Ramsay
If we view the Diatonic scale from the standpoint of their harmonizing, it is the first five notes of the octave which are the natural scale. The eight notes of the octave form a compound scale. So, in this view, in the octave of notes we have before us two scales; and this is true in both major and minor modes after their own dual fashion. In each of these two diatonic modes, the major and the minor, there are two semitones; but there are only two semitones altogether in the twofold system. When the major is generated by itself it has them both; and when the minor is generated by itself it also has both; but when the major and the minor are generated simultaneously, or as one great dual outgrowth, while the major in the ascending genesis is producing the semitone E-F, the third and fourth of its octave scale, the minor responsively in the descending genesis is producing the semitone B-C, the second and third of its octave scale. In this view of them, therefore, the semitone E-F belongs genetically to the major, and B-C to the minor; and this claim is asserted in the major tonic chord C E G, in which its own semitone is [Scientific Basis and Build of Music, page 64]

embedded; and in the minor tonic chord A C E in the same way is embedded its own semitone; and in these chords they appear in their proper places as third and fourth, C, d, E f, G; and second and third, A, b C, d, E. It is these first five notes of the octave scale which in a very distinctive way constitute the natural scale, which can be harmonized consecutively in one manner. The octave is seen in this view to be a compound scale, inasmuch as a compounding method of harmonizing has to be resorted to in passing consecutively from the sixth to the seventh. Similar compounding has to be done in the minor as well.¹ [Scientific Basis and Build of Music, page 65]