From the Super Mario Wiki
The Spectacles are an item in the SNES and PC versions of Mario's Time Machine. It is a pair of thin-rimmed glasses that belongs to Benjamin Franklin. It is given to Mario by a stable worker while the latter talks about Thomas Jefferson and his views. After he mentions the other members of the Committee of Five, which includes Benjamin Franklin, he suddenly remembers that Benjamin left his glasses at the stable, and he asks Mario to return them. When talking to Benjamin, he also mentions that he cannot go to Independence Hall without his glasses (while also bragging about having invented bifocals). Once Mario gives him his Spectacles, he thanks Mario and goes on to talk about Thomas Jefferson's accomplishments.