[Illustration: FIG. 157.--_Claustra_ in the Hypostyle Hall of the Temple of Khons. Compiled from the elevations in the _Description_, iii. 28.]
The use of these _claustra_, full of variety though they were in the hands of a skilful architect, were not the only methods of lighting their temples to which the Egyptians had recourse. They were helped in their work, or, in the case of very small chambers, replaced, by oblique or vertical openings contrived in the roof itself. These oblique holes are found in the superior angles of the hypostyle hall at Karnak (Fig. 159). After the roof was in place it was seen, no doubt, that the _claustra_ did not of themselves give enough light for the huge chamber, and these narrow openings were laboriously cut in its ceiling. One of the inner chambers of the Temple of Khons is feebly lighted by vertical holes cut through the slabs of the roof (Fig. 160). Similar openings are to be seen in the lateral aisles of the hypostyle hall in the Ramesseum. The slight upward projection which surrounds the upper extremities of these holes should be noticed (Fig. 161). Finally there are buildings in which these openings are the only sources of illumination. This is notably the case in the Temple of Amada. The upper part of our plan (Fig. 162) represents the roof of that temple and the symmetrically arranged openings with which it is pierced.
[Illustration: FIG. 158.--Method of lighting in one of the inner halls of Karnak. Compiled from the plans and elevations of the _Description_.]
[Illustration: FIG. 159.--Auxiliary light-holes in the Hypostyle Hall at Karnak. _Description_, iii. 26.]
[Illustration: FIG. 160.--Method of lighting one of the rooms in the Temple of Khons. _Description_, iii. 55.]
[Illustration: FIG. 161.--Light openings in a lateral aisle of the Hypostyle Hall in the Ramesseum. From a photograph.]
The Ptolemaic Temple of Edfou is much more generously treated in the matter of light. Its flat roof is pierced by two large rectangular openings resembling the _compluvium_ of a Pompeian house, and making it, in a certain sense, hypæthral. No example of such an arrangement has been met with in the Pharaonic temples. It is possible that its principle was directly borrowed from the Greeks. It is hardly so consistent with the national ideas and traditions as the _claustra_.