‘Jackson Street,’ said Collis. ‘Mr Kwang’s, if you know it.’

‘Oh, yes, sir,’ the driver told him, clicking encouragement to his horse. ‘I know it all right.’

Mr Kwang was working on his accounts. He was sitting crosslegged in a dim room, lit only by a Chinese oil lamp with a blue-and-white shade of the thinnest frosted glass. He was writing on sheets of rice paper with a bamboo brush, and every now and then his fingers would fly at a large ebony-and-ivory abacus which stood beside him, making the beads rattle across the wires like a volley of musketry.

Collis was shown in, and he stood without speaking for a while as Mr Kwang completed a column of figures. Then Mr Kwang looked up at him and said, ‘Mr Edmonds. Please make yourself comfortable.’

‘I hope I’m not interrupting,’ said Collis. ‘I didn’t have time to make an appointment.’

Mr Kwang set his brush down in a small porcelain dish of ink. ‘You are a friend of the Chinese, Mr Edmonds. You are welcome at any time.’

Collis took off his hat and sat down on the floor. ‘You’ve already done me one favour, Mr Kwang.’

Mr Kwang’s face was expressionless. ‘Investment in the future of the Chinese people is not a favour, Mr Edmonds. By helping you in your personal difficulties, I hope I have assured the employment of Chinese labour on the transcontinental railroad.’

‘Yes,’ he said solemnly, ‘I believe you have.’

‘You would like tea?’ asked Mr Kwang.

‘No, thanks. I don’t have the time. I came for something quite specific.’

‘Ah,’ said Mr Kwang, nodding. ‘Is it money you want? I regret I can’t help you there. All of my money is tied up in property, and in girls.’

‘No, not money,’ said Collis. ‘Opium.’

‘Opium? You surprise me. You don’t mean to take it yourself?’

Collis shook his head. ‘Oh, no. Nothing like that. I just want enough to put someone to sleep for an hour or two. Enough so the person doesn’t really realise what’s going on.’

Mr Kwang looked down at his accounts. ‘You have something very devious in mind, Mr Edmonds. Something that involves the participation of somebody who, under normal circumstances, would not be willing to help you.’

‘You’re an astute man, Mr Kwang.’

‘I am the leader of the On Leong Tong, Mr Edmonds.’

Collis cleared his throat. ‘Then you can help me?’

‘Possibly. But the opium will have to be taken as a tincture. You can’t persuade anybody to smoke it against his will.’

‘I’ll pay for it,’ said Collis. ‘I didn’t come here expecting something for nothing.’

Mr Kwang regarded him for a moment with that smooth, impenetrable face. Then he clapped his hands, once, and his young hummingbird appeared, in a dress of turquoise silk. He spoke to her, quickly, in Hokkien. She nodded and went shuffling off.