Which U.S. President gave Marie Curie a gram of radium in 1921?

U.S. President Warren G. Harding presented Marie Curie with a gram of radium in 1921.

The gift followed Curie’s first visit to the United States, organized to raise money for radium research. American journalist Marie Mattingly Meloney led a fundraising campaign called the Marie Curie Radium Fund. At the time, radium was extraordinarily expensive, and Curie’s laboratory in Paris lacked enough of it for continuing medical and scientific work.

Harding received Curie at the White House and presented her with a ceremonial key to a container holding one gram of radium. The material had been purchased with money raised by American women, who wanted to support the scientist’s research and honor her achievements.

Curie had already won the 1903 Nobel Prize in Physics and the 1911 Nobel Prize in Chemistry. The episode is sometimes confused with her wartime medical work: during World War I she used mobile X-ray units, but the 1921 American gift was radium, not an X-ray machine. The radium was intended for research rather than personal use.