At last they reached the end, where the passage terminated in a short flight of stairs. At the bottom of the stairs was a basin hollowed in the rock and this was fed by a spring of delicious water. They went up these and found a curious door made of stone. It was fastened with huge wooden bolts, a precaution, as they afterwards guessed, against rust. They passed through and discovered that the other side of the door was quite irregular and rough and the chamber in which they found themselves, if chamber it could be called, was like a natural cave. In the middle of the rocky floor was a great stone. Even this looked natural although they found that, as the book had said, it was so cunningly shaped and balanced that it would swing into a vertical position without much effort and allow of a man dropping through on one side of it. But the clever part of it was,--that what looked like accidental breaks in the stone were so arranged that certain other blocks could be fitted into them and the surrounding rock so that it could not be moved. If then by any accident any one should make his way into the chamber he would only think that he had come into a natural cave. Audry let herself down through the hole and with the help of Aline dropped to the ground, and found herself in a small fissure or cave, more or less blocked by underwood, where the stream ran through a little hollow or gully. She succeeded in getting back after making several unsuccessful attempts. “It is an excellent place,” said Audry, “but however shall we get him through that passage, it is so very narrow and so terribly long.” “We might even have to leave him in the cave room to-night,” Aline replied, “but I think it would be a good idea to count our steps on the way back. It will be interesting to know how long it is, and we shall also be able to tell in future how far we are at any moment from the end.” This they did and found that it was 1100 paces, which they reckoned would be as nearly as possible half a mile. Before they entered their bedroom again they experimented with the secret bolt that fastened the door, which acted perfectly, although, like everything else, they found that it would be the better for a little oil. It seemed a long evening, but at last it was time to go to bed. The children went upstairs and waited impatiently until they were quite sure that every one was asleep. They had managed to secrete a little food to take with them and also a few pieces of firewood, and put a little more in the secret room as they made their way out. They had already begun to get somewhat used to the stair and found even the long secret passage less alarming. It was a clear night although there was no moon, and they made their way without difficulty to the hollow tree. They found Ian Menstrie stiff with cold and in great pain, but his senses almost preternaturally alert.