He shifted uneasily in his chair, then held his ear close to the loud speaker tuned to 200. A message came floating in to him across the air, a mysterious whispered message.
"Hello, Curlie," it said. "You don't know me, but you have seen me—"
Automatically Curlie's fingers moved the radio-compass backward and forward while his mind gauged the distance. His right hand scrawled some figures on a pad, and all the time his ears were strained to catch the whisper.
"I have seen you," it went on, "and I like your looks. That's why I'm talking now."
For a second the whisper ceased. There was something awe-inspiring about that whisper. As he sat in his secret chamber away up there against the sky, Curlie felt as if some spirit-being was floating about out there in the sky on a fleecy cloud and pausing now and then to whisper to him.
"I saw you," the whisper repeated. "You are in very grave danger. He is a bold and treacherous man. It's big, Curlie, big!" The whisper rose shrilly. "But you must be careful. You must not let him know the place where you listen in. I don't know where it is. But I do know you listen in. Be careful—careful—careful, c-a-r-e-f-u-l-" The whisper trailed off into space, to be lost in thin air.
Wiping the beads of perspiration from his face, Curlie sat up. "Well, now," he whispered softly to himself, "what do you know about that?
"One thing I do know," he told himself. "I'd swear it was a girl's whisper, though how you can tell a girl's whisper is more than I know. Question is: Which one is it—hotel station or the one that moves?"
For a moment his brow wrinkled in thought. Then with an exclamation of disgust he exclaimed:
"That's easy! I've got their location!"