Page:The New International Encyclopædia 1st ed. v. 02.djvu/873

BENTZON. vellc Anglctcrrc: yolcn de Voyarjc (1809). Mme. Bentzoii lins also translated several works by Diekciis, Bret Harte, Ouida, AKlrich, and other Knglish and American novelists.

BENUE, ben'wi', or BINUE. An important river of West Central Al'rira, and the largest tributary of the Niger (Map: Africa, E 4). it rises in southern Adamawa, in about latitude 7° 30' N., and longitude 13° 45' E. It flows gen- erally westward, and after a course of about 000 miles, joins the Niger 300 miles from the coast, in about latitude 8° N. Its width in its lower course varies from aboxit IGOO to 3200 feet, and its navigable length exceeds GOO miles during the wet season ; but during the dry season, Janu- sry to May, it is very shallow. Its chief tributaries are the IMajo Kebbi, Gongola, Ka- dera, Tarabba, and Faro. The Benue River was known to Europeans as early as 1831, and was then supposed to be connected with Lake Chad. In 1851 it was partially explored by Barth, who made an investigation of its iipix^r stream and exploded the theory of its be- ing connected with Lake Chad. In 1854 another expedition under Baikie explored the river as far as Dulti. about 350 miles above its conflu- ence with the Niger. In 1870 the explorer Rob- ert Hegel journeyed along the Benue through its entire navigable length and explored some of its tributaries. The expedition of Mizon. in 1892, made our knowledge of the river very com- plete. By an agreement between Germany and Great Britain the freedom of navigation on the Benue has been guaranteed.

BENVO'LIO. A character in Shakespeare's liomco and Juliet, a friend of Romeo. Mereutio describes him aptly in Act iii.. Scene 1.

BEN'WELL AND FEN'HAM. A munici- pality in Nortluunljerlaiul. England, on the Tyne, 2 '2 miles west of Newcastle. Coal -mining is the leading industry. Population, in 1891, 10,500; in 1901. 18.350."

BENZAL'DEHYDE. See Almonds, Vola- tile UlL OF.

BENZAYDA, ben-ziii'di'i. The heroic daugh- ter of the Sultan in Dryden's The Conquest of Granada. She loves the son of her father's mor- tal enemy, and follows liim through all the horrors of the war.

BEN'ZENE, or BEN'ZOL (for derivation see Be.vzoin ), CJL,. One of the most important of the compounds of carbon. Large quantities of it are industrially converted into nitrobenzene, from which, in turn, all of the aniline of com- merce is manufactured. The luminosity of a coal- gas flame is largely due to the presence of con- siderable quantities of benzene in the gas. Be- sides, benzene is an excellent solvent for fats, resins, iodine, and other substances', and is much used for cleaning purposes. The importance of benzene in pure chemistry is due to the fact that a very large number of substances are derived from it, the derivatives constituting the so-called aromatic compounds. Benzene may be obtained in a variety of ways; it is produced by passing the vapors of ordinary alcohol, ether, and many other organic substances through a tube heated to redness ; it is one of the constituents of the tar obtained by heating wood, peat, and shale out of contact with air, etc. Faradaj' first dis- covered it (1825) in oil-gas, and in 1845 Hof- uiann found it in coal-tar, from whieh all the benzene of commerce is at present obtained. The process by whieh benzene is obtained industri- ally was first worked out by a pupil of Hof- mann's, Charles jManslleld, 'whose death was caused (1850) by a large quantity of benzene taking fire during a distillation. "Most of the benzene produced by the destructive distillation of coal forms a constituent of illuminating gas, while the remaining benzene is found in the por- tion of the coal-tar that distils over below 170° C. When this portion, caHed light oil, is redistill- ed, a liquid consisting mainly of benzene and a similar substance called toluene passes over be- tween 82° and 110° C. This portion is purified by washing consecutively with sulphuric acid, water, and soda; it is then subjected to further fractional distillation. In this manner still somehat impure benzene is obtained. To purify it, the liquid is cooled to crystallization, and the benzene crystals are separated and again dis- tilled. Thus benzene is rendered pure enough for all practical purposes. It still contains, how- ever, a small quantity of the compound called thiophene (CJI.S), whose presence may be best demonstrated by the so-called indophenin reac- tion, causing a blue coloration to appear when a little sulphuric acid and isatin are added to ordinary benzene. As thiophene is more readily soluble in sulphuric acid than benzene, it may be eliminated from the latter by repeatedly agi- tating with the concentrated acid at the ordi- nary temperature. A better method, however, consists in boiling benzene for about half an hour with some aluminium chloride, and then distill- ing. In this manner ])erfectly pure benzene may be prepared for scientific purposes. Pure benzene Is a light, colorless liquid, having a peculiar odor and a_ burning taste. At low temperatures it solidifies, forming colorless crvstals that melt at 6° C, and boil at 80.5° C. 'The vapors burn with a smoky flame, owing mainly to the high percentage of carbon contained in benzene. Ben- zene floats on water, but mixes readily with ether, anhydi-ous alcohol, petroleum, and many other organic liquids. When treated with strong nitric acid, it is converted into nitrobenzene, ac- cording to the following equation:

C„H, + HNO, = C„H,NO, + H,0

Benzene Nitric .4cid Nitro-benzene Water The French chemist Berthelot succeeded in converting acetylene gas into benzene by heating the former at a dull-red heat, the conversion taking place according to the following simple chemical equation :

3C,H, = C„H,

Acetylene Benzene

As acetylene (q.v.) can be made directly from carbon and hydrogen, it may be said tlua't benzene, too, can be made from its ekments. For an account of the chemical constitution of ben- zene and its derivatives, see Carbon Compounds.

BENZER'TA. See Bizerta.

BEN'ZIDINE, H,N.C,H,.C„H,.NH=. A valu- able organic substance derived from benzene. In the pure state, it forms crystals that melt at 122° C. Benzidine and its derivatives are now used in making many beautiful coloring sub- stances, including the well-known Congo red and the benzopurpurins. The dyes have the re- markable property of combining with cotton