Page:The American Cyclopædia (1879) Volume II.djvu/565

 BENZOIN 545 tnre of about 302 F., the acid which exists ready formed in it is expelled, and may be con- densed in suitable receivers. Mohr's plan of conducting the sublimation is the simplest and best. His method is to place the gum in a shallow iron pan, which is covered with a sheet of filtering paper, over which a cone or hat of writing paper is fastened; on applying a regulated sand heat, the acid is decomposed, and the benzoic acid is converted into vapors ; it passes through the bibulous paper, and rises into the chamber formed by the paper cone, where it is condensed, and is prevented from falling back into the pan beneath by the inter- posed sheet of filtering paper. This method of sublimation is applicable in many other cases of a similar kind, as for example in the manu- facture of pyrogallic acid. The resins of tolu and benzoin, when treated with boiling nitric acid, yield an amorphous form of benzoic acid, colored yellow with a resinous matter which accompanies it into its salts, and hinders them from crystallizing. Balsam of tolu often yields nearly half its weight of this acid. This res- inous acid is completely soluble in boiling water. When this form of the acid is exposed to the sun's rays, it becomes covered with white crystals of pure benzoic acid ; and when sublimed, the ordinary crystalline acid is ob- tained. Benzoic acid is now prepared arti- ficially on a large scale from naphthaline and from hippuric acid, and is employed in the treatment of tobacco, as a mordant in calico printing, and especially in the production of aniline colors. Benzoic acid assumes the form of white, glistening, extremely light, flexible needles, which usually have an agreeable aro- matic odor and a hot bitterish taste. The odor, however, is not due to the acid, but to the presence of a trace of essential oil which accompanies the acid during the sublimation. Benzoic acid melts at 248 F. (120 0.) ; it sub- limes at 293 F. (145 0.), and boils at 462 F. (239 0.). Its vapors are acrid and irritating; when kindled in the open air, they burn with a smoky flame. The acid requires about 200 parts of cold water, and 25 of boiling water, for its solution ; but it is readily dissolved by alcohol and by ether. Benzoic acid yields a series of salts called benzoates, mostly soluble in water. The benzoate of ammonia is some- times used as a means of separating iron from nickel and cobalt. When prepared in the usual way by sublimation, benzoic acid contains a portion of the volatile oil. It is used in a few officinal preparations, especially in campho- rated tincture of opium. When given inter- nally, it is excreted by the urine, which it ren- ders acid, in the form of hippuric acid. It has been employed as a local haemostatic, though without proved utility. I.KV/OI V (Malay, kam.inian), the gum benja- min of commerce, an odorous resin extracted from the styrax benzoin, a tree which attains a considerable height, and is the peculiar pro- duct of Bencoolen, Batak, and Palembang ter- ritories, in Sumatra, and Brunai territory in Borneo. The tree is cultivated and raised from the small brown nut which it produces. When the plant has attained its fourth year and its stem has a diameter of eight inches on the E. coast of Sumatra, and six years and ten inches diameter on the W. coast, it begins to yield its best sap, which flows from the bark, and which is obtained by making an incision therein near the ground. That obtained during the first two years after tapping is of a creamy or light saffron tint, and is soft and fragrant ; for two or three years more it produces an inferior quality, of reddish hue, and harder than the best ; after this time the sap ceases to flow, the tree is cut down, and a very inferior resin is obtained by scraping the inner surface of the bark and the stem. From the Batak country it is brought to the markets on the W. coast of Sumatra in cakes called tampany, of different weights, and these cakes constitute the chief currency of the Bataks, who do not make use of coined money. The ben- zoin obtained in Pa- lembang territory is mainly collected by wild tribes in the lowest state of civi- lization, the Kubu in the Kawas and Ba- tang-Lekoh districts, and the Kumring fur- ther south. The Pa- lembang resin is gen- erally of an inferior quality, being mostly spontaneous exuda- Styra* benzoin. tions of wild trees - collected by these wild tribes. The resin is used as an incense in Greek and Roman Catholic churches. It is sometimes employed in medicine, being consid- ered a valuable expectorant and stimulant, and still more in perfumery. The odor of the best resin somewhat resembles that of the vanilla bean. Being soluble in spirits, and not in water, it is erroneously called a gum. Its density varies according to quality, from 1'063 to 1'092. Be- sides benzoic and cinnamic acid and a small quantity of essential oil, it contains three differ- ent kinds of resins, which have not yet been employed in the arts. It is used in several kinds of fine varnishes and lacquer work, on canes and snuff-boxes, which emit a faint vanilla odor when warmed with the hand. Benzoin is supposed by some writers to be the malabathrum of the ancients. Pliny and Dios- corides describe it very accurately ; and men- tion is made in the Periplus of the Erythraean sea of malabathrum, an article of commerce on the Malabar coast, said to be brought from a country farther east. Importations into the United States are prohibited unless the drug