Stevens pushed gently on the panel against which he had originally struck so hard a blow. To the amazement of the onlookers, the panel fell into the gable with a mighty crash.
"I thought so," he nodded. The others had leaped to the far side of the room. Mr. Presby came hobbling up, fearing that still another disaster had fallen upon the house.
"Please look here, Mr. Presby," called Bob. "Here is the secret. See that narrow panel? It is a little wider than a man's body. It is hinged at the bottom. Attached to it were ropes running over pulleys in wooden tunnels. At the ends of these ropes are heavy weights. So nicely balanced were the weights that the pressure of a few pounds from this side would throw the panel inward. Any person leaning against it on this side would be dumped into the other room so quickly that unless he understood the mechanism, he would not know what had occurred."
"Wonderful," breathed the owner.
"It was evidently intended to afford a quick get-away in case the occupants of the house found it necessary to leave hurriedly. You will find the remnants of an old mattress in the gable there. I presume that was originally so placed that the person going through would slide from the smooth panel to the mattress without the least danger of injury. The instant his body left the panel the weights would pull the panel into place with a great bang. When the weights struck their foundation—the floor—another crash would be heard. Were I an Indian, I think I would run if I heard all that crashing and smashing. However, I have cut the ropes. You will have no recurrence of to-day's accident. The trap was open and both the young women fell into it while groping about in the dark in there. Is Miss Mollie seriously hurt?"
"One wrist is sprained and she is somewhat bruised. I do not believe it will prove to be anything serious," answered Mr. Presby. "Bob, I thank you," he added, giving the young man's hand a hearty grip.
"May I go down there now?" piped Tommy.
"You may not, sir," returned his father sternly. "You will keep away from that place entirely. I shall have the opening nailed up to-morrow. By the way, Robert, what did you find at the bottom?" questioned the master eagerly.
"A caved-in passage. I also found this. I intended to give it to you in the presence of Miss Thurston. However, it belongs to you."
Mr. Presby turned the metal box over in his hand reflectively.