's tested and installed, sir," was Blake's instant report. "I
think I can take it up this afternoon."

* * * * *

He left immediately to hurry to the hangar where a new plane stood
glistening in pristine freshness, and where hurrying mechanics
grumbled under their breaths at the sudden rush for a ship that was
expected to take the air a week later.

An altitude test under full load! Well, what of it? they demanded one
of another; wouldn't another day do as well as this one? And they
worked as they growled, worked with swift sureness and skill, and the
final instruments took their place in the ship that she might roll
from the hangar complete under that day's sun.

Her supercharger was tested--the adjunct to a powerful engine that
would feed the hungry cylinders with heavy air up in the heights where
the air is thin; there were oxygen flasks to keep life in the pilot in
the same thin air. And the hot southern sun made ludicrous that
afternoon the bulky, heavily-wrapped figure of Captain Blake as he
sat at the controls and listened approvingly to the roaring engine.

He waved good-by and smiled understandingly as he met the eyes of
Colonel Boynton; then pulled on his helmet, settled himself in his
seat and took off in a thunderous blast of sound to begin his long
ascent.

* * * * *

He had long since cracked open the valve of his oxygen flask when the
climb was ended, and his goggles were frosted in the arctic cold so
that it was only with difficulty he could read his instrument board.

"That's the top," he thought in that mind so light and so curiously
not his own. He throttled the engine and went into a long spiral that
was to end within a rod of where he had started on the brown sun-baked
field. The last rays of the sun were slanting over distant mountains
as he climbed stiffly from the machine.

"Better than fifty thousand," exulted Colonel Boynton. "Of course your
barograph will have to be calibrated and verified, but it looks like a
record, Blake--and you had a full load.

"Ready to go up and give merry hell to that other ship if she shows
up?" he asked. But Captain Blake shook a dubious head.

"Fifty thousand is just a start for that bird," he said. "You didn't
see them shoot out of sight, Colonel. Lord knows when they quit
_their_ climb--or where."

"Well, we'll just have a squadron ready in any event," the colonel
assured him. "We will m