“I see it,” said Bat, mildly. “But what is it?”
“Here is another just like it,” spoke Ashton-Kirk, “and running the same way. And there is still another, but not so heavy, between the other two.”
Sure enough, as Bat looked, he saw two deeply marked streaks, with a third not so pronounced between them; they held their relative positions and ran away in the same direction as far as his eye could follow.
“I get the three of them,” said Mr. Scanlon. “And once again I ask for the answer.”
“It looks,” and the glow of the torch began to follow the course of the lines, “as though our friend Alva, from the inn, had been here.”
“It’s got through,” said Bat, tapping his head dolefully. “It’s got through at last. These marks were made by the wheels of his chair—two big ones outside, and one small one in the middle.” There was a silence as the eyes of the big man followed the spreading rays of the torch. “Alva, you know, promised to drop in some time,” continued Bat. “And I can see that he’s a man of his word.”
The detective followed the wheel marks; they led directly across the vault to the east wall.
“Right slam into it,” spoke Mr. Scanlon from the darkness of a half dozen yards away. “Looks like they had an accident on the line.”
But Ashton-Kirk did not hear; he was too intent upon what was before him. Up the wall crept the shaft of light, and about four feet above the floor it rested upon a heavy iron ring.
“Hello,” said Scanlon, approaching and staring at the ring with interest. “Was it here that they chained the unhappy captive in the days of old?”