"Perhaps there is an opening to this tunnel. This seems promising."
The rush of cold air about their heads was soon quite evident. The boys' spirits rose forthwith and they proceeded through the tunnel more cheerfully.
"If air can get into this place we should be able to get out of it," said Frank. "Perhaps this tunnel is just another entrance to the mine."
"Let's hope so."
They continued, Frank flashing the light before him. The tunnel began to grow narrower. They had to crouch almost double in order to avoid bumping their heads on the rocky roof.
"Another minute or so and we'll know whether this place has an opening or not," called back Frank.
"It must have an opening! Where would that fresh air we feel be coming from if it hadn't one?"
"It might be coming through a small slit in the rocks. We can't depend on it too much. Ah! Here we are!"
His light had disclosed the fact that they were at the end of the tunnel. But his tones immediately changed to a murmur of disappointment when he saw that the tunnel ended in a sheer wall of cold, wet rock.
The boys crouched in silence gazing at the rock wall that seemed to crush all their hopes. The wall was a barrier that cut them off from all chance of reaching the sun-lit, outside world again.