"Good-bye, Gottfried!" Daniel shouted, and then stood and watched for some time as the boat became indistinct, and quite lost itself, in the welter of shipping in the Pool of London, there below the charred battlements of the Tower. It was almost a mirror image of the way Leibniz had appeared, out of nowhere, forty-one years earlier, except that the mirror was a misty and a streaky one. For much had changed in those years and Daniel could not watch with the clear eyes of a young man.