"Nothing; only I shall swim for it if the worst comes to the worst. I suppose you can't swim under water at all?"

I did not answer his question. I scarcely heard it: cold beads were bursting through my skin.

"Why should the worst come to the worst?" I whispered. "We aren't found out, are we?"

"No."

"Then why speak as though we were?"

"We may be; an old enemy of ours is on board."

"An old enemy?"

"Mackenzie."

"Never!"

"The man with the beard who came aboard last."