deposited in the gulf, at the spot where they have first become subjected to the power of the sea.  Under the influence of counteracting currents, eddies, and waves, the sands have been thrown into submarine piles, until some of the banks have arisen above the surface, forming islands, whose elevation has been gradually augmented by the decay of vegetation.  A glance at the map will show that, while the Gulf of Venice is not literally, it is practically, considered with reference to the effect produced by the south-east wind called the Sirocco, at the head of the Adriatic.  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.

The low margin of sand that, in truth, gives all its maritime security to the port of Venice and the Lagunes, is called the Lido di Palestrino.  It has been artificially connected and secured, in many places, and the wall of the Lido (literally the beach), though incomplete, like most of the great and vaunted works of the other hemisphere, and more particularly of Italy, ranks with the mole of Ancona, and the sea-wall of Cherbourg.  The hundred little islands which now contain the ruins of what, during the middle ages, was the mart of the Mediterranean, are grouped together within cannon-shot of the natural barrier.  Art has united with nature to turn the whole to good account; and, apart from the influence of moral causes, the rivalry of a neighboring town, which has been fostered by political care, and the gradual filling up of the waters, by the constant deposit of the streams, it would be difficult to imagine a more commodious, or a safer haven when entered, than that which Venice affords, even to this hour.