SECTION VI. The average rise and fall of the tide is about three feet (varying considerably with the seasons; [Footnote: Appendix III, "Tides of Venice."]) 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 flicker and dance before the strong winds upon the unlifted level of the shallow sea. But the scene is widely different at low tide. A fall of eighteen or twenty inches is enough to show ground over the greater part of the lagoon; and at the complete ebb the city is seen standing in the midst of a dark plain of seaweed, of gloomy green, except only where the larger branches of the Brenta and its associated streams converge towards the port of the Lido. Through this salt and sombre plain the gondola and the fishing-boat advance by tortuous channels, seldom more than four or five feet deep, and often so choked with slime that the heavier keels furrow the bottom till their crossing tracks are seen through the clear sea water like the ruts upon a. wintry road, and the oar leaves blue gashes upon the ground at every stroke, or is entangled among the thick weed that fringes the banks with the weight of its sullen waves, leaning to and fro upon the uncertain sway of the exhausted tide. The scene is often profoundly oppressive, even at this day, when every plot of higher ground bears some fragment of fair building: but, in order to know what it was once, let the traveller follow in his boat at evening the windings of some unfrequented channel far into the midst of the melancholy plain; let him remove, in his imagination, the brightness of the great city that still extends itself in the distance, and the walls and towers from the islands that are near; and so wait, until the bright investiture and, sweet warmth of the sunset are withdrawn from the waters, and the black desert of their shore lies in its nakedness beneath the night, pathless, comfortless, infirm, lost in dark languor and fearful silence, except where the salt runlets plash into the tideless pools, or the seabirds flit from their margins with a