came its roar of "_A-a-gh-rasp!_" and it leaped forward a single pace,
arms upraised. Van Manderpootz withdrew the card, and again the thing
relapsed stolidly into its place.

"What the devil!" I exclaimed. "What's it for?"

"Does van Manderpootz ever do work without reason back of it? I use it
as a demonstration in my seminar."

"To demonstrate what?"

"The power of reason," said van Manderpootz solemnly.

"How? And why ought it to work on gasoline instead of electric power?"

"One question at a time, Dixon. You have missed the grandeur of van
Manderpootz's concept. See here, this creature, imperfect as it is,
represents the predatory machine. It is the mechanical parallel of the
tiger, lurking in its jungle to leap on living prey. _This_ monster's
jungle is the city; its prey is the unwary machine that follows the
trails called streets. Understand?"

"No."

"Well, picture this automaton, not as it is, but as van Manderpootz
could make it if he wished. It lurks gigantic in the shadows of
buildings; it creeps stealthily through dark alleys; it skulks on
deserted streets, with its gasoline engine purring quietly. Then--an
unsuspecting automobile flashes its image on the screen behind its
eyes. It leaps. It seizes its prey, swinging it in steel arms to its
steel jaws. Through the metal throat of its victim crash steel teeth;
the blood of its prey--the gasoline, that is--is drained into its
stomach, or its gas-tank. With renewed strength it flings away the husk
and prowls on to seek other prey. It is the machine-carnivore, the tiger
of mechanics."

I suppose I stared dumbly. It occurred to me suddenly that the brain of
the great van Manderpootz was cracking. "What the--?" I gasped.

"That," he said blandly, "is but a concept. I have many another use for
the toy. I can prove anything with it, anything I wish."

"You can? Then prove something."

"Name your proposition, Dixon."

I hesitated, nonplussed.

"Come!" he said impatiently. "Look here; I will prove that anarchy is
the ideal government, or that Heaven and Hell are the same place, or
that--"

"Prove that!" I said. "About Heaven and Hell."

"Easily. First we will endow my robot with intelligence. I add a
mechanical memory by means of the old Cushman delayed valve; I add a
mathematical sense with any of the calculating machines; I give it a
voice and a vocabulary with the magnetic-impulse wire phonograph. Now
the point I make is this: Granted an inte