1675, Charles II appointed John Flamsteed as the first King’s Astronomical Observator, a.k.a., the Astronomer Royal. For that he got £100 a year, use of the brand new, empty Greenwich Observatory, and no equipment. What a deal! He organized some equipment, supplied whathe couldn’t get donated himself, took on students to stretch his income, and set about studying the sky, which was the key to accurate navigation. This mattered intensely because Britain was increasingly a naval power. That makes this a story about power and money and empire, although they’re not what I’m going to tell you about. Brush the words aside, though, and you’ll find them right under the surface.
Flamsteed had come to Charles’ attention by working out a formula for converting solar time to mean time, and for that to make the least bit of sense, we need to take a step or six back, to the time before time was standardized. But before we do, let me sneak in the information that Flamsteed did something at Greenwich that will become central to our story: he drew an imaginary line right through the place and claimed it as the world’s prime meridian–the line that would divide east from west the way the equator divides north from south.
At the time, the only people who cared were astronomers. Everyone else measured east and west from wherever they were standing and life rolled on as if nothing had changed.
Vaguely relevant photo: Navigation at sea comes into the story. Do I need to tell you this is the sea?
Clock time and solar time
For those of us who grew up with clocks–and I’m guessing that’s all of us–it goes against the grain to think that the hour hasn’t always been a fixed measurement, but it hasn’t, and this makes a certain kind of sense. As soon as you wander away from the equator, the day’s length varies over the course of the year, and–oh, hell, you know this–in the interest of domestic harmony, so does the night’s. So when people decided it would be convenient to divide the day into twelve equal segments and the night into twelve more, they came up with segments that were the same in the morning, at night, and at noon but that shifted over the course of the year, following the stretch and unstretch of the day.
Why twelve segments? Don’t ask. It’s what they did. Or at least what they did in the ancient Middle East. What they did elsewhere is on a different page of the book and I don’t have time to read it just now.
That system held until the astronomer, geographer, and mathematician Hipparchus (120 to 190 BCE; you’re welcome) realized that if he couldn’t find a more reliable way to divide time his brain would melt, so he took hold of the equinoxes, when day and night are equal, and measured the length of the segments, and said, “That’s it. This is the length of an hour.”
Only since he was Greek and ancient, he said it in classical Greek. And no, I’m not going to translate.
It was a brilliant idea and everybody who wasn’t a mathematician, astronomer, or some sort of specialist ignored it. Daylight went right on lasting for longer and shorter periods of time over the course of the year and in practice so did the length of an hour. And people kept on using those expandable, contractable hours until–oh, let’s say the 14th century, when mechanical clocks ruined the fun.
And that, children, is the difference between clock time and solar time.
Hipparchus did one other thing that we need to know about: he introduced longitude and its non-identical twin, latitude. Between them, they kept geography from being as slippery as hours.
Longitude
Even after an hour in May had been strong-armed into being the same length as an hour in January, time was still slippery. Everyone could agree that noon came in the middle of the day, but the middle of the day came at different moments in different places, and people set their clocks to local time.
Well, what else would they set it to? Since transportation was slow and phones didn’t exist, hardly anybody cared and I’m willing to bet not many people even noticed.
The people did care, though, were sailors, because you need two fixed points to calculate your longitude. Or to put that in plain English, to figure out where the hell you are, and I’d love to explain why and how but it’s way above my pay grade.
Knowing where you are is less of a problem on land, since you have, ahem, landmarks, and fixed points stay politely fixed, but at sea they’re badly behaved, and the difficulties this posed crashed into public and political awareness in 1707, when four British ships wrecked off the Isles of Scilly and 1,400 lives were lost, all because, through no fault of their own, they hadn’t been able to calculate their position reliably.
Now let’s circle back to Flamsteed and his imaginary line through Greenwich. It was a fixed point that ships could compare their location to. If I understand this correctly–and that’s not guaranteed–they could use solar time at their location and compare it to clock time at Greenwich. All they needed was a clock they could set to the time at Greenwich.
Nothing to it, except that the clocks of the era couldn’t keep time on a ship that was going up, down, and sideways.
At more or less this point, Parliament offered a £20,000 prize–that would be something like £2 million today; in other words, more than enough money to hold people’s attention–for the person who could invent a seaworthy clock, and in 1773 John Harrison, a joiner and watchmaker, did just that. All sailors had to do after that was set it to the time at Greenwich and as long as they remembered to keep it wound they had their second fixed point.
Greenwich Mean Time
For some hundred years, ships used that imaginary line as their ultimate reference point. Think of it as Patient Zero of the world’s time zones.
As the railroads grew, treating time as a liquid began to became less and less workable on land, and Britain’s railroads introduced Railway Time, which was basically Greenwich Mean Time under another name. Localities were welcome to adapt it or not, but since the trains ran on Railway Time, I expect there’d have been a good bit of pressure to reset village and town clocks so people could catch them.
In 1880, Britain adopted Greenwich Mean Time as the national time.
In1884, the international Global Meridian Conference accepted the imaginary line through Greenwich as the world’s prime meridian. By then, the US had already based its time zones on it and 72% of the world’s commerce used sea charts that relied on it. But the conference’s acceptance didn’t commit individual governments to doing anything they weren’t already doing, and most of them didn’t.
Then the Titanic met the iceberg–this was in 1912–and it turned out that a French ship had radioed a warning of the danger, but it based its time on the Greenwich meridian and its longitude on the Paris one. The article I found that says said it wasn’t “the overall cause of the disaster,” but it made a hell of a good argument for getting everyone to use the same system and it actually swung a few more countries behind it.
The original imaginary line is now marked in brass, making it a real line, even if it’s not exactly the line that’s in use anymore, In the name of accuracy, efficiency, and confusion, it’s been nudged sideways a few times. Never mind, it made its point.
These days, international standardized time is called Coordinated Universal Time. And Greenwich Mean Time? It’s been downgraded to a simple time zone.
Notes from the U.K. 
Excellent and amusing, as usual, Ellen. Just a couple of remarks. The use of Coordinated Universal Time doesn’t stop the French from having a try at claiming that the Prime Meridian should go through Paris, on the grounds (I think) that we use BST for more than half the year and it’s often floated that we should stick to it all year. I find myself, irrationally, mildly annoyed by this, given my normal mode of “patriotism is the last refuge of the scoundrel”. I forget who said it but I’m sure it can be found somewhere out there, if anyone cares.
Secondly, the history of the development of accurate clocks to establish longitude is absolutely fascinating. The horrific wreck is a classic illustration of the disaster of discipline being enforced, at any cost, by the terminally stupid . I recommend the book “Longitude” by Dava Sobel if you want the full story (there was also a programme by the BBC about it). It seems that a member of the crew was keeping a check on the position of the ship and told the officers that they had there sums wrong, thus avoiding being drowned: he was hanged for insubordination. So it could be argued that some, at least, of the victims got what they deserved.
The tale of Harrison’s reward is also steeped in class snobbery. The clocks themselves were a few years ago on display in the Greenwich museum and probably still are. They are exquisite examples of the beauty that can result from dedicated craftsmanship. At least two were actually made of wood (Harrison was a carpenter) but he moved into metal. Wood was probably not the best thing to rely on in the damp environment of a ship at sea, anyway. If you’re ever out that way, I recommend them as showing a perfect marriage of art and practicality. The politics of the awarding of the prize adds to the tale of the intransigence of the hierarchy of the powerful. History turns me into a class warrior at times. Anyway, thanks!
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Many thanks for the additions. I remember reading reviews of the book and it did sound fascinating. That was, unfortunately, as close as I got. However, I did ask Lord Google about the quote, which I remembered as “… the last refuge of fools and scoundrels.” I got as far as “last refuge” and Lord G filled in “of the scoundrel.” I went with that and AI–pushy little snot that it is–jumped in, repeated the quote, and told me it was attributed to Samuel Johnson. I went back and filled in my version, “fools and . . .” and AI repeated that version and told me, with a straight face, that it was also attributed to Samuel Johnson. If I asked about “fools, scoundrels, and hairdressers” it would probably also attribute it to Samuel Johnson but by then the fun had gone out of the exercise.
(“Scoundrels” does seem to be correct, but I like my version.)
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Not one but four British ships were wrecked near the Scilly Isles resulting in the deaths of over 1,400 sailors, including the Admiral, Sir Cloudsley Shovell (what a fantastic name).
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Somehow this came through twice, so does that make it eight ships?
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Not one, but four British ships were wrecked off the Scilly Isles in 1707, resulting in the loss of 1,400 lives, including that of the fleet’s admiral, Sir Cloudsley Shovell. I remember learning about this at school. Who could forget a name like that?
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“Sir” is absurd enough, but Cloudsley Shovell? This proves my theory that the more absurd something is, the longer you’ll remember it.
Thanks for the correction. I thought that was a lot of people to cram onto one ship at the time. I should’ve checked and I’ll update the post so I don’t look like quite so much of an idiot.
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beautifull
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Thank you!
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I guess all this is about celestial mechanics, triangulation, and cardanic suspenders, so excuse me please, much too much “natural” “science” for a simple Franconian. I know that somewhere here in the region the geographical centre of the EU is to be found, what is all I know about latitudes & longitudes.
BTW is the zero meridian still cut through Greenwich, or did the world move on ? It all went downwards with the damn French metric system, eh ? Interestingly in a Sixties German SciFi series the bad invaders were called “The Frogs” – those were the days !
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The meridian still runs through Greenwich. The shift was a small one.
I have immense gratitude to the French for creating the metric system, since I can reliably multiply anything by ten. After that, it’s up for grabs. But I still think in feet and inches. After living with them for so many years, I more or less instinctively know how big they are.
Do cardanic suspenders hold up your trousers (or if we’re speaking American, pants) or your socks?
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Sir Solly Flood was the judge at the RMS Titanic investigation, speaking of naval names.
There was a lot of bits and pieces I had had a nodding acquaintance with, but this article brought it all together in a coherent way . Thanks for a very informative piece. (The US had a similar problem out west – trying to keep track of Chicago Time/Railroad time. For instance, there is a discrpancy as to what time the Battle of Little Bighorn was – ten am, noon, four pm…
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That’s one hell of a range, from 10 a.m. to 4 p.m. How’d they manage to stretch the discrepancy that far?
Sir Flood? Put that in a novel and someone would say, “Oh, come on, will you change that to something marginally believable?”
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As a point on the daftness of the use of titles, he would be Sir Solly, not Sir Flood. The subtleties(?) are pretty much incomprehensible to anyone not steeped in the vagaries of the system. I have a handle on some of it but not by any means all. Life is too short, unless you work for Debretts.
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Now that you mention it, yes, I knew that. For better or worse, I don’t store that bit of knowledge in the part of my brain where I keep working knowledge. And Debretts, to my credit, would never hire the likes of me. I’m sure they feel good about that as well.
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Very interesting article Ellen—on many fronts. The stubborn resistance to adopting the new system is amusing but I guess not surprising.
What is BST, the British equivalent of DST in the U S?
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BST is British Summer Time–basically daylight savings time. I find it mildly confusing to have but ordinary summertime, as in school’s out and it’s warm, and Summer Time, as in set the clocks an hour ahead, but there are worse things in the world. Entirely too many lately.
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Time is certainly an interesting construct!
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And like so many things looks simple until you think about it.
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So the prime meridian was never actually the International Date Line?
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No, but it’s relevant to the international date line, which was set halfway around the world from the prime meridian, back in the 19th century. So a city in New Zealand is always the first place to greet the new year.
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Very cool.
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It had never occurred to me that hours would change shape before clocks came along and made them stand in line. This makes so much sense! Interesting factoid that may or may not be true – although it also made sense to me: apparently many humans don’t really follow a 24 hour clock … It’s as though we evolved somewhere that days are just an hour or so shorter. I have a hell of a time functioning on a rigid 24-hour cycle. Left to follow my nature, I wake a little earlier every morning, and run out of steam a little earlier every night, and at 3.00AM today I finally decided that after 67 years of trying to squash/stretch my brain to fit an alien sun cycle, and will henceforth simply dance to my own rhythm.
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Some hundred or so years ago, I remember seeing an article about someone who spent–oh, I don’t know: a month? a year? maybe it was a month that felt like a year? Anyway, spent some time in a cave and fell into, I believe, a 25-hour sleep-wake cycle, giving further backing to your theory that we’re not really from this planet. With a sample of two people, how could this possibly not be true?
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Exactly! And it explains so much. It’s so obvious that this planet is an outpost in a massive war between Goodies (us) and Baddies (orange), and if we simply follow our natural biorhythms we might, finally, win.
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Um, yeah, I knew that.
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