familiar warning of
impending danger rippled across the back of his neck. And he impulsively
slid the guard off the electric firing button of his forward guns, and
got set to catch the oncoming seaplane in his sights at an instant's
alarm.

There seemed no need to be on the alert for danger, however. The figure
in the rear pit of the strange-looking seaplane stood up in the
slip-stream and waved both hands in greeting. Because of the helmet and
goggles the figure was wearing neither Dave nor Freddy could get a look
at his face. And a flying jacket covered up whatever kind of uniform he
was wearing. In short, the waving figure could well have been a
daredevil ace from Timbuktu as far as Dave Dawson and Freddy Farmer were
concerned.

"Who the heck are you?" Dave shouted just to let off steam. "Friend or
foe? And where in the world did you dig up that crate, anyway?"

Of course the thunder of the Dauntless' Cyclone drowned out Dave's
words, but a split second later it was almost as though the two unknowns
in the other plane had heard and understood. This time the figure in the
pilot's pit stood up, and waved. Then he stopped waving and pointed past
the Dauntless. Dawson frowned, then instinctively twisted around in the
pit to stare back. He saw Freddy start to twist around, and then
violently check himself as wild alarm lighted up his face.

"Dave! Look out! The blasted beggars are--!"

And that's all Dawson heard of Freddy Farmer's screaming voice, for the
rest was drowned out by the savage yammer of aerial machine guns. He
jerked front just in time to see the seaplane boring straight in at him
from the left. It was headed dead for the nose of the Dauntless, and in
the infinitesimal period of frozen astonishment Dawson saw the bullets
from the guns of the other plane hammer and chew their way through the
Cyclone's cowling. And then before he could move the control stick, or
jump on a rudder pedal, the seaplane had flashed by him, and his Cyclone
was starting to cough raspingly and spew black smoke out of its
exhaust.

"Why, you dirty, low down rat!" Dave roared, and dropped the nose of the
Dauntless. "You--you double-crossing, cheating bum! I'll teach you to
pull a dirty one like that! Come back here and take--!"

But Dawson was simply exploding words, and he ended them with a bitter
groan, as more smoke poured back from the bullet-damaged engine, and the
power plant quit altogether. He and Freddy had been tricked