They do not concern the analytical student intimately, but at least the general distinction between regular and irregular rhythm should be understood:--We have seen that the natural accent (the "heavy" pulse) is invariably represented by the first beat of a rhythmic group; and that one or two lighter pulses intervene before the next accent appears.

Further, it is self-evident that the rhythmic weight of a tone is proportionate to its length, or time-value; longer tones produce heavier, and shorter tones lighter, impressions.

The deduction from these two facts is, then, that the rhythmic arrangement is _regular_ when the comparatively longer tones occupy the accented beats, or the accented fractions of the beats; and _irregular_ when shorter tones occupy the accents, or when longer tones are shifted to any comparatively lighter pulse of the measure or group.
The rhythm of the second measure in Ex.

3 is regular, because the longest tone stands at the beginning of the measure, thus confirming (and, in fact, creating) the accent.

The rhythm in Ex.