promptly. I have something very important to communicate to
you--something that I hope will make up for the loss you suffer
in being taken away from college in the middle of the term. Or,
to be more correct, Mr. Roumann will impart most of the
information, for it is at his suggestion that I sent for you."

"Are these the young assistants of whom you spoke?" asked the
other man, and the boys noticed that he was a big, burly German,
with a bushy, gray beard, and penetrating, blue eyes.

"This is Jack Darrow," said the professor, indicating the stout
youth, "and the other is Mark Sampson. They have lived with me
several years now, and we have had many adventures together."

"Ha! Hum! Yes!" murmured Mr. Roumann, then he said something in
German.

"I beg your pardon," he went on quickly. "I have a habit of
talking to myself in my own language once in a while. What I
said was that I did not know the lads were so young. I am
somewhat apprehensive--"

"Do not be alarmed on the score of their youth," cried Professor
Henderson. "I assure you that they have had a peculiar training,
and, in some scientific attainments, they know as much as I do.
You will not find them too young for our purpose, in case we
decide that the thing can be done."

"I tell you it can be done, and it shall be done," insisted Mr.
Roumann.