Before either brother could ask a question, or even give a guess
at his purpose, Professor Phaeton flung hook and cork into those
circling currents, only to have the whole jerked violently out of
his grip, the line flying upward, to vanish from the sight of
all.

That jerk was powerful enough to cut through the skin of his
hand, but the professor chuckled like one delighted, as he sucked
away the few drops of blood before adding:

"I knew it! It CAN be done, and if the worst should come to
pass, why should it not be done?"

Before an answer could be vouchsafed by either of the brothers,
the pall swooped down upon them once more, and again the supply
of natural air was shut off, while their vessel was rocked and
swayed crazily, just as though the delayed end was at last upon
them.

For several minutes this torture endured, each second of which
appeared to be an hour to those imperilled beings, who surely
must have perished, as they lay pinned fast to the floor of the
aerostat by that pitiless weight, only for the precious air-tubes
in connection with that cylinder of compressed air.

After a seeming age of torment the awful pressure was relaxed,
leaving the trio gasping and shivering, as they lay side by side,
barely conscious that life lingered, for the moment unable to
lift hand or head to aid either self or another.