1unload the Barge, which by that Means riſing
higher in the Water, will pull up what is tyed
to it. It will be a Help to the Operation, if
you keep the Veſſel ſtirring about by moving
the Rudder backwards and forwards while you
are unloading it; to ſhew the Uſe of which,
I ſhall juſt mention, that in the Country of
Præneſte I have ſeen a moiſt Sort of Clay into
which if you run a Stick or a Sword but the
Depth of a ſingle Cubit, it was not by the
Force of a Man's Arm to be got out again by
pulling; but if as you pulled you wriggled
your Arm backwards and forwards as Men do
that are turning a Skrew, it would eaſily come
forth. At Genoa there was a Rock lying un
der the Surface of the Water ſo as to ſtop up
the Entrance into the Port. A Man was found
in our Age, endued with ſurprizing Qualifica
tions both of Art and Nature, who broke it
away, and laid the Paſſage very wide. It is
ſaid, that this Man uſed to ſtay under Water
many Hours together, without ever coming
up to take Breath. You may take up the Mud
from the Bottom by means of an Oyſter-net
covered with Tarpawlins; for as you draw it
along it will fill itſelf. You may alſo fetch it
up from the Bottom, where the Sea is ſhallow,
with the following Contrivance. You muſt
have two Smacks, like thoſe of Fiſhermen; in
the Stern of one of theſe you muſt have an
Axis upon which a very long Pole muſt ſwing
like the Beam of a Balance; to that End of
the Pole which lies out from the Stern muſt
be faſten'd a Shovel three Foot broad and ſix
long. By lowering down this Shovel to the
Bottom you ſcoop up the Mud, and ſo throw
it into the other Smack which lies by for that
Purpoſe. From theſe Principles many other
Engines yet more uſeful may be contrived;
but to ſpeak of them here would be too tedi
ous. And thus much may ſuffice for cleaning
any Channel. The Locks in a River are made
either by Sluices or Flood-gates. For either of
theſe the Sides muſt be made full as ſtrong as
the Piers of a Bridge. We may draw up the
heavieſt Sluice without Danger to our Men, by
applying to the Spindle or Windleſs which is
to draw up the Sluice Wheels notch'd with
Teeth like the Wheels in a Clock, which muſt
take hold of the Teeth of the other Spindle
which is to be put in Motion by them. But
the moſt convenient of all is the Flood-gate,
which in the Middle has a Spindle that turns
upon a perpendicular Axis; to this Spindle is
faſtened a broad ſquare Valve, like the ſquare
Sail of a Barge which may be eaſily turned
about to which Side of the Veſſel the Maſter
pleaſes; but the two Sides of this Valve ſhall
not be exactly equal to one another in Breadth,
but let one be above three Inches narrower
than the other; by which means it may be
opened by a Child, and will ſhut again of
itſelf; becauſe the Weight of the broader Side
will exceed that of the Narrower. To
each Lock you ought to make two Stops,
cutting the River in two Places, and leaving
a Space between them equal to the Length of
a Veſſel, to the Intent, that if the Veſſel is to
aſcend, when it comes to the Stop the lower
Sluice may be ſhut the upper one opened; or
if it be to deſcend, the upper one may be ſhut
and the lower opened; for by this means the
Veſſel will run down with the lower Part of
the Stream, while the reſt of the Water is
ſtopp'd by the upper Sluice. There is one
Thing which I muſt not omit concerning
publick Ways, that I may have no Occaſion
for Repetition; namely, that the Streets of a
Town ought never to be heaped up with any
Sort of Rubbiſh, as it is grown a bad Cuſtom
to do under the Notion of mending them,
which ſhould rather be done by removing and
carrying away all the Superfluities; leſt the
Houſes come in Time to be buried, and the
Level of the Town to be ſunk under Rub
biſh.
higher in the Water, will pull up what is tyed
to it. It will be a Help to the Operation, if
you keep the Veſſel ſtirring about by moving
the Rudder backwards and forwards while you
are unloading it; to ſhew the Uſe of which,
I ſhall juſt mention, that in the Country of
Præneſte I have ſeen a moiſt Sort of Clay into
which if you run a Stick or a Sword but the
Depth of a ſingle Cubit, it was not by the
Force of a Man's Arm to be got out again by
pulling; but if as you pulled you wriggled
your Arm backwards and forwards as Men do
that are turning a Skrew, it would eaſily come
forth. At Genoa there was a Rock lying un
der the Surface of the Water ſo as to ſtop up
the Entrance into the Port. A Man was found
in our Age, endued with ſurprizing Qualifica
tions both of Art and Nature, who broke it
away, and laid the Paſſage very wide. It is
ſaid, that this Man uſed to ſtay under Water
many Hours together, without ever coming
up to take Breath. You may take up the Mud
from the Bottom by means of an Oyſter-net
covered with Tarpawlins; for as you draw it
along it will fill itſelf. You may alſo fetch it
up from the Bottom, where the Sea is ſhallow,
with the following Contrivance. You muſt
have two Smacks, like thoſe of Fiſhermen; in
the Stern of one of theſe you muſt have an
Axis upon which a very long Pole muſt ſwing
like the Beam of a Balance; to that End of
the Pole which lies out from the Stern muſt
be faſten'd a Shovel three Foot broad and ſix
long. By lowering down this Shovel to the
Bottom you ſcoop up the Mud, and ſo throw
it into the other Smack which lies by for that
Purpoſe. From theſe Principles many other
Engines yet more uſeful may be contrived;
but to ſpeak of them here would be too tedi
ous. And thus much may ſuffice for cleaning
any Channel. The Locks in a River are made
either by Sluices or Flood-gates. For either of
theſe the Sides muſt be made full as ſtrong as
the Piers of a Bridge. We may draw up the
heavieſt Sluice without Danger to our Men, by
applying to the Spindle or Windleſs which is
to draw up the Sluice Wheels notch'd with
Teeth like the Wheels in a Clock, which muſt
take hold of the Teeth of the other Spindle
which is to be put in Motion by them. But
the moſt convenient of all is the Flood-gate,
which in the Middle has a Spindle that turns
upon a perpendicular Axis; to this Spindle is
faſtened a broad ſquare Valve, like the ſquare
Sail of a Barge which may be eaſily turned
about to which Side of the Veſſel the Maſter
pleaſes; but the two Sides of this Valve ſhall
not be exactly equal to one another in Breadth,
but let one be above three Inches narrower
than the other; by which means it may be
opened by a Child, and will ſhut again of
itſelf; becauſe the Weight of the broader Side
will exceed that of the Narrower. To
each Lock you ought to make two Stops,
cutting the River in two Places, and leaving
a Space between them equal to the Length of
a Veſſel, to the Intent, that if the Veſſel is to
aſcend, when it comes to the Stop the lower
Sluice may be ſhut the upper one opened; or
if it be to deſcend, the upper one may be ſhut
and the lower opened; for by this means the
Veſſel will run down with the lower Part of
the Stream, while the reſt of the Water is
ſtopp'd by the upper Sluice. There is one
Thing which I muſt not omit concerning
publick Ways, that I may have no Occaſion
for Repetition; namely, that the Streets of a
Town ought never to be heaped up with any
Sort of Rubbiſh, as it is grown a bad Cuſtom
to do under the Notion of mending them,
which ſhould rather be done by removing and
carrying away all the Superfluities; leſt the
Houſes come in Time to be buried, and the
Level of the Town to be ſunk under Rub
biſh.
CHAP. XIII.
I shall now proceed to the Remedies for ſome
other Inconveniencies of ſmaller Moment;
in which I ſhall be as brief as poſſible. In
ſome Places, upon bringing Water to them,
the Country has been made warmer; in others,
colder. Near Lariſſa in Theſſaly there was a
Field covered with a ſtanding Water, which
made the Air heavy and hot. Upon carrying
off this Water, and laying the Field dry, the
Country became cooler. The contrary hap
other Inconveniencies of ſmaller Moment;
in which I ſhall be as brief as poſſible. In
ſome Places, upon bringing Water to them,
the Country has been made warmer; in others,
colder. Near Lariſſa in Theſſaly there was a
Field covered with a ſtanding Water, which
made the Air heavy and hot. Upon carrying
off this Water, and laying the Field dry, the
Country became cooler. The contrary hap