It was the sound that made me open my eyes, like an insect buzzing but more digital. With one eye squinting in the brilliant September sunlight I turned my head to see an old man in his seventies sweeping a metal detector in a two foot swath of beach, left and right, left and right. He wore white ankle socks with sneakers and his head was covered with a beige brimmed cap. He did not raise his capped head, keeping it always focused on that two foot wide path waiting for a signal.