Such a development is not to be found in Egypt. The forms of Egyptian architecture did not become less substantial with the passage of the centuries. It is possible that familiarity with light structures of wood and metal had early created a taste for slender supports. The polygonal and faggot-shaped columns of Beni-Hassan are no thicker than those of far later times. A comparison of the columns at Thebes points to the same conclusion. The shortest and most thick-set in its proportions of them all (Fig. 78) is at Medinet-Abou, and is about two centuries later than those of the same order which decorate the second court at Luxor (Fig. 77). Its heaviness is even more apparent when we compare it with the great columns of a different order, at Karnak (Fig. 80), and the Ramesseum (Fig. 81), which precede it by at least a century. The progress of Egyptian art was, then, less continuous and less regular than that of classic art. It had moments of rest, of exhaustion, even of retrogression. It was not governed by internal logical principles so severe as those of the Greeks. The manner in which the capital is allied to the shaft below, and the architrave above shows changes of the same kind. The first duty of the capital is to oppose a firm and individual contour to the monotony of the shaft. The constructor has to determine a point in the length of the latter where it shall cease to be, where its gradual diminution in section, a diminution which could not be prolonged to the architrave without compromising the safety of the building, shall be arrested. The natural office of the capital would seem to be to call attention to this point. The architect, therefore, gives it a diameter greater than that of the shaft at the point where they meet. This salience restores to the column the material which it has lost; it completes it, and determines its proportion, so that it is no longer capable of either increase or diminution. Again, when the salience is but the preparation for a greater development above, it seems to add to the solidity of the edifice by receiving the architrave on a far larger surface than the shaft could offer. The support seems to enlarge itself, the better to embrace the entablature. The two requirements which the capital has to fulfil may, then, be thus summarized: in the first place, it has to mark the point where the upward movement of the lines comes to an end; and, secondly, it has to make, or to seem to make, the column better fitted to play its part as a support. Its functions are dual in principle; it has to satisfy the æsthetic desires of the eye, and the constructive requirements of the material. The latter office may be more apparent than real, but, in architecture, what seems to be necessary is so.