"The thing is astonishing--remarkable," he said to Mrs. Morton, who was regarding him intently. "I confess that so far I am quite in the dark. I feel sure that whoever entered the room, or left the message, must have done so by means of the fire-escape, and yet, how was it possible, without marks having been left upon the paint? I think I shall make another and even more careful examination, in the hope that some slight clues may have escaped me." He once more made his way toward the girl's room, followed by Mrs. Morton. The room was precisely as they had left it. The window facing to the rear was wide open, Duvall having omitted to close it after his examination of the fire escape. The window fronting on the court was raised perhaps six inches. And yet, to the utter amazement of them both, there lay on the floor of the room, near its center, a square white envelope, addressed in typewriting to Ruth Morton. Duvall sprang forward and seized it with an exclamation of astonishment. It bore the same seal, in the same black wax, and upon it was the same semi-circular row of indentations. He tore the letter open. Its typewritten message was brief but significant. "Only twenty-seven days more," it read. The grinning death's head seal seemed to Duvall's astonished eyes even more terrifying than before. With a bound he reached the rear window, and swung himself upon the fire escape. There was no one in sight. The gray surface of the ironwork showed not the slightest scratch, save those made by his own heels earlier in the day. The steps of the ladder leading up to the next floor were glistening, immaculate. Those of the one to the floor below were equally so. He re-entered the room, and going to the opposite window, threw it wide open. The three dormer windows of the adjoining house were gray, dusty, as though they had not been opened for years. He turned to his companion with a look of amazement. "In all my experience, Mrs. Morton," he said, "I do not think that I have ever encountered anything quite so astonishing. That letter must have been placed there while I was in the apartment above. Your cook, your maid, are out. Certainly you did not place it there yourself. And yet we know that someone has been in this room, or at least delivered the letter, during the past fifteen minutes. Had I not found it here myself, I should have been almost tempted to disbelieve it, but I am forced to admit its truth." Mrs. Morton stood wringing her hands. "It--it seems almost supernatural," she exclaimed. "Poor Ruth. What are we to do?"