But he shut his eyes and listened for the last thing that he remembered.

He heard it presently, that low roll of the sea.

He was quite sure of one thing.

He was in the same submarine dungeon of the famous Castle of San Juan de Ulua.
His door was opened, and a man, not a soldier, came in with soup in a tin basin.

He uttered a low exclamation, when he saw that Ned was conscious, but he made no explanations.