"Yes, there is a hole here," Bertie said, feeling it; "the stone goes right in."

"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, senor!" 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, senor?" 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.

"Why should it have been left so?"

"Because the treasure they expected had never arrived. It is possible that when the Incas discovered the treasure in that chamber we searched, they may also have found this entrance. It may have been shown to them by one of the prisoners, and they may have broken the stone here into pieces as they broke that over the chamber afterwards.

Seeing what a splendid hiding-place it was, they may have, when the Spaniards first arrived, made another stone to fit, with the intention of using it for a hiding-place themselves. The fact that the stone was left so that it could be at once opened is conclusive proof to my mind that the treasure never came. That heap of sand, small stones, and chips of rock is another proof that they were ready to receive treasure, and it was probably swept out of the chamber that is behind here, and would, of course, have been removed when the treasure was put in and the door closed; but as the treasure never did come, it was left where it lay. However, we will now go and see. I have only kept you waiting because I did not want you to be disappointed."

One by one they crept through the opening. For four feet in, the pa.s.sage was the same width as the stone, but two feet deeper; then it at once opened into a large cavern.

"This wall was four feet thick, you see, Dias. Apparently squared stone was only used for the facing, as the stones are of irregular shape on the back. This would be a natural cavern, and a splendid hiding-place it makes. No doubt its existence was one of the reasons for building this castle."

The cavern was some twelve feet wide and thirty feet high at the mouth; the floor sloped up sharply, and the sides contracted, and met forty feet from the mouth. The floor had been cut into steps two feet wide, running across the cave and extending to the back. These steps were faced with a perfectly flat slab of stone. The cave was empty.

The natives uttered loud exclamations of disappointment and regret.

Harry had so thoroughly made up his mind that nothing would be found there that he surveyed the place calmly and in silence. Bertie imitated his example with some difficulty, for he too was bitterly disappointed.

"You see, Dias," Harry went on quietly, "this place was prepared to receive treasure. The steps have all been swept perfectly clean. You see, the gold could be piled up, and no doubt the steps were cut and faced with stone to prevent any gold-dust that might fall from the bags, in which, no doubt, it would be brought, and small nuggets, from falling into the cracks and crevices of the rock. I should say that in all probability they expected that treasure ship that was lost, and had everything in readiness for hiding the cargo here directly it came. It never did come. The door was shut as far as it could be without the bolt falling down and fastening it; then they waited for the ship; and if it did not arrive, other treasure might be brought by land. Well, it cannot be helped. So far we have failed. There may still be treasure hidden somewhere. We cannot say that we have searched the place thoroughly yet."

For another six weeks they worked hard. The wall was broken through in several places, but no signs of the existence of any other cavern or hiding-place was discovered.

"I should give it up," Harry said, when at the end of that time they were sitting gloomily round the fire, "but for one thing: I can see no possible explanation why a party of men should have been left here, and a guard kept, for perhaps a hundred years, perhaps more, and the stories about demons been circulated, and people who ventured to approach been murdered, unless there had been some good reason for it.

That reason could only have been, as far as I can see, that there was a treasure hidden here. I have turned it over and over in my mind a thousand times, and I can think of no other reason. Can you, Bertie, or you, Dias?"

"No," Bertie replied. "I have often thought about it; but, as you say, there must have been some good reason, for no people in their senses would have spent their lives in this old place, and starved here, unless they had some cause for it."

Dias made no reply beyond shaking his head.

"You see," Harry went on, "they kept up their watch to the end. There were those two skeletons of men who had died at their post at that curious window where nothing could be seen. I hate to give up the search, and yet we seem to have tried every point where there was a possibility of a hiding-place existing."

CHAPTER XIX

THE TREASURE

The next morning Harry said:

"I will go upstairs to that look-out place again. I have been up there pretty nearly every day, and stared down. I can't get it out of my mind that the key of the mystery lies there, and that that hole was made for some other purpose than merely throwing stones out on to any of those who might go in behind the rocks. I have puzzled and worried over it."

"Shall I come up with you, Harry?"

"No, I would rather you didn't. I will go up by myself and spend the morning there; some idea may occur to me. You may as well all have a quiet day of it."

He lit his pipe and went upstairs. Jose went off to the mules, and Bertie descended the ladder, and strolled round what they called the courtyard, looking for eggs among the rocks and in the tufts of gra.s.s growing higher up. Dias scattered a few handfuls of maize to the chickens and then a.s.sisted Maria to catch two of them; after which he descended the ladder and sat down gloomily upon a stone. He had become more and more depressed in spirits as the search became daily more hopeless; and although he worked as hard as anyone, he seldom spoke, while Harry and his brother often joked, and showed no outward signs of disappointment. An hour pa.s.sed, and then Harry appeared suddenly at the window.

"Bertie, Dias, come up at once, I have an idea!"

They ran to the ladder and climbed up. The excitement with which he spoke showed that the idea was an important one. "Now, Dias," he broke out as they joined him, "we know, don't we, that a part of the Incas'

treasure was sent off by boat, and the belief of the Indians was that it was never heard of again."

"That is so, senor. There was certainly a storm the day after it started, and, as I have told you, it was never heard of again. Had it been, a report of it would surely have come down."

"I believe, Dias, that the boat was dashed to pieces against that line of rocks outside the entrance to the pa.s.sage. We have reason to believe that the people here were expecting the treasure to arrive, and had the entrance to the cave in readiness to receive it. Certainly no better place could have been chosen for concealment. The boat may have been coming here when the storm broke and drove them towards the sh.o.r.e. They probably attempted to gain the mouth of the cove, but missed it, and were dashed to pieces against the rocks. The Indians on guard here no doubt saw it, and would be sure that the heavy sacks or boxes containing the gold would sink to the bottom. They would lie perfectly secure there, even more secure than if they had been removed and placed in the cave, and could always be recovered when the Spaniards left, so they were content to leave them there. Still, they obeyed the orders they had received to keep watch for ever over the treasure, and to do so knocked that strange hole through the wall and always kept two men on guard there.

"So it must have gone on. They and those who succeeded them never wavered. Doubtless they received food from their friends outside, or some of them went out, as you have done, to fetch it in. Then came a time when, for some reason or other--doubtless, as I supposed before, when the Spaniards swept pretty nearly all the natives up to work in the mines, and they themselves dared not issue out--the attempt to get food was made, when too late, by the men whose skeletons we found on the steps when we first came here; and the rest were all too feeble to repeat the experiment, and died--the two sentinels at their post, the rest in the room where we found them."

"Hurrah!" Bertie shouted, "I have no doubt you have hit it, Harry. I believe, after all, that we are going to find it. That is splendid! I shall dance at your wedding, Harry, which I had begun to think I never should do."

"Don't be a young a.s.s, Bertie. It is only an idea, and we have had several ideas before, but nothing has come of them."

"Something is going to come of this, I am convinced; I would bet any money on it. Well, shall we go and have a trial at once?"

"What do you think, Dias?" Harry said, paying no attention to Bertie's last remark.

"I think it is quite possible, senor. Certainly, if the Indians had been told to guard the treasure, they would do so always. You know how they kept the secrets entrusted to them whatever tortures they were put to. If the gold had been, as you say, lost amongst the rocks, I do think they would have still watched the place. I thought it strange that they should have made that hole, but when you said that they might have made it to throw stones down it seemed to me to be likely enough; but the other suggestion is more probable. Well, senor, I am ready to try it, but I am not a very good swimmer."

"My brother and I are both good swimmers, and we will do that part of the work. The hardest part will be getting it up, and you will be able to give us your help at that."

"Well, let us be off," Bertie said; "I am all on thorns to begin. We shall soon find it out. If it is there, it is almost certain to be at the foot of the rocks, though, of course, it is possible that the boat sank before striking them. At any rate, I feel sure she went down somewhere within the area that can be seen through that hole. It won't take many days' diving to search every yard of the bottom."

They hastily descended the ladder, and, divesting themselves of their clothes, swam out through the opening. Dias climbed up on the rocks, the others swam round by the ends of the barrier. The water was so warm that they would be able to remain in it for any time without inconvenience.

"We need not begin here, Bertie; we are outside the line of sight. From that hole I could not see the end of these rocks. We will start at the middle, and work in opposite directions."

On arriving off the centre of the wall both dived. The depth was about twelve feet, and as the water was perfectly clear, Harry could see four or five feet round him. He was obliged to swim carefully, for the bottom was covered with rocks, for the most part rounded by the action of the sea. For an hour he continued his search, by which time he had reached nearly the end of the line of rocks. Then he landed on a ledge of rock and sat down, calling to Bertie to join him.