The
Circle
Diaper, Scale Diaper,
&c-
281
In the
Arabian and
the Moorish styles, incrustations of Mosaics
in
stone and
glazed
terracotta were a popular method of wall-decoration.
The art
of
mosaic has never
acquired a firm footing in
northern
countries.
Plate
172. The Circle Dl^er,
&c.
1.
Mosaic,
cathedral, Monreale, Sicily
2.
Arabian
mosaic,
stucco on stone, (Prisse d'Avennes).
3.
Roman
mosaic.
4.
Marble
mosaic,
windows,
cathedral, Florence, (Hessemer).
5.
Geometrical
pattern, Sta. Croce,
Florence.
6.
Marble
mosaic, San Vitale,
Ravenna,
(Hessemer).
7.
Modem
tesselated mosaic, Sorrento.
8
and
10. Moorish
mosaic, Ambassadors' Hall, Alhambra, Granada,
(Owen
Jones).
9.
Ai-abian
mosaic, stucco on
stone,
(Prisse d'Avennes).
The
Scale
Diaper.
&c.
(Enamel.) (Plate
173.)
AVhere
the
surfaces of
metal utensils and vessels are
to
receive
a
flat
decoration
this
is usually effected by engraving,
etching,
dam-
askeening,
enamel,
or
niello work.
In the process
of Engraving, the
decoration
is engraved
by means
of the graving-tool, and the hollows
in
some
cases filled
up
with
coloui-ed lacquer,
&c.
In Etching, the
metallic
surface
is
protected
against the action of the etching-fluid
by being
coated with
a
film,
so that the design is sunk where the
protecting
film
is removed
by the
Artist. In
Damaskeening, the pre-
cious metals
are fastened
on
iron
and steel,
by
being
hammered into
engraved
hollows
which
have been
undercut with a
roughened ground.
The
processes
of Enamelling
are very various. In the cloison process:
bent
bands
or fillets
of metal
(cloisons)
are
soldered-on
to
the metal
ground,
and
the
hollows
or cells thus formed
are
filled
with pulve-
rised
glass
paste
(glass
coloured with
metallic oxides)
which
are then
vitrified
by heat.
In
the sunk
or "cbamp-lev6" process:
the
hollows
in the
metallii
ground
are
produced by the
graver,
or by
casting
and
subsequent
chasing, and are
then
filled with
enamel. Niello
resembles
black
enamel:
the
enamel paste
being replaced by
a com'
position
of metal
and sulphur.
Enamel
work (sunk
-work) was known in Antique
times.
The
Cologne
enamel
was
celebrated
in
the Middle Ages.
Cloison
en.amel
Las
been
practised in
the
East, in
China, and in
Japan, from the
earliest
times.
The so-called
Limoges "enamel" is
painted on
a
plain
metal
ground,
without any
previous cloispns
or
any sunk
-fields
for