er, over the whole
of a building, but only in those parts where more than the ordinary
cohesive power was required. Thus, at Warka, in the ruin called
_Bouvariia_, the buttresses that stand out from the main building are of
large burnt bricks set in thick beds of bitumen, the whole forming such a
solid body that a pickaxe has great difficulty in making any impression
upon it.[183]

Travellers have also found traces of the same use of bitumen in the ruins
of Babylon. It seems to have been in less frequent employment in Assyria.
It has there been found only under the two layers of bricks that constitute
the ordinary pavement of roofs, courts, and chambers. The architect no
doubt introduced this coat of asphalte for two purposes--partly to give
solidity to the pavement, partly to keep down the wet and to force the
water in the soil to flow off through its appointed channels. A layer of
the same kind was also spread under the drains.[184]

In spite of all their precautions time and experience compelled the
inhabitants of Mesopotamia to recognize the danger of crude brick as a
building material; they endeavoured, therefore, to supplement its strength
with huge buttresses. Wherever the ruins have still preserved some of their
shape, we can trace, almost without exception, the presence of these
supports, and, as a rule, they are better and more carefully built than the
structures whose walls they sustain. Their existence has been affirmed by
every traveller who has explored the ruins of Chaldaea,[185] and in Assyria
they are also to be found, especially in front of the fine retaining wall
that helps to support the platform on which the palace of Sargon was
built.[186] The architect counted upon the weight of his building, and upon
these ponderous buttresses, to give it a firm foundation and to maintain
the equilibrium of its materials. As a rule there were no foundations, as
we understand the word. At _Abou-Sharein_, in Chaldaea, the monument
described by Taylor and the brick pavement that surrounds it are both
placed upon the sand.[187] Botta noticed something of the same kind in
connection with the palace walls at Khorsabad: "They rest," he says, "upon
the very bricks of the mound without the intervention of any plinth or
other kind of solid foundation, so that here and there they have sunk below
the original level of the platform upon which they are placed."[188]

This was not due to negligence, for in other respects these