The edge of the basket was padded with suede, and from each corner rose a pillar, the pillars supporting a complicated contraption of stainless steel piping in two coils which was, Stafford supposed, the burner which heated the air. Beyond the basket the multi-coloured balloon envelope was laid out on the ground. It was bigger than he expected and looked flimsy. Four black Kenyans were stretching it out and straightening wire ropes.

He turned to Hunt. 'It's bigger than I expected.' He didn't mention the flimsiness.

'She's a Cameron N-84. That means she's 84,000 cubic feet in volume. When she's inflated the height from the floor of the basket to the crown of the balloon is over 60 feet.'

'What's the fabric?'

'Close weave nylon treated with polyurethane to close the pores. This envelope is nearly new; the old one became too porous and I was losing air and efficiency. It's the ultraviolet that does it, of course. Even though the fabric is specially treated the sun gets it in the end. A balloon doesn't last nearly as long here as it would in England. I'll give the boys a hand.'

Hunt walked forward and began checking rigging. Stafford turned to see Judy. working on the basket. She was clamping a big plate camera on to the side. 'Can I help?'

She smiled. 'I've just finished. We'll be leaving in ten minutes.'

'So soon?' He looked at the flaccid nylon envelope and wondered how.

Hunt came back. 'All right; let's get this thing into the air. Lucas, get the fan. Chuma, you're for the crown rope. You others start flapping.' He turned to Stafford. 'Max, you help us get the basket on its side, slow and easy.'

They tipped the basket over so that the burners pointed to the balloon. Two Kenyans were flapping the nylon, driving air into the envelope. It billowed enormously in slow waves and visibly expanded. Lucas came behind with the fan; it was like an over-sized electric fan but driven by a small Honda petrol engine. The engine sputtered and then caught with a roar, driving air into the balloon.

Hunt got into the basket and crouched behind the burners. He lit the pilot flames and then tilted the burners towards the balloon. 'All right, Lucas,' he said, raising his voice above the noise of the fan. 'Join Chuma on the crown rope. Judy and Max to the basket.'

Stafford and Judy stood on each side of the basket. He did not know what to do but was prepared to follow her lead. The balloon was filling rapidly and suddenly there was a growling, deep-throated roar and a blue flame, six feet long and nearly a foot in diameter, shot into the open throat of the balloon. It took Stafford by surprise and he started, then looked towards Judy. She was laughing so he grinned back weakly.

The roar went on and on, and the balloon expanded like a blossoming flower caught in time-lapse photography. Hunt switched off the flame, and one of the Kenyans turned off the fan and there was blessed silence. Hunt looked up as the ballon rose above them. 'All hands to the basket,' he said, and sent another burst of flame into the balloon.

The two Kenyans joined Stafford and Judy as the basket began to stir like a live thing. Slowly it began to tilt upright as the flame poured heat into the envelope. Hunt switched off again, and shouted, 'Let go the crown rope.' Immediately the basket became upright as the balloon surged above them. 'All hands on,' said Hunt, and four pairs of black hands clamped on the padded edges. 'Max, get in.'

There was a sort of footstep in the wickerwork so Stafford put his foot in it and swung his other leg inboard. Hunt caught his arm and helped him regain balance. Judy climbed in from the other side. She immediately began to turn a valve on one of the cylinders of which there were four, one in each corner of the basket. Hunt was giving short blasts of flame, a few seconds at a time. It seemed to Stafford as though he was doing some kind of fine tuning. Once he said, 'Hands off,' and then, almost immediately, 'Hands on.'

Lucas was rolling a cylinder along the ground towards the basket. Judy unstrapped the cylinder she had been working on and exchanged it for the one brought by Lucas. Then she tapped her brother on the shoulder. 'Okay to go.'

He released a sustained flame, then said 'Hands off.' For a moment nothing apparently happened and then Stafford became aware that they were airborne. The ground was dropping away as they rose in complete silence, and the slight breeze he had felt on the ground had disappeared.

Hunt said, 'The wind is just right. We'll pass over Jim's vegetable patch, take our pictures, and we're set for Hell's Gate. But we'll get some height for the photographs.' The burner roared and Stafford felt heat on his face as he looked up into the vast, empty interior of the envelope into which the flame was disappearing. When he looked down again the ground was receding even faster and the landscape was opening out.

Hunt pointed. 'The College. We'll pass over it. You ready, Judy?'

She bent down to look through a viewfinder. 'Everything okay.'

Stafford produced his own camera. It was a Pentax 110; not a 'spy' camera like the Minox, but still small enough to be carried unobtrusively in a pocket. It also came with a selection of good lenses.

The noise of the burner stopped. 'We'll still rise a bit,' said Hunt conversationally. 'What do you think of it?'

To Stafford's surprise all his qualms had gone. 'I think it's bloody marvellous,' he said. 'So peaceful. Except for the noise of the burner, but that isn't on all the time.'

'There's Dirk Hendriks down there,' said Hunt. 'Talking to Brice outside the Admin Block.' He waved. 'If we were lower we could have a chat.'

'How high are we?'

'Getting on for 2,000 feet from point of departure. That's about 8,000 feet above sea level. The experimental plots are coming up, Judy.'

'I see them.' She took about ten photographs while Stafford took some of his own and then straightened. 'That's it,' she said. 'The work's done. Now for the pleasurable bit.'

'About the noise of the burner,' said Hunt. 'It's difficult to make a quiet burner; I'd say impossible. This one up here is rated at ten million Btu – that's about 4,000 horsepower. You can't keep that lot quiet when it's ripping loose.'

'You're kidding,' Stafford said unbelievingly.

'No, it's quite true. One of the gas cylinders will provide the average household with two months' cooking – we use it up in less than half an hour. But we're not operating at maximum efficiency, so I reckon we're getting about 3,000 horsepower. In England and America they use propane but that's a bit tricky in the African heat so we use butane which has a lesser calorific value. And we have to add pressure with nitrogen; that's what that little cylinder there is for.'

Stafford found the power of the burner hard to believe. Hunt said, 'This dial tells the temperature – not here, but at the crown of the balloon up there.' He jerked his thumb upwards. 'Optimum temperature is 100 degrees Celsius.'

'But that's the boiling point of water.'

'Quite so,' Hunt said equably. 'If it gets above 110 degrees I'm in trouble – the nylon doesn't like it – so I keep a careful eye on the bloody gauge.'

'We're coming up to the entrance of Hell's Gate,' said Judy. 'Alan, come low over Fischer's Column.'

'Okay, but I'll have to go up after that.' He produced a packet of cigarettes and offered one. As Stafford looked doubtfully at the cylinders of butane surrounding them Hunt smiled, and said, 'Quite safe; it'll just add a bit more hot air."

They drifted into the gorge of Hell's Gate through a gap in sheer cliffs. Hunt occasionally reached up to the burner controls and gave a short blast. Apart from that it was quiet and Stafford could hear cicadas chirping and the twittering of birds. The smoke from his cigarette ascended lazily in a spiral and he realized that was because they were moving at; the same speed as the wind. It was weird.