gods, even so the plan of their temples is in such wise devised as to lead gradually from the full sunshine of the outer world to the obscurity of their retreats.  At the entrance we find large open spaces, where air and light stream freely in.  The hypostyle hall is pervaded by a sober twilight; the sanctuary is more than half lost in a vague darkness; and at the end of the building, in the farthest of the chambers, night all but reigns completely.  The effect of distance which was produced by this gradual diminution of light, was still further heightened by various structural artifices.  The parts, for instance, are not on the same level.  The ground rises from the entrance (fig. 80), and there are always a few steps to mount in passing from one part to another.  In the temple of Khonsu the difference of level is not more than 5-1/4 feet, but it is combined with a lowering of the roof, which in most cases is very strongly marked.  From the pylon to the wall at the farther end, the height decreases continuously.  The peristyle is loftier than the hypostyle hall, and the hypostyle hall is loftier than the sanctuary.  The last hall of columns and the farthest chamber are lower and lower still.  The architects of Ptolemaic times changed certain details of arrangement.  They erected chapels and oratories on the terraced roofs, and reserved space for the construction of secret passages and crypts in the thickness of the walls, wherein to hide the treasure of the god (fig. 81).  They, however, introduced only two important modifications of the original plan.  The sanctuary was formerly entered by two opposite doors; they left but one.  Also the colonnade, which was originally continued round the upper end of the court, or, where there was no court, along the facade of the temple, became now the pronaos, so forming an additional chamber.  The columns of the outer row are retained, but built into a wall reaching to about half their height.  This connecting wall is surmounted by a cornice, which thus forms a screen, and so prevented the outer throng from seeing what took place within (fig. 82).  The pronaos is supported by two, three, or even four rows of columns, according to the size of the edifice.  For the rest, it is useful to compare the plan of the temple of Edfu (fig. 83) with that of the temple of Khonsu, observing how little they differ the one from the other.

[Illustration:  Fig. 83.—­Plan of temple, Edfu.]

[Illustration:  Fig. 84.—­Plan of the temple of Karnak in the reign of Amenhotep III.]

[Illustration:  Fig. 85.—­Plan of Hypostyle Hall, Karnak.]

[Illustration:  Fig. 86.—­Plan of great temple, Luxor.]

[Illustration:  Fig. 87.—­Plan of the Isle of Philae.]