But it was just considered one of those many quirks of nature with no special meaning. Arnold Keyserling appears to be the first in modern times to realize the significance of this acoustic phenomenon. Harmonics pertain to reciprocal vibrations. Every time one tone, one vibration, is sounded, a series of discrete secondary sound vibrations are also created. This is an automatic phenomenon of nature, as natural and inevitable as gravity.
Vibrations never exist by themselves.
They always create secondary vibrations. These secondary vibrations are the harmonics. In music the secondary, reciprocal vibrations are called the undertones and the overtones. The undertones are lower in pitch with longer waves, and the overtones are higher in pitch with shorter waves. The overall string is vibrating at low C and this is the principal tone we hear.