Today we made it to the summit of the canal, through many locks in intermittent rain. It’s so nice to have a large crew, it makes working the locks a lot more fun. On the way we stopped at Crofton pumping station. So far most of the locks were fed with water from the River Kennet, it doesn’t get up this high, so water has to be pumped up to the highest section of the canal. Though that’s mostly done by electric pumps these days, the original steam engines that did the job are still there, and have been restored to working order. We lucked out. They are running them this weekend! One of them is over 200 years old and was supplied by James Watt himself, along with his partner Matthew Boulton.

Watt was the inventor, and Boulton was the venture capitalist. Boulton made his fortune mass producing silverware. He became Watt’s partner by accident when he was offered a share in Watt’s patent by Watt’s previous partner, in payment for a debt. Boulton provided the business flair and drive to go along with Watt’s mechanical genius, and he and Watt installed hundreds of steam engines in mines and factories. This is the only one that is still working in its original location. Incidentally, if you remember the old pre-decimalization British penny coins, Boulton originated those, too, but that’s another story.

In 1812, when this engine was built, Napoleon was invading Russia, Charles Dickens was born, and the Luddites were smashing mechanical weaving equipment. We all make mistakes, but invading Russia was a biggie. The jury is still out on the Luddites.

“OK”, you say, “Great introduction Andrew, now show us a picture of the steam engine.” I can’t. It’s too big. It occupies half of a three story building, with shafts and pistons poking through the floors. So here’s some bits of it. It takes more than a ton of coal a day to raise steam on the pumping station, all shoveled by hand into the boiler.

The steam from the boiler is only about 20psi (one and a third atmosphere) which is not very much compared with later engines, so the piston has to be really big to use it.

The piston going up and down makes a beam rock, and the other end of the beam runs the water pump.

That’s a vast oversimplification, as there is a four bar linkage in there that converts the pure vertical motion of the piston into the arc of a circle that the end of the beam moves in, that is a remarkable work of engineering in itself.

Of course, at the end of a stroke the direction of the piston must reverse, this is done by a system of mechanical controls that you also get to see in motion.

There is no way you could get within poking distance of that sort of machinery in the US. It would be behind plate glass, or you would have to view from a safe ten feet away. Actually, you can’t get ten feet away, because there is another bloody great steam engine in the other half of the building, this one a comparative youngster at 170 years old.

We are now 457 feet above sea level. It’s all downhill from here to Bath.

Then back up again, but we’re not talking about that yet.