ried out. No cement was to be had which could
resist the action of water for an indefinite period and maintain the
coherence of brickwork subjected to its unsleeping attacks. In order to
obtain piers capable of withstanding the current during the great floods,
it was better too to use blocks of considerable weight, which could be held
together by metal tenons or clasps.

It was but at rare intervals that buildings had to be erected in which the
habits of ages had to be thus abandoned. Why is it that such works have
perished and left no sign? The question may be easily answered. When the
ruins of Babylon began to be used as an open quarry, the stone buildings
must have been the first to disappear. This material, precious by its
rarity and in greater request than any other, was used again and again
until no trace of its original destination or of the buildings in which it
was found remained.

In Assyria long chains of hills traversed the plain and stretched here and
there as far as the borders of the two rivers, besides which the last
buttresses of the mountains of Kurdistan came very near the left bank of
the Tigris. These hills all contained limestone. Two sorts were found: one
fine, hard, close grained, and a little shelly, the other softer and more
friable.

For the decoration of his monumental doorways and the lining of his richest
apartments, the architect chose and committed to the sculptor those fine
slabs of gypseous alabaster of which so many examples are to be seen in the
Louvre and British Museum. In the plains gypsum serves as a base or
foundation for the wide banks of clay that spread over the country, and are
much less thick than in the south of Chaldaea. Alabaster is there to be met
with in great quantities, often but little below the surface of the
soil.[142] It is a sulphate of chalk, gray in colour, soft and yet
susceptible of polish. But it has many defects; it breaks easily and
deteriorates rapidly on exposure to the air. The Assyrians, however, did
not fear to use it in great masses, as witness the bulls in the Louvre and
British Museum. Before removal these carved man-headed animals weighed some
thirty-five tons, and some of those remaining at Khorsabad and Kouyundjik
are still larger.

In Assyria as in Chaldaea the dark and hard volcanic rocks have only been
found in a few isolated fragments. They were used by the statuary and
ornamentist rather than by the architect, and we cannot say for certa