ve minutes later this had been done. Benson turned to Lieutenant
Abercrombie, saying:

"I must apologize for not having thought to return your revolver as
soon as we entered."

"I would beg you to keep the weapon, dear old fellow, if it would be
of any use to you," replied the British officer.

And now Hal and Eph found chance to explain that they, worried by Jack
Benson's disappearance, had at last started down to headquarters to
see if they could learn of any mishap to him, or of any other explanation
for his long absence.

"Well, it's all over now," muttered Hal. "Millard--or Graves--or
whatever other name the fellow may be using at this moment--is safe
in a cell downstairs."

"We thought, once before, that we had him bottled up safely," chuckled
Lieutenant Jack. "Mr. Abercrombie, how am I ever going to express my
thanks to you?"

"I should feel extremely insulted, dear old fellow, if you thought it
necessary to thank me," retorted the Briton, heartily.

"It will be dark, soon," interposed Lieutenant Ulwin. "I suggest that
the best thing any of us can do is to turn toward the club. I feel
certain that the chef will have a famous dinner there to-night."

"We haven't any evening clothes, either citizen or uniform, in
Washington," interposed Jack Benson, who knew something of the
formalities of the service during the dinner hour.

"Come, just the same," begged Ulwin. "The members don't expect too
much of fellows who are traveling."

Jack was glad of the walk, because it helped to take the stiffness out of
the knee that had been struck.

"You let the cab driver go, did you!" asked Eph, as the submarine boys
walked along together.

"Yes," nodded Jack. "I had no orders concerning anyone like him. He's
only some worthless character hired for the job. He didn't have any
hand in the bigger job of collecting and selling harbor defense plans,
you may be sure."

As the party re-entered the club they found a large attendance. Nor
was it many moments before a be-moustached German officer approached
the group.

"Oh, Herr Ulwin," he asked, "can you oblige me by excusing Herr Benson
for a moment or two? And will you come with me, Herr Benson, to meet
a friend who wishes to shake your hand?"

Jack slipped away with the German officer, who conducted him to another
room.

"I think you have met my friend before," explained the German, and
wheeled the submarine boy straight up in front of Herr Professor Ra