Why are sounds heard better at night than in the day?
Because the air at night is condensed by cold, and becomes a better conductor of sound; also, because the nights are stiller, and fewer sounds take our attention.
Why is moist or damp air a better conductor of sound than dry air?
Because the particles of water in the damp air increase its power of conduction.
Why is sound heard farther when over the water?
Because the damp air over the water is a better conductor, and because it contains fewer objects to obstruct the waves of sound.
How far has the human voice been heard over the water?
The words “all’s well” have been heard across the Strait of Gibraltar, a distance of ten miles.
How far has the human voice been heard over the land?
It has been heard at the distance of four miles.