“Oh, no,” said the captain, “we can’t consider such wild schemes as that.  I have been thinking that perhaps there may be some sort of a tide in this lake, and in the morning we may find the water just as it was.  And, at any rate, it has not entirely deserted us, for in these pools at the bottom we can find water enough for us to drink.”

“I suppose I would not mind such things so much,” said Mrs. Cliff, “if they happened out of doors.  But being shut up in this cave with magical lakes, and expecting every minute to see a lot of bloodthirsty pirates bursting in upon us, is enough to shake the nerves of anybody.”

“Captain,” said Ralph, “I suppose you will not now object to letting me go in the morning to explore that opening.  I can walk across the bottom of the lake without any danger, you know.”

“Don’t you try to do anything of the kind,” said the captain, “without my permission.”

“No, indeed!” exclaimed Mrs. Cliff.  “Supposing the water were to suddenly rise just as you were half-way across.  Now that I think of it, there are springs and bodies of water which rise and fall this way, some of them in our own Western country, but none of them are as large as this.  What if it should rise in the night and flood the cave while we are asleep?”

“Why, dear Mrs. Cliff,” said Edna, “I am not afraid of the water’s rising or of the earth’s sinking.  Don’t let us frighten ourselves with imaginations like that.  Perhaps there may not even be any real thing to be afraid of, but if there should be, let us keep courage for that.”

The disappearance of the lake gave the captain an uneasiness of which the others had not thought.  He saw it would be comparatively easy for the Rackbirds to gain access to the place through the cleft in the eastern wall of the lake cavern.  If they should discover that aperture, the cavern might be attacked from the rear and the front at the same time, and then the captain feared his guns would not much avail.

Of course, during the darkness which would soon prevail there was no reason to expect a rear attack, and the captain satisfied himself with leaving Mok at his former post, with instructions to give the alarm if he heard the slightest sound, and put Maka, as before, in the outer passage.  As for himself, he took an early nap in the evening, because at the very first break of dawn it would be necessary for him to be on the alert.

He did not know how much he had depended upon the lake as a barrier of defence, but now that it had gone, he felt that the dangers which threatened them from the Rackbirds were doubled.

CHAPTER VIII

THE ALARM

It was still dark when the captain woke, and he struck a match to look at his watch.  It was three o’clock.

“Is that you, captain?” said a voice from the next room.  “Is it time for you to begin watch again?”