Music Theory
Lecture 4 on the Overtone Series

1. Silently press the E that is an octave higher and hold.  

2.  Strike the lower C. 

Hear how this overtone is getting fainter?

Now we have the first four overtones on this series, starting with the low C.
AT this point it is obvious that we have formed the C major Chord.  This overtone series is the nucleus of the music we hear today from hymns, blues, jazz or classical. 
This triad with its' tonic-dominant relationship, is the foundation of Western tonal music.  Remember, there is an overtone series starting on every tone, so this is only one out of HOW MANY?