Bertram Boltwood

Bertram Borden Boltwood (July 27, 1870 Amherst, Massachusetts – August 15, 1927, Hancock Point, Maine) was an American pioneer of radiochemistry.

Bertram Borden Boltwood
Boltwood at Yale 1917
Born	July 27, 1870 Amherst, Massachusetts
Died	August 15, 1927 (1927-08-16) (aged 57) Hancock, Maine
Nationality	United States
Alma mater	Yale University
Known for	Radiochemistry
Scientific career
Fields	Radiochemistry
Influences	Ernest Rutherford
Influenced	Arthur Holmes

He graduated from Yale University, and taught there 1897-1900. He established that lead was the final decay product of uranium, noted that the lead-uranium ratio was greater in older rocks and, acting on a suggestion by Ernest Rutherford, was the first to measure the age of rocks by the decay of uranium to lead, in 1907. He got results of ages of 400 to 2200 million years, the first successful use of radioactive decay by Pb/U chemical dating (isotopes not discovered yet). More recently, older mineral deposits have been dated to about 4.4 billion years old, close to the best estimate of the age of earth.

Boltwoodite is named after him. He was a member of the Connecticut Academy of Arts and Sciences.

In his later days, Boltwood suffered from depression and committed suicide on August 15, 1927.