On the night of May 11, 1812, John Williams of Redruth in Cornwall awakened his wife and told her he’d dreamed that he was in the lobby of the House of Commons and saw a man shoot the chancellor. Twice he went back to sleep, and twice he had the same dream.

Williams repeated the experience to friends in the following days, one of whom told him, “Your description is not at all that of the Chancellor, but is certainly very exactly that of Mr. Perceval, the chancellor of the exchequer.” Williams was explaining that he had never met or corresponded with this man when a messenger arrived from Truro with word that Perceval had been shot by an assassin in the lobby of the House of Commons on May 11 — the night of Williams’ dream.

According to a contemporary news account, Williams visited the spot six weeks later: “Immediately that he came to the steps at the entrance of the lobby, he said, ‘This place is as distinctly within my recollection, in my dream, as any room in my house,’ and he made the same observation when he entered the lobby. He then pointed out the exact spot where Bellingham stood when he fired, and which Mr. Perceval had reached when he was struck by the ball, where, and how he fell. The dress both of Mr. Perceval and Bellingham agreed with the description given by Mr. Williams, even to the most minute particular.”

In 1923, 7-year-old Rosemary Brown said she’d had a vision of a white-haired man in a black gown. “He told me that when I grow up, he would give me music,” she said.

Ten years later she recognized a picture of Franz Liszt. And in 1964, she said he returned, acting “like sort of a reception desk” to put her in touch with dead composers from Grieg to Chopin, who dictated new works to her from beyond the grave.

The classical music establishment gave these mixed marks. Leonard Bernstein and André Previn were skeptical, but Richard Rodney Bennett said, “If she is a fake, she is a brilliant one, and must have had years of training.” (She claimed to have had only three years of piano instruction.) “Some of the music is awful, but some is marvelous. I couldn’t have faked the Beethoven.”

Whatever the truth, the experiment is over now. Brown died in 2001, presumably joining her illustrious friends — and depriving them of an audience here below.

In his Lives (1827), Peter Walker recounts a baffling spectacle seen on Scotland’s River Clyde in the summer of 1686:

[T]here were showers of bonnets, hats, guns, and swords, which covered the trees and the ground; companies of men in arms marching in order upon the water-side; companies meeting companies, going all through other, and then all falling to the ground and disappearing: other companies immediately appeared, marching the same way.

Walker says these reports continued for at least three afternoons, but notes that fully a third of the assembled crowd, including himself, could see nothing. That sounds like a mass delusion, but “those who did see, told what works (i.e. locks) the guns had, and their lengths and wideness, and what handles the swords had … and the closing knots of the bonnets.” Make up your own mind.