Ramsay
"The prime 5, like the prime 3, produces new notes. One of these, namely A5, is derived from unity, i.e., the note produced by the ratio of 1:2; the second note is produced from the note derived from the first power of 3, namely E15; and the third is produced from the note derived from the second power of 3, namely B45. The notes thus produced by the prime 5 are the middles, that is, the thirds of the chords. As it is the second and third powers of 3 which possess great centrifugal force, and not the first power of that number; and as it is only the first power of the number 5 which Nature employs in this business, so this makes the character of the notes produced by the prime 5 to depend on the character of the notes from which they are derived. One of the 3 notes produced by the prime 5 is derived from unity, that is the note produced by the ratio of 1:2, and like that note it is strongly acted on by the force of gravity.¹ A second note produced by the prime 5 is derived from the note produced by the second power of 3, and like that note it possesses increased" [Scientific Basis and Build of Music, page 27]