int of contact, when the signal reached
them. At high altitudes, planes crossing the Atlantic turned back and
returned at top speed, dropping their passengers as soon as over land.
That Moyen made no move to prevent the return of flyers out over the
ocean, and now coming back, was an ominous circumstance.

It seemed to show that he held the American flyers, all of them, in
utter contempt.

* * * * *

Prester Kleig regarded the time. It had been half an hour since Moyen
had spoken of attack, half an hour since the monsters of the deep had
started the inexorable move toward land. On the screen the submarines
were bulking larger and larger as the moments fled, until it seemed to
the Secret Agents that the great composite shadow of them already was
sweeping inland from the coast.

As the coast came close ahead of the monster subs the little aero-subs,
to the surprise of the Secret Agents, all vanished into their respective
mother ships.

"But they have to use them," groaned Munson. "For their submarines are
useless in frontal attack against our shores!"

"I am not so sure of that," said Prester Kleig. "For I have a suspicion
that those submarines have tractors under their keels, and that they can
come out on land! If this is so the monsters can, guarded by
armour-plate, penetrate to the very heart of our most populated areas
before their aero-subs are released."

None of the Secret Agents as yet had stopped to ponder how the monsters
had reached their positions, and why Moyen was attacking from the east,
when the Pacific side of the continents would have appeared to be the
obvious point of attack, and would have obviated the necessity of long,
secret under-sea journeys wherein discovery prematurely must have been
one of the many worries of the submarine commanders.

The mere fact of the presence of the monsters was enough. What had
preceded their presence was unimportant, save that their presence, and
their near approach to the shore undetected, further proved the
executive and planning genius of Moyen.

Two miles, on an average, off the eastern coast the submarines laid
their eggs--the aero-subs, which darted from the sides of the mother
ships in flights and squadrons, made the surface, and leaped into the
sky.

Five minutes later and the signal went forth to the phalanx of the
volunteers.

"Take off! Fly east and engage the enemy, and hold him in check, and the
God of our fath