"A Great Shaking."

It was still dark on the morning of 18 November 1755, when Harvard professor John Winthrop was jolted awake by the shaking motion of his house. He knew it was an earthquake: he had felt similar tremors in 1727, when he was thirteen, but these were more violent and longer-lasting. He kept to his bed while the house continued to shake around him, and objects fell from their places. When the shocks eventually subsided, Winthrop leapt from his bed and struck a light. His pendulum clock said the time was 4:11, but it had stopped, thrown off balance by the first shock. He then looked at his pocket watch, and it was nearly four minutes farther along. The earthquake had lasted about three and a half minutes, but it had been long enough and strong enough to do considerable damage: some...