 Something like a week into this trek, Wheeler realizes that he can perform an experiment. He selects a building with a high ceiling to sleep in, a library. Before turning in, he sets up a focalt pendulum. He suspends a heavy rock by wire from the ceiling, and sets it swinging. The following morning, the slow pendulum is still swinging, and it has precessed. It's swinging at about a right angle from the mark he had made before he went to sleep. That means the world is still spinning. On deflection, he doesn't know if they prove anything. It's not clear whether the sun or the moon still exist, or any celestial object other than the red-black eye socket at the horizon. The eye never moves. It casts long, threatening shadows, while being bright enough the blindwheeler whenever he has to walk in that approximate direction, which is about half the time. Regardless of the physical evidence, it doesn't feel as if he's walking on a real earth, or fully awake.