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Bertram B. Boltwood

Bertram Borden Boltwood was born on July 27, 1870, in Amherst, Massachusetts. His paternal ancesters had come from Great Britain two centuries earlier and were a prominent family in New England. His father, a lawyer, died when "Bolty" was two years old, and the boy, an only child, was raised by his mother in her home town of Castleton-on-Hudson, New York. His mother's family had come to America from Holland, also in the 17th century. Boltwood's mother was not wealthy, but she was affluent enough to send him to private school and, befitting her social position, destined him to attend Yale, his father's college. He entered Yale's Sheffield Scientific School in 1889 and upon completion of the three-year program took highest honors in chemistry. Next came two years of postgraduate work in Munich, where he specialized in analytical techniques. He graduated from the Sheffield Scientific School in 1892, then studied at Leizig and Yale where he received his PhD in 1897.

Boltwood joined the faculty at Yale and taught there for the rest of his life, 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 was the first person to use the U/Pb method of dating uranium-bearing minerals. He published these results in 1907, giving ages from 535 million years for a uraninite from a pegmatite at Branchville, Connecticut to 2200 million years for a thorianite from Ceylon (now Sri Lanka). This unambiguously showed that the age of the earth had to be at least 2 billion years, to the considerable relief of evolutionary biologists and most geologists. He died in 1927, at the age of 57. The uranium mineral boltwoodite was named in his honor in 1956.
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