The Year of Rice and Salt

'And motion is easiest of all to study,' Iwang said. 'We can try all manner of things with motion. We can time this attraction of things to the Earth. We can see if the speed is the same up in the hills and down in the valleys. Things speed up as they fall, and this might be measurable too. Light itself might be measurable. Certainly the angles of refraction are constant, I've measured those already.'

Khalid was nodding. 'First this reverse bellows, to empty a chamber. Although surely it cannot be a true void that results. Nothingness is not possible in this world, I think. There will be something in there, thinner than air.'

'That is more Aristotle,' Iwang said. Natureabhors the void." But what if it doesn't? We will only know when we try.'

Khalid nodded. If he had had two hands he would have been rubbing them together.

The three of them walked out to the waterworks. Here a canal brought a hard flow from the river, its gliding surface gleaming in the morning light. The water powered a mill, which geared out to axles turning a bank of heavy metal working hammers and stamps, and finally the rotating bellows handles that powered the blast furnaces. It was a noisy place, filled with sounds of falling water, smashed rock, roaring fire, singed air; all the elements raging with transmutation, hurting their cars and leaving a burnt smell in the air. Khalid stood watching the waterworks for a while. This was his achievement, he was the one who had organized all the artisans' skills into this enormous articulated machine, so much more powerful than people or horses had ever been. They were the most powerful people in all the history of the world, Bahram thought, because of Khalid's enterprise; but with a wave Khalid dismissed it all. He wanted to understand why it worked.

He led the other two back to the shop. 'We'll need your glassblowing, and my leather and iron workers,' he said. 'The valve you mention could perhaps be made of sheep intestines.'

'It might have to be stronger than that,' said Iwang. 'A metal gate of some sort, pressed into a leather gasket by the suck of the void.'

'Yes.'

No Jinn in This Bottle

Khalid set his artisans to the task, and Iwang did the glassblowing, and after a few weeks they had a two part mechanism: a thick glass globe to be emptied, and a powerful pump to empty it. There were any number of collapses, leaks and valve failures, but the old mechanists of the compound were ingenious, and attacking the points of failure, they ended up with five very similar versions of the device, all very heavy. The pump was massive and lathed to newly precise fits of plunger, tube and valves; the glass globes were thick flasks, with necks even thicker, and knobs on the inside surfaces from which objects could be hung, to see what would happen to them when the air in the globe was evacu ated. When they solved the leakage problems, they had to build a rackand pinion device to exert enough force on the pump to evacuate the final traces of air from the globe. Iwang advised them not to create such a perfect void that they ended up sucking in the pump, the compound, or perchance the whole world, like jinni returning to their confinement; and as always, Iwang's stone face did not give them any clue as to whether he was joking or serious.

When they had the mechanisms working fairly reliably (occasionally one would still crack its glass, or break a valve), they set one on a wooden frame, and Khalid began a sequence of trials, inserting things in the glass globes, pumping out the air, and seeing what resulted. All philosophical questions on the nature of what remained inside the globe after the air was removed, he now refused to address. 'Let's just see what happens,' he said. 'It is what it is.' He kept big blank paged books on the table beside the apparatus, and he or his clerks recorded every detail of the trials, timing them on his best clock.

After a few weeks of learning the apparatus and trying things, he asked Iwang and Bahram to arrange a small party, inviting several of the qadi and teachers from the madressas in the Registan, particularly the mathematicians and astronomers of Sher Dor Madressa, who were already involved in discussions of ancient Greek and classical caliphate notions of physical reality. On the appointed day, when all those invited had gathered in the open walled workshop next to Khalid's study, Khalid introduced the apparatus to them, describing how it worked and indicating what they could all see, that he had hung an alarm clock from a knob inside the glass globe, so that it swung freely at the end of a short length of silk thread. Khalid cranked the piston of the rack and pinion down twenty times, working hard with his left arm. He explained that the alarm clock was set to go off at the sixth hour of the afternoon, shortly after the evening prayers would be sung from Samarqand's northernmost minaret.