| |Incapacity of the artisan.
| |Changes in method of manufacture.
|By adventition--|Changes in environment.
|Changes of use.
Modification of form--| |Lack of use.
| \Influence of new or exotic forms, etc.
|
| /To enhance usefulness.
|By intention--|
| \To please fancy.--/For the beautiful.
\ \For the grotesque.

+MODIFICATION BY ADVENTITION.+

_Incapacity of material._--It is evident at a glance that clay lacks the
capacity to assume and to retain many of the details of form found in
antecedent vessels. This necessarily results in the alteration or
omission of these features, and hence arise many modifications of
original forms.

The simple lack of capacity on the part of the potter who undertook to
reproduce a model would lead to the modification of all but the most
simple shapes.

The acquisition of the art by a superior or an inferior race, or one of
different habits would lead to decided changes. A people accustomed to
carrying objects upon the head, on acquiring earthen vessels would shape
the bases and the handles to facilitate this use.

Improvements in the methods of manufacture are of the greatest
importance in the progress of an art. The introduction of the lathe, for
example, might almost revolutionize form in clay.

As arts multiply, clay is applied to new uses. Its employment in the
manufacture of lamps, whistles, or toys would lead to a multitude of
distinct and unique forms.

The acquisition of a new vessel-making material by a nation of potters
and the association of the forms developed through its inherent
qualities or structure would often lead ceramic shapes into new
channels.

[Illustration: _a_, wood. _b_, clay. FIG. 473.--Coincident forms.]

The contact of a nation of potters with a nation of carvers in wood
would tend very decidedly to modify the utensils of the former. One
example may be given which will illustrate the possibilities of such
exotic influences upon form. In Fig. 473, _a_, we have an Alaskan vessel
carved in wood. It represents a beaver grasping a stick in its hands and
teeth. The conception is so unusual and the style of vessel so
character