Russ reached out and jerked a calculator toward him. Rapidly he set up the equations, pressed the tabulator lever. The machine gurgled and chuckled, clicked out the result. Bending over to read it, Russ sucked in his breath.

"It's working out right," he said.

"That'll mean new equipment, lots of it," Greg pointed out. "Wilson's gone, d.a.m.n him. Who's going to help us?"

"We'll do it ourselves," said Russ. "When we're the only ones here, we can be sure there won't be any leak."

It took hours of work on the math machines, but at the end of that time Russ was certain of his ground.

"Now we go to work," he said, gleefully.

In a week's time they had built a triple televisor, but simplifications of the standard commercial set gave them a mechanism that weighed little more and was far more efficient and accurate.

During the time the work went on they maintained a watch over both the office of Spencer Chambers and the laboratory in which Dr. Herbert Craven worked 16 hours a day. Unseen, unsuspected, they were silent companions of the two men during many hours. They read what the men wrote, read what was written to them, heard what they said, saw how they acted. Doing so, the pair in the high mountain laboratory gained a deep insight into the characters of unsuspecting quarries.

"Both utterly ruthless," declared Greg. "But apparently men who are sincere in thinking that the spoils belong to the strong. Strange, almost outdated men. You can't help but like Chambers. He's good enough at heart. He has his pet charities. He really, I believe, wants to help the people. And I think he actually believes the best way to do it is to gain a dictatorship over the Solar System. That ambition rules everything in his life. It has hardened him and strengthened him. He will crush ruthlessly, without a single qualm, anything that stands in his path. That's why we'll have a fight on our hands."

Craven seemed to be making little progress. They could only guess at what he was trying to develop.

"I think," said Russ, "he's working on a collector field to suck in radiant energy. If he really gets that, it will be something worth having."

For hours Craven sat, an intent, untidy, unkempt man, sunk deep in the cushions of an easy chair. His face was calm, with relaxed jaw and eyes that seemed vacant. But each time he would rouse himself from the chair to pencil new notations on the pads of paper that littered his desk. New ideas, new approaches.

The triple televisor was completed except for one thing.

"Sound isn't so easy," said Russ. "If we could only find a way to transmit it as well as light."

"Listen," said Greg, "why don't you try a condenser speaker."

"A condenser speaker?"

"Sure, the gadget developed way back in the 1920s. It hasn't been used for years to my knowledge, but it might do the trick."

Russ grinned broadly. "h.e.l.l, why didn't I think of that? Here I've been racking my brain for a new approach, a new wrinkle ... and exactly what I wanted was at hand."

"Should work," declared Greg. "Just the opposite of a condenser microphone. Instead of radiating sound waves mechanically, it radiates a changing electric field and this field becomes audible directly within the ear. Even yet no one seems to understand just how it works, but it does ... and that's good enough."

"I know," said Russ. "It really makes no sound. In other words it creates an electric field that doubles for sound. It ought to be just the thing because nothing can stop it. Metal shielding can, I guess, if it's thick enough, but it's got to be pretty d.a.m.n thick."

It took time to set the mechanism up. Ready, the ma.s.sive apparatus, within which glowed a larger and more powerful force field, was operated by two monstrous material energy engines. The controls were equipped with clockwork drives, designed so that the motion of the Earth could be nullified completely and automatically for work upon outlying planets.

Russ stood back and looked at it. "Stand in front of that screen, Greg,"

he said, "and we'll try it on you."

Greg stepped in front of the screen. The purr of power came on.

Suddenly, materializing out of the air, came Greg's projection. Hazy and undefined at first, it rapidly a.s.sumed apparent solidity. Greg waved his arm; the image moved its arm.

Russ left the controls and walked across the laboratory to inspect the image. Examined from all sides, it looked solid. Russ walked through it and felt nothing. There was nothing there. It was just a three-dimensional image. But even from two feet away, it was as if the man himself stood there in all the actuality of flesh and blood.

"h.e.l.lo, Russ," the image whispered. It held out a hand. "Glad to see you again."

Laughing, Russ thrust out his hand. It closed on nothing in mid-air, but the two men appeared to shake hands.

They tested the machine that afternoon. Their images strode above the trees, apparently walking on thin air. Gigantic replicas of Greg stood on a faraway mountain top and shouted with a thunderous voice. Smaller images, no more than two inches high, shinnied up a table leg.

Satisfied, they shut off the machine.

"That's one of the possibilities you mentioned," suggested Russ.

Greg nodded grimly.

An autumn gale pelted the windows with driving rain, and a wild, wet wind howled through the pines outside. The fire was leaping and flaring in the fireplace.

Deep in his chair, Russ stared into the flame and puffed at his pipe.

"The factory wants more money on the s.p.a.ceship," said Greg from the other chair. "I had to put up some more shares as collateral on a new loan."

"Market still going down?" asked Russ.

"Not the market," replied Greg. "My stocks. All of them hit new lows today."

Russ dragged at the pipe thoughtfully. "I've been thinking about that stock business, Greg."

"So have I, but it doesn't seem to do much good."

"Look," said Russ slowly, "what planets have exchanges?"

"All of them except Mercury. The Jovian exchange is at Ranthoor. There's even one out at Pluto. Just mining and chemical shares listed, though."

Russ did not reply. Smoke curled up from his pipe. He was staring into the fire.

"Why do you ask?" Greg wanted to know.

"Just something stirring around in my mind. I was wondering where Chambers does most of his trading."

"Ranthoor now," said Greg. "Used to do it on Venus. The listing is larger there. But since he took over the Jovian confederacy, he switched his business to it. The transaction tax is lower. He saw to that."

"And the same shares are listed on the Callisto market as on the New York boards?"

"Naturally," said Greg, "only not as many."

Russ watched the smoke from his pipe. "How long does it take light to travel from Callisto to Earth?"