e long seconds as
Russ watched, frozen in fascination.

He saw it strike the hazy glow that defined the limits of the field, saw
it floating down, as if its speed had been slowed by some dense medium.

In the instant that hazy glow intensified a thousand times--became a
blinding sun-burst! Russ ducked his head, shielded his eyes from the
terrible blast of light. A rending, shuddering thud seemed to echo ...
in space rather than in air ... and both field and wrench were gone!

A moment passed, then another, and there was the heavy, solid clanging
thud of something striking metal. This time the thud was not in space,
but a commonplace noise, as if someone had dropped a tool on the floor
above.

Russ turned around and stared at Wilson. Wilson stared back, his mouth
hanging open, the smoldering, cigarette dangling from his mouth.

"Greg!" Russ shouted, his cry shattering the silence in the laboratory.

A door burst open and Manning stepped into the main laboratory room, a
calculation pad in one hand, a pencil in the other.

"What's the matter?" he demanded.

"We have to find my wrench!"

"Your wrench?" Greg was puzzled. "Can't you get another?"

"I dropped it into the field. Its time-dimension was reduced to zero. It
became an 'instantaneous wrench'."

"Nothing new in that," said Greg, unruffled.

"But there is," persisted Russ. "The field collapsed, you see. Maybe the
wrench was too big for it to handle. And when the field collapsed the
wrench gained a new time-dimension. I heard it. We have to find it."

The three of them pounded up the stairs to the room where Russ had heard
the thump. There was nothing on the floor. They searched the room from
end to end, then the other rooms. There was no wrench.

At the end of an hour Greg went back to the main laboratory, brought
back a portable fluoroscope.

"Maybe this will do the trick," he announced bleakly.

* * * * *

It did. They found the wrench _inside the space between the walls_!

Russ stared at the shadow in the fluoroscope plate. Undeniably it was
the shadow of the wrench.

"Fourth dimension," he said. "Transported in time."

The muscles in Greg's cheeks were tensed, that old flame of excitement
burning in his eyes, but otherwise his face was the mask of old, the
calm, almost terrible mask that had faced a thousand dangers.

"Power and time," he corrected.

"If we can control it," said Russ.

"Don't worry. We can