At last Joanne realized that the explosion was not to come, that Blackton and his men were working to save them.

And now, as she listened with him, her breath began to come in sobbing excitement between her lips--for there was no mistaking that sound, that steady _beat-beat-beat_ that came from beyond the cavern wall and seemed to set strange tremors stirring in the air about their ears.

For a few moments they stood stunned and silent, as if not yet quite fully comprehending that they had come from out of the pit of death, and that men were fighting for their rescue.

They asked themselves no questions--why the "coyote" had not been fired?
how those outside knew they were in the cavern.

And, as they listened, there came to them a voice.