hen he came to his senses again, his first words were, "Milli, where are you?"

"My darling!" breathed a voice at his side. "Are you all right?"

"Yes," he replied. "Where are we? What has happened?"

"The entire system of locks must have crashed in and flooded the city," said she.

Instantly Abbott's mind grasped the explanation of this occurrence: their leaving open so many gates behind them had made it impossible for the few remaining gates ahead to withstand the terrific pressures of the ocean depths, and they had crumpled. But he did not tell Milli his part in this.

She continued, "I was pretty badly shaken up myself, but I've got this boat going again, and we're on our way out of the tunnel. See—I've found out how to work our searchlight."

He looked. A broad beam of light from their bow, illuminated the tunnel ahead of them.

Presently another beam appeared, shooting by them from behind.