Stephen Hawking and the giant time-eating grasshopper

Davey Winder
Sunday, 21 September 2008 21:30

Science - Space

One is an inventor who made his fortune from developing the kettle thermostat, one is a world famous physicist who made his name explaining time, and one has been dead for 232 years. Together, this unlikely trio have brought us perhaps the oddest clock on the planet.

A little background is needed here, perhaps. John Harrison, the father of the ball bearing and the true pioneer of longitude, invented the marine chronometer. He also invented something called the grasshopper escapement, releasing the gears upon each pendulum swing for great accuracy.

He also took 36 years to build one clock, which was still being calibrated by Harrison when he died on March 24th 1776 at the very ripe old age of 83. He was, by all accounts, a remarkable man.

A joiner by trade, the working-class lad went on to solve the problem of longitude by proving, after some 40 years of investigation, that a mechanical clock could be used at sea to locate position with amazing accuracy.

Fast forward 232 years and Dr John Taylor, whose main claim to fame is probably as the inventor of the kettle thermostat, decided to create a tribute to the great man of time.

And so it was that Taylor spent UKP £1 million on the Corpus Clock, unveiled at Corpus Christi College in Cambridge by Professor Stephen Hawking. Described by some as the oddest clock on the planet, the Corpus Clock has no hands.

It does, however, have a giant grasshopper sitting atop the strange 1.5m wide device. The enormous time-eating grasshopper is perhaps the most visible tribute to Harrison, representing the grasshopper escapement.

"No one knows how a grasshopper escapement works so I decided to turn the clock inside out" said Dr Taylor "instead of making the escape wheel 35mm across and hidden in the case, it is 1.5m across and visible with the grasshopper escapement around the outside."

It is, unsurprisingly, the biggest grasshopper escapement of any clock on the planet. Perhaps people will better understand the importance of Harrison and his escapement as a result? I doubt it.

Unfortunately, the clock is only accurate every five minutes. But it has been built to be like this, The rest of the time the mechanical device plays tricks on the watcher by pausing the pendulum and then correcting itself.

It also has an odd habit of whizzing flashing blue lights around the disc, and then freezing them. Time is actually read by watching where the blue lights settle across one of the 60 slits cut into the face of the clock.

If that sounds confusing, it is because it is. And then some. Dr Taylor calls is a chronopage, literally a time eater. Perhaps that is why, on the hour, it gives us the sound of a chain dropping into a wooden coffin, to remind us of our mortality?

There is no doubt that it is an impressive beast, especially as it comes replete in a 24-carat gold coating. And, of course, that giant grasshopper ever rocking upon the top of it.

Who better, then, than the author of A Brief History of Time to officially unveil the clock to the world? Ironically, the time master himself was precisely 14 minutes and 55 seconds behind the planned schedule in unveiling the time-eating clock...