'The safety pin,' he had announced. 'The torpedo is now armed, with fifty-four pounds of guncotton ready to explode the moment this projecting bolt is depressed by impact. The sort of impact you would get if it hit the side of a ship.'

Macintyre had tugged gently on a rope to line it up with the outline of an old hulk, a fishing boat that had run ashore many years before and been abandoned. He thought it would be a nice demonstration of his invention's power if this could be reduced to matchwood. When all was ready he took a deep breath, and pulled out the pin which allowed the air from the pressurised tank to flow down the pipes into the small turbine which turned the propeller.

This is where Bartoli's interventions came into play. At first, all went well; the propeller whirred, the machine began to move. But it quickly became apparent that, instead of heading in a dead straight line towards the hulk, it was veering very sharply off to the right, and only at about two miles an hour, rising and falling in the water like a demented porpoise. Already, the bankers were exchanging glances, and Macintyre was looking distressed.

Worse was to come. For it became obvious – something Bartoli had not intended at all – that the machine was describing an erratic circle in the water, so that its course would bring it back, more or less, to where it had started. That it was going to hit the boat, with that much-advertised fifty-four pounds of guncotton ready to explode on impact.

Something like panic had set in, everyone trying to figure out where the machine would hit and get as far away from it as possible. Only Macintyre stood there, immediately above the likely spot, as it lurched towards them.

Then, the motor stopped. Instead of the supposed fourteen hundred yards range, it gurgled to a halt after little more than three hundred, which was just as well, as another five yards and it would have blown the boat, and all in it, to kingdom come. There was a moment's silence, then, with a loud and apologetic burp, it sank.

Fortunately, they were in a fairly deep part of the lagoon, as the torpedo went down head first and exploded the moment it touched the bottom. I had never witnessed such a thing, but apparently fifty-four pounds of explosive makes a tremendous bang. It must do, if it is enough to sink a battleship. There was a muffled roar, an eruption of water some forty feet high, a small tidal wave which almost turned the boat over, and everyone got soaked. The demonstration had come to its spectacular conclusion.

Macintyre's backers were unimpressed, to say the least. They had seen the machine fail completely, they had been soaked and frightened out of their wits. The journey back to Venice took place in total silence.

I looked at Bartoli as he finished. 'What did you do to it?' I asked.

'Very little, really,' he replied, in a tone which did little to disguise his feelings of guilt. 'Just a turn of a screw here and a mismatched connection there. A bit of weighting to put the gyroscope out. Little things, of the sort Macintyre wouldn't notice.'

'He certainly won't now,' I said, 'as it's in little pieces. What about the bankers?'

He shrugged. 'They didn't say a word. Not even goodbye. They just marched off the boat when it docked and walked away. Macintyre tried to talk to them, say it worked fine, really. But they didn't want to listen. Listen, I have to go back to him. He is really upset and he's drinking. He could do something very foolish if he's not watched. Are you sure we did the right thing?'

'Absolutely sure,' I said robustly. 'I fully expect a letter from Ambrosian very soon. In their view, the only way to recover their money will be to persuade me to buy the debt before I realise that the machine is useless. News spreads fast in this city, so they will have to move quickly or it will be too late. If I hear something, I will let you know immediately. Meanwhile, go and find Macintyre, tell him not to despair, that all will be well. Tell him whatever you want, but cheer him up.'

I was right. When I returned home, there was a letter awaiting me. In the florid, formal Italian normal for such letters, it informed the illustrious signore – me – that my proposal concerning the Macintyre project had now been put to the board, and had been decided upon favourably. If I wished to pursue the matter, then I should indicate that I wished to purchase the credit note.

There was also a handwritten note from Ambrosian accompanying this formal missive. He had worked hard on this matter on my behalf, he said, and had only persuaded the board to agree because one member was away. He was due to return tomorrow and would undoubtedly try to overturn the decision when he heard about it. If at all possible, then I should come and conclude the deal as quickly as possible, otherwise it would be too late.

I loved the audacity of the man, the smooth and reasonable way he managed to tell such enormous lies. A fine fellow indeed – astute, calculating, ruthless, mendacious; it cheered me up considerably.

I hurried back to the bank as swiftly as I could, then dallied a little, in order to make him a little more nervous. At six-twenty in the evening, just ten minutes before it was about to close, I presented myself and asked to see Signor Ambrosian.

You may think that I should have attended to other matters. Perhaps I should have gone myself to tell Macintyre what was happening; should have gone to see Cort. I agree. I should have done both of these. And if I did not, it was not because I did not consider both of them. But I believed Bartoli could take care of Macintyre and as for Cort – what can I say? I was not yet ready to face him.

'I am so glad we can reach agreement on this matter,' I said once I had sat down and accepted the offer of a glass of cold wine.

'As am I,' he replied with a warm smile. 'Although, as I said in my letter, it was not easy to accomplish. But I felt that really we did not want to get involved in the business of setting up factories. However excellent Mr Macintyre's machine, any profits that might accrue become greatly postponed. And we Venetians no longer do this sort of thing; we prefer to leave it to the more enterprising English, and pursue lesser, short-term profits ourselves. It is no doubt why England has an empire and Venice has lost hers.'

'That may be so. Certainly I think you do not have a ready supply of the necessary engineers, managers and skilled workers that would allow you to set up such an establishment here. Such people can be found more easily in England.'

'You will manufacture there?'

'I think so. The most obvious customer is the Royal Navy. If it will buy, every other navy in the world will have to follow suit. And it is a patriotic organisation. They will not buy foreign wares if they can avoid it.'

'In that case, I will watch your progress with the greatest interest,' he said. 'Now, perhaps we might get the business dealt with? Then I would be very happy to invite you to dinner.'

'That is kind,' I replied. 'But I feel I should go and find Mr Macintyre, and tell him the news. I was just about to go and see him this afternoon, in fact, when your letter arrived.'

Ambrosian ordered a sheaf of papers on his desk, turned them round and proffered them to me. 'Then you will no doubt have a great deal to discuss when you see him. Perhaps you wish to read this? I am assuming you can read Italian? If not, I will gladly call someone in to translate.'

I said I could manage, and spent twenty minutes sipping my wine, and struggling through to make sure there was nothing untoward. The language was legal, but essentially clear, and why should there be any hidden catches? It was a deed of sale drawn up in a hurry, and the object was to get rid of a useless property as quickly and cleanly and as absolutely as possible.