violent noise immediately behind them made every boy jump with surprise.
They wheeled about.
The door behind them had been blown shut. Biff Hooper, who was nearest, grasped the knob and tried to open it. He wrenched and tugged at the door, but it remained obstinate.
"We're locked in!" he muttered.
"We can get out, all right," said Frank. "There must be a door in this side hall."
He walked across the room and entered the hallway.
At the same instant a maniacal howl rang through the old house. The hollow echoes magnified its volume.
A flash of lightning illuminated the startled faces of the five boys. With one accord they rushed into the hallway. It was a narrow place, heavy with dust, and their feet thudded heavily on the mouldy flooring.
Crash!
At the far end of the hall they had a glimpse of falling plaster that fell in a great heap to the floor. A dense cloud of dust arose and filled the narrow chamber.
"Run for your lives!" yelled Frank.
But no sooner were the words out of his mouth than there came a ripping, crackling sound from overhead. Immediately above them, a large part of the ceiling, disturbed no
