The History of Arithmetic is known to us from only one reference to it in the writing of Porphyry. This reference tell us that the first book dealt with the Pythagorean idea of number and its interrelations with music. I’m not a musician but it seems ridiculous to me. Can any one tell me how?
This may help.
Here’s a fixed link, Larry Mudd.
The linked site is a very basic starter explanation of how physics and math interact with music.
Some people spend their whole careers studying this kind of thing. As a musician, I am fascinated by the role mathematics plays in music. It’s a very interesting topic.
Try searching around the internet. There’s bound to be plenty to occupy you.
Thanks for fixing the link, JJ…
I’m having an awful lot of trouble using the URL tags for the last couple days-- vB seems to want to insert extra stuff. 
Pythagoris’s discoveries have a lot to do with harmonics. If you play two C’s on a musical instrument, one octave apart, the frequency of the notes will be exactly double. Pythagoris realized that if you take two strings of the same length and same tension, and stopped the vibration on one of them at the midpoint, the two strings produce noted an octave apart. Changing the lengths of strings temporarily is how string instruments make a wide variety of notes.
Other proportions yielded different differences in notes, which eventually led to the development of the major/minor scales we use today.
Since all this happened in the “west,” we came up with the 7-tone scale. How did the Easterners come up with the 5-tone scale? Did they also have a method?