za. To 12 parts of this
mixture 3 parts of the kaolinic clay of Vicenza were to be added, and
the pieces glazed with a lead glaze, or sometimes with the tin-enamel of
the Italian faience maker. We are in the presence, therefore, of a
material unlike Chinese porcelain in every respect, the Florentine
porcelain being the first of a long line of European porcelains the
artistic qualities of which were obtained by mixing a large quantity of
glass with a small quantity of clay, so that they may almost be regarded
as a species of glazed and painted glass. The technical methods used in
their manufacture and decoration, however, were those of the potter and
not of the glass maker.

With the death of Francesco de' Medici in 1587 it seems probable that
this wonderful innovation came to an untimely end, and we hear no more
of porcelain in Italy for more than a century. During this century
(1587-1687) there can be no doubt that efforts were made all over Europe
to discover the secret of porcelain manufacture; but the first reliable
date we can point to is 1673, when Louis Poterat, a faience maker of
Rouen, obtained a privilege from the French king for the manufacture of
porcelain in that town. The Rouen porcelain in turn ceased with the
death of Poterat in 1696. Authentic specimens are extant in the shape of
salt-cellars, mustard pots and some few vases, the latter of
considerable size. The pieces are usually decorated in blue with
patterns in the Rouen style and were evidently painted by an expert
faience painter. In composition, the porcelain of Rouen, like that of
Florence, was of the artificial or glassy type, and shortly afterwards a
similar ware made its appearance at the faience works of St Cloud near
Paris, and at various works in the city of Paris. Well-known pieces,
bearing the marks here shown, formerly supposed to be the earliest
specimens of French porcelain and the work of Poterat at Rouen, are
probably experimental pieces made in Paris after the date of Poterat's
discovery, as they differ in important particulars from his ware.

[Illustration: Paris Potters' marks.]

[Illustration: St Cloud Potters' marks.]

Once firmly established in France, this manufacture, under the patronage
of the French court or of some great French noble, rapidly assumed a
position of importance. The works at St Cloud received letters-patent
from Louis XIV. in 1696, and the manufacture was continued there down to
1773. The appearance of t