heavy affability. "I see that my men were in time. These swine of
Antillians are a tricky lot. I must apologize for them--my subjects."

The last word was pronounced with scathing contempt.

"We return greetings!" said Professor Stevens. "To whom, might I ask,
do we owe our lives, and the honor of this interview?"

Larry smiled. The old graybeard was up to his form, all right!

"You are addressing Herr Rolf von Ullrich," the flattered German
replied, adding genially: "commander of one of His Imperial Majesty's
super-submarines during the late war and at present Emperor of
Antillia."

To which the professor replied with dignity that he was greatly
honored to make the acquaintance of so exalted a personage, and
proceeded in turn to introduce himself and party. But Von Ullrich
checked him with a smile.

"The distinguished Professor Stevens and his charming daughter need no
introduction, as they are already familiar to me through the American
press and radio," he said. "While as for Mr. Hunter, your Captain
Petersen has already made me acquainted with his name."

At the mention of the commander of the _Nereid_, all three of them
gave a start.

"Then--then my captain and crew are safe?" asked the professor,
eagerly.

"Quite," Von Ullrich assured him. "You will be taken to them
presently. But first there are one or two little things you would like
explained--yes? Then I shall put to you a proposal, which if
acceptable will guarantee your safe departure from my adopted
country."

Whereupon the German traced briefly the events leading up to the
present.

* * * * *

During the last months of the war, he had been placed in command of a
special U-boat known as the "mystery ship"--designed to resist
depth-charges and embodying many other innovations, most of them
growing out of his own experience with earlier submarines.

One day, while cruising off the West Indies, in wait for some luckless
sugar boat, he had been surprised by a destroyer and forced to
submerge so suddenly that his diving gear had jammed and they had gone
to the bottom. But the craft had managed to withstand the pressure and
they had been able to repair the damage, limping home with a bad leak
but otherwise none the worse for the experience.

The leak repaired and the hull further strengthened, he had set out
again. But when in mid-Atlantic the Armistice had come, and rather
than return to a defeated country, subje