mr. Kein was not hurt; but the gun was burst in an extraordinary manner. The breech was what is called patent one, of the best forged iron, consisting of a chamber 0.4 of an inch thick all round, and 0.4 of an inch in caliber; it was torn open and flawed in many directions, and the gold touch-hole driven out. The barrel into which the breech was screwed was 0.5 of an inch thick; it was split by a single crack three inches long, but this did not appear to me to be the immediate effect of the explosion. I think the screw of the breech, being suddenly enlarged, acted as a wedge upon the barrel. The ball missed the block of wood, and struck against a wall, which had already been the receptacle of so many bullets, that we could not satisfy ourselves about the impression made by this last.

"As it was pretty plain that no gun could confine a quantity of the mercurial powder sufficient to project a bullet with a greater force than an ordinary charge of gunpowder, I determined to try its comparative strength in another way. I procured two blocks of wood, very nearly of the same size and strength, and bored them with the same instrument to the same depth. The one was charged with half an ounce of the best Dart. ford gunpowder, and the other with half an ounce of the mercurial powder; both were alike buried in sand, and fired by a train communicating with the powders by a small touch-hole. The block containing the gunpowder was simply split into three pieces: that charged with the mercurial powder was burst in every direction, and the parts immediately contiguous to the powder were absolutely pounded, yet the whole hung together, whereas the block split by the gunpowder had its parts fairly separated. The sand surrounding the gunpowder was undoubtedly most disturbed: in short, the mercurial powder appeared to have

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acted with the greatest energy, but only within certain limits.

"The effects of the mercurial powder, in the last experiments, made me believe that it might be confined, during its explosion, in the centre of a bollow glass globe. Having therefore provided such a vessel, seven inches in diameter, and nearly half an inch thick, mounted with brass caps, and a stopcock, I placed ten grains of mercurial powder on thin paper, laid on iron wire, 149th of an inch thick, across the paper, through the midst of the powder, and, closing the paper, tied it fast at both extremities with silk to the wire. As the inclosed powder was now attached to the middle of the wire, each end of which was connected with the brass caps, the packet of powder became, by this disposition, fixed in the centre of the globe. Such a charge of an electrical battery was then sent along the wire, as a preliminary experiment (with Mr. Cuthbertson's electrometer) had shewn me would, by making the wire red hot, inflame the powder. The glass globe withstood the explosion, and of course retained whatever gasses were generated; its interior was thinly coated with quicksilver, in a very divided state. A bent glass tube was now screwed to the stop-cock of the brass cap, which being in troduced under a glass jar standing in the mercurial bath, the stop-cock was opened. Three cubical inches of air rushed out, and a fourth was set at liberty when the apparatus was removed to the water tub. The explosion being repeated, and the air all received over water, the quantity did not vary. To avoid an error from change of temperature, the glass globe was, both before and after the explosion, immersed in water of the same temperature. It appears, therefore, that the ten grains of powder produced four cubical inches only of air.

"To continue the comparison between the mercurial powder and gunpowder, ten grains of the best Dartford gunpowder were in a similar manner set fire to in the glass globe: it remained entire. The whole of the powder did not explode, for some complete grains were to be observed adhering to the interior surface of the glass. Little need be said of the nature of the gasses generated during the combustion of the gunpowder: they must have been carbonic acid gas, sulphureous acid gass, nitrogen gass, and (according to Lavoisier) perhaps hydrogen gass. As to the quantity of these, it is obvious that it could not be ascertained: because the two first were, at least in part, speedily absorbed by the alkali of the nitre, left pure after the decomposition of its mitric acid."

The following description will give the experimental philosopher a clear idea of the instrument used in this business.

The ball or globe of glass is nearly half an inch thick, and seven inches in diameter. It has two necks, on which are cemented two brass caps, each being perforated with a female screw, to receive the male ones; through the former a small hole is drilled; the latter is furnished with a perforated stud or shank. By means of a leather collar the neck can he air-tightly closed. When a portion of the powder is to be exploded, it must be placed on a piece of paper, and a small wire laid across the paper, through the midst of the powder: the paper being then closed, is to be tied at each end to the wire with a silken thread. One end of this wire is to be fastened to the end of the shank, and the screw inserted to half its

length iuto the brass cap; the other end of the wire, by means of a needle, is to be drawn through the hole. The screw being now fixed in its place, and the wire drawn tight, is to be secured by pushing the irregular wooden plug into the aperture of the screw, taking care to leave a passage for the air. The stop-cock is now to be screwed on. The glass tube is bent, that it may more conveniently be introduced under the receiver of a pneumatic apparatus.

"From some of the experiments in which the gunpowder proof and the gun were burst, it might be inferred, that the astonishing force of the mercurial powder is to be attributed to the rapidity of its combustion; and a train of several inches in length being consumed in a single flash, it is evident that its combustion must be rapid. But from other experiments it is plain that this force is restrained to a narrow limit, both because the block of wood charged with the mercurial powder was more shattered than that charged with the gunpowder, whilst the sand surrounding it was least disturbed, and likewise because the glass globe withstood the explosion of ten grains of the powder fixed in its centre; a charge I have twice found sufficient to destroy old pistol barrels, which were not injured by being fired when full of the best gunpowder. It also appears from the last experiment, that 10 grains of the powder produced by ignition four cubical inches only of air; and it is not to be supposed that the generation, however rapid, of four cubical inches of air, will alone account for the described force; neither caa it be accounted for by the formation of a little water, which, as will hereafter be shewn, happens at the same moment; the quantity formed from ten grains must be so trifling, that I cannot ascribe much force to the expansion of its vapour. The sudden vaporition of a part of the mercury seems to me a principal cause of this immense yet limited force; because its limitation may then be explained, as it is well known that mercury easily parts with caloric, and requires a temperature of 600 degrees of Fahrenheit, to be maintained in the vaporous state. That the mercury is really converted into vapour, by ignition of the powder, may be inferred from the thin coat of divided quicksilver, which, after the explosion in the glass globe, covered its interior surface; and likewise from the quicksilver with which a tallow candle, or a piece of gold, may be evenly coated, by being held at a small distance from the inflamed powder. These facts certainly render it more than probable, although they do not demonstrate that the mercury is volatilized; because it is not unlikely that many mercurial particles are mechanically impelled against the surface of the glass, the gold, and the tallow.

"As to the force of the dilated mercury, Mr. Baumé relates a remarkable instance of it, as follows:

Un alchymiste se présenta à Mr. Geoffroy, et l'assura qu'il avoit trouvé le moyen de fixer le mercure par une opération fort simple. Il fit construire six boîtes rondes en fer fort épais, qui entroient les unes dans les autres: la dernière étoit assujettie par deux cercles de fer qui se croisoient en angles droits. On avoit mis quelques livres de mercure dans la capacité de la première: on mit cet appareil dans un fourneau assez rempli de charbon pour faire rougir à blanc les boîtes de fer: mais, lorsque la chaleur eut pénétré suffisamment le mercure, les boîtes crevèrent, avec une telle explosion qu'il se fit un bruit épouvan

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