July 21: Science Museum

It's still hot today, but not as brutal.  I decided to go to the Science Museum.  The web says it's air-conditioned but not to hope for really cool conditions.  That turned out to be accurate; it was a little warm and stuffy, but bearable.  And the contents were extremely interesting.  Much of it was hard to photograph, so I've only got a few pictures, but I saw quite a lot. 

First I went to a special exhibit about Leonardo da Vinci.  Many people think of him as an artist and forget that he was also a brilliant inventor and visionary.  He left many sketches of ideas that couldn't be implemented with the technology of his time but were extremely interesting. They were detailed, but some also left quite a bit to the imagination.  This exhibit displayed reproductions many of these sketches plus 20th century wooden models of how the ideas might have been realised.  I didn't get any photos of these, but they were fascinating.  The models included a "flying machine" (kind of like a helicoptor), ideas about how to build walls around a castle to maximize its resistance to attack, and a primitive sort of diving suit to allow people to repair the hulls of ships underwater without having to haul the ship out of the water.  The exhibit also included a lot of really interesting information about Leonardo's life and what was going on in the world while he was creating all of these ideas.

After that, I went searching for Babbage's Difference Engine.  This is a famous and important historical relic of the early days of my profession (Computer Science).  And it just happens that there was a documentary on TV about Babbage shortly before our trip, so David and I were eager to see it.  David went to the Science museum on his one full day in London -- while I was applying for my return visa -- and today I went to see it for myself.

I say that I "went searching" for the engine because it really was a search.  This museum was beautiful and full of fascinating objects, but it wasn't terribly easy to find things!  On the plus side, there were many museum employees who were very kind about giving directions for finding specific objects.  The trouble is that it can be hard to describe exactly where something is in an enormous museum and I had to ask several times.  It got frustrating, but the search was worth it.

To add to the confusion, they actually have two difference engines, which I hadn't realised at first.  There's a very long, complicated history to all this, which you can find here if you're interested.  In brief, here is a model created by Babbage in the 1850s.  It's just a section of a complete Difference Engine:

You can't tell from the picture, but this above model is only about two feet high.

Babbage wasn't able to complete an entire Difference Engine in his lifetime. In the late 20-th century, however, the Science Museum decided to build a Difference Engine to celebrate the 200th anniversary of Babbage's birth (in 1991).  It is complete and actually works:

This successful version is a little taller than me.

Seeing those two objects is kind of like being a pilot or an aeronautics engineer and seeing the Wright Brothers airplane!

Nearby I stumbled upon another artifact related to Computing:

This is a mechanical Jacquard loom, used to weave cloth with complicated patterns in it.  The threads and fabric are near the bottom of the picture.  What you see on top is a series of cards with holes punched into them.  These cards encoded specific patterns for the machine to follow while weaving.  These cards were the inspiration for the punched cards used in the earlier days of Computing.  I am old enough to have used punched cards as an undergraduate.

Besides these Computing artifacts, I saw many other interesting things.  There was a big exhibit about the history of communication, including the development of the telegraph and telephone and transatlantic cables.  Other exhibits included transportation, agriculture, and space exploration.  Most of these things didn't lend themselves to photography, but were quite interesting in person.  I wandered happily for most of the day and learned a lot.

And on my way back to my hotel at the end of the day, I happened to stumble upon another science-related thing near Paddington Station.  It was just a small plaque on the wall of a building near a hospital:

Pretty cool!  Especially interesting to me because just two days ago in Kensington Palace, I learned that William III died of complications from a broken collarbone.  One of the visitors was expressing surprise that someone could die from a broken bone and one of the "explainers" said a bad fracture can lead to infections, which could be quite lethal without antibiotics.