ACCENT AND REGNANT HARMONY 167 



it follows that the forms of music-rhythms are as diverse 

 as are the regular and irregular combinations of these 

 elementary group-numbers, first in the subrhy thm, next 

 in the potential subdivisions and expansions of all the 

 potential subrhythms, which is to say that the diver- 

 sity of music-rhythms is limitless. The classification 

 of music-rhythms is roughly outlined under the four 

 following heads: — 



I. Simple groups of 2. Simple groups of 3. 

 II. Compound groups of 2. Compound groups 

 of 3. 



III. Mixed groups of 2 and 3, as 5, 7, 10, 11, etc. 



IV. Simultaneous groups of 2 and 3, and of their 



compounds and mixtures. 

 The forms of I and II are regular; those of III 

 and IV irregular. It is possible, though rare, that the 

 subrhythmic periods and all the shorter and longer 

 periods resulting from the division and expansion of 

 the subrhythm may be regular throughout. But what 

 should be emphasized here is the fact that while a 

 subrhythm may be regular its shorter and longer 

 periods may present many irregular forms, and con- 

 versely, while the subrhythm may be irregular its 

 shorter and longer periods may present many regular 

 forms. This great variety of potential subrhythmic 

 forms, the limitless possibilities of their division and 

 expansion, the commingling and concurrence of regu- 

 lar and irregular forms, the infinite possibilities in 

 multi-voice music of the interplay of rhythms, not 

 only of one rhythm on another but of rhythms upon 

 rhythms, all this plainly intimates the inexhaustible 

 wealth of music-rhythm. 



