kly repaired and set again. That must be the invisible man's
reasoning.

Again Chris groaned. He moved an arm weakly and whispered:

"Can't speak much. Come closer."

The service repeater was very close now to his right hand. And he felt
a thrill when he saw the automatic come forward through the air,
descend, and pause right next to his head. He sensed a man close
behind him, and he heard:

"Well? Tell me, quick. Did you throw it over, or--?"

"Don't shoot!" Chris groaned. "I'll tell you. I didn't--throw it over.
I took it apart to get the secret of it. I put it--there."

He pointed feebly with his right hand, thus leading the invisible man
to turn his head. His legs braced imperceptibly. And then:

"Like hell!" roared Chris Travers, and shot his whole weight
backwards, grasping the service gun, whipping it around and yanking
the trigger three times at the same instant.

Shooting at nothing! But, even above the bunched roar of the
explosions, there pierced out a howl of agony that died quickly to a
sobbing moan. Chris saw the automatic drop to the floor, felt the
invisible body he had crashed into jerk away. He jumped to his feet,
clutched at that body, and caught thin air. He swung around,
listening, the service repeater in his hand.

Out of the air somewhere before him there came the sound of low,
racking gasps, and also the slow noise of feet dragging heavily
towards the cubby's door, towards the ladder that led up to the
fore-and-aft cat-walk.

Chris sprang, slashing the butt of the gun downwards. The lead was
false. He hurtled jarringly into the door jamb, the gun thumping
against the floor. The wind was knocked from him; the nausea of his
wound swept him again with a surge of dizziness. But the painful
scuffle of unseen feet ahead pulled him up once more; like a
punch-drunk fighter he staggered out from the cubby to the ladder and
hauled himself up the steps. He half-fell at the top, but his mind was
clearing; and as he swayed there he knew what he had to do--saw the
duty that lay before him....

More slowly, he crawled after the dragging footsteps and the gasps of
the invisible raider, following them through the vast dimness of the
interior of the dirigible ZX-1.

* * * * *

The chief operator on duty in the flagship of the Black Fleet swung
round in his seat and yelled through into the bridge of the massive
battleship:

"Urgent, sir! From the ZX-1!"

A moment