1for a Baſement to them you muſt make a
Plinth half the Height of the Baſement at the
Bottom. But nothing can be a greater Orna
ment either to Squares or the Meeting of ſeve
ral Streets, than Arches at the Entrance of the
Streets; an Arch being indeed nothing elſe but
a Gate ſtanding continually open. I am of
Opinion, that the Invention of Arches were
owing to thoſe that firſt enlarged the Bounds
of the Empire: For it was the ancient Cuſtom
with ſuch, as we are informed by Tacitus, to
enlarge the Pomoerium, or vacant Space left
next the City Walls, as we find particularly
that Claudius did. Now though they extend
ed the Limits of the City, yet they thought it
proper to preſerve the old Gates, for ſeveral
Reaſons, and particularly becauſe they might
ſome Time or other happen to be a Safeguard
againſt the Irruption of an Enemy. Afterwards
as theſe Gates ſtood in the moſt conſpicuous
Places, they adorned them with the Spoils
which they had won from their Enemies, and
the Enſigns of their Victories. To theſe Be
ginnings it was that Arches owed their Tro
phies, Inſcriptions, Statues and Relieves. A
very proper Situation for an Arch is where a
Street joins into a Square, and eſpecially in the
Royal Street, by which Name I underſtand the
moſt eminent in the City. An Arch, like a
Bridge, ſhould have no leſs than three open
Paſſages: That in the Middle for the Soldiers
to return through in Triumph to pay their
Devotions to their paternal Gods, and the two
Side ones for the Matrons and Citizens to go
out to meet and welcome them Home. When
you build one of theſe Triumphal Arches, let
the Line of the Platform which runs length
ways with the Street be the Half of the Line
that goes croſs the Street from Right to Left,
and the Length of this Croſs-line ſhould never
be leſs than fifty Cubits. This Kind of Struc
tures is very like that of a Bridge, only it never
conſiſts of more than four Piers and three
Arches. Of the ſhorteſt Line of the Platform
which runs lengthways with the Street, leaves
one eighth Part towards the Square, and as
much behind on the other Side, for the Plat
forms of Columns to be erected againſt the
Piers. The other longer Line which croſſes the
Street muſt alſo be divided into eight Parts,
two whereof muſt be given to the Aperture in
the Middle, and one to each Pier and to each
Side opening. The perpendicular Upright of
the Piers that ſupport the middle Arch, to the
Spring of that Arch, muſt be two of the afore
ſaid Parts and a Third; and the Piers of the
two Side Arches muſt bear the ſame Proporti
on to their reſpective Aperture. The Soffit of
the Arches muſt be perſect Vaults. The
Crowns of the Piers beneath the Spring of the
Arch, may be made in Imitation of the Doric
Capital, only inſtead of the Ovolo and Abacus
they may have a projecting Cornice either Co
rinthian or Ionic, and beneath the Cornice by
Way of Gorgerine, a plain Freze, and below
that an Aſtragal and a Fillet like thoſe at the
Top of the Shaft of a Column. All theſe Or
naments together ſhould take up the ninth Part
of the Height of the Pier. This ninth Part
muſt be again ſubdivided into nine ſmaller Parts,
five whereof muſt be given to the Cornice,
three to the Freze, and one to the Aſtragal
and Fillet. The Architrave or Face of the
Arch that turns from Pier to Pier muſt never
be broader than the tenth Part of its Aperture,
nor narrower than the twelfth. The Columns
that are placed in Front againſt the Piers muſt
be regular and inſulate; they muſt be ſo raiſed
that the Top of their Shafts may be equal to
the Top of the Arch, and their Length muſt
be equal to the Breadth of the middle Aper
ture. Theſe Columns muſt have their Baſes,
Plinths and Pedeſtals as alſo their Capitals,
either Corinthian or Compoſite together with
Architrave, Freze and Cornice, either Ionic or
Corinthian, according to the Proportions al
ready preſcribed for thoſe ſeveral Members.
Above theſe Columns muſt be a plain Wall,
half as high as the whole Subſtructure from
the loweſt Baſement to the Top of the Cornice,
and the Height of this additional Wall muſt
be divided into eleven Parts, one of which muſt
be given to a plain Cornice at the Top, with
out either Freze or Architrave, and one and an
Half to a Baſement with a reverſed Cymatium
which muſt take up one third of the Height of
that Baſement. The Statues muſt be placed
directly over the Intablature of the Columns,
upon little Pedeſtals whoſe Height muſt be
equal to the Thickneſs of the Top of the Shaſt
of the Columns. The Height of the Statues
with their Pedeſtals muſt be eight of the eleven
Parts to which we divided the upper Wall. At
the Top of the whole Structure, eſpecially to
wards the Square, muſt be placed larger Sta
tues, triumphal Cars, Animals and other Tro
phies. The Baſe for theſe to ſtand upon, muſt
be a Plinth three Times as high as the Cor
nice, which is immediately below it. Theſe
larger Statues which we thus place uppermoſt,
Plinth half the Height of the Baſement at the
Bottom. But nothing can be a greater Orna
ment either to Squares or the Meeting of ſeve
ral Streets, than Arches at the Entrance of the
Streets; an Arch being indeed nothing elſe but
a Gate ſtanding continually open. I am of
Opinion, that the Invention of Arches were
owing to thoſe that firſt enlarged the Bounds
of the Empire: For it was the ancient Cuſtom
with ſuch, as we are informed by Tacitus, to
enlarge the Pomoerium, or vacant Space left
next the City Walls, as we find particularly
that Claudius did. Now though they extend
ed the Limits of the City, yet they thought it
proper to preſerve the old Gates, for ſeveral
Reaſons, and particularly becauſe they might
ſome Time or other happen to be a Safeguard
againſt the Irruption of an Enemy. Afterwards
as theſe Gates ſtood in the moſt conſpicuous
Places, they adorned them with the Spoils
which they had won from their Enemies, and
the Enſigns of their Victories. To theſe Be
ginnings it was that Arches owed their Tro
phies, Inſcriptions, Statues and Relieves. A
very proper Situation for an Arch is where a
Street joins into a Square, and eſpecially in the
Royal Street, by which Name I underſtand the
moſt eminent in the City. An Arch, like a
Bridge, ſhould have no leſs than three open
Paſſages: That in the Middle for the Soldiers
to return through in Triumph to pay their
Devotions to their paternal Gods, and the two
Side ones for the Matrons and Citizens to go
out to meet and welcome them Home. When
you build one of theſe Triumphal Arches, let
the Line of the Platform which runs length
ways with the Street be the Half of the Line
that goes croſs the Street from Right to Left,
and the Length of this Croſs-line ſhould never
be leſs than fifty Cubits. This Kind of Struc
tures is very like that of a Bridge, only it never
conſiſts of more than four Piers and three
Arches. Of the ſhorteſt Line of the Platform
which runs lengthways with the Street, leaves
one eighth Part towards the Square, and as
much behind on the other Side, for the Plat
forms of Columns to be erected againſt the
Piers. The other longer Line which croſſes the
Street muſt alſo be divided into eight Parts,
two whereof muſt be given to the Aperture in
the Middle, and one to each Pier and to each
Side opening. The perpendicular Upright of
the Piers that ſupport the middle Arch, to the
Spring of that Arch, muſt be two of the afore
ſaid Parts and a Third; and the Piers of the
two Side Arches muſt bear the ſame Proporti
on to their reſpective Aperture. The Soffit of
the Arches muſt be perſect Vaults. The
Crowns of the Piers beneath the Spring of the
Arch, may be made in Imitation of the Doric
Capital, only inſtead of the Ovolo and Abacus
they may have a projecting Cornice either Co
rinthian or Ionic, and beneath the Cornice by
Way of Gorgerine, a plain Freze, and below
that an Aſtragal and a Fillet like thoſe at the
Top of the Shaft of a Column. All theſe Or
naments together ſhould take up the ninth Part
of the Height of the Pier. This ninth Part
muſt be again ſubdivided into nine ſmaller Parts,
five whereof muſt be given to the Cornice,
three to the Freze, and one to the Aſtragal
and Fillet. The Architrave or Face of the
Arch that turns from Pier to Pier muſt never
be broader than the tenth Part of its Aperture,
nor narrower than the twelfth. The Columns
that are placed in Front againſt the Piers muſt
be regular and inſulate; they muſt be ſo raiſed
that the Top of their Shafts may be equal to
the Top of the Arch, and their Length muſt
be equal to the Breadth of the middle Aper
ture. Theſe Columns muſt have their Baſes,
Plinths and Pedeſtals as alſo their Capitals,
either Corinthian or Compoſite together with
Architrave, Freze and Cornice, either Ionic or
Corinthian, according to the Proportions al
ready preſcribed for thoſe ſeveral Members.
Above theſe Columns muſt be a plain Wall,
half as high as the whole Subſtructure from
the loweſt Baſement to the Top of the Cornice,
and the Height of this additional Wall muſt
be divided into eleven Parts, one of which muſt
be given to a plain Cornice at the Top, with
out either Freze or Architrave, and one and an
Half to a Baſement with a reverſed Cymatium
which muſt take up one third of the Height of
that Baſement. The Statues muſt be placed
directly over the Intablature of the Columns,
upon little Pedeſtals whoſe Height muſt be
equal to the Thickneſs of the Top of the Shaſt
of the Columns. The Height of the Statues
with their Pedeſtals muſt be eight of the eleven
Parts to which we divided the upper Wall. At
the Top of the whole Structure, eſpecially to
wards the Square, muſt be placed larger Sta
tues, triumphal Cars, Animals and other Tro
phies. The Baſe for theſe to ſtand upon, muſt
be a Plinth three Times as high as the Cor
nice, which is immediately below it. Theſe
larger Statues which we thus place uppermoſt,