speed meter of the ship began to show a lower
reading.

"Locate us on the map, Carnes!" snapped Dr. Bird.

Operative Carnes of the United States Secret Service bent over a
large-scale map of Maryland, spread open on a table. With the aid of
the navigating officer, he spotted on the map the point over which the
plane was flying.

"There goes Burleigh's ship!" cried the executive officer.

There was a gasp from the occupants of the flagplane's cabin. Far
below them, one of the crippled planes had slowed down until it had
lost flying speed. Whirling like a leaf, it plunged toward the ground.
Two small specks detached themselves from the falling mass. They
hovered over the falling plane for an instant. Suddenly a patch of
white appeared in the air, and then another. The two specks fell more
slowly.

"Good work!" exclaimed General Merton. "They took to their 'chutes
just in time."

"We'll be taking them in a few minutes if our motors don't pick up!"
replied the executive officer.

Far below them, the doomed plane crashed to the ground. As it struck
there was a blinding flash followed by vivid flames as the gasoline
from the bursted tank ignited. The two members of the crew were
drifting to the east as they fell. It was evident that they were in no
danger.

"Where is Lightwood's plane?" asked General Merton anxiously.

"It's still aloft and making its way slowly north. He intends to try
for an emergency landing at the Aberdeen Proving Ground field,"
replied the executive officer.

"That's where we had better head for," said Dr. Bird. "I hope that the
charge on Captain Lightwood's plane discharges through the tail skid
when he lands. If it doesn't, he'll be in serious danger. Follow him
and we'll watch."

* * * * *

Five thousand feet below them, the crippled plane limped slowly along
toward Aberdeen. It was gradually losing elevation. Two specks
suddenly appeared in the air, followed by white patches as the
parachutes opened. Captain Lightwood and his gunner had given up the
unequal fight and taken to the air. As the ship struck the ground,
again there was a blinding flash, followed by an inferno of roaring
flames.

"We're not in much better shape than they were, General," said the
executive officer as he came back from the control room where the
pilots were heroically striving to keep their motors turning over fast
enough to keep up flying speed. "We'd better get into our 'ch