Arlene died a few hours after I got there. A nurse came in to fill out the death certificate, and went out again. I spent a little more time with my wife. Then I looked at the clock I had given her seven years before, when she had first become sick with tuberculosis. It was something which in those days was very nice: a digital clock whose numbers would change by turning around mechanically. The clock was very delicate and often stopped for one reason or another - I had to repair it from time to time - but I kept it going for all those years. Now, it had stopped once more - at 9:22, the time on the death certificate!

I remembered the time I was in my fraternity house at MIT when the idea came into my head completely out of the blue that my grandmother was dead. Right after that there was a telephone call, just like that. It was for Pete Bernays - my grandmother wasn't dead. So I remembered that, in case somebody told me a story that ended the other way. I figured that such things can sometimes happen by luck - after all, my grandmother was very old - although people might think they happened by some sort of supernatural phenomenon.

Arlene had kept this clock by her bedside all the time she was sick, and now it stopped the moment she died. I can understand how a person who half believes in the possibility of such things, and who hasn't got a doubting mind - especially in a circumstance like that - doesn't immediately try to figure out what happened, but instead explains that no one touched the clock, and there was no possibility of explanation by normal phenomena. The clock simply stopped. It would become a dramatic example of these fantastic phenomena.

I saw that the light in the room was low, and then I remembered that the nurse had picked up the clock and turned it toward the light to see the face better. That could easily have stopped it.

Surely You're Joking, Mr. Feynman!, "Los Alamos from Below" (third chapter of Part 3)

Alternate explanation: The clock stopped before his wife died, but the nurse recorded 9:21 as his wife's time of death, because she determined the time by checking the clock, not realizing it had already stopped.