The government official inquired of those in charge of the factory and explained, "That is the section of great heat. Various processes require huge temperatures which life cannot bear, and they must all be handled indirectly."
He led the way to a partition from which heat could be felt to radiate and indicated a small round area of transparent material. It was one of a row of such, through which the foggy red light of lines of glowing forges could be made out through the soupy atmosphere.
ZZ One fastened a look of suspicion on the Jovian and clicked out, "Would it be all right if I went in and looked around? I am very interested in this."
Three said, "You're being childish, One. They're telling the truth. Oh well, nose around if you must. But don't take too long; we've got to move on."
The Jovian said, "You have no understanding of the heat involved. You will die."
"Oh no," explained One casually. "Heat doesn't bother us."
There was a Jovian conference, and then a scene of scurrying confusion as the life of the factory was geared to this unusual emergency. Screens of heat-absorbent material were set up, and then a door dropped open, a door that had never before budged while the forges were working. ZZ One entered and the door closed behind him. Jovian officials crowded to the transparent areas to watch.
ZZ One walked to the nearest forge and tapped the outside. Since he was too short to see into it comfortably, he tipped the forge until the molten metal licked at the lip of the container. He peered at it curiously, then dipped his hand in and stirred it awhile to test the consistency. Having done this, he withdrew his hand, shook off some of the fiery metallic droplets and wiped the rest on one of his six thighs. Slowly he went down the line of forges, then signified his desire to leave.
The Jovians retired to a great distance when he came out of the door and played a stream of ammonia on him, which hissed, bubbled and steamed until he was brought to bearable temperature once more.
ZZ One ignored the ammonia shower and said, "They were telling the truth. No force fields."
Three began, "You see-" but One interrupted impatiently, "But there's no use delaying. The human masters instructed us to find out everything and that's that."
He turned to the Jovian and clicked out, without the slightest hesitation, "Listen, has Jovian science developed force fields?"
Bluntness was, of course, one of the natural consequences of One's less well developed mental powers. Two and Three knew that, so they refrained from expressing disapproval of the remark.
The Jovian official relaxed slowly from his strangely stiffened attitude, which had somehow given the impression that he had been staring stupidly at One's hand-the one he had dipped into the molten metal. The Jovian said slowly, "Force fields? That, then, is your main object of curiosity?"
"Yes," said One with emphasis.
There was a sudden and patent gain in confidence on the Jovian's part, for the clicking grew sharper. "Then come, vermin!"
Whereupon Three said to Two, "We're vermin again, I see, which sounds as if there's bad news ahead." And Two gloomily agreed.
It was to the very edge of the city that they were now led- to the portion which on Earth would have been termed the suburbs- and into one of a series of closely integrated structures, which might have corresponded vaguely to a terrestrial university.
There were no explanations, however, and none was asked for. The Jovian official led the way rapidly, and the robots followed with the grim conviction that the worst was just about to happen.
It was ZZ One who stopped before an opened wall section after the rest had passed on. "What's this?" he wanted to know.
The room was equipped with narrow, low benches, along which Jovians manipulated rows of strange devices, of which strong, inch-long electromagnets formed the principal feature.
"What's this?" asked One again.
The Jovian turned back and exhibited impatience. "This is a students' biological laboratory. There's nothing there to interest you."
"But what are they doing?"
"They are studying microscopic life. Haven't you ever seen a microscope before?"
Three interrupted in explanation, "He has, but not that type. Our microscopes are meant for energy-sensitive organs and work by refraction of radiant energy. Your microscopes evidently work on a mass-expansion basis. Rather ingenious."
ZZ One said, "Would it be all right if I inspected some of your specimens?"
"Of what use will that be? You cannot use our microscopes because of your sensory limitations and it will simply force us to discard such specimens as you approach for no decent reason."
"But I don't need a microscope," explained One, with surprise. "I can easily adjust myself for microscopic vision."
He strode to the nearest bench, while the students in the room crowded to the corner in an attempt to avoid contamination. ZZ One shoved a microscope aside and inspected the slide carefully. He backed away, puzzled, then tried another…a third…a fourth.
He came back and addressed the Jovian. "Those are supposed to be alive, aren't they? I mean those little worm things."
The Jovian said, "Certainly."
"That's strange- when I look at them, they die!"
Three exclaimed sharply and said to his two companions, "We've forgotten our gamma-ray radiation. Let's get out of here, One, or we'll kill every bit of microscopic life in the room."
He turned to the Jovian, "I'm afraid that our presence is fatal to weaker forms of life. We had better leave. We hope the specimens are not too difficult to replace. And, while we're about it, you had better not stay too near us, or our radiation may affect you adversely. You feel all right so far, don't you?" he asked.
The Jovian led the way onward in proud silence, but it was to be noticed that thereafter he doubled the distance he had hitherto kept between himself and them.
Nothing more was said until the robots found themselves in a vast room. In the very center of it huge ingots of metal rested unsupported in mid-air-or, rather, supported by nothing visible-against mighty Jovian gravity.
The Jovian clicked, "There is your force field in ultimate form, as recently perfected. Within that bubble is a vacuum, so that it is supporting the full weight of our atmosphere plus an amount of metal equivalent to two large spaceships. What do you say to that?"
"That space travel now becomes a possibility for you," said Three. "Definitely. No metal or plastic has the strength to hold our atmosphere against a vacuum, but a force field can- and a force-field bubble will be our spaceship. Within the year we will be turning them out by the hundreds of thousands. Then we will swarm down upon Ganymede to destroy the verminous so-called intelligences that attempt to dispute our dominion of the universe."
"The human beings of Ganymede have never attempted-" began Three, in mild expostulation.
"Silence!" snapped the Jovian. "Return now and tell them what you've seen. Their own feeble force fields- such as the one your ship is equipped with- will not stand against us, for our smallest ship will be a hundred times the size and power of yours."
Three said, "Then there's nothing more to do and we will return, as you say, with the information. If you could lead us back to our ship, we'll say good-by. But by the way, just as a matter for the record, there's something you don't understand. The humans of Ganymede have force fields, of course, but our particular ship isn't equipped with one. We don't need any."
The robot turned away and motioned his companions to follow. For a moment they did not speak, then ZZ One muttered dejectedly, "Can't we try to destroy this place?"
"It won't help," said Three. "They'd get us by weight of numbers. It's no use. In an earthly decade the human masters will be finished. It is impossible to stand against Jupiter. There's just too much of it. As long as Jovians were tied to the surface, the humans were safe. But now that they have force fields. All we can do is to bring the news. By the preparation of hiding places, some few may survive for a short while."