ladies had gone inside, and heard him not. They appreciated to the full the danger from which they had been delivered. Ralph, too, had gone. The captain saw him on his post of observation, jamming the end of his flagpole down between two rocks.
“Hello!” cried the boy, seeing the captain looking up at him, “we might as well have this flying here all the time. There is nobody to hurt us now, and we want people to know where we are.”
The captain walked by the little group of Africans, who were sitting on the ground, talking in their native tongue, and entered the passage. He climbed over the barrier, and went to the lake. He did not wish to talk to anybody, but he felt that he must do something, and now was a good time to carry out his previous intention to cross over the empty bed of the lake and to look out of the opening on the other side. There was no need now to do this for purposes of vigilance, but he thought that if he could get out on the other side of the cave he might discover some clew to the disappearance of the lake.
He had nearly crossed the lake bottom, when suddenly he stopped, gazing at something which stood before him, and which was doubtless the object he had struck when swimming. The sun was now high and the cave well lighted, and with a most eager interest the captain examined the slimy and curious object on which his feet had rested when it was submerged, and from which he had fallen. It was not the horizontal trunk of a tree with a branch projecting from it at right angles. It was nothing that was natural or had grown. It was plainly the work of man. It was a machine.
At first the captain thought it was made of wood, but afterwards he believed it to be of metal of some sort. The horizontal portion of it was a great cylinder, so near the bottom of the lake that he could almost touch it with his hands, and it was supported by a massive framework. Prom this projected a long limb or bar, which was now almost horizontal, but which the captain believed to be the thick rod which had stood upright when he clutched it, and which had yielded to his weight and had gone down with him. He knew now what it was: it was a handle that had turned.
He hurried to the other end of the huge machine, where it rested against the rocky wall of the cavern. There he saw in the shadow, but plain enough now that he was near it, a circular aperture, a yard or more in diameter. Inside of this was something which looked like a solid wheel, very thick, and standing upright in the opening. It was a valve. The captain stepped back and gazed for some minutes at this great machine which the disappearance of the water had revealed. It was easy for him to comprehend it now.
“When I slipped and sank,” he said to himself, “I pulled down that lever, and I opened the water-gate and let out the lake.”
The captain was a man whose mind was perfectly capable of appreciating novel and strange impressions, but with him such impressions always connected themselves, in one way or another, with action: he could not stand and wonder at the wonderful which had happened — it always suggested something he must do. What he now wanted to do was to climb up to the great aperture which lighted the cavern, and see what was outside. He could not understand how the lake could have gone from its basin without the sound of the rushing waters being heard by any one of the party.
With some difficulty, he climbed up to the cleft and got outside. Here he had a much better view of the topography of the place than he had yet been able to obtain. So far as he had explored, his view toward the interior of the country had been impeded by rocks and hills. Here he had a clear view from the mountains to the sea, and the ridge which he had before seen to the southward he could now examine to greater advantage. It was this long chain of rocks which had concealed them from their enemies, and on the other side of which must be the ravine in which the Rackbirds had made their camp.
Immediately below the captain was a little gorge, not very deep nor wide, and from its general trend toward the east and south the captain was sure that it formed the upper part of the ravine of the Rackbirds. At the bottom of it there trickled a little stream. To the northeast ran another line of low rock, which lost itself in the distance before it blended into the mountains, and at the foot of this must run the stream which had fed the lake.
In their search for water, game, or fellow-beings, no one had climbed these desolate rocks, apparently dry and barren. But still the captain was puzzled as to the way the water had gone out of the lake. He did not believe that it had flowed through the ravine below. There were no signs that there had been a flood down there. Little vines and plants were growing in chinks of the rocks close to the water. And, moreover, had a vast deluge rushed out almost beneath the opening which lighted the cave, it must have been heard by some of the party. He concluded, therefore, that the water had escaped through a subterranean channel below the rocks from which he looked down.
He climbed down the sides of the gorge, and walked along its bottom for two or three hundred yards, until around a jutting point of rock he saw that the sides of the defile separated for a considerable distance, and then, coming together again below, formed a sort of amphitheatre. The bottom of this was a considerable distance below him, and he did not descend into it, but he saw plainly that it had recently contained water, for pools and puddles were to be seen everywhere.
At the other end of it, where the rocks again approached each other, was probably a precipice. After a few minutes’ cogitation, Captain Horn felt sure that he understood the whole matter: a subway from the lake led to this amphitheatre, and thus there had been no audible rush of the waters until they reached this point, where they poured in and filled this great basin, the lower end of which was probably stopped up by accumulations of sand and deposits, which even in that country of scant vegetation had accumulated in the course of years. When the waters of the lake had rushed into the amphitheatre, this natural dam had held them for a while, but then, giving way before the great pressure, the whole body of water had suddenly rushed down the ravine to the sea.
“Yes,” said the captain, “now I understand how it happened that although I opened the valve at noon, the water did not reach the Rackbirds until some hours later, and then it came suddenly and all at once, which would not have been the case had it flowed steadily from the beginning through the outlet made for it.”
When the captain had returned and reported his discoveries, and he and his party had finished their noonday meal, which they ate outside on the plateau, with the fire burning and six servants to wait on them, Mrs. Cliff said:
“And now, captain, what are we going to do? Now that our danger is past, I suppose the best thing for us is to stay here in quiet and thankfulness, and wait for Mr. Rynders. But, with the provisions we have, we can’t wait very long. When there were but five of us, we might have made the food hold out for a day or two longer, but now that we are ten, we shall soon be without anything to eat.”
“I have been talking to Maka about that,” said the captain, “and he says that Cheditafa reports all sorts of necessary things in the Rackbirds’ storehouse, and he proposes that he and the rest of the black fellows go down there and bring us some supplies. They are used to carrying these stores, and six of them can bring us enough to last a good while. Now that everything is safe over there, I can see that Maka is very anxious to go, and, in fact, I would like to go myself. But although there doesn’t seem to be any danger at present, I do not want to leave you.”
“As for me,” said Miss Markham, “I want to go there. There is nothing I like better than exploring.”
“That’s to my taste, too,” said the captain, “but it will be better for us to wait here and see what Maka has to say when he gets back. Perhaps, if Mr. Rynders doesn’t turn up pretty soon, we will all make a trip down there. Where is Ralph? I don’t want him to go with the men.”
“He is up there on his lookout, as he calls it,” said his sister, “with his spy-glass.”
“Very good,” said the captain. “I will send the men off immediately. Maka wants to go now, and they can come back by the light of the young moon. When they have loads to carry, they like to travel at night. We shall have to get our own supper, and that will give Ralph something to do.”
The party of Africans had not gone half-way from the plateau to the beach before they were discovered by the boy on the outlook rock, and he came rushing down to report that the darkies were running away. When he was told the business