"Halt!" exclaimed Ford, stopping suddenly. "Another step, and perhaps we shall fall into some fathomless pit."

"Let us rest awhile, then, my friends," returned the engineer. "Besides, we ought to be thinking of returning to the cottage."

"Our lamp will give light for another ten hours, sir," said Harry.

"Well, let us make a halt," replied Starr; "I confess my legs have need of a rest. And you, Madge, don't you feel tired after so long a walk?"

"Not over much, Mr. Starr," replied the sturdy Scotchwoman; "we have been accustomed to explore the old Aberfoyle mine for whole days together."

"Tired? nonsense!" interrupted Simon Ford; "Madge could go ten times as far, if necessary. But once more, Mr. Starr, wasn't my communication worth your trouble in coming to hear it? Just dare to say no, Mr. Starr, dare to say no!"

"Well, my old friend, I haven't felt so happy for a long while!" replied the engineer; "the small part of this marvelous mine that we have explored seems to show that its extent is very considerable, at least in length."