“I wish I’d broken his skull,” muttered the roughneck.

“We’d better leave her somewhere here,” remarked one of the better-dressed three.  “I don’t think the chief wants us to kill her—­yet,” he added, with an ominous glance at Elaine, who in spite of threats was not cowed, but was vainly struggling at her bonds.

“Well, where shall it be?” asked another.

They looked about.

“See,” cried the third.  “See that old boiler down there at the edge of the water?  Why not put her in there?  No one’ll ever think to look in such a place.”

Down by the water’s edge, where he pointed, lay a big boiler such as is used on stationary engines, with its end lapped by the waves.  With a hasty expression of approval, the rough-neck picked Elaine up bodily, still struggling vainly, and together they carried her, bound and gagged, to the tank.  The opening, which was toward the water, was small, but they managed, roughly, to thrust her in.

A moment later and they had rolled up a huge boulder against the small entrance, bracing it so that it would be impossible for her to get out from the inside.  Then they drove off hastily.

Inside the old boiler lay Elaine, still bound and gagged.  If she could only scream!  Someone might hear.  She must get help.  There was water in the tank.  She managed to lean up inside it, standing as high as the walls would allow her, trying to keep her head above the water.

Frantically, she managed to loosen the gag.  She screamed.  Her voice seemed to be bound around by the iron walls as was she herself.  She shuddered, The water was rising—­had reached her chest, and was still rising, slowly, inexorably.

What should she do?  Would no one hear her?  The water was up to her neck now.  She held her head as high as she could and screamed again.

What was that?  Silence?  Or was someone outside?

. . . . . . . .

Coolly, in spite of the emergency, Kennedy took in the perilous situation.

The lower end of the boiler, which was on a slant on the rapidly shelving beach, was now completely under water and impossible to get at.  Besides, the opening was small, too small.

We pulled away the stone, but that did no good.  No one could hope to get in and then out again that way alive—­much less with a helpless girl.  Yet something must be done.  The tank was practically submerged inside, as I estimated quickly.  Blows had no effect on the huge iron trap which had been built to resist many pounds of pressure.

Kennedy gazed about frantically and his eye caught the sign on the factory: 

Oxyacetylene welding Co.

“Come, Walter,” he cried, running up the shore.

A moment later, breathless, we reached the doorway.  It was, of course, locked.  Kennedy whipped out his revolver and several well-directed shots through the keyhole smashed the lock.  We put our shoulders to it and swung the door open, entering the factory.