Looking down, as his eyes became accustomed to the gloom, he was able to see something of the nature of the roof, which must enclose the secret chamber. It was covered with dust and debris, but he was positive he could distinguish certain little bumps or lumps, which he shrewdly guessed to be thick diamond panes of glass, set in lead, and which, as he conjectured, furnished light to the room beneath. Entrance to this apartment seemed totally lacking from the roof, or else concealed by the dust of centuries. No staircase could he discover on the inside of the well, and he was about to relegate it to the limbo of unfathomable mystery, when a startling discovery gave him the key to the whole matter. It was, he saw, manifestly impossible to go down inside without falling, after which, if not killed by the shock, he would be left to starve at his leisure, while his friends searched the country-side for him. But if to descend within was impossible, to descend without presented almost as many difficulties. To go over the battlements as he had come, was well-nigh hopeless; but if he could walk along their inner rim for a foot or two, round the next embrasure, to the natural slanting entrance which was directly over the first step, the descent would be, comparatively speaking, easy. To rise from his present posture and assume a standing position on the twelve-inch rim of a structure eighty feet in the air requires a steady head, and though the Secretary was possessed of this, he did not at all relish the undertaking. It had to be done, however; but after his previous experience he determined to take no more risks, and reaching out from his position of vantage, he tested carefully every step of the way. At last only the slanting step remained. Reaching far over he touched it with his hand, when, to his horror, it practically revolved, now pointing down into the interior of the tower, its outward end pointing up. He shuddered when he saw the fate which the fortunate accident to the stanchion had caused him to escape. Had he descended in the regular way and stepped upon the slanting plate, the instant his foot passed its centre of equilibrium, it would have revolved, and without a doubt flung him down into the interior of the well. It was a cursed, mediæval trick, a fitting accompaniment to the inquisitorial horrors of those ages--an English _oubliette_. If the fall did not finish the daring invader of the tower--the inhabitants of the secret chamber doubtless had means to insure his end, or perhaps he was merely left to starve.