n we have, but an emotion that we'd expect a
creature made of energy to have. An emotion of frustration! It
had me cornered. I escaped. The energy sphere met resistance.
When energy meets resistance it changes!"

"I don't get it."

"Look, Masters. If the spheres are mixtures of energies, like we
are mixtures of chemicals, death means extinction, just as
biological death means the extinction of the chemical action in
our lives. Theologians say we don't die--that there's a change
and we go on existing in a spiritual life. Now let's take a peep
at what science tells us about energy: Newton says energy is
never extinguished. When it ceases in one form, it changes to
another. What happens when you run electricity through a
resistance coil?"

"It turns to heat, of course!"

"And when you enclose light where it can't escape?"

"It turns to heat!" Masters' face brightened. "And if you pen up
heat, it turns to light. I learned that in school. Resistance
causes a change. But what do the spheres turn to?"

"Radio energy, Masters! Something absolutely harmless to man.
These living, energy spheres will change to radio energy when
they meet resistance. Frustration is resistance. Frustration is
an emotion. An overwhelming emotion for the spheres! The sphere
is frustrated--meets resistance--it disappears. In other words,
it dies!"

* * * * *

From the city came screams and cries. The spheres had attacked at
last.

The men in the wooded field could see the darting balls sending
their searing bolts down on the heads of hapless victims. The
crashing roar of the slaughter sounded like distant thunderstorms.

Streets were jammed with panic-stricken human beings, fleeing
from the unknown menace which slashed with bolts of heat energy.

From the hole in the factory roof poured more spheres to join the
destruction.

"They breed fast, the devils!" said Masters.

A figure in khaki approached Taylor. It was Pember with blood
running from a cut on the side of his head. He saluted briskly.

"Norden escaped, sir!" he blurted. "The dirty so-and-so cracked
me over the head with the trench tool and got away!"

"I never thought he'd turn yellow," Masters said. "Well, maybe
it's a good thing he's gone. I never trusted him anyhow."

"Which way did he go?" Taylor asked.

"He went toward the factory, sir!" Pember replied. "He didn't
knock me out. Just a glancing blow. I was too dazed to stop him,
but I