[Illustration: PLATE XL.] The whole of the platform is not of a uniform height. On the contrary, it seems to have been composed, as originally built, of several quite distinct terraces. Three of these still remain, exhibiting towards the west a very marked difference of elevation. The lowest of the three is on the south side, and it may therefore be termed the Southern Terrace. It extends from east to west a distance of about 800 feet, with a width of about 170 or 180, and has an elevation above the plain of from twenty to twenty-three feet. Opposite to this, on the northern side of the platform, is a second terrace, more than three times the breadth of the southern one, which may be called, by way of distinction, the Northern Terrace. This has an elevation above the plain of thirty-five feet. Intermediate between these two is the great Central or Upper Terrace, standing forty-five feet above the plain, having a length of 770 feet along the west face of the platform, and a width of about 400. Upon this Upper Terrace were situated almost all the great and important buildings. The erection of a royal residence on a platform composed of several terraces involved the necessity of artificial ascents, which the Persian architects managed by means of broad and solid staircases. These staircases constitute one of the most remarkable features of the place, and seem to deserve careful and exact description. [PLATE XLI., Fig. 2.] [Illustration: PLATE XLI.] The first, and grandest in respect of scale, is on the west front of the platform towards its northern end, and leads up from the plain to the summit of the northern terrace, furnishing the only means by which the platform can even now be ascended. It consists of two distinct sets of steps, each composed of two flights, with a broad landing-place between them, the steps themselves running at right angles to the platform wall, and the two lower flights diverging, while the two upper ones converge to a common landing-place on the top. The slope of the stairs is so gentle that, though each step has a convenient width, the height of a step is in no case more than from three to four inches. It is thus easy to ride horses both up and down the staircase, and travellers are constantly in the habit of ascending and descending it in this way. The width of the staircase is twenty-two feet--space sufficient to allow of ten horsemen ascending each flight of steps abreast. Altogether this ascent, which is on a plan unknown elsewhere, is pronounced to be the noblest example of a flight of stairs to be found in any part of the world. It does not project beyond the line of the platform whereto it leads, but is, as it were, taken out of it. [PLATE XLII.] [[Illustration: PLATE XLII.]