The cornices of the interior, which really formed walks for the lamplighters, are made up of no regular combination of curves; they project steeply forward, the general slanting plane being little disturbed (A, Fig. 60); they are decorated with rows of acanthus, the curved tips of which catch the light in bright points. The cornice of aisle is given at B. We also give a profile of the door-head, which shows how the mouldings conform to a plane of least labour (C). By the jambs and heads being mitred together, the difficulty of working stop ends was also obviated. The mouldings are not sharp and accurate, as is suggested by Salzenberg’s engravings. [Illustration: FIG. 61.--Closures between Pillars, Front of Gynaeceum.] We may mention here that all the doors entering the church from the narthex have raised marble thresholds, that of the Royal Door being a magnificent piece of verde antique which rises some seven inches above the level of the floor; the others are of white marble. _Windows, &c._--The pierced lattices of the windows also furnish examples of another beautiful method of marble slab construction. The large windows are subdivided by marble posts, between which the pierced lattices make a mere screen. Salzenberg, who found a store-room full of broken fragments, gives a section of a bar. Windows over the western entrances, and another at the foot of the south-west stair, which are similarly pierced out of sheet marble, have a simple meander carved on the bars (Fig. 62); this we suppose to be of the ninth or tenth century. The lower part of the window openings going down to the floors are filled with marble closures, some of which bear flat sculptured devices, such as a fish in a lozenge, and on the outside a cross; above this came a second tier of slabs pierced with square openings, which were possibly covered by marble slabs as opening casements. [Illustration: FIG. 62.--Marble Window Lattice.] Some of these closures are translucent; one in the West Gallery over narthex is the well-known “Shining Window” which is mentioned by Grelot. These transparent slabs of “Phengites” were much used in Byzantine architecture. The transparent marble slab windows of S. Miniato are well known. At Ravenna there is a sculptured slab altarfront, through which shone the light of candles placed behind. [Illustration: FIG. 63.--Cipollino Slabs with Cross.] Placed against the east side of the marble screen now in south gynaeceum are slabs of cipollino, which bear large crosses standing on circles; the relief being very slight and the edges softened these show in the faintest way; each cross extends over two slabs, the joint being down the middle. A similar slab with a cross is now placed in the opening on south side of bema. These cross slabs some seven feet high are beautiful examples of the proper use of marble. (Fig. 63.) [Illustration: FIG. 64.--Forms on Carved Impost Moulding.]