An analysis of the constituent intervals of the unit group, as shown in the second and third lines of the table, reveals the existence of a complex subordinate rhythm.  The two components of the rhythmical group do not increase and decrease concomitantly in temporal value in composing the alternate long and short measures of the fluent rhythm.  The movement involves a double compensating rhythmical change, in which the two elements are simultaneously in opposite phases to each other.  A measure which presents a major first interval contains always a minor second; one introduced by a minor first concludes with a major second.  The ratios of these two series of periodic variations must themselves manifestly be different.  Their values are, for the first interval of the measure, 1.000:1.214; and for the second interval, 1.000:0.764.  The greater rhythmical differentiation marks the second of the two intervals; on the variations of this second interval, therefore, depends the appearance of that larger rhythm which characterizes the series.  The ratios of these primary intervals are less consistently maintained than are those of the rhythmical measures built out of them.  It will be noted that in both intervals there is a tendency for the value of the difference between those of alternate groups to increase as the tapping progresses.  This change I have interpreted as indicative of a progressive definition in the process of rhythmization, depending on an increase in cooerdination and differentiation of the reactions as the series advances.

A simple stress on alternate elements was next introduced in the series, forming a simple trochaic measure repeated without interruption.  The quantitative results follow, arranged as in the preceding experiment.

TABLE XXXVI.

Quantity.  I II III IV V VI VII VIII IX X Measure, 1.000 1.035 1.070 1.035 1.087 1.070 1.071 1.052 1.070 1.070 1st Int., 1.000 1.000 1.111 1.000 1.055 1.111 1.166 1.111 1.111 1.111 2d Int., 1.000 1.025 1.051 1.051 1.102 1.051 1.025 1.025 1.051 1.051

Here again there is no progressive acceleration or retardation.  The rhythmical differentiation of alternate measures is very slight—­the average ratio of the first to the second being 1.000:0.993—­but is of the same type as in the preceding.  The excess in the amount of this differentiation presented by the first type of reaction over the second may be due to the presence of a tendency to impart rhythmical character to such a series of reactions, which, prohibited in one form—­the intensive accent—­finds expression through the substitution for this of a temporal form of differentiation.

In this trochaic rhythm the phases of variation in the constituent intervals of the measure are concomitant, and their indices of differentiation almost identical with each other.  Their values are, for the first, 1.000:0.979; and for the second, 1.000:0.995.  The higher index is that of the first interval, that, namely, which follows the accented beat of the measure, and indicates that the rhythmical change is due chiefly to a differentiation in the element which receives the stress.