ered by?" Martin asked coldly.

"Slaves," the robot said, examining the lamp. He switched it on,
blinked, and then unscrewed the bulb. "Voltage, you say?"

"Don't be a fool," Martin said. "You're overplaying your part. I've got
to get going in a minute. Do you want a jolt or don't you?"

"Well," the robot said, "I don't want to seem unsociable. This _ought_
to work." So saying, he stuck his finger in the lamp-socket. There was a
brief, crackling flash. The robot withdrew his finger.

"_F(t)_--" he said, and swayed slightly. Then his fingers came up and
sketched a smile that seemed, somehow, to express delighted surprise.

"_Fff(t)!_" he said, and went on rather thickly, "_F(t)_ integral
between plus and minus infinity ... _a-sub-n_ to _e_...."

Martin's eyes opened wide with shocked horror. Whether a doctor or a
psychiatrist should be called in was debatable, but it was perfectly
evident that this was a case for the medical profession, and the sooner
the better. Perhaps the police, too. The bit-player in the robot suit
was clearly as mad as a hatter. Martin poised indecisively, waiting for
his lunatic guest either to drop dead or spring at his throat.

The robot appeared to be smacking his lips, with faint clicking sounds.

"Why, that's wonderful," he said. "AC, too."

"Y-you're not dead?" Martin inquired shakily.

"I'm not even alive," the robot murmured. "The way you'd understand it,
that is. Ah--thanks for the jolt."

* * * * *

Martin stared at the robot with the wildest dawning of surmise.

"Why--" he gasped. "Why--_you're a robot_!"

"Certainly I'm a robot," his guest said. "What slow minds you pre-robots
had. Mine's working like lightning now." He stole a drunkard's glance at
the desk-lamp. "_F(t)_--I mean, if you counted the kappa waves of my
radio-atomic brain now, you'd be amazed how the frequency's increased."
He paused thoughtfully. "_F(t)_," he added.

Moving quite slowly, like a man under water, Martin lifted his glass and
drank whiskey. Then, cautiously, he looked up at the robot again.

"_F(t)_--" he said, paused, shuddered, and drank again. That did it.
"I'm drunk," he said with an air of shaken relief. "That must be it. I
was almost beginning to believe--"

"Oh, nobody believes I'm a robot at first," the robot said. "You'll
notice I showed up in a movie lot, where I wouldn't arouse suspicion.
I'll appear to Ivan Vasilovich in an alchemist's lab, and