and size: they may be of any shape, from
the slit or cross slit to the circle;[56] of any size, from the loophole
of the castle to the pillars of light of the cathedral apse. Yet,
according to their place and purpose, one or two laws of fitness hold
respecting them, which let us examine in the two classes of windows
successively, but without reference to military architecture, which
here, as before, we may dismiss as a subject of separate science, only
noticing that windows, like all other features, are always delightful,
if not beautiful, when their position and shape have indeed been thus
necessarily determined, and that many of their most picturesque forms
have resulted from the requirements of war. We should also find in
military architecture the typical forms of the two classes of outlet and
inlet windows in their utmost development; the greatest sweep of sight
and range of shot on the one hand, and the fullest entry of light and
air on the other, being constantly required at the smallest possible
apertures. Our business, however, is to reason out the laws for
ourselves, not to take the examples as we find them.

Sec. XI. 1. Outlook apertures. For these no general outline is
determinable by the necessities or inconveniences of outlooking, except
only that the bottom or sill of the windows, at whatever height, should
be horizontal, for the convenience of leaning on it, or standing on it
if the window be to the ground. The form of the upper part of the window
is quite immaterial, for all windows allow a greater range of sight
when they are _approached_ than that of the eye itself: it is the
approachability of the window, that is to say, the annihilation of the
thickness of the wall, which is the real point to be attended to. If,
therefore, the aperture be inaccessible, or so small that the thickness
of the wall cannot be entered, the wall is to be bevelled[57] on the
outside, so as to increase the range of sight as far as possible; if the
aperture can be entered, then bevelled from the point to which entrance is
possible. The bevelling will, if possible, be in every direction, that is
to say, upwards at the top, outwards at the sides, and downwards at the
bottom, but essentially _downwards_; the earth and the doings upon it
being the chief object in outlook windows, except of observatories; and
where the object is a distinct and special view downwards, it will be of
advantage to shelter the eye as far as possible from