thern European potter
of the period from the 6th to the 12th century had to build up his
methods afresh, and improved kilns were invented. The general type of
medieval potter's kiln is illustrated for us in the manuscript of an
Italian potter of the 16th century, now in the library of the Victoria
and Albert Museum[3] (fig. 5). Kilns of a different type, horizontal
reverberatory kilns, were used for making the hard-fired pottery of
Europe (Rhenish stoneware, &c.), as well as for Chinese porcelain and
the earliest German porcelains. With the organization of pottery as a
factory industry in the 18th century, improved kilns were introduced,
and the type of kiln now so largely used in civilized countries is
practically a vertical reverberatory furnace of circular section, from
10 to 22 ft. in diameter and of similar height, capable, therefore, of
containing at one firing a quantity of pottery that would have formed
the output of a medieval potter for a year. Every device that can be
thought of for the better utilization of heat and its even
distribution throughout the kiln or oven has been experimented with;
and, though the results have been most successful from the point of
view of the potter, even the most recent coal-fired ovens remain very
wasteful types of apparatus, the amount of available heat being
relatively small to the fuel consumption. Gas-fired kilns and ovens
are now being used or experimented with in every country, and their
perfection, which cannot be far distant, will improve the most vital
of the potter's processes both in certainty and economy.

[Illustration: FIG. 5.--Two forms of Italian potter's wheels, about
1540.]

_Glazes._--We are never likely to known when glaze (i.e. a coating of
fired glass) was first applied to pottery, though the present state of
knowledge would incline us to the opinion that the earliest glazed
objects we possess are those of ancient Egypt,[4] but the practice may
have been originated independently wherever a knowledge of the
elements of glass-making had spread, as all the early glazes were of
the alkaline type, which must first be fused into a glass before they
can be applied to pottery.

Many primitive races seem to have burnished their pottery after it was
fired, in order to get a glossy surface; and in other cases the
surface was rendered shining and waterproof by coating it with waxy or
resinous