Page:A History of Art in Chaldæa & Assyria Vol 1.djvu/251

 THE ARCH. 229 side of the vault, four separate and different moulds would be required, besides a fifth, for a brick of which we shall presently have to speak. The four narrow sides of these bricks differ sensibly one from another. The two curved faces being at different distances from the centre, are of unequal lengths, while, as the lower oblique edge is some inches below the upper in the curve, these two edges have different directions. In their disinclination to use stone voussoirs, the Assyrian builders here found them- FIG. 92. Drain at Khorsabad, with pointed nrch. Section in perspective. selves compelled to mould bricks of very complicated form, and the way in which they accomplished their task speaks volumes for their skill. If we cast a glance at our Fig. 92 the first thing that strikes us is the absence of a keystone to the vault. The two rows of voussoirs that are in full view thrust against each other only by a single sharp edge ; there is no keystone between them. In the row immediately behind, however, there is a stone (imperfectly seen in our illustration) that seems to play the part of a key.