em. Some make them seventy-five and others two or three
hundred feet high. There have been many discussions in respect to the
comparative credibility of these several statements, and some
ingenious attempts have been made to reconcile them. It is not,
however, at all surprising that there should be such a diversity in
the dimensions given, for the walling of an ancient city was seldom of
the same height in all places. The structure necessarily varied
according to the nature of the ground, being high wherever the ground
without was such as to give the enemy an advantage in an attack, and
lower in other situations, where the conformation of the surface was
such as to afford, of itself, a partial protection. It is not,
perhaps, impossible that, at some particular points--as, for example,
across glens and ravines, or along steep declivities--the walls of
Babylon may have been raised even to the very extraordinary height
which Herodotus ascribes to them.

The walls were made of bricks, and the bricks were formed of clay and
earth, which was dug from a trench made outside of the lines. This
trench served the purpose of a ditch, to strengthen the fortification
when the wall was completed. The water from the river, and from
streams flowing toward the river, was admitted to these ditches on
every side, and kept them always full.

The sides of these ditches were lined with bricks too, which were
made, like those of the walls, from the earth obtained from the
excavations. They used for all this masonry a cement made from a
species of bitumen, which was found in great quantities floating down
one of the rivers which flowed into the Euphrates, in the neighborhood
of Babylon.

The River Euphrates itself flowed through the city. There was a
breast-work or low wall along the banks of it on either side, with
openings at the terminations of the streets leading to the water, and
flights of steps to go down. These openings were secured by gates of
brass, which, when closed, would prevent an enemy from gaining access
to the city from the river. The great streets, which terminated thus
at the river on one side, extended to the walls of the city on the
other, and they were crossed by other streets at right angles to them.
In the outer walls of the city, at the extremities of all these
streets, were massive gates of brass, with hinges and frames of the
same metal. There were a hundred of these gates in all. They were
guarded by watch-tower