The causes that have led to the widespread use of symmetrical forms
are difficult to understand. Symmetrical motions of the arms and hands
are physiologically determined. The right and left are apt to move
symmetrically and the motions of the same arm or of both arms are
often performed rhythmically and symmetrically from right to left and
from left to right. I am inclined to consider this condition as one of
the fundamental determinants, in importance equal to the view of the
symmetry of the human body and of that of animals; not that the designs
are made by right and left hand, rather that the sensation of the
motions of right and left lead to the feeling of symmetry.
[Illustration: Fig. 22. Australian shields.]
[Illustration: Fig. 23. Paleolithic paintings.]
In by far the greatest number of cases symmetrical arrangements are to
the right and left of a vertical axis, much more rarely above and below
a horizontal one.
The prevalence of horizontal and the rarity of vertical symmetry
is presumably due to the absence of vertically symmetrical
movements,—except in those rhythmic movements in which the arms are
alternately raised and lowered,—and in the rarity of natural forms
that are vertically symmetrical.
In nature we see generally more fundamental differences in vertical
direction than in horizontal layers. In animals, legs, body and head
are on different levels. In landscapes, earth, trees, mountains and
sky follow one another in vertical succession. On the other hand, we
are liable to find in horizontal sequence sameness or variations of
analogous form. This may be one of the reasons why there are found in
ornamental art frequent arrangements in a series of horizontal bands
that differ fundamentally in pattern, while in each horizontal band we
find either symmetry, rhythmic repetition, or variations of similar
forms (figs. 24, 25, 26). Exceptions however, occur, for instance in
the decorations of Melanesian houses (Plate III).
Other causes may contribute to the development of symmetrical patterns.
In the making of coiled pottery or coiled basketry symmetry results
from the process of manufacture. By regular turning of the pot or
basket a circular form is produced. The process of winding twine around
a holder may have the same effect. In two-handed implements, such as
the bow of the bowdrill, symmetrical forms also develop, but implements
of this type are not by any means numerous and their occurrence is no
adequate explanation of the general occurrence of symmetry.
We must leave it undecided whether the circumstances here referred to
are adequate to account for the symmetry of form of such implements
as lance heads, arrow-heads, baskets and boxes. We must be satisfied
with the establishment of their general occurrence and the knowledge
that they have an esthetic value wherever they are found. Examples of
symmetrical arrangements are very numerous. The boxes from British
Columbia (fig. 274, p. 263), neckrests of the Kaffers (fig. 9, p.
23), Melanesian shields and paddles (fig. 10, p. 25), and the painted
rawhides of the Sauk and Fox (figs. 13-15, pp. 27, 28) may serve
as exemples. A special type of symmetrical design is found in our
heraldic style with its animals rampant on each side of a central
field. It is interesting to note that the same arrangement is very
ancient. It occurs on the Lions’ Gate of Mycenae. It has also developed
independently in prehistoric Peru (fig. 27).
[Illustration: PLATE III.