difficult because the angle of the wall is ruined. The next tower lies 5·65 metres to the north of the first; an interval of 7·35 metres separates it from the third tower, and the third tower is 10·70 metres from the larger tower at the north-west angle of the court. The angle tower contains a winding stair. The three smaller towers seem to be a later addition to the wall; they bear no relation to the three doors, and they block some of the windows. The windows are placed in groups of three, two groups between the south-west angle and the first door, one group between the first and second, and the second and third doors, and two groups between the third door and the angle tower. There are traces of a similar group in the north wall immediately to the east of the angle tower, and the straight face at the east end of the north wall gives reason to believe that there was a group of windows here also. The north wall is much ruined, and the ruin heaps are covered with blown sand. The arches of the windows are carried by engaged columns.[32] To the north of room 158, and in a line with it, lie nine vaulted chambers which were added at a later date (Plate 44, Fig. 2). They are separated from No. 158 by a stair running up to the roof, with a doorway to the west. At the east end there is a small room under the top of the stair with a loophole window in the east wall. From this room, which is accessible from No. 159, a stair, now completely ruined, led down into a substructure. Nos. 159 and 160 are 4 metres broad; they are covered by barrel vaults and have a door at either end. No. 161 opens by two doors into No. 162. No. 162 is 4·80 metres broad and is divided across the centre by a transverse arch. East of the transverse arch only half the space is vaulted over. Besides the doors, there are two small windows high up in the north and south wall. In the east and west walls there is a wide archway instead of the usual doors. The five rooms 163-167 resemble in all respects Nos. 159-161. Except over No. 162, where the vault is higher than in the other chambers, the roof of rooms 154-167 is raised above small compartments lying over the barrel vaults (Plate 42, Figs. 2 and 3), and the mass of masonry between the vaults was lightened in the same manner. Slit-like windows appear high up in the east wall between the vaults (not, however, in rooms 153-162), doubtless in connexion with these compartments.