BORAVIC ACID is found native (1) in the steam or vapor which rises from certain volcanic rocks in Tuscany, and (2) as a saline incrustation in the crater of a mountain in the island Volcano, which is situated 12 rn. n. of Sicily. This crater is about 700 ft. deep, the sides lined with a crust of B. A. about half an inch thick, and is sufficient to yield an annual supply of 2000 tons. B. A. also occurs in combination in borax (q.v.), datholite (q.v.), boracite, and other minerals, and to a very minute extent in trap-rocks generally. The Tuscan supply of B. A. may be regarded as the most important, and its collection takes place over an area of about 30 miles. The plan pursued is to form a series of caldrons-100 to 1000 ft. in diameter, and 7 to 20 ft. deep—partly by excava tion, and partly by building, in the side of the volcanic mountain where the steam and B. A. vapors are issuing from fissures, and divert the course of a mountain stream, so that at pleasure the caldrons, or lagoons, may be supplied with water. 'As the volcanic vapors—called suftioni—gurgle through the water contained in the lagoons, the B. A. is arrested by the water, which becomes impregnated with it. The liquid is passed from one lagoon to another, then on to settling vats and flat-bottomed evaporating pans, till it becomes so concentrated that on cooling, impure crystals of B. A. separate. In this
condition it is sent to Eugland and other countries. The appearance of the surface of the ground, from which thousands of jets of steam are constantly issuing. is very striking; and the name given to one of the principal mountains, gonte rerboli (Mons Cerberi), denotes the feeling of awe with which the peasantry regarded the district as the entrance to the lower regions. Native B. A. is employed as a source of borax (q.v.) and contains about three fourths of its weight of true B. A., accompanied by one fourth of water and impurities. In a pure condition, B. A. may be prepared by dissolving 40 parts of borax (Na0,2B03) in 100 of water, and acting thereon by 25 parts of hydro chloric acid (11C1), which removes the soda, forming chloride of sodium (N'aC1) and water (I1O), and on cooling the mixture, the B. A. (BO,) crystallizes out. On re-solution in water and re-crystallization, it is obtained in pure white feathery crystals. B. A. Is used in the arts as a flux, as an ingredient in the glaze employed in pottery; and the wicks of stearine and composite candles are treated whit it, so that when the candle is burning, the end of the wick when it gets long may fuse and fall to the side, where it can be burned away. The exportation of B. A. from the Tuscan logoons exceeds 8,000,000 lbs, annually.