No man would ever know what Kalidasa's aerial palace had really looked like, before it was destroyed by those who sought to extirpate his very name.

“And here he lived, for almost twenty years, awaiting the doom that he knew would come. His spies must have told him that, with the help of the kings of southern Hindustan, Malgara was patiently gathering his armies.”

“And at last Malgara came. From the summit of the Rock, Kalidasa saw the invaders marching from the north. Perhaps he believed himself impregnable; but he did not put it to the test. For he left the safety of his great fortress, and rode out to meet his brother, in the neutral ground between the two armies. One would give much to know what words they spoke, at that last encounter. Some say they embraced before they parted; it may be true.”

“Then the armies met, like the waves of the sea. Kalidasa was fighting on his own territory, with men who knew the land, and at first it seemed certain that victory would go to him. But then occurred another of those accidents that determine the fate of nations.”

“Kalidasa's great war elephant, caparisoned with the royal banners, turned aside to avoid a patch of marshy ground. The defenders thought that the king was retreating. Their morale broke; they scattered, as the Chronicles record, like chaff from the winnowing fan.”

“Kalidasa was found on the battlefield, dead by his own hand. Malgara became king. And Yakkagala was abandoned to the jungle, not to be discovered again for seventeen hundred years.”

“My secret vice,” Rajasinghe called it, with wry amusement but also with regret. It had been years since he had climbed to the summit of Yakkagala, and though he could fly there whenever he wished, that did not give the same feeling of achievement. To do it the easy way by-passed the most fascinating architectural details of the ascent; no-one could hope to understand the mind of Kalidasa without following his footsteps all the way from Pleasure Garden to aerial Palace.

But there was a substitute which could give an ageing man considerable satisfaction. Years ago he had acquired a compact and powerful twenty-centimetre telescope; through it he could roam the entire western wall of the Rock, retracing the path he had followed to the summit so many times in the past. When he peered through the binocular eyepiece, he could easily imagine that he was hanging in mid-air, close enough to the sheer granite wall to reach out and touch it.

In the late afternoon, as the rays of the westering sun reached beneath the rock overhang that protected them, Rajasinghe would visit the frescoes, and pay tribute to the ladies of the court. Though he loved them all, he had his favourites; sometimes he would talk silently to them, using the most archaic words and phrases that he knew-well aware of the fact that his oldest Taprobani lay a thousand years in their future.

It also amused him to watch the living, and to study their reactions as they scrambled up the Rock, took photographs of each other on the summit, or admired the frescoes. They could have no idea that they were accompanied by an invisible-and envious– spectator, moving effortlessly beside them like a silent ghost, and so close that he could see every expression, and every detail of their clothing. For such was the power of the telescope that, if Rajasinghe had been able to lip-read, he could have eavesdropped on the tourists' conversation.

If this was voyeurism, it was harmless enough – and his little “vice” was hardly a secret, for he was delighted to share it with visitors. The telescope provided one of the best introductions to Yakkagala, and it had often served other useful purposes. Rajasinghe had several times alerted the guards to attempted souvenir hunting, and more than one astonished tourist had been caught carving his initials on the face of the Rock.

Rajasinghe seldom used the telescope in the morning, because the sun was then on the far side of Yakkagala and little could be seen on the shadowed western face. And, as far as he could recall, he had never used it so soon after dawn, while he was still enjoying the delightful local custom of “bed-tea”, introduced by the European planters three centuries ago. Yet now, as he glanced out of the wide picture-window that gave him an almost complete view of Yakkagala, he was surprised to see a tiny figure moving along the crest of the Rock, partly silhouetted against the sky. Visitors never climbed to the top so soon after dawn – the guard wouldn't even unlock the elevator to the frescoes for another hour. Idly, Rajasinghe wondered who the early bird could be.

He rolled out of bed, clambered into his bright batik sarong, and made his way, bare-bodied, out on to the verandah, and thence to the stout concrete pillar supporting the telescope. Making a mental note, for about the fiftieth time, that he really should get the instrument a new dust-cover, he swung the stubby barrel towards the Rock.

“I might have guessed it!” he told himself with considerable pleasure, as he switched to high power. So last night's show had impressed Morgan, as well it should have done. The engineer was seeing for himself, in the short time available, how Kalidasa's architects had met the challenge imposed upon them.

Then Rajasinghe noticed something quite alarming. Morgan was walking briskly around at the very edge of the plateau, only centimetres away from the sheer drop that few tourists ever dared to approach. Not many had the courage even to sit in the Elephant Throne, with their feet dangling over the abyss; but now the engineer was actually kneeling beside it, holding on to the carved stonework with one casual arm – and leaning right out into nothingness as he surveyed the rock-face below. Rajasinghe, who had never been very happy even with such familiar heights as Yakkagala's, could scarcely bear to watch.

After a few minutes of incredulous observation, he decided that Morgan must be one of those rare people who are completely unaffected by heights. Rajasinghe's memory, which was still excellent but delighted in playing tricks on him, was trying to bring something to his notice. Hadn't there once been a Frenchman who had tightroped across Niagara Falls, and even stopped in the middle to cook a meal? If the documentary evidence had not been overwhelming, Rajasinghe would never have believed such a story.

And there was something else that was relevant here – an incident that concerned Morgan himself. What could it possibly be? Morgan… Morgan… he had known virtually nothing about him until a week ago.

Yes, that was it. There had been a brief controversy that had amused the news media for a day or so, and that must have been the first time he had ever heard Morgan's name.

The Chief Designer of the proposed Gibraltar Bridge had announced a startling innovation. As all vehicles would be on automatic guidance, there was absolutely no point in having parapets or guard rails at the edge of the roadway; eliminating them would save thousands of tons. Of course, everyone thought that this was a perfectly horrible idea; what would happen, the public demanded, if some car's guidance failed, and the vehicle headed towards the edge? The Chief Designer had the answers; unfortunately, he had rather too many.

If the guidance failed, then as everyone knew the brakes would go on automatically, and the vehicle would stop in less than a hundred metres. Only on the outermost lanes was there any possibility that a car could go over the edge; that would require a total failure of guidance, sensors and brakes, and might happen once in twenty years.

So far, so good. But then the Chief Engineer added a caveat. Perhaps he did not intend it for publication; possibly he was half-joking. But he went on to say that, if such an accident did occur, the quicker the car went over the edge without damaging his beautiful bridge, the happier he would be.