It was quite dark by now, and the Professor watched his retreating form until it was lost in the night. Then he bent down and picked up the object which he had thrown upon the ground, and which glimmered faintly upon the dark surface of the heather on which it had fallen. He knew what it was, without the trouble of striking a match. It was typical of him that he handled it by the edges, and wrapped it carefully in his handkerchief before he put it in his pocket. Then he started once more on his homeward journey, his mind full of this interview with the man who called himself the Black Sailor.