 The next thirty years of Tillman's life were devoted to writing and teaching at the academy. He wrote for popular periodicals like Popular Science and Cosmopolitan and literary journals like American Monthly Review of Reviews. Tillman authored several science textbooks for use by academy instructors, notably the physics work Elementary Lessons in Heat (1889), Descriptive General Chemistry (1897), and A text-book of Important Minerals and Rocks (1900). He was responsible for the academy's mineralogical and geological cabinet. Tillman also wrote a series of memoirs which have been featured in the works of Miami University historian Dwight L. Smith.
