December 18, 1925
There isn't anything very definite that I can say about the Sesquicentennial Exposition at Philadelphia. I suppose I am booked for exhibition and that will probably be on the 4th of July.
Source: "The Talkative President: The Off-the-Record Press Conferences of Calvin Coolidge". eds. Howard H. Quint & Robert H. Ferrell. The University Massachusetts Press. 1964.
Calvin Coolidge, Excerpts of the President's News Conference Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/349129