Must we conclude that stone columns were unknown in Chaldaea and Assyria? As for Chaldaea, we have no positive information in the matter, but we know that she had no building stone of her own. The Chaldaean sculptor might indeed import a few blocks of diorite or basalt, either from Arabia, Egypt, or the valleys of Mount Zagros, for use in statues which would justify such expense; but the architect must have been restricted to the use of material close at hand. In Assyria limestone was always within reach, and yet the Assyrians never succeeded in freeing themselves from traditional methods sufficiently to make the column play a part similar to that assigned to it by the peoples of Egypt and Greece. Their habits, and especially the habit of respect for the practices and traditions of Chaldaea, were too strong for them. Their use of the column, though often tasteful and happy, is never without a certain timidity. One is inclined to think they had an inkling of the possibilities latent in it, but that they lacked the courage necessary to give it full play in the interiors and upon the facades of their large palaces and towers. In the bas-reliefs we find columns used in the kiosques built upon the river banks (Fig. 41), and in the pavilions or chapels studded over the royal gardens (Fig. 42). The excavations, moreover, have yielded pedestals and capitals which, rare as they are, have a double claim to our regard. The situations in which they have been discovered seem to show that columns were sometimes used in front of doorways, to support porches or covered ways extending to the full limits of the esplanade; secondly, their forms themselves are interesting. Close study will convince us that, when copied by neighbouring peoples who made frequent and general use of stone supports, they might well have exercised an influence that was felt as far as the AEgaean, and had something to do with one of the fairest creations of Greek art. We thus catch side glimpses of the column, as it were, in small buildings, in the porches before the principal doors of palaces, and in the open galleries with which some of the latter buildings were crowned (Fig. 39). In all these cases it is nothing but a more or less elegant accessory; we might if we pleased give a sufficiently full description of Mesopotamian architecture without hinting at its existence. [Illustration: FIG. 41.--Temple on the bank of a river, Khorsabad; from Botta.] We cannot say the same of the arch, which played a much more important _role_ than it did in Egypt. There it was banished, as we have seen, to the secondary parts of an edifice. It hardly entered into the composition of the nobler class of buildings; it was used mainly in store-rooms built near the temples, in the gateways through the outer walls of tombs, and in underground cellars and passages.[162] In Mesopotamia, on the other hand, the arch is one of the real constituent elements of the national architecture.