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Marie Curie: Discovery of Radium, 1909

Polonium and Radium

Curie now expanded her search for other "Becquerel-ray emitting" compounds using pitchblende from Joachimstal, Austria, and found the element thorium to have the same emission characteristics as uranium. She coined the term "radioactivity" to describe this property. Her next hypothesis—that certain complex materials, such as pitchblende, achieved their high radioactivity from the presence of additional as yet unknown elements—must now be tested by isolating such elements.

Pierre Curie joined Marie in the next stage of the task where various chemical extraction techniques were used to separate the components of pitchblende. His electrometer was again used to measure radioactivity in the resulting fractions. From this work, in 1898, the Curies reported the existence of two new, separate elements that they named polonium and radium.

Suggestions
Text Suggestions (248K)
To Harry F. Keller from William J. Hammer, a consulting electrical engineer, November 10, 1908.
Referring to suggestions for minor text alterations to the report.

Recommendation report
Recommendation Report (157K)
To Alfred Rigling from Harry F. Keller, November 16, 1908.
Transmittal letter for the recommendation report, ready for signatures of subcommittee members.