Plate 36. The Erectheum at Athens: Details and the Volute

Plate 36 shows, Figs. 1 to 4, details of the doorway at the northern portico of the Erectheum. This doorway is shown complete on plate 92. At the time of the visit of Stuart & Revett, it was not accessible as the spaces between the columns of the northern portico were walled in and our first knowledge of it was through Inwood (London, 1827). Fig. 1 is the cyma, Fig. 2 is the leaf-wave or egg moulding under the corona, Fig. 3 the Lesbian wave of the architrave, and Fig. 4 a rosette of the latter.

Fig. 5, drawn from a model of the original, gives a larger and more correct representation of the antæ capitals of the 6 columned portico of the Erectheum, and also the capital of the wall. At the right is shown by dotted lines a method for drawing the ornament. For the drawing of the eggs a method is also given on Plate 58. The section at Fig. 5 is through the antæ capital. At A, B, C and D are shown other sections through the ornament.

Fig. 6, A, B and C shows a method, invented by Mauch, of drawing the volute of the Ionic capital of the Erectheum:

The dimension of the volute is 7 times the diameter of the eye in height and 6 times in width. The center of the eye is 4 of its diameters from the upper edge and 3[…] from the outer edge of the volute. The volute line after circling around three times should be drawn so that it will be tangent to the eye at its highest point. The vertical diameter of the eye is to be divided into 16 parts, of which the central two, four, and eight form, respectively, one side of three squares, and are so drawn that their inner sides coincide with the vertical diameter of the eye. (See diagram below.) The horizontal diameter bisect the squares, and the corners 1 to 12 are the center points for the curves a b, b c, etc., to m n. (The spiral is continued as an imaginary line, shown dotted, from n through p q and r to s, the centers being 13, 14, 15 and 16 at the corners of an inner square of one part of the eye.) The radius of the finish of the spiral at n from the center of the eye o is the same as the radius of the eye or 8 parts; at m, 9 parts, at 1, 11; at k, 13; at i, 15; at h, 18; at g, 22; at f, 26; at e, 30; at d, 36; at c, 44; at b, 52; and at a, 60, which plus 4 brings us to the center of the eye o. Therefrom it will be seen that a e=e o; b f=f o, etc., and that the width of each winding of the volute is half the width of the one lying outside of same or vice versa. Fig. 6, C shows the volute developed. At the end of this wedge the profile is shown and from there the lines concentric with both sides converge at the point o. The channel in the central member is an exception to this; it converges in the first three-quarter winding at which point the central member changes into a bead. The length of the wedge a o is to be taken optionally as a diagram. After the single volute line a b c to n is described at A and developed at C, the intermediate members of a spiral are easily attained and the centers lie proportional between the centers of the main curves of the spiral; so, the centers of the intermediate spirals of the 9th quarter spiral at B between i k and n p, described from points 9 and 13, lie between these points.

A comparison of this volute with a model of a corner column capital of the Erectheum shows only unimportant differences, the eye of the original is a little more than 1-7 the height of the volute, in consequence the periphery or circumference becomes tangent at the eleventh quadrant, instead of the twelfth. The larger eye of the original is shown by dotted line, the center being at 12.

This method serves also for the drawing of the volute on the capital of Minerva Polias but not, so well for the capital of the Ilissus Temple at Athens, because the latter has a very large eye, about 1-5 the height of the volute. The volute line on later, though less exemplary monuments, coincide more nearly with the volute line given by Vitruvius, which is given on Plates 51 and 52 under the names of Palladio, Vignola and Goldmann.