rades toward the companionway. As he passed he grunted something to Caradoc. Madden's heart beat faster lest they should be discovered at this last hour. He had no idea what mission moved the Englishman, but he sensed that here was his destination. Smith made some reply in German, moved briskly ahead until he came to the small steel door. He laid his hand familiarly upon the bolts, shot them back, swung open the door. One of the men whirled about and stared back at this assured intruder. Smith stood aside and with a curt military gesture motioned Madden to enter. The American drew an uncertain breath, glanced at the three Germans out of the tail of his eye and stepped into the dark square. Caradoc followed him. The laborers went on updeck apparently satisfied.
An electric wire was let in through the door. Caradoc reached for it, followed it with his hand and presently turned a switch. Next moment a bright flood of light bathed the tubular chamber in which they stood.
Madden glanced about. He stood in a room whose roof formed a half circle over his head. The place seemed as full of machinery as a
