ng them were Joe, Bill,
and their helpers.

These last discussed the subject without arriving at any definite
conclusion when the time to separate arrived.

On the following morning work was resumed in the cutting. The loose
earth having been cleared away, a reasonably solid roof was put up, and
once more the tunneling operations were pushed forward vigorously.

All hands were on the alert for a repetition of the mysterious cries,
but nothing was heard save the noise of the picks and shovels, with now
and then a muffled crash as fragments of the vein were detached by
blasts.

During the "nooning" lunch was eaten in the cutting, and while they were
sitting quiet a singular vibration of the earth could be felt.

"It seems as if some one was digging directly beneath us," Fred said,
when the little party ceased eating to gaze at each other in surprise.

"Most likely there's a line of slate just under our feet, an' brings the
sound from the other drift," Joe replied promptly.

"That's about the size of it," Bill added; but the boys noticed that
both the men listened from time to time as if in great perplexity.

The peculiar tapping continued without interruption, and before the time
of rest had more than half expired Joe said, as he arose to his feet:

"Come on, lads. We're close to the old drift, an' after that's been
opened we'll have another look around, for I want to find out what these
queer noises mean."

Each one worked with the utmost rapidity, and when another hour had been
spent Bill's pick broke through the barrier of earth.

"That ends the job, an' now to see how the air is."

The miner had hardly ceased speaking when a huge volume of gas burst
through the aperture, nearly suffocating the party and extinguishing the
lamps instantly.

"Jump to it lively, boys!" Joe cried hoarsely, as he began shoveling
back the earth. "When you can't work any longer get a breath of fresh
air in the drift."

There was every danger that the lower level might be so filled with the
noxious vapor as to cause an explosion, and both men and boys labored
manfully.

All were working blindly, but the general direction of the aperture was
known, and the greater portion of the earth could be thrown with a fair
degree of accuracy.

Ten minutes passed and the flow of foul air was partially checked. Twice
had each person been forced to retreat to the main drift, and Fred was
about to go for the third time when it seemed as if