BAL 



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 4 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 repre- 

 sentation of some tale or fable, told in 

 dance, or metrical action, accompanied 

 with music. The artist who invents and 

 superintends the rehearsal and perform- 

 ance of the ballet is called the ballet- 

 master. 



BALISTA, in antiquity, a military ma- 

 chine, 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 

 Jess than mill-stones were thrown with so 

 great a violence, as to dash whole houses 

 in pieces at a blow. It is described thus : 

 around iron cylinder was fastened be- 

 tween 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 en- 

 gineer, 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 

 balista, &c. 



BALLOON, or BALON, 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 re- 

 ceive 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. Bal- 

 loon, 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 

 Didynarnia Gymnospermia class and or- 

 der. Natural order of the Verticillatx, 

 or Labiatse. Essential character: calyx 

 salver-shaped, five-toothed, ten-streaked: 

 corolla upper-lip crenate, concave. There 

 are six species. B. Nigva is the black or 



BAL 



stinking horehound, a hairy plant, with 

 an upright brownish stem, about two feet 

 in height. It is a perennial plant, com- 

 mon in most parts of Europe, in waste 

 places and hedges, flowering in July. II 

 is recommended in hysterical cases. In 

 Gothland it is an universal remedy for cat- 

 tle ; 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 fre- 

 quent bearing in coats of arms, usually 

 denominated, according to their colours, 

 bezants, plates, hurts, &c. 



BALM, or BAUM, in botany. See Me- 



LISSA. 



BALNEUM, a term used by chemists 

 to signify a vessel filled with some matter, 

 as sand, water, or the like, in which ano- 

 ther is placed that requires a more gentle 

 heat than the naked fire. 



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 origin- 

 ally confined to a thick fragrant juice, ob- 

 tained from the amyris Gileadensis, and 

 afterwards applied by chemists to all sub- 

 stances which possessed the same degree 

 of consistence and a strong smell, whe- 

 ther natural or artificial. The word bal- 

 sam originally implied a substance pos- 

 sessing 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 pos- 

 sesses 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 ben- 

 zoic acid ; but Mr. Hatchet has made it 

 probable, that the acid is formed at the 

 time of its separation. They are insolu- 

 ble 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, dis- 

 solve them, and during the solution, a por- 

 tion 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. 



Liquid balsams. The liquid balsams 

 at present known are five in number; 

 namely, 



