"Yes, senor," Maria said; "but when they find that they can't get in here, they will come in through the openings above."

"So they will; I did not think of that. But when they once find that they cannot get out here in the evening, they will go out where they came in, and we shall have no more trouble with them. I don't know whether they are good to eat?"

Maria gave a little cry of horror.

"Oh, senor! I could not eat such horrible things!"

"Their appearance is against them, Maria; but when people eat alligators, frogs, snakes, and even rats, I don't see why a bat should be bad. However, we won't touch them unless we are threatened by starvation."

"I should indeed be starving before I could touch bats' flesh, senor."

"Well," Harry said, "if people eat monkeys, rats, and squirrels--and it seems to me that a bat is something of a mixture of the three--one might certainly eat bats, and if we are driven to it I should not mind trying; but I promise you that I won't ask you to cook them."

They chatted for another hour, and then Maria went off to her corner.

The brothers spread their beds by the fire, and Jose had his blanket and poncho, and it was arranged that any of them who woke should put fresh logs on the fire.

They were all roused just before dawn by a squeaking and twittering noise. They threw on fresh logs, and as these blazed up they could see a cloud of bats flying overhead. They kept on going to the doorway, and when they found they could not get through they retired with angry squeaks. The light was gradually breaking, and in a few minutes all had flown out through the opening. Harry and his brother followed them, and could see them flitting about the upper windows. Presently, as if by a common impulse, they poured in through the various openings.

"I don't suppose we shall see any more of them," Harry said, "and I own that I shall be glad. There is something very weird in their noiseless flitting about, and in the shadows the fire casts on the ceiling."

"They are a great deal larger than any bats I have seen," Bertie said.

"I have seen as large, or larger, at Bombay and some of the towns on the coast."

"They bite people's toes when they are asleep, don't they?"

"Yes, the great vampire bat does, but I have never heard of any others doing so. They live on insects, and some of them are, I believe, vegetarian."

"Are vampire bats found here?"

"I do not think so; I fancy that they inhabit Java and other islands in the Malay Archipelago. However, they are certainly rare, wherever they come from, and you can dismiss them altogether from your mind."

"I was glad when I heard your voices, senors," Maria said when she appeared a quarter of an hour later. "I knew they would not hurt me; but I was horribly frightened, and wrapped myself up in my blanket and lay there till I heard you talking, and I heard the logs thrown on the fire; then I felt that it was all right."

"I don't suppose they will come again, Maria."

After drinking a cup of coffee, with a small piece of maize cake, Bertie said:

"What is the programme for to-day?"

"We can't do much till Dias comes back. We may as well go down and have a look at the lower rooms. I don't think there is much dust on the floor there, but while Jose is away looking after the mules we will cut enough bushes to make a couple of brooms. We shall want the place swept as clean as possible, so that we can look about, but I don't think there is the least chance of our being able to move the stones. Before we do anything we will go down to the pool and have a swim, and dive out through the entrance and have a look at those rocks."

"That is right," Bertie said. "I was longing for one yesterday morning, but of course the first thing to be done was to examine this place."

"Would it be safe for me to bathe, senor?"

"Quite safe, Maria; the slope is very gradual, and you need have no fear of getting out of your depth suddenly. We will be off at once, Bertie."

CHAPTER XVII

AT WORK

Harry and his brother went to the edge of the pool, where they undressed and waded out. They found that the bottom of the pa.s.sage sloped more gradually at the edge of the water than it did higher up, and they were able to walk out till they came to the point where the roof dipped into the water. They dived, and in a few strokes came up beyond the roof.

"This is glorious!" Bertie said. "We have often bathed in pools, but this is a different thing altogether. It is more than a year since we had our last dip in the sea, the day we arrived at Callao."

Although there was little or no wind, the rollers were breaking on the line of rocks outside, pouring over the lower points in volumes of foam, and coming in broken waves up the pa.s.sage.

"We mustn't go beyond the point, Bertie, or we may be dashed against the foot of the cliff. We will climb up that rock to the left; it is not too steep, and I think we can manage it. From there we shall get a good view of this side of the house and of the situation in general."

It required considerable care to climb the rocks, and more than once they hurt their feet on sharp projections. The top of the rock, however, was smooth by the action of time and sea, and they were able to sit down on it in comfort.

"The castle is just as you described it, Bertie; and certainly no one sailing past, however close he came outside these rocks, would be able to detect it. No doubt the stone of which it is built is the same as that of the cliffs. Most likely it was taken from the ravine where the pa.s.sage now is, and had fallen from the arch above. It might have been more noticeable at first, but now it is weathered into exactly the same tint as the cliffs. The openings are very dodgily placed, and a stranger would not dream that they went many inches in. Now, from where we stand we can look up into that curious opening on the top story. I have been puzzling over that ever since I saw it, but can't think of any possible reason for its having been cut like that, except to enable them to throw stones on to any boat that came into this pa.s.sage behind the rocks; and yet that can hardly have been the case, for, as I remarked, there are no stones piled up there. Certainly they had a very large number of arrows, but stones would be very much more useful than arrows against a boat almost under their feet. However, that does not concern us now. This line of rocks must greatly aid in hiding the house from the sea. They are higher than you thought they were, looking down at them from above. We are quite thirty feet above the water, and at two or three points they are at least ten or twelve feet higher. Of course a short way out no one would be able to see that they were detached from the cliff, or that there was any pa.s.sage whatever behind them.

"Besides, they break the force of the waves. If it was not for them it would be impossible for any boat to come up close to the face of the house, and a heavy storm might even break down the wall altogether. A tremendous sea would roll in here in a westerly gale; and if it hadn't been for these rocks it would have been necessary to build the lower part of the house absolutely solid to resist the sea. It is possible that the rocks were higher than they now are when the place was first constructed, in which case the house might have been almost entirely hidden from sight. Well, we may as well go back again, Bertie; we know all there is to be known about this side."

They swam back into the tunnel, dressed, and went out.

"We have come out, Maria," Bertie called. "The coast is clear for you.

The water is not so deep as we thought it was, and you can walk out to the point where the roof comes down on to the water without getting out of your depth."

It did not take them long to cut a number of switches to serve as brooms, and a couple of handles. They carried them up into the house, and lashed the switches firmly on to the handles. The work was rough, but the brooms when completed were large, and, although not strong enough for heavy work, would do well to sweep aside the thin layer of almost impalpable dust on the floor below.

"Shall we take wood down there, Harry?"

"No; I think a fire would be a drawback rather than an a.s.sistance. It would be very valuable if we were working at one spot, but it could give no general light in a place a hundred feet long. We will take a torch down, and hold it and sweep by turns. We shall only want, to begin with, to make a clear path a couple of feet wide down the middle.

Of course later on we shall clear it all. That will be sufficient to enable us to see how the floor is constructed, whether with big blocks or small ones, how closely they are fitted together, and so on. It is certainly unlikely that we shall find any indication as to where chambers exist."

It took but a very short time to clear the path; the dust was so light that one sweep of the broom cleared it away. When they got to the farther end they returned to examine the floor. For four or five feet from the cistern the rock had been evidently untouched, except to cut off any projecting points. Then there was a clear line running across the path. Bertie held the torch down close to it. Harry knelt down and examined it.

"This is a clean cut, Bertie. It is evidently solid above this, but the stone is not quite the same colour on each side of it, and it looks as if they had cut away the rock here and begun to build so as to keep the floor level. The cut may be six inches deep and it may be a foot, that doesn't matter. The face of this stone is very smooth, but it is not cut; it is, I think, the face of the natural fracture. Move the torch along and let us see where the next join is. Ah, here it is!"

The slab was four feet across.

"You had better sweep the dust off both ways, Bertie, so that we may see what size it is."

It was, they found, about eight feet long.

"It has straight edges, Harry, almost as straight as if it had been sawn."

"Very likely it was sawn, Bertie; They could have had no tools that would cut a hard stone like this regularly, but as they were certainly clever builders they must have employed some means to do it. Possibly they used a saw without teeth, for however much they might have hardened the copper, the teeth could not have stood, but if they had a hard copper band fixed like the saw some masons use, and kept the stone moistened with fine sand, they might have cut into it. Of course it would have been a slow process; but they would not have needed to go far into the stone, for when they got down two or three inches they might have broken it through by dropping a heavy weight on the end. It would not have mattered if the fracture had not been straight below the cut, for only on the surface would they have wanted to fit accurately to the next stone. In another way they might have got a straight edge, that is, by driving very dry wedges into the cut made by the saw, and then moistening them. I know that great stones can be split in that way. They may have used both methods. However, it doesn't matter to us much how they did it. It is clear that they could in some way or other cut stones. As they took the trouble to do so here, we may conclude that they were anxious to have a smooth floor that would be extremely difficult to get up.

"They would never have taken all this trouble if they had merely been making a floor for a cellar. For that purpose it would only have been necessary to throw rocks and stones of all sizes into the vacant s.p.a.ce below, and when it was nearly full, to level it with small stones and sand. That they chose to undertake such tremendous labour as the making of so regular a floor as this must have been, shows that they had some very strong motive for doing so."

Going carefully along the track they had cleared, they found that the stones were of different sizes; some were but two feet wide, others as much as ten, but all fitted so closely together that it was difficult to see the joints.