Signals Between Aeroplanes and Artillery
This Royal Flying Corps instruction book and signal guide was produced on heavy card stock and provided quick reference for pilots and observers directing artillery fire by airplane. This guide belonged to Lt. John A. Sperry, a pilot with the 139th Aero Squadron. In August 1918, Sperry was reassigned to the 22nd Aero Squadron and became one of the unit's first flight commanders. On Aug. 21, 1918, Sperry, flying his SPAD XIII, made the squadron's first combat patrol in preparation of the approaching St. Mihiel offensive. (U.S. Air Force photo)