“Ach, yes! of course,” replied Radberg.  “Now, we are beginning to understand one another.”

“Professor,” interrupted Captain Jack Benson, “we’ve had enough of joking.”

“Joking?  I assure you—­”

“Professor,” once more broke in the submarine boy, “I wouldn’t sell out my country’s flag for all the money you ever saw!”

For a few moments the Professor’s face was a study in consternation.  Then he broke forth, angrily: 

“Ach!  You are a fool!”

“I guess so,” nodded Jack, without resentment.  “That’s just the kind of fools we Americans are generally.”

Herr Radberg was a good enough reader of human faces to realize that, at all events, there was no use in continuing the conversation at present.

“Very good,” he growled.  “You can go.  I shall see your friends, instead.”

“When you get through with ’em you’ll think they’re idiots,” grinned Captain Jack Benson.

Herr Radberg wasn’t a fool.  Neither was he a rascal, expert in offering bribes.  Brought up within the wall’s of a German university, he would have been willing to lay down his life instantly for the good of the Fatherland.  Yet he couldn’t understand that men of other nations could be just as devoted to their own countries.  From Herr Professor Radberg’s point of view Germany was the only country in the world that was fitted to inspire a real and deep sense of patriotism.

“No harm done, Professor,” said Jack, moving toward the door, and turning the key to unlock it.  “I’m sorry you had all the trouble and expense of coming to Dunhaven on a useless errand.  Good-bye!”

“Ach!  You may go, but you will come back,” scowled the other.  “If not, your comrades will, I hope, prove to be young men of better sense and judgment.”

“Oh, they’ll listen to you,” smiled Jack.  “Good-bye!”

“I shall have two of you, anyway,” were Radberg’s last words before the door of the outer room closed and Jack’s footsteps sounded in the corridor.

CHAPTER II

“French spoken here”

“Well, what do you think of that?”

It was Eph Somers who put the question, and the time was some fifteen minutes later.

Captain Jack had met his two comrades up on the main street of the village.  He had told them, with a good deal of amusement, of his late talk with the German.

Hal Hastings didn’t say a word, but his eyes twinkled.

“I wouldn’t have minded,” laughed Jack, “but it was the Professor’s cock-sureness that I was to be Germany’s oyster.”

“Is he an old man?” asked Hal.

“Not very,” Jack answered.  “Perhaps not old enough to know better.  Anyway, if I were going to a foreign government, Germany would be about the last country.  Germany is our rival in building a large navy.  About every other month the experts in Germany sit down to figure whether they are anything ahead of us in the tonnage of warships, and, if so, whether there is any danger of our catching up with them.  Now, unless the Germans have a notion that they may need, to fight us one of these days—­”