Penrose, Francis: An investigation of the principles of Athenian architecture: or the results of a recent survey conducted chiefly with reference to the optical refinements exhibited in the construction of the ancient buildings at Athens (London [u.a.], 1888)

GENERAL DESCRIPTION OF THE ATHENIAN PROPYL.'EA

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by the cave of Pan and up the narrow and winding staircase shown on Plates II. and XXVII., and
this also converged to the broad platform already referred to.

The lower flight of steps, which leads downwards from the broad platform described above to
the Beule' gateway, is clearly defined in extent and direction, with the exception of a few of its
upper steps, by the bed cut in the rock. It has a gradient of 270 26' 27", and occupies a width equal
to the whole extent of the front of the Propylasa, with no interruption from a central plane roadway

like that which breaks the continuity of the upper flight. Although the gradient of these steps is
about the same as that of the upper flight, the steps themselves are lower, being .656 x 1.359 instead
of .79x1.60, a difference which confirms the view taken above that they belong to a later period.

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