"Maybe he isn't coming here," breathed the boy. "Maybe he is only going
up to the dam!"

"To the dam?"

"That water-wheel business! It perplexes me," explained Whistler Morgan.

"We'll go up there and take a look!" exclaimed Mr. Santley, grabbing his
hat and banging down the roll top of his desk and locking it. "You've
got me all stirred up now, boy."

They hurried out of the office. Mr. Santley spoke in a low voice to the
armed guard on the front steps.

"If Blake comes here, hold him till I return," he said. "Do you
understand? _Hold him_--even if you have to knock him down and sit on
him."

"All right, sir," said the man, nodding grimly.

Mr. Santley started down the steps after the excited Whistler, who was
already getting into the automobile, the engine of which was still
running. At that instant the night was as peaceful as could be. The
valley below the high dam lay quietly under the light of the stars, and
a pale moon was just rising above the treetops.

Then, with a shock which electrified the atmosphere and seemed to make
heaven and earth tremble, a burst of flame rose at the foot of the dam,
not more than half a mile away!