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)

44 The Grecian Orders

PLATE XVI.
The ornaments Intended to decorate the apertures of doors and windows, are desined
(d) either according to the Doric, (the Ionic,' or the Corinthian mode of mouldings and profile.
For the Doric doors or windows A. A. divide the breadth of the aperture into five etjasQ parts -
take one of these sor the height os the architrave, and for the breadth of the jamb; divide
this breadth into twelve equal parts for a modulary scale; and if a 'frize and cornice, and
columns are to be added, let the diraensions,of the members and mouldings be regulated by
that scale according to the rules already given, and the figures described in this plate.
For the Ionic window B. divide its breadth into six equal parts; the breadth of the jamb
is equal to one of these, which divided into eighteen modulary parts, will serve as a scale to
determine all the members, according to the Ionic diilribution. The pediment is' traced in the
manner already prescribed. The architrave and jambs have two facias, and the diagonal os
the little square os the undermost facia in the architrave, prolonged as seen in the figure, by
the dotted lines, determines the knee of the jamb.
For the Corinthian window C. divide the breadth of the aperture into seven equal parts, and take
one for the breadth of the jamb and the 'height of the architrave; the several members of
both, as well as the frize and cornice, are traced from a modulary scale of one of the above
seven parts subdivided into eighteen parts; such particulars being observed as are characteristic
of the Corinthian order. The length of the truss or scroll {U) is continued below the
aperture half of the height of the architrave; but the foliage at the bottom of the lesser
scroll descends slail lower: the breadth of the truss in front is three fifths of the jamb, and
the profile or presecture of the larger volute is equal to one and one half of its front.
Doors, and even windows, are srequently adorned with an order of columns; which become
very rich decorations, as may be observed in the front of the Palazzo Braciani, .near the S. S. Apo-
stoli at Rome, and at the tabernacles within the Pantheon. When this sort of dressing is intended,
set oss from the sill of the window, upwards, the height of the proposed column, see fig.
D. divide this altitude agreeably to the intended order, and finissi the entablature accord-
ingly, observing, however, that it is belt to omit mutules, dentels, and modilions in the
cornices of the orders when used sor these purposes, because they turn out in general too
minute, and cannot take place in such situations with propriety.
To the windows already mentioned, we (hall add the Venetian Windows: these are adapted
to ihir-cases, or to such rooms as require a disferent distribution of the apertures, or more
light than can be obtained from the breadth of one, of two, or of three os the usual apertures.
The symmetry to be regarded in one of these windows, is, that the breadth to each side, be
either one sourth, one or two thirds, or one half of the middle aperture, according as this
may be surnished with three or four panes in breadth.
Sometimes the architrave of a Venetian window is described to range in a right line, as the
sigure E. And if the middle is required to he circular, by tracing the archivolt and entablature,

{a) Ostiorum autcm k eorum antepngrncntorum in jEdlbus ha: Gjnt rationes, vui primum constituantur, quo generc sunt
suture. Genera Cunt enim tbyrom.icoon box, Doricum, lonicum, Atticntges. Lib. IV. c. 6.

(l>) Ancones sive proihyndcs vecemur, cxcii'nt^ de.-ara ac slnislra prawndcant ad imi siincrcilu libr
Lib. IV. c. 6.

prater solium.