Iwang was shaking his head. “The mirror might have to be very far away to give the recorder time to determine an interval, and then the lantern flash would not be visible unless the mirror were perfectly angled.”
“Make a person the mirror,” Bahram suggested. “When the person on the far hill sees the first lantern light, he reveals his, and a person next to the first person times the appearance of the second light.”
“Very good,” several people said at once. Iwang added, “It may still be too fast.”
“It remains to be seen,” Khalid said cheerfully. “A demonstration will clarify the issue.”
With that Esmerine and Fedwa wheeled in the ice tray and its ‘demonstration of sherbets’ as Iwang termed it, and the crowd fell to, talking happily, Iwang speaking of the thin sound of goraks in the high Himalaya where the air itself was thin, and so on.
The Khan Confronts the Void
So Iwang brought Khalid back out of his black melancholy, and Bahram saw the wisdom of Iwang’s approach to the matter. Every day now, Khalid woke up in a hurry to get things done. The businesses of the compound were given over to Bahram and Fedwa and the old hands heading each of the shops, and Khalid was distracted and uninterested if they came to him with matters of that sort. All his time was taken by conceiving, planning, executing and recording his demonstrations with the void pump, and later with other equipment and phenomena. They went to the great western city wall at dawn when all was quiet, and timed the sound of wood blocks slapped together and their returning echoes, measuring their distance from the wall with a length of string one third of a li long. Iwang did the calculations, and soon declared that the speed of sound was something like two thousand li an hour, a speed that everyone marvelled at. “About fifty times faster than the fastest horse,” Khalid said, regarding Iwang’s figures happily.
“And yet light will be much faster,” Iwang predicted.
“We will find out.”
Meanwhile Iwang was puzzling over the figures. “There remains the question of whether sound slows down as it moves along. Or speeds up for that matter. But presumably it would slow, if it did anything, as the air resisted the shock.”
“Noise gets quieter the further away it is,” Bahram pointed out. “Maybe it gets quieter rather than slower.”
“But why would that be?” Khalid asked, and then he and Iwang were into a deep discussion of sound, movement, causation and action at a distance. Quickly Bahram was out of his depth, being no philosopher, and indeed Khalid did not like the metaphysical aspect of the discussion, and concluded as he always did these days: ‘We will test it.”
Iwang was agreeable. Ruminating over his figures, he said, “We need a mathematics that could deal not only with fixed speeds, but with the speed of the change of a speed. I wonder if the Hindus have considered this.” He often said that the Hindu mathematicians were the most advanced in the world, very far ahead of the Chinese. Khalid had long ago given him access to all the books of mathematics in his study, and Iwang spent many hours in there reading, or making obscure calculations and drawings, on slates with chalk.
The news of their void pump spread, and they frequently met with the interested parties in the madressas, usually the masters teaching mathematics and natural philosophy. These meetings were often contentious, but everyone kept to the ostentatiously formal disputation style of the madressa’s theolo ical debates.
Meanwhile the Hindu caravanserai frequently sheltered booksellers, and these men called Bahram over to have a look at old scrolls, leatheror wood-bound books, or boxes of loose-leaved pages. “Old One-Hand will be interested in what this Brahmagupta has to say about the size of the earth, I assure you,” they would say grinning, knowing that Bahram could not judge.
“This one here is the wisdom of a hundred generations of Buddhist monks, all killed by the Mughals.”
“This one is the compiled knowledge of the lost Frengis, of Archimedes and Euclid.”
Bahram would look through the pages as if he could tell, buying for the most part by bulk and antiquity, and the frequent appearance of numbers, especially Hindu numbers, or the Tibetan ticks that only Iwang could decipher. If he thought Khalid and Iwang would be interested, he haggled with a firmness based on ignorance, “Look this isn’t even in Arabic or Hindi or Persian or Sanskrit, I don’t even recognize this alphabet! How is Khalid to make anything of this?”
“Oh, but this is from the Deccan, Buddhists everywhere can read it, your Iwang will be very happy to learn this!”
Or, “This is the alphabet of the Sikhs, their last guru invented an alphabet for them, it’s a lot like Sanskrit, and the language is a form of Punjabi,” and so on. Bahram came home with his finds, nervous at having spent good money on dusty tomes incomprehensible to him, and Khalid and Iwang would inspect them, and either page through them like vultures, congratulating Bahram on his judgment and haggling skills, or else Khalid would curse him for a fool while Iwang stared at him, marvelling that he could not identify a Travancori accounting book full of shipping invoices (this was the Deccan volume that any Buddhist could read).
• • •
Other attention drawn by their new device was not so welcome. One morning Nadir Devanbegi appeared at the gate with some of the Khan’s guards. Khalid’s servant Paxtakor ushered them across the compound, and Khalid, carefully impassive and hospitable, ordered coffee brought to his study.
Nadir was as friendly as could be, but soon came to the point. “I argued to the Khan that your life be spared because you are a great scholar, philosopher and alchemist, an asset to the khanate, a jewel of Samarqand’s great glory.”
Khalid nodded uncomfortably, looking at his coffee cup. He lifted a finger briefly, as if to say, Enough, and then muttered, “I am grateful, effendi.”
“Yes. Now it is clear that I was right to argue for your life, as word comes to us of your many activities, and wonderful investigations.”
Khalid looked up at him to see if he were being mocked, and Nadir lifted a palm to show his sincerity. Khalid looked down again.
“But I came here to remind you that all these fascinating trials take place in a dangerous world. The khanate lies at the centre of all the trade routes in the world, with armies in all directions. The Khan is concerned to protect his subjects from attack, and yet we hear of cannon that would reduce our cities’ walls in a week or less. The Khan wishes you to help him with this problem. He is sure you will be happy to bring him some small part of the fruits of your learning, to help him to defend the khanate.”
“All my trials are the Khan’s,” Khalid said seriously. “My every breath is the Khan’s.”
Nadir nodded his acknowledgement of this truth. “And yet you did not invite him to your demonstration with this pump that creates a void in the air.”
“I did not think he would be interested in such a small matter.”
“The Khan is interested in everything.”
None of them could tell by Nadir’s face whether he was joking or not.
“We would be happy to display the void pump to him.”
“Good. That would be appreciated. But remember also that he wishes specific help with cannonry, and with defence against cannonry.”
Khalid nodded. “We will honour his wish, effendi.”
After Nadir was gone, Khalid grumbled unhappily. “Interested in everything! How can he say that and not laugh!” Nevertheless he sent a servant with a formal invitation to the Khan, to witness the new apparatus. And before the visit occurred he had the whole compound at work, developing a new demonstration of the pump which he hoped would impress the Khan.
When Sayyed Abdul Aziz and his retinue made their visit, the globe that was to hold the void this time was made of two half globes, one edge mortised to fit the other precisely, with a thin oiled leather gasket placed between the two before the air was pumped out of the space between them, and thick steel braces for each globe, to which ropes could be tied.
Sayyed Abd
ul sat on his cushions and inspected the two halves of the globe closely. Khalid explained to him: ‘When the air is removed, the two halves of the globe will adhere together with great strength.” He placed the halves together, pulled them apart; placed them together again, screwed the pump into the one that had the hole for it, and gestured for Paxtakor to wind the pump out and in and out again, ten times. Then he brought the device over to the Khan, and invited him to try to pull the two halves of the globe apart.
It could not be done. The Khan looked bored. Khalid took the device out to the central yard of the compound, where two teams of three horses each were held waiting. Their draft harnesses were hooked to the two sides of the globe, and the horses led apart until the globe hung in the air between them. When the horses were steadied, still facing away from each other, the horseboys cracked their whips, and the two teams of horses snorted and shoved and skipped as they attempted to pull away; they skittered sideways, shifted, struggled, and all the while the globe hung from the quivering horizontal ropes. The globe could not be pulled apart; even little charges made by the horse teams only brought them up short, staggering.
The Khan watched the horses with interest, but the globe he seemed to disregard. After a few minutes of straining, Khalid had the horses stopped, and he unhooked the apparatus and brought it over to the Khan and Nadir and their group. When he unscrewed the stopcock, the air hissed back into the globe, and the two halves came apart as easily as slices of an orange. Khalid stripped out the smashed leather gasket.
“You see,” he said, “it was the force of the air, or rather the pull of the void, that kept the halves together so strongly.”
The Khan got up to leave, and his retainers rose with him. It seemed he was almost falling asleep. “So?” he said. “I want to blow my enemies apart, not hold them together.” With a wave of his hand he left.
Inside the Night, Inside the Light
This unenthusiastic response on the part of the Khan worried Bahram. No interest in an apparatus that had fascinated the scholars of the madressa; instead, a command to discover some new weapon or fortification that had eluded the hard search of all the armourers of all the ages. And if they failed, the possible punishments were only too easy to imagine. Khalid’s absent hand mocked them from its own kind of void. Khalid would stare at the end of his wrist and say, “Someday all of me will look like you.”
Now he merely looked around the compound. “Tell Paxtakor to obtain new cannon from Nadir for testing. Three at each weight, and all manner of powder and shot.”
“We have powder here.”
“Of course.” A withering glare: “I want to see what they have that is not ours.”
In the days that followed, he revisited all the old buildings of the compounds, the ones he and his old ironmongers had built when they were first making guns and gunpowder for the Khan. In those days, before he and his men had followed the Chinese system and connected the power of their waterwheel to the furnaces, making their first riverpowered blast furnaces and freeing up their crew of young puffers for other work, everything had been small and primitive, the iron more brittle, everything they made rougher, bulkier. The buildings themselves showed it. Now the gears of the waterwheels whirred with all the power of the river, pouring into the bellows and roaring as fire. The chemical pits steamed lemon and lime in the sun, and the puffers packed boxes and ran camels and moved immense mounds of charcoal around the yards. Khalid shook his head at the sight of it all, and made a new gesture, a kind of sweep and punch with his ghost hand. “We need better clocks. We can only make progress if our measurement of time is more exact.”
Iwang puffed his lips when he heard this. “We need more understanding.”
“Yes, yes, of course. Who could dispute that in this miserable world. But all the wisdom of the ages cannot tell us how long it takes flashpowder to ignite a charge.”
• • •
When the days ended the great compound fell silent, except for the grinding of the watermill on the canal. After the resident workers had washed and eaten and said their last prayers of the day, they went to their apartments at the river end of the compound, and fell asleep. The town workers went home.
Bahram dropped onto his bed beside Esmerine, across the room from their two small children, Fazi and Laila. Most nights he was out as soon his head hit the silk of his pillow, exhausted. Blessed slumber.
But often he and Esmerine woke some time after midnight, and sometimes they lay there breathing, touching, whispering conversations that were usually brief and disjointed, other times the longest and deepest conversations they ever had; and if ever they were to make love, now that the children were there to exhaust Esmerine, it would be in the blessed cool and quiet of these midnight hours.
Afterwards Bahram might get up and walk around the compound, to see it in moonlight and check that all was well, feeling the afterglow of love pulse in him; and usually on these occasions he would see the lamplight in Khalid’s study, and pad by to find Khalid slumped over a book, or scribbling left-handed at his writing stand, or recumbent on his couch, in murmured conversation with Iwang, both of them holding tubes of a narghile wreathed by the sweet smell of hashish. If Iwang was there and the men seemed awake, Bahram would sometimes join them for a while, before he got sleepy again and returned to Esmerine. Khalid and Iwang might be speaking of the nature of motion, or the nature of vision, sometimes holding up one of Iwang’s lenses to look through as they talked. Khalid held the position that the eye received small impressions or images of things, sent through the air to it. He had found many an old philosopher, from China to Frengistan, who held the same view, calling the little images ‘eidola’ or ‘simulacra’ or ‘species’ or ‘image’ or ‘idol’ or ‘phantasm’ or ‘form’ or ‘intention’ or ‘passion’ or ,similitude of the agent’, or ‘shadow of the philosophers’, a name that made Iwang smile. He himself believed the eye sent out projections of a fluid as quick as light itself, which returned to the eye like an echo, with the contours of objects and their colours intact.
Bahram always maintained that none of these explanations was adequate. Vision could not be explained by optics, he would say; sight was a matter of spirit. The two men would hear him out, then Khalid would shake his head. “Perhaps optics are not sufficient to explain it, but they are necessary to begin an explanation. It’s the part of the phenomenon that can be tested, you see, and described mathematically, if we are clever enough.”
The cannons arrived from the Khan, and Khalid spent part of every day out on the bluff over the curve in the river, shooting them off with old Jalil and Paxtakor; but by far the bulk of his time was spent thinking about optics and proposing tests to Iwang. Iwang returned to his shop, blowing thick glass balls with cut sides, mirrors concave and convex, and big, perfectly polished triangular rods, which were for him objects of almost religious reverence. He and Khalid spent afternoon hours in the old man’s study with the door closed, having made a little hole in the south wall letting in a chink of light. They put the prism over the hole, and its straight rainbow shone on the walls or a screen they set up. Iwang said there were seven colours, Khalid six, as he called Iwang’s purple and lavender two parts of the same colour. They argued endlessly about everything they saw, at least at first. Iwang made diagrams of their arrangement that gave the precise angles each band of colour bent as it went through the prism. They held up glass balls and wondered why the light did not fractionate in these balls as it did in the prism, when everyone could see that a sky full of minuscule clear balls, that is to say raindrops, hit by low afternoon sunlight, created the towering rainbows that hung east of Samarqand after a rainshower had passed. Many a time when black storms had passed over the city, Bahram stood outside with the two older men observing some truly beautiful rainbows, often double rainbows, a lighter one arched over the brighter one; and sometimes even a third very faint one above that. Eventually Iwang worked up a law of refraction which he assured Khalid would account fo
r all the colours. “The primary rainbow is produced by a refraction as the light enters the raindrop, an internal reflection at the back surfaces, and a second refraction out of the raindrop. The secondary bow is created by light reflected two or three times inside the raindrops. Now look you, each colour has its own index of refraction, and so to bounce around inside the raindrop is to separate each colour out from the others, with them appearing to the eye always in their correct sequence, reversed in the secondary because there is an extra bounce making it upside down, as in my drawing here, see?”
“So if raindrops were crystalline, there would be no rainbows.”
“That’s right, yes. That’s snow. If there was only reflection, the sky might sparkle everywhere with white light, as if filled with mirrors. Sometimes you see that in a snowstorm, too. But the roundness of raindrops means there is a steady change in the angle of incidence between zero and ninety degrees, and that spreads the different rays to an observer here, who must always stand at an angle from forty to fortytwo degrees off from the incoming sunlight. The secondary one appears when the angle is between fifty and a half degrees and fifty-four and a half. See, the geometry predicts the angles, and out here we measure, using this wonderful sky viewer Bahram found for you at the Chinese caravanserai, and it confirms, as precisely as hand can hold, the mathematical prediction!”
“Well, of course,” Khalid said, “but that’s circular reasoning. You get your angles of incidence by observation of a prism, then confirm the angles in the sky by more observation.”
“But one was colours on the wall, the other rainbows in the sky!”
“As above, so below.” This of course was a truism of the alchemists, so there was a dark edge to Khalid’s comment.
The current rainbow was waning as a cloud in the west blocked the sun. The two old men did not notice, however, absorbed as they were in their discussion. Bahram alone was left to enjoy the vibrant colours arcing across the sky, Allah’s gift to show that he would never again drown the world. The two men jabbed fingers at Iwang’s chalkboard and Khalid’s sky device.
The Years of Rice and Salt Page 26