Lenard's Share in the Discovery of X Rays

Abstract

The Rumford Medal of the Royal Society had been awarded in 1896 to Philipp Lenard and Wilhelm Conrad Rontgen. Never before have two men shared this golden medal, which originated in a gift from Count Rumford in 1796 for the most important discovery in heat or light made during the preceding two years. The Royal Society wanted to testify its appreciation of their work in a common field, and it seems to be fitting at the fiftieth anniversary of the discovery of X rays to remember the man whose work is less well known. Lenard started his experiments with cathode rays influenced by the lecture of William Crookes (1879) before the Royal Society on April 3, 1879, on “Contributions to Molecular Physics in High Vacua”. Whereas Hittdorf and Crookes called attention to the events in the inner dark space surrounding the cathode, Lenard “glazed” the vacuum tube with an aluminium window and carried by this means the cathode rays outside the tube. H. Hertz (1892) discovered that flakes of metal are transparent to catho...