and disappeared within it.

Judson pursued swiftly and without a moment's hesitation. Happily for
him, the tunnel was lighted at intervals by electric incandescents,
their tiny filaments glowing mistily against the wet and glistening
tunnel roof. Going softly, he caught a glimpse of the two men as they
passed under one of the lights in the receding tunnel depths, and a
moment later he could have sworn that a third, doubtless the man who had
leaped from the loading platform to run and hide in the shadows at the
mine mouth, passed the same light, going in the same direction.

A hundred yards deeper into the mountain there was a confirming
repetition of the flash-light picture for the ex-engineer. The two men,
walking rapidly now, one a step in advance of the other, passed under
another of the overhead light bulbs, and this time Judson, watching for
the third man, saw him quite plainly. The sight gave him a start. The
third man was tall, and he wore a soft hat drawn low over his face.

"Well, I'll be jiggered!" muttered the trailer, pulling his cap down to
his ears and quickening his pace. "If I didn't know better, I'd swear
that was Hallock again--or Hallock's shadder follerin' him at a good
long range!"

The chase was growing decidedly mysterious. The two men in the lead
could be no others than Flemister and the chief clerk, presumably on
their way to the carrying out of whatever plot they had agreed upon,
with Lidgerwood for the potential victim. But since this plot evidently
turned upon the nearing approach of Lidgerwood's special train, why were
they plunging on blindly into the labyrinthine depths of the Wire-Silver
mine? This was an even half of the mystery, and the other half was quite
as puzzling. Who was the third man? Was he a confederate in the plot, or
was he also following to spy upon the conspirators?

Judson was puzzled, but he did not let his bewilderment tangle the feet
of his principal purpose, which was to keep Flemister and his reluctant
accomplice in sight. This purpose was presently defeated in a most
singular manner. At the end of one of the longer tunnel levels, a black
and dripping cavern, lighted only by a single incandescent shining like
a star imprisoned in the dismal depths, the ex-engineer saw what
appeared to be a wooden bulkhead built across the passage and
effectively blocking it. When the two men came to this bulkhead they
passed through it and disappeared, and the shock of the confi