Riou, Stephen: The Grecian orders of architecture: delineated and explained from the antiquities of Athens ; also the parallels of the orders of Palladio, Scamozzi and Vignola (London, 1768)

os Architecture,

LATE VI1-.

31

We have observed before, that every Doric structiirc mud be regulated by the triglyphs and
metopes. The proper distribution for a Doric colonade would be only that of two triglyphs, as
designed for the middle of the portal in the last plate; but the necesiky of a wider intercolum-
niation, may, on some occasions, require three triglyphs; in this case the columns may be dis-
posed by couplets, for a sufiicient strength to support the entablature at fig. A.
Near Trevi, between Fuligno and Spoleto, is a little temple, where the portals are supported
at the angles by columns and pilasters in couplets. But this is a corruption of the antique pu-
rity, which conlidered equi-distant columns, with narrow intercolumniations, as producing
the moll deJireable effects, both on account of strength and beauty;
The boasteci colonade of the Louvre by Perrault would have merited much higher commendation,
is the intercolumniations between the center and the ends, had been equidistant, instead of cou-
plets ; thereby the jambs of the niches might have been somewhat obseured, but the very elegant
disposition of the columns, would have sufficiently made amends: it is more essential to avoid
errors in the greater lines of a design, than to be over scrupulous about the minutiae of little parts.
The Grecians called a colonade or portico, Stoa, which gave the name of Stoics to the dis-
ciples os Zeno, who were accustomed to assemble together in the porticos. When a portico
surrounds internally any open oblong or square space, it is called a peristyle, to distinguisti it
srom the periptere, where the columns are disposed without-side.
The Doric Arcade B. is designed without columns; sor this purpose, the height of the arch
is to its breadth as seven to four j (and it loses its proportional character* if made higher.) Di-
vide the given height a. b. into eleven equal parts, take two for the height of the entablature*
which by the proper modulation is divided into the requisite members. Let the extent of four
triglyphs and three metopes fix the breadth of the aperture, then the breadth of the pier wilt
consist os two metopes and one triglyph. The rest may be collected by inspection os the
figure.
If with the above breadth for the aperture os the arch, you make its height only once and a
half its breadth, it would then admit of semicolumns against the piers, raised upon plinths, as
fig. E. but the cxpences of columns against the piers of arcades seem very useless sor common
purposes. For theatres and amphitheatres, the addition of the semicolumns to the piers, gave an
additional strength, by increasing the depths of the piers, and served to break the too great
plainness or nakedness which othcrwise would have appeared upon such vast extents. Pilasters
projecting srom the piers of arcades, from one eighth to one fourth of their diameters, have
sometimes taken place instead os semicolumns. The archivolt C. and the import D. should
have their members and mouldings characteristkally described from the architraves in every order.
Key-stones, whether plain or scrolled, with ornaments of malts or foliage, interrupting the
members of the archivolt, give it an apparent weakness, and destroy the beautiful effect and
simplicity of the semicircular sweep: perhaps it may not be judged so by others, who will bring
against this opinion the authority of key-stones from some of the Roman antiquities, and srom
the practice os several of the best moderns; but if an ornament is ill-placed, no authority mould
protect it.