The Cyma Reversa is employed in the cornice of the Doric order as a supporting moulding to the dentil course and below the culminating Cavetto. It also occurs in the Capital of the column, where it forms the upper member of the abacus. An apparent contradiction of the theory of employment, which however is justified by the circumstance that the column forms the support for the entablature.
It also occurs as a supporting moulding under the capping of the pedestal, and is used in similar positions in the other orders.
Binding Mouldings
The Binding mouldings, the Torus and the Scotia, appear chiefly on columns and pilasters, particularly the Scotia, which is essentially a base moulding.
The Torus
The Torus is a convex curve composed of a full half circle, with upper fillet one-fifth to one-sixth the total height. The projection is decided by the curvature, which is based on a semi-circle with centre slightly in advance of the vertical line of fillet.
The Torus varies in size according to position. For instance, in the base of the Ionic column two are employed, the lower being the larger. It is also invariably used on a smaller scale as a necking moulding beneath the Capitals; in the small form it is commonly known as a bead or astragal.
This employment of the Torus is distinctly appropriate and suggestive in the sense of imparting strength by binding. When used in other positions its purpose should be equally evident.
The Scotia
The Scotia in section is a deeply recessed concave curve with upper fillet, and is generally used between the upper and lower Torii of the base.