In His Own Words: Adam Hart-Davis on James Watt and our World at the Science Museum

Interview by Ben Miller | 23 March 2011
A photo of a man in a suit talking into a camera
In His Own Words…Broadcaster and history lover Adam Hart-Davis on James Watt and Our World at the Science Museum…

“James Watt was an extraordinary inventor, but please do not get the idea that he invented the steam engine. The first patent for a steam engine was taken out in 1698, which was the year Watt's father was born. It had been running for at least 50 years before he got his hands on it. But what’s really exciting is the one he got his hands on, just before Christmas in 1764, which we’ve got here.

“One Sunday morning in May 1765, he went for a walk on Glasgow Green. It’s a very flat, boring bit of grass in the middle of Glasgow. In the middle of it there’s a statue of someone like Nelson – anyway, Watt was walking there one Sunday morning and he had this flash of inspiration. It was one of those Eureka moments, and he said he hadn’t walked further than the golfhouse when the whole thing had been arranged in his mind.

“What he invented was actually a very boring metal tube – it doesn’t look very exciting, and when you say ‘it’s a separate condenser’ people say ‘well, what is that?’ But that was what made all the difference – it increased the efficiency of the steam engine by a factor of three or four.

A photo of a long grey cylinder against a black background
Watt's condenser revolutionised the capabilities of steam engines© Science Museum, London
“It made it possible to use steam engines not only to pump water out of the mines in Cornwall. They didn’t have coal in Cornwall so they couldn’t afford to run new engines, but they could afford to run Watt engines.

“They went on to use it to drive machinery, and that’s when the Industrial Revolution really took off, when they started spinning and weaving cotton and milling and grinding. He wasn’t the only person responsible, because after him came high-pressure steam and so forth – it all developed – but it was Watt who started it all.

“At the same time he was a great scientist – he was the person who told the world that the formula for water is H2O. It was actually worked out here in London, down in…what’s that pond in South London? Clapham Common. Henry Cavendish, who was a brilliant scientist, used to go down there and make explosions with hydrogen and oxygen.

“We were doing that with balloons on Clapham Common ourselves, and a whole load of police cars suddenly lined up along the road. We began to worry, then we realised there was actually a greasy spoon there and they’d come for their lunch. When we let off our explosions they all turned away and pretended they couldn’t hear them.

“What is wonderful about his workshop is that not only are there superb machines there, but the entire walls are lined with holes full of junk. Some of these things come from when he moved down from Glasgow [to Birmingham] in 1774, and they were still there when he died 40 years later. It was mainly his hobby workshop when he was retired.

“About 20 years ago we did a series called Local Heroes in which I rode around on a bike talking about industrial heroes. We did about 250 of them, and Watt was one of them. I love him dearly and it's easy for me to talk about because I know all his stories.

“It’s very odd – I can’t remember names or faces, but I remember these stories. Watt was an absolute genius.”

  • The permanent display opens at the Science Museum today (March 23 2011)

Watch Adam Davis-Hart introduce Watt's condenser:

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