ther.[316]

The crenellations we have been describing are those upon the retaining
walls of Sargon's palace at Khorsabad. Those of the _Observatory_ are
slightly different in that they are three stories high instead of two (Fig.
105). The lowest is three bricks wide, the second three, the topmost two.
They are each three bricks high. Why were these battlements given a height
beyond those of the royal palace? That question may be easily answered. The
crenellations of the observatory were destined for a much more lofty
situation than those of the palace. The base of the former monument rose
about 144 feet above the summit of the artificial hill upon which it was
placed; the total elevation was about 190 feet, a height at which ordinary
battlements, especially when for the most part they had nothing but the
face of the higher stories to be relieved against, would be practically
invisible.

[Illustration: FIG. 105.--Battlements from the Khorsabad _Observatory_.]

Whether composed of two or three stages this battlement was always
inscribed within an isosceles triangle; in fact, when a third story was
added, the height and the width at the base increased in the same
proportions. M. Place lays great stress upon this triangle. He makes it cut
the upper angles of each of the superimposed rectangles, as we have done in
our Figs. 104 and 105, and he points out how such a process gives an
outline similar to that of a palisade cut into points at its summit, a
precaution that is often taken to render the escalade of such an obstacle
more difficult, and M. Place is inclined to think that the idea of these
crenellations was suggested by those of a wooden palisade, a succession of
rectangles being substituted for a triangle in order to meet the special
conditions of the new material. To us, however, it hardly appears necessary
to go back to the details of wooden construction to account for these
forms. We find no sign of M. Place's spiked palisades in the bas-reliefs.
The inclosures of the Mesopotamian fields must have consisted of palm
trunks and strong reeds; planks were hardly to be cut from the trees of the
country. Moreover, the mason and bricklayer saw the forms of these
battlements repeated by their hand every instant. Whenever they began a
fresh course the first brick they placed upon the joint between two units
of the course below was the first step towards a battlement. The decoration
obtained by the use of these battlements