TWILIGHT

is the ‘ reflection ’ of sunlight from the higher levels of the atmosphere which are still lit by the sun after it has become invisible from ordinary levels. Even when the sun is in the zenith of a cloudle sky, ‘ one-fifth ’ of the light on any given area of the earth’s surface is reflected from other parts of the sky than that through which the beams UGANDA reach directly to that area. When the sun is just above the horizon, more titan two-thirds of the total light Is thus reflected and when the sun has sunk below the horizon, all; the light comes in this way. UHLAND, The duration of twilight, however, varies greatly from practically nothing at the Equator to continuous * light ’ in the land of the * Midnight Sun.’