Roger Mills wrote:
> Given a tritone, if you raise the top note 1/2 step and lower the
bottom tone 1/2 step, you resolve to a major chord; this is because, of
course, the tritone contains 2 of the 4 notes of a Dom7, which of course
resolves to Tonic.
And, of course, the chord of the diminished seventh, composed of two
interlocking tritones (e.g. C-Eb-F#-A), was a standard means of
modulation in the 18th-19thC for exactly that reason - drop any no