themselves. I never see agents, you know, Sylvia."

Sylvia declared her belief that the stranger was not an agent, and the
professor glanced at his book reluctantly.

"Very well; I will see him. I wish you would run down these references
for me, Sylvia. Don't trouble about those I have checked off. It can't
be possible I am following a false clue. I'm sure I printed that article
in the 'Popular Science Monthly,' for I recall perfectly that John Fiske
wrote me a letter about it. Come home when you have finished and we'll
take our usual walk together."

Professor Kelton had relinquished his chair in the college when Sylvia
came to live with him twelve years before the beginning of this history,
and had shut himself away from the world; but no one knew why. Sylvia
was the child of his only daughter, of whom no one ever spoke, though
the older members of the faculty had known her, as they had known also
the professor's wife, now dead many years. Professor Kelton had changed
with the coming of Sylvia, so his old associates said; and their wives
wondered that he should have undertaken the bringing-up of the child
without other aid than that of the Irishwoman who had cooked his meals
and taken care of the house ever since Mrs. Kelton's death. He was still
a special lecturer at Madison, and he derived some income from the sale
of his textbooks in mathematics, which he revised from time to time to
bring them in touch with changing educational methods.

He had given as his reason for resigning a wish to secure leisure for
writing, and he was known to suffer severely at times from the wounds
that had driven him from active naval service. But those who knew him
best imagined that he bore in his breast deeper wounds than those of