level of the stylobate is gained, will also be taken with the
same foot. The rise of the step ought not to exceed ten
inches, nor be less than nine, in order that the ascent may
not be too difficult: the width should be at the least a foot
and a half, but ought never to exceed two feet. If steps
be adopted on all sides, they should still observe the same
proportions: but when a podium is to be constructed on
three sides, the whole height, including the plinth, dye,
corona and lysis’, must not exceed the level of the stylobate.
The stylobate ought not to be constructed upon the horizontal
level, but should rise gradually from the ends towards the
centre, so as to have there a small addition. The inconvenience,
which might arise from a stylobate thus constructed, may
be obviated by means of unequal scamilli?. If the line of
Lysis, derived perhaps from the Greek alusis, a chain, or band. A kind of
plinth or step above the cornice of the podium, which surrounds or embraces the
stylobate; as we may observe in the temple of Fortuna Virilis.
2 The use and application of the addition which we are directed to give to the
middle of the stylobate, has been a subject of controversy with all the commentators
on Vitruvius: and the position of the scamilli impares has produced many elaborate
dissertations. Baldus, amongst others, has written upon it to a considerable extent;
without producing any satisfactory elucidation. The object of our author in
reducing every thing to the guidance of physical principles, is evident in various
parts of his work; and may be traced throughout the whole of the present chapter;
in which we are repeatedly directed to pursue certain measures calculated to
counteract the supposed imperfections of vision.
The rule for making an addition to the stylobate was undoubtedly prompted by
the same consideration. The image formed by the rays which pass through a convex
lens from a straight line is not, like the object, straight, but somewhat curved; and
is in fact part of a conic section. In like manner the image of a straight line, formed
upon the retina, is curved, whether the line be vertical or horizontal. Owing to this
defect of vision, if it may be so called, it might appear that the line of the stylobate
would form a curved image; and be what Vitruvius terms, alveolated; that is,