t by their height, the same element may be traced. We have endeavoured
to restore some of these by collating the descriptions of the ancient
writers with the remains that still exist in many parts of Mesopotamia
(Plates II., III., and IV.). Their general form may be described as the box
to which we have compared the palace repeated several times in vertical
succession, each box being rather smaller than the one below it. By these
means their builders proposed to give them an elevation approaching the
marvellous. The system was in some respects similar to that of the pyramid,
but the re-entering angles at each story gave them a very different
appearance, at least to one regarding them from a short distance. Only now
and then do we find any inclination like that of the sides of a pyramid,
and in those cases it applies to bases alone (Plate IV.). As a rule the
walls or external surfaces are perpendicular to their foundations.

We may, perhaps, explain the complete absence from Chaldaea of a system of
construction that was so universal in Egypt by the differences of climate
and of the materials used. Doubtless it rains less in Mesopotamia than even
in Italy or Greece. But rain is not, as in Upper Egypt, an almost unknown
phenomenon. The changes of the seasons are ushered in by storms of rain
that amount to little less than deluges.[147] Upon sloping walls of
dressed stone these torrents could beat without causing any great damage,
but where brick was used the inconveniences of such a slope would soon be
felt. Water does not fall so fast upon a slope as upon a perpendicular
wall, and a surface made up of comparatively thin bricks has many more
joints than one in which stones of any considerable size are employed. As a
rule the external faces of all important buildings were revetted with very
hard and well burnt bricks. But the rain, driven by the wind, might easily
penetrate through the joints and spread at will through the core of mere
sun-dried bricks within. The verticality of Assyrian and Chaldaean walls was
necessary, therefore, for their preservation. Without it the thin covering
of burnt brick would have been unable to do its proper work of protecting
the softer material within, and the sudden storms by which the plains were
now and again half drowned, would have been far more hurtful than they
were.

The Chaldaean palace, like the Egyptian temple, sought mainly for lateral
development. Its extent far surpassed its ele