The soul reveals itself in the voice only.... It is audible, not visible. [ Longfellow ]

In books lies the soul of the whole Past Time; the articulate audible voice of the Past, when the body and material substance of it has altogether vanished like a dream. [ Carlyle ]

The night is made for tenderness; so still that the low whisper, scarcely audible, is heard like music; and so deeply pure that the fond thought is chastened as it springs, and on the lip made holy. [ N. P. Willis ]

How absolute and omnipotent is the silence of night! And yet the stillness seems almost audible! From all the measureless depths of air around us comes a half-sound, a half-whisper, as if we could hear the crumbling and falling away of earth and all created things, in the great miracle of nature, decay and reproduction, ever beginning, never ending, - the gradual lapse and running of the sand in the great hour-glass of Time. [ Henry Wadsworth Longfellow ]