oring him, cursing.

And then there came faintly to his ears the twang of a dart gun; the
shrill scream of its deadly vibrating missile; a violent blow that flung
him headlong.

* * * * *

Like a cat, he bounced to his feet, crouching with Chan Dai's dart gun
at his shoulder. A strangely grotesque heap was at his feet--Tom Fuller.
Off there in the thinning mist he saw a shadowy figure and he fired at
it twice. Whether his darts found their mark he was never to know, for a
wall of white swept down suddenly to obscure his vision. Snow! Great
massed flakes falling endlessly--the moisture of the mist crystallized
and closing in on him to hide him even more safely, than had the mists
themselves.

He was on his knees then at Fuller's side. A brilliant flash and a
screaming roar over amongst the rocks apprised him of the fact that the
guard's dart had gone wide. And yet Fuller was down, moaning with pain.
Luke tried to turn him over and found that his body had taken on
tremendous weight. He was flattened, crushed to the rocky surface of
Vulcan by the full force of its gravity!

"What the devil!" he grunted as he heaved and strained. "What'd they do
to you, old man?"

With great effort he succeeded in turning the scientist face up. Then he
saw what had happened, and knew in a flash that Fuller had saved him
from the singing dart whose energy was making a sizzling puddle of the
stones where it had landed. The missile, in passing, had carried away
the belt and part of the fabric of Tom's garment--carried away the
capsule and the radium that energized it. Made the thing worse than
useless. And Fuller had done this for him; he had flung himself upon
Luke to shove him out of the line of fire ... risking his own life
gladly ... lucky the deadly dart had missed his body, but....

* * * * *

"You go on, Fenton," the scientist was whispering through lips that were
blue and stiff. "Leave me here. I'm licked. But you can carry on the
work; go to my friends and tell them--everything. Tell them what you saw
back there--tell them----"

"Shut up!" Luke's words were softly growled. There was a new and utterly
unaccountable huskiness in his voice as he straddled the prone body and
locked his strong fingers underneath. "You ain't gonna be left behind,"
he grunted. "We're goin' on, brother, together."

His back straightened and Fuller was swung clear of