In telecommunication, a conservation of radiance is a basic principle of optics, that no passive optical system can increase the quantity L /n2, where L is the radiance[?] of a beam and n is the local refractive index.
Note:"Conservation of radiance" was formerly called "conservation of brightness" or the "brightness theorem."
... amassed a remarkable collection of the cars. Now known as the Schlumpf Collection[?], it has been turned into one of the world's great car museums, the Musée Nationale ...