'He is not even one of the people of the book,' one of the qadi said indignantly.

'We have many books in Tibet,' Iwang said calmly, as if he had misunderstood.

The qadi were offended. 'What is your religion?'

'I am Buddhist.'

'So you don't believe in Allah, you don't pray to Allah.'

Iwang did not reply.

'Buddhists are polytheists,' one of them said. 'Like the pagans Mohammed converted in Arabia.'

Bahram stepped before them. Thereis no compulsion in religion",' he recited hotly. Toyou your religion, to me my religion." That's what the Quran tells us!'

The visitors stared at him coldly.

'Are you not Muslim?' one said.

'I certainly am! You would know it if you knew the Sher Dor mosque! I've never seen you there – where do you pray on Friday?'

'Tilla Karia Mosque,' the qadi said, angry now.

This was interesting, as the Tilla Karia Madressa was the centre for the Shiite study group, which was opposed to Nadir.

"'Al kufou millatun wahida",' one of them said; a counter quote, as theologians called it. Unbelief is one religion.

'Only digaraz can make complaint to the law,' Bahram snapped back. Digaraz were those who spoke without grudge or malice, disinterested Muslims. 'You don't qualify.'

'Neither do you, young man.'

'You come here! Who sent you? You challenge the law of the aman, who gives you the right? Get out of here! You have no idea what this man does for Samarqand! You attack Sayyed Abdul himself here, you attack Islam itself! Get out!'

The qadis did not move, but something in their gazes had grown more guarded. Their leader said, 'Next spring we will talk again,' with a glance at Iwang's aman. With a wave of his hand that was just like the Khan's, he led the others out and down the narrow passage of the bazaar.

For a long while the two friends stood silently in the shop, awkward with each other.

Finally Iwang sighed. 'Did not Mohammed set laws concerning the way men should be treated in Dar al Islam?'

'God set them. Mohammed only transmitted them.'

'All free men equal before the law. Women, children, slaves and unbelievers less under the law.'

'Equal beings, but they all have their particular rights, protected by law.'

'But not as many rights as those of Muslim free men.'

'They are not as strong, so their rights are not so burdensome. They are all people to be protected by Muslim free men, upholding God's laws.'

Iwang pursed his lips. Finally he said, 'God is the force moving in everything. The shapes things take when they move.'

'God is love moving through all,' Bahram agreed. 'The sufis say this.'

Iwang nodded. 'God is a mathematician. A very great and subtle mathematician. As our bodies are to the crude furnaces and stills of your compound, so God's mathematics is to our mathematics.'

'So you agree there is a god? I thought Buddha denied there was any god.'

'I don't know. I suppose some Buddhists might say not. Being springs out of the Void. I don't know, myself. If there is only the Void enveloping all we see, where did the mathematics come from? it seems to me it could be the result of something thinking.'

Bahram was surprised to bear Iwang say this. And he could not be quite sure how sincere Iwang was, given what had just happened with the qadis from Tilla Karia. Although it made sense, in that it was obviously impossible that such an intricate and glorious thing as the world could have come to pass without some very great and loving god to make it.

'You should come to the sufi fellowship, and listen to what my teacher there says,' Bahram finally said, smiling at the thought of the big Tibetan in their group. Although their teacher would probably like it.

Bahram returned to the compound by way of the western caravanserai, where the Hindu traders were camped in their smell of incense and milktea. Bahram completed the other business he had there, buying scents and bags of calcinated minerals for Khalid, and then when he saw Dol, an acquaintance from Ladakh, he joined him and sat with him and drank tea for a while, then rakshi, looking over the trader's pallets of spices and small bronze figurines. Bahram gestured at the detailed little statues. 'Are these your gods?'

Dol looked at him, surprised and amused. 'Some are gods, yes. This is Shiva – this Kali, the destroyer – this Ganesh.'

'An elephant god?'

'This is how we picture him. They have other forms.'

'But an elephant?'

'Have you ever seen an elephant?'

'No.'

'They're impressive.'

'I know they're big.'

'It's more than that.'

Bahram sipped his tea. 'I think Iwang might convert to Islam.'

'Trouble with his aman?'

Dol laughed at Bahram's expression, urged him to drink from the jar of rakshi.

Bahram obliged him, then persisted. 'Do you think it's possible to change religions?'

'Many people have.'

'Could you? Could you say, There is only one god?' Gesturing at the figurines.

Dol smiled. 'They are all aspects of Brahman, you know. Behind all, the great God Brahman, all one in him.'

'So Iwang could be like that too. He might already believe in the one great god, the God of Gods.'

'He could. God manifests in different ways to different people.'

Bahram sighed.

Bad Air

He had just gone inside the compound gate, and was on his way to tell Khalid about the incident at Iwang's, when the door of the chemical shed burst open and men crashed out, chased by a shouting Khalid and a dense cloud of yellow smoke. Bahram turned and ran for the house, intending to grab Esmerine and the children, but they were out and running already, and he followed them through the main gate, everyone shrieking and then, as the cloud descended on them, dropping to the ground and crawling away like rats, coughing and hacking and spitting and crying. They rolled down the hill, throats and eyes burning, lungs aching from the caustic stink of the poisonous yellow cloud. Most of them followed Khalid's lead and plunged their heads into the river, emerging only to puff shallow breaths, and then dunk themselves again. When the cloud had dispersed and he had recovered a little, Khalid began to curse.

'What was it?' Bahram said, coughing still.

'A crucible of acid exploded. We were testing it.'

'For what?'

Khalid didn't answer. Slowly the caustic burn of their delicate membranes cooled. The wet and unhappy crew straggled back into the compound. Khalid set some of the men to clean up the shed, and Bahram went with him into his study, where he changed his clothes and washed, then wrote in his big book notes, presumably about the failed demonstration.

Except it had not been completely a failure, or so Bahram began to gather from Khalid's muttering.

'What were you trying to do?'

Khalid did not answer directly. 'It seems certain to me that there are different kinds of air,' he said instead. 'Different constituents, perhaps, as in metals. Only all invisible to the eye. We smell the differences, sometimes. And some can kill, as at the bottom of wells. It isn't an absence of air, in those cases, but a bad kind of air, or part of air. The heaviest no doubt. And different distillations, different burnings… you can suppress or stoke a fire… Anyway, I thought that sal ammoniac and saltpetre and sulphur mixed, would make a different air. And it did, too, but too much of it, too fast. Like an explosion. And clearly a poison.' He coughed uncomfortably. 'It is like the Chinese alchemists' recipe for wan-jen ti, which Iwang says means "killer of myriads".. I supposed I could show Nadir this reaction, and propose it as a weapon. You could perhaps kill a whole army with it.'

They regarded the thought silently.

'Well,' Bahram said, 'it might help him keep his own position more secure with the Khan.'