fingers sought the small projections of the gear on the inside of the door. He could no more budge the mechanism than a child could open a burglar-proof vault.
"It's no use," he moaned, and he sprawled at full length on the floor of the tank, for there the air was purer. As he did so his fingers touched something. He started as they closed around the handle of a big monkey wrench. It was one he had brought into the place with him. Imbued with new hope he struck a match and lighted his lantern, which he had allowed to go out as it burned up too much of the oxygen. By the gleam of it he looked to see if there were any bolts or nuts he could loosen with the wrench, in order to slide the door back. It needed but a glance ta show him the futility of this.
"It's no go," he murmured, and he let the wrench fall to the floor. There was a ringing, clanging sound, and as it smote his ears Torn sprang up with an exclamation.
"That's the thing!" he cried. "I wonder I didn't think of it before. I can signal for help by pounding on the sides of the tank with the wrench. The blows will carry a good deal farther than my voice would." Every one knows how far the noise of a boiler shop, with hammers
