BORACIC ACID, or BORIC ACID (from uborax*), a compound of boron with oxygen and hydrogen, having the formula H.B0,„ and possessing feebly acid properties. It occurs free in nature in an impure state in the crater of Vulcano, one of the Lipari islands, and in the crater of Stromboli. It is also found plentifully in Tuscany, where it issues from fissures in the soil, together with sulphurous exhalations, ammonia and other substances. On account of its havingbeen ob tained at Sasso, the acid is called by mineral ogists Sassolite. In the United States the fumes of boracic acid are found in emanations from fissures in Nevada and California. They are also found in Nova Scotia. In South America at many localities along the western coasts boracic acid occurs in immense quanti ties as boronatrocalcite, particularly in the great lagoons covering 2,000,000 acres near Ma ncunga. Concentrates of this deposit are be ing regularly shipped to England. The prin cipal supply of boracic acid is obtained from Tuscany, the exhalations above referred to be ing passed through water which absorbs the acid. The preparation of boracic acid from these aqueous solutions is an interesting proc ess on account of the natural obstacles which have to be surmounted. The apparently sim ple operation of concentrating the solution, so as to obtain the acid by crystallization, in real ity involves great practical difficulties, because in Tuscany the fuel supply is limited. This drawback has been overcome by utilizing the volcanic heat of the district to concentrate the solution. Around the cracks in the soil (called efumaroless or asoffionP), from which the steam containing the acid issues, and enclosing the small lakes or lagoons' in which it con denses, brick tanks are built on different levels, but communicating with each other. These are supplied with cold water, in which the steam is further condensed. When the water in the tanks is sufficiently saturated, it is run off into a deep vessel, where it is allowed to stand until the black mud mechanically sus pended in it falls to the bottom, and then the clear fluid is run into a series of shallow evaporating pans of lead. These pans are heated by steam from the soffioni, the steam being made to pass under them by a system of flues. As the evaporation proceeds the
fluid becomes richer in boracic acid, and when it attains a certain specific gravity, it is passed into a deep vat, where it is allowed to cool. Boracic acid then crystallizes but. The first crop of crystals is quite impure, but it is im proved by re-crystallization, and the second crop as thus obtained is packed in casks and exported. Commercial boracic acid sometimes contains as much as 25 per cent of foreign matter, consisting largely of clay, salts of cal cium and magnesium, and sulphates and other salts of the alkalis. About 2,000 tons of crude boracic acid are exported from Tuscany per annum. The South American product, con taining 55 to 60 per cent of boracic acid, has become a serious competitor of the Italian product in the markets of Europe. In the American market California's large production of colemanite (calcium borate) is an import ant factor. Persia has also recently become a source of boracic acid of excellent quality. Boracic acid is also prepared artificially by decomposing a hot solution of borax with sulphuric acid. The proportions are three parts of borax in 12 parts of hot water, and one part of sulphuric acid. The boracic acid separates out upon cooling. Boracic acid is a white, lustrous substance, of soapy feel, slightly soluble in cold water and considerably more soluble in hot water. It possesses strong anti septic properties, and is used as a preservative for meat. It is also used for glazing porce lain, and in the manufacture of certain kinds of glass. Boracic acid forms salts called Thoraces' with various metallic bases, of which borax is the most important. See BORON.
In medicine, boracic acid is used very widely. It is a mild antiseptic, and its solutions are use ful for cleansing the eyes, nose, mouth, bladder, etc. It forms with aromatic oils the basis of most mouth washes and nasal sprays. Boracic acid is also very useful in the nursery for keeping rubber nipples free from bacteria, and it is of great service in washing out nursing bottles, babies' mouths and eyes, and the mother's nipples while nursing. Large doses, however, may prove poisonous.