the action of fire on some pabulum or fuel, by which the minute parts thereof are put into a violent motion, and some of them assuming the nature of fire themselves, fly off in orbem, while the rest are dissipated in form of vapour or reduced to ashes. See Ignition.

Extraordinary Cases of Burning. We have instances of persons burnt by fire kindled within their own bodies. A woman at Paris, who used to drink brandy to excess, was one night reduced to ashes by a fire from within, all but her head and the ends of her fingers. Signora Corn Zangari, or, as others call her, Corn Bandi, an aged lady, of an unblemished life, near Cesena in Romagna, underwent the same fate in March 1731. She had retired in the evening to her chamber somewhat indisposed; and in the morning was found in the middle of the room reduced to ashes, all except her face, legs, skull, and three fingers. The stockings and shoes she had on were not burnt in the least. The ashes were light; and, on pressing between the fingers, vanished, leaving behind a grofs stinking moisture with which the floor was smeared; the walls and furniture of the room being covered with a moify cineritious foot, which had not only stained the linen in the chests, but had penetrated into the closet, as well as into the room overhead, the walls of which were moistened with the same viscous humour.—We have various other relations of persons burnt to death in this unaccountable manner.

Sig. Mondini, Bianchini, und Maffei, have written treatises expressly to account for the cause of so extraordinary an event: common fire it could not be, since this would likewise have burnt the bed and the room; besides that it would have required many hours, and a vast quantity of fuel, to reduce a human body to ashes; and, after all, a considerable part of the bones would have remained entire, as they were anciently found after the fiercest funeral fires. Some attribute the effect to a mine of sulphur under the house; others, to a miracle; while others suspect that art or villany had a hand in it. A philosopher of Verona maintains, that such a conflagration might have arisen from the inflammable matters wherewith the human body naturally abounds. Sig. Bianchini accounts for the conflagration of the lady above-mentioned, from her using a bath or lotion of camphorated spirit of wine when she found herself out of order. Maffei supposes it owing to lightning, but to lightning generated in her own body, agreeable to his doctrine, which is, That lightning does not proceed from the clouds, but is always produced in the place where it is seen and its effects perceived. We have have had a late attempt to establish the opinion, that these destroying internal fires are caused in the entrails of the body by inflamed effluvia of the blood; by juices and fermentation in the stomach; by the many combustible matters which abound in living bodies for the purposes of life; and, finally, by the fiery evaporation which exhale from the fettlings of spirit of wine, brandies, and other hot liquors, in the tunica villosa of the stomach and other adipose or fat membranes; within which those spirits engender a kind of camphor, which in the night-time, in sleep, by a full respiration, are put in a stronger motion, and are more apt to be set on fire. Others ascribe the cause of such persons being set on fire to lightning; and their burning so entirely, to the greater quantity of phosphorus and other combustible matter they contained.—For our own part, we can by no means pretend to explain the cause of such a phenomenon: but for the interests of humanity we wish it could be derived from something external to the human body; for if, to the calamities of human life already known, we superadd a suspicion that we may unexpectedly, and without the least warning, be consumed by an internal fire, the thought is too dreadful to be borne.

Brenning, in our old customs, denotes an infectious disease, got in the stews by conversing with lewd women, and supposed to be the same with what we now call the venereal disease.

In a manuscript of the vocation of John Bale to the bishopric of Ossory, written by himself, he speaks of Dr Hugh Wefton, who was dean of Windsor in 1556, but deprived by Cardinal Pole for adultery, thus: "At this day is lecherous Wefton, who is more practised in the arts of breech-burning, than all the whores of the stews. He not long ago burnt a beggar of St Botolph's parish." See Stews.

Antiquity, a way of disposing of the dead much practised by the ancient Greeks and Romans, and still retained by several nations in the East and West Indies. The antiquity of this custom rises as high as the Theban war, where we are told of the great solemnity accompanying this ceremony at the pyre of Menæceus and Archemorus, who were cotemporary with Jair the eighth judge of Israel. Homer abounds with funeral obsequies of this nature. In the inward regions of Asia the practice was of very ancient date, and the continuance long: for we are told, that, in the reign of Julian, the king of Chionia burnt his son's body, and deposited the ashes in a silver urn. Coeval almost with the first instances of this kind in the east, was the practice in the western parts of the world. The Herulians, the Getes, and the Thracians, had all along observed it; and its antiquity was as great with the Celts, Sarmatians, and other neighbouring nations. The origin of this custom seems to have been out of friendship to the deceased: their ashes were preserved as we preserve a lock of hair, a ring, or a seal, which had been the property of a deceased friend.

Kings were burnt in cloth made of the asbestos stone, that their ashes might be preserved pure from any mixture with the fuel and other matters thrown on the funeral pile. The same method is still observed with the princes of Tartary. Among the Greeks, the body was placed on the top of a pile, on which were thrown divers animals, and even slaves and captives, besides unguents and perfumes. In the funeral of Patroclus we find a number of sheep and oxen thrown in, then four horses, followed by two dogs, and lastly by 12 Trojan prisoners. The like is mentioned by Virgil in the funerals of his Trojans; where, besides oxen, swine, and all manner of cattle, we find eight youths condemned to the flames. The first thing was the fat of the beasts wherewith the body was covered, that it might consume the sooner: it being reckoned great felicity to be quickly reduced to ashes. For the like reason, where numbers were to be burnt at the same time, care was taken to mix with the rest some of humid constitutions, and therefore more easily to be inflamed. Thus we are assured by Plutarch and Macrobius, that for every ten men it was customary to put in one woman. Soldiers usually had their arms burnt with them. The garments worn by the living were also thrown on the pile, with other ornaments and presents; a piece of extravagance which the Athenians carried to so great a height, that some of their lawgivers were forced to restrain them, by severe penalties, from defrauding the living by their liberality to the dead.—In some cases, burning was expressly forbidden among the Romans, and even looked upon as the highest impiety. Thus infants, who died before the breeding of teeth, were interred unburnt in the ground, in a particular place set apart for this purpose, called sugrundarium. The like was practised with regard to those who had been struck dead with lightning, who were never to be burnt again. Some say that burning was denied to suicides.—The manner of burning among the Romans was not unlike that of the Greeks; the corpse, being brought out without the city, was carried directly to the place appointed for burning it; which, if it joined to the sepulchre, was called burying; if separate from it, burying; and there laid on the rogur or pyra, a pile of wood prepared on which to burn it, built in shape of an altar, but of different height according to the quality of the deceased. The wood used was commonly from such trees as contain most pitch or rosin; and if any other were used, they split it for the more easy catching fire: round the pile they let cypress trees, probably to hinder the noisome smell of the corpse. The body was not placed on the bare pile, but on the couch or bed wherein it lay. This done, the next of blood performed the ceremony of lighting the pile; which they did with a torch, turning their faces all the while the other way, as if it were done with reluctance. During the ceremony, decursions and games were celebrated; after which came the offegium, or gathering of the bones and ashes; also washing and anointing them, and repotting them in urns.

Burning, among surgeons, denotes the application of an actual cautery, that is, a red-hot iron instrument, to the part affected: otherwise denominated cauterization. The whole art of physic among the Japanese lies in the choice of places proper to be burnt: which are varied according to the disease. In the country of the Mogul, the colic is cured by an iron ring applied red-hot about the patient's navel. Certain it is, that some very extraordinary cures have been performed accidentally by burning. The following case is recorded in the Memoirs of the academy of sciences by M. Homberg. A woman of about 35 became subject to a head- Burning, which at times was so violent that it drove her out of her senses, making her sometimes stupid and foolish, at other times raving and furious. The seat of the pain was in the forehead, and over the eyes, which were inflamed, and looked violently red and sparkling; and the most violent fits of it were attended with nausea and vomiting. In the times of the fits, she could take no food; but out of them, had a very good stomach. Mr Homberg had in vain attempted her cure for three years with all kinds of medicines: only opium succeeded; and that but little, all its effect being only the taking off the pain for a few hours. The redness of her eyes was always the sign of an approaching fit. One night, feeling a fit coming on, she went to lie down upon the bed; but first walked up to the glass with the candle in her hand, to see how her eyes looked: in observing this, the candle fell fire to her cap: and as she was alone, her head was terribly burnt before the fire could be extinguished. Mr Homberg was sent for, and ordered bleeding and proper dressings: but it was perceived, that the expected fit this night never came on; the pain of the burning wore off by degrees; and the patient found herself from that hour cured of the headache, which had never returned in four years after, which was the time when the account was communicated. Another case, not less remarkable than the former, was communicated to Mr Homberg by a physician at Bruges. A woman, who for several years had her legs and thighs swelled in an extraordinary manner, found some relief from rubbing them before the fire with brandy every morning and evening. One evening the fire chanced to catch the brandy she had rubbed herself with, and slightly burnt her. She applied some brandy to her burn; and in the night all the water her legs and thighs were swelled with was entirely discharged by urine, and the swelling did not again return.

**Burning-Bush.** See **Bush.**

**Burning Glass,** a convex glass commonly spherical, which being exposed directly to the sun, collects all the rays falling thereon into a very small space called the focus; where wood or any other combustible matter being put, will be set on fire. The term burning-glass is also used to denote those concave mirrors, whether composed of glass quicksilvered, or of metallic matters, which burn by reflection, condensing the sun's rays into a focus similar to the former.

The use of burning-glasses appears to have been very ancient. Diodorus Siculus, Lucian, Dion, Zonaras, Galen, Anthemius, Euclidius, Tzetzes, and others, attest, that by means of them Archimedes set fire to the Roman fleet at the siege of Syracuse. Tzetzes is so particular in his account of this matter, that his description suggested to Kircher the method by which it was probably accomplished. That author says, that "Archimedes set fire to Marcellus's navy, by means of a burning glass composed of small square mirrors moving every way upon hinges; which, when placed in the sun's rays, directed them upon the Roman fleet, so as to reduce it to ashes at the distance of a bow shot."

A very particular testimony we have also from Anthemius of Lydia, who takes pains to prove the possibility of setting fire to a fleet, or any other combustible body, at such a distance.

That the ancients were also acquainted with the use of catoptric or refracting burning-glasses, appears from a passage in Aristophanes's comedy of The Clouds, which clearly treats of their effects. The author introduces Socrates as examining Strephades about the method he had discovered of getting clear of his debts. He replies, that "he thought of making use of a burning-glass which he had hitherto used in kindling his fire;" "for (says he) should they bring a writ against me, I'll immediately place my glass in the sun at some little distance from it, and set it on fire." Pliny and Lactantius have also spoken of glasses that burn by refraction. The former calls them balls or globes of glass or crystal, which, exposed to the sun, transmit a heat sufficient to set fire to cloth, or corrode the dead flesh of those patients who stand in need of caustics; and the latter, after Clemens Alexandrinus, takes notice that fire may be kindled by interposing glasses filled with water between the sun and the object, so as to transmit the rays to it.

It seems difficult to conceive how they should know such glasses would burn without knowing they would magnify, which it is granted they did not, till towards the close of the 13th century, when spectacles were first thought on. For as to those passages in Plautus which seem to intimate the knowledge of spectacles, M. de la Hire observes, they do not prove any such thing; and he solves this, by observing, that their burning-glasses being spheres, either solid or full of water, their foci would be one-fourth of their diameter distant from them. If then their diameter were supposed half a foot, which is the most we can allow, an object must be at an inch and a half distance to perceive it magnified; those at greater distances do not appear greater, but only more confused through the glass than out of it. It is no wonder, therefore, the magnifying property of convex glasses was unknown, and the burning one known. It is more wonderful there should be 300 years between the invention of spectacles and telescopes.

Among the ancients, the burning mirrors of Archimedes and Proclus are famous: the former we have already taken notice of; by the other, the navy of Vitellius besieging Byzantium, according to Zonaras, was burnt to ashes.

Among the moderns, the most remarkable burning mirrors are those of Settala, of Villette, of Tschirnhausen, of Buffon, of Trudaine, and of Parker.

Settala, canon of Padua, made a parabolic mirror, which, according to Schottus, burnt pieces of wood at the distance of 15 or 16 paces. The following things are noted of it in the *Acta Eruditorum.* 1. Green wood takes fire instantaneously, so as a strong wind cannot extinguish it. 2. Water boils immediately; and eggs in it are presently edible. 3. A mixture of tin and lead, three inches thick, drops presently; and iron and steel plate becomes red-hot presently, and a little after burns into holes. 4. Things not capable of melting, as flones, bricks, &c., become soon red-hot, like iron. 5. Slate becomes first white, then a black glass. 6. Tiles are converted into a yellow glass, and shells into a blackish yellow one. 7. A pumice stone, emitted from a volcano, melts into white glass; and, 8. A piece of crucible also vitrifies in eight minutes. 9. Bones are soon turned into an opaque glass, and earth into a black one. The breadth of this mirror is near three Leipic cells; its focus two cells from it; it is made of copper, and Burning, and its substance is not above double the thickness of the back of a knife.

Villette, a French artist of Lyons, made a large mirror, which was bought by Tavernier and presented to the king of Persia; a second, bought by the king of Denmark; a third, presented by the French king to the Royal Academy; a fourth has been in England, where it was publicly exposed. The effects hereof, as found by Dr Harris and Dr Desguliers, are, that a silver sixpence is melted in 7½", a King George's halfpenny in 16", and runs with a hole in 34". Tin melts in 3", cast iron in 16", slate in 3½"; a fossil shell calcines in 7"; a piece of Pompey's pillar at Alexandria vitrifies, the black part in 50", in the white in 54"; copper ore in 8"; bone calcines in 4"; vitrifies in 33¾". An emerald melts into a substance like a turquoise stone; a diamond weighing four grains loses ½ of its weight: the asbestos vitrifies; as all other bodies will do; if kept long enough in the focus; but when once vitrified, the mirror can go no farther with them. This mirror is 47 inches wide, and is ground to a sphere of 76 inches radius; so that its focus is about 38 inches from the vertex. Its substance is a composition of tin, copper, and tin-glass.

Every lens, whether convex, plano-convex, or convexo-convex, collects the sun's rays, dispersed over its convexity, into a point by refraction; and is therefore a burning glass. The most considerable of this kind is that made by M. de Tschirnhausen; the diameters of his lenses are three and four feet, the focus at the distance of 12 feet, and its diameter an inch and a half. To make the focus the more vivid, it is collected a second time by a second lens parallel to the first, and placed in that point where the diameter of the cone of rays formed by the first lens is equal to the diameter of the second; so that it receives them all; and the focus, from an inch and a half, is contracted into the space of eight lines, and its force increased proportionally.

This glass vitrifies tiles, flates, pumice-stones, &c., in a moment. It melts sulphur, pitch, and all resins, under water; the ashes of vegetables, woods, and other matters, are transmuted into glass; and every thing applied to its focus is either melted, turned into a calx, or into smoke. Tschirnhausen observes, that it succeeds best when the matter applied is laid on a hard charcoal well burnt.

Sir Isaac Newton presented a burning-glass to the royal society, consisting of seven concave glasses, so placed as that all their foci join in one physical point. Each glass is about 11 inches and a half in diameter: six of them are placed round the seventh, to which they are all contiguous; and they form a kind of segment of a sphere, whose subtense is about 34 inches and a half, and the central glass lies about an inch farther in than the rest. The common focus is about 22 inches and a half distant, and about an inch in diameter. This glass vitrifies brick or tile in 1", and melts gold in 30".

It would appear, however, that glass quicksilvered is a more proper material for burning glasses than metals; for the effects of that specimen wherewith Mr Macquer melted the platina seem to have been superior to those above mentioned, though the mirror itself was much smaller. The diameter of this glass was only 22 inches, and its focal distance 28. Black flint, when exposed to the focus, being powdered to prevent its crackling and flying about, and secured in a large piece of charcoal, bubbled up and ran into transparent glass in less than half a minute. Hessian crucibles, and glass-house pots, vitrified completely in three or four seconds. Forged iron smoked, boiled, and changed into a vitreous scoria as soon as it was exposed to the focus. The gypsum of Montmartre, when the flat sides of the plates or leaves of which it is composed were presented to the glass, did not show the least disposition to melt; but, on presenting a transverse section of it, or the edges of the plates, it melted in an instant, with a hissing noise, into a brownish yellow matter. Calcareous stones did not completely melt; but there was detached from them a circle more compact than the rest of the mass, and of the size of the focus; the separation of which seemed to be occasioned by the shrinking of the matter which had begun to enter into fusion. The white calx of antimony, commonly called diaphoretic antimony, melted better than the calcareous stones, and changed into an opaque pretty glossy substance like white enamel. It was observed, that the whitening of the calcareous stones and the antimonial calx was of great disadvantage to their fusion, by reason of their reflecting great part of the sun's rays; so that the subject could not undergo the full activity of the heat thrown upon it by the burning-glass. The case was the same with metallic bodies; which melted too much the more difficulty as they were more white and polished; and this difference was so remarkable, that in the focus of this mirror, so fusible a metal as silver, when its surface was polished, did not melt at all.

Plate CXXXI. fig. 1. represents M. Buffon's burning mirror, which he with great reason supposes to be of the same nature with that of Archimedes. It consists of a number of small mirrors of glass quicksilvered, all of which are held together by an iron frame. Each of these small mirrors is also moveable by a contrivance on the back part of the frame, so that their reflections may all coincide in one point. By this means they are capable of being accommodated to various heights of the sun, and to different distances. The adjusting them in this manner takes up a considerable time; but after they are so adjusted, the focus will continue unaltered for an hour or more.

Fig. 2. represents a contrivance of M. Buffon's for diminishing the thickness of very large refracting lenses. He observes, that in the large lenses of this kind, and which are most convenient for many purposes, the thickness of the glass in the middle is so great as very much to diminish their force. For this reason he proposes to form a burning-glass of concentric circular pieces of glass, each resting upon the other, as represented in the figure. His method is to divide the convex arch of the lens into three equal parts. Thus, suppose the diameter to be 26 inches, and the thickness in the middle to be three inches: By dividing the lens into three concentric circles, and laying the one over the other, the thickness of the middle piece needs be only one inch; at the same time that the lens will have the same convexity, and almost the same focal distance, as M. Trudaine, a French gentleman, constructed a burning lens on a new principle. It was composed of two circular segments of glass spears, each four feet in diameter, applied with their concave sides towards each other. The cavity was filled with spirit of wine, of which it contained 42 pints. It was presented by the maker to the royal academy of sciences, but was not long after broken by accident. The expense of constructing it amounted to about 1000l. sterling. After all, it does not appear that the effects of this lens were very great. Mr Magellan informs us, that it could only coagulate the particles of platinum in 20 minutes, while Mr Parker's lens entirely melted them in less than two.

A large burning lens, indeed, for the purpose of fusing and vitrifying such substances as resist the fires of ordinary furnaces, and especially for the application of heat in vacuo, and in other circumstances in which heat cannot be applied by any other means, has long been a desideratum among persons concerned in philosophical experiments: And it appears now to be in a great degree accomplished by Mr Parker. His lens is three feet in diameter, made of flint-glass, and which, when fixed in its frame, exposes a surface two feet eight inches and a half in the clear.

In the Elevation represented on Plate CXXXII, A is the lens of the diameter mentioned: thickness in the centre, three inches and one-fourth: weight, 212 pounds: length of the focus, six feet eight inches; diameter of ditto, one inch. B, a second lens, whose diameter in the frame is 16 inches, and shows in the clear 13 inches: thickness in the centre, one inch five-eighths: weight 21 pounds: length of focus 29 inches: diameter of ditto, three-eighths of an inch. When the two above lenses are compounded together, the length of the focus is five feet three inches: diameter of ditto, half an inch. C, a truncated cone, composed of 21 ribs of wood: at the larger end is fixed the great lens A; at the smaller extremity the lesser lens B: near the smaller end is also fixed a rack, D, passing through the pillar L, moveable by a pinion turning in the laid pillar, by means of the handle E, and thus giving a vertical motion to the machine. F, a bar of wood, fixed between the two lower ribs of the cone at G; having, within a chafed mortice in which it moves, an apparatus H, with the iron plate, I, fixed thereto; and this part turning on a ball and socket, K, a method is thereby obtained of placing the matter under experiment, so as to be acted upon by the focal rays in the most direct and powerful manner. LL, a strong mahogany frame, moving on castors, MM. Immediately under the table N are three friction wheels, by which the machine moves horizontally. O, a strong iron bow, in which the lens and the cone hang.

Section. a, The great lens marked A in the elevation. b, The frame which contains the lens. c, The small lens marked B. d, The frame which contains the small lens. e, The truncated cone, marked C. f, The bar on which the apparatus marked F moves. g, The iron plate marked I. h, The cone of rays formed by the refraction of the great lens a, and falling on the lens c. i, The cone of rays formed by the refraction of the lens c, Front-view. k, The great burning lens. l, The frame containing it. m, The strong iron bow in which it hangs.

From a great number of experiments made with this lens, in the presence of many scientific persons, the following are selected as specimens of its powers.

| Substances fused, with their weight and time of fusion. | Weight in Grams | Time in Seconds | |----------------------------------------------------------|----------------|----------------| | Gold, pure, | 20 | 3 | | Silver, do, | 20 | 4 | | Copper, do, | 33 | 20 | | Platina, do, | 10 | 3 | | Nickell, | 16 | 3 | | Bar iron, a cube, | 10 | 12 | | Cast iron, a cube, | 10 | 3 | | Steel, a cube, | 10 | 12 | | Scoria of wrought iron, | 12 | 2 | | Terra ponderosa or barytes, | 10 | 7 | | A topaz, or chrysolite, | 3 | 45 | | An oriental emerald, | 2 | 25 | | Crystal pebble, | 7 | 6 | | White agate, | 10 | 30 | | Flint, oriental, | 10 | 30 | | Rough cornelian, | 10 | 75 | | Jasper, | 10 | 25 | | Onyx, | 10 | 20 | | Garnet, | 10 | 17 | | White rhomboidal spar, | 10 | 60 | | Zeolites, | 10 | 23 | | Rotten stone, | 10 | 80 | | Common flate, | 10 | 2 | | Asbestos, | 10 | 10 | | Common lime-stone, | 10 | 55 | | Pumice-stone, | 10 | 24 | | Lava, | 10 | 7 | | Volcanic clay, | 10 | 60 | | Cornilli moor-stone, | 10 | 60 |

Burning Mountains. See Ætna, Hecla, Vesuvius, and Volcano, with the plates accompanying them.

Burning Springs. Of these there are many in different parts of the world; particularly one in Dauphiny near Grenoble; another near Hermannstadt in Transylvania; a third at Chermay, a village near Switzerland; a fourth in the canton of Friburg; and a fifth not far from the city of Cracow in Poland. There also is, or was, a famous spring of the same kind at Wigan in Lancashire, which, upon the approach of a lighted candle, would take fire and burn like spirit of wine for a whole day. But the most remarkable one of this kind, or at least that of which we have the most particular description, was discovered in 1711 at Brofely in Shropshire. The following account of this remarkable spring was given by the reverend Mr Mason, Woodwardian professor at Cambridge, dated February 18, 1746. "The well for four or five feet deep is fix or seven feet wide; within that is another hole of like depth dug in the clay, in the bottom whereof is placed a cylindric earthen vessel, of about four or five inches diameter at the mouth, having the bottom taken off, and the sides well fixed in the clay rammed..." Burning, rammed close about it. Within the pot is a brown Burnisher, water, thick as puddle, continually forced up with a violent motion beyond that of boiling water, and a rumbling hollow noise, rising or falling by fits five or six inches; but there was no appearance of any vapour rising, which perhaps might have been visible, had not the sun shone so bright. Upon putting a candle down at the end of a stick, at about a quarter of a yard distance, it took fire, darting and flashing after a very violent manner for about half a yard high, much in the manner of spirits in a lamp, but with great agitation. It was said, that a tea-kettle had been made to boil in about nine minutes time, and that it had been left burning for 48 hours without any sensible diminution. It was extinguished by putting a wet mop upon it; which must be kept there for a little time, otherwise it would not go out. Upon the removal of the mop there arises a sulphurous smoke lasting about a minute, and yet the water is very cold to the touch." In 1755, this well totally disappeared by the sinking of a coal-pit in its neighbourhood.

The cause of the inflammable property of such waters is, with great probability, supposed to be their mixture with petroleum, which is a very inflammable substance, and has the property of burning on the surface of water.

**Burning of Colours**, among painters. There are several colours that require burning; as,

First, Lamp-black, which is a colour of so greasy a nature, that, except it is burnt, it will require a long time to dry. The method of burning, or rather drying, lamp-black, is as follows: Put it into a crucible over a clear fire, letting it remain till it be red hot, or so near it that no manner of smoke arises from it.

Secondly, Umber, which if it be intended for colour for a horse, or to be a shadow for gold, then burning fits it for both these purposes. In order to burn umber, you must put it into the naked fire, in large lumps, and not take it out till it is thoroughly red hot; if you have a mind to be more curious, put it into a crucible, and keep it over the fire till it be red hot.

Ivory also must be burnt to make black, thus: Fill two crucibles with shavings of ivory, then clap their two mouths together, and bind them fast with an iron-wire, and lute the joints close with clay, salt, and horse-dung, well beaten together; then set it over the fire, covering it all over with coals: let it remain in the fire till you are sure that the matter enclosed is thoroughly red hot: then take it out of the fire; but do not open the crucibles till they are perfectly cold; for were they opened while hot, the matter would turn to ashes; and so it will be, if the joints are not luted close.

**Burnisher**, a round polished piece of steel serving to smooth and give a lustre to metals.

Of these there are different kinds of different figures, straight, crooked, &c. Half burnishers are used to folder silver, as well as to give a lustre.

Burnishers for gold and silver are commonly made of a dog's or wolf's tooth, set in the end of an iron or wooden handle. Of late, agates and pebbles have been introduced, which many prefer to the dog's tooth.

The burnishers used by engravers in copper, usually serve with one end to burnish, and with the other to scrape.

**Burnishing**, the art of smoothing or polishing a metallic body, by a brisk rubbing of it with a burnisher.

Book-binders burnish the edges of their books, by rubbing them with a dog's tooth.

**Burnley**, a town of Lancashire in England, situated in W. Long. 2° 5'. N. Lat. 51° 3'.