I'm with you," gasped Hargreaves. "I'm not a military man, but I've
got fighting blood, and I come of a fighting race."

Dick leaped and once more swung the iron bar. The nearer of the two
mechanics went down like lead, the second, seeing his companion
bludgeoned out of the air, turned and ran.

Dick shouted, pointing. Fredegonde jumped into the plane, and the
President scrambled in behind her. The group, dismayed by the black
beam, which Luke Evans was now turning steadily upon them, had halted
irresolutely. But suddenly a head appeared, moving swiftly through the
air toward the plane. It was Von Kettler, with hood flung back, the
face distorted with rage and fury.

At his yells, the whole crowd started forward. Dick leaped into the
central cockpit, swung the helicopter lever. Something spitted past
his face, and a long streak appeared on the turret, where the
gas-paint had been scored. But he was rising, rising into that
increasing wind....

* * * * *

He heard a yell of triumph behind him. And that yell of Von Kettler's
was his undoing. There is the telepathy between close friends, but
there is also telepathic sympathy between enemies, and in an instant
Dick understood what that shout of triumph portended.

He was rising into the line of magnetic force that would anchor his
airplane helplessly, and leave it to be jerked down and held at Von
Kettler's mercy.

He released the helicopter lever and opened throttle wide. For an
instant the heavy plane hung dangerously at its low elevation,
threatening to nose over. Then Dick regained control, and was winging
away toward the sea, while yells of baffled fury from behind indicated
the chagrin of his enemies.

He glanced up. Thank heaven the dirigible had not approached the trap.
It was apparently circling overhead. Of course the observers had seen
nothing, had no conception that the headquarters of the Invisible
Empire lay below.

And yet it seemed to be drifting aimlessly back toward the
fleet--erratically, as if not under complete control. And Dick could
see the ships about a mile offshore, apparently drifting too. They
were moving as no American squadron ever moved since the day the first
hull was launched, for some of them, turned bow inward toward others,
seemed upon the point of collision, while others were lagging on the
edge of the formation, as if pointing for home.

Then suddenly the awful truth dawned upon Dick. The occu