Climbing Big Ben

Last week Zee and I took a glorious day off work and climbed Big Ben. Because that's a thing you can do (for free!) in London. I find it mind boggling how much history there is here, and the tour was pretty interesting. Getting up there was a bit ridiculous though - 334 steps up, in a little winding staircase.

There were stories, many stories! Things like when they were advertising for the position of clock maker (way way back in the 1850s), they held a competition for a clock. One of the caveats was that the mechanical (because back then everything was mechanical) clock had to be accurate to 1 second of the time in Greenwich. Clockmakers were outraged - can't be done, they said! Apparently if a clock was accurate to within two minutes then it was a fine clock.

In the end, it wasn't even a clock maker who designed the winning clock. It was a barrister! He devised this great big clock with big weights that drop down the shaft in the middle of the tower, and the drop powers the clock, and and the turning of the hands, and the ringing of all the pretty bells. It's mighty impressive, there are two big trains (one is a chiming train, and the other striking train) for ringing the bells, and a much smaller one for keeping the time (or rather - the hands moving). The two big trains for the bells get wound up electronically every few days (fair call, the weights down the shafts are several tons each), but the clock gets wound up manually.

Also, to keep time, the clock workers put pennies on the pendulum to keep time (because as the barometric pressure changed, so did the speed of the pendulum). The slight weight change altered the centre of mass, which in turn altered how fast or slow the pendulum swung. There are a stack of pennies still up there (most that are antiques now, and probably worth a fair amount of money!) as well as a silver five pound coin. Randomly, the minute hand moves at two second intervals, because thats how long it takes the pendulum to swing from side to side.

Right now they keep time with atomic clock (they call 123 from the tower - so novel). They used to do it by telegraph from Greenwich a few times a day, but now they use the atomic clock because it's more accurate. Which is kind of insane, it uses the electronic transition frequency of atoms (!) to keep time. Apparently this is because they can't use the stars anymore - the earth is slowing down.

Which also blows my mind. I mean, it all makes logical sense (The sun is burning it's own mass, which means it's getting smaller and has less gravitational pull) but the impending doom of earth slowing down just seemed so shocking. I'm hoping our species will figure something out before the inevitable happens.

What else did I learn? Before electricity was installed there was an unhappy gas man. Now that it's not powered by gas they use long lasting Phillips light bulbs that cost £100 each. They have birds of prey - to keep starlings and pigeons off the hands (the extra weight on the arms of the clock slow down the clock...) They have windows in the clock faces, that swing open. The big bell, Big Ben 2, has a big crack down the side (which means the bell now rings at e flat). They rotated the bell a quarter turn, so the crack doesn't get bigger. It's missing a little square chunk out the side, which I didn't expect. Easier than removing a 13 tonne bell that's up a tower, I'd say.

We were up in the belfry just before 12 - there's a click 2 minutes before to warn clock-folk to get out of the way before things start happening. And oh, come noon it was loud. Delightfully loud. Loud enough for the reverberations to travel up through your legs loud. They give you little orange ear defenders, to protect your ear drums.

The view was the best. Unbelievably pretty. Right on the river, we lucked out with blue skies all round. Overall, a fairly interesting tour packed full with information. It was neat to see the inner workings of such a landmark, and to hear the history of all the things.

Fun times all round.