scopic bit of matter. It was a cinch to get the stuff I needed."

Russ chuckled and put the machine back on the table. He gestured toward
it.

"It maintains a tiny field similar to our television field," he
explained. "But it's modified along a special derivation with a magnetic
result. It can follow and find the original mass of any metallic
substance it may contain."

"Clever," commented Greg.

Russ lit his pipe, puffed comfortably. "We needed something like that."

The red light on the board snapped on and blinked. Russ reached out and
slammed home the lever, twirled dials. It was only another passenger
ship. They relaxed, but not too much.

* * * * *

"I wonder what he's up to," said Russ.

Stutsman's car had stopped in the dock section of New York. Crumbling,
rotting piers and old tumbledown warehouses, deserted and unused since
the last ship sailed the ocean before giving way to air commerce, loomed
darkly, like grim ghosts, in the darkness.

Stutsman had gotten out of the car and said: "Wait here."

"Yes, sir," said the voice of the driver.

Stutsman strode away, down a dark street. The televisor kept pace with
him and on the screen he could be seen as a darker shape moving among
the shadows of that old, almost forgotten section of the Solar System's
greatest city.

Another shadow detached itself from the darkness of the street, shuffled
toward Stutsman.

"Sir," said a whining voice, "I haven't eaten ..."

There was a swift movement as Stutsman's stick lashed out, a thud as it
connected with the second shadow's head. The shadow crumpled on the
pavement. Stutsman strode on.

Greg sucked in his breath. "He isn't very sociable tonight."

Stutsman ducked into an alley where even deeper darkness lay. Russ, with
a delicate adjustment, slid the televisor along, closer to Stutsman,
determined not to lose sight of him for an instant.

The man suddenly turned into a doorway so black that nothing could be
seen. Sounds of sharp, impatient rappings came out of the screen as
Stutsman struck the door with his stick.

Brilliant illumination sprang out over the doorway, but Stutsman seemed
not to see it, went on knocking. The colors on the screen were
peculiarly distorted.

"Ultra-violet," grunted Greg. "Whoever he's calling on wants to have a
good look before letting anybody in."

The door creaked open and a shaft of normal light spewed out into the
street, turning its mur