For half an hour they worked with jacks and levers, and presently, with a deafening crack, the lock parted and the door was pushed open. There was revealed a room similar in shape and size to that which Mary Wenner had discovered; with this exception, that there were no stone benches, and in the centre of the apartment was a circular hole. Dick knelt by the side and held down his lantern; he heard the faint “clug” of water, and saw the light reflected at a considerable depth.

“A well,” he said. “All these old places have an interior well. There’s one in the Tower of London, in the centre of the dungeon.”

This room had been used as a prison at a distant period. At intervals along the walls hung rusted chains, with leg-irons attached. In one corner he saw a heap of rags, glimpsed a milk-white bone and shuddered. What was the history of this poor wretch who had been shut away from the light of God’s sunshine, to die miserably in this dark and dreadful place?

“Well, there’s nothing there,” said Gilder, peering over. Dick tied his lantern to the end of a cord and let it slowly down to the depths. Thirty feet below, as near as he could judge, the bottom of the lantern touched water. The old builders had built splendidly. The green, weed-grown sides of the well seemed intact. And then his heart almost stood still. A hand was thrust out, seemingly from the solid brickwork of the well, a white hand on which flashed and sparkled a single diamond that he knew well. And from below he heard a muffled voice; and in his agitation the cord which held the lantern slipped from his hand into the water.

He cursed aloud in his rage at his own criminal carelessness.

“Give me the other lantern!” he called, and pulling the other hand over hand, he untied it and flung it aside, fastening in its place the lighted storm lamp that Puttler handed to him. “And get a rope – quickly.”

But there was no rope nearer than Fossaway Manor, and he fumed in his impatience and would have made an attempt to slip down the treacherous sides of the well if Puttler had not restrained him.

After an eternity one of the detectives came running back carrying a rope, and, dropping one end, they fastened the other to a crowbar and placed this across the open doorway. Dick slipped down the rope, the handle of the lantern between his teeth. The sides were wet and slimy, and presently he came to the place where he had seen the girl’s hand.