"This place is deep down under ground," answered Old Spicer, "and yet men have assembled here and slept here. That they could not do without plenty of fresh air. Now the question is, how is the place ventilated?"
Morgan hesitated a moment, then he exclaimed:
"Why, by means of the tunnel, of course."
"What tunnel?"
"The one through which we reached this vault."
"Wrong, George; the trap-door closes tightly, and the tunnel has no aperture in all its length."
"Then I give it up."
"That won't do, my boy, we must find the opening."
"All right, sir," and George immediately began the search in earnest.
But Old Spicer had already started with the same end in view, and rightly judging that the most likely place would be about opposite the door through which they had entered, he began his examination there, and almost immediately found what he was in search of.