Archimedes Texts

230
the Bank, fill up the Holes immediately, not
with trifling Materials, but with large, solid,
square Stone. It may also be of Service to
lay Bundles of Brushwood underneath the Fall
of the Water, to break its Force before it
comes to the Bottom. We see that the Tyber at
Rome is for the most Part confined with solid
Masonry. Semiramis, not contented with a
strong Bank of Brick, covered it with a Coat
of Plaister made of Bitumen, no less than four
Cubits in Thickness, with Walls for many Fur
longs together equally high with those of the
City. But these are Royal Works. For us,
we may be contented with a Bank of Earth,
like that of Nitocris in Assyria, which was of
Mud, or like those Banks in France which con
fine some very great Rivers, in such a Manner
that they seem to hang in the Air, the Water
in some Places being above the Level of the
Tops of the Cottages: and we may be satisfied
if we can have our Bridges of Stone. Some
commend the Grass Turfs cut out of a Meadow
for making up of Banks: and I think they
will do very well, because the interweaving of
their Roots will fortify the Work, provided
they be rammed very close together: for the
whole Bank, and especially that Part of it
which is washed by the Water, ought to be
so solid as not to be penetrated or disunited.
Some interlace Rods of Ozier in the Bank;
and this makes a very firm Bank, but then it
will last but for a Time, for as such Rods easily
rot, little Rills of Water will penetrate into the
Places of the Twigs which are decayed, and
working their Way onwards, will be apt to
enlarge their Passage till the whole River may
break through in great Streams. There will
not indeed be so much Danger of this if we
take the Oziers when they are green. Others
plant Willows, Elder, Poplars and such other
Trees as love the Water along the Shores in
close Rows. This has some Advantages; but
then it is attended with the same Inconveni
ence which we just now mentioned; for when
the Roots decay, the Water will work its Way
into their Cavities. Others (which I am very
well pleased with) plant the Shore with all
Manner of Shrubs that flourish in the Water,
and strike out more Root than Branches, such
as Lavender, Bulrush, Reeds, and especially
Withes; the last of which pushes out a great
deal of Root, and pierces down into the Earth
with very long Fibres, which are continually
making new Shoots, while at the same Time
its Head is but small, is very pliant, and does
not resist the Stream; and which adds to the
Advantage, this Plant, out of its particular Love
to Water, advances on continually even into
the Current. But where the Bank runs on
parallel with the strong Current of the River,
the Shore ought to be entirely naked and clear,
that nothing may disturb or enrage the Stream,
but that it may run on peaceably. Where the
Bank winding about stands against the Set of
the Current, that it may make the stouter Re
sistance, let it be fortified with good Plank.
But if the whole Force of the River is to be
withstood and opposed; then, in the Summer,
when the Water is lowest, and the Shore is
left dry, make Hurdles bound about strong
Stakes of a good Length, and fastened to them
very tight with stout Braces; lay these Hur
dles with the Heads of the Stakes against the
Current of the Stream, and drive Piles through
them, by Holes made in them before-hand for
that Purpose, as deep as the Nature of the Bot
tom will permit. When this is knit together,
join other Beams to them crossways, and fill up
this Frame with large Stones cemented toge
ther with Mortar; or where the Expence of
Mortar cannot be afforded, you may knit them
together by throwing Bavins of Juniper in a
mongst them. This great Weight will pre
vent the Water from stirring the Frame; and
if any Eddies should get within it, they will
do rather Good than Harm, for by endeavour
ing to work downwards they will make the
whole Weight of Stone sink still lower, and
so strengthen the Foundation still more. But
if the River always keeps at such a Height,
that there is no Opportunity to make such a
Frame, then we must make use of those Me
thods which we formerly taught for erecting
the Piers of a Bridge.

Of the Sea Wall; of strengthening the Port; and of Locks for confining the
Water of a River.

The Sea-shore also is to be fortified with
artificial Banks, but not in the same
Manner as the River, whose Streams does Mif
chief in a different Manner from the Waves of
the Sea. We are told, that the Sea in its own
Nature is quiet and peaceable, but it is agi