group which the two alternating measures compose.  Thirdly, the quantitative values of these varying forms is related to their logical significance in the verse and the degree of accentuation which they receive.  Importance and emphasis increase the duration of the measure; the lack of either shortens it.  In this last factor, I believe, lies the explanation of the extreme brevity of dactyls appearing in three-rhythms.  When a specific rhythm type is departed from, for the purpose of giving emphasis to a logically or metrically important measure, the change is characteristically in the direction of syncopation.  Such forms, as has been said elsewhere, mark nodes of natural accentuation and emphasis.  Hence, the dactyl introduced into an iambic or trochaic verse, which, so far as concerns mere number of elements, tends to be extended, may, in virtue of its characteristic lack of accentuation and significance, be contracted below the value of the prevailing three-rhythm.  Conversely the trochee introduced into a dactylic sequence, in consequence of its natural accentuation or importance, may exceed in time-value the typical four-rhythm forms among which it appears.  The detailed examination of the relation of temporal variations to numerical predominance in the series, to subordinate structural organization, and to logical accentuation, in our common rhythms, is a matter of importance for the general investigation which remains still to be carried out.  In so far as the consideration of these factors entered into the experimental work of the present research, such quantitative time relations are given in the following table, the two types in all cases occurring in simple alternation: 

TABLE XXI.

  Rhythm. 1st Meas. 2d Meas.  Rhythm. 1st Meas. 2d Meas.

.     > >                          > >    .
q q q; q q %    1.000     1.091     q q %; q q q    1.000     1.140
.      >                            >      .
q q q; q q %    1.000     1.159     q q %; q q q    1.000     1.021
.    >                       >       .
q q q; q q %    1.000     1.025     q q %; q q q    1.000     1.267
>      .                              .        >
q q q; q q %    1.000     0.984     q q %; q q q    1.000     1.112
>  .                          .    >
q q q; q q %    1.000     0.766     q q %; q q q    1.000     1.119

As the disparity in numerical constitution increases, so will also the divergence in time-value of the two groups concerned.  When differentiation into major and minor phases is present, the duration of the former will be greater than that of the latter.  Hence, in consequence of the combination of these two factors—­e.g., in a syncopated measure of unusual emphasis—­the characteristic time-values may be inverted, and the briefer duration attach to that unit which comprises the greater number of elements.  Intensive values cannot take the place of temporal values in rhythm;