It was Ralph calling to him.

Instantly the captain turned and hurried away, and as he went he extinguished his lantern.

When he reached his pail of water he picked it up, and was very soon joined by Ralph, who was coming to meet him over the bottom of the lake.
"I have been looking for you everywhere, captain," said he.

"What have you been after?
More water?
And you took a lantern to find it, eh?
And you have been ever so far into the cave.

Why didn't you call me?
Let me have the lantern.