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!

The glare of it blinded them; the reverberating explosion that followed almost immediately well nigh stunned them.  It was Ikey, standing in the tonneau of the car, and pointing a trembling arm toward the dimly distinguished wall of masonry, whose voice was first heard: 

“Look!  Look!  The dam’s broke!”

A balloon-shaped cloud of smoke had risen above the wall of masonry.  Beneath it the dam crumbled, dissolved, and poured away into the bed of the river like the changing picture in a kaleidoscope.

CHAPTER X

AHEAD OF THE FLOOD

Each one in the little group at the main entrance to the munition factory had cried out—­no doubt of that!  Indeed, Torry said afterward that he forgot to shut his mouth until his jaws were positively stiff.

Their fright did not deprive them of action, however; everybody immediately did something.

Inside the door, in the hall, hung the bell rope.  The bell swung in the cupola on the roof of the office building.  The guard dropped his rifle and sprang to seize this rope.  He slipped his foot in the loop and began to toll the bell as hard as he could.

“I’ll get Central and tell them what’s up!” gasped Mr. Santley, and turned to run back into his office to spread the news of the catastrophe by telephone.

Whistler plunged into the car, yelling to Torry: 

“Turn around!  Turn around!  Down the valley road to warn ’em!  Get a move on, boy!”

His chum was already starting the car.  It wheeled perilously in a sharp curve, and with honking horn hurtled down the road which followed the course of the river.

Without doubt the wall of the dam had been burst through by the explosion.  The immense mass of waiter held in leash would immediately pour through the opening.  The valley would be flooded!

As the car plunged across the main street of Elmvale people were running out of their houses and out of the stores, shrieking that the dam had burst.  They began to stream away toward the higher ground, stopping for none of their possessions.  If they saved their lives they would be fortunate.

Torry speeded up the car until she vibrated like a motor boat—­like the submarine chaser, No. 888!  They whirled along the half-lit road, the horn sounding its raucous warning, and the boys shrieking themselves hoarse.

People came to their doors and windows The flying Navy boys pointed behind them, repeating: 

“The flood!  The flood!”

The roar of the bursting dam was now in the ears of all the awakened people of the valley.  In three great explosions the weakened wall burst, and the water roared through.

Spouting through the wrecked masonry, the boys could see it spread below the barrier, half as high as the dam itself.  It would sweep the narrow valley clean of every small structure and of every living thing that could not get out of its path.