to reach the forty-mile height at ten, the hour
when, by its computed orbit, the second satellite should be passing
overhead. "--26--27--28--" Hackett muttered the altimeter figures to
himself as the needle crept over them.

Glancing obliquely down through the window he saw that Earth was now a
huge gray ball beneath them, white cloud-oceans obscuring the drab
details of its surface here and there. "--31--32--" The plane was
climbing more slowly, and at a lesser angle. Even the X-type had to
struggle to rise in the attenuated air now about them. Only the
super-light, super-powered plane could ever have reached the terrific
height.

It was at the thirty-four mile level that the real battle for altitude
began. Norman kept the plane curving steadily upward, handling it with
surpassing skill in the rarefied air. Frost was on its windows now
despite the heating mechanism. Slowly the altimeter needle crept to
the forty mark. Norman kept the ship circling, its wings tilted
slightly, but not climbing, Earth a great gray misty ball beneath.

"Can't keep this height long," he jerked. "If our second satellite
doesn't show up in minutes we've had a trip for nothing."

"All seems mighty different up here," was Hackett's shouted comment.
"Easy enough to talk down there about hopping onto the thing, but up
here--hell, there's nothing but air and mighty little of that!"

Norman grinned. "There'll be more. If I'm right about this thing we
won't need to hop it--its own atmosphere will pick us up."

Both looked anxious as the motor sputtered briefly. But in a moment it
was again roaring steadily. Norman shook his head.

"Maybe a fool's errand after all. No--I'm still sure we're right! But
it seems that we don't prove it this time."

"Going down?" asked Hackett.

"We'll have to, in minutes. Even with its own air-feed the motor can't
stand this height for--"

* * * * *

Norman never finished the words. There was a sound, a keen rising,
rushing sound of immense power that reached their ears over the
motor's roar. Then in an instant the universe seemed to go mad about
them: they saw the gray ball of Earth and the sun above skyrocketing
around them as the plane whirled madly.

The rushing sound was in that moment thunderous, terrible, and as
winds smashed and rocked the plane like giant hands, Hackett glimpsed
another sphere that was not the sphere of Earth, a greenish globe that
expanded with lig