"Well, I think, Bertie, you will find a hole in that end of the stone we moved that it will fit."
Bertie crept in, and felt along the top of the stone.
"Yes, there is a hole here about the same size as the stone, but it is not more than three inches deep."
"Then, that stone was the bolt, Bertie. You see it was pushed up, and the door then closed; and when the stone was exactly in its place, it would drop into the hole and keep it from moving, and nothing short of breaking up the bolt would give an entrance. It is lucky that we did not push it quite to; another quarter of an inch and that bolt would have fallen, and we could not have moved it unless by smashing the whole thing into bits. That was why they did not quite close the stone; they wanted to get in again."
"Here come the others!"
Maria had been washing some clothes in the stream, and they had therefore been longer in coming than if she had been in the room. They all looked greatly excited.
"So you have found it, señor!" Dias exclaimed in delight.
"We have found an entrance into somewhere, but I am afraid it will be as empty as the other chambers."
"Why do you think so, señor?" Dias asked in dismay.
Harry repeated the reasons he had given Bertie for his belief that the stone must have been left in such a position as to be easily opened when required.