tures in the wall veil, the door and window; respecting
which there are three main points to be considered.

1. The form of the aperture, _i.e._, its outline, its size, and the
forms of its sides.

2. The filling of the aperture, _i.e._, valves and glass, and their
holdings.

3. The protection of the aperture, and its appliances, _i.e._, canopies,
porches, and balconies. We shall examine these in succession.

Sec. II. 1. The form of the aperture: and first of doors. We will, for
the present, leave out of the question doors and gates in unroofed walls,
the forms of these being very arbitrary, and confine ourselves to the
consideration of doors of entrance into roofed buildings. Such doors
will, for the most part, be at, or near, the base of the building;
except when raised for purposes of defence, as in the old Scotch border
towers, and our own Martello towers, or, as in Switzerland, to permit
access in deep snow, or when stairs are carried up outside the house for
convenience or magnificence. But in most cases, whether high or low, a
door may be assumed to be considerably lower than the apartments or
buildings into which it gives admission, and therefore to have some
height of wall above it, whose weight must be carried by the heading of
the door. It is clear, therefore, that the best heading must be an
arch, because the strongest, and that a square-headed door must be
wrong, unless under Mont-Cenisian masonry; or else, unless the top of
the door be the roof of the building, as in low cottages. And a
square-headed door is just so much more wrong and ugly than a connexion
of main shafts by lintels, as the weight of wall above the door is
likely to be greater than that above the main shafts. Thus, while I
admit the Greek general forms of temple to be admirable in their kind, I
think the Greek door always offensive and unmanageable.

Sec. III. We have it also determined by necessity, that the apertures
shall be at least above a man's height, with perpendicular sides (for
sloping sides are evidently unnecessary, and even inconvenient,
therefore absurd) and level threshold; and this aperture we at present
suppose simply cut through the wall without any bevelling of the jambs.
Such a door, wide enough for two persons to pass each other easily, and
with such fillings or valves as we may hereafter find expedient, may be
fit enough for any building into which entrance is required neither
often, nor by many persons at a time