The case is no different with regard to sound. When we speak of a sound
coming from a bell, what we really mean is that the vibrations of the
bell have set up waves in the air between it and our ear, which have
produced corresponding vibrations in the ear; that a nerve current was
thereby produced; and that a sound was heard. But the sound (i.e.,
sensation) is a mental thing, and exists only in our own consciousness.
What passed between the sounding object and ourselves was waves in the
intervening air, ready to be translated through the machinery of nerves
and brain into the beautiful tones and melodies and harmonies of the
mind. And so with all other sensations.
