The influence of the rate of succession on the rhythmical unit is not confined to its segregation from adjacent groups, but affects the internal configuration of the measure as well. With every acceleration in rate the relative preponderance of the interval following the accented element (in rhythms having initial stress) increases; as the rate is retarded, smaller and smaller degrees of difference in the values of accented and unaccented intervals are discriminated. In this regard the influence of reduction in the absolute value of the separating intervals is analogous to that of increased accentuation within the group. In fast tempos and with high degrees of emphasis the interval following the initial accent is relatively longer, that following the unaccented relatively shorter, than at slow tempos and with weak emphasis. This is but another way of expressing the fact that as the elements of the auditory series succeed one another more and more slowly the impression of rhythm fades out and that as their succession increases in rapidity the impression becomes more and more pronounced. The following table presents these relations in a quantitative form for trochaic rhythm. The figures represent the number of times the second, or group interval, was judged to be greater than, equal to, or less than the first or internal interval of the group. Three rates were compared together, having average intervals of 5/12, 3/12 and 2/12 sec. Six observers took part, but only a small number of judgments was made by each, to which fact is probably to be attributed the irregularities of form which appear in the various curves:

Ratio of 1st to 2d 5/12 3/12 2/12 Interval + = — + = — + = — 1.000: 1.057 95.0 0.0 5.0 100.0 0.0 0.0 100.0 0.0 0.0 1.000: 1.000 94.7 5.3 0.0 86.0 10.5 3.5 87.5 12.5 0.0 1.000: 0.895 40.0 60.0 0.0 46.2 49.6 3.3 74.1 18.5 7.4 1.000: 0.846 41.0 50.0 9.0 39.4 54.6 6.0 40.0 52.0 8.0 1.000: 0.800 20.0 60.0 20.0 13.0 70.0 17.0 53.8 46.2 0.0 1.000: 0.756 29.4 23.5 47.1 21.8 43.4 34.8 28.0 72.0 0.0

Av. for all ratios, 53.3 33.1 13.5 51.1 38.0 10.8 63.9 33.5 2.6

Within the limits of its appearance, as the figures just presented indicate, the force, definition and persistency of the rhythmical impression do not continue uniform. At the lowest rates at which rhythm appears the integration of the successive groups is weak and their segregation indistinct. As the rate increases the definition of the rhythmic form grows more precise, group is separated from group by greater apparent intervals, and the accentuation of the groups becomes more pronounced. In subjective rhythmization of an undifferentiated series, likewise, the impression of segregation and periodic accentuation