tion of our hero, donned a heavy coat.

"For it's cold in the upper regions," said Tom.

Several servants in the physician's household had gathered to see him
depart in this novel fashion, and the chauffeur of the auto, in which
the specialist usually made his calls, was also there.

"I'll give you a hand," said the chauffeur to the young inventor. "I
was at an aviation meet once, and I know how it's done."

"Good," exclaimed Tom. "Then you can hold the machine, and shove when I
give the word."

Tom started the propeller himself, and quickly jumped into his seat.
The chauffeur held back the Humming-Bird until the young aviator had
speeded up the motor.

"Let go!" cried the youthful inventor, and the man gave the little
craft a shove. Across the rather uneven ground of the doctor's yard it
ran, straight for a big iron barrier.

"Look out! We'll be into the fence!" shouted the surgeon. "We'll be
killed!" He seemed about to leap off.

"Sit still!" cried Tom, and at that instant he tilted the elevation
planes, and the craft shot upward, going over the fence like a circus
horse taking a seven-barred gate.

"Oh!" exclaimed the physician in a curious voice. They were off on
their trip to save the life of Mr. Swift.

What the sensations of the celebrated specialist were, Tom never
learned. If he was afraid, his fright quickly gave place to wonder, and
the wonder soon changed to delight as the machine rose higher and
higher, acquired more speed, and soared in the air over the country
that spread out in all directions from Kirkville.

"Magnificent! Magnificent!" murmured the doctor, and then Tom knew that
the surgeon was in the grip of the air, and was one of the "bird-men."

Every moment the Humming-Bird increased her speed. They passed over the
river near where men were working on the broken bridge. It was now no
barrier to them. Tom, noting the barograph, and seeing that they were
twenty-two hundred feet high, decided to keep at about that distance
from the earth.

"How fast are we going?" cried Dr. Hendrix, into the ear of the young
inventor.

"Just a little short of a hundred an hour!" Tom shouted back. "We'll
hit a hundred and five before long."

His prediction proved true, and when about forty miles from Shopton
that terrific speed had been attained. It seemed as if they were going
to have a trip devoid of incident, and Tom was congratulating himself
on the quick time made, when he ran into a contrary st