"" I wonder why they used the word “expedition “ in the article instead of conference.""
May be a check of word use in 1915 may be a start as to why use the word “expedition “ in the article instead of conference.
From a 1913 Websters Dictionary that is on line: (
https://www.websters1913.com/words/Expedition)
"Expedition
Ex`pe*di"tion (?), n. [L. expeditio: cf.F. expédition.] 1. The quality of being expedite; efficient promptness; haste; dispatch; speed; quickness; as to carry the mail with expedition.
With winged expedition
Swift as the lightning glance. ?
2. A sending forth or setting forth the execution of some object of consequence; progress.
Putting it straight in expedition. ?
3. An important enterprise, implying a change of place; especially, a warlike enterprise; a march or a voyage with martial intentions; an excursion by a body of persons for a valuable end; as, a military, naval, exploring, or scientific expedition; also, the body of persons making such excursion.
The expedition miserably failed.
Prescott.
Narrative of the exploring expedition to the Rocky Mountains.
J. C. Fremont.
It could be that in 1915 definition "3" is the reason. Was Ford etal looking for an answer to Peace? in a world that was beginning a very long war, where all sides would not be home by Christmas until after 1918?
((
Conference
Con"fer*ence (?), n. [F. conférence. See Confer.] 1. The act of comparing two or more things together; comparison. [Obs.]
Helps and furtherances which . . . the mutual conference of all men's collections and observations may afford.
Hocker.
2. The act of consulting together formally; serious conversation or discussion; interchange of views.
Nor with such free and friendly conference
As he hath used of old.
Shak.
3. A meeting for consultation, discussion, or an interchange of opinions.
4. A meeting of the two branches of a legislature, by their committees, to adjust between them.
5. (Methodist Church) A stated meeting of preachers and others, invested with authority to take cognizance of ecclesiastical matters.
6. A voluntary association of Congregational churches of a district; the district in which such churches are.
Conference meeting, a meeting for conference. Specifically, a meeting conducted (usually) by laymen, for conference and prayer. [U. S.] -- Conference room, a room for conference and prayer, and for the pastor's less formal addresses. [U. S.]))