In these great halls of production there are marvels to behold. Go to the great ironworks of Sheffield and see the forges, or the new steel presses that have sprung up around Birmingham, see the gigantic monsters that can crush and bend many tons of metal in one swipe of a press, machines so vast that it would seem arrogant even to have dreamed of them. Or to the vast turbine halls that turn water into steam and then electricity in rooms so big clouds can form in their upper levels.

And, in all of these, look at the men who work there. Are the floors clean, the men well dressed and proud of their appearance? Do they work with willingness, is there a sense of purpose in their eyes? Do the employers seek out the best, or the cheapest? Five minutes is enough to tell me if an enterprise will rise or fall, prosper or diminish. It is all in the eyes of labour.

Macintyre's operation was on a much smaller scale, but the principles were the same. And the signs were good. Although ramshackle on the outside, inside the shed was spotless. All the tools were neatly ordered, the floors swept, the benches well organised. The brass on the instruments gleamed, the steel was well oiled. Each machine was cared for and well situated. It had all been thought through. And those he employed went about their business with a quiet resolve, talking rarely and then quietly. They knew what they were doing.

'I found them,' he said when I asked, 'here and there. Giacomo over there was supposed to be a boat-builder, but his father died and he could find no master. I noticed him carving a piece of driftwood to sell to passers-by. He had such fine control of his hands I knew he was intelligent. He made himself indispensable inside a week. He can set up a machine faster and more accurately than any man I have come across. If he had the technical knowledge to go with his skill, he would be formidable.'

He gestured to another. 'Luigi is another. He has more training; I found him in an artist's studio being trained as a restorer. He has no talent for painting, so he had not much of a career ahead of him. His talent is for drawing, he is an immensely skilled draughtsman, and can take my sketches and turn them into plans. He and Giacomo can then turn them into precise settings on the machinery.'

'And that one?'

'Ah, Signor Bartoli. A man of all tasks. He is the general, all-purpose worker. He helps one or other of the two and knows how to follow his instructions perfectly. If something needs doing, he will do it, faster and better than you hoped.'

'You are more fortunate than Mr Cort in your choice of labour, then.'

'I am a better judge of men, more like. And more able to command them. When I see Mr Cort at work, I feel like grabbing him by the neck and giving him a good shake.'

He snorted in disgust, in a way which spoke volumes. Macintyre was thinking what he would have accomplished if he had had the advantages of Cort's birth and opportunities. There are many such men in our industries; I have made it my business to find them and give them their chance.

'Yet you assisted him the other week?'

'Oh, that. That was nothing. It took no time at all, and I was getting heartily sick of listening to his despair. At least he has decided to take my advice. He is even prepared to contemplate blowing the column out with explosives. There may be a man of sense in there after all. His trouble is that he has been trained to do things the way they are done, not the way they should be done.'

'Are you going to tell me what that great thing is over there?' I called out to him. He had wandered over to Luigi, and was discussing some problem, my presence perfectly forgotten. A strange way of talking he had, as well. A sort of pidgin English with smatterings of Italian thrown in. It was the lingua franca of the workshop, where conversations were conducted half in words, half in gestures and mime. All the technical words were in English, not surprisingly perhaps as none of the three Italians knew any of them before they came to Macintyre, and he did not know the Italian equivalents, even when they existed. The grammar was Italian, and the rest was a mixture of the two, with a lot of grunting thrown in to fill up space.

I had to wait for an answer; whatever the problem was it took some sorting and ended with Macintyre on his knees before the machine – some sort of drill, as far as I could discern – like a penitent at prayer, slowly twisting knobs to make fine adjustments, measuring distances with calipers, repeating the operation several times before an outburst of grunting suggested the problem was resolved.

'What was that?' he asked when he returned to my side.

'Your plumbing.'

'Ha!' He turned and led the way back to the lone machine lying clamped on a solitary workbench. 'What do you think it is?'

I looked carefully at the machine before me. It was a thing of some elegance, essentially a steel tube with wing-like projections along its length, tapering at the back and ending with a small three-winged propeller in shiny brass. At the other end, it stopped abruptly and open to the air, but a little way away was a continuation which obviously bolted on to the end to give a rounded shape.

'It obviously is designed to go through the water,' I said. I walked around and peered into the nose of the machine. It was empty. 'And this clearly holds something. Most of its length is taken up with machinery, which I take to be the engine, although there is no funnel, and no boiler. This empty piece must hold the cargo.' I shook my head. 'It looks a bit like a very big shell with a propeller attached.'

Macintyre laughed. 'Very good! Very good! A shell with a propeller. That is precisely what it is. A torpedo, to be precise.'

I was puzzled. A torpedo, I knew, was a long pole pushed from the front of a ship to impale an opponent, then explode. Hardly useful in the days of ironclads and ten-inch guns.

'Of course,' he continued, 'I merely borrow the word as I could think of nothing better. This is an automobile torpedo. A charge of explosive there,' he pointed at the nose, 'and an engine capable of propelling it in a straight line there. Aim it at the opposing ship, set it off and that's that.'

'So the front will be full of gunpowder.'

'Oh no. Gunpowder is too susceptible to damp. And something which goes underneath the surface of the water is liable to get wet, however well it is made. So I will use guncotton. And, of course I can make it myself; one part cotton wool in fifteen parts of sulphuric and nitric acids. Then you wash it, dry it. Look.'

He gestured to a series of boxes in the corner that rested on top of several vats.

'That's the guncotton?'

'Yes. Over the past few months I've made several hundredweight of the stuff.'

'Isn't it dangerous to have it lying around?'

'No, no. It's quite safe, if it's prepared properly. If it's not cleaned and dried as it should be, then it can easily go off all on its own. But this is perfectly safe. To make it explode, it will have to be compressed, then set off with a detonator made of mercuric fulminate. At the moment you could jump up and down on it all day and come to no harm. That's the dangerous stuff over there.' He pointed to another corner.

'What's that?'

'Gunpowder. I bought it before I realised it wouldn't do. It's useless now; I'm going to use it on Cort's pillar, if he can make up his mind what he wants.'

'So the explosive is in the front, it hits the ship and – bang.'

'Bang. Precisely,' he said approvingly.

'What size bang? I mean, how much explosive will you need to sink a battleship?'

'That will be determined by experiments.'

'You're going to fire off torpedoes at passing battleships until one sinks?'

'I don't think that will be necessary,' he said, with the air of one who would have loved nothing more. 'Detonating explosives against plates of armour will do.'