Fascinating video. At first glance it seems a bit Heath Robinson adding a penny to the pendulum to keep it in time but if it's worked for 160 years why change it?

I'm surprised some wag hasn't tried to nick the pennies,meanwhile her is another example of a fine mechanism.

And here is another - it seems that you either like / admire this or you don't

I find it absolutely fascinating in it's design and construction - using a mechanism from nearly 300 years ago with a modern and unique display of the passing of time.

There are other vids on that page which give some different perspectives

This is a BBC vid on the history of the John Harrison clock

The Clock That Changed the World (BBC History of the World)