The tuning fork, a two-pronged metal device used for tuning musical instruments, was invented in the 1700s by John Shore, a trumpeter who played with composer George Frederick Handel.
When struck, the U-shaped tuning fork vibrates at 440 cycles per second. It produces a tone which is always the same, regardless of temperature, moisture or other cond-tions theat can affect the pitch and tone of a musical instrument. Tuning forks are made for any note of the musical scale.