But he noted that there was a line of shadow under the galleries.
Perhaps by keeping in this he could find another outward passage.
It was a terrible risk to take, but Frank did not hesitate.
“Come, Barney!” he said, “let us go down below.”
The Celt, without a word, followed Frank. But they had not descended three steps when the young inventor came to a startled halt.
A thrilled exclamation escaped his lips.
CHAPTER XII.
THE PURSUIT UNDERGROUND.
“Heavens!” he gasped. “We cannot go down now. Back for your life, Barney.”
The Celt, who would have followed his master anywhere, obeyed this command.
Back up the stairs they sprang.