Ramsay
"When Nature, who weighs the mountains in scales and the hills in a balance, and number and names the stars, takes hold of this vibration-material, she subjects it to the most rigorous measurement in marshalling that series of notes which constitute The Musical System. She is in no hurry in giving us all her gifts in this matter. She first of all gives us the interval of an Octave at one stroke, and in generating the seven notes which compose the three chords of the Diatonic Scale she carries the process up through six octaves..." [Scientific Basis and Build of Music, page 19]
being also the center of the diatonic triplet, B, D, F, which is the diatonic germ of the chromatic system. Four minor thirds upward or downward from C# we have a second chromatic chord, its central note being G. The dual1 of C# is E?; and there is the same order of keys on the keyboard2 below C# as there is above E?. Four minor thirds from E? upward or downward forms a third chromatic chord, the central note of which is A. The dual A, the center of the third chromatic, is G, the center of the second; and these two notes, by their duality, and by the duality of the two chords throughout, balance each other exactly on the keyboard on either side of the first chromatic chord, which contains all its own duals, and by this self-duality sits in the center, like the tonic chord among the diatonic three. [Scientific Basis and Build of Music, page 57]
See Also
Diatonic
Dominant
Dominant Chord
Ramsay - The Chromatic System, like the Diatonic, Threefold
Subdominant
Subdominant Chord
Tonic
Tonic Chord