Via Global Museum:
Museum finds "secret" message in Lincoln's watch
This is interesting. A watchmaker, 40 years after Lincoln's death, claims that he was fixing the President's watch on the day he learned that Fort Sumter had been attacked by the new Confederate States of America and that he had secretly inscribed the date and a message inside the watch, but never told anyone and that probably no one had ever seen this inscription since then.
Probably not. There are all sorts of funky reminiscences and legends that arise around famous people and stories that make their first appearance decades after the fact should be viewed with great suspicion.
But the guy's great-great grandson tells the story to someone at the National Museum of American History, which owns the watch, and they say, Sure, why not open it and take a look? And sure enough:
The engraving, by watchmaker Jonathan Dillon, is dated April 13, 1861, and reads in part: "Fort Sumpter was attacked by the rebels" and "thank God we have a government."