laughter.
"Quick, nifty and entertaining, that! Say Engineer Fairbanks, I don't
know who that fellow Wheels is, but I'd be interested and proud to
make his acquaintance. Now steam up and air brake ready, while we pass
the crossing!"

"Passing the crossing," as Clark designated it, proved, however, to be
no difficult proceeding. The crowd of hoodlums had got a set-back from
the boy with the piston-rod arm, it seemed. They scanned Ralph and
Clark keenly as they passed by, but made no attempt to either hail or
halt them.

"We've run the gauntlet this time," remarked Clark. "Hello--four
times!"

The vigilant companion of the young engineer was glancing over his
shoulder as he made this sudden and forcible remark.

"Four times what?" inquired Ralph.

"That fireman of yours."

"Mr. Fogg?"

"Yes."

"What about him?"

"Say," replied Clark, edging close to Ralph, "just take a careless
backward look, will you? About half the square down on the opposite
side of the street you'll see Fogg."

"Why such caution and mystery?" propounded Ralph.

"I'll tell you later. See him?" inquired Clark, as Ralph followed out
the suggestion he had made.

Ralph nodded assentingly. He had made out Fogg as Clark had described.
The fireman was walking along in the direction they were proceeding.
There was something stealthy and sinister in the way in which he kept
close to the buildings lining the sidewalk.

"That's four times I've noticed Fogg in this vicinity this morning,"
reported Clark. "I discovered him opposite the lodging house when I
first came out this morning. When I came back he was skulking in an
open entry, next door. When we left the house together I saw him a
block away, standing behind a tree. Now he bobs up again."

"I can't understand his motive," said Ralph thoughtfully.

"I can," declared Clark with emphasis.

"What's your theory?"

"It's no theory at all, it's a dead certainty," insisted Clark. "Your
fireman and that gang of hoodlums hitch together in some way, you mark
my words. Well, let it slide for a bit. I'm hungry as a bear, and
here's the restaurant."

It was a neat and inviting place, and with appetizing zeal the two
boys entered and seated themselves at a table and gave their order for
wheat cakes with honey and prime country sausages. Just as the waiter
brought in the steaming meal, Clark, whose face was toward the street,
said:

"Fogg just passed by, and there goes the crowd of boys. I'm thi