When the ground or water is warmer than the air, mists and fogs are
frequently formed; and since water and marshy surfaces cool less rapidly
than dry land, mists and fogs are of more common occurrence in low, damp
situations than in dry, elevated districts. They are formed by the
condensation of the vapor, or, in other terms, its transformation into
the minute globules of water, which instead of descending to the earth
in the form of dew, remain suspended above the land or the water.