to belong to this class: a ground of gray or white marble slabs
with large panels of colored marble, mosaic bands of geometrical pattern
let into the marble, and sometimes a plain framework of one member with
a carved row of conventional leaves. In Palermo a grayish veined Greek
marble similar to that used in Venice and Ravenna was almost exclusively
used as a background. It formed a most admirable setting for the inlaid
marble mosaics which were laid in rebated panels in the marble slabs,
making a perfectly smooth surface. In the floor mosaics green serpentine
and red or purple porphyry are the usual colors besides the gray, while
brighter reds, gold, blues, white, and a variety of other glasses
(_smalti_) are employed with the serpentine and porphyry in the mosaics
on walls, pulpits, and screens.

In all of the work referred to above, the separate pieces of marble or
glass are carefully shaped to fit the patterns they are intended to
form, and in this respect differ from the Byzantine and other wall
mosaics, and from the earlier Roman mosaic pavements such as those which
are familiar in the Pompeiian buildings. In the latter the shape and
often the size of the pieces making up the pattern were of comparatively
little importance, and the pieces were imbedded in a matrix which filled
up the interstices and gave a background of neutral color.

The marble pavements, made up of discs, squares, and other geometrical
forms of colored marbles surrounded by bands or borders of a smaller
scale, were similar in design to some of the mosaics shown in our
plates. This work is known as Opus Alexandrinum and is familiar from the
pavements of St. Mark's and the church of Santa Maria dei Miracoli in
Venice.

[Illustration: LXV. Ambo in the Capella Palatina, Palermo,
Sicily.]

The Capella Palatina was built and dedicated to St. Peter by King Roger
the Second of Sicily. It must have been begun soon after Roger's
coronation, and was finished in the year 1143.

It is of the same period as the cloister of Monreale, which was
described and illustrated in the March number of THE BROCHURE SERIES;
and the work here shown distinctly recalls the mosaics upon the twisted
columns in this cloister.

The interior is famous as one of the most beautiful works of color
decoration extant. Its general tone is bluish green with mosaic walls
and floor and a wooden ceiling decorated in tempera with cufic
inscriptions. It is scantily lighted