s increased with the introduction of the sheep, which
furnishes fuel for the burning, and the horse, before unknown, has
facilitated transportation, whereby trade for this class of basketry
with the distant nomadic tribes who still make it is rendered easy.
Withal, however, the quality of pottery has not improved, but has
deteriorated; as sheep-dung is but an inferior fuel for firing.

EVOLUTION OF FORMS.

[Illustration: FIG. 523.--Food trencher of wicker-work.]

[Illustration: FIG. 524.--Latter inverted, as used in forming bowls]

Bearing these statements in mind, the discussion of the evolution as
well as of the distribution of form, and later of the evolution of
decoration, in pottery will become easier. By lingering steps there
was early developed a method of building up vessels by a process
differing in part from the spiral. As the parching-bowl had been
evolved from the roasting-tray, so, we may infer, the food-bowl was
suggested by the hemispherical food-trencher of wicker-work. (See Fig.
523.) Yet, curiously enough, the inside of the latter seems not at
first to have been used in molding the food-bowl, as, it will be
remembered, the tray had been in forming the parching-pan. On the
contrary, the clay was coiled around and around the _outside_ of the
bottom of an inverted basket bowl (see Fig. 524), instead of being
pressed evenly into it. As with the cooking pot, so with this; as the
coiling progressed it was corrugated, not so much, however from
necessity, as from habit. In consequence of the difficulty experienced
in removing these bowl-forms from the bottoms of the baskets--which
had to be done while they were still plastic, to keep them from
cracking--they were made very shallow. Hence the specimens found among
the older ruins and graves are not only corrugated outside, but are
also very wide in proportion to their height. (See Fig. 525.) As time
went on it was found that bowls might be made deeper, and yet readily
be taken off from the basket bottoms, if slightly moistened outside
and pressed evenly all around, or, better still, scraped; for, being
plastic, this proceeding caused them to grow thinner, consequently
larger, thereby to loosen from the basket over which they had been
molded. As a result of this scraping, however, the corrugated surface
was destroyed, nor could it easily be restored. Therefore bowls when
made deep were, as a rule, smooth on the outside as well as on the
interior surf