1911 Encyclopædia Britannica/Dead Sea
DEAD SEA, a lake in Palestine occupying the deepest part of the valley running along the line of a great “fault” that has been traced from the Gulf of Akaba (at the head of the Red Sea) to Hermon. This fracture was caused after the end of the Eocene period by the earth-movement which resulted in the raising of the whole region out of the sea. Level for level, the more ancient rocks are on the eastward side of the lake: the cretaceous limestones that surmount the older volcanic substrata come down on the western side to the water’s edge, while on the eastern side they are raised between 3000 and 4000 feet above it. In the Pleistocene period the whole of this depression was filled with water forming a lake about 200 m. long north to south, whose waters were about the same level as that of the Mediterranean Sea. With the diminishing rainfall and increased temperature that followed that period the effects of evaporation gradually surpassed the precipitation, and the waters of the lake slowly diminished to about the extent which they still display.
The length of the sea is 47 m., and its maximum breadth is about 912 m.; its area is about 340 sq. m. It lies nearly north and south. Its surface being 1289–1300 ft. below the level of the Mediterranean Sea, it has of course no outlet. It is bounded on the north by the broad valley of the Jordan; on the east by the rapidly rising terraces which culminate in the Moabite plateau, 3100 ft. above the level of the lake; on the south by the desert of the Arabah, which rises to the watershed between the Dead and the Red Sea—6512 m. from the former, 4612 from the latter; height 660 ft.—and on the west by the Judean mountains which attain a height of 3300 ft. On the east side a peninsula, El-Lisān (“the tongue”), of white calcareous marl with beds of salt and gypsum, divides the sea into two unequal parts: this peninsula is about 50 ft. high, and is connected by a narrow strip of marshland with the shore. Its northern and southern extremities have been named Cape Costigan and Cape Molyneux, in memory of two explorers who were among the first in modern times to navigate the sea and succumbed to the consequent fever and exhaustion. North of the peninsula the lake has a maximum depth of 1278 ft.; south of it the water is nowhere more than 12 ft., and in some places only 3 ft. The surface level of the lake varies with the season, and recent observations taken on behalf of the Palestine Exploration Fund seem to show that there are probably cyclical variations also (ultimately dependent on the rainfall), the nature and periodicity of which there are as yet no sufficient data to determine. In 1858 there was a small island near the north end rising 10 or 12 ft. above the surface and connected with the shore by a causeway; this has been submerged since 1892; and owing to the gradual rise of level within these years the fords south of the Lisān, and the pathway which formerly rounded the Ras Feshkhah, are now no longer passable.
The slopes on each side of the sea are furrowed with watercourses, some of them perennial, others winter torrents only. The chief affluents of the sea are as follows:—on the north, Jordan and ʽAin es-Suweimeh; on the east Wadis Ghuweir, Zerka Maʽin (Callirrhoë), Mōjib (Arnon), Ed-Deraʽa, and el-Hesi; on the west, Wadis Muhawāt and Seyāl, ʽAin Jidi (En-Gedi), Wadi el Merabbah, ʽAin Ghuweir, Wadi el-Nar, ʽAin Feshkhah. The quantity of water poured daily into the sea is not less than 6,000,000 tons, all of which has to be carried off by evaporation. The consequence of the ancient evaporation, by which the great Pleistocene lake was reduced to its present modest dimensions, and of the ceaseless modern daily evaporation, is the impregnation of the waters of the lake with salts and other mineral substances to a remarkable degree. Ocean water contains on an average 4-6% of salts: Dead Sea water contains 25%. The following analysis, by Dr Bernays, gives the contents of the water more accurately:—
| Specific gravity 1.1528 at 15.5° C. | ||
| Calcium carbonate | 70.00 | grains |
| Calcium sulphate | 163.39 | |
| Magnesium nitrate | 175.01 | |
| Potassium chloride | 1089.06 | |
| Sodium chloride | 5106.00 | |
| Calcium chloride | 594.46 | |
| Magnesium chloride | 7388.21 | |
| Magnesium bromide | 345.80 | |
| Iron and aluminium oxides | 10.50 | |
| Organic matter, water of crystallization, loss | 317.57 | |
| Total residue per gallon | 15260.00 |
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 ʽAin 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 ʽAin Feshkhah and ʽAin 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.)