The density of the water averages 1.166. It increases from north to south, and with the depth. The increase is at first rapid, then, after reaching a certain point, becomes more uniform. At 300 metres its density is 1.253. The boiling point is 221° F. To the quantity of solid matter suspended in its water the Dead Sea owes, beside its saltness, its buoyancy and its poisonous properties. The human body floats on the surface without exertion. Owing principally to the large proportion of chloride and bromide of magnesia no animal life can exist in its water. Fish, which abound in the Jordan and in the brackish spring-fed lagoons that exist in one or two places around its shores (such as ‘Ain Feshkhah), die in a very short time if introduced into the main waters of the lake. The only animal life reported from the lake has been some tetanus and other bacilli said to have been found in its mud; but this discovery has not been confirmed. To the chloride of calcium is due the smooth and oily feeling of the water, and to the chloride of magnesia its disagreeable taste. In Roman times curative properties were ascribed to the waters: Mukaddasi (A.D. 985) asserts that people assembled to drink it on a feast day in August. The salt of the Dead Sea is collected and sold in Jerusalem; smuggling of salt (which in Turkey is a government monopoly) is a regular occupation of the Bedouin. The bitumen which floats to shore is also collected. The origin of this bitumen is disputed: it was supposed to be derived from subaqueous strata of bituminous marl and rose to the surface when loosened by earthquakes. It is, however, now more generally believed that it exists in the breccia of some of the valleys on the west side of the lake, which is washed into the sea and submerged, till the small stones by which it is sunk are loosened and fall out, when the bitumen rises to the surface.
History.—The earliest references to the sea or its basin are in the patriarchal narratives of Lot and Abraham, the most striking being the destruction of the neighbouring cities of Sodom and Gomorrah. (See [Sodom].) The biblical name is the Salt Sea, the Sea of the Arabah (the south end of the Jordan valley), or the East Sea. The name in Josephus is Asphaltites, referring to the bituminous deposits above alluded to. The modern name is Bahr Lūt or “Sea of Lot”—a name hardly to be explained as a survival of a vague tradition of the patriarch, but more probably due to the literary influences of the Hebrew Scriptures and the Koran filtering through to the modern inhabitants or their ancestors. The name Dead Sea first appears in late Greek writers, as Pausanias and Galen. At En-Gedi on its western bank David for a while took refuge. South of it is the stronghold of Masada, built by Jonathan Maccabaeus and fortified by Herod in 42 B.C., where the last stand of the Jews was made against the Romans after the fall of Jerusalem, and where the garrison, when the defences were breached, slew themselves rather than fall into Roman hands.
The sea has been but little navigated. Tacitus and Josephus mention boats on the lake, and boats are shown upon it in the Madeba mosaic. The navigation dues formed part of the revenue of the lords of Kerak under the crusaders. In modern times navigation is practically nil. The lake, with the whole Jericho plain, is claimed as the personal property of the sultan.
The medieval travellers brought home many strange legends of the sea and its peculiarities—some absurd, others with a basis of fact. The absence of sea-birds, due to the absence of fish, probably accounts for the story that no birds could fly over it. The absence of vegetation on its shores, due to the scanty rainfall and general want of fresh water—except in the neighbourhood of springs like ‘Ain Feshkhah and ‘Ain Jidi, where a luxuriant subtropical vegetation is found—accounts for the story that no plant could live in the poisonous air which broods over the sea. The mists, due to the great heat and excessive evaporation, and the noxious miasmata, especially of the southern region, were exaggerated into the noisome vapours that the “black and stinking” waters ever exhaled. The judgment on Sodom and Gomorrah (which of course they believed to be under the waters of the lake, in accordance with the absurd theory first found in Josephus and still often repeated) blinded these good pilgrims to the ever-fresh beauty of this most lovely lake, whose blue and sparkling waters lie deep between rocks and precipices of unsurpassable grandeur. The play of brilliant colours and of ever-changing contrasts of light and shade on those rugged mountain-sides and on the surface of the sea itself might have been expected to appeal to the most prosaic. The surface of the sea is generally smooth (seldom, however, absolutely inert as the pilgrims represented it), but is frequently raised by the north winds into waves, which, owing to the weight and density of the water, are often of great force.
The first to navigate the sea in modern times was an Irish traveller, Costigan by name, in August and September 1835. Owing largely to the folly of his Greek servant, who, without his master’s knowledge, threw overboard the drinking-water to lighten the boat, the explorer after circumnavigating the sea reached Jericho in an exhausted condition, and was there attacked by a severe fever. The greatest difficulty was experienced in obtaining assistance for him, but he was ultimately conveyed on camel-back to Jerusalem, where he died; his grave is in the Franciscan cemetery there. His fate was shared by his successor, a British naval officer, Lieutenant Molyneux (1847), whose party was attacked and robbed by Bedouins. W. F. Lynch, an American explorer (1848), equipped by the United States government, was more successful, and he may claim to be the first who examined its shores and sounded its depths. Since his time the duc de Luynes, Lartet, Wilson, Hull, Blanckenhorn, Gautier, Libbey, Masterman and Schmidt, to name but a few, have made contributions to our knowledge of this lake; but still many problems present themselves for solution. Among these may be mentioned (1) the explanation of a remarkable line of white foam that extends along the axis of the lake almost every morning—supposed by Blanckenhorn to mark the line of a fissure, thermal and asphaltic, under the bed of the lake, but otherwise explained as a consequence of the current of the Jordan, which is not completely expended till it reaches the Lisān, or as a result of the mingling of the salt water with the brackish spring water especially along the western shore; (2) a northward current that has been observed along the east coast; (3) various disturbances of level, due possibly to differences of barometric pressure; (4) some apparently electrical phenomena that have been observed in the valley. Before we can be said to know all that we might regarding this most interesting of lakes further extensive scientific observations are necessary; but these are extremely difficult owing to the impossibility of maintaining self-registering instruments in a region practically closed to Europeans for nearly half the year by the stifling heat, and inhabited only by Bedouins, who are the worst kind of ignorant, thievish and mischievous savages.
(R. A. S. M.)
DEADWOOD, a city and the county-seat of Lawrence county, South Dakota, U.S.A., about 180 m. W. of Pierre. Pop. (1890) 2366; (1900) 3498, of whom 707 were foreign-born; (1905) 4364; (1910) 3653. It is served by the Chicago, Burlington & Quincy and the Chicago & North-Western railways. It lies on hilly ground in the canyon of Whitewood Creek at an elevation of about 4530 ft. Deadwood is the commercial centre of the Black Hills. About it are several gold mines (including the well-known Home-stake mine), characterized by the low grade of their ores (which range from $2 to $8 per ton), by their vast quantity, and by the ease of mining and of extracting the metal. The ore contains free gold, which is extracted by the simple process of stamping and amalgamation, and refractory values, extracted by the cyaniding process. Several hundred tons of ore are treated thus in Deadwood and its environs daily, and its stamp mills are exceeded in size only by those of the Treadwell mine in S.E. Alaska, and by those on the Rand in South Africa. The discovery of gold here was made known in June 1875, and in February 1877 the United States government, after having purchased the land from the Sioux Indians, opened the place for legal settlement.
DEAF AND DUMB.[1] The term “deaf” is frequently applied to those who are deficient in hearing power in any degree, however slight, as well as to people who are unable to detect the loudest sounds by means of the auditory organs. It is impossible to draw a hard and fast line between the deaf and the hearing at any particular point. For the purposes of this article, however, that denotation which is generally accepted by educators of the deaf may be given to the term. This makes it refer to those who are so far handicapped as to be incapable of instruction by the ordinary means of the ear in a class of those possessing normal hearing. Paradoxical though it may seem, it is yet true to say that “dumbness” in our sense of the word does not, strictly speaking, exist, though the term “dumb” may, for all practical purposes, fairly be applied to many of the deaf even after they are supposed to have learnt how to speak. Oral teachers now confess that it is not worth while to try to teach more than a large percentage of the deaf to speak at all. We are not concerned with aphasia, stammering or such inability to articulate as may be due to malformation of the vocal organs. In the case of the deaf and dumb, as these words are generally understood, dumbness is merely the result of ignorance in the use of the voice, this ignorance being due to the deafness. The vocal organs are perfect. The deaf man can laugh, shout, and in fact utter any and every sound that the normal person can. But he does not speak English (if that happens to be his nationality) for the same reason that a French child does not, which is that he has never heard it. There is in fact no more a priori reason why an English baby, born in England, should talk English than that it should talk any other language. English may be correctly described as its “mother tongue,” but not its natural language; the only reason why one person speaks English and another Russian is that each imitated that particular language which he heard in infancy. This imitation depends upon the ability to hear. Hence if one has never heard, or has lost hearing in early childhood, he has never been able to imitate that language which his parents and others used, and the condition of so-called dumbness is added to his deafness. From this it follows that if the sense of hearing be not lost till the child has learnt to speak fluently, the ability to speak is unaffected by the calamity of deafness, except that after many years the voice is likely to become high-pitched, or too guttural, or peculiar in some other respect, owing to the absence of the control usually exercised by the ear. It also follows that, to a certain extent, the art of speech can be taught the deaf person even though he were born deaf. Theoretically, he is capable of talking just as well as his hearing brother, for the organs of speech are as perfect in one as in the other, except that they suffer from lack of exercise in the case of the deaf man. Practically, he can never speak perfectly, for even if he were made to attempt articulation as soon as he is discovered to be deaf, the fact that the ear, the natural guide of the voice, is useless, lays upon him a handicap which can never be wiped out. He can never hear the tone of his teacher’s voice nor of his own; he can only see small and, in many instances, scarcely discernible movements of the lips, tongue, nose, cheeks and throat in those who are endeavouring to teach him to speak, and he can never hope to succeed in speech through the instrumentality of such unsatisfactory appeals to his eye as perfectly as the hearing child can with the ideal adaptation of the voice to the ear. Sound appeals to the ear, not the eye, and those who have to rely upon the latter to imitate speech must suffer by comparison.