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

104 THE CURVES OF THE HORIZONTAL LINES,

given point of sight, and that the Greeks first calculated the concave appearance of these lines,
to suit the given point of sight, and then selected from the calculated quantities the amount
of curvature that could be safely given to the Upper Step; and this regulated all the other
dimensions.

It is remarkable how carefully the Greeks calculated the perspective effect of their
designs, and corrected every apparent defect, both in the general proportions and in the hori-
zontal lines. The principle of calculating the perspective effect is no doubt correct, and in
such a work as the Parthenon, all the refinements that we meet with were essential to its
beauty and perfection as a work of Art.