Archibald may well have had some misgivings, for he was only a boy, and this happened more than sixty years ago, when ghosts and goblins had not come to be considered such indefensible humbugs as they are now. Nevertheless, he was of a singularly intrepid temperament, and besides he had passed the turning point in this adventure a few minutes ago. Nothing, therefore, would have turned him back now. Come what might of it, he would see this business to an end. It was, however, impossible to see anything without a light; it would be necessary to fetch one of the rush candles from the table in the corridor. It was a matter of half a minute for the boy to go and return; then he edged himself through the opening, and was standing in a kind of vaulted tunnel, directly behind the fireplace, the warmth of which he could feel when he laid his hand on the bricks on that side. The tunnel, which extended along the interior of the wall toward the left, was about six feet in height by two and a half in width. Archibald could walk in it quite easily. But, in the first place, he scrutinized the mechanism of the revolving mantelpiece. It was an extremely ingenious and yet simple device, and so accurately fitted in all its parts that, after so many years, they still worked together almost as smoothly as when new. After Archibald had poured a little of his gun-oil into the joints of the hinges, and along the grooves, he found that heavy stone structure would open and close as noiselessly and easily as his own jaws. It could be opened from the inside by using the silver rod in a hole corresponding to that on the outside; and, having practised this opening and shutting until he was satisfied that he was thoroughly master of the process, he put the rod in his pocket, pulled the jamb gently together behind him, and, candle in hand, set forth along the tunnel. After walking ten paces, he came face-up against a wall lying at right angles to the direction in which he had been moving. Peering cautiously round the corner, he saw, at the end of a shallow embrasure, a ponderous door of dark wood, braced with iron, standing partly open, with a key in the keyhole, as if some one had just come out, and, in his haste, had forgotten to shut and lock the door behind him. Archibald now slowly opened it to its full extent; it creaked as it moved, and the draught of air made his candle flicker, and caused strange shadows to dance for a moment in the unexplored void beyond. In another breath Archibald had crossed the threshold and arrived at the goal of his pilgrimage.