Tommy frowned, then labored with the question. The bearded old man spoke gravely. At his answer, Tommy grimaced.

"Datl's gone looking for the cave their legends tell of," he said reluctantly. "He's the lad who wanted the city to gas Earth with some ghastly stuff they know of, and move over when the gas was harmless again. But the cave has been lost for centuries, and it's in the torrid zone--which _is_ torrid! We're near the North Pole of this planet, and it's tropic here. It must be mighty hot at the equator.

Datl took a ship and supplies and sailed off. He may be killed. In any case it'll be some time before he's dangerous. Meanwhile, as I said, we're marooned."

"And more," said Denham deliberately. "By the time the authorities halfway believed me, and Von Holtz could talk, there were more deaths from the Death Mist. It wiped out a village, clean. So when it was realized that I'd caused it--or that was their interpretation--and was the only man who could cause it again, why, the authorities thought it a splendid idea for me to come through the Tube. They invited me to commit suicide. My knowledge was too dangerous for a man to have. So,"

he added grimly, "I have committed suicide. We will not be welcomed back on Earth, Tommy."

Tommy made an impatient gesture.

"Worry about that later," he said impatiently. "Right now there's a war on. Rahn's desperate, and the prisoners we took this morning say Jacaro and his gunmen are there, advising them. Ragged Men have joined in to help kill civilized humans. And they've still got aircraft."

"Which can still bombard this city," observed Denham. "Can't they?"

Tommy pointed to the many-colored beams of light playing through the sky overhead.

"No. Those lights were invented to guide night-flying planes back home. They're static lights--cold lights, by the way--and they register powerfully when a static-discharge propeller comes within range of them. If Rahn tries a night attack, Aten and I take off and shoot them down again. That's that. But we've got to design gas masks for these people, and I think I can persuade the Council to send over and take all Rahn's aircraft away to-morrow. But the real emergency is the jungle."

He expounded the situation of the city as he understood it. He labored painstakingly to make his meaning clear while Denham blew meditative smoke rings and Smithers listened quietly. But when Tommy had finished, Smithers said in a vast calm:

"Say, Mr. Reames, y'know I asked you to get somebody to take me through some o' these engine rooms. That's kinda my specialty. An'

these folks are good, no question! There's engines--even steam engines--we couldn't build on Earth. But, my Gawd, they're dumb! There ain't a piece of automatic machinery on the place. There's one man to every motor, handlin' the controls or the throttle. They got stuff we couldn't come near, but they never thought of a steam governor."

Tommy turned kindling eyes upon him. "Go on!"

"h.e.l.l," said Smithers, "gimme some tools an' I'll go through one shop an' cut the workin' force in half, just slammin' governors, reducin'

valves, an' automatic cut-offs on the machines I understand!"

Tommy jumped to his feet. He paced up and down, then halted and began to spout at Aten and the Keeper of Foodstuffs. He gesticulated, fumbling for words, and hunted absurdly for the ones he wanted among his written lists, and finally was drawing excitedly on Aten's black-metal tablet. Smithers got up and looked over his shoulder.

"That ain't it, Mr. Reames," he said slowly. "Maybe I...."

Tommy pressed the stud that erased the page. Smithers took the tablet and began to draw painstakingly. Aten, watching, exclaimed suddenly.

Smithers was drawing an actual machine, actually used in the Golden City, and he was making a working sketch of a governor so that it would operate without supervision while the steam pressure continued.

Aten began to talk excitedly. The Keeper of Foodstuffs took the tablet and examined it. He looked blank, then amazed, and as the utterly foreign idea of a machine which controlled itself struck home, his hands shook and color deepened in his cheeks.

He gave an order to Aten, who dashed away. In ten minutes other men began to arrive. They bent over the drawing. Excited comments, discussions and disputes began. A dawning enthusiasm manifested itself. Two of them approached Smithers respectfully, with shining eyes. They drew their tablets from their belts, rather skilfully drew the governor he had indicated in larger scale, and by gestures asked for more detailed plans. Smithers stood up to go with them.

"You're a hero, now, Smithers," Tommy informed him exultantly.

"They'll work you to death and call you blessed!"

"Yes, sir," said Smithers. "These fellas are right good mechanics.

They just happened to miss this trick." He paused. "Uh--where's Miss Evelyn?"

"With Aten's--wife," said Tommy. This was no time to discuss the marital system of Yugna. "We were prisoners until this morning. Now we're guests of honor. Evelyn's talking to a lot of women and trying to boost our prestige."

Smithers went over to the gesticulating group of draftsmen. He settled down to explain by drawings, since he had not a word of their language. In a few minutes a group went rushing away with the sketch tablets held jealously to their b.r.e.a.s.t.s, bound for workshops. Other men appeared to present new problems. A wave of sheer enthusiasm was in being. A new idea which would lessen the demands of the machines was a G.o.dsend to these folk.

Then Denham blew a smoke ring and said meditatively:

"I think I've got something too, Tommy. Ultra-sonic vibrations. Sound waves at two to three hundred thousand per second. Air won't carry them. Liquids will. They use 'em to sterilize milk, killing the germs by sound waves carried through the fluid. I think we can start some ultra-sonic generators out there that will go through the wet soil and kill all vegetation within a given range. We might clear away the jungle for half a mile or so and then use ultra-sonic beams to help it clear while new food-plants are tried out."

Tommy's eyes glowed.

"You've given yourself a job! We'll turn this planet upside down."

"We'll have to," said Denham drily. "This city may believe in you, but there are others, and these folk are a little too clever. There's no reason why some other city shouldn't attack Earth, if they seriously attack the problem of building a Tube."

Tommy ground his teeth, frowning. Then he started up. There was a new noise down in the city. A sudden flare of intolerable illumination broke out. There was an explosion, many screams, then the yelling tumult of men in deadly battle.

Every man on the tower terrace was facing toward the noise, staring.

The white-bearded man gave an order, deliberately. Men rushed. But as they swarmed toward an exit, a green beam of light appeared near the uproar. It streaked upward, wavering from side to side and making the golden walls visible in a ghostly fashion. It shivered in a hasty rhythm.

Aten groaned, almost sobbed. There was another flash of that unbearable actinic flame. A thermit-thrower was in action. Then a third flash. This was farther away. The tumult died suddenly, but the green light-beam continued its motion.

Tommy was snapping questions. Aten spoke, and choked upon his words.

Tommy swore in a sudden raging pa.s.sion and then turned a chalky face toward the other two men from Earth.

"The prisoners!" he said in a hoa.r.s.e voice. "The men from Rahn! They broke loose. They rushed an a.r.s.enal. With hand weapons and a thermit-thrower they fought their way to a place where the big vehicles are kept. They raided a dwelling-tower on the way and seized women. They've gone off on the metal roads through the jungle!" He tried to ease his collar. Aten, still watching the green beam, croaked another sentence. "Those devils have got Evelyn!" cried Tommy hoa.r.s.ely. "My G.o.d! Aten's wife, and his...." He jerked a hand toward the Councilor. "Fifty women--gone through the jungle with them, toward Rahn! Those devils have got Evelyn!"

He whirled upon Aten, seizing his shoulder, shaking the man as he roared questions.

"No chance of catching them." Far away, in the jungle, the infinitely vivid actinic flame blazed for several seconds. "They've sprayed thermit on the road. It's melted and ruined. It'd take hours to haul the ground vehicles past the gap. They're got arms and lights. They can fight off the beasts and Ragged Men. They'll make Rahn. And then"--he shook with the rage that possessed him--"Jacaro's there with those gunmen of his and his friends the Ragged Men!"

He seemed to control himself with a terrific effort. He turned to the white-bearded Councilor, whose bearing was that of a man stunned by disaster. Tommy spoke measuredly, choosing words with a painstaking care, clipping the words crisply as he spoke.

The Councilor stiffened. Old as he was, an undeniable fighting light came into his eyes. He barked orders right and left. Men woke from the paralysis of shock and fled upon errands of his command. And Tommy turned to Denham and Smithers.

"The women will be safe until dawn," he said evenly. "Our late prisoners can't lose the way--aluminum roads that are no longer much used lead between all the cities--but they won't dare stop in the jungles. They'll go straight on through. They should reach Rahn at dawn or a little before. And at dawn our air fleet will be over the city and they'll give back the women, unharmed, or we'll turn their own trick on them, by G.o.d! It'd be better for Evelyn to die of gas than as--as the Ragged Men would kill her!"

His hands were clenched and he breathed noisily for an instant. Then he swallowed, and went on in the same unnatural calm:

"Smithers, you're going to stay behind, with part of the air fleet.

You'll get aloft before dawn and shoot down any strange aircraft. They might try to stalemate us by repeating their threat, with our guns over Rahn. I'll give orders."

He turned again to the Councilor, who nodded, glanced at Smithers, and repeated the command.