“That will do,” said the captain.  “And now that you are dressed, you can go inside and get me that woollen shirt and trousers that I use for a pillow, for I must take off these wet things.”

When the boy came back with the clothes, the captain told him that he need not say anything to his sister or Mrs. Cliff about the great danger he had been in, but before he had finished his injunction Ralph interrupted him.

“Oh, I have told them that already,” said he.  “They wanted to know where I had been, and it did not take a minute to tell them what a splendid swimmer you are, and how you came over after me without taking as much as two seconds to think about it.  And I let them know, too, that it was a mighty dangerous thing for you to do.  If I had been one of those fellows who were not used to the water, and who would grab hold of any one who came to save them, we might both have gone to the bottom together.”

The captain smiled grimly.  “It is hard to get ahead of a boy,” he said to himself.

It was late that afternoon when Captain Horn, with Ralph and the two ladies, were standing on the rocks in the inner apartment, trying to persuade themselves that they were having a cosey cup of tea together, when suddenly a scrambling sound of footsteps was heard, and Maka dashed through the two adjoining apartments and appeared before them.  Instantly the captain was on his feet, his gun, which had been lying beside him, in his hand.  Up sprang the others, mute, with surprise and fear on their faces.  Maka, who was in a state of great excitement, and seemed unable to speak, gasped out the one word, “Gone!”

“What do you mean?” cried the captain.

Maka ran back toward the passage, and pointed inward.  Instantly the captain conjectured what he meant.  Mok, the second African, had been stationed to watch the lake approach, and he had deserted!  Now the hot thought flashed upon the captain that the rascal had been a spy.  The Rackbirds had known that there were shipwrecked people in these caves.  How could they help knowing it, if they had killed Davis and the others?  But, cowardly hounds as they were, they had been afraid to attack the place until they knew how many people were in it, what arms they had, and in what way the place could best be assailed.  This Mok had found out everything.  If the boy could swim across the lake, that black man could do it, and he had gone out through the cleft, and was probably now making his report to the gang.

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.