A

David

Darling

Boltwood, Bertram Borden (1870–1927)

Bertram Borden Boltwood

Bertram Boltwood was an American chemist and physician who did important research in radioactivity which led to the development of the theory of isotopes. Boltwood discovered (1907) ionium – a radioactive isotope of thorium. He was professor of radiochemistry at Yale University (1910–1927).