Her black eyes travelled over the walls and ceiling and floor, as though in search of a clue to her father's fate. She evinced a disposition to linger there, but Dick pulled her back into the office. "Now, Gracie, how did you get into the house?" "I'll show you. Come downstairs." Taking the candle with them they descended to the lower part of the premises. There were three small rooms in the basement, in addition to the kitchen, all in a state of ruin. He was filled with wonder when Gracie informed him that there was a cellar underneath the kitchen, for neither he nor the officials who had searched the place knew anything of it. "Pull up the trap door, Dick. There it is, under that old chair." The wonder still upon him he removed the chair, and, kneeling, lifted the trap door, beneath which was a short fixed ladder. "I'll go first," said Gracie, "then you can give me the candle, and come after me." It was done as she directed, and he found himself in a dungeon-like room, about ten feet square, without window or door in it. "I got in through that wall, Dick." It was the wall that divided the two houses. Dick looked and saw no means of entrance. "Can't you see how, Dick?" "No. You are a spirit." "Can a spirit do things that we can't?" "It is what people believe," replied Dick, doubtfully. "And see things that we can't?" "So they say." "If I was a spirit I'd soon find out where poor father is. I ain't a spirit, Dick. Look here." Stepping to a part of the wall which bore traces of crumbling away, Gracie pushed a brick into the cellar of the adjoining house; she pushed another, and that fell; another, and that fell. A rat scampered past, and gave Dick a shock. Gracie laughed. Then she wedged her small body through, and stood apart from him, he being in one house, and she in another. "Wait a bit, Gracie," he cried excitedly. "Hold the candle." There were other loose bricks which yielded to his pressure, and in a few moments he had made a hole large enough for a man to creep through. Dick and Gracie were now side by side. "Easy, ain't it, Dick? We'd best put up the bricks, in case of accidents." "You ought to have been a detective," said Dick. "I shouldn't have made a bad one, I don't think," she answered, with unemotional complacency, proceeding to replace the bricks, which she did very carefully, even fixing the loose mortar about them. The work was done so neatly that nothing but the closest scrutiny would have led to the discovery of the unlawful communication between the houses. "Dick," said Gracie, "Mr. Samuel Boyd was as artful as they make 'em. Do you think he went in and out through this hole?" "He'd have been in a rare mess if he did," replied Dick, brushing the dust from his clothes. "The puzzle is what he wanted in an empty house. Supposing he did not wish to go back, how did he get out of it?" "This way."