"It would be worth big money to know just what is being said in there," returned Rouse regretfully.

"Of course, and that's what I am bound to find out."

"How do you propose to do it?" asked Rouse, in surprise.

"There is a room overhead."

"Undoubtedly."

"And in that room is a ventilating flue, which runs down through the room below and out through the roof above."

"I see! I see!" exclaimed Rouse, in high glee. "We have only to reach the ventilator to hear all that is going on in Bissell's room."

"Right, provided the ventilator in twenty-four is not closed."

"I've no fear of that—they're never closed."

"Very good; then we are likely to hear something to our advantage."