retched the
length of the mill. Amalgamators and batterymen were going and coming
through all the pounding racket of this part of the establishment, but
the prospector had somehow managed to lose himself.

So suddenly and completely had Porter disappeared that it seemed little
short of magical. Frank took three or four steps from the foot of the
stairs, peering along the row of plates covered with dirty water from
the battery boxes, and looking back into the shadowy recesses under the
ore loft.

He was asking himself if Porter would have had time to get away into the
darkness back of the batteries, when a red-shirted amalgamator stepped
to his side.

"Lookin' fer Porter?" he yelled.

Frank nodded.

"He ducked out o' the door yonder," and the amalgamator, with a jerk of
his thumb, indicated an opening that led out into the night.

Ballard was nearest the door. He had heard the amalgamator, and whirled
like lightning and dashed out of the mill and into the darkness.

Frank was tight at his heels, while Clancy brought up the rear of the
little file of pursuers. The noise was not so deafening outside the
mill, but the boys were blinded temporarily by their quick transition
from the bright glow of the mill to the outer gloom. They stared around
them, but could see nothing of the prospector.

Ballard, however, heard something or other which gave him a clew. "This
way!" he shouted.

Frank heard his chum's feet swiftly crunching the sand and gravel, and
followed the sound. In a moment or two his vision cleared somewhat and
he was able to see several rows of huge wooden tanks. A plank incline
led to the top of one row, and Ballard could be distinguished racing up
the incline. Beyond Ballard, traveling at speed over a plank gangway
that spanned the tanktops, was a burly figure silhouetted against the
lighter gloom of the night. With a shout to Clancy, Merriwell hustled
after Ballard.

Those tanks were part of the cyanide plant, wherein the refuse of the
mill was treated with deadly cyanide of potassium for recovering what
little gold was left after the refuse, or "tailings," had come from the
stamp mill.

The cyanide plant, presumably, was familiar ground to Porter, whereas
the boys had never seen it before. In the gloom the prospector could
navigate across the big vats with something like accuracy, while the
boys carried on their pursuit at a tremendous disadvantage.

Recklessly Ballard ran on. Merriwell called a