Pennethorne, John; Robinson, John [Ill.]: The geometry and optics of ancient architecture: illustrated by examples from Thebes, Athens, and Rome (London [u.a.], 1878)

THE COLUMNS.

133

Fig.l

In this instance the capital, as shown in Fig. 1 has the following subdivision of parts,
namely, the abacus, the volutes, the elliptical lines connecting the volutes, the echinus, and
the hypotrachelium.

The general proportions of the capital being given, then the design of the volute will
be found to divide into two parts—

Firstly. The volute is proportioned by means of a rectangular spiral line ABCD, A'B'CT)',

AWD"; and

Secondly. The boundaries of each spiral line being given, then the spiral curves are described
within this rectangular spiral line by one simple and uniform method to be explained.

The Return Side of the Ionic Capital.

On the return side of the capital we have in every example an elliptical curved surface,
as shown in Fig. 2, the method of describing which, will be explained in Plates IX. and X.,
showing the return sides of the capitals.

Fig. 2.—The Return Side of the Volute.