“Well,” muttered the young inventor, “that is queer.”
Finally Frank raised his voice and shouted:
“Barney! Where are you?”
Again and again he shouted.
No answer came back. Now Frank was really alarmed. Cold perspiration burst out upon him.
“My soul!” he gasped. “It cannot be that he is lost.”
Fearful that this was the case Frank lost no time, but started to retrace his steps.
He kept carefully and closely to the wall of the passage and at intervals shouted loudly.
But each time no answer came.
Only the dull, muffled echoes. It was certainly an alarming matter.