But while he was still gazing through the pane, the sound of a distant train on the railroad came through the night. The watcher was scarcely aware of it until he saw Piper start up in his chair, listening, with a roused, intent expression. The girl ceased from her reading; Scofield stopped his work and looked at their guest. No one spoke in the little room. The noise of the train grew louder; now it became a rumbling hum or a rattle--busy, swift, determined in character. It was as if a gigantic shuttle were being driven through the woof of the darkness, to carry one more strand into that great web of civilization, woven day and night continually. But there was something mysterious and warning in the sound besides. Under the general subdued roar could be heard the sharp click of the wheels from rail to rail, in definite pulsations; the sound thus grew so precise one might have suspected that it would break into speech. Had it not some message to deliver of which this was the vague prelude? That at least was what Piper seemed to hope as he rose excited, finally gaining his feet, with a quicker intelligence in his face than had been there before. As if it would be possible to catch the message more distinctly should he look out, he turned his eyes toward the window. Hounshell barely missed betraying himself there, but slid away into the dark swiftly. "Was that a face?" Simeon Piper demanded. "No; I see it must have been an illusion," he added, despondently, once more putting his hand to his head. The father and daughter exchanged looks of pity. By this time the cars had got farther off and were less audible. Piper's agitation died away proportionately, and he sank back into his seat. But the same sort of thing happened on the following day when he heard the distant movement of a train. "Listen!" he cried to Addie, who was with him. "Don't you hear? It's going to say something. I shall get hold of the idea and find out what is the matter. Listen! listen!" Then, as before, the hollow rumble diminished, gradually softened to a stir no louder than a sigh, and finally was quite lost. Only the baffled breeze continued its hopeless search among the leafy boughs by the river. "What is it you think you might hear?" asked Addie, gently. The strong man looked at her with tears in his eyes. "A secret, young lady; a secret! I knew it, and now it is gone. It's strange that cars should excite me this way, but something has hurt my brain. You are very kind; and if you go on being so perhaps my mind will get right again." A week passed. Piper listened each day to the passing trains; sometimes at night too, when he lay alone, and it seemed still more likely that through its relation with this sound the lost clew might disclose itself. But all in vain; he was unable to recover what had escaped him.