Charles Henry Davis established the American Ephemeris and Nautical Almanac and the Navy’s Bureau of Navigation, directed the U.S. Naval Observatory, and served as chairman of the 1874 Transit of Venus Commission. Davis joined the U.S. Navy in 1823, serving at sea for seventeen years and becoming a sailing master in 1829. In 1842 he joined the United States Coast Survey, leading hydrographic missions and studying harbors along the east coast of the U. S. It was during his service with the Coast Survey that he began publishing scientific papers, largely on tides and ocean currents. In 1849 he was placed in charge of the American Ephemeris and Nautical Almanac, which provided information on the location of stars and other astronomical objects in the sky at given times, information that was in that era necessary for ocean navigation. He remained at the Ephemeris and Almanac until 1853, when he was called back into naval service. During the U. S. Civil War, Davis was an active commander, serving as chief-of-staff for the naval assault at the Battle of Port Royal and seeing action on the Mississippi River. In 1863, he established the Navy’s Bureau of Navigation, where he remained for two years before taking charge of the U. S Naval Observatory.