e inquiries of persons living along the way, though once or
twice Tom did get out to ask, confirming the fact that the big machine
had rumbled past in a direction away from the Swift home.

"I had an idea they might have doubled on their tracks for a time, and
backed her up just to fool us," Tom said. "They might do that, keeping
her in the same tracks."

But this, evidently, had not been done, and the tank was making good
speed away from the Swift house. They kept up the search until about
midnight, and then a heavy rain began just before they reached a point
where several roads branched.

"Luck's with them!" exclaimed Tom. "This will wash away the marks, and
we'll have to go it blind. Might as well put up here for the night," he
added, as they came to a village hotel.

It was evident that little more could be done in the rain and darkness,
and there was danger of over-running the trail of the tank if they kept
on. So they turned in at the hotel and got what little rest they could
in their anxious state of minds.

Tom tried to be cheerful and to look for the best, but it was hard
work. The tank was his pet invention, and, moreover, that her secrets
should fall into the hands of the enemy and be used for Germany and
against the United States eventually, made the young inventor feel that
everything was going wrong.

The rain kept up all night, and this would make it correspondingly hard
for them to pick up the trail in the morning.

"The only thing we can do is to make inquiries," decided Tom.
"Fortunately, the tank can't easily be hidden."

They started off after an early breakfast. The roads were so muddy and
wet that traveling was difficult and dangerous for the automobile, and
they were disappointed in finding no one who had seen or heard the tank
pass up to a point not far from the hotel where they had stayed
overnight. From then on the big machine seemed to have disappeared.

"I know what they've done," Tom said, when noon came and they had found
no trace of the ponderous war machine. "They've left the road and
taken her cross country, and we can't find the spot where they did this
because the rain has washed out the marks. Well, there's only one thing
left to do."

"What's that?" asked Ned.

"Get the Hawk! In that we can look down and over a big extent of
country. That's what I'll do--I'll phone for the airship. The rain is
stopping, I think."

The rain did cease by the time one of Tom's men brough