The capitals of the pillars were of three kinds. Those of the side colonnades were comparatively simple: they consisted, in each case, of a single member, formed, in the eastern colonnade, of two half-griffins, with their heads looking in opposite directions [PLATE XLVII, Fig. 2]; and, in the western colonnade, of two half-bulls, arranged in the same manner [PLATE XLVII., Fig. 3]. The capitals of the pillars in the northern colonnade, which faced the great sculptured staircase, and constituted the true front of the building, were of a very complex character. They may be best viewed as composed of three distinct members--first, a sort of lotos-bud, accompanied by pendent leaves; then, above that, a member, composed of volutes like those of the Ionic order, but placed in a perpendicular instead of a horizontal direction; and at the top, a member composed of two half-bulls, exactly similar to that which forms the complete capital of the western group of pillars. The pillars of the groat central cluster had capitals exactly like those of the northern colonnade.
The bases of the colonnade pillars are of singular beauty. Bell-shaped, and ornamented with a double or triple row of pendent lotus-leaves, some rounded, some narrowed to a point; they are as graceful as they are rare in their forms, and attract the admiration of all beholders. Above them rise the columns, tapering gently as they ascend, but without any swell or entasis. They consist of several masses of stone, carefully joined together, and secured at the joints by an iron cramp in the direction of the column’s axis. All are beautifully fluted along their entire length, the number of the incisions or flutings being from forty-eight to fifty-two in each pillar. They are arcs of circles smaller than semicircles, thus resembling those of the Doric, rather than those of the Ionic or Corinthian order. The cutting of all is very exact and regular.
There can be little doubt but that both the porches, and the great central pillar-cluster, were roofed in. The double-bull and double-griffin capital are exactly suited to receive the ends of beams, which would stretch from pillar to pillar, and support a roof and an entablature. [PLATE L., Fig.1.] We may see in the entrances to the royal tombs the true use of pillars in a Persian building, and the character of the entablature which, they were intended to sustain, Assuming, then, that both the great central pillar phalanx and the three detached colonnades supported a roof, the question arises, were the colonnades in any way united with the main building, or did they stand completely detached from it? It has been supposed that they were all porticos _in antis_, connected with the main building by solid walls--that the great central column-cluster was surrounded on all sides by a wall of a very massive description, from the four corners of which similar barriers were carried down to the edge of the terrace, abutting in front upon the steps of the great sculptured staircase, and extending eastward and westward, so as to form the antce of an eastern and a western portico. In the two corners between the northern in _antae_ of the side porticos and the _antae_ of the portico in front are supposed to have been large guard-rooms, entirely filling up the two angles. The whole building is thus brought into close conformity with the “Palace of Xerxes,” from which it is distinguished only by its superior size, its use of stone pillars, and the elongation of the tetrastyle chambers at the sides of that edifice into porticos of twelve pillars each.