can be
done about it?"

Dr. White hitched his chair closer and his fingers closed with a fierce
grasp upon the other's knee. A militant boom came into his voice.

"My boy," he said, "we are to strike back. We are going to invade the
fourth-dimensional plane of these hellhounds. We are going to make them
feel our strength. We are going to strike back."

Henry Woods sprang to his feet.

"How?" he shouted. "Have you...?"

Dr. White nodded.

"I have found a way to send the third-dimensional into the fourth. Come
and I will show you."

* * * * *

The machine was huge, but it had an appearance of simple construction. A
large rectangular block of what appeared to be a strange black metal was
set on end and flanked on each side by two smaller ones. On the top of
the large block was set a half-globe of a strange substance, somewhat,
Henry thought, like frosted glass. On one side of the large cube was set
a lever, a long glass panel, two vertical tubes and three clock-face
indicators. The control board, it appeared, was relatively simple.

Beside the mass of the five rectangles, on the floor, was a large plate
of transparent substance, ground to a concave surface, through which one
could see an intricate tangle of wire mesh.

Hanging from the ceiling, directly above the one on the floor, was
another concave disk, but this one had a far more pronounced curvature.

Wires connected the two disks and each in turn was connected to the
rectangular machine.

"It is a matter of the proper utilization of two forces, electrical and
gravitational," proudly explained Dr. White. "Those two forces, properly
used, warp the third-dimensional into the fourth. A reverse process is
used to return the object to the third. The principle of the machine
is--"

The old man was about to launch into a lengthy discussion, but Henry
interrupted him. A glance at his watch had shown him press time was
drawing perilously close.

"Just a second," he said. "You propose to warp a third-dimensional being
into a fourth dimension. How can a third-dimensional thing exist there?
You said a short time ago that only a specified dimension could exist on
one single plane."

"You have missed my point," snapped Dr. White. "I am not sending a
third-dimensional thing to a fourth dimension. I am changing the
third-dimensional being into a fourth-dimensional being. I add a
dimension, and automatically the being exists on a dif