structure of the watershed in the valley of the Arabah to the south, and from the direction of the lateral ravines which fall into the great Jordan valley, that the river Jordan could never have run into the Red Sea. The depression of the Dead Sea is 1308 feet, while the elevation of the watershed is 787 feet ; and the action which upheaved the watershed occurred at the same geological period which gave to the whole of Palestine its present form. The formation of the Jordan valley M. Lartet accounts for in this way. At some remote period a fracture took place in the upper strata in this region, extending north and south. In consequence of the unequal strength of the strata the western side of the fracture sank, occasioning the abrupt dip observable in the strata on the western side of the valley, and the great depression of the valley itself ; while the eastern side of the fracture remained in situ, showing at various places along the eastern shore of the Dead Sea a vertical section through the limestone and sandstone. The basin of the Dead Sea has thus been since its foundation a reservoir for the rain fall : while its saltness originally proceeded from the salt- spring and hills, and gradually increased by evaporation. Deposits of great depth have accumulated in the whole valley since* its formation, composed of beds of gypsum, marl, flint, and alluvium, similar to those now in process of formation at the bottom of the Dead Sea. They show that at one period the whole Jordan valley was under water ; while the sides of the valley indicate successive stages in the fall of the water from the time when its sur face was on the level of the ocean down to the present age. The hill-sides and strips of plain on both the eastern and western banks of the Dead Sea are marked by a series of terraces or shore-lines. The highest has an elevation cor responding to the level of the Mediterranean. About 230 feet above the present level of the lake there is another shore-line, marked by a strip of alluvial marl adhering to the rocks and cliffs, particularly at the north-west angle. The deposit is mixed with shells of existing species, layers of gypsum and gravel. This line would correspond with the general level of the great valley northward, through which the river Jordan has cut a deep channel. There are, besides, in the ravines which descend to the lake, compara tively recent deposits, reaching up their sides in places to a height of 400 feet, and then sloping down in a series of terraces to the present level of the lake, showing the gradual depression of the water. Tristram also remarked on the western shore "no less than eight low gravel terraces, the ledges of comparatively recent beaches, dis tinctly marked. The highest of them was 44 feet above the present sea-level." Many traces of volcanic action, both remote and recent, fcave been observed in the basin of the Dead Sea, such as trap dykes, and hot sulphur and brackish springs. Tristram describes a valley at the northern end of the salt range of Sodom, in which there are " large masses of bitumen mingled with gravel. These overlie a thick stratum of sulphur, which again overlies a thicker stratum of sand so strongly impregnated with sulphur that it yields power ful fumes on being sprinkled over a hot coal. The bitumen, unlike that which we pick up on the shore, is strongly impregnated with sulphur. _ Above all, it is calcined, and bears the marks of having been subjected to extreme heat. So far as I can understand this deposit, if there be any physical evidence left of the catastrophe which destroyed Sodom and Gomorrah, or. of similar occurrences, we have it here. The whole appearance points to a shower of hot sulphur, and an irruption of bitumen upon it, which would naturally be calcined and impregnated with its fumes ; and this at a geological period quite subsequent to all the diluvial and illuvial action of which we have such abundant evidence. The catastrophe must have been since the formation of the vallev, and while the water was at its present level, therefore, probably during the historic period." (Land of Israel, pp. 355, S q.) Tristram applies the above-observed facts to the solution of the great historical question about the destruction of the cities of the plain in the following manner : " Setting aside all preconceived notions, and taking the simple record of Genesis xix. as we find it, let us see whether the existing condition of the country throws any light on the Biblical narrative. Certainly we do observe by the lake sulphur and bitumen in abund ance. Sulphur springs stud the shores, sulphur is strewn, whether in layers or in fragments, over the desolate plains ; and bitumen is ejected in great floating masses from the bottom of the sea, oozes through the fissures of the rocks, is deposited with gravel on the beach, or appears with sulphur to have been precipitated during some convulsion. We know that at the time of earthquakes bitumen seems to be detached from the bottom of the lake. Every thing leads to the conclusion that the agency of fire was at work. The kindling of such a mass of combustible material, either by lightning from heaven, or by other electrical agency, combined with an earthquake ejecting other bitumen or sulphur from tho lake, would soon spread devastation over the plain, so that the smoke of the country would go up as the smoke of a furnace. " (Land of Israel, p. 359). Here we have to do only with physical facts and appearances. A mass of burning sulphurous matter might be ejected from some open crater, as is often the case with Vesuvius ; and this, falling upon the cities and the bituminous plain around them, would produce just such a form of conflagration as Abraham is stated to have seen. The valley may then have sunk a few feet, and become submerged. This, it is true, is mere theory ; it is a theory, however, suggested, and to a large extent confirmed, by the physical aspect of the country, and the careful observations of travellers around the lake. The subject is not one for vague speculation, and much less for dogmatic assertion. The problems which the Dead Sea present must be- solved, if they are ever to be solved, by scientific research. It is not strange that the Dead Sea has never been navigated to any extent. It seems probable from the statement of Josephus (Ant. ix. 1, 2) that the Moabites crossed it to invade Judah ; and he tells us the Romans used boats , against the fugitive Jews (. J. iv. 7, 6). Costigan was the first in modern times to navigate it, going from the mouth of the Jordan to the peninsula of Lisan in the boat by which he had came from Tiberias. He after wards died of fatigue and exhaustion. In 1837 Moore and Beck conveyed a little boat from Joppa, and visited some points. Ten years later Lieutenant Molyneux took a boat to the peninsula, and his life was also sacrificed. The expedition of Lynch was far more successful, and he was the first thoroughly to examine the shores, and to determine the depths by soundings. Several of his party took the fever which is so fatal, and one died. Winter is the proper season for such researches. Rain seldom falls; and the air during the depth of winter is fresh, and cold almost unknown. The following are the leading works which treat of the Dead Sea : Robinson, Physical Geography of Palestine ; De Saulcy, Voyage antour de la Her Morte ; Lynch, Official Report to United States Government; Ritter, Comparative Geography of Palestine, vol. iii. appendix i. (J. L. P.)
DEADLY NIGHTSHADE. See Belladonna.
DEAF AND DUMB. It is a not uncommon supposition
that deaf mutes are dumb on account of some vocal or
organic defect, whereas the dumbness arises, with very
rare exceptions, from the deprivation of hearing caused by
some natural or accidental disease. Where partial or total
dumbness exists with the sense of hearing perfect, it will
be generally found to proceed either from great nervous
debility or from some mental derangement, and not, as is
often supposed, from some defect in the vocal organs,
which in the congenitally deaf, with hardly an exception,
are in their normal condition. Many children who are
numerated as congenitally deaf have the sense of hearing
to a greater or less degree, but not to such an extent as to
be of service to them in the acquisition of language. It is
remarkable that the. defect of hearing is not generally dis-
