APPENDIX. 205 and many fine capitals exist which have their volutes complete while the eyes are still unfinished. Amongst these is one of the Ephesus capitals, where the eyes are not only nearly 5 inches across but show lines of construction and compass marks which have often been pointed out. The late Prof Middleton drew attention to the fact that similar lines might be traced on one of the Priene capitals. These are now very dim, and only under the electric light have I been able to verify the statement (Fig. 212 A). Chandler reports that at Athens " we found an Ionic capital with marks of the compasses used in forming the volute." We may bring Penrose's theory to bear on the elucidation of the marks on the Ephesus capital. On examination it will be found that many of the centre points on the eye fall into the course of a spiral, as suggested on Fig. 212 B. And if from the . centres thus obtained arcs are successively struck, a spiral results which, I believe, agrees with the actual volute. I sug- gest, then, that * the Greek method of con- structing the volute was to draw four intersect- ing lines on the eye, then to sketch on it a rough spiral according to the number of revolutions required. The centres for successive arcs of circles were found at the intersection of this small and rude spiral with the eight radii. If the dimensions of a perfect spiral of this type are laid down on ordinates they should give a smooth parabolic curve. (Fig. 2 13 A.) As a matter of fact, at the Erechtheum the points do not give a smooth curve. (Fig. 2 1 3 B.)* Probably the best way of designing a volute would be to sketch it as required, then to set out the dimensions on ordinates, then to " smoothe the curve," and from it to correct the volute.
- I owe this observation to Mr P. Rodeck. On the diagram the points
do not fall on the curve. Fig. 213. — Dimensions ofVolutes set out on Ordinates from circumference of eye.
