These experiments have all pointed to the fact that our pleasure in repeated space forms is an immediate experience. We do not look over the series and merely recognize that regular repetitions occur, but there is an immediate _feeling_ of repetition, analogous to our feeling of auditory rhythm. This feeling does not always accompany a recognition that certain repetitions occur, but is a distinct experience in itself dependent upon certain conditions in the series. The series excites a certain response in the observer, which, if it corresponds with his rhythmic organization, is pleasant, and if not, is otherwise. With a certain class of subjects this rhythmic response is very noticeable, and they feel it as a conscious part of the experience. With others, the symmetrical properties of the series are the more prominent, and they detect no rhythmic response until the necessary objective conditions for such a rhythm are violated. Then they feel it as keenly as the other type. In a series of units, there is a rhythmic discharge of energy on each, the fixed temporal intervals being regulated by the alternating space. When the units are too near together, or when the alternating spaces vary irregularly in size, this rhythm is disturbed. If the alternating spaces vary regularly in size, a richer rhythm is introduced, which increases the pleasure up to a certain point when more variation makes it too complicated, and confusion results. When one element alternates with another, the one on which more energy is expended for any reason becomes the principal unit. The other has less significance as to its content than as to its size, for on this depends the regularity of the rhythm. Variations in the content of alternating figures must be cautious not to disturb, by the extra attention necessary to take them in, the rhythm of the whole. Variation in the principal unit may take place almost without limit, provided there is an equal amount of interest in each, thus making a rhythm of equal discharges. There must be an alternation of _two_, _i. e._ of discharge of attention and rest. However rich the rhythm is made by greater and lesser accents or groupings, the rhythm must fall eventually into a discharge of attention, and a rest-period. In the temporal type of subject, to whom the actual _motion_ across the series is a necessary factor of the pleasure, this discharge and rest-period of _attention_ is exactly inverse to the _motion_ across the alternate and rest upon the unit. That is, on the principal unit is the discharge of the attention, but the rest-period of the motion across; while the alternate unit supplies the field which is travelled over, but requires but little attention.