It was obvious why they had stopped.
Under the prow, looking south, Joshua saw ocean to his left-hand side, waves glistening like mercury in the moonlight. To the right lay land cloaked with forest green. And spanning the world from left to right, east to west, was another viaduct: slim, glistening in the moonlight, striding on confident pillars out of the ocean and across the land.
‘Just like the last,’ Lobsang said. ‘I mean, the same dimensions, apparently the same material. The night is very clear. I can trace it all the way to the ocean horizon, as straight as I can measure.’
‘Where are we?’
‘About the latitude of South Carolina. Some five hundred miles south of the New York viaduct. Took us around eighteen hours to get here.’
‘OK. So, Lobsang, if this is typical as you keep saying, if the whole world is girdled with these things – if they’re all around five hundred miles apart—’
‘There may be a couple of dozen of them. Of course the distribution may not be a simple spacing with distance, or latitude. We’ve no way of knowing, without a view from orbit.’
‘This is just as you anticipated, it seems, Lobsang. Global. I wonder how long it took them to build all this.’
‘We’ve no meaningful way to answer that question, Joshua. We don’t know how long they’ve been here, on this world. Or how fast they work. I suspect they’ve accelerated their progress since they encountered us. Getting it done before we can react. But that’s only a guess, for now.’
‘OK. But why, Lobsang? What’s it all for? A transport system? Rail lines? Are these aqueducts, like the Romans used to build?’
‘I doubt it’s anything so simple. I could make guesses, but it would not be constructive at this stage.’
Joshua studied him. His face, underlit by the tablets’ glow, was even harder to read than usual. ‘You sound subdued. Are even you in awe of what these beetles are building?’
There was no reply.
‘So, what next?’
Lobsang said thoughtfully, ‘We’ve come under no threat. The beetles must be aware of our movements; we passed over a work party, remember, on the New York viaduct. We are evidently irrelevant to them. And our findings cannot be lost, even if we do not return; I have already sent short-wave radio reports back to Agnes.’
‘You think we should go on. All the way to the equator?’
‘That’s what I suggest.’
‘Then let’s do it.’
The airship forged on, tracking the North American east coast, heading steadily south.
It was evening of this third day of the journey when they came upon the next viaduct, another five hundred miles or so south. This one spanned Florida, at about the latitude of Miami.
They reached the next viaduct south, another five hundred miles or so, about midday of the next day. It cut across the ocean itself with no land in sight, to north or south. Under a cloudy noon sky, the viaduct was difficult to make out against the grey shoulder of the ocean.
‘There’s no Mexico here,’ Joshua said, checking their position on a tablet map.
‘Very observant.’ Lobsang told Joshua that on this world – and on similar worlds in this band – Mesoamerica did not exist, as they knew it from the Datum. ‘Here, the Pacific breaks through into the Gulf of Mexico. And if you were to cross the Atlantic you’d find the Mediterranean flowing through the Middle East into the Arabian Sea. So there is a continuous waterway running all the way around the planet, at about this latitude. As a result the global ocean currents are different. Once, long ago, it was like this on the Datum; the palaeontologists call it the Tethys Sea. In fact some Long Earth geographers call these worlds the Tethys Belt.’
‘I guess that’s one reason the world’s warmer?’
‘Yes. And if they’ve straddled the whole world with a viaduct at this latitude, the beetles must have mostly encountered ocean, on their way around. An incredible feat of engineering.’
Joshua said, ‘And I used to think oil rigs out on the Gulf were impressive.’
‘Onwards, Joshua?’
‘Onwards, Lobsang.’
They came upon the next viaduct at dawn of the next day, the fifth of the journey. It clipped the northern coast of Venezuela – the northern shore of South America, which was, in this world, an island continent separate from the north.
They continued south, leaving the viaduct behind, crossing dense jungle, a green chaos beneath them.
Lobsang said, ‘That forest is probably full of exotic animals of kinds nobody ever encountered before. An island world.’
‘Leave it for your grandchildren to explore, Lobsang.’
On they sailed, heading deeper over the interior of the continent now, riding through another day and into the night. And at about midnight they came to yet another viaduct. This was the equator. Lobsang recommended they wait out the night to see it properly.
They came together at the windows at about six a.m., on the sixth day of their journey.
The airship drifted in the air directly over the viaduct. It ran, Joshua saw, almost parallel to the course of a tremendous river.
‘That must be the local Amazon,’ he said.
‘Yes.’
‘So now what? Do we descend? Down I’ll go with an electronic parrot on my shoulder, just like old times?’
Lobsang forced a smile. ‘We don’t want to provoke any hostility. For now we wait.’
‘For what?’
‘Again, I suspect that when it comes, we won’t be able to miss it.’ He yawned and stretched, quite convincingly. ‘Now might be a good time to make breakfast, Joshua. Anything but chowder …’
‘Fair enough.’ Joshua rummaged through the tiny galley. They had frozen meat and French fries, and energy to spare; he decided to make burgers. As he got to work he said, ‘You know, I said it before, we’re going to have to do this properly.’
‘Properly?’
‘A genuine global survey. Teams of scientists with seismometers and magnetometers and whatever. Geologists and climatologists to predict what’s going to come next. Super-clocks, atomic or some such, to measure the spin-up of the world more accurately than dear Agnes with her pendulums.’
Lobsang grunted. ‘And the President of the United States, to make a formal first contact and hand over a flag and a plaque? You’re correct in principle, Joshua. It might not be so easy to assemble resources like that, not like it used to be. But we should try—’
A blinding light filled the cabin, a glare that shifted like a swinging searchlight beam. They both ducked, instinctively. It was as if some tremendous craft was flying over the airship.
Joshua dumped the food he was handling and ran forward to the window. He saw a fireball, burning and spitting, scrape its way across the pale equatorial sky, leaving behind a contrail of feathery white vapour. It was heading dead east, out towards the mouth of the Amazon and the ocean.
And now the sound hit them, a tremendous cracking boom that made the gondola shudder.
‘My God.’
Lobsang was smiling grimly. ‘I told you we couldn’t miss it, when it came. How long have we been here? Six hours? There must be several passes like that per day.’
‘What the hell was that?’
‘At a first guess, I’d say it was probably a mass of moon rock, wrapped in some kind of electrically conductive shell. We’ve glimpsed operations on the moon before, remember. That rock must be one of a stream, pouring past the Earth, skimming the atmosphere. As they must have been for years now. This is how they’re spinning up the Earth, Joshua. The beetles. With these latitude bands, and the hurtling space rocks. They turned this whole planet into a huge electrical motor. And they’ve only just begun.’