But he had worked on the projection for years, and studied all the alchemical texts he could obtain, including many bought by Bahram in the Hindu caravanserai, including 'The Book of the End of the Search' by jildaki, and jabir Ibn Hayyam's 'Book of Balances', as well as 'The Secret of Secrets', once thought to be lost, and the Chinese text 'Reference Book for the Penetration of Reality'; and Khalid had in his extensive workshops the mechanical capacity to repeat the required distillations at high heat and very good clarities, all seven hundred and seventy-seven times. Two weeks earlier he had declared that his final efforts had borne fruit, and now all was ready for a public demonstration, which of course had to include regal witnesses to matter.

So Bahram hurried around in Khalid's compound on the northern edge of Samarqand, sprawling by the banks of the Zeravshan River, which provided power to the foundries and the various workshops. The walls of the establishment were ringed by great heaps of charcoal waiting to be burned, and inside there were a number of buildings, loosely grouped around the central work area, a yard dotted with vats and discoloured chemical baths. Several different stinks combined to form the single harsh smell that was particular to Khalid's place. He was the khanate's principal gunpowder producer and metallurgist, among other things, and these practical enterprises supported the alchemy that was his ruling passion.

Bahram wove through the clutter, making sure the demonstration area was ready. The long tables in the open walled shops were crowded with an orderly array of equipment; the walls of the shops were neatly hung with tools. The main athanor was roaring with heat.

But Khalid was not to be found. The puffers had not seen him; Bahram's wife Esmerine, Khalid's daughter, had not seen him. The house at the back of the compound seemed empty, and no one answered Bahram's calls. He began to wonder if Khalid had run away in fear.

Then Khalid appeared out of the library next to his study, the only room in the compound with a door that locked.

'There you are,' Bahram said. 'Come on, Father, Al Razi and Mary the Jewess will be no help to you now. It's time to show the world the thing itself, the projection.'

Khalid, startled to see him, nodded curtly. 'I was making the last preparations,' he said. He led Bahram into the furnace shed, where the geared bellows, powered by the waterwheel on the river, pumped air into the roaring fires.

The Khan and his party arrived quite late, when much of the afternoon was spent. Twenty horsemen thundered in, their finery gleaming, and then a camel train fifty beasts long, all foaming at the gallop. The Khan dismounted from his white bay and walked across the yard with Nadir Devanbegi at his side, and several court officials at their heels.

Khalid's attempt at a formal greeting, including the presentation of a gift of one of his most cherished alchemical books, was cut short by Sayyed Adbul Aziz. 'Show us,' the Khan commanded, taking the book without looking at it.

Khalid bowed. 'The alembic I used is this one here, called a pelican. The base matter is mostly calcinated lead, with some mercurials. They have been projected by continuous distillation and re distillation, until all the matter has passed through the pelican seven hundred and seventy seven times. At that point the spirit in the lion well, to put it in more worldly terms, the gold condenses out at the highest athanor heat. So, we pour the wolf into this vessel, and put that in the athanor, and wait for an hour, stirring meanwhile seven times.'

'Show us.' The Khan was clearly bored by the details.

Without further ado Khalid led them into the furnace shed, and his assistants opened the heavy thick door of the athanor, and after allowing the visitors to handle and inspect the ceramic bowl, Khalid grabbed up tongs and poured the grey distillate into the bowl, and placed the tray in the athanor and slid it into the intense heat. The air over the furnace shimmered as Sayyed Abdul Aziz's mullah said prayers, and Khalid watched the second hand of his best clock. Every five minutes he gestured to the puffers, who opened the door and pulled out the tray, at which point Khalid stirred the liquid metal, now glowing orange, with his ladle, seven times seven circles, and then back into the heat of the fire. In the last minutes of the operation, the crackle of the charcoal was the only sound in the yard. The sweating observers, including many acquaintances from the town, watched the clock tick out the last minute of the hour in a silence like that of sufis in a trance of speechlessness, or like, Bahram thought uneasily, hawks inspecting the ground far below.

Finally Khalid nodded to the puffers, and he himself hefted the bowl off the tray with big tongs, and carried it to a table in the yard, cleared for this demonstration. 'Now we pour off the dross, great Khan,' paddling the molten lead out of the bowl into a stone tub on the table. 'And at the bottom we see – ah…'

He smiled and wiped his forehead with his sleeve, gestured at the bowl. 'Even when molten it gleams to the eye.'

At the bottom of the bowl the liquid was a darker red. With a spatula Khalid carefully skimmed off the remaining dross, and there at the bottom of the bowl lay a cooling mass of liquid gold.

'We can pour it into a bar mould while it is still soft,' Khalid said with quiet satisfaction. 'It looks to be perhaps ten ounces. That would be one seventh of the stock, as predicted.'

Sayyed Abdul Aziz's face shone like the gold. He turned to his secretary Nadir Devanbegi, who was regarding the ceramic bowl closely.

Without expression, Nadir gestured for one of the Khan's guards to come forward. The rest of them rustled behind the alchemist's crew. Their pikes were still upright, but they were now at attention.

'Seize the instruments,' Nadir told the head guard.

Three soldiers helped him take possession of all the tools used in the operation, including the great pelican itself. When they were all in hand, Nadir went to one guard and took up the ladle Khalid had used to stir the liquid metals. In a sudden move he smashed it down on the table. It rang like a bell. He looked over at Sayyed Abdul Aziz, who stared at his secretary, puzzled. Nadir gestured with his head to one of the pikemen, then put the ladle on the table.

'Cut it.'

The pike came down hard, and the ladle was sliced just above its scoop. Nadir picked up the handle and the scoop and inspected them. He showed them to the Khan.

'You see – the shaft is hollow. The gold was in the tube inside the handle, and when he stirred, the heat melted the gold, and it slid out and into the lead in the bowl. Then as he continued to stir, it moved to the bottom of the bowl.'

Bahram looked at Khalid, shocked, and saw that it was true. His father in law's face was white, and he was no longer sweating. Already a dead man.

The Khan roared wordlessly, then leaped at Khalid and struck him down with the book he had been given. He beat him with the book, and Khalid did not resist.

'Take him!' Sayyed Abdul Aziz shouted at his soldiers. They picked up Khalid by the arms and dragged him through the dust, not allowing him to get to his feet, and threw him over a camel. In a minute they were all gone from the compound, leaving the air filled with smoke and dust and echoing shouts.