And certainly something was causing a pallor to spread over his features, and the cold sweat to break forth on his forehead. Harrison Grant knew what it was. From far away, the chimes of a church had sounded midnight and faded away into nothingness. Grant knew what Heinric von Lertz was thinking about--about that bomb and the fact that he was practically the only German left within the confines of the Ansonia Hotel. And so, that he might obtain a trifle of satisfaction against this cowardly plotter of Imperial Germany, he deliberately turned to Miss Mason and began the telling of an incident which could not be interrupted. And Grant knew how the passing of every second ate into the soul of Heinric von Lertz! Then a movement. Someone passed--and in passing, slipped a bit of cardboard into the cupped hand of Heinric von Lertz. Hurriedly the German shifted his hand to the interior of his silk hat, and under its protection, read the message. Involuntarily, his hands clutched. For there, scrawled on the cardboard, were the words: "Affair abandoned. Too dangerous." Von Lertz coughed, and at the sound, Harrison Grant and Dixie Mason turned. The German forced a smile. "I've changed my mind--er--that is, my headache's better," he announced. "We'll stay." "Thank you," said Harrison Grant, with quietly suppressed meaning, "my hopes are raised on a veritable bomb of happiness. Miss Mason, may I have this dance?" "Most certainly." Happily, bouyantly they went toward the ballroom, while Heinric von Lertz stared after them. "I wonder what that idiotic Yankee meant by a 'bomb of happiness,'" he mused, "Could he have known what I was plotting?" The thought brought back the memory of that card. Once again he glanced at it, then tore it to bits and stuffed it in his pocket. Then, throwing his coat to the check boy, he strode toward the ballroom. "At any rate," he growled under his breath, "they haven't stopped preparations at the shack." And at the same moment, the taxicab containing the old bomb maker had drawn to the curbing, forty blocks away, where another cab stood waiting. A figure came forth from the darkness and peered into the first cab. "Are you there, Kroner?" "Yes." "Alright. Everything's safe. Why don't you hurry?" "There's no need. I didn't use the bomb." "You didn't use it?" "You heard what I said," came testily from within the taxicab. "It's up to you to hurry. Get out to the shack and tell those men to work night and day to finish up their job!" A muffled conversation of an instant more, then the taxis parted. An hour later, as Harrison Grant again danced with Dixie Mason and Von Lertz seethed over the frustration of his scheme, a man hurried into a ramshackle old building on Staten Island, near Fort Wadsworth, aroused the slumbering figures there and pushed them toward a great thing of polished steel, nickel and brass that lay nine-tenths finished before them.