, and when he went to the
fair-grounds the following morning with John and actually saw what a
fine-looking ship the big craft was, he was stumped for words to
express his full admiration.

Then while John and Tom went industriously to work, Paul and Bob rode
away to Clark Polytechnic in New York with Mr. Giddings. Just before
starting into the city that morning, the newspaper man had met Tom, and
there was little doubt that he was well pleased with this addition to
his force of workers. Of course Paul and Bob were sorry to have to
interrupt their labors on Sky-Bird II, but there was no help for it,
and there was some consolation in the thought that undoubtedly their
instructors would let them work on some of the airplane's smaller parts
as a portion of their school mechanical practice. This supposition
indeed proved correct, and as the fall days passed they found the two
student chums not only partaking with full spirit in the sports of
their comrades, but also contributing in no small measure to the
progress of the work on the new airplane.

As a rule, Paul and Bob managed to stop in each Saturday for at least
an hour or so to lend some assistance to John and Tom, and when there
were no school contests on, they spent practically the entire holiday
in the hangar.

The cool days of November soon compelled the boys to install a couple
of heating stoves in the big building, and after that the place was
warm and cheery throughout the working day, no matter how blustery and
nippy the weather. At night the coals were carefully banked with
ashes, to keep up a fair degree of warmth until the following morning.

Up to this time nothing had been seen of any suspicious person lurking
around the premises, but one afternoon late in the month, when Tom
Meeks was working alone in the hangar and John had gone to town after
some bolts, Tom thought he heard a strange sound at one of the two
windows near the workbench.

Turning quickly from the wing-strut which he had been setting in place,
Tom faced the window just in time to see a swarthy-looking countenance,
adorned with a toothbrush-like mustache, pulled out of range. The
mechanic had been informed of Bob's experience with the man who had
evidently followed him to the grounds during the summer, also of the
blue-prints which had been stolen, and now as he observed the
similarity in looks between this eavesdropper and the reported shadow
of Bob, he became quite excited.

W