He served in the Mexican–American War without seeing combat, attempted to keep the peace between Seminoles and settlers in south Florida, and taught artillery tactics at West Point, where he wrote The Artillerist's Manual in 1859.
Han gjorde tjeneste i den Mexicansk-amerikanske krig uden at komme i kamp, forsøgte at holde fred mellem Seminoler og nybyggere i det sydlige Florida og underviste i artilleritaktik på West Point, hvor han skrev The Artillerist's Manual i 1859.