teady and deafening.

Ore feeders were shoveling crushed ore into the stamp hoppers. Frank's
eyes ranged over the sweating, seminude, powerful figures as they
worked. He could see nothing of Nick Porter.

While Frank's eyes were searching the loft, Clancy nudged him with an
elbow. Frank turned, and Clancy made signs and pointed. Looking in the
direction indicated by Clancy's finger, Frank saw the slouching form of
Porter, the prospector.

He was sitting on a keg in an angle of the wall. He was leaning back
against the boards behind him, a cob pipe between his teeth. His eyes,
peering out of the jungle of beard that covered his face, were fixed
speculatively on the three boys.

Merry immediately stepped to the prospector's side. "Hello, Porter!" he
yelled in his ear.

The prospector probably grunted, although Frank could hear nothing.

"I want to talk with you for a few minutes," Merry went on, in a manner
calculated to disarm any suspicions Porter may have had. "Come up to the
super's office, will you?"

He stepped back. The prospector sat still on the keg for a moment, then
slowly knocked the ashes from his pipe and stood up. Frank was
congratulating himself that Porter was to make for Pardo's office
without any further persuasion; but in this he was mistaken.

Clancy stood on the prospector's right, Merry in front of him, and
Ballard on the left--between the spot where, Porter was standing and the
opening that led into the feed loft. The prospector slipped his pipe
into his pocket, moving in a slow, sluggish way that suggested
weariness.

He was not weary, however. Suddenly, without warning of any sort, he put
out one arm and threw Clancy sideways, so that he fell over a heap of
crushed stone. Another moment and Porter had leaped for a flight of
stairs and had vanished downward into the body of the mill.

It was all so quickly done that Frank was taken by surprise. The thought
flashed through his mind that Porter, unless he knew something about
Professor Borrodaile and suspected why the boys were there, would not be
showing his teeth in that fashion. An instant after the prospector had
disappeared down the stairs, Frank jumped after him. Ballard followed
close on Frank's heels; and Clancy, hastily picking himself up, stifled
an exclamation of anger and rushed after Ballard.

The stairs led down to the floor where the boxes were placed, and where
the plates, whose silver recovered the gold from the ore, st