August 29, 1901
In accordance with provisions of Section 179 Revised Statutes as amended by act approved August 5th, 1882 (22 Stats. at large 238), Brigadier-General G. S. Gillespie, Corps of Engineers, United States Army, is authorized and directed to perform the duties of Secretary of War during the temporary absence from the seat of Government of the Secretary of War and the Assistant Secretary of War.
WILLIAM MCKINLEY
William McKinley, Executive Order Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/205682