XII. Let a Sailor Stick to Her Deck
XIII. The Trick is Easily Seen Through
XIV. Radwin Doesn't See His Best Chance
XV. The Goal of the Lightning Cruise
XVI. Jack Gives the Order. "Fire!"
XVII. The Message of Terror
XVIII. The Findings on the "Thor"
XIX. On the Other Side of the Forced Door
XX. Captain Jack Pulls a New String
XXI. Jack Meets a Human Fact, Face to Face
XXII. A Cornered Submarine Captain
XXIII. A Coward's Last Ditch
XXIV. Conclusion




CHAPTER I

WHY THE "DANGER" SIGN WAS UP


"Danger!"

That sign might have been over an air-hole in the ice; or it might have
been near rapidly moving shafting and belting in a factory.

As a matter of fact, the letters, white against the red paint on the door
of the shed, meant danger in the most terrible form. It was the sort of
danger, which, defied too far, would send one traveling skyward.