Secretary Charles G. Abbot Playing Tennis, by Unknown, Smithsonian Archives - History Div, Astrophysicist Charles Greeley Abbot, (Fifth Secretary of the Smithsonian, 1928-1944), playing tennis behind the Smithsonian Institution Building, the "Castle," next to the Smithsonian Astrophysical Observatory, in the South Yard. Abbot is seen here getting ready to serve the ball..