An excerpt from the INTRODUCTION. 1. Sound is the effect on the ear of a wavelike (undulatory) motion of an elastic medium, caused by the vibrations of an elastic body.
2. When the vibrations occur at regular intervals, and the waves are therefore of equal length, a
musical
sound is produced.
3. Musical sounds differ from each other (independently of their
duration
) in
intensity
,
character
and
pitch
, - determined respectively by the
extent
form
, and
frequency
of the vibrations.