'The Expedition for the survey of the rivers Euphrates and Tigris, carried on by order of the British government, in the years 1835, 1836, and 1837; preceded by geographical and historical notices of the regions situated between the rivers Nile and Indus. In four volumes. With fourteen maps and charts, and embellished with ninety-seven plates, besides numerous wood-cuts. Volume the first.' [‎403] (482/905)

CHAP. XVII.]
ASPHALTUM, ETC.
403
Sea, 1 from whence a sandy beach and salt marsh open into
the continuation of the El Ghor, which afterwards, under the
name of the Wadi A seasonal or intermittent watercourse, or the valley in which it flows. Arabah extends to the gulf of Akabah ; it
is on a higher level than the Dead Sea and the river Jordan ;
and, like the valley of the latter, the range bounding its
eastern side is higher than that on the western side.
The quantity of rock-salt found near the south-western Cause^of the ^
and south-eastern shores of the lake sufficiently accounts for
its waters.
the great density of its waters, which is supposed to exceed
that of any other sea, 2 and also for their buoyancy, which is
such as to permit persons to float in them who are unable
to swim in fresh water. 3
The sulphur, nitre, and asphaltum found in the neighbour- Asphaitum.
hood indicate a volcanic country; and the presence of the
last substance is sufficiently evident by the odour which is
perceived not only in the immediate neighbourhood but even
at some distance from the lake. It bubbles up from the
bottom and collects on the surface of the water, generally in
small quantities, which find their way to the shore ; but
occasionally it forms a large mass like an island; and this,
being discovered, is speedily broken up and sold by the Arabs, 4
as it was in ancient times, when it produced a considerable
revenue. 5
The evaporation from a body of water which for seven or Great evapom-
eight months is exposed to a burning sun, concentrating its 10n -
rays on a basin of naked rock, must be very great; and at times
its sombre-looking exhalations have the appearance of water
spouts. 6 The Wadis contain the Seyal, which produces
gum Arabic, 7 the semr, 8 the thorny nubk or sidr, 9 the tama-
1 Travels of Irby and Mangles, p. 452.
8 Biblical Researches, &c., vol. II., p. 224.
3 Strabo XVI., p. 763; and Dr. Robinson experienced the same thing.
Biblical Researches, &c., vol. II., p. 213. J P* ^f 0 '
* Diodorus Siculus, lib. II., ch. XXIX., and Strabo, XVI., p. 764.
« Irby and Mangles' Travels, p. 447. 7 Biblical Researches, &c., p. 210.
8 Mimosa unguis Cati, Forskal's Flor. Egypt, p. 176.
9 Orlote-tree, the Rhamnus nebeca of Forskal. Biblical Researches, &c.,
P> 210 - 3 F 2