They found the artificial passageway to be at no point less then five feet in height, and on the dirt surface of the flooring were imprints leading them to believe that many persons had passed back and forth through there at a comparatively recent date. Its course was almost directly northward, and the lads could at all times see some distance ahead. Nevertheless they proceeded warily, not knowing what sort of a trap might be set for them. The air was heavy and damp, but gave them no great discomfort until they had proceeded for several hundred yards, and then they concluded that the tunnel, whatever its purpose, had but one outlet, and that was the one through which they had entered.
“Do you realize where this is leading?” Tom asked presently, as he half turned toward Harper.
“Unless my sense of direction is all off,” George responded, “directly under Thiaucourt.”
“Straight as an arrow,” Tom added, “and we ought to be almost under the town by this time.”
No longer could they hear the dull rumble of the guns, and their own voices echoed and re-echoed down the cavernous passageway, the only interruptions in an otherwise dead silence.
“Hello!” exclaimed Tom suddenly, in a note of new surprise, and an instant later the far wall flung back the word at them as though someone there were repeating it in mockery. There was something unpleasant about the situation. It was like wandering around aimlessly in the dead of night in an abandoned house reputed to be haunted, not knowing what startling surprises awaited one at any moment.
Tom’s exclamation escaped him when he noticed that the tunnel apparently came to a dead end about twenty-five feet ahead. A moment later, however, it was apparent they were approaching a right-angled turn.
Tom extinguished his own light to see if any ray came from down this new passageway, but there was nothing but pitch blackness, in which neither lad could discern the outline of the other.
Snapping it on again they proceeded slowly until Tom stood within a foot of the abrupt turn in the wall. The new tunnel ran directly to the right of the direction in which they had been approaching. With a sudden forward thrust of his head, Tom took a quick survey of what lay beyond.
He drew back with a gasp, and his free hand fell upon Harper’s arm.