Curie recounts the research that led to the discovery and isolation of radium. Beginning with Henri Becquerel’s work on uranium rays, she explains how measurements of radioactivity showed that some uranium-bearing minerals were unexpectedly active. This suggested the presence of unknown radioactive elements and led Curie and Pierre Curie to undertake a lengthy process of chemical separation and measurement.

She describes the practical difficulties of the work, including poor laboratory conditions, limited resources and the very small proportion of radium in suitable ores. Curie then outlines radium’s intense radiation, its use in medical treatment and the growing understanding that radioactive atoms can spontaneously transform into other elements. She stresses that the original research was undertaken as pure science, without knowledge of its later applications. The address closes by presenting radioactivity as an active field of investigation and encouraging further scientific research.