If anything should happen to the dam, if it should burst, the enormous quantity of water held in leash by the structure would pour over the village and cover half the houses to their chimney tops.

Two bridges crossed the river at Elmvale; one at the village proper and the other just below the dam itself and about half a mile from the first mill, Barron & Brothers’ Thread Factory.

“Let’s take the upper road,” proposed Frenchy, as the car came within sight of the chimneys of the Elmvale mills.  “We’ve plenty of time before the noon whistle blows.  I haven’t been up by the dam since before we all joined the Navy.”

“Just as you fellows say,” Al responded, and turned into a side road that soon brought them above the mills on the ridge overlooking the valley.

“I say, fellows,” Whistler stopped whistling long enough to observe, “there’s a slue of water behind that dam.  S’pose she should let go all of a sudden?”

“I’d rather be up here than down there,” Al said.

“Oi, oi!” croaked Ikey, “you said something.”

“I wonder if they guard that dam as they say they do the munition factories,” Frenchy put in.

Al turned the machine into the road that descended into the valley by a sharp incline.  In sight of the bridge which crossed the river Whistler suddenly put his hand upon his chum’s arm.

“Hold on, Torry,” he said earnestly.  “I bet that’s one of the guards now.  See that fellow in the bushes over there?”

“I see the man you mean!” Frenchy exclaimed, leaning over the back of the front seat of the automobile.  “But he isn’t in khaki.  And he hasn’t got a gun.”

All the Navy boys in the automobile, even Seven Knott, saw the man to whom Whistler Morgan had first drawn attention.  The man had his back to the road.  He was standing upright with a pair of field glasses to his eyes.  His interest seemed fixed on a point along the face of the dam just where a thin slice of water ran over the flashboard into the rocky bed of the river.

CHAPTER II

THE STRANGER

For the life of him Phil Morgan could not have told why he was so keenly interested in that stranger.  He could not see the man’s face; he did not presume it was anybody he had ever seen before; nor had he any reason to be suspicious of the man.

Nevertheless he felt a little thrill as he first caught sight of the stranger, and this feeling spurred his exclamation to Torry, which lead the others’ attention to him.

After they had all seen the man, Phil added:  “Pull her down.  Let’s see what he is up to.”

Torrance stopped the automobile.  His chum was their acknowledged leader in most things, and all the other Navy boys were used to obeying Phil Morgan’s mandates without much question.  As told in the former books of this series, Morgan was an observant and level-headed youth, and his friends might have followed a much more dangerous leader in both work and play.