«All right, the hull turned to dust and blew away, What does that mean? It means we've got a faulty hull, and I'm going to sue the hind legs off General Products when we get back. But do you know what caused it?»

«No.»

«So why do you assume it's some kind of threat?»

«Tell you what I'll do,» I said. I turned the ship until it was tail down to Cannonball Express. «Now. We'll be there in three hours if you insist on landing. It's your ship, just as you say. But I'm going to try to talk you out of it.»

«That's fair.»

«Have you had space-pilot training?»

«Naturally.»

«Did it include a history of errors course?»

«I don't think so. We got a little history of the state of the art.»

«That's something. You remember that they started out with chemical fuels and that the first ship to the asteroids was built in orbit around Earth's moon?»

«Uh huh.»

«This you may not have heard. There were three men in that ship, and when they were launched, it was in an orbit that took them just slightly inside the moon's orbit, then out again and away. About thirty hours after launching the men noticed that all their ports were turning opaque. A concentration of dust in their path was putting little meteor pits all through the quartz. Two of the men wanted to continue on, using instruments to finish their mission. But the third man was in command. They used their rockets and stopped themselves dead.

«Remember, materials weren't as durable in those days, and nothing they were using had been well tested. The men stopped their ship in the orbit of the moon, which by then was 230,000 miles behind them, and called base to say they'd aborted the mission.»

«You remember this pretty well. How come?»

«They drilled these stories into us again and again. Everything they tried to teach us was illustrated with something from history. It stuck.»

«Go on.»

«They called base and told them about their windows fogging up. Somebody decided it was dust, and someone else suddenly realized they'd launched the ship through one of the moon's Trojan points.»

Elephant laughed, then coughed. «Wish I hadn't breathed so much vacuum. I gather you're leading up to something.»

«If the ship hadn't stopped, it would have been wrecked. The dust would have torn it apart. The moral of this story is, anything you don't understand is dangerous until you do understand it.»

«Sounds paranoid.»

«Maybe it does to a flatlander. You come from a planet so kind to you, so seemingly adapted to you, that you think the whole universe is your oyster. You might remember my neutron star story. I'd have been killed if I hadn't understood that tidal effect in time.»

«So you would. So you think flatlanders are all fools?»

«No, Elephant. Just not paranoid enough. And I refuse to apologize.»

«Who asked you?»

«I'll land with you if you can tell me what made our hull turn tp dust.»

Elephant crossed his arms and glared forward. I shut up and waited.

By and by he said, «Can we get home?»

«I don't know. The hyperdrive motor will work, and we can use the gravity drag to slow us down to something like normal. Physically we should be able to do it.»

«Okay. Let's go. But I'll tell you this, Bey. If I were alone, I'd go down, and damn the hull.»

So we turned tail and ran, under protest from Elephant. In four hours we were far enough from Cannonball Express's gravity well to enter hyperspace.

I turned on the hyperdrive, gasped, and turned it off just as fast as I could. We sat there shaking, and Elephant said, «We can inflate the bubble.»

«But can we get in?»

«It doesn't have an air lock.»

We worked it, though. There was a pressure-control dial in the cabin, and we set it for zero; the electromagnetic field that folded the bubble would now inflate it without pressure. We went inside, pressurized it, and took off our helmets.

«We're out of the radiation field,» said Elephant. «I looked.»

«Good.» You can go pretty far in even a couple of seconds of hyperdrive. «Now, there's one thing I've got to know. Can you take that again?»

Elephant shuddered. «Can you?»

«I think so. I can do all the navigating if I have to.»

«Anything you can take, I can take.»

«Can you take it and stay sane?»

«Yes.»

«Then we can trade off. But if you change your mind, let me know that instant. A lot of good men have left their marbles in the Blind Spot, and all they had were a couple of windows.»

«I believe you. Indeed I do, sir. How do we work it?»

«We'll have to chart a course through the least dense part of space. The nearest inhabited world is Kzin. I hate to risk asking help from the kzinti, but we may have to.»

«Tell you what, Bey. Let's at least try to reach Jinx. I want to use that number of yours to give the puppeteers hell.»

«Sure. We can always turn off to something closer.»

I spent an hour or so working out a course. When I'd finished, I was pretty sure we could navigate it without either of us having to leave the bubble more than once every twenty-four hours to look at the mass indicator. We threw fingers for who got the first watch, and I lost.

We put on our suits and depressurized the bubble. As I crawled through the manhole, I saw Elephant opaqueing the bubble wall.

I squeezed into the crash couch, all alone among the stars. They were blue ahead and red behind when I finished turning the ship. I couldn't find the protosun.

More than half the view was empty space. I found myself looking thoughtfully at the air lock. It was behind and to the left, a metal oblong standing alone at the edge of the deck, with both doors tightly closed. The inner door had slammed when the pressure dropped, and now the air lock mechanisms guarded the pressure inside against the vacuum outside in both directions. Nobody inside to use the air, but how do you explain that to a pressure sensor?

I was procrastinating. The ship was aimed; I clenched my teeth and sent the ship into hyperspace.

The Blind Spot, they call it. It fits.

There are ways to find the blind spot in your eye. Close one eye, put two dots on a piece of paper, and bring the paper toward you, focusing on one of the dots. If you hold the paper just right, the other dot will suddenly vanish.

Let a ship enter hyperspace with the windows transparent, and the windows will seem to vanish. So will the space enclosing them. Objects on either side stretch and draw closer together to fill the missing space. If you look long enough, the Blind Spot starts to spread; the walls and the things against the walls draw even closer to the missing space until they are engulfed.

It's all in your mind, they tell me. So?

I turned the key, and half my view was Blind Spot. The control board stretched and flowed. The mass-indicator sphere tried to wrap itself around me. I reached for it, and my hands were distorted, too. With considerable effort I put them back at my sides and got a grip on myself.

There was one fuzzy green line in the plastic distortion that had been a mass indicator. It was behind and to the side. The ship could fly itself until Elephant's turn came. I fumbled my way to the manhole and crawled through.

Hyperspace was only half the problem.

It was a big problem. Every twenty-four hours one of us had to go out there, see if there were any dangerous masses around, drop back to normal space to take a fix and adjust course. I found myself getting unbearably tense during the few hours before each turn. So did Elephant. At these times we didn't dare talk to each other.

On my third trip I had the bad sense to look up — and went more than blind. Looking up, there was nothing at all in my field of vision, nothing but the Blind Spot.