ed the earth below
him for a sign of the man and girl who had been the only danger to his
plan and now were unarmed fugitives. And there were four
air-dreadnaughts in plain sight and five thousand men watching, and
Kreynborg hunted, for sport, a comrade of the five thousand men and a
woman every one of them would have risked or sacrificed his life to
protect.

He seemed certain that they were below him. Presently he dropped
another gas-bomb, and another. And then Sylva stumbled and caught at
something, and there was a crashing sound as a sapling wavered in her
grasp.... And Thorn picked her up and fled madly. But billowing white
vapor spouted upward before him. He dodged it, and the helicopter was
just overhead and more smoke spouted, and more, and more.... They were
hemmed in, and Sylva clung close to Thorn and sobbed....

* * * * *

Five thousand men, in a thousand grounded aircraft, shouted curses
that made no sound. They waved weapons that were utterly futile. They
were as impotent as so many ghosts. Their voices made not even the
half-heard whisper one may attribute to a phantom.

The fog-vapor closed over Thorn and Sylva as Kreynborg grinned
mockingly at the raging men without the dome of force. He swept the
helicopter to a position above the last view of Thorn and Sylva, and
the downward-beating screws swept away the foggy gas. Thorn and Sylva
lay motionless, though Thorn had instinctively placed himself in a
position of defense above her.

The Fighting Force of the United Nations watched, raging, while
Kreynborg descended deliberately into the area the helicopter-screws
kept clear. While he searched Thorn's pockets reflectively and found
nothing more deadly than small pebbles which might strike sparks, and
a small forked stick. While he grinned mockingly at the raging armed
men and made triumphant gesticulations before carrying Sylva's limp
figure to the helicopter. While the little ship rose and swept away
toward the rocket-plane.

It descended and was lost to view. Thorn lay motionless on the earth.
Seven-eighths of the fighting force of the United Nations was
imprisoned within the space between two domes of force no matter could
penetrate. A ring two miles across and ten miles in outer diameter
held the whole fleet of the United Nations paralyzed.

There was sheer panic through the Americas and Europe and the few
outlying possessions of the United Nations.... And it was