Physical geography. By Mary Somerville ...

CHAP. XX. EUROPEAN LAKES. 259
volcanic crater. There is scarcely a valley in the Alpine range and
its offsets that has not a sheet of water, no doubt owing to the cavities formed during the elevation of the ridges, and in some instances
to subsidence of the soil: Lake Triib, 7200 feet above the level of
the sea, is the most elevated. There are more lakes on the north
than on the south side of the Alps-the German valleys are full of
them. In Bohemia, Gallicia, and Moravia there are no less than
30,000 sheets of water, besides great numbers throughout the Austrian empire.
Of the principal lakes on the northern side of the Alps, the Lake
of Geneva, or Lake Leman, is the largest and most beautiful, from
its situation, the pure azure of the waters, and the sublime mountains that surround it. Its surface, of about 240 square miles, is
1230 feet above the sea, and near Meillerie it is 1012 deep. The
Lake of Lucerne is 1407 feet above the sea, and the lakes of Brienz
1900 feet. The Italian Lakes are at a lower level; the Lago Maggiore has only 678 feet of absolute altitude; they are larger than
most of those on the north of the Alps, and, with the advantage of
an Italian climate, sky, and vegetation, they surpass the others in
beauty, though the mountains that surround them are less lofty.
These great lakes are fed by rivers rising in the glaciers of the
higher Alps, and many large rivers issue from them. In this respect they differ from most of the lakes in Lower Italy, some of
which are craters of ancient volcanoes, or perhaps ancient craters of
elevation, where the earth had been swelled up by subterranean
vapour without bursting, and had sunk down again into a hollow
when the internal pressure was removed.'
In Syria, the Lake of Tiberias and the Dead Sea, sacred memorials to the Christian world, are situate in the deepest cavity on the
earth. The surface of the Lake Tiberias is 329 feet below the level
of the Mediterranean, surrounded by verdant plains bearing aromatic shrubs; while the heavy bitter waters of the Dead Sea, 1312
feet below the level of the Mediterranean, is a scene of indescribable
desolation and solitude, encompassed by desert sands, and bleak,
stony, salt hills. Thus there is a difference of level of 983 feet in
little more than 60 miles, which makes the course of the river
Jordan very rapid. The water of the Dead Sea is so acrid from the
large proportion of saline matter it contains, that it irritates the skin:
it is more buoyant, and has a greater proportion of salt,2 than any
that is known except the small lake of Eltonsk east of the Volga.
1 The Lake of Perugia or Thrasymene is an exception.
2 It would appear to be completely saturated with salt, if it be true, as
stated by the American expedition under Lieut. Lynch, that the sounding
lead brought up crystals of salt from its bottom in several parts. The extreme saltness of the Dead Sea appears to be owing to the saliferous strata