=Eight Modes in Use=.—The Church Scales were numbered from one to
eight; the Authentic Scales were given the odd, and the Plagal Scales
the even numbers, thus:
1. Dorian 2. Hypo-Dorian
related scales.
3. Phrygian 4. Hypo-Phrygian
related scales.
5. Lydian 6. Hypo-Lydian
related scales.
7. Mixo-Lydian 8. Hypo-Mixo-Lydian
related scales.
A melody in an Authentic Scale had to end on its Keynote, but a melody
in a Plagal Scale ended on the Keynote of its _related_ Authentic
Scale. Observe that the Dorian and Hypo-Mixo-Lydian Scales are
identical; but while the former had to end on the Keynote, D, the
latter ended on G, which is the fourth of its scale, and Keynote of its
_related_ Authentic Scale.
Traces of these Authentic and Plagal Scales may be found in many old
folk-songs. Thus, the melody of the “Last Rose of Summer” begins on the
Keynote, rises in the course of the melody to the octave, but ends by
falling to the Keynote; it is therefore Authentic. On the other hand,
the melody of “Robin Adair” begins on the fourth _below_ the Keynote,
rises to its octave, but ends on the fourth _above_ its initial note
and is Plagal; thus:
[Music:
Range Range