Curlie's fingers moved nervously over a tuner knob. He was sorely tempted to tune in and flash an answering "O.K.," if nothing more.
But, no, he drew his hands resolutely back. It was not wise. There was danger in it. This might be a trap. They might locate his secret tower room by that single O.K. Then disaster would follow.
The whisper came again: "You're clever, Curlie, awfully clever. The way you doubled over and turned yourself wrong side out was great! But please do be careful. It's big, Curlie, big!" again the whisper rose almost to speaking tone. "And he is a terribly determined man; wouldn't stop at anything."
The whisper ceased.
For a moment Curlie sat there lost in reflection, then he muttered savagely: "Oh! get off the air, you little whispering mystery, you're spoiling my technique. Your very terrible friend didn't send any message to-night and the one he sent before hasn't got us into any trouble. I've got to forget you and go after this moving fellow who sends 600."
As if in answer to his challenge the loud speaker to his right, the one tuned to 1200, began to rattle. Then, in the full, determined tones of a man accustomed to speak with authority there came:
"Calm night."
Three times, over five thousand miles of air, this great voice bellowed its message.
The silence which followed was ghostly. Cold perspiration stood out on Curlie's brow.
It was not necessary for him to calculate the location from which this message was sent. He knew that it had come from the hotel. And it had.