nother of his jokes.
"May I ask when your ship leaves?"

"I'm thinking of leaving about midnight or a little after," stated
Jimmie, gravely. "It will depend somewhat on the wind and weather. If it
comes on to blow and the sea is rough I believe we'll get out on time.
However, if this breeze should die away, we may not go!"

"You're rather reversing the order of things," commented Ned. "Most
captains want clear weather and smooth seas for their departure!"

"Well, if it remains stormy, as it has every prospect of doing and you
want a swift ride, you just keep watch of your uncle!"

"Thanks!" laughed Ned. "You may surely count on me!"

"May we go along, too, Jimmie?" asked Harry.

"Sure, you may all go!" answered the lad. "But I warn you right now," he
added, "that you'll have to work your passage!"

"That suits me!" returned Harry, greatly amused at carrying on what he
considered as a pleasant joke to while away the time.

But to Jimmie, at least, the matter was not by any means to be regarded
as anything but a serious proposition. The lad had quickly formulated a
plan of escape. The very daring of his intended action was its best
guarantee of success. Failure meant disaster, but Jimmie was prepared to
risk all in the attempt.

For a time the lad said no more. His tightly shut jaws showed the
determination that possessed him. The others became absorbed in observing
and discussing the monster Zeppelin dirigibles, hence they said nothing
more upon the subject. There was much to attract their attention.

Directly they were summoned before the commander. As they entered the
cabin the Sturmvogel drew up alongside a dock.

"Young men," the officer began as the lads entered the cabin, "I regret
keenly the circumstances that seem to make it necessary for us to detain
you. I understand how anxious you must be to reach your homes, but it is
not possible to permit you to depart at this time. You will be given
every consideration during your stay at this place."

"Can't we go with you when you leave here?" asked Frank.

"No, that is impossible!" the other replied, shaking his head.

"Then maybe some other vessel will call and we can get passage on it? We
are not particular about the class of accommodations!"

"You forget that for some distance in every direction the sea is mined.
No vessels approach this island unless they know the channels."

"Then I guess we'll have to be contented," sighed the lad.

"Is Mackind