The sarcophagus in "Campbell's Tomb" is protected by a plain cylindrical vault of four courses (see Fig. 200, vol. i.), which covers a polygonal vault formed of three large slabs. Both vaults are pierced by a narrow opening, which may, perhaps, have been intended to allow the scents and sounds of the world above to reach the occupant of the sarcophagus. Its arrangement is so careful that it must have had some important purpose to fulfil. In the group of ruins which surrounds the back parts of the Ramesseum (see p. 379, vol. i.) there are vaults of various kinds. A few verge slightly towards the pointed form (see Fig. 47), others are elliptic (Fig. 48). The latter are composed of four courses, and their inner surfaces show a curious arrangement of the bricks; their vertical joints are not parallel to either axis of the vault. The ends of the courses are slightly set off from its face (see Fig. 48). [Illustration: FIG. 46.--Arch in El-Assassif, restored from the plans and elevations of Lepsius.[82]] [82] _Denkmæler_, part i. pl. 94. A tomb near the _Valley of the Queens_, at Thebes, has a strongly marked elliptical vault (Fig. 49).[83] [83] RAMÉE, _Histoire générale de l'Architecture_, vol. i. p. 262. Finally, the inverted segmental arch is not unknown. It is found employed in a fashion which, as described by Prisse, made a great impression upon Viollet-le-Duc. "The foundations of certain boundary walls," says the former, "are built of baked bricks to a height of one-and-a-half metres (about four feet ten inches) above the ground. The bricks are thirty-one centimetres (about twelve-and-a-quarter inches) long, and the courses are arranged in a long succession of inverted segmental arches."[84] [84] PRISSE, _Histoire de l'Art Égyptien_, p. 174.--MARIETTE (_Voyage dans la Haute-Égypte_, vol. ii. pp. 59-60) was struck by a similar arrangement. "Murray's Guide," he says, "tells us, in speaking of Dayr-el-Medineh, that the walls which inclose the courts of this temple present a striking peculiarity of construction. Their bricks are laid in concave-convex courses which rise and fall alternately over the whole length of the walls." This curious arrangement deserved to be noticed, but Dayr-el-Medineh is not the only place where it is to be found. The bounding wall of the temple of Osiris at Abydos affords another instance of it. It should also be noticed that the problem offered to us by such a mode of building is complicated by the fact that, in the quay at Esneh and in some parts of the temple of Philæ, it is combined with the use of very large sandstone blocks. [Illustration: FIG. 47.--Vaults in the Ramesseum.] [Illustration: FIG. 48.--Vault in the Ramesseum; compiled from the data of Lepsius.]