What was Ben Franklin's opinion on slavery?
It changed over time. When he was a young man he actually sold slaves in his store. Later he came to oppose and founded the first anti-slavery society in America.
Ben Franklins (with an S, no apostrophe) is a plural- two or more Ben Franklin. Ben Franklin's (s with an apostrophe) is possessive- something that belonged to one Ben Franklin. Ben Franklin's glasses. Ben Franklins' (s and then an apostrophe) is plural AND possessive. Something that belonged to more than one Ben Franklin.