This accidental circumstance is
probably the reason why the Lagunes have a more determined character at
the mouths of the minor streams that empty themselves here than at the
mouths of most of the other rivers, which equally flow from the Alps or
the Apennines into the same shallow sea.
The natural consequence of a current of a river meeting the waters of
any broad basin, and where there is no base of rock, is the formation,
at or near the spot where the opposing actions are neutralized, of a
bank, which is technically called a bar. The coast of the Union
furnishes constant evidence of the truth of this theory, every river
having its bar, with channels that are often shifted, or cleared, by the
freshets, the gales, or the tides. The constant and powerful operation
of the south-eastern winds on one side, with the periodical increase of
the Alpine streams on the other, have converted this bar at the entrance
of the Venetian Lagunes, into a succession of long, low, sandy islands,
which extend in a direct line nearly across the mouth of the gulf. The
waters of the rivers have necessarily cut a few channels for their
passage, or, what is now a lagune, would long since have become a lake.
Another thousand years may so far change the character of this
extraordinary estuary as to convert the channels of the bay into rivers,
and the muddy banks into marshes and meadows, resembling those that are
now seen for so many leagues inland.
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