[5] Tillman spent fifteen months on the frontier at Fort Riley, Kansas, then returned to the academy for a period as assistant professor of mathematics.

[1] The following years would see Tillman alternating tours between teaching assignments at the academy and surveying the last unexplored portions of the American West.

[5] In late 1878, Tillman became the sixtieth of the founding members of Washington, D.C.'s Cosmos Club,[6] but resigned in 1881, after he was given permanent assignment at West Point as professor of chemistry, mineralogy, and geology.

[8] As full professor Tillman was given responsibility for redesigning the physical science curriculum at the academy; U.S. Army Adjutant General Richard C. Drum ordered Tillman and fellow academy instructor George L. Andrews to visit Harvard, Yale, and other American institutions of higher learning to investigate new educational technologies in order to incorporate them into the curriculum.

[12] Tillman authored several science textbooks for use by academy instructors, notably the physics work Elementary Lessons in Heat (1889),[13] Descriptive General Chemistry (1897),[14] and A text-book of Important Minerals and Rocks (1900).

[5] He spent some time in Italy, leaving at the outbreak of World War I;[5][24] Tillman settled in Princeton, New Jersey, continuing to write, presenting A Review of West Point's History before the New York Historical Society in October, 1915.

[25] When Colonel Tillman was recalled from retirement to serve as USMA superintendent in June, 1917,[5] the cadet class of 1917 had already graduated two months early and been assigned to wartime posts.

In 2008, Kent Biffle of the Dallas Morning News reported receiving newspaper clippings from a local lawyer and historian on the subject of UFO sightings in Stephenville, Texas.

McIlhany discovered such a craft had landed on his property, and reported two human operators, a pilot and an engineer, who gave their names as "S.E.