ch between two tones sounding
at the same time.

A Melodic interval is the difference in pitch between two tones sounded in
succession by the same voice. [Fig. 1.]

[Illustration: Fig. 1.]

Harmonic intervals are divided into Consonances and Dissonances.

Consonances are classed as perfect or imperfect.

The Perfect consonances are the Unison, Fifth, and Octave. [Fig. 2_a_.]

The Imperfect consonances are the Major and Minor Thirds and Sixths. [Fig.
2_b_.]

All other intervals are dissonances.

[Illustration: Fig. 2.]

A Diatonic progression is one in which both name and pitch are changed.
[Fig. 3_a_.]

A Chromatic progression is one in which the pitch is changed a semitone,
while the name remains the same. [Fig. 3_b_.]

[Illustration: Fig. 3.]

Progression from one chord to another is called Harmonic progression; from
one tone to another, Melodic progression.

In melodic progression all major, minor, perfect and diminished intervals
are allowed except the major and minor seventh. The minor seventh may,
however, be used when harmony does not change (_a_). [Fig. 4.]

[Illustration: Fig. 4.]

In counterpoint there are Five Species, or orders. When the counterpoint
has one note for each note of the cantus firmus, it is of the First Species
(_a_); if it has two notes for each note of the cantus firmus, it is the
Second Species (_b_); if four notes, the Third Species (_c_); if two notes
syncopated, the Fourth Species (_d_); and a mixture of these species is the
Fifth Species, or Florid Counterpoint (_e_). [Fig. 5.]

[Illustration: Fig. 5.]

SIMPLE COUNTERPOINT IN TWO PARTS

FIRST SPECIES

Two-part counterpoint comprises a cantus firmus and a counterpoint. [Fig.
6.]

[Illustration: Fig. 6.]

Although in two-part counterpoint we have to deal with intervals, rather
than harmonies, still the harmonic progressions represented by these
intervals should be regarded.

The exercises should begin and close with tonic harmony. At the beginning
the unison, fifth or octave, and at the close the unison or octave, are
permitted. [Fig. 7.]

[Illustration: Fig. 7.]

After the first measure it is better to use imperfect consonances only. The
perfect consonances, however, may be used sparingly when a more melodious
counterpoint is thereby obtained.

The unison may be used in the first and last measures only. [Fig. 7.]

All progressions must be diatonic, and parts should not cross.

The repetition of