2. Triple, (the old perfect measure), in which there are three beats, the first one being accented, the second and third unaccented. Examples are 3/8, 3/4, 3/2, three-eighth, three-quarter, and three-half measure, respectively.
3. Quadruple, in which there are four beats, the first and third being accented (primary accent on one, secondary accent on three), the second and fourth unaccented. (See note above, under [Sec. 99].)
4. Sextuple, in which there are six beats, the first and fourth being accented, the others not. In rapid tempi this is always taken as compound duple measure, a dotted quarter note having a beat. It will be noted that the two measures
are identical in effect with
.
101. Other varieties of measure sometimes found are 9/8 and 12/8, but these are practically always taken as three-beat and four-beat measures respectively, being equivalent to these if each group of three tones is thought of as a triplet.
is identical in effect with