y boy, and the first time we feared for you was yesterday
when the drug of the Zar's physician stole away your sense of right and
wrong. But we were in time to save you, and now we are ready to kneel at
your feet and proclaim you our king. First there is the Zar to be dealt
with and then we shall set up the new regime. Are you with us?"

* * * * *

Karl gazed at the speaker in wonder. He a king? Always to live amongst
the wearers of the purple? To be responsible for the welfare of half the
world? It was unthinkable! But Zar Boris, the murderer of his own
father--he must be punished, and at the hands of the son!

"I'll do it," he said simply. "That is, I'll do whatever you have
planned in the way of exterminating the Zar. Then we'll talk of the new
empire. But how is the Zar to be overcome? I thought he was invincible,
with his Moon men and terrible weapons."

"Ah! That, my boy, is where our scientists have triumphed. True, his
rays were terrible. They could not be combatted when he first returned.
The strange chemicals and gases of the Moon men defied analysis or
duplication. His citadel atop the city of Dorn is proof against them
all; proof against explosives and rays of all kinds known to him. The
disintegration and decomposition rays have no effect on the crystal of
its walls. It is hermetically sealed from the outer air so can not be
gassed. The vibration impulses have no effect upon its reinforced
structure. But there is a ray, a powerful destructive agent, against
which it is not proof. And our scientists have developed this agency.
You shall have the privilege of pressing the release of the energy that
destroys the arch-fiend in his lair. His dominance over, the empire will
fall. We shall take it--for you."

A strange exaltation shone from the faces of those in the room, and Karl
found that it was contagious. His bosom swelled and he itched to handle
the controls of this wonderful ray.

"This ray," continued the brother of old Rudolph, "carries the longest
vibrations ever measured, the vibrations of infra-red, the heat-ray. We
have succeeded in concentrating a terrific amount of power in its
production, and with it are able to produce temperatures in excess of
that of the interior of the earth, where all substances are molten or
gaseous. The Zar's crystal palace cannot withstand it for a second. He
cannot escape!"

"How'll you know he's there at the time?" Karl was greatly ex