76. The eye, not being held on a vertical axis or on a balance-center,
readily follows any suggestion of movement.
[Illustration: Fig. 97]
In this case there is no intimation of any vertical axis or
balance-center. The figure is consequently unstable. There is a sense
of movement to the right. This is due, not only to the inclinations to
the right, but to the convergences in that direction.
[Illustration: Fig. 98]
In this case the movement is unmistakably to the left. In such cases we
have movement, but no Rhythm.
77. Rhythm requires, not only movement, but the order of regular and
marked intervals.
[Illustration: Fig. 99]
In Fig. 99 we have a line, a linear progression, which gives us the
feeling of movement, unmistakably. The movement, which in the motive
itself is not rhythmical, becomes rhythmical in its repetition at
regular, and in this case equal, intervals. The intervals are marked by
the repetitions.
78. It is a question of some interest to decide how many repetitions
are required in a Rhythm. In answer to this question I should say
three as a rule. A single repetition shows us only one interval, and
we do not know whether the succeeding intervals are to be equal or
progressive, arithmetically progressive or geometrically progressive.
The rhythm is not defined until this question is decided, as it will
be by two more repetitions. The measures of the rhythm might take the
form of a repeated relation of measures; a repetition, for example, of
the measures two, seven, four. In that case the relation of the three
measures would have to be repeated at least three times before the
character of the rhythm could be appreciated.
79. Any contrariety of movement in the motive is extended, of course,
to its repetitions.
[Illustration: Fig. 100]
In this case, for example, there are convergences and, consequently,
movements both up and down. This contrariety of movements is felt
through the whole series of repetitions. Other things being equal, I
believe the eye moves up more readily than down, so that convergences
downward have less effect upon us than corresponding convergences
upward.
[Illustration: Fig. 101]
In this case, by omitting the long vertical line I have diminished the
amount of convergence downward. In that way I have given predominance
to the upward movement. Instead of altogether omitting the long
vertical line, I might have changed its tone from black to gray. That
would cause an approximate instead of complete disappearance. It should
be remembered that in all these cases the habit of reading comes in to
facilitate the movements to the right. It is easier for the eye to move
to the right than in any other direction, other things being equal.
The movement back to the beginning of another line, which is of course
inevitable in reading, produces comparatively little impression upon
us, no more than the turning of the page. The habit of reading to the
right happens to be our habit. The habit is not universal.
80. Reading repetitions and alternations to the right, always, I, for
a long time, regarded such repetitions and alternations as rhythmical,
until Professor Mowll raised the question whether it is necessary
to read all alternations to the right when there is nothing in the
alternations themselves to suggest a movement in one direction rather
than another. Why not read them to the left as well as to the right?
We at once decided that the movement in a Rhythm must be determined
by the character of the Rhythm itself, not by any habit of reading,
or any other habit, on our part. It was in that way that we came
to regard repetitions and alternations as illustrations of Harmony
rather than of Rhythm. Rhythm comes into the Harmony of a Repeated
Relation when the relation is one which causes the eye to move in one
direction rather than another, and when the movement is carried on from
repetition to repetition, from measure to measure.
81. The repetition of a motive at equal intervals, when there is no
movement in the motive, gives us no feeling of Rhythm.
[Illustration: Fig. 102]
In this case, for example, we have a repetition in the line of a
certain symmetrical shape. As there is no movement in the shape
repeated, there is no Rhythm in the repetition. There is nothing to
draw the eye in one direction rather than another. The attractions at
one end of the line correspond with the attractions at the other.
82. The feeling of Rhythm may be induced by a regular diminution of
measure or scale in the repetitions of the motive and in the intervals
in which the repetitions take place.
[Illustration: Fig. 103]
In this case the shape repeated is still symmetrical, but it is
repeated with a gradual diminution of scale and of intervals, by which
we are given a feeling of rhythmic movement. The change of scale and of
intervals, to induce a sense of rhythmic motion, must be regular. To
be regular the change must be in the terms of one or the other of the
regular progressions; the arithmetical progression, which proceeds by
a certain addition, or the geometrical, which proceeds by a certain
multiplication. The question may arise in this case (Fig. 103) whether
the movement of the Rhythm is to the right or to the left. I feel,
myself, that the movement is to the right. In diminishing the scale of
the motive and of the intervals we have, hardly at all, diminished the
extent of the tone-contrast in a given angle of vision. See Fig. 41,
p. 27, showing the increase of attractions from one visual angle to
another. At the same time we come at the right end of the progression
to two or more repetitions in the space of one. We have, therefore,
established the attraction of a crowding together at the right end
of the series. See the passage (p. 43) on the attractiveness of a
line. The force of the crowding together of attractions is, I feel,
sufficient to cause a movement to the right. It must be remembered,
however, that the greater facility of reading to the right is added
here to the pull of a greater crowding together of attractions in the
same direction, so the movement of the Rhythm in that direction may not
be very strong after all. If the direction of any Rhythm is doubtful,
the Rhythm itself is doubtful.
83. The feeling of Rhythm may be induced, as I have said, by a gradual
increase of the number of attractions from measure to measure, an
increase of the extent of tone-contrast.
[Illustration: Fig. 104]
Increasing the extent of tone-contrast and the number of attractions in
the measures of the Rhythm in Fig. 103, we are able to force the eye to
follow the series in the direction contrary to the habit of reading,
that is to say from right to left.
A decrease in the forces of attraction in connection with a decrease
of scale is familiar to us all in the phenomena of perspective. The
gradual disappearance of objects in aerial perspective does away
with the attraction of a greater crowding together of objects in the
distance.
[Illustration: Fig. 105]
In this case the diminution of scale has been given up and there is
no longer any crowding together. There is no chance of this rhythm
being read from left to right except by an effort of the will. The
increase of attractions toward the left is much more than sufficient to
counteract the habit of reading.
84. The force of a gradual coming together of attractions, inducing
movement in the direction of such coming together, is noticeable in
spiral shapes.
[Illustration: Fig. 106]
In this case we have a series of straight lines with a constant and
equal change of direction to the right, combined with a regular
diminution of measures in the length of the lines, this in the terms
of an arithmetical progression. The movement is in the direction of
concentration and it is distinctly marked in its measures. The movement
is therefore rhythmical.
[Illustration: Fig. 107]
In this case we have a series of straight lines with a constant change
of direction to the right; but in this case the changes of measure in
the lines are in the terms of a geometrical progression. The direction
is the same, the pull of concentration perhaps stronger.
[Illustration: Fig. 108]
In this Rhythm there is an arithmetical gradation of measures
in the changes of direction, both in the length of the legs and
in the measure of the angles. The pull of concentration is, in
this case, very much increased. It is evident that the legs may
vary arithmetically and the angles geometrically; or the angles
arithmetically and the legs geometrically.
85. If, in the place of the straight lines, which form the legs, in
any of the examples given, are substituted lines which in themselves
induce movement, the feeling of Rhythm may be still further increased,
provided the directions of movement are consistent.
[Illustration: Fig. 109]
In this case the movement is in the direction of increasing
concentration and in the direction of the convergences.
If the movement of the convergences be contrary to the movement of
concentration, there will be in the figure a contrary motion which
may diminish or even entirely prevent the feeling of Rhythm. If the
movement in one direction or the other predominates, we may still
get the feeling of Rhythm, in spite of the drawback of the other and
contrary movement.
[Illustration: Fig. 110]
In this case the linear convergences substituted for the straight lines
are contrary to the direction of increasing concentration. The movement
is doubtful.
86. Corresponding rhythms, set in contrary motion, give us the feeling
of Balance rather than of Rhythm. The balance in such cases is a
balance of movements.
[Illustration: Fig. 111]
This is an example of corresponding and opposed rhythms producing the
feeling, not of Rhythm, but of Balance.