f 'em," suggested Ned.

"Part of the writing is in German," Tom said, as he looked over the
mass. "I don't believe it would be worth while to try it. Still, I
can save it. Here, I'll sweep the stuff into a box, and if we get a
chance we can try to patch it together," and finding a broken box in
what had been the factory office the young inventor managed to get into
it the charred remains of the papers.

A further search failed to reveal anything that would be useful in the
way of evidence to determine what object the three men could have had
in hiding in the ruins, and Tom and Ned returned to the tank.

"What do you think about them, Tom?" asked Ned, as they were about to
start off once more for the cross-country test.

"Well, it seems like a silly thing to say--as if I imagined my tank was
all there was in this part of the country to make trouble--but I
believe those men had some connection with Simpson and with that spy
Schwen!"

"I agree with you!" exclaimed Ned. "And I think if we could get head or
tail of those burned papers we'd find that there was some
correspondence there between the man I saw up the tree and the workman
you had arrested."

"Too bad we weren't a bit quicker," commented Tom. "They must have been
in the factory when we charged it--probably came there to be in
seclusion while they talked, plotted and planned. They must have been
afraid to go out when the tank was walking through the walls."

"I guess that's it," agreed Ned. "Did you recognize any of the men,
Tom?"

"No, I didn't see 'em as soon as you did, and when they were running
they had their backs toward me. Was Simpson one?"

"I can't be sure. If one was, I guess he'll think we are keeping pretty
closely after him, and he may give this part of the country a wide
berth."

"I hope he does," returned Tom. "Do you know, Ned, I have an idea that
these fellows--Schwen Simpson, and those back of them, including
Blakeson--are trying to get hold of the secret of my tank for the
Germans."

"I shouldn't be surprised. But you've got it finished now, haven't you?
They can't get your patents away from you."

"No, it isn't that," said Tom. "There are certain secrets about the
mechanism of the tank--the way I've increased the speed and power, the
use of the spanners, and things like that--which would be useful for
the Germans to know. I wouldn't want them to find out these secrets,
and they could do that if they were in the tank a while,