Jamison said hopefully:

"You'll give me some data on plants and animals, Mr. Cochrane? Won't you? I'm doing a book with Bell's pictures, and--"

"Let me alone!" raged Cochrane.

He reached the control-room. Al, the pilot, sat at the controls with an air of special alertness.

"You're all right? For our lined up trip, we ought to leave in about twenty minutes. We'll be pointing just about right then."

"I'm all right," said Cochrane. "And you can take off when you please."

To Jones he said: "How'd you find us? I didn't think it could be done."

"Doctor Holden figured it out," said Jones. "Simple enough, but I was lost! When the ground-shocks came, everybody else ran to the ship. We waited for you. You didn't come." It had been, of course, because Cochrane would not risk taking Babs through a forest in which trees were falling. "We finally had to choose between taking off and crashing. So we took off."

"That was quite right. We'd all be messed up if you hadn't," Cochrane told him.

Jones waved his hands.

"I didn't think we could ever find you again. We were sixty light-years away when that booster effect died out. Then Doctor Holden got on the communicator. He got Earth. The astronomers back there located us and gave us the line to get back by. We found the planet. Even then I didn't see how we'd pick out the valley. But Doc had had 'em checking the shots we transmitted as we were making our landing. We had the whole first approach on film-tape. They put a crowd of map-comparators to work. We went in a s.p.a.ce Platform orbit around the planet, transmitting what we saw from out there--they figured the orbit for us, too--and they checked what we transmitted against what we'd photographed going down. So they were able to spot the exact valley and tell us where to come down. We actually spotted this valley last night, but we couldn't land in the dark."

Cochrane felt abashed.

"I couldn't have done that job," he admitted, "so I didn't think anybody could. Hm. Didn't all this cost a lot of fuel?"

Jones actually smiled.

"I worked out something. We don't use as much fuel as we did. We're probably using too much now. Al--go ahead and lift. I want to check what the new stuff does, anyhow. Take off!"

The pilot threw a switch, and Jones threw another, a newly installed one, just added to his improvised control-column. A light glowed brightly. Al pressed one b.u.t.ton, very gently. A roaring set up outside.

The ship started up. There was practically no feeling of acceleration, this time. The ship rose lightly. Even the rocket-roar was mild indeed, compared to its take-off from Luna and the sound of its first landing on the planet just below.

Cochrane saw the valley floors recede, and mountain-walls drop below.

From all directions, then, vegetation-filled valleys flowed toward the ship, and underneath. Glaciers appeared, and volcanic cones, and then enormous stretches of white, with smoking dots here and there upon it.

In seconds, it seemed, the horizon was visibly curved. In other seconds the planet being left behind was a monstrous white ball, and there were patches of intolerable white sunlight coming in the ports.

And Cochrane felt queer. Jones had given the order for take-off. Jones had determined to leave at this moment, because Jones had tests he wanted to make.... Cochrane felt like a pa.s.senger. From the man who decided things because he was the one who knew what had to be done, he had become something else. He had been absent two nights and part of a day, and decisions had been made in which he had no part--

It felt queer. It felt even startling.

"We're in a modification of the modified Dabney field now," observed Jones in a gratified tone. "You know the original theory."

"I don't," acknowledged Cochrane.

"The field's always a pipe, a tube, a column of stressed s.p.a.ce between the field-plates," Jones reminded him. "When we landed the first time, back yonder, the tail of the ship wasn't in the field at all. The field stretched from the bow of the ship only, out to that last balloon we dropped. We were letting down at an angle to that line. It was like a kite and a string and the kite's tail. The string was the Dabney field, and the directions we were heading was the kite's tail."

Cochrane nodded. It occurred to him that Jones was very much unlike Dabney. Jones had discovered the Dabney field, but having sold the fame-rights to it, he now apparently thought "Dabney Field" was the proper technical term for his own discovery, even in his own mind.

"Back on the moon," Jones went on zestfully, "I wasn't sure that a field once established would hold in atmosphere. I hoped that with enough power I could keep it, but I wasn't sure--"

"This doesn't mean much to me, Jones," said Cochrane. "What does it add up to?"

"Why--the field held down into atmosphere. And we were out of the primary field as far as the tail of the ship was concerned. But this time we landed, I'd hooked in some ready-installed circuits. There was a second Dabney field from the stern of the ship to the bow. There was the main one, going out to those balloons and then back to Earth. But there was--and is--a second one only enclosing the ship. It's a sort of bubble. We can still trail a field behind us, and anybody can follow in any sort of ship that's put into it. But now the ship has a completely independent, second field. Its tail is never outside!"

Cochrane did not have the sort of mind to find such information either lucid or suggestive.

"So what happens?"

"We have both plates of a Dabney field always with us," said Jones triumphantly. "We're always in a field, even landing in atmosphere, and the ship has practically no ma.s.s even when it's letting down to landing.

It has weight, but next to no ma.s.s. Didn't you notice the difference?"

"Stupid as it may seem, I didn't," admitted Cochrane. "I haven't the least idea what you're talking about."

Jones looked at him patiently.

"Now we can shoot our exhaust out of the field! The ship-field, not the main one!"

"I'm still numb," said Cochrane. "Multiple sclerosis of the brain-cells, I suppose. Let me just take your word for it."

Jones tried once more.

"Try to see it! Listen! When we landed the first time we had to use a lot of fuel because the tail of the ship wasn't in the Dabney field. It had ma.s.s. So we had to use a lot of rocket-power to slow down that ma.s.s.

In the field, the ship hasn't much ma.s.s--the amount depends on the strength of the field--but rockets depend for their thrust on the ma.s.s that's thrown away astern. Looked at that way, rockets shouldn't push hard in a Dabney field. There oughtn't to be any gain to be had by the field at all. You see?"

Cochrane fumbled in his head.

"Oh, yes. I thought of that. But there is an advantage. The ship does work."

"Because," said Jones, triumphant again, "the field-effect depends partly on temperature! The gases in the rocket-blast are hot, away up in the thousands of degrees. They don't have normal inertia, but they do have what you might call heat-inertia. They acquire a sort of fict.i.tious ma.s.s when they get hot enough. So we carry along fuel that hasn't any inertia to speak of when it's cold, but acquires a lunatic sort of subst.i.tute for inertia when it's genuinely hot. So a ship can travel in a Dabney field!"

"I'm relieved," acknowledged Cochrane. "I thought you were about to tell me that we couldn't lift off the moon, and I was going to ask how we got here."

Jones smiled patiently.

"What I'm telling you now is that we can shoot rocket-blasts out of the Dabney field we make with the stern of the ship! Landing, we keep our fuel and the ship with next to no ma.s.s, and we shoot it out to where it does have ma.s.s, and the effect is practically the same as if we were pushing against something solid! And so we started off with fuel for maybe five or six landings and take-offs against Earth gravity. But with this new trick, we've got fuel for a couple of hundred!"

"Ah!" said Cochrane mildly. "This is the first thing you've said that meant anything to me. Congratulations! What comes next?"

"I thought you'd be pleased," said Jones. "What I'm really telling you is that now we've got fuel enough to reach the Milky Way."

"Let's not," suggested Cochrane, "and say we did! You've got a new star picked out to travel to?"

Jones shrugged his shoulders. In him, the gesture indicated practically hysterical frustration. But he said:

"Yes. Twenty-one light-years. Back on Earth they're anxious for us to check on sol-type suns and Earth-type planets."

"For once," said Cochrane, "I am one with the great scientific minds.

Let's go over."