e, is one
fourth less high than the architrave, but if there are to be reliefs
upon it, it is one fourth higher than the architrave, so that the
sculptures may be more imposing. Its cymatium is one seventh of the
whole height of the frieze, and the projection of the cymatium is the
same as its height.

11. Over the frieze comes the line of dentils, made of the same height
as the middle fascia of the architrave and with a projection equal to
their height. The intersection (or in Greek [Greek: metope]) is
apportioned so that the face of each dentil is half as wide as its
height and the cavity of each intersection two thirds of this face in
width. The cymatium here is one sixth of the whole height of this part.
The corona with its cymatium, but not including the sima, has the height
of the middle fascia of the architrave, and the total projection of the
corona and dentils should be equal to the height from the frieze to the
cymatium at the top of the corona.

[Illustration: A COMPARISON OF THE IONIC ORDER ACCORDING TO VITRUVIUS
WITH ACTUAL EXAMPLES AND WITH VIGNOLA'S ORDER

A: Showing the orders reduced to equal lower diameters. B: Showing the
orders to a uniform scale.]

And as a general rule, all projecting parts have greater beauty when
their projection is equal to their height.

12. The height of the tympanum, which is in the pediment, is to be
obtained thus: let the front of the corona, from the two ends of its
cymatium, be measured off into nine parts, and let one of these parts be
set up in the middle at the peak of the tympanum, taking care that it is
perpendicular to the entablature and the neckings of the columns. The
coronae over the tympanum are to be made of equal size with the coronae
under it, not including the simae. Above the coronae are the simae (in
Greek [Greek: epaietides]), which should be made one eighth higher than
the height of the coronae. The acroteria at the corners have the height
of the centre of the tympanum, and those in the middle are one eighth
part higher than those at the corners.

13. All the members which are to be above the capitals of the columns,
that is, architraves, friezes, coronae, tympana, gables, and acroteria,
should be inclined to the front a twelfth part of their own height, for
the reason that when we stand in front of them, if two lines are drawn
from the eye, one reaching to the bottom of the building and the other
to the top, that which reaches to the top will be