Radium and the Electron

Abstract

WHEN we view in perspective the extraordinarily rapid progress of physics during the last twenty-five years, we cannot fail to be impressed with the great significance to be attached to the discovery of X-rays by Röntgen in 1895, not only from its intrinsic interest and importance, but also from the marked stimulus it gave to investigations in several directions. In fact, this discovery marks the beginning of a new and fruitful epoch in physical science, in which discoveries of fundamental importance have followed one another in almost unbroken sequence.