d their annihilating force, another sagged and fell.
From the remaining three invisible force-shells flicked around them,
but in an instant Sarja had whirled the boat through them and down
into the water-tunnel!

Norman clung desperately to his seat as the boat flashed down through
the waters, and then, as Sarja sent it flying out through the great
tunnel's waters, glimpsed, close behind, the beams of the three Rala
boats as they pursued them through the tunnel, overtaking them. Could
the force-shells be fired under water? Norman did not know, but
desperately he swung the force-gun back as they rushed through the
waters, and pressed the catch. An instant later beams and boats behind
them in the tunnel vanished.

His lungs were afire; it seemed that he must open them to the
strangling water. The boat was ripping the waters at such tremendous
speed that he felt himself being torn from his hold on it. Pain seemed
poured like molten metal through his chest--he could hold out no
longer; and then the boat stabbed up from the waters into clear air!

* * * * *

Norman panted, sobbed. Behind them rose the colossal metal dome of the
frog-city, gleaming dully in the silvery light that flooded the
far-stretching seas. That light poured down from a stupendous silver
crescent in the night skies. Norman saw dully the dark outlines on it
before he remembered. Earth! He laughed a little hysterically. Sarja
was driving the flying-boat out over the sea and away from the
frog-city at enormous speed. At last he glanced back. Far behind them
lay the great dome and up around it gleaming lights were pouring,
lights of pursuing Rala boats.

"We escape," Sarja cried, "the city of the Ralas, from which none ever
before escaped!"

Remembrance smote Norman. "Hackett! Held off those frog-men so we
could get away--we'll come back for him, by God!"

"We come back!" said Sarja. "We come back with all the green men of
this world to the Ralas' city, yes! I know what Fallas has planned."

"Can you find your way to him--to your city?" Norman asked.

Sarja nodded, looking upward. "Before the next sun has come and gone
we can reach it."

The boat flew onward, and the great dome and the searching lights
around it dropped beneath the horizon. Norman felt the warm wind
drying his drenched garments as they rushed onward. Crouched on the
boat he gazed up toward the silver crescent of Earth sinking toward
the horizon ahe