The Egyptian architect had recourse to the same motive, first, in the tombs of the Ancient Empire for the decoration of the chamber walls in the mastabas; secondly, for the relief of great brick surfaces. The resemblance to the Mesopotamian work is sometimes very great.[313]
We have explained this form by one of the transpositions so frequent in the history of architecture, namely, a conveyance of motives from carpentry to brickwork and masonry.[314] In the former the openings left in the skeleton are gradually filled in, and these additions, by the very nature of their materials, most frequently take the form of panels. The grooves that define the panels in brick or stone buildings represent the 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 Chaldæa 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]
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.
Fig. 103.—Lateral façade of the palace at Firouz-Abad; from Flandin and Coste.