Archimedes Texts

65
heaps of sand, carrying them by the tide; and force of the waves
into the Lake; it not having on its part any sttength of current
that may raise and carry them away, they sink to the bottom, and
so they choke up the Ports. And that this effect happeneth in
this manner, we have most frequent experiences thereof along the
Sea-coasts: And I have observed in Tuscany on the Roman
shores, and in the Kingdom of of Naples, that when a river fal
leth into the Sea, there is alwaies seen in the Sea it self, at the place
of the rivets out-let, the resemblance, as it were, of an half-Moon,
or a great shelf of settled sand under water, much higher then the
rest of the shore, and it is called in Tuscany, il Cavallo; and here
in Venice, lo Scanto: the which cometh to be cut by the current
of the river, one while on the right side, another while on the
left, and sometimes in the midst, according as the Wind fits. And
a like effect I have observed in certain little Rillets of water,
along the Lake of Bolsena; with no other difference, save that of
small and great.

Now whoso well considereth this effect, plainly seeth that it
proceeds from no other, than from the contrariety of the stream
of the River, to the impetus of the Sea waves; seeing that
great abundance of sand which the Sea continually throws upon
the shore, cometh to be driven into the Sea by the stream of the
river; and in that place where those two impediments meet
with equal force, the sand setleth under water, and thereupon is
made that same Shelf or Cavallo; the which if the river carry
water, and that any considerable store, it shall be thereby cut
and broken; one while in one place, and another while in ano
ther; as hath been said, according as the Wind blows: And
through that Chanel it is that Vessels fall down into the Sea, and
again make to the river, as into a Port. But if the Water of
the river shall not be continual or shall be weak, in that case the
force of the Sea-Wind shall drive such a quantity of sand into
the mouth of the Port, and of the river, as shall wholly choak it
up. And hereupon there are seen along the Sea-side, very many
Lakes and Meers, which at certain times of the year abound with
waters, and the Lakes bear down that enclosure, and run into
the Sea.

Now it is necessary to make the like reflections on our Ports
of Venice, Malamocco, Bondolo, and Chiozza; which in a certain
sense are no other than Creeks, mouths, and openings of the shore
that parts the Lake from the main Sea; and therefore I hold that
if the Waters in the Lake were plentiful, they would have
strength to scowr the mouths of the Ports thorowly, & with great
force; but the Water in the Lake failing, the Sea will with
out any opposal, bring such a drift of sand into the Ports; that if