utes."

"The Proving Ground is just ahead," said the doctor. "Can't we make it
by sacrificing our elevation?"

"We're trying to do that, Doctor, but we're down to four thousand now
and falling fast. Get ready to jump."

Dr. Bird buckled on the harness of the pack parachute which the
executive officer offered him. The rest of the crew had hurriedly
donned their packs and stood ready.

For another five minutes the plane struggled on. Suddenly a large flat
expanse of open ground which had been in sight for some time, seemed
to approach with uncanny rapidity.

"There's the landing field!" cried the General. "We'll make it yet!"

Lower and lower the plane sank with the landing field still too far
away for comfort. The pilot leveled off as much as he dared and drove
on. The motors were laboring and barely turning over at idling speed.
They passed the nearer edge of the field with the flagplane barely
thirty feet off the ground. In another moment the wheels touched and
the plane rolled to a halt.

"Don't get out!" cried Dr. Bird.

He looked around the cabin and picked up a coil of bare antenna wire
which hung near the radio set. He wrapped one end of the wire around
the frame of the plane. To the other end, he attached his pack 'chute.

"Open the door!" he cried.

* * * * *

As the door swung open, he threw the 'chute out toward the ground. As
it touched, there was a blinding flash, followed by a report which
shook the plane. A strong odor of garlic permeated the air.

"All right!" cried the doctor cheerfully. "All out for Aberdeen. The
danger is past."

He set the example by jumping lightly from the plane. General Merton
followed more slowly, his face white and his hands shaking.

"What was it, Doctor," he asked. "I have been flying since 1912, yet I
have never seen or heard of anything like that."

"Just a heavy charge of static electricity," replied the doctor. "That
was what magnetized your cylinder walls and your piston rings and
slowed your motors down. It was the same thing that wrecked those two
ships. Unless it leaks off, the men of some of your other ships are
due to get a nasty shock when they land to-night. I discharged the
charge we had collected through a ground wire. Here comes a car, we'll
go up to Colonel Wesley's office. Carnes, you have these maps?"

"Surely, Doctor."

"All right, let's go."

"But what about this ship, Doctor?" objected the General. "Can'