 After the battle , the 21st took up camp in the former Confederate fort , remaining there for nearly a month . During that time , Lt. Col. Maggi , determined to make the 21st as disciplined as a regiment of Regulars , enforced stern standards for drill and dress parades . After the near mutiny of one company , Maggi submitted his resignation . Maj. William S. Clark , a professor of chemistry at Amherst College , was promoted to lieutenant colonel and assumed command of the regiment on February 28 , 1862 . 
