284 BALSAM COPAIVA 



These machines have proved even more accurate and rapid than those made for the 

 Bank ; and Professor Graham, the late Master, amongst the improvements introduced 

 by him into the system of the Mint, added to the number, and dispensed entirely with 

 the hand-weighing. It is said that the saving accruing from this change alone 

 amounts to nearly 2,000. per annum. See HYDBOSTATIC BALANCE ; WEIGHING MA- 

 CHINE. 



BAXiAS, BALLUS, or BAXiAXS RUBY. The names applied to the rose- 

 red and reddish-white varieties of spinel. See EUBY. 



BALE. A package of silk, lineu, or woollen, is so called. 



BALLESTEROSITE. A variety of iron pyrites found in Asturia. 



BALLISTIC PENDULUM. An instrument for measuring the force of cannon- 

 balls. The ballista was an instrument used by the ancients to throw darts, &c. The 

 ballistic pendulum derives its name from this : it consists of an iron cylinder, closed 

 at one end, suspended as a pendulum. A ball being fired into the open end, deflects 

 the pendulum according to the force of the blow received from the ball, thusmoasurl.i^ 

 its power. 



BALLOON 1 . In France, a quantity of glass. Of white glass, 25 bundles of six 

 plates each; of coloured glass, 12 bundles of three plates each, are called balloons. 

 Chemists call receivers and flasks of a spherical form balloons. 



BALLOONS. See AEROSTATION. 



BALL SODA, BLACK BALLS, or BLACK ASH. Crude carbonate of 

 soda, obtained in the manufacture of soda-ash. See SODA. 



BALM OF GILEAD. See BALSAM, MECCA. 



BALSAM. (Baume, Fr. ; Balsam, Ger.) A native compound of ethereal or 

 essential oils, with resin, and frequently benzoic acid. Most balsams have the con- 

 sistence of honey ; but a few are solid, or become so by keeping. They flow either 

 spontaneously, or by incisions made in trees and shrubs in tropical climates. They 

 have peculiar and sometimes powerful smells, aromatic hot tastes, but lose their 

 odoriferous properties by long exposure to the air. They are insoluble in water ; 

 soluble to a considerable degree, in ether ; and completely in alcohol. When distilled 

 with water, ethereal oil comes over, and resin remains in the retort. 



BALSAM, CANADA. See CANADA BALSAM. 



BALSAM; COPAIVA, or CAPIVI, or c APAXBA. (Baume de Copahu, Fr. ; 

 Kopaiva Balsam, Ger.) Capaiva balsam, balsam of copahu, or capivi, is obtained 

 from incisions made in the trunk of the Copaifera officinalis, a tree which grows in 

 Brazil and Cayenne. It is also very frequently obtained from the C. multijuga, 

 C. Langsdorfi, and C. Coriacea. It is pale yellow, semi-liquid, clear and transparent, 

 has a bitter, sharp, hot taste ; a penetrating disagreeable smell ; a specific gravity of 

 from 0-950 to 0-996. It dissolves in absolute alcohol, and partially in spirits of wine, 

 and forms with alkalis crystalline compounds. It consists of 45-59 ethereous oil, 

 52-75 of a yellow brittle resin, and 1*66 of a brown viscid resin. The oil contains no 

 oxygen, has a composition like that of oil of turpentine ; it dissolves caoutchouc 

 (according to Durand), but becomes oxidised, in the air, into a peculiar species of resin. 



This substance is extensively used in medicine. It was formerly often adulterated ; 

 some unctuous oil being mixed with it, but as this is easily discovered by its insolu- 

 bility in alcohol, castor-oil has since been used. The presence of this cheaper oil 

 may be detected, 1, by agitating the balsam with a solution of caustic soda, and 

 setting the mixture aside to repose, when the balsam will come to float clear on the 

 top, and leave a soapy thick magma of the oil below ; 2, when the balsam is boiled 

 with water, in a thin film for some hours, it will "become a brittle resin on cooling ; but 

 it will remain viscid if mixed with castor-oil ; 3, if a drop of the oil on white paper 

 be held over a lamp, at a proper distance, its volatile oil will evaporate, and leave the 

 brittle resin, without causing any stain around, which the presence of oil will pro- 

 duce ; 4, when throe drops of the balsam are poured into a watch-glass, alongside of one 

 drop of sulphuric acid, it becomes yellow at the point of contact, and altogether of a 

 saffron hue when stirred about with a glass rod ; but if sophisticated with castor-oil, 

 the mixture soon becomes nearly colourless, like white honey, though after some time 

 the acid blackens the whole in either case ; 5, if three parts in bulk of the balsam be 

 mixed with one of good water of ammonia (of 0-970 specific gravity) in a glass tube, 

 it will form a transparent solution if it be pure, but will form, a white liniment if it 

 contain castor-oil ; 6, if the balsam be triturated with a little of the common mag- 

 nesia alba, it will form a clear solution, from which acids dissolve out the magnesia, 

 and leave the oil transparent if it bo pure, but opaque if it be adulterated. When 

 turpentine is employed to falsify the balsam, the fraud is detected by the smell on 

 heating the compound. 



This balsam is used in the manufacture of some varieties of tracing paper ; and 

 many lacquers and varnishes have the balsam of copaiva as one of their constituents. 



