But let us proceed with our development, for we need another fifth, a lower one, a subdominant for our minor scale. Well, let us divide A5 by 3 and we have D1 2/3, the root of the lowest fifth; and if we divide A5 by 5 we have for our middle to this fifth F1, and this is F just as we find it at the major start, and identical in quantity in both major and minor. But let us examine the D1 2/3. It is not easy to compare D1 2/3 with D27 of the major; let us bring it up a few octaves by multiplying by 2. This will not alter its quantity, but simply give us the same quantity in a higher octave, in which we may more easily compare it with the major D1 2/3 multiplied by 2 is 3 1/3; multiplied again by 2 is 6 2/3; once more by 2 it is 13 1/3; and once more by 2 it is 26 2/3. Now we can compare it with D27 of the major, and we find this strange fact, that it is a little lower than the major D. The two D's are at the center of the dual system, but the center of the system is neither in the one D nor in the other, but as an invisible point between them, like the center of gravity in a double star; for the minor D is pushed a little below the center, and the major D is pushed a little above the center of the two modes of the system. [Scientific Basis and Build of Music, page 32]
Having found the framework of the major scale by multiplying F1 three times by 3, find the framework of the minor by dividing three times by 3. But what shall we divide? Well, F1 is the unbegotten of the 25 notes of the great genetic scale; B45 is the last-born of the same scale. We multiply upward from F1 for the major; divide downward from B45 for the minor. Again, B45 is the middle of the top chord of the major system, a minor third below D, the top of that chord, and the top of the whole major chord-scale, so B is the relative minor to it. Now since the minor is to be seen as the INVERSE of the major, the whole process must be inverse. Divide instead of multiply! Divide from the top chord instead of multiply from the bottom chord. Divide from the top of the minor dominant instead of multiply from the root of the major subdominant. This will give the framework of the minor system, B45/3 = E15/3 = A5/3 = D1 2/3. But as 1 2/3 is not easily compared with D27 of the major, take a higher octave of B and divide from it. Two times B45 is B90, and two times B90 is B180, and two times B180 is B360, the number of the degrees of a circle, and two times B360 is B720; all these are simply octaves of B, and do not in the least alter the character of that note; now B720/3 is = E240/3 = A80/3 = D26 2/3. And now comparing D27 found from F1, and D26 2/3 found from B720, we see that while E240 is the same both ways, and also A80, yet D26 2/3 is a comma lower than D27. This is the note which is the center of the dual system, and it is itself a dual note befittingly. [Scientific Basis and Build of Music, page 81]
So the dual system of Music revolves round a mathematical point which is in none of its notes, but in the empty space between the two D's. Like the earth, it is hung upon nothing. This is an exceedingly interesting musical phenomenon. In that comma of vacant space is music's center of gravity.
dual system, as the strings are shortened the vibrations of course are more, and as the strings are lengthened the vibrations are fewer. This is household lore now; but the new insight and the deeply interesting order of Nature is that the major and the minor contain each other and respond to each other in this striking way; and while manifesting such diversity of character are so essentially one. [Scientific Basis and Build of Music,page 119]
Another remarkable thing is that these dual numbers, when multiplied into each other, always come to 720. Now this number, as we see in the great genesis, corresponds to 1 in the major, being the point of departure for the development of the feminine mode, as 1 is the point of departure in the masculine mode. This 720 is the octave of 360, which is the number of the degrees of the circle, so divided in the hidden depths of human antiquity; and when F1 becomes F2, then B360 is the answering note and number in the dual system. All the notes in the masculine development are above F2; and all the notes in the feminine development are below B360. The unoccupied octave between F1 and F2 and that between B720 and B360 may be counted as the octave heads or roots of the two modes, and then F2 and B360 as the points from which the development of music's diversity begins; and it is noteworthy that the number of the degrees of the circle should be found in this connection. When was the circle so divided? Who divided it so? And why did he, the unknown, so divide it? Was Music's mystery known in that far-off day before the confusion of man's sinking history had blotted out so much of the pure knowledge of pristine days? [Scientific Basis and Build of Music, page 119]