The principal entrance of the palace is the north gate (Plate 11, Fig. 1). Before the door there is an artificial platform thirty-two paces from north to south by eighty-seven paces from east to west. The door is placed in a rectangular tower, 15·70 metres wide, which projects 5·10 metres from the face of the wall, 2·40 metres from the face of the towers. Between the west side of the gate-tower and the first of the western round towers is stretched a vault 2·50 metres in depth (Plate 11, Fig. 2). Upon this vault rests a small platform, immediately below the loopholes of the chemin de ronde, at the level of the second story. On the east side of the gate-tower there are traces of a similar vault, but this must have fallen at a period when the palace was still inhabited, since the place which it occupied upon the wall has been carefully plastered over. The pointed arch over the north door is a later reconstruction. The door leads into a narrow room, No. 1, 5·95 metres by 3 metres, from which there is access to rooms 2 and 3. These rooms are irregular in shape, unlighted, and built over vaults which are now filled with débris. The authors of _Ocheïdir_ suggest that they may have gone down to the water-level. I doubt it. The water-level in the palace yard is considerably deeper than these vaults are likely to have been, and the water there is too brackish to drink. It is more likely that these subterranean chambers were dungeons. The vault over room 1 is not continuous. It is composed of a series of seven transverse arches, ·65 metre wide, separated by spaces ·20 metre wide (Plate 12, Fig. 1). These apertures enabled the occupants of room 88, on the first floor, to pour boiling liquids on any foe who had passed through the door. Room 1 is bounded to the south by an arched doorway, oversailing the wall, as is the case with all wide arched openings at Ukhaiḍir, beyond which lies the smaller chamber No. 4, 4·15 metres long by 3·10 wide. A transverse arch cuts off 1·05 metres of this space, leaving a square of 3·10 metres to be covered by a fluted dome (Plate 13, Fig. 1).[16] The remaining three sides of the chamber are broken by pointed archways which give access to the great hall (No. 7), and to the passages Nos. 5 and 6. The fluted circle of the dome is set upon a fillet which has a projection of about 1 centimetre from the face of the wall below (Plate 13, Fig. 2). The circle is accommodated to the square by a course of stones forming at each corner a flat triangular bracket, rounded upon the inner side. The upper part of the dome is much ruined. The curve must have been ovoid and it is probable that an aperture was left at the summit, since the dome, if closed, would have projected considerably above the floor level of room 88. The hole in the upper floor, like the slits in the roof of room 1, would have served for purposes of attack when the enemy had forced an entrance.