Ionic Entablature
The total height of the entablature is divided into ten parts; three of these should be taken as the height of the architrave, three that of the frieze, and the remaining four that of the cornice.
To find the projection of the cornice a line should be drawn at an angle of 45 degrees from the top of the frieze, and the profiles of the mouldings composing the cornice will fall within this line.
The lowest member is a small reversa moulding, with a fillet supporting a dentil course, above which is an ovolo; these occupy half the height of the cornice. The remaining half is composed of the facia, surmounted by a reversa and the crowning cyma moulding, rather more than half of the height being allotted to these two.
The frieze of the Ionic order has no characteristic detail as the Doric, and may be plain or decorated according to conditions, and should be in vertical alignment with the lowest member of the architrave. In some of the later Renaissance examples the profile of the Ionic frieze is a segmental curve of about a third of a circle.
The architrave is usually formed of three facias, which may be either vertical or slightly inclined.
No. 158. Corinthian Entablature.
A fifth of the total height is taken for the upper moulding, which is a reversa with its accompanying fillet.
A point bisecting the underside of the fillet and bottom of architrave will give the line of the lower edge of the top facia. The other two facias should be taken in a decreasing ratio, the lower being the shorter.