SON XV

THIRD SPECIES IN TWO OR MORE PARTS

[Illustration: Fig. 110.]

Previous suggestions when two or more parts have other than first species,
apply here.

In using the ninth of a chord it is well to keep it at least a seventh
distant from the third, as well as a ninth above the root, except in the
case of the dominant ninth in minor keys, where it may be separated by only
an augmented second ([b]). [Fig. 111.]

[Illustration: Fig. 111.]

In writing the third species in all parts, notes appearing simultaneously
should be harmonically related. Treat all tones foreign to the chord on the
first quarter as dissonances.

The cadences in Fig. 112 are good.

[Illustration: Fig. 112.]

EXERCISES

To cantus firmus _a_ write third species in one part, as previously
directed.

To cantus firmus _b_ write third species in two parts, as in Fig. 110_b_.
Write twice, changing the cantus firmus about.

Write one eight-measure phrase, mixing first and third species as in Fig.
110_a_.

CANTI FIRMI

[Illustration: Fig. 113.]

LESSON XVI

THIRD SPECIES (Continued)

EXERCISES

To the cantus firmus write third species in one part, as previously
directed.

Write one eight-measure phrase, mixing first and third species; also one
mixing first, second and third. [Fig. 114.]

Write one eight-measure phrase, using third species in all parts. [Fig.
110_c_.]

[Illustration: Fig. 114.]

CANTUS FIRMUS

[Illustration: Fig. 115.]

LESSON XVII

FOURTH SPECIES

[Illustration: Fig. 116.]

When the syncopation is a suspension or retardation, it is treated the same
as in harmony.

The retardation should always be prepared by the leading-tone.

When the syncopated note belongs to the harmony of the measure, it may be
left by a skip or stepwise progression. [Fig. 117.]

[Illustration: Fig. 117.]

The third may be omitted on the strong beat in this species, provided the
part having fourth species skips to the missing third, as at Fig. 117_a_.

Consecutive fifths, but not octaves, are saved by the suspension. Whenever
they occur, do not use the note of resolution as preparation of a
suspension, or tie it into the next measure (_a_), since it is really the
passing seventh, and that does not lend itself well to either of the above,
except in sequence as at _b_. [Fig. 118.]

[Illustration: Fig. 118.]

The seventh or ninth of a chord, except the major seventh, may be used as
preparation of