February, helps found Society for Political Enquiries, dedicated to improvement of knowledge of government; elected first president. Named president of reorganized Pennsylvania Society for Promoting the Abolition of Slavery, April 23; devotes much of remaining time and energy to abolition. Serves May 28-September 17 as Pennsylvania delegate to Federal Constitutional Convention. Opposes salaries for highest executive positions. Argues June 11 that representation to Congress should be proportional to population. Moves June 28 that sessions of Convention be opened with prayer; motion, proving controversial, is dropped. July 3, proposes "Great Compromise" on representation, making representation proportional to population in House and equal by state in Senate; approved by Grand Committee, and enacted by Convention July 16. Argues August 7 and 10 for extending right to vote as widely as possible; condemns property qualification for franchise and for officeholding as unnecessary. James Wilson reads Franklin's closing speech at convention September 17, urging every member to "doubt a little of his infallibility," put aside specific reservations, and vote unanimously for approval of Constitution.