I remember it well; there was a total silence, broken only by the sound of people, faintly heard, pushing barrows in the street below. She had been lying on the bed, I next to her. Suddenly there was a distance between us; she curled away, and I sat up, and the gap became immense and unbridgeable.

'You are like the others,' she said, softly but coldly. 'You want to get rid of me, you've found your excuses. I've felt it growing in you; I've been expecting it, just wondering what reasons you were going to give yourself. Why not just say it directly? Why pretend it is for my good?'

'What others? Drennan, for example?' I asked, still remarkably calm. She laughed.

'Why are you laughing?'

She shrugged.

'Did you give your husband opium the night of the séance? Prepare the Marchesa by giving her information you knew would come out in her trance?'

A little smile of satisfaction, but no answer.

I expected some story I could believe, something that reassured me and made me think I had been foolish ever to doubt her. But she gave me nothing.

'You want to leave me,' she said. 'I know you do. Why not just say so? Holiday over, so back to your little wife in England?'

She stopped, looked at me for a second, then said, coyly and softly: 'Don't you think she deserves to know how you've been spending your time?'

'What did you say?'

'Dear Mrs Stone, I was your husband's mistress until he became bored with me. He seduced me on a beach while you were sitting at home. I'm . . .'

'Be quiet!'

'You don't really think you can leave me here and go back to England as if this never happened? Do you really think that? I will never leave you. I will follow you to your dying day. Are you ashamed? I'm not. I don't care who knows about you, or what they think of me.'

'I said, enough!'

'Why? Whatever's the matter? Are you upset? Oh!' she said in mock sympathy, 'you feel deceived! How sad! I'd forgotten. You're the only one who can deceive people, and tell lies.'

'I think I should leave. It would be better if I did not see you again.'

'For you, perhaps. Not for me.'

I walked to the door and she began to pull on her clothes.

'Do you know what I'm going to do now?' she said with a smile.

'What?'

'I think it's time William knew the truth about everything, don't you? I'm looking forward to telling him about the time we made love while he was waiting outside. How you particularly enjoyed that. It might finish him off for good, don't you think? And once I'm free of the boy as well, it will be your turn.' She looked at me with such a glance that I felt a shiver run down my spine.

'You will do nothing at all.'

'And you are going to stop me . . . how exactly?'

I was silent.

'How much?'

She was the one who said it, not me. It was a mistake, a complete miscalculation. She brought everything back into an area I could understand. Until then she had been in charge, I merely responding.

'And what does that mean?'

'A word to my husband, a letter to your wife. How much?'

'And what do you suggest?'

'I think that £100 would be about right.'

'A hundred pounds?'

'A year.'

And then I laughed out loud. 'Do you know, until you said that, a little bit of me still felt sorry for you? Do you really think I am going to keep you for the rest of your life? I have done nothing you have not done yourself. I owe you no more than you owe me. Let me tell you how much your silence is worth. Nothing. Not a penny. You will do nothing, and I will give you nothing in return. That is fair payment on both sides. Otherwise you will regret having threatened me. More than anything, you will regret that.'

She smiled. 'We shall see.'

I was shaking when I left, walking fast and trying to get away from that accursed room as quickly as possible. The change, from complicity to antagonism, love to hatred had been so swift, so unforeseen, that I was trembling with shock. How could it have happened? I have been so mistaken? How could I have made such a terrible error? How did I not see more clearly, I, who prided myself on my judgement? It was a lesson for the future, but at that moment I was simply too stunned to think clearly.

What stuck most forcibly in my mind was her lack of emotion. Had she raged and screamed, behaved like some monster or hysteric, had she attacked me, or fallen on the floor sobbing, it would have been more understandable. But she behaved like a man of affairs; she'd done her best, it hadn't worked, it was time to cut her losses. She behaved like me, in fact; and it was I who was shocked, trembling, overcome with emotion. Only her clumsy attempt at blackmail had saved me. Had she said nothing at all, I might well have offered her something, but I have never liked to be threatened. That changed everything.

But I remembered the look in her eyes, her threats. Was she capable of carrying them out? I thought she was. In fact, I was certain of it. That did not bother me personally. At the most it would cause a temporary embarrassment – tiresome no doubt, but nothing that could not be shrugged off soon enough. I had no fear of anything she might do to me.

Cort was another matter; and there I did not know what to do. I had justified my behaviour with the thought that his mistreatment of her had been so monstrous that his punishment was deserved. I had now seen another, dark side of her, one I did not wish to be close to. But those marks, those weals and bruises, had been real. Merely because I now recoiled from Louise did not mean I felt so much more sympathetic to her husband. Perhaps they deserved each other?

So I did nothing, and constructed good reasons for my passivity. I did not excuse myself, though; please do not think that. I did not blame anyone, say that it was the influence of Venice or of strange madmen, or the light or the sea which had forced me to behave in such a reckless fashion. It was I, and I alone, who was responsible, and I was very lucky to have escaped so lightly. Had it not been for the hints and warnings of Marangoni and Drennan – and of Signor Casanova, whose words had, perhaps, the greatest effect of all – I could easily have been swept away by the elation of passion, sworn to love her forever, taken her for my own. Had I done so, I would have lived with my error, which soon enough would have become clear, of that I was sure.

It took a long time to calm myself, walking through the back streets, staring out over the lagoon, all sights which once pleased me, and I now began to find humiliating. I was waking up from my reverie fast. It was time to move; I wanted to leave Venice quickly. My dream world with Louise – what I had thought she was, at least – and of Venice were the same thing, and it was time to shake free of both. Neither had any more power over my mind. This decision came over me quickly and unconsciously. From a state where I was not even considering the question a short while previously, I began to think of packing my bags, making arrangements to travel. It was time to be off.

Bartoli found me in a quiet, determined mood when he walked into the café where we had agreed to meet, and it took an effort on my part to pay proper attention to his story. But it did me good to do so; the more we talked, the more Louise faded from my mind, became a problem to be contained and managed, nothing more. He also needed attention, for he was having very severe second thoughts about what he had just done. Macintyre was distraught, half-crazed with disappointment, inconsolable.

As he told it, all had been as before; the boat had sailed slowly out to the northern part of the lagoon, where they could be fairly sure there would be no prying eyes. The torpedo had been prepared and lowered over the side once more. The only difference this time was that Macintyre had very carefully removed a pin from the front end of the torpedo and held it up for all to see.