es in it was poured into the holes the man had dug.
The boys could see now that it was not mortar, but concrete, which was
being used. To Dick the whole scheme was now plain.

The men poured a lot of gold dust into some concrete, and mixed it up
with water until it was about as thick as paste. Then they put it into
holes drilled in the rocky walls of the mine. The concrete hardened and
became almost like the rock itself. Then, when a blast was set off, the
rock, concrete and gold was all blown into small pieces, so that it
looked as if the ore was of good, gold-bearing quality, whereas it was
nothing but ordinary rock "salted."

That was how the men were working to fool investors. They had taken an
abandoned mine, from which all the gold had been dug, and, by this
ingenious method, made it look, to the ignorant, as though it was a
regular bonanza.

"Well," remarked Dick, in a whisper, "we've discovered the trick. I
guess dad's money and mine, too, is 'gone up the flume,' as the miners
say. But I'm glad----"

At that moment, Frank, who was balancing himself on a bit of rock, in
order to see better, stumbled and fell, making quite a noise. The men
turned as if a shot had been fired.

"What's that?" asked Smith, in a hoarse whisper.

"Some loose rock caving in," answered one of the men. "Come on, finish
up. We've only got one more hole to fill, and by that time Nash will be
ready to hoist us up."

"That wasn't falling rock!" declared Smith. "Boys, I believe someone is
spying on us. I'm going to take a look."

Seizing one of the torches he started toward where Dick and his
companions were hiding.

"Come on!" exclaimed the millionaire's son, pulling Tim and Frank by
the arm. "We've got to get out of this!"

They turned and ran, their footsteps echoing on the rocky floor of the
mine. They could hear Smith coming after them. His torch flashed around
the turn in the gallery. He caught sight of them.

"Stop!" he cried. "Stop or I'll shoot!"

CHAPTER XXVI

SIMON'S CONFESSION

Dick gave a hurried look behind him. He could see something shining in
Smith's hand--something that the light from the torch glinted on.

"Keep on!" hoarsely whispered Tim. "He can't hit us down here. Keep on!"

Stumbling, almost falling, their candles showing but faint blue points
of light as the flame flickered away from the wicks because of their
speed, the boys ran toward the bottom of the shaft.

"If we reach the ladder I t