The early Egyptians possessed no engines calculated to make an impression on very massive walls. They knew of but three ways of forcing a stronghold; namely, scaling the walls, sapping them, or bursting open the gates. The plan adopted by their engineers in building the second fort is admirably well calculated to resist each of these modes of attack (fig. 26). The outer walls are long and straight, without towers or projections of any kind; they measure 430 feet in length from north to south, by 255 feet in width. The foundations rest on the sand, and do not go down more than a foot. The wall (fig. 27) is of crude brick, in horizontal courses. It has a slight batter; is solid, without slits or loopholes; and is decorated outside with long vertical grooves or panels, like those depicted on the stelae of the ancient empire. In its present state, it rises to a height of some thirty-six feet above the plain; when perfect, it would scarcely have exceeded forty feet, which height would amply suffice to protect the garrison from all danger of scaling by portable ladders. The thickness of the wall is about twenty feet at the base, and sixteen feet above. The top is destroyed, but the bas-reliefs and mural paintings (fig. 28) show that it must have been crowned with a continuous cornice, boldly projecting, furnished with a slight low parapet, and surmounted by battlements, which were generally rounded, but sometimes, though rarely, squared. The walk round the top of the ramparts, though diminished by the parapet, was still twelve or fifteen feet wide. It ran uninterruptedly along the four sides, and was reached by narrow staircases formed in the thickness of the walls, but now destroyed. There was no ditch, but in order to protect the base of the main wall from sappers, they erected, about ten feet in advance of it, a battlemented covering wall, some sixteen feet in height. These precautions sufficed against sap and scaling; but the gates remained as open gaps in the circuit. It was upon these weak points that besiegers and besieged alike concentrated their efforts. The fortress of Abydos had two gates, the main one being situate at the east end of the north front (fig. 29). A narrow cutting (A), closed by a massive wooden door, marked the place in the covering wall. Behind it was a small _place d'armes_ (B), cut partly in the thickness of the wall, and leading to a second gate (C) as narrow as the first. When, notwithstanding the showers of missiles poured upon them from the top of the walls, not only in front, but also from both sides, the attacking party had succeeded in carrying this second door, they were not yet in the heart of the place. They would still have to traverse an oblong court (D), closely hemmed in between the outer walls and the cross walls, which last stood at right angles to the first. Finally, they must force a last postern (E), which was purposely placed in the most awkward corner.