of high-class work.

Of late Jack and his young friends, though their pay went on, had little
work to do. Whenever a new boat was completed it was the task of the
submarine boys to take her out to sea and put her through all manner of
tests in order to determine her fitness. But there were days and days
when the submarine boys had naught to do but enjoy themselves as their
fancy dictated.

"Shall we sit down here?" asked Jack, as he and the tall German entered
the hotel office.

Jabez Holt stood behind the desk, bent over the register, on which the
Professor's name had been the only new one in a week. The old landlord
pretended to be busy, but he was covertly watching and listening.

"Sit here?" repeated Professor Radberg. "Ach, no! Come along with me."

There was something rather disagreeably commanding in the German's
invitation, but Jack merely smiled quietly as he followed in the
stranger's wake. Up the stairs they went. The Professor unlocked a
door, admitting himself and his guest to the outer of a suite of two
rooms. Once they were inside Radberg locked the door behind them.

"Come to the other room, Herr Benson," directed the Professor. The door
of this inner room the German also locked, remarking:

"Now, if the man, Holt, chooses to follow and listen, he can hear
nothing."