This plate sets forth the essential duality of the musical system of vibrations. It is a remarkable fact that the numbers of the vibrations of the major mode are the numbers for the string proportions of the minor mode; and vice versa, the string proportions in the major are the numbers of the vibrations in the minor. We have, however, to see that we use the proper notes and numbers; we must know the secret of Nature. This secret rests in the duality of the notes, and begins from the two D's. The center of gravity of the musical system of vibrations is found in the comma space between the |two D's as they are found in the genesis of the two modes. In these |two D's the vibration number and string proportions are nearly identical. Starting from this point as the center of gravity in the [Scientific Basis and Build of Music, page 118]
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]
Ramsay
It is a remarkable fact that the numbers for the lengths of strings producing the major scale are the number of the vibration of the notes of the minor scale; for example, string-length as 26 2/3 will give the vibrations for [Scientific Basis and Build of Music, page 87]
See Also
length
string
Ramsay - PLATE IV - Oscillation and Vibration
String Theory
Laws of String Vibration
nine string chord
sympathetic string
harp string