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."
... und die Bearbeitung derselben durch Vera (1868)
Erläuterungen zu Hegels Encyklopädie der philosophischen Wissenschaften (1871).
Two other of his works on ...