Hans Hertig’s desire to get some of his old friends to enlist bore some fruit.  Three men promised to go down to the enlistment bureau on Saturday afternoon, when they had a half holiday.

The Seacove party then wanted to go to a dining-room for dinner; but Whistler excused himself.  He was hungry enough; but he “had other fish to fry,” he whispered to Torrance.

“Come around by the Upper Road—­same way we got here,” directed Whistler.  “I’ll meet you at the bridge.  Wait if I’m not there.”

“What is the matter with you, Whistler?” demanded Al.

But although Morgan went away without making answer, he knew that his chum would do as he was asked, and bluff off the others when they asked questions, too.

Philip Morgan hurried past the factories and the few houses which lay in this direction.  The land near the dam which had been built across the valley was so sterile that few people lived in this neighborhood.

Up on the ridges, on either side, were farms; but this was a wild piece of scrub at the foot of the dam.  One could jump a rabbit in it, or get up a flock of quail at almost any time during the hunting season.

Like most boys of Seacove, as well as Elmvale, Whistler was familiar with this stretch of untamed ground and plunged into it with full knowledge of its tangled brier patches and rough quarries.  He started diagonally for the dam, and in a brief time came to the edge of the shallow channel, which now carried the overflow of the huge reservoir behind the dam down to the cove.

As he followed this stream, he could not help thinking of the possibility of a break occurring in the high wall of masonry which loomed ahead of him.  If there should be any undiscovered weakness in the wall!  Or if an enemy should sink a charge of dynamite, or some other high explosive, at the base of the dam and blow a hole through it!

He did not see any one moving about the dam either above or below.  He knew that on the ridge, level with the top of the barrier, lived a man they called the dam superintendent.  He sometimes walked across the embankment, from end to end; a privilege forbidden to others.

But Whistler was quite sure that this dam superintendent seldom went to the foot of the wall, or examined the face of it for any break in the stonework.  Of course, the dam had stood secure for so many years that it seemed improbable that it would fail in any part now.

But Whistler Morgan was not considering any leakage of the water through the masonry which might endanger the foundation of the dam.  Such seepage must have shown itself long ago if the barrier had not been properly constructed.

It was of a sudden, unexpected, and treacherous blow-out that the young sailor was thinking.  That man in the bushes, who had seemed so desirous of hiding from the passers-by and whose interest in the face of the dam had been so marked, puzzled Phil and excited his suspicions.