Note 128 — {147} CHAPTER VIII {VI}

Rays of light, falling with any degree of obliquity upon the particles of that portion of watery vapour which lies near the surface of the earth, may be reflected, and pass off at an equal corresponding angle; so that if the eye be raised a few feet above the reflecting surface, an image of the corresponding arc of the sky is produced, as in the case of a sheet of water where the image, seen by the reflected light, is not that of the water, but the sky. Hence any object, which obstructs the rays of light in their passage from the parts of the atmosphere beyond the reflecting surface to that surface, is returned to the eye in a darkened image as from water.—James.