The two notes required for the scale of
E minor are the F# of G, and the D of C major;
for B minor, the C# of D, and the A of G major;
for F# minor, the G# of A, and the E of D major;
for C# minor, the D# of E, and the B of A major;
for G# minor, the A# of B, and the F# of E major;
for D# minor, the E# of F#, and the C# of B major.
In a similar and responsive way Duality provides for the six major scales with flats.
The two new notes required for the scale of
F major are the Bb of D, and the D of A minor;
for Bb major, the Eb of G, and the G of D minor;
for Eb major, the Ab of C, and the C of G minor;
for Ab major, the Db of F, and the F of C minor;
for Db major, the Gb of Bb, and the Bb of F minor;
for Gb major, the Cb of Eb, and the Eb of Bb minor.1
The scales march on following each other methodically, whether they be written with sharps or flats, and
"Not a step is out of tune, as the tides obey the moon."
The most natural, because the genetic, way to write the scales is to make the major scales all in sharps, after C, because the major genesis is upward in ratios ascending; and to make the minor scales all in flats, after A, because the minor genesis is downward in ratios descending. Let the young student, however, always keep in mind that the sharps and flats are simply marks to show how Nature, at whatever pitch we are taking the scales, is securely keeping them in the same form as when they are first generated; and in their birthplace no sharps or flats are needed.
It must be noted that the two new notes needed for each new scale are quite a different affair from the sexual note, that is the note which is different in major and minor, e.g., the two D's in major C and minor A. The
1 See Plate XII. - The mutual furnishings of Major and Minor.