intervals left by the
carpenter between his planks and beams. They could also be obtained very
easily upon the smooth face of beams brought into close contact, either by
means of the gouge or some other instrument capable of cutting into the
wood. We may safely assert that in Chaldaea and Assyria, as in Egypt, it was
with carpentry that the motive in question originated.

On the other hand, if there be a form that results directly from the system
of construction on which it is used, that form is the crenellation with
which, apparently, every building in Mesopotamia was crowned.[315]

[Illustration: FIG. 102.--View of an angle of the observatory at Khorsabad;
compiled from Place.]

The Assyrian brickwork in which so many vast undertakings were carried out
consists of units all of one dimension, and bonded by the simple
alternation of their joints. Supposing a lower course to consist of two
entire bricks, the one above it would be one whole brick flanked on either
side by a half brick. An Assyrian wall or building consists of the infinite
repetition of this single figure. Each whole brick lies upon the joint
between two others, and every perpendicular wall, including parapet or
battlement, is raised upon this system.

[Illustration: FIG. 103.--Lateral facade of the palace at Firouz-Abad; from
Flandin and Coste.]

[Illustration: FIG. 104.--Battlements from an Assyrian palace.]

Far from being modified by the crenellations, this bond regulates their
form, dimensions, and distribution. The crenellations of the palace walls
consist of two rectangular masses, of unequal size, placed one upon the
other. The lower is two bricks'-length, or about thirty-two inches, wide,
and the thickness of three bricks, or about fourteen inches, high. The
upper mass equals the lower in height, while its width is the length of a
single brick, or sixteen inches. The total height of the battlement,
between twenty-eight and twenty-nine inches, is thus divided into two
masses, one of which is twice the size of the other (see Fig. 104). The
battlements are all the same, and between each pair is a void which is
nothing but the space a battlement upside down would occupy. Fill this
space with the necessary bricks, and a section of wall would be restored
identical in bond with that below the battlements, with the one exception
that the highest block of the battlement, being only one brick wide, is
formed by laying three whole bricks one upon the o