John Drinkwater Bethune, A History of the Late Siege of Gibraltar 
John Hinkley operated a sawmill in Georgetown, Maine, during the mid-18th century. He joined the Continental Army during the Revolution, and served as a captain with the Massachusetts Militia until his death in an engagement at Castine, Maine, in 1779. Hinkley had three sons: Miller, David, and Ezekiel.
Samuel P. Hinkley, also a native of Georgetown, Maine, studied the art of nautical navigation in the 1830s. His studies included several different methods of sailing and the mathematical equations necessary to determine a ship's location and course.