"Perhaps. They know that James Monday will make it warm for them.
That letter put them on their guard."
"What a fool I was to deliver it, Dick! I ought to be kicked for doing it. If we had only opened it and read it!"
"The others must still be on the watch."
"Yes, unless they, too, have been captured."
The boys returned to the hole in the wall and, to occupy themselves, dug away at it harder than ever. Another stone was loosened and pulled into the cell.
"We're making a little progress, anyway," sighed Tom.
"Hark! I hear something," said Dick a little later. "Listen!"
They stopped their work and both strained their ears. A curious roaring and crackling came from overhead.
"That's odd," mused Tom. "What do you make of it?"
"I am almost afraid to say, Tom."