The chink was very much larger than it had been before. There was no doubt about this. Then it had been barely wide enough to admit the package. Now he could easily thrust his whole arm into the opening. It was utterly unaccountable. By some incomprehensible means that crevice had been enlarged. The whole stone, he now saw, had been thrust forward several inches into the passage-way. It seemed as if nothing short of an earthquake could suffice to move from its place such a stone as that. In itself it appeared to be of vast size and weight, and below it, and above it, and on either side, were others equally vast. How was it possible for such a rock to be thus dislodged? By an earthquake? But nothing of the kind had occurred. He was a light sleeper, and was easily aroused by anything unusual. Could the castle have "settled?" Impossible. It was too old. It had long since shaken down into its deep bed. Still, old buildings do often settle, and in fault of any better explanation he was compelled to adopt something like this. In any event, there seemed very great danger that the package had been lost. Again and again he thrust his arm far in, but found only vacancy. Then he put his hand downward as far as he could. It touched something which felt like a stone pavement. This pavement was about eight inches lower than the one upon which he was. All this made the matter still more incomprehensible. But Harry had come forth to seek after this very thing, namely, some mysterious opening into a side-passage, and after the first surprise it occurred to him that this might be what he wished to find. And now the fact of the stone jutting forth became intelligible, though this new explanation promised ill for the safety of the package. It was evident that this stone was movable, and afforded in some way an entrance to this passage. It seemed strange that so vast a stone should be movable, yet there was the fact. Perhaps also it was less massive than it seemed. Perhaps it was a mere slab and opened like a door. But how? He now examined its surface with the most careful and minute scrutiny. In vain. Over all the surface and over all the edges there was nothing that indicated any means by which such a stone could be moved--nothing of the nature of hinges, and nothing of the nature of a handle, by which to grasp it so as to move it. Yet it was movable, and had been moved lately. Perhaps it could be moved without any help from a handle.