1drive the lower Wedges cloſer together, and
ſo keep them tight to their Duty. The filling
up, or ſtuffing between the Arches ſhould be
wrought with the ſtrongeſt Stone, and with the
cloſeſt Joynts that can poſſibly be made, But
if you have not a ſufficient Plenty of ſtrong
Stone to make your Stuffing of it, you may in
Caſe of Neceſſity make uſe of a weaker Sort;
ſtill provided that the whole Turn of the Arch,
and the Courſe of Work behind both the Sides
of it, be built entirely of ſtrong Stone.
ſo keep them tight to their Duty. The filling
up, or ſtuffing between the Arches ſhould be
wrought with the ſtrongeſt Stone, and with the
cloſeſt Joynts that can poſſibly be made, But
if you have not a ſufficient Plenty of ſtrong
Stone to make your Stuffing of it, you may in
Caſe of Neceſſity make uſe of a weaker Sort;
ſtill provided that the whole Turn of the Arch,
and the Courſe of Work behind both the Sides
of it, be built entirely of ſtrong Stone.
THE next Work it to pave the Bridge; and
here we ſhould obſerve, that we ought to
make the Ground upon a Bridge as firm and
ſolid as the moſt durable Roads; we ſhould
raiſe it with Gravel or coarſe Sand, to the
Heighth of a Cubit, and then pave it with
Stone, filling up the Joints either with River
or Sea-ſand. But the Subſtrature or Layer
under the Pavement of a Bridge ought firſt to
be levelled and raiſed quite to the Top of the
Arches; with regular Maſonry, and then the
Pavement itſelf ſhould be cemented with Mor
tar. In all other Reſpects we ſhould obſerve
the ſame Rules in paving a Bridge, as in pav
ing a Road. The Sides ſhould be made firm
with the ſtrongeſt Work, and the reſt paved
with Stones, neither ſo ſmall as to be eaſily
raiſed and thrown out upon the leaſt Strain;
nor ſo large, that the Beaſts of Burden ſhould
ſlide upon them as upon Ice, and fall before
they meet with any Catch for their Foot. And
certainly we muſt own it to be of very great
Importance what Kind of Stone we uſe in our
Pavements, if we conſider how much they
muſt be worn by the continual grinding of
the Wheels, and the Hoofs of all Manner of
Cattle, when we ſee that even ſuch ſmall Ani
mals as Ants, with conſtant paſſing up and
down, will wear Traces even in Flints.
here we ſhould obſerve, that we ought to
make the Ground upon a Bridge as firm and
ſolid as the moſt durable Roads; we ſhould
raiſe it with Gravel or coarſe Sand, to the
Heighth of a Cubit, and then pave it with
Stone, filling up the Joints either with River
or Sea-ſand. But the Subſtrature or Layer
under the Pavement of a Bridge ought firſt to
be levelled and raiſed quite to the Top of the
Arches; with regular Maſonry, and then the
Pavement itſelf ſhould be cemented with Mor
tar. In all other Reſpects we ſhould obſerve
the ſame Rules in paving a Bridge, as in pav
ing a Road. The Sides ſhould be made firm
with the ſtrongeſt Work, and the reſt paved
with Stones, neither ſo ſmall as to be eaſily
raiſed and thrown out upon the leaſt Strain;
nor ſo large, that the Beaſts of Burden ſhould
ſlide upon them as upon Ice, and fall before
they meet with any Catch for their Foot. And
certainly we muſt own it to be of very great
Importance what Kind of Stone we uſe in our
Pavements, if we conſider how much they
muſt be worn by the continual grinding of
the Wheels, and the Hoofs of all Manner of
Cattle, when we ſee that even ſuch ſmall Ani
mals as Ants, with conſtant paſſing up and
down, will wear Traces even in Flints.
I HAVE obſerved that the Ancients in many
Places, and particularly in the Way to Tivoli,
paved the Middle of the Road with Flints, and
only covered the Sides with ſmall Gravel. This
they did, that the Wheels might make the leſs
Impreſſion, and that the Horſes Hoofs might
not want ſufficient Hold. In other Places, and
eſpecially over Bridges, there was a raiſed Way
on each Side, with Stone Steps, for Foot Paſ
ſengers; and the Middle of the Way was leſt
for Beaſts and Carriages. Laſtly, the Ancients,
for this Sort of Work greatly commend Flints,
and eſpecially thoſe which are fulleſt of Holes;
not becauſe ſuch are the ſtrongeſt, but becauſe
they are the leaſt ſlippery. But we may make
uſe of any Sort of Stone, according to what
we have in greateſt Plenty, provided we only
uſe the ſtrongeſt we can get, and with thoſe
pave at leaſt that Part of the Way which is
moſt beaten by Cattle; and the Part moſt
beaten by them is always moſt level, becauſe
they always avoid all ſloping Ground as much
as they can. Let the Middle and higheſt Part
of the Way be laid with Flints, or whatever
other Stone you uſe, of the Thickneſs of a
Foot and an half, and the Breadth of at leaſt
a Foot, with the upper Face even, and ſo cloſe
compacted together that there are no Grevices
left in order to throw off the Rain. There
are three different Slopes for all Streets; either
towards the Middle, which is proper for a
broad Street, or to the Sides, which is leaſt
Hindrance to a narrow one; or elſe Length
ways. But in this we are to govern ourſelves
according to the Conveniences and Advanta
ges of our Drains and Currents, whether into
the Sea, Lake or River. A very good Riſe
for a Slope is half an Inch in every three Foot.
I have obſerved that the Riſe with which the
Ancients uſed to build their Bridges, was one
Foot in every thirty; and in ſome Parts, as
particularly at the Summit of the Bridge, four
Inches in every Cubit or Foot and an half;
but this was only for ſo little a Way, that a
Beaſt heavy loaden could get over it at one
Strain.
Places, and particularly in the Way to Tivoli,
paved the Middle of the Road with Flints, and
only covered the Sides with ſmall Gravel. This
they did, that the Wheels might make the leſs
Impreſſion, and that the Horſes Hoofs might
not want ſufficient Hold. In other Places, and
eſpecially over Bridges, there was a raiſed Way
on each Side, with Stone Steps, for Foot Paſ
ſengers; and the Middle of the Way was leſt
for Beaſts and Carriages. Laſtly, the Ancients,
for this Sort of Work greatly commend Flints,
and eſpecially thoſe which are fulleſt of Holes;
not becauſe ſuch are the ſtrongeſt, but becauſe
they are the leaſt ſlippery. But we may make
uſe of any Sort of Stone, according to what
we have in greateſt Plenty, provided we only
uſe the ſtrongeſt we can get, and with thoſe
pave at leaſt that Part of the Way which is
moſt beaten by Cattle; and the Part moſt
beaten by them is always moſt level, becauſe
they always avoid all ſloping Ground as much
as they can. Let the Middle and higheſt Part
of the Way be laid with Flints, or whatever
other Stone you uſe, of the Thickneſs of a
Foot and an half, and the Breadth of at leaſt
a Foot, with the upper Face even, and ſo cloſe
compacted together that there are no Grevices
left in order to throw off the Rain. There
are three different Slopes for all Streets; either
towards the Middle, which is proper for a
broad Street, or to the Sides, which is leaſt
Hindrance to a narrow one; or elſe Length
ways. But in this we are to govern ourſelves
according to the Conveniences and Advanta
ges of our Drains and Currents, whether into
the Sea, Lake or River. A very good Riſe
for a Slope is half an Inch in every three Foot.
I have obſerved that the Riſe with which the
Ancients uſed to build their Bridges, was one
Foot in every thirty; and in ſome Parts, as
particularly at the Summit of the Bridge, four
Inches in every Cubit or Foot and an half;
but this was only for ſo little a Way, that a
Beaſt heavy loaden could get over it at one
Strain.
CHAP. VII.
Of Drains or Sewers, their different Sorts and Uſes; and of Rivers and
Canals for Ships.
Canals for Ships.
Drains or Sewers are look'd upon as
a Part of the Street, inaſmuch as they
are to be made under the Street, thro' the
Middle of it; and are of great Service, as well
in the paving and levelling, as in cleaning the
Streets; for which Reaſon they are by no
means to be neglected here. And indeed, may
we not very properly ſay that a Drain is a
a Part of the Street, inaſmuch as they
are to be made under the Street, thro' the
Middle of it; and are of great Service, as well
in the paving and levelling, as in cleaning the
Streets; for which Reaſon they are by no
means to be neglected here. And indeed, may
we not very properly ſay that a Drain is a