He turned to one of the metal boxes.  It was empty, and he set it down again.  Then he took up another box that was fairly heavy, and threw open the cover.

There, resting on some thick blotting paper, was a counterfeit plate—­a plate undoubtedly used for printing the backs of the spurious $100 bills!

Adam Adams could not help but gaze at that plate with interest.  How the Secret Service men had worked to bring that plate to light, and arrest the users!  And here he, in following up the clues of one crime, had stumbled upon the broad trail of another.

As he put the plate down, a noise reached his ears.  By instinct, he blew out the lantern and listened.  The noise was that from footsteps at a distance.  Then he heard a murmur of voices, quickly growing louder.

“They have discovered my escape,” he told himself.  And then he blamed himself for not having made better use of his time in an endeavor to get away.

He stepped out of the vault, and listened with strained ears.  The counterfeiters had separated, and were searching in all directions for him.

“If they come this way, I’ll have to fight,” he reasoned.  “I might as well die that way, as to be killed in cold blood.”

But then a sudden idea came to him, and as quickly as he had left the vault, he returned to it.  Footsteps were coming closer, and he had no time to spare.

One of the shelves of the vault was close to the top and very broad.  Up on this climbed the detective, and laid out at full length, as close to the wall as possible.  In front of him he held two of the wooden boxes containing the haired paper.

Somebody came closer, and he heard talking in the passageway at the foot of the stone steps.  A hand was placed on the door of the vault.

“Who left this unlocked?” came in Matlock Styles’ voice.

“Is it unlocked?” asked another of the band.

“Yes.”

“That is strange.  It was locked yesterday; I am sure of it.”

“Maybe that bloody rascal got here!” growled the Englishman.

“How could he work the combination?”

“Oh, some of those chaps are keener than you think.  Wait, hold up the light.”

Matlock Styles opened the door and gazed into the vault.  For the moment he saw nothing.

“Not here,” he said briefly.  “Come on; we’ll have to look elsewhere.”

CHAPTER XXVI

DOOMED TO DIE

“Wait a minute!” came from the other man, as Matlock Styles was on the point of coming out of the vault.

“What do you want?”

“I want to get some of that new paper.”

“Oh, you can get there after we have caught our man.”

“I’ll take it now—­it won’t take a minute.”

The man pushed his way into the vault.  He took hold of a box.  Then he suddenly backed away.