y an original for the dipper
form in clay as is the gourd or the conch shell; the familiar horn
vessel of the western tribes, Fig. 468, _a_, would have served equally
well. The specimen given in _b_ is from Arkansas. As a rule, however,
such vessels cannot be traced to their originals, since by copying and
recopying they have varied from the parent form, tending always toward
uniform conventional shapes.

A vessel of rectangular outline might originate in wood or bark. In Fig.
469, _a_, we have a usual form of bark tray, which is possibly the
prototype of the square-rimmed earthen vessel given in _b_.

[Illustration: _a_, Wicker. _b_, Clay. FIG. 470.--Form
originating in basketry.]

[Illustration: _a_, Wicker. _b_, Clay. FIG. 471.--Form
originating in basketry.]

[Illustration: _a_, Net. _b_, Clay. FIG. 472.--Form originating
in basketry.]

Basketry and other classes of woven vessels take a great variety of
forms and, being generally antecedent to the potter's art and constantly
present with it, have left an indelible impression upon ceramic forms.
This is traceable in the earthenware of nearly all nations. The clay
vessel is an intruder, and usurps the place and appropriates the dress
of its predecessor in wicker. The form illustrated in Fig. 470, _a_, is
a common one with the Pueblo peoples, and their earthen vessels often
resemble it very closely, as shown in _b_. Another variety is given in
Fig. 471, _a_ and _b_. These specimens are from southwestern Utah. Fig.
472, _b_, illustrates a form quite common in the Southern States, a
section in which pouch-like nets and baskets, _a_, were formerly in use
and in which the pots were often modeled.

+INVENTION OF FORM.+

In the early stages of art, forms are rarely invented outright and I
shall not stop to consider the subject here.

+MODIFICATION OF FORM.+

The acquisition of new materials, the development of new uses, the
employment of new processes of manufacture, and many other agencies lead
to the multiplication of forms through modification. The processes by
which highly differentiated forms are reached are interesting throughout
and repay the closest study.

A preliminary classification of the various causes that lead to
modification is given in the following synopsis:

/ / /To assume form.
| |Incapacity of material--\To retain form.