re made, as well as
those with heavy bosses or gadroons imitated from embossed metal
forms. It is interesting, though not surprising, to note that for the
fine later wares, the roughly thrown vases, when sufficiently dry,
were recentred on the wheel or were placed in a joiner's lathe and
smoothed to a clean and accurate surface. The Greek potters did the
same, and this practice must always be followed where fine painting or
gilding is afterwards to be applied. In the later florid vases of the
Urbino style the piece was built up of thrown parts and moulded parts
(handles, masks, spouts, &c.), luted together with slip when they were
dry enough to be safely handled, and then retouched by the modeller or
vase-maker, a method followed to this day for elaborate pieces of
pottery or porcelain.

[Illustration: PLATE V.

Rhodian or Turkish: 16th century.

Syro-Persian: 13th century.

Rhodian or Turkish: 16th century.

Rhodian or Turkish: 16th century.

Damascus: 16th century.

Persian, lustre and underglaze colour: 13th century.]

3. _The Glaze._--The white enamel which formed at first both the glaze
and the ground for painting upon--_bianco_, as it was called--was
prepared in a complicated way. A clear potash glass (_marzacotto_) was
made by melting together clean siliceous sand (_rena_) and the potash
salt left as the lees of wine (_feccia_). This corresponds to the
alkaline glaze of the Egyptians with the substitution of potash for
soda. Such a glaze alone would have been useless to the Italian
potter, and accordingly the _bianco_ was made by melting together
thirty parts of _marzacotto_ and twelve parts of lead and tin ashes.
The white enamel as used was therefore a mixed silicate of lead and
potash rendered opaque with oxide of tin.

4. Pigments (_colori_) were compounded from metallic oxides or earths;
the yellow, from antimoniate of lead, which was mixed with oxide of
iron to give orange; the green, from oxide of copper (the turquoise
tint given to the Egyptian and Syrian glazes by oxide of copper is
impossible with a glaze of lead and tin); and the greens were made by
mixing oxide of copper with oxide of antimony or oxide of iron; blue,
from oxide of cobalt, used in the form of a blue glass (_smalto_, or
_zaffara_); brownish-purple, from manganese; black, from mixtures of
the other colours; and the rare red, or reddish br