Charles Greeley Abbott was born in Wilton, NH on May 31, 1872 and was educated at The Massachusetts Institute of Technology (B.S. 1894, M.S. 1895). He served as assistant in the Smithsonian Institution Astrophysical Laboratory in Washington, D.C. (1895-1906), as acting director in 1906 and director from 1907-1944. From 1928-1944, he also served as Secretary of the Smithsonian Institution. Abbott devoted himself to a study of the sun's and the earth's radiation, successfully measuring the solar constant of radiation in 1903 and performed early research into the phenomena of sun spots. He founded observatories for the study of solar radiation at Mt. Wilson, CA, Mt. Harqua Hala, AZ., and Mt. Montezuma, Chile. Abbott invented a gyroscopic apparatus used as an inertial navigation instrument by the United States military forces in World War 1. He retired from the Smithsonian Institution in 1944. Abbot was the recipient of the Henry Draper Medal (1910) and the Rumford Prize (1915). He was elected Fellow of the American Academy of Arts and Sciences in 1921. He died in Washington, D.C. in 1973.