Ramsay
"The number 3 is the creative power in music, producing fifths, but it is under the control of the Octave prime - the number 2. It is the supreme octave which forms a boundary by making twelve fifths and seven octaves unite in one note. Within this horizon lies the musical system in its threefoldness - major (sharped), minor (flatted) and chromatic (accented)." [from, The Scientific Basis and Build of Music]