The title, "Tempus Fugit", translates to "time flies".
When Benjamin Franklin is asking Abbie which of his inventions are still around in her time he asks about his Franklin Stove. Actually the stove designed by Benjamin Franklin has a baffle in the back which required a fire burn continuously to create a draft as the smoke was initially drawn down before exiting up through the chimney. A man named David Rittenhouse much improved Franklin's design by switching the chimney from the bottom of the stove to the top, and as a result his stove was much more popular than Franklin's which reportedly sold quite poorly.
Abby tells Ichabod that the livery stable is going to be a Starbucks. In the pilot episode Ichabod tells Abby that the Starbucks used to be a livery stable.