n this bank and the
true shore consists of the sedimentary deposits from these and other
rivers, a great plain of calcareous mud, covered, in the neighborhood of
Venice, by the sea at high water, to the depth in most places of a foot
or a foot and a half, and nearly everywhere exposed at low tide, but
divided by an intricate network of narrow and winding channels, from
which the sea never retires.

In some places, according to the run of the currents, the land has risen
into marshy islets, consolidated, some by art, and some by time, into
ground firm enough to be built upon or fruitful enough to be cultivated:
in others, on the contrary, it has not reached the sea-level; so that,
at the average low water, shallow lakelets glitter among its irregularly
exposed fields of seaweed. In the midst of the largest of these,
increased in importance by the confluence of several large river
channels toward one of the openings in the sea-bank, the city of Venice
itself is built, on a crowded cluster of islands; the various plots of
higher ground which appear to the north and south of this central
cluster have at different periods been also thickly inhabited, and now
bear, according to their size, the remains of cities, villages, or
isolated convents and churches, scattered among spaces of open ground,
partly waste and encumbered by ruins, partly under cultivation for the
supply of the metropolis.

The average rise and fall of the tide are about three feet--varying
considerably with the seasons--but this fall, on so flat a shore, is
enough to cause continual movement in the waters, and in the main canals
to produce a reflux which frequently runs like a mill-stream. At high
water no land is visible for many miles to the north or south of Venice,
except in the form of small islands crowned with towers or gleaming with
villages; there is a channel, some three miles wide, between the city
and the mainland, and some mile and a half wide between it and the sandy
breakwater called the Lido, which divides the Lagoon from the Adriatic,
but which is so low as hardly to disturb the impression of the city's
having been built in the midst of the ocean, although the secret of its
true position is partly, yet not painfully, betrayed by the clusters of
piles set to mark the deep-water channels, which undulate far away in
spotty chains like the studded backs of huge sea-snakes, and by the
quick glittering of the crisped and crowded waves that flicke