Dan and I both enjoyed reading Longitude by Dava Sobel, which describes the challenge of determining the location of a ship at sea, and the solution to the problem through the development of a reliable clock. (This is not the place to elucidate the problem or the solution; just accept the obvious fact that ships need to know where they are, and that navigation hasn't always been as easy as GPS.)
Coming to London meant that we absolutely wanted to go to the Royal Observatory at Greenwich, where both astronomy and chronometry have a long history, so we did that on Wednesday. While in Greenwich we went to the National Maritime Museum, where -- duh-- we saw lots of ships, and we also saw the Cutty Sark, the last of the multi-mast bazillion-sail Clipper ships bringing tea from Asia at then-blinding speeds. Today we went to the British Museum, where we saw (in addition to the Rosetta Stone and stunning Anglo-Saxon remains found in 1939) more stuff about ships and clocks.
So first to Greenwich. Here's a view through the rain of the Observatory on the hill:
and here are some of the time-keepers of interest:
a twenty-four hour clock
a wall-mounted year-round sundial
and "H1," the first clock made by John Harrison that kept reliable time at sea.
We expected the National Maritime Museum to be dark and dusty, with little unreadable plaques. Wrong! It's a very modern museum with many kid-friendly touches and interactive displays, and lots of interesting history. Perhaps a bit kitschy, but very fun, is this display of figureheads from sailing ships:
and nearby, the Miss Britain III, which in 1933 was the first boat to reach 100 MPH on seawater:
John Harrison spent many years on his seagoing chronometers, and here is "H4," which was finally acknowledged to be reliable enough to allow a navigator to determine the longitude of his ship:
And now to the British Museum (a source of endless wonder), and two more time-related objects. This bell-ringer was part of a larger clock, and I just liked the figures:
And finally, this, ummmm, alarm clock not only ran along on its little wheels, but also fired a little gun from its little bow, which set off all the other little cannons. I wonder how many times it actually worked. But it's beautiful:
Last time I was in London, I lost almost an entire morning in one room of the British Museum, learning how a mechanical clock works by watching the Cassiobury Park turret clock in the glass case. (It's in room 38-39; I just looked it up.) It is such a wonderful explanation of the 5 required elements: energy, wheels, escapement, controller and time indicator. Here's a link to a wonderful video of it, which is also viewable when you have the real clock in front of you: http://www.britishmuseum.org/explore/galleries/europe/room_38-39_clocks_and_watches/clock_animation/introduction.aspx
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