Going Around In Great Circles

Guest Post by Willis Eschenbach

I’m sure many people know this, but a “great circle” is a circle that goes clear around the entire globe, and whose center is at the center of the globe. A “meridian”, on the other hand, is a great circle that passes through the poles. Lines of longitude are meridians, for example, while the Equator is a great circle. And the “Prime Meridian” is the line of longitude that goes through both poles .. and right through the Greenwich Observatory.

On the other side of the planet from where I am now, the Prime Meridian is called the “International Date Line”. Inter alia, it runs through the island of Taveuni. And I’ve stood there in Taveuni astride the Date Line, with one foot in yesterday and one foot in today.

So it was with great satisfaction that I was able to do the same on this half of the planet. The ladies went to Harrods, and as a good seaman should, I went instead to the Greenwich Observatory, where the measuring of time zones started. Here’s the “evidinks”, as Popeye would say:

The Observatory is a fascinating place for a seaman like myself, filled with the history of how man learned to navigate the globe. It’s on one of the highest spots around London, at no less than 153 feet above sea level. Here’s a panorama of about 120° of the view, Millennium Dome on the right, downtown on the left, from the top of the hill, Greenwich Park in the foreground. Click on it (or any of the other pictures) to get the larger version:

One of the more amazing displays at the Observatory was of the four marine chronometers built by one of my personal heroes, John Harrison. He’s my hero for a couple of reasons. First, because like me he was self-educated, although to a greater degree. Second, because over thirty years of patient experimentation he invented the first successful marine chronometer accurate enough to determine where you are on the planet. Each of his four designs represented years and years of work, each contained a host of new ideas, until finally it all came right. There’re photos of his chronometers here.

Now, I sailed the ocean before GPS, and I’m a reasonable good celestial navigator. The theory of celestial navigation is simple. Let’s use sunrise as an example. If you know the exact time the sun rises where you happen to be, then you know which line of longitude you are on. Easy as that (with the usual caveats, refraction, etc.) … but only if you know exactly, to the second, what time it is. And that was why lots of seamen died before John Harrison invented his chronometer … they didn’t know what time it was, so they didn’t know where they were.

Now, of course, I didn’t have any expensive marine chronometer when I sailed, few people did. But that didn’t matter, because the BBC broadcasts time signals, in the form of six beeps, every hour on the hour. So all I had to do was compare my cheap watch to the radio just before I took my sextant sights. Then when I took the sights, I marked the time from my watch. When I went to work out the sights, I corrected my watch time based on the BBC’s accurate time.

Having spent many and many a morning and evening in the middle of some ocean or other, waiting for the boop-boop-boop-boop-boop-beeeep of the BBC’s time signal, it was a great satisfaction to me to see the actual clock which had been used to produce that very time signal. Indeed. the entire trip through the observatory was in the nature of my homage to the brilliant Englishmen who had done so much to make my life’s oceanic travels possible. For example, back in the days before radio they needed to be able to pass an accurate time signal to anyone in the Thames. To do that, they mounted a big red ball that can slide up and down a pole, viz:

A few minutes before 1:00 they raised the ball up to the top of the mast, and then at exactly 1:00 they dropped the ball … and all of the navigators on vessels up and down the Thames could set their chronometers to the exact second. Simple, and brilliant.

While I was in Greenwich, I also went to the Maritime Museum and the Cutty Sark. When I was a kid living on a cattle ranch, I dreamed of the ocean, and among other things, I put together a model of the Cutty Sark, with all of the spars and rigging and all. So it was almost a shock to see the real ship … it was a bit larger than I remembered it.

In the Maritime Museum, there is the most steampunk real actual vessel I ever saw, from memory called the “Miss England III”. It held the water speed record back a while ago. It’s made of riveted aluminum, and looks deliciously Victorian despite being built (again from memory) in the thirties.

Click on the picture, and enjoy the detail … it just needs a couple of very British maniacs with leather-rimmed goggles and it’s good to go.

So that was yesterday. Today was another lovely warm, even hot day. We went first to the Natural History Museum. It was good, but I wouldn’t rate it as great.

However, we went on from there to the Victoria and Albert Museum, and that museum was absolutely stupendous. Here’s the chandelier in the entry, how could you not like a museum with such an outrageous juxtaposition of the old and new? …

The building itself is astonishing, with immense high ceilings carried on steel arches down into stonework walls with delicate fretwork. And the contents, my goodness, the contents. The basic news is that they have everything from everywhere, and then some, and then a few dozen more. And then a couple more cases full, with (I’m sure) more in the basement. And there were surprises around every corner. For example, I’ve often wondered why it took so long for people to put wheels on suitcases … when I was a kid, hardly any suitcases had wheels. But to my surprise, I found out that it wasn’t a new idea at all …

So as a place to go on my (sadly) last day in London, the V&A Museum was simply superb. On the way out, I asked the guard if Vickie and Al ever came around to visit their most awesome museum, because I was hoping to thank them for their work. He coldly informed me that they were late. “How late?” I asked. He said Al had been late since about 1860, and she’d been late since 1901 … I figured if they were that late it wasn’t likely they’d show up today, so we left and went back to the flat. Can’t have everything in this life, I guess, and at least now the internet is back on in the flat.

Tomorrow we’re off to see Stonehenge et al., on Saturday we’ll be in Bath, and from there … who knows?

My thanks to all for their suggestions and good wishes. As mentioned, my phone is 074 4838 1774. I can’t say I’ll answer all the texts, but they are read and appreciated whether answered or not. We have no reservations north of Bath, so advice on (inexpensive) places to stay is always welcome. The dang money here seems to be made out of ice cream or something, a pound melts away awful fast …

Regards,

w.