Archimedes Texts

224
the Water, must vary according to the Quan
tity of the Stream, and the Situation of the
Pipe by which it makes it discharge. The
greater and more rapid the Stream is from
whence the Water is brought, the more direct
Way it is brought, and the more it has been
confined, the more the Mouth of the Conduit
must be enlarged. If the discharging Pipe be
placed direct to the Stream and Level, it will
maintain an equal Discharge. It has been
found by Experience, that this Pipe is wasted
away by the continual Spray of the Water,
and that no Metals stand it so well as Gold.
Thus much of Conduits and Aqueducts. Wa
ter may also be brought in leaden Pipes, or ra
ther in earthen ones, because the Physicians
tell us, that those of Lead occasion an Exco
riation of the Bowels, and so too will Brass.

THE Learned tell us, that whatever we
either drink or eat, is best preserved in Vessels
of baked Earth, which the least alters their
Taste; alledging that the Earth is the natural
Place of Repose, as well of Water as of every
Thing else which is produced by the Earth.
Wooden Pipes give Water in Time an ill Co
lour, and an unpleasant Taste. Whatever Ma
terial they are made of, the Pipes ought to be
as strong as possible. Vessels of Brass are apt
to give the Epilepsy, Canker, and so breed Dis
orders in the Liver and Spleen. The Sides of
the Pipes must be in Thickness at least one
fourth Part of the Diameter of the Hollow,
and the Joints of the Bricks of which they are
made be mortised into one another, and ce
mented with unslaked Lime mixed with
Oil; they should also be fortified all round
with strong Brick Work, and strengthened
a good Weight of Work over them, especially
where you bring the Water about winding, or
where after a Descent it is to rise upwards
again, or where the Pipe upon a short Turn
is straitened and made narrower. For the
Weight and continual Pressure of the Water,
with the Force and Impetuosity of its Cur
rent, would easily carry away or break the
Bricks. Experienced Workmen, in order to
guard against this Danger, and especially about
the Windings, made use of a living Stone,
and particularly of the red Sort, bored through
for the Purpose. I have seen Pieces of Marble
above twelve Foot long bored through from
one End to the other with a Bore of four
Inches Diameter, which by plain Marks in the
Stone itself appeared to have been made
with an Instrument of Brass turned with a
Wheel and with Sand. In order to prevent
the Effects of this Impetuosity, you may
slacken the Current of the Water, by making
it run winding, not indeed with a sharp Elbow,
but with an easy Sweep, turning sometimes to
the Right, sometimes to the Left, sometimes
rising, sometimes descending with a frequent
Variety. To this you may add somewhat in
the Nature of a Conduit-head or Mill-dam, in
order for the Water to purify there, and also if
any Defect should happen, that you may the
more easily come to see how and where it
must be repaired. But these Heads should not
be placed in the Bottom of the Sweep of a
Valley, nor where the Water is forced upwards,
but where it keeps on its Course more equally
and gently. If you are obliged to carry your
Conduit-pipes through a Lake or Marsh, you
may do it with a very small Expence, in the
following Manner. Provide some good Tim
bers of Scarlet Oak, and in them Lengthways
cut a Gutter in Breadth and Depth in Propor
tion to your Pipes, which you must lay into
this Gutter well cemented with Mortar, and
bound down with good Cramps of Brass. Then
having laid these Timbers upon a Float across
the Lake, sasten the Ends of them together as
follows. You must have Pipes of Lead of the
same Diameter as those upon your Timbers,
and of such a Length as to allow for bend
ing as much as may be necessary. These
leaden Pipes, you must insert into your earthen
ones, and cement their Joints with Lime
slacked with Oil, and fortified with Plates of
Brass. Thus join the Ends of the Timber to
gether, as they hang over your Float, till you
bring them from one Shore quite to the other,
and their Heads rest upon the dry Ground on
each Side. Then withdraw your Float, and
having secured the whole Work with good
Ropes, where the Lake is deepest, let it go
down by little and little to the Bottom, as
equally as possible, all the rest sinking by pro
per Degrees along with it, by which Means
the leaden Pipe will bend according to the
Occasion, and the whole will place itself con
veniently at the Bottom of the Lake. When
the Conduit is prepared in this Manner with
the first Water which you send into it throw
in some Ashes, that if any of the Joints should
happen not to be perfectly close, they may stop
them up, and help to cement them. You
should also let in the Water by gentle Degrees,
lest rushing in too precipitately, it should
struggle with the Wind which is in the Pipe.