1775165438+1October 18, an earthquake occurred in Boston, Massachusetts. John winthrop, a professor at Harvard University, felt the earthquake and woke up. "I got up at once," he wrote. "Then I lit the candle. I looked at my watch and found it was 4 o'clock. 15 (morning). John, winthrop immediately rushed downstairs to look at his grandfather's clock. This clock stopped three minutes ago, which is 4: 12. The earthquake not only stopped the clock, but also shook the mantelpiece to the ground!