Frank said nothing. He saw their matches were running out, and the thought of being left there in the darkness of that great cavern, with no means of procuring a light of any sort, was overcoming him and making it impossible for him to assume an air of carelessness and merry spirits.

Finally, when there were but a few matches left, Frank said:

“We’ll have to feel our way along and take chances, Harry. I am not going to use up all these matches, for there is no telling how valuable they may be later on.”

So, clinging to each other, they crept along inch by inch, lost in the Stygian darkness of the great cavern of the Sierras.

[CHAPTER XVII.—BROTHER AND SISTER.]

“There’s a light ahead, Harry!”

Frank uttered the words in an excited whisper, after they had been groping their way through the darkness of the great cavern for what seemed to be many hours.

Rattleton was greatly agitated.

“It is a light, sure!” he panted. “Frank, we’re all right at last!”

For some time they had heard a strange puffing sound that seemed smothered and far away, like the panting breathing of some subterranean monster. This was accompanied by a singular buzzing roar that sounded very uncanny.