opens, with no direct communication between adjoining rooms through
partition-walls. In this way all the sections of an edifice were
clustered together and at the same time isolated; and each of these
sections had its special use and its pre-assigned occupants.[2]

Drains were contrived under the palaces, and certain square rooms were
covered with dome-shaped vaults.

The houses, built of brick, were of two different types; some were
covered with hemispherical or parabolical calottes, others had flat
roofs with a tower in the fashion of a belvedere. They were generally
quite low, except in large cities like Babylon, where they were
sometimes three or four stories high.

The towns were regularly laid out; the streets ran at right-angles to
each other; quays were built along the streams, and bridges established
communication between their banks. The large cities were protected by a
fortified wall. The gates were arched and flanked each by two towers
which were separated by only the width of the entrance. Some of the
gates were ornamented, others were plain, but each one was in itself an
edifice of quite complicated structure.

The city gate played then, as it still does all through the East, an
important rôle in the life of the urban populations. It was an agora for
the Greeks, a forum for the Romans. The people gathered there to chat,
and learn the news, and there the old men acted as arbitrators in case
of quarrels. In the same way it was at the palace-gates, which were
always constructed on the model of the city-gates, that the court
attendants assembled, and that petitioners stood in waiting.