the
plastic state into an embossed plaster mould, the pattern or design on
the mould being raised. When the tile is withdrawn from the mould, the
outline of the pattern is indented, and the indented parts are filled
in with colored liquid clays, according to the colors it is desirable
to produce. The surface is then scraped quite flat, until the pattern
appears well defined. The tile is then heated, or as it is termed,
fired, which brings out the colors to the proper tint.
The
Venetian tiles and mosaics are produced by the com pression of powdered
clays into metal dies, of any geometrical form that may be devised,
the clays having been previously stained with metallic colors. Each
tile or tessera is, of course, of the same color throughout.
When fired, they are arranged on a smooth platform, with the faces
downward, according to the design intended, after which liquid Roman or
Portland cement is poured upon them, and they are thus formed into
slabs of any size required.
The
Alhambra or Spanish tiles are made by pressing plastic clays into an
embossed mould, which forms grooves or indentations; these tiles are
then fired, and come out of the oven with the pattern formed. The
indentations are then filled in with enamels of various colors and
fired again, which produces a brilliant effect, and renders the tiles
suitable either for floors or the interior walls of buildings.
A mosaic pavement, composed of tesserce of
vitrified clay, of several colors and shapes, all produced by machinery
with great rapidity, and without the necessity of chipping any of the tesserce, and
at the same time making an endless variety of patterns, is produced in
England, in the following manner: The clay being prepared in the usual
way, by washing and sifting, and stained with various metallic oxides
(oxide cobalt, blue smalts, manganese, zaffre, red lead, crocus mart
is, an rum musivum, oxide chrome, coppei
