d was situate
upon a height, the Egyptian engineers knew perfectly well how to adapt
their lines of defence to the nature of the site. At Kom Ombo (fig. 33) the
walls exactly followed the outline of the isolated mound on which the town
was perched, and presented towards the east a front bristling with
irregular projections, the style of which roughly resembles our modern
bastions. At Kummeh and Semneh, in Nubia, where the Nile rushes over the
rocks of the second cataract, the engineering arrangements are very
ingenious, and display much real skill. Usertesen III. had fixed on this
pass as the frontier of Egypt, and the fortresses which he there
constructed were intended to bar the water-way against the vessels of the
neighbouring negro tribes. At Kummeh, on the right bank, the position was
naturally strong (fig. 34). Upon a rocky height surrounded by precipices
was planned an irregular square measuring about 200 feet each way. Two
elongated bastions, one on the north-east and the other on the south-east,
guarded respectively the path leading to the gate, and the course of the
river. The covering wall stood thirteen feet high, and closely followed the
line of the main wall, except at the north and south corners, where it
formed two bastion-like projections. At Semneh, on the opposite bank, the
site was less favourable. The east side was protected by a belt of cliffs
going sheer down to the water's edge; but the three other sides were well-
nigh open (fig. 35). A straight wall, about fifty feet in height, carried
along the cliffs on the side next the river; but the walls looking towards
the plain rose to eighty feet, and bristled with bastion-like projections
(A.B.) jutting out for a distance of fifty feet from the curtain wall,
measuring thirty feet thick at the base and thirteen feet at the top, and
irregularly spaced, according to the requirements of the defence. These
spurs, which are not battlemented, served in place of towers. They added to
the strength of the walls, protected the walk round the top, and enabled
the besieged to direct a flank attack against the enemy if any attempt were
made upon the wall of circuit. The intervals between these spurs are
accurately calculated as to distance, in order that the archers should be
able to sweep the intervening ground with their arrows. Curtains and
salients are alike built of crude brick, with beams bedded horizontally in
the mass. The outer face is in two parts, the lower