By the time J reached that thought, he had also reached the end of his cigar. Since he couldn't think of anything else that needed his attention that night, he went to bed.

Blade appeared at the Tower of London promptly at ten o'clock Wednesday morning. To J's eyes he showed no sign of as much as a shaving-nick, let alone having been in a train wreck.

«I gather the doctor gave you a clean bill of health?» said J.

«Absolutely, sir,» replied Blade. «He couldn't find anything except a bit of bruising on the scalp.»

«What about the X-rays?»

«Nothing showed up on those either. It seems I still have the same old hard head.»

«That's good. It would be a trifle on the silly side to have you survive twenty-odd trips and then buy it in a train wreck here in England.»

«I quite agree.» J's words were a monumental understatement. For all his qualities of mind and body, Blade also knew that he was still alive partly because of good luck that could run out at any time. It certainly would be bloody silly to have it run out here in England, when he spent so much time in so much danger in Dimension X.

Blade reached up to press the elevator button. «I see you're wearing a ring,» said J, looking at the raised hand. «Ruby?»

«Yes. Nothing really fancy, though. My father gave it to me when I left Eton.»

«Are you going to try wearing it into Dimension X?»

Blade recognized the concern in J's voice. The older man didn't care very much for anything that increased the uncertainty of Blade's trips into Dimension X. Blade didn't blame him, particularly after the last trip.

It wasn't quite correct to say that everything had gone wrong the last time, but certainly a lot hadn't gone the way it was planned. Blade had ended up being bounced about from one dimension to another, first with a courtesan from the black-jade city of Kano, then with a Russian secret agent Lord Leighton had sent into Dimension X as a way of disposing of her. It had been nearly the hairiest mission in the whole history of Project Dimension X, and that was saying a good deal.

«Yes, sir, I am. It's small and light, so it won't take up any room or throw me off balance. Also, it's something that's been around me for quite a while. If there are such things as a human body's individual-oh, call them 'vibrations'-it's more likely to be 'in tune' with mine than something like a survival pack or even a survival knife.»

J frowned. «Sounds rather like mystical guesswork to me.»

Blade shrugged. «It could be mystical, and I'll admit it's guesswork. But isn't half the whole Project guesswork?»

J had to laugh. «You're perfectly right. Only don't let Lord Leighton hear you say that. The man will never forgive you,» he added drily. «Ah, here's the elevator.»

The elevator took them two hundred feet below the Tower in a few seconds. Then they walked down a long corridor, passing through a series of electronically monitored security doors to the main computer complex.

The outer rooms of the complex were filled with the supporting equipment and technicians for the main computer. There seemed to be more of both each time Blade came through.

One face was missing from among the technicians, though. Katerina Shumilova, computer technician and crack KGB agent, lay dead in Kano, killed defending the city against the attacks of the fierce Raufi from the desert. Katerina Shumilova, technician, enemy agent, and a woman Blade had loved. This was the only place in Home Dimension that could really remind Blade of her, and perhaps that was just as well. He could and would fight off all his memories of her, but he would be happier not to have to do so very often.

Another, more familiar face peered around the last door at them as they approached it. Lord Leighton was already at work in his private sanctum, the room that housed the main computer. He waved Blade and J on in through the door. Silently it slid shut behind them.

Leighton noticed Blade's ring almost at once. The man was past eighty, his legs twisted by polio, his spine distorted by a hunchback, what little remained of his hair milky white, and his lab coat as rumpled and dirty as an unwashed dish towel. There was nothing wrong with his eyes, however. They missed very little.

Somehow the ring did not touch off an explosion of Leighton's famous temper. Blade had been half-expecting one. The scientist's ego was as great as his genius. He usually took a dim view of anybody else adding to his experiments.

Instead, all that he said was, «You've thought it out, I take it?»

Blade nodded, and repeated what he'd told J. Leighton listened almost politely-another surprise! — then nodded slowly.

«All this seems compatible with my own data. Certainly if there are any incompatabilities, we can't expect to discover them without going ahead. Very well. Wear the ring, and good luck with it.»

J went over to the folding observer's chair, pulled it out of the wall, and sat down. Blade headed for the little changing room carved out of the solid rock of the walls of the computer room.

As he stripped off his clothes, he wondered why Lord Leighton was behaving in such a subdued fashion. It might be simple old age at long last catching up with him, but that was hard to believe. Perhaps Leighton simply felt a little less unsure of himself than before. All the accidents of Blade's last trip had proved beyond any doubt how little anybody really knew about Dimension X, or what went into sending a person there and bringing him back. For all his egotism, Lord Leighton was too honest a man and too good a scientist not to admit ignorance when it was so dramatically demonstrated-or when it would endanger Richard Blade. Blade doubted he'd ever really like the scientist the way he liked J. But certainly he was coming to respect the old boffin more with each crisis.

Blade finished stripping himself, then smeared every inch of skin with a greasy black cream. It smelled dreadful, but it was supposed to prevent electrical burns when Blade was wired into the computer. Perhaps it actually did. Then he stepped out of the changing room, wearing only the grease, the ruby ring, and a small loincloth.

He walked over to the glass booth in the center of the room and sat down in the metal chair inside the booth. The rubber seat of the chair felt chill and slick, almost slimy against his skin. He leaned back and let Lord Leighton go to work.

Lord Leighton bustled about, unwinding long wires in a dozen different colors from the towering, crackle-finished gray consoles of the computer. Each wire ended in a gleaming metal electrode, shaped like a cobra's head. Swiftly but as carefully as a brain surgeon, Leighton taped the electrodes to Blade's skin, one after another, until Blade was covered with them from head to foot. They even hung from his earlobes, his toes, and his penis.

Eventually there were no more electrodes or at least no more places to attach them. Lord Leighton backed away from Blade's chair. Blade felt like raising a hand in salute to the scientist. But he was so completely covered with electrodes and wires that he hardly dared even take a deep breath.

By now the computer was through the preliminary phases of the main sequence. It was time for Lord Leighton to take over, as he always did, for the moment that would send the computer's pulses into Blade's brain, twisting his perceptions, twisting and hurling him out of the chair and the room and London, into Dimension X.

Blade sometimes felt like twitting Lord Leighton about his insistence on manually controlling the huge computer. Did the scientist harbor secret doubts about the computer that was the product of his own genius?

Hardly. All Leighton was doing was not assuming that the computer was completely infallible, and playing human backup at the decisive moment. Blade knew perfectly well the limitations of automatic systems without human backups. He'd outwitted far too many of them as a field agent for MI6. Lord Leighton would have been a fool not to take a hand. No one, not even his worst enemies, had ever called him a fool, or ever would.