AN UNPUBLISHED LECTURE BY HERTZ,HEINRICH - ON THE ENERGY-BALANCE OF THE EARTH

This paper presents a recently discovered and newly translated manuscr ipt of a lecture by Heinrich Rudolf Hertz, long famous for his 1888 di scovery of long-wavelength electromagnetic waves. Hertz delivered this address on 20 April 1885 as his inaugural lecture to the faculty at t he Technische Hochschule in Karlsruhe (now the Universitat Karlsruhe), where he was to make his most important contributions to physics. Alt hough written over 110 years ago, this historical document records bot h Hertz's insightful view of the Earth's energy situation at that time and his remarkably good order-of-magnitude estimates of the energy so urces then known to be available to the Earth. (C) 1997 American Assoc iation of Physics Teachers.