foot robot of startlingly human-like
appearance.

Lina let forth an exclamation of repugnance and fear.

"No, Mr. Shelton," Eddie objected. "The same thing will occur again.
Then there will be three."

"We'll fix that, my boy." The scientist was removing cover plates from
the hip joints of the mechanical man. "I'll disconnect the cables that
feed the locomotors. He _can't_ walk then."

Eddie was still doubtful but dared offer no further objection,
especially since Lina Shelton was watching in wide-eyed silence. He
examined the monster and saw that it was quite similar in outside
appearance to those supplied by Universal for heavy manual labor,
excepting that this one was armed as were those used for prison
guards. There were the same articulated limbs and the various clamps
and hooks for lifting and heavy hauling; the tentacles for grasping;
machine guns front and back. Under the helical headpiece that was the
antenna this robot seemed to have two eyes--a new feature--but closer
examination showed these to be the twin lenses of a stereoscopic
motion picture camera. This robot, then, could see. Or at least it
could record what the lenses saw for its masters.

"There," Shelton grunted when he had finished his tinkering, "he's
paralyzed from the waist down. Let this one try and get away from us."

"Guns aren't loaded, are they?" Eddie asked.

"Lord, no! Never have any of them loaded. That _would_ be a fool
stunt." Shelton had pulled the starting handle of a motor-generator
and its rising whine accompanied his words.

* * * * *

The vacuum tubes of the transmitter glowed into life and the scientist
manipulated the controls rapidly. Lina was watching the robot with
fascinated awe. Its arms moved in obedience to the controls, tentacles
waved and coiled; the humming of its internal mechanisms filled the
room. The locomotion controls had no effect, as the scientist had
predicted. Eddie drew a sigh of relief.

"Now, Vail, watch," Shelton exulted. "I'll show you what I was doing
with the first one." He closed a switch that lighted another bank of
vacuum tubes behind the control panel.

"You can make this one invisible?" Eddie asked incredulously.

"Certainly--from the waist up. This ought to be good."

"Mind telling me the principle?"

"Not at all--now. I've your promise of secrecy. It's a simple matter,
Vail, really. Just a problem of wave motions--light. Invisible light;
the ultr