All this flashed through the captain's brain in a few seconds. He set his teeth together. He was ashamed that he had allowed himself to be so tricked. That African, probably one of the gang, and able to speak English, should have been kept a prisoner. What a fool he had been to treat the black-hearted and black-bodied wretch as one of themselves, and actually to put him on guard!
Of course, it was of no use to go to look for him, and the captain had put down his gun, and was just about to turn to speak to the others, when Maka seized him by the coat. The negro seemed wildly excited and still unable to speak. But it was plain that he wanted the captain to follow him along the passage. There was no use in asking questions, and the captain followed, and behind him came Ralph, Edna, and Mrs. Cliff.
Maka was about to climb over the rocky partition which divided the passage, but the captain stopped him. "Stay here," said he, "and watch the passage. I will see what is the matter over there." And then he and Ralph jumped over and hurried to the lake. As they came out on the little platform of rock, on which the evening light, coming through the great; cleft, still rendered objects visible, they saw Mok crouching on his heels, his eyes wide open as usual.
The captain was stupefied. That African not gone! If it were not he, who had gone?
Then the captain felt a tight clutch upon his arm, and Ralph pulled him around. Casting eyes outward, the captain saw that it was the lake that had gone!
As he and Ralph stood there, stupefied and staring, they saw, by the dim light which came through the opening on the other side of the cavern, a great empty rocky basin. The bottom of this, some fifteen or twenty feet below them, wet and shining, with pools of water here and there, was plainly visible in the space between them and the open cleft, but farther on all was dark. There was every reason to suppose, however, that all the water had gone from the lake. Why or how this had happened, they did not even ask themselves. They simply stood and stared.
In a few minutes they were joined by Edna, who had become so anxious at their absence and silence that she had clambered over the wall, and came running to them. By the time she reached them it was much darker than when they had arrived, but she could see that the lake had gone. That was enough.
"What do you suppose it means?" she said presently. "Are we over some awful subterranean cavern in which things sink out of sight in an instant?"
"It is absolutely unaccountable," said the captain. "But we must go back to Mrs. Cliff. I hear her calling. And if Maka has come to his senses, perhaps he can tell us something."
But Maka had very little to tell. To the captain's questions he could only say that a little while before, Mok had come running to him, and told him that, being thirsty, he had gone down to the edge of the lake to get a drink, and found that there was no water, only a great hole, and then he had run to tell Maka, and when Maka had gone back with him, so greatly surprised that he had deserted his post without thinking about it, he found that what Mok had said was true, and that there was nothing there but a great black hole. Mok must have been asleep when the water went away, but it was gone, and that was all he knew about it.