the gridiron is of the proportions of a cot bedstead, and has a raging
fire beneath it,--a gruesome suggestion of the martyrdom.

No finer examples of the art of the colourist in mosaic can be
seen than in the procession of Virgins at San Apollinaire Nuovo
in Ravenna. Cool, restrained, and satisfying, the composition has
all the elements of chromatic perfection. In the golden background
occasional dots of light and dark brown serve to deepen the tone
into a slightly bronze colour. The effect is especially scintillating
and rich, more like hammered gold than a flat sheet. The colours
in the trees are dark and light green, while the Virgins, in brown
robes, with white draperies over them, are relieved with little
touches of gold. The whole tone being thus green and russet, with
purplish lines about the halos, is an unusual colour-scheme, and
can hardly carry such conviction in a description as when it is
seen.

In the East, the Church of Sta. Sophia at Constantinople exhibited
the most magnificent specimens of this work; the building was
constructed under Constantine, by the architects Anthemius and
Isidore, and the entire interior, walls and dome included, was covered
by mosaic pictures.

Among important works of the seventh century is the apse of St.
Agnese, in Rome. Honorius decorated the church, about 630, and it
is one of the most effective mosaics in Rome. At St. John Lateran,
also, Pope John IV. caused a splendid work to be carried out,
which has been reported as being as "brilliant as the sacred waters."

In the eighth century a magnificent achievement was accomplished