"Wait!" exclaimed the superintendent. He and Dexter dropped to their knees, and with eager hands began scooping away the musty-smelling earth. And in a moment they unburied an unyielding something that ran underground like a tenuous root.
"What?" demanded the colonel, peering near-sightedly into the trench.
Dexter had flattened himself on his chest to investigate. "Insulated wire!" he said in a suppressed voice. "A buried cable: The outer covering seems to have hardened—sort of petrified; but there's no doubt—"
"Let's see!" The colonel produced a knife from his pocket, thrust Dexter aside, stooped, and began to hack away at the moldy, taut-drawn strand. He cut through the outer surface, and the reddish glint of copper was revealed underneath.
He stood up with a sharp breath. "The old Western Union cable!" he muttered. "Trailed through the forest, and abandoned—more than a half century ago! Falling leaves drifting over it, decaying, forming new soil, burying it deeper and deeper, year by year! It must come all the way through the lower valleys, miles and miles of it."
"The line undoubtedly passes the cabin on the other side of the pass, where I first met young Preston, and the burned cabin, still farther south," put in Dexter in sober musing. "I dug around the one cabin the night Mudgett and the other chap were killed. But I didn't go deep enough. At the time I only thought it necessary to see if the ground had been recently disturbed. But of course it hadn't been. The cable was buried, not by the hand of man, but by the gradual work of the forest."
"Let's see where it goes!" said the colonel abruptly. He turned to Devlin. "Follow it up, please."
The constable resumed his digging, this time running his excavation along the line of the cable. The concealed wire led him straight to the cabin, and in a few minutes he had driven his trench to the base of the mud-daubed chimney.
Dexter had lingered in the background, an absorbed spectator, but when he saw where the cable led, he turned abruptly on his heel and almost ran back into the cabin. The four shackled prisoners watched his movements in furtive silence, but he paid no attention to them. The single bunk was built flush with the end of the fireplace, and he climbed up on the mattress and began to tap on the side of the plastered chimney. One of the stones moved before the pressure of his fingers, and he managed to pry it loose and draw it from place. And in the rudely built chimney was disclosed a dark, cubicle opening—a secret cubby hole in the masonry. He thrust his arm into the foot square space behind the stone, and drew forth a nickeled telephone instrument.
As he caught a breath of triumph, he heard a footstep behind him, and turned to see Colonel Devreaux staring over his shoulder. "Well, that seems to settle everything," remarked the old officer with a rueful expression. "The mysterious messages that passed back and forth through the wilderness! They had us guessing for a while, didn't they? But you've got it now."