Reviews two books about physicist Joseph Henry. `The Papers of Joseph Henry. January 1847--December 1849: The Smithsonian Years,' Volume 7, by Joseph Henry, edited by Marc Rothenberg, Paul H. Theerman and Kathleen W. Dorman; `The Papers of Joseph Henry. January 1850--December 1853: The Smithsonian Years,' Volume 8, by Joseph Henry, edited by Marc Rothenberg, Kathleen W. Dorman, Deborah Y. Jeffries and Frank R. Millikan.