But I must get a specimen or two of this sulphur for the ladies to see." He walked on cautiously.
"Mind!" said the captain.
"Oh, yes, I'll take care," came back out of the darkness.

"I can see my way yet, and the sulphur is wonderful.

These will do." A tapping noise followed from about fifty feet away; then the fall of a piece or two of stone, followed by a low hissing sound.
"Hear the steam escaping, Mark ?" said the captain.

"Ah, that's a good bit, as far as I can see.

Come, major." There was no answer.
"O'Halloran!" cried the captain, and his voice went echoing away into the distance, the name being partly repeated far in, as if whispered, mockingly by some strange denizen of the cavern.
"Major O'Halloran!" shouted Mark excitedly.