Bertram Borden Boltwood

Bertram Borden Boltwood 1870-1927, American chemist and physicist, b. Amherst, Mass., grad. Sheffield Scientific School, Yale, 1892. After graduate study at Leipzig and Yale (Ph.D., 1897), he taught at Yale until his death, serving from 1910 to 1927 as professor of radiochemistry. An expert in laboratory technique and apparatus, he gave much of his energy to planning and supervising the building of the Sloane Physics Laboratory and the Sterling Chemistry Laboratory, both at Yale. He did important research on radioactive elements (he discovered ionium, an isotope of thorium, but believed it to be a new element) and pioneered in the radioactive dating of geological strata.

Boltwood, Bertram Borden (1870–1927) Professor of radiochemistry at Yale University, in 1907 Boltwood made early determinations of the age of the Earth using uranium: lead ratios. He was able to show a long geologic time-scale of up to 2000 Ma. See RADIOMETRIC DATING.