I had never even heard of the difference between equal temperament vs. natural harmonics, and the fact that string and wind instrument players can bend the note to the more pleasing natural harmonics, where obviously a keyboard player can't. (probably one reason I've never noticed or heard of it.)
This is so interesting to me: For over 2000 YEARS!!!, musicians, philosophers and mathematicians tried to derive a 12-tone scale that would provide the natural intervals of the harmonic series. Unreal! (I thought it just happened!) :)
He says there are Indian scales of 22 & 53 tones per octave! The Arabs have a 3/4 interval. But no mention as to how they were derived.
All this to learn intervals better and be able to compose faster...even w/o an instrument, something I'm sadly deficient at.