y, while around the opening would run a
portico, similar to that of a Roman atrium, whose sloping roof would
protect the reliefs with which the walls were ornamented.[193]

[Illustration: FIG. 50.--Present state of one of the city gates, Khorsabad.
Perspective compiled from Place's plans and elevations.]

As to this, however, doubt had already been expressed by an attentive and
judicial observer like Loftus; who thought that the arch had played a very
important part in the architecture of Mesopotamia.[194] As he very justly
remarked, the conditions were rather different from those that obtained in
the maritime and mountainous provinces of Persia; there was no breeze from
the gulf or from the summits of snowy mountains, to which every facility
for blowing through their houses and cooling their heated chambers had to
be given; the problem to be solved was how best to oppose an impenetrable
shield against a daily and long continued heat that would otherwise have
been unbearable. Now it is clear that a vault with its great powers of
resistance would have been far better fitted to support a roof whose
thickness should be in some reasonable proportion to the massive walls,
than a ceiling of bad timber. In our day the mosques, the baths, and many
of the private houses of Mossoul and Bagdad have dome-shaped roofs. Without
going as far as Mesopotamia, the traveller in Syria may see how
intelligently, even in the least important towns, the native builder has
employed a small dome built upon a square, to obtain a strong and solid
dwelling entirely suited to the climate, a dwelling that should be warm in
winter and cool in summer.

We must also point out that the state in which the interiors of rooms are
found by explorers, is more consistent with the hypothesis of a domed roof
than with any other. They are covered to a depth of from fifteen to twenty
feet with heaps of _debris_, reaching up to the top of the walls, so far as
the latter remain standing.[195] This rubbish consists of brick-earth mixed
with broken bricks, and pieces of stucco. Granting wooden roofs, how is
such an accumulation to be accounted for? Roofs supported by beams laid
across from one wall to the other, could never have safely upheld any great
weight. They must have been thin and comparatively useless as a defence
against the sun of Mesopotamia. On the other hand if we assume that vaults
of pise were the chosen coverings, all the rest follows easily. They cou