"I'm sure of it," Ned whispered back. "Ah, here are more steps."

They had reached the stairway which led down to the hall of the submarine cells, and still feeling their way they ascended it cautiously. As they rose the air seemed to grow fresher, as if they were nearing the openings by which it entered.

"Those fellows who took our places must have left a lamp or a lantern standing somewhere here at the top of these steps," whispered White. "The man who carried the tray could not have gone down them without a light."

"It's probably here," said Ned, "burned out or blown out by a draught of wind."

He smelled a slight smoke and in a niche carved in the stone he found the lamp. The wick was still smoking a little.

"We'll leave it as it is," said Obed White. "Somebody may relight it for those men when they come back again, but that won't be for several hours yet."

Three more steps and they reached the crest of the flight, where they were confronted by a heavy door of oak, ribbed with iron. Obed gently tried the key that they had seized, but it did not fit.

"They must have banged on the door for it to be opened whenever they came back," said Obed. "Now I shall use my fork which is sure to turn the lock if I take long enough. I wasn't the best watch and key maker in Maine for nothing. If first you don't succeed, then keep on trying till you do."

Ned sat down on the steps while White inserted the fork. He could hear it scratching lightly for a minute and then the bolt slid. The boy rose and the man stepped back by his side.

"Draw your pistol and have it ready," he said, "and I'll do as much with the old musket. We don't know what's on the other side of the door but whatever it is we've got to meet it. Thrice armed is he who hath his weapon leveled."