Harkins, William Draper (1873-1951), a United States physical chemist. In 1915 he suggested the theory of thermonuclear fusion—that great amounts of energy are liberated by the fusion of four hydrogen atoms to form a helium atom. (The energy released by hydrogen bombs is the result of thermonuclear fusion.) Harkins also introduced the theory, soon universally accepted, that the light and heat of stars are the result of thermonuclear reactions.

Harkins was born in Titusville, Pennsylvania. He received his Ph.D. from Stanford University in 1907. After 1912 he taught at the University of Chicago. In 1931 he discovered a new isotope of oxygen, oxygen 17. During World War II Harkins directed research on synthetic rubber for the United States government.