Return to The Temple of Apollo at Didyma
Inscribed on the unfinished wall of the innermost sanctuary (adyton) of the Temple of Apollo at Didyma is the blueprint for the construction of a column base, that part of the column between the shaft and its plinth. Four horizontal lines were inscribed through a single vertical line, one, three, and fourteen dactyls apart, with another line dividing the last dimension in such a way that a was half the ratio of b. To construct the column base, a quarter circle with a radius b was drawn to form the lower portion of the torus; the upper part was delineated by another quarter circle with a radius a (1). A vertical line from the center of this circle marked the edge of a smaller circle that formed the molding above the torus (2). And a vertical line from the center of that circle delineated the center of a quarter circle c that defined the curve (apophyge) of the column shaft rising from the base.
This geometric construction was changed, however, and the semicircular molding was set back, a vertical line from the center of the smaller circle that formed its edge now serving as the center of a larger circle a which defined the new curve of the column base (3).
At about eye level on the far-left wall of the adyton (top), these horizontal incised lines still can be seen, although scarcely visible without photographing them first and then enhancing the image.
Reference: "The Construction Plans for the Temple of Apollo at Didyma" (1985) by Lothar Haselberger, Scientific American, 253(6), 126-132.