inventor dryly. "That one, Feldman, is one of
my workmen. He had charge of a drop-forge press and trip-hammer that--"

"Spare me the details, Tom!" interrupted Mary. "You know I don't
understand a thing about machinery. The wireless you erected on
Earthquake Island was as much as I could comprehend."

"Well, a trip-hammer isn't as complicated as that," spoke Tom, with a
laugh, as he noticed that the two men were far enough away so they
could not hear him. "What I was going to say was, that one of those men
works in our shops. The other I don't know, but I agree with you that
he does look like a Frenchman, and old Eradicate had a meeting with a
man whom he described as being of that nationality."

"And you say they are not friends of yours?"

"I have no reason to believe they are."

"Then they must be enemies!" exclaimed Mary with quick intuition. "Oh,
Tom, you will be careful, won't you?"

"Of course I will, little girl," he said, a note of fondness creeping
into his voice, as he covered the small hand with his own large one.
"But there is no danger."

"Then why were these men discussing you?"

"I don't know that they were, Mary."

"They mentioned your name."

"Well, that may be. Probably one of them, Feldman, who works for me,
was speaking to his companion about the chance for a position. My
father and I employ a number of men, you know."

"Well, I suppose it is all right, Tom, and I surely hope it is. But
you will be careful, won't you? And you look more worried than you
used to. Has anything gone wrong?"

"Not a thing, little girl. Everything is going fine. My new aerial
warship will soon make a trial flight, and I'd be pleased to have you
as a passenger."

"Would you really, Tom?"

"Of course. Consider that you have the first invitation."

"That's awfully nice of you. But you do look worried, Tom. Has anything
troubled you?"

"No, not much. Everything is going all right now. We did have a little
trouble at a fire in one of my buildings--"

"A fire! Oh, Tom! You never told me!"

"Well, it didn't amount to much--the only suspicious fact about it was
that it seemed to have been of incendiary origin."

Mary seemed much alarmed, and again begged Tom to be on his guard,
which he promised to do. Had Mary known the warnings uttered by
Lieutenant Marbury she might have had more occasion for worry.

"Do you suppose that hammer man of yours came to these woods to meet
that Frenchman and talk about y