Hawks pressed a button on the desk intercom.

"Yes, sir?" replied a metallic voice.

"Have the rocket scout ready for flight in five minutes," Hawks ordered.
He snapped off the intercom without waiting for a reply and turned to
Strong. "Let's go, Steve."

The two veteran spacemen left the office without further comment and
rode down in the vacuum elevator to the highway level. Soon they were
speeding out to the spaceport in Hawks' special jet car.

At the blast-pitted field they were met by a young Solar Guard officer
and an elderly man carrying a leather case, who were introduced as
Lieutenant Claude and Professor Newton.

While Claude prepared the rocket scout for blast-off, Strong, Hawks, and
Newton discussed the possibility of lava dust having risen to great
heights from another side of the planet.

"While I'm reasonably sure," stated Newton, "that no volcano has erupted
recently here on Venus, I can't be sure until I've examined samples of
this so-called dirt."

"I'll have Lieutenant Claude contact the University of Venus," said
Hawks. "Their seismographs would pick up surface activity."

Claude stuck his head out of the hatch and reported the ship ready for
blast-off. Strong followed the professor and Hawks aboard and strapped
himself into an acceleration chair. In a moment they were blasting
through the misty atmosphere of Venus into the depths of space.

Fifteen minutes later, Hawks and Strong were standing on the hull of the
ship in space suits, watching the professor take a sample of a dirty
black cloud, so thick it was impossible to see more than three feet.
Strong called to the professor through the spacephone.

"What do you make of it, sir?" he asked.

"I wouldn't want to give you a positive opinion without chemical tests,"
answered the professor, his voice echoing in Strong's fish-bowl helmet.
"But I believe it's one of three things. One, the remains of a large
asteroid that has broken up. Two, volcanic ash, either from Venus or
from Jupiter. But if it came from Jupiter, I don't see how it could have
drifted this far without being detected on radar."

Now, holding a flask full of the black cloud, the professor started back
to the air lock.

"You said three possibilities, professor," said Strong.

"The third," replied the professor, "could be--"

The professor was interrupted by Lieutenant Claude calling over the
intercom.

"Just received a report from the University of Venus, sir!" said