DEAD SEA 286 DEAF AND DUMB nettle (L. album), the red (L. purpur- eum), and the yellow (L. Galeobdolon) . DEAD SEA, the usual name, dating from the time of Jerome, for a most re- markable lake in the S. E. of Palestine, called in the Old Testament The Salt Sea, Sea of the Plain, or East Sea; by Josephus, Lacus Asphaltites; and by the Arabs now, Bahr-Lut, "Sea of Lot." It is 46 miles long, with a breadth of from 5 to 9 miles. Its surface, which is lower than that of any water known, is 1,292 feet below the level of the Mediterra- nean. The depth of the greater part, the N. section, is about 1,300 feet. The shape is that of an elongated oval, in- terrupted by a promontory which pro- jects into it from the S. E. The Dead Sea is fed by the Jordan from the N. and by many other streams, but has no apparent outlet. Along the E. and W. borders of the Dead Sea there are lines of bold, and in some cases perpendicular, cliffs. These cliffs are chiefly composed of limestone, and are destitute of vegeta- tion except in the ravines traversed by fresh water streamlets. The N. shores of the lako form an extensive and deso- late muddy fiat, marked by the blackened trunks of trees, with salt. The S. shore is low, level, and marshy, desolate, and dreary. On this shore is the remarkable ridge of rock-salt, 7 miles long and 300 feet high, called Khashm Usdom (Ridge of Sodom). Lava-beds, pumice-stone, warm springs, sulphur, and volcanic slag prove the presence here of volcanic agen- cies at some period. The salinity of the waters is adverse to life, though some lower organizations are found in them. The water of the Dead Sea is charac- terized by the presence of a large quan- tity of magnesian and soda salts. Its specific gravity ranges from 1172 to 1227 (pure water being 1000). The pro- portion of saline matter is so great, that while sea-water contains only 3.5 per cent, of salts, the water of the Dead Sea contains upward of 26 per cent. The evaporation is great, as the heat is in- tense, and the sea rather contracts than increases. Rain hardly ever falls; the water is nearly as blue and clear as that of the Mediterranean. Owing to the great specific gravity of the water, it is almost impossible for the bather to sink in it, strive as he may. Several of those who have navigated and explored the sea have fallen victims to a fatal fever. For the story of the "Cities of the Plain," see Gen. xix.; but according to Captain Conder, "it is now generally agreed that the Dead Sea and Jordan were formed by a great fault or crack in the earth's surface long before the creation of man. It is vain, therefore, to suppose that the 'cities of the plain' were beneath the present sea." DEADWOOD, a city of South Dakota, the county-seat of Lawrence co. It is on the Chicago and Northwestern, and the Chicago, Burlington and Quincy rail- roads. It is the financial and commercial center for the mining region of the Black Hills. There are smelting and reduction works, planing mills, foundry, lime works, etc. The city contains a United States assay office, a public li- brary, and a museum. DEAF AND DUMB, or DEAF- MUTES, persons both deaf and dumb, the dumbness resulting from the deaf- ness which has either existed from birth or from a very early period of life. Such persons are unable to speak because they have not the guidance of the sense of hearing to enable them to imitate sounds. Among the causes assigned for congeni- tal deafness are consanguineous mar- riages, hereditary transmission, scrofula, certain local or climatic conditions, ill health of the mother during pregnancy, etc. Acquired or accidental deafness, which occurs at all ages, is frequently due to such diseases as smallpox, measles, typhus, paralysis, hydrocephalus and other cerebral affections, but more par- ticularly to scarlet fever, which is some- what apt to leave the patient deaf, ow- ing to the inflammatory state of the throat extending to the internal ear, and thus causing suppuration and destruction of the extremely delicate parts of the auditory apparatus. In the greater pro- portion of deaf-mutes no defect is visible or can be detected by anatomical exami- nation, and no applications yet discovered appear to be useful. In ancient times Aristotle and others, and also in the Christian ages, Augus- tinu^ and his contemporaries considered that a.'^f-mutes were incapable of edu- cation. Tn ancient days and also in the Middle Ages there were a few cases known in which spiritual culture was at- tained by the deaf and dumb. In ancient Rome two dumb painters attracted at- tention. The most famous of the more ancient instructors of deaf-mutes was the Spanish monk Pedro de Ponce at Sahagun, in Leon, who taught four deaf and dumb people to speak. In Germany about the same time the court preacher of Brandenburg, Joachim Pascha, suc- ceeded in teaching his deaf and dumb daughter to speak. In 1648 John Bulwer published the earliest work in England on the instruc- tion of the deaf and dumb. This was followed by Dalgarno's "Ars Signorum" (Art of Signs) in 1661 and Dr. W. D. 19 — Vol. in — Cyc
