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."