As I was cycling into work this morning my mind started to wander. I looked down at the bike beneath me and had a weird sensation of 'solidness'. It's hard to put this into words, but I'm going to try. There I was, doing about 15miles an hour, balanced on a device which itself was sitting on two patches of rubber a few centimetres across. It felt quite improbable, surely this thing must topple to one side - yet it doesn't. It must be this reasonable expectation which makes it hard to learn to ride a bike in the first place - the brain is convinced it can't work.
Despite going along, thinking about the precariousness of my situation, I didn't begin to wobble. It is always a danger that if you start to think about something which you normally do instinctively, you begin not to be able to do it!
This feeling of 'solidness' might seem an odd thought to have (especially once you know that bikes are more stable when moving due to dynamic effects), but stop to think about a world without bicycles, and then think of someone conceiving of this device: "I know, I'll invent a two wheeled means of personal transportation that people can balance on, propelling themselves by means of a crank mechanism attached to the back wheel" - it's just a phenomenal leap. Admittedly the penny-farthing looks very different to modern bikes, but that's evolution, not revolution. The imaginative leap to conceive that everyday people, without circus training, could balance without any difficulty on a two wheeled vehicle is just astounding - and then to go and make it happen....
Of course, this thought was founded on unsound principles. The bicycle did not emerge fully formed, the penny-farthing wasn't revolution. It was preceded by Baron Karl Drais von Sauerbronn's 'running machine' (essentially a bike without pedals) which people propelled with their feet. People would have found by trial and error that they could balance on the machine (even if the designer intended that their feet would be on the ground) - and then, this leads by an evolutionary process into giving the wheels some motive push with the feet (pedals).
Once you have pedals, you can then gain speed with bigger wheels (gearing) and then you have a penny farthing. With the addition of a chain we allows cogs and smaller wheels (modern bike). In the early days, the recumbent bicycle was another path being explored, but was ruled out of races as the advantage was too great - and so they're rare today (but seem to be getting more available again).
So, there I was, cycling along, relishing in the feeling of stability - and thinking about all the engineering that made it possible.
Then, my wonder at the engineering marvel speeding me along the road was broken by a roadside bunny who hadn't heard me coming and got spooked as I went past.
I liked my commute today.