tegrates. A certain
pitch of resonance will break a pane of glass. It's a matter of
vibration, solely, wherein the molecules composing any object animate or
inanimate, are hurled in all directions instantaneously.

"Professor Maniel's apparatus, the Vibration-Retarder, is able to
recapture the vibrations, speeding outward endlessly through space, and
to reconstruct, and _draw back_ to visibility the objects destroyed by
this visible vibratory ray, whatever it is. This problem, then, falls
into the province of Professor Maniel!"

* * * * *

Through the heart and soul of Prester Kleig there suddenly flowed a
great surge of hope.

"General Munson, if you will operate the machinery of the
Vibration-Retarder, I wish to talk with Professor Maniel!"

Instantly, efficiently, without a word in reply to the eager command of
Prester Kleig, General Munson relieved Professor Maniel at the apparatus
which Maniel called the Vibration-Retarder, his invention which he had
combined with audible teleview to complete this visual miracle of the
Secret Room. Professor Maniel stepped to where Prester Kleig was
sitting.

Prester Kleig put fingers to his lips for silence, and an expression of
surprise crossed the wrinkled dead-white face of the Professor.

Before Kleig could speak, however, there came a signal from somewhere
outside the Secret Room, a signal which said that the doors were being
opened and that a personage was coming. The Secret Agents looked at one
another in surprise, for every man who had a right to be inside the
Secret Room was already present.

"I know," said Kleig, his face a mask of terror. "It is Charmion and
Carlos Kane! Moyen, the devil, has managed to make sure of obedience to
his orders!"

The Secret Agents turned back to the screen, upon which the view of the
first aerial brush of the American flyers with the minions of Moyen, in
their aero-subs, was drawing to a terrible close.

For, as the aero-sub commanders had played with the warships, which had
no human beings aboard them, so now did they play with the planes of the
Americas.

* * * * *

One American flyer, startled into a frenzy by the fate of his fellows,
put his helicopter into action, and leaped madly out of the midst of the
battle. Instantly an aero-sub zoomed, skyward after him. Again that
golden streak of light from the nose of an aero-sub, and the helicopter
vanes and the sle