The average mean variations of the earlier intervals thus present changes which are analogous to and synchronous with those of the final pause.  Their values in proportion to the whole duration of the intervals are as follows[13]: 

   [13] In the second line of figures has been added the series of
   values of the average mean variation for all four intervals of
   the group.

TABLE LXXIII.

Stress.  Initial.        Secondary.       Tertiary.       Final. 
M.V.    6.98 per cent. 12.25 per cent. 6.57 per cent. 22.0 per cent. 
M.V.    6.87     "     11.56     "     6.15     "     20.45    "

Those rhythmical forms having their accentual stress initial, or on the initial elements of the subgroups, are marked by a sensitiveness almost twice as great as those in which the stress is final, or on the final elements of the subgroups.

Finally, if we take the whole series of intervals severally, we shall find that this rhythmical variation holds true of each element individually as it does of their average.  The whole series of values is given in the table annexed.

TABLE LXXIV.

  Stress. 
  Interval.  Initial.  Secondary.  Tertiary.  Final.

First,   9.57 per cent. 13.23 per cent. 9.00 per cent. 11.45 per cent. 
Second,  5.53     "     10.60     "     8.70     "      9.00     "
Third,   5.83     "     12.93     "     2.00     "     12.90     "
Fourth,  6.57     "      9.50     "     4.90     "      7.85     "

It is an obvious inference from these facts that the position of the accent in a rhythmical group is of very great significance in relation to the character of the rhythmical movement.  The initial accent gives incomparably greater cooerdination and perfection to the forms of uttered (produced) rhythm than does the final.  It is in this sense the natural position of the accent, because on the success and fluency of this cooerdination the aesthetic value of the rhythm depends.

In general, though not so unequivocally, the four-beat rhythms show a progressive increase of stability in passing from the simple interval to the group, and from the smaller group to the larger.  The series of values for the four accentual positions follows.

TABLE LXXV.

Stress.       Single Interval.   4-Beat Group.   2-Beat Group. 
Initial,      7.27 per cent.    8.20 per cent.  8.17 per cent. 
Secondary,   11.60     "        9.60    "       6.25     "
Tertiary,     3.20     "        3.40    "       2.25     "
Final,       10.22     "        6.30    "       6.00     "
Average,      8.07     "        6.87    "       5.67     "

Here, as in the preceding rhythmical forms, the most constant relation is that of smaller and larger groups, in which no exception occurs to the excess of mean