“Well, we must go on now. Perhaps it’s the way he came.”

“Couldn’t be, because he was not wet.”

“Well, I am right over my waist,” said Gwyn. “Shall we go on? We can swim if it gets deeper.”

“I say, let’s try it a little farther.” And holding the light well up, they waded on, with the water growing deeper, till it reached their chests and soon after their chins.

“Now then—go back or swim?” asked Gwyn.

“Oh, go on; Grip must know. I suppose the floor has gone down a good deal here.”

“Can you keep the lanthorn out of the water? If you can’t we must not go on; because it would be too horrible to swim here in the dark, and I don’t know whether I could keep on with only one hand swimming and holding Grip with the other.”

“He’d tow you along,” said Joe.

“Halt! Hold the light higher,” shouted Gwyn, and his words reverberated strangely.