Just then came a rush of icy air, and Bruno pantingly cried:

"I'm swelling up--like Aesop's--bullfrog!"



CHAPTER IV.
THE PROFESSOR'S LITTLE EXPERIMENT.

Again those involuntary riders of the tornado were tossed
violently to and fro in their seemingly frail ship, while the
balloon itself appeared threatened with instant dissolution,
those eddying currents growing broken and far less regular in
action, while the fierce tumult grew in sound and volume a
thousandfold.

All around the air-ship now showed ugly debris, limbs and boughs
and even whole trunks of giant trees being whirled upward and
outward, each moment menacing the vessel with total destruction,
yet as frequently vanishing without infringing seriously upon
their curious prison.

Sand and dirt and fragments of shattered rock whistled by in an
apparently unending shower, only with reversed motion, flying
upward in place of shooting downward to earth itself.

Speech was utterly impossible under the circumstances, and the
fate-tossed voyagers could only cling fast to the hand-rail, and
hold those precious air-tubes in readiness for the worst.