64. In thus qualifying the tones, the student is influenced largely by
the rhythmic location of the tones ; the one which occupies the accented
fraction of the beat is somewhat more likely to be essential, while the un-
accented fractions are apt to be filled in with unessential tones. For
illustration (the unessential tones marked x) :



x x x x x



I



Ex.
54.
2z



r



The d and b in the first measure are so-called Passing Notes.
As may be seen, this counterpoint would be quite perfect if the unes-
sential tones (marked x) were all omitted, — thus :



m



i



j-j



i



Ex.
55.
1—r



Tj



T^T



from which the conclusion is drawn, that these tones are unimportant,
unessential.
Invert these examples ; that is, copy them out, placing the upper part
an octave lower, and the lower part an octave higher, than here written.
65. But this is not the only test. The most reliable guide is, after
all, the harmonic quality of the tone. A tone which is foreign to the chord
of the beat cannot be essential ; it must be unessential, even when it oc-
cupies the accented fraction of its beat. This is seen in Ex. 54; all the
tones marked unessential are foreign to the harmony (chord) of the beat,
excepting the d in the second measure, and the d at the end of the third
measure. (These two <f s are considered unessential, because they are
less accented than the harmonic tones which precede them.)

In the following version, with three notes to each one of the given
part, some of the unessential tones, foreign to the chord of the beat, ap-
pear on the accented fraction :



Par. 66.
RHYTHMIC DIVERSITY.
