crustaceous and testaceous marine animals. It is said to be a poisonous fish. B. vetula, or ancient file-fish, is likewise denominated the old wife fish, a name which it is supposed to have obtained from the appearance of the mouth when viewed in front, as well as from the slightly murmuring noise which it utters when first taken. B. maculatus, spotted file-fish; is of an oval shape; its length is about eighteen or twenty inches, sometimes as much as two feet; colour pale violet; skin strongly marked into lozenge-shaped reticulations; first dorsal fin three-rayed: the first very strong; ventral spines rough, and but slightly projecting; tail somewhat convex in the middle of the outline, with falcated tops; whole body, dorsal and anal fin marked with numerous round blue spots. Native of the Indian and American seas. B. undulatus, or black file-fish, is a native of the Indian seas, observed first about the shores of Sumatra by the enterprizing and highly meritorious traveller Mungo Park. From the mouth to the base of the pectoral fins run three red lines, and the body is obliquely undulated by twelve lines of the same colour. See Plate II. Pisces, fig. 1. BALL, in the military art, comprehends all sorts of bullets for fire arms, from the cannon to the pistol. Cannon-balls are made of iron; musketballs, pistol-balls, &c. are of lead. The experiment has been tried of iron balls for pistols and fusees, but they are justly rejected, not only on account of their lightness, which prevents them from flying straight, but because they are apt to furrow the barrel of the pistol, &c.

jongleur, whose profession it was to follow the bard and sing his works. About a century since the word ballad began to imply a brief, simple tale, conveyed in three or four verses, set to a short and familiar air, in which sense it is now understood.

BALLANCE, or BALANCE, in mechanics, one of the simple powers which serves to find out the equality or difference of weight in heavy bodies. See MECHANICS.

BALLANCE of trade, a term applied to the money ballance to be paid by one nation trading and carrying on business with another. So far as the articles mutually exported and imported pay for each other, there is no balance; but on which ever side the exports fall short in their amount, that nation is said to have the ballance of trade against it. See TRADE.

BALLANCE, hydrostatical. See HYDRO

STATICS.

BALLANCE of a clock or watch. See CLOCK-WORK and WATCH-WORK.

BALLANCE, to, in sea-language, to contract a sail into a narrower compass, and the term is applied particularly to the mizen of a ship, and the main sail of those vessels in which it is extended by a boom. The operation of ballancing the mizen is performed by lowering the yard a little, then rolling up a small portion of the sail at the upper corner, and lashing it about one-fifth down towards the mast. A boom-sail is ballanced by rolling up a portion of the clue, or lower aftermost corner, and fastening it strongly to the boom.

sail upright, rendering her of a prodigious weight. The ballast is sometimes one quar ter, one-third, or one-half, according to the difference of the bulk of the ship. Flat vessels require the most ballast. Ships are said to be in ballast, when they have no other loading. Masters of vessels are obliged to declare the quantity of ballast they bear, and to unload it at certain places. They are prohibited unloading their ballast in havens, roads, &c. the neglect of which prohibition has ruined many excellent ports. All ships and vessels taking in ballast on the river Thames are bound to pay the corporation of the Trinity. house for every ton carried to any ship in the coal trade 18. and for every other British ship, 1s. 3d. For every ton carried to any foreign ship, 18. 7d. The Trinity-house employ men, and regulate them, and their lighters are to be marked. The art of bal

lasting, as it is called, consists in placing the centre of gravity, so as neither to be too high nor too low, too far forward nor too far aft, and that the surface of the water may nearly rise to the extreme breadth amidship, and thus the ship will be enabled to carry a good sail, incline but little, and ply well to the windward.

BALLET, in music, a theatrical representation of some tale or fable told in dance, or metrical action, accompanied with music. The artist who invents and superintends the rehearsal and peformance of the ballet is called the ballet-master.

BALLISTA, in antiquity, a military machine used by the ancients in besieging cities, to throw large stones, darts, and javelins.

It resembled our cross-bows, though much larger, and superior in force.

From this engine stones of a size not less than mill-stones were thrown with so great violence, as to dash whole houses in pieces at a blow. It is described thus: a round iron cylinder was fastened between two planks, from which reached a hollow square beam, placed crosswise, and fastened with cords, to which were added screws; at one end of this stood the engineer, who put a wooden shaft with a big head into the cavity of the beam: this done, two men bent the engine by drawing some wheels: when the top of the head was drawn to the utmost end of the cords, the shaft was driven out of the ballista, &c.

BALLOON, or BALLON, in a general sense, signifies any spherical hollow body, of whatever matter it be composed, or for whatever purposes it be designed.

Thus, with chemists, balloon denotes a round short-necked vessel, used to receive what is distilled by means of fire; in architecture, a round globe on the top of a pillar; and among engineers, a kind of bomb made of pasteboard, and played off in fire-works, either in the air or in the water, in imitation of a real bomb. Balloon, in the French paper trade, is a term for a quantity of paper, containing 24 reams. It is also the name of a sort of brigantine used in the kingdom of Siam.

BALLOON. See AEROSTATION.

BALLOTA, in botany, a genus of the Didynamia Gymnospermia class and order. Natural order of the Verticillatæ, or Labiatæ. Essential character: calyx salvershaped, five-toothed, ten-streaked: corolla upper-lip crenate, concave. There are six species. B. nigra is the black or stinking

horehound, a hairy plant, with an upright brownish stem, about two feet in height. It is a perennial plant, common in most parts of Europe, in waste places and hedges, flowering in July. It is recommended in hysterical cases. In Gothland it is an universal remedy for cattle; but the Swedish plant is probably not the same as ours. The European sorts, being common stinking weeds, are never introduced into gardens.

BALLS, or BALLETS, in heraldry, a frequent bearing in coats of arms, usually denominated according to their colours, bezants, plates, hurts, &c.

BALM, or BAUM, in botany. See ME

BALSAM, or NATIVE BALSAM, an oily, resinous, liquid substance, flowing either spontaneously, or by means of incision, from certain plants of sovereign virtue in

the cure of several disorders.

The term balsam, or balm, was originally confined to a thick fragrant juice, obtained from the amyris Gileadensis, and afterwards applied by chemists to all substances which possessed the same degree of consistence and a strong smell, whether natural or artificial. The word balsam originally implied a substance possessing a certain degree of fluidity: but now there are two classes of balsams; the one fluid, and the other solid and brittle. A balsam, then, is a substance which possesses the general properties of a resin; but which, when heated or digested in acids, yields a portion of benzoic acid. See BENZOIN.

Chemists, in general, have considered them as combinations of a resin with benzoic acid; but Mr. Hatchett has made it probable, that the acid is formed at the time of its separation. They are insoluble in water; but when boiled in that liquid often give out a portion of benzoic acid. Alcohol and ether dissolve them readily. The strong acids, likewise, dissolve them, and during the solution a portion of benzoic acid is separated. Nitric acid, in some cases, evolves likewise traces of prussic acid. The alkalies act upon them nearly as on the resins. They may be divided into two classes; namely, liquid and solid balsams.

1. Opobalsamum, or balm of Gilead.This balsam is obtained from the amyris Gileadensis, a tree which grows in Arabia, especially near Mecca. It is so much valued by the Turks, that it is seldom or never imported into Europe. We are, of course, ignorant of its composition. It is said to be at first turbid and white, and of a strong aromatic smell, and bitter, acrid, astringent taste; but by keeping, it be comes limpid and thin, and its colour changes first to green, then to yellow, and at last it assumes the colour of honey, and the consistence of turpentine. It is also very tenacious and glutinous, sticking to the fingers, and may be drawn into long threads. The mode of ascertaining the purity of this balsam at Cairo and Mecca is to drop it into a cup of clear cold water; if it remain in one place on the surface, it is of little or no value, but if it extend itself like a skin over the whole surface, (and this skin is even and almost transparent, and may be taken off the water with a hair,) it is of great worth. The balsam of Gilead principally comes from Arabia Petræa, from whence the Arabs carry it to Mecca for sale, during the stay of the caravans from Egypt and Turkey. It grows also in the Holy Land, but not without much culture and attention, whereas in Arabia it grows without cultivation. It is the produce of a species of the amyris, rising to the height of the pomegranate tree, to which it has a great resemblance, both in its branches and flowers. See AMYRIS. The balsam is obtained by incision during the summer months, flowing over in a viscous juice, called Opobalsamum. It is white when it comes from the tree, and changes first to a green, and afterwards to a gold colour.

2. Copaiva. This balsam is obtained from the Copaifera officinalis; a tree which grows in South America, and some of the West Indian islands. It exudes from incisions made in the trunk of the tree. The juice thus obtained is transparent, of a yellowish colour, an agreeable smell, a pungent taste, at first of the consistence of oil, but it gradually becomes as thick as honey. Its specific gravity is 0.950. When mixed with water and distilled, there comes over with the water a very large portion of vo

latile oil. The oil ceases to come over before all the water has passed into the receiver. The residuum, of course, consists of two substances; namely, the watery portion, and a greyish yellow substance, lying at the bottom of the vessel, which, on exposure to the air, dries, and becomes brittle and transparent. When heated, it melts, and possesses the characters of a resin. Nitric acid acts upon this balsam with considerable energy. When one part of the balsam is mixed with four parts of nitric acid and two parts of water, and heated, a yellowish solution is formed, similar to the original balsam, but darker. When distilled, there comes over with the liquid that passes into the receiver an apple-green oil, which lines the helm of the retort. The nature of the residue was not examined. When treated with sulphuric acid, it yields a portion of artificial tannin. Whether this balsam yields benzoic acid has not been ascertained. Its properties are rather against the probability of its doing so. Indeed it bears a striking resemblance to turpentine in many respects; and ought, along with it, to constitute a class of bodies interme diate between volatile oils and resins, to which the name of turpentines might be given.

3. Balsam of Tolu.-This substance is obtained from the Toluifera balsamum, a tree which grows in South America. The balsam flows from incisions made in the bark. It comes to Europe in small gourd shells. It is of a reddish brown colour and considerable consistence, and when exposed to the air it becomes solid and brittle. Its smell is fragrant, and continues so even after the balsam has become thick by age. When distilled with water, it yields very little volatile oil, but impregnates the water strongly with its taste and smell. A quantity of benzoic acid sublimes, if the distillation be continued. Mr. Hatchett found it soluble in the alkalies, like the rest of the balsams. When he dissolved it in the smallest possible quantity of lixivium of potash, it completely loses its own odour, and assumes a most fragrant smell, somewhat resembling that of the clove pink. "This smell," Mr. Hatchett observes, "is not fugitive, for it is still retained by a solution which was prepared in June, and has remained in an open glass during four months." When digested in sulphuric acid, a

considerable quantity of pure benzoic acid sublimes. When the solution of it in this acid is evaporated to dryness, and the resi

duum treated with alcol:ol, a portion of artificial tannin is obtained; the residual charcoal amounts to 0.54 of the original balsam. 4. Balsam of Peru is obtained from the Myroxylon Peruiferum. The tree is full of resin, and the balsam is obtained by boiling the twigs in water. It has the consistency of honey, a brown colour, an agreeable smell, and a hot acrid taste. When boiled with water for some time, the liquid separated by the filter reddens vegetable blues, and deposits crystals of benzoic acid on cooling. The water contains no other substance. When distilled with water, it yields a very small quantity of reddish limpid oil. A saturated solution of carbonate of soda forms with this balsam a thick mass. When diluted with water and heated, a portion is dissolyed. The solution, when saturated with sulphuric acid, deposits crystals of benzoic acid. One part of the balsam, treated with one part of potash dissolved in four parts of water, formed an opaque solution, which gradually separated into two portions: the uppermost, a clear oil, with some grey flakes at its lower surface; the undermost, a dark brownish red opaque solution. This last solution, when saturated with sulphuric acid, let fall a resinous-like substance, dissolved by boiling, while benzoic acid crystallized. Nitric acid acts upon the balsam with energy, and gives it an orange yellow colour, when assisted by heat. When distilled with a sufficient quantity of this acid diluted, the liquid in the receiver smells of bitter almonds. When this balsam is treated with sulphuric acid, artificial tannin is also formed, and the residual charcoal amounts to no less than 0.64 of the original weight of the balsam.

5. Styrax. This is a semifluid juice, said to be obtained from the Styrace officinale, a tree which grows in Virginia, Mexico, and some other parts of America. It is prepared in the island Cobrass, in the Red Sea, from the bark of a tree called rosa mallos by the natives, and considered by botanists as the same with the American species. The bark of this tree is boiled in salt water to the consistence of birdlime, and then put into casks. Bouillon la Grange has published an account of its properties. Its colour is greenish, its taste aromatic, and its smell agreeable. It is easily volatilized by heat. When treated with water benzoic acid is dissolved. It is totally soluble in alcohol, except the impurities. When exposed to the air, it becomes hard

1. Benzoin.-This substance is the produce of the styrax benzoe, a tree which grows in Sumatra, &c. and which has been described by Dr. Dryander. Benzoin is obtained from this tree by incision; a tree yielding three or four pounds. It is a solid brittle substance, sometimes in the form of yellowish white tears, joined together by a brown substance, and sometimes in the form of a brown substance, not unlike common rosin. It has a very agreeable smell, which is increased by heating the benzoin. It has little taste. Its specific gravity is 1.092. Alcohol dissolves it when assisted by a gentle heat, and forms a deep yellow solution inclining to reddish brown. When this solution is diluted with water, the benzoin precipitates in the form of a white powder. It is precipitated also by muriatic and acetic acids, but not by the alkalies. A few drops of sulphuric acid likewise precipitate the benzoin; but an additional quantity redissolves it, and forms a liquid of the colour of port wine. Nitric acid acts with violence on benzoin, and converts it into an orangecoloured mass. When assisted by heat the acid dissolves the benzoin; and as the solution cools, crystals of benzoic acid gradually separate. Mr. Hatchett ascertained that by this process a quantity of artificial tannin is formed. Sulphuric acid dissolves benzoin, while benzoic acid sublimes; the solution is at first a deep red. By continuing the digestion, a portion of artificial tannen is formed, and the charcoal evolved amounts to 0.48 of the benzoin dissolved. Acetic acid dissolves benzoin without the assistance of heat. When heat is applied, the solution, as it cools, becomes turbid; owing to the separation of benzoic acid. Benzoin is dissolved by a boiling lixivium of the fixed alkalis; a dark brown solution is formed, which becomes turbid after some days' exposure to the air. Ammonia likewise dissolves benzoin sparingly.

2. Storax. This is the most fragrant of all the balsams, and is obtained from the