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Science

Centuries-Old Longitude Clock Runs Again 144

Posted by Hemos from the and-the-old-shall-become-new-again dept.
douglips writes "BBC News has published a story about John Harrison's H4 chronometer and how it has been wound up for the UK's National Science Week. After 40 years of work [Harrison] proved in 1764 that a clock could be used to locate a ship's position at sea with extraordinary accuracy." Ah, the GPS system of its day. T. adds: This is the timekeeping device which Dava Sobel wrote about in Longitude .
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Centuries-Old Longitude Clock Runs Again More

Centuries-Old Longitude Clock Runs Again

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  • H.4 Timepiece Background (Score:5, Informative)

    by BrianGa ( 536442 ) on Thursday March 14, 2002 @11:25PM (#3166617)
    This site [anu.edu.au] tells much about Harrison's H.4 Timepiece (picture [anu.edu.au]). Don't forget to visit the official site [harrisonclocks.co.uk].
    • First of all, your references pertain only to the 1st version, NOT to the 2nd (or 3rd or 4th). To really determine the significance of this, one needs to look at better sources. See:

      Former demonstrations at Antioch [scientificamerican.com]

      Pluaralism and the Last Century; implications on H.4 [discovery.com]

    • Atomic clock in 1948 Invented by William Libby ! (Score:1, Interesting)

      by Anonymous Coward
      William F. Libby (american) invented the atomic clock in 1948 and got nobel prize eventually in 1960.

      Britain should review why USA took tech lead 1800s and 1900s instead of endlessly glorifying this achievement.

      Of the top 100 most vital inventions from 1850 to 1950 only one was a British and 99 were american inventions.

      The one Brirish contribution was the Jet Engine, but they had to "give it away for free" to usa military as part of war debt so essentially it is american in a roundabout way.

      Britain spends all its BBC documentary dollars reliving its conquest and Imperial domination empire years again and again.

      Oh how british: a perfect clock to win a prize that Britain was unwilling to honor as the prize winner...

      They should instead study how Americans patented and created the top 99 technological marvels of the years between 1850 and 1950 and quit being maudlin and nostalgic about the British Empire years.

      They are a dying irrelevant kingdom of socialist welfare programs.

      Oh thats right everything hostile on slashdot is automatically a troll eh? Well then do not COMMENT, do not REPLY but not because this is a troll (its not) but because by requesting you not to reply i prove logically and 'de facto' that this is NOT a TROLL. The definition of a troll is that a troller wants a reply or two. I want no replies I said my piece. Go write your own opinions elsewhere and wuit using your British Mod points to stiffle and censor american Free Speech.
      • "I want no replies I said my piece"

        Would have been a little more admirable if you had sufficient courage of your convictions to post under your own name....

      • Re:Atomic clock in 1948 Invented by William Libby (Score:1, Interesting)

        by Anonymous Coward
        Lol... funny you should say that :-

        According to the US Navy [navy.mil] :-

        "In 1958 the Naval Observatory and Britain's National Physical Laboratory published the results of joint experiments that defined the relation between Atomic time and Ephemeris time. (An interesting scientific and philosophical question is whether the relationship between Atomic time and gravitational time remains constant.) Since 1967 the international definition of the second has been based on these joint experiments. Atomic time is kept synchronized with universal time by the addition or subtraction of a leap second whenever necessary."

        According to the NPL [npl.co.uk] :-

        "It was Louis Essen's research into the physics of frequency generation and measurement that changed the way the world measures time. In the 1930s he worked on the first quartz oscillator-based clocks and by the 1950's he had devised a caesium atomic-beam tube which could be used as a clock. This led to a better definition of the second using the world's first atomic clock, built at NPL in 1955."

        And the Canadians [nmstc.ca]

        "A method to replace astronomical observations was urgently sought. The atomic clock, first developed in Britain, was the solution. Scientists at the NRC made a Cesium atomic clock (Cs I) (660528), which went into operation in 1958."

      • Re:Atomic clock in 1948 Invented by William Libby (Score:1, Interesting)

        by Anonymous Coward
        Erm... you don't know your history, anybody worth their scientific salt is aware of Louis Essen [btinternet.com] :-

        "Essen is the only British physicist ever to have been honoured for his contribution to science by both the USA and USSR during the Cold War.

        He received the Rabi Award from America and the Popov Medal from the former Soviet Union."

        Now... William F. Libby was a brilliant Chemist in his own right, but he didn't invented the Atomic Clock, he created C14 dating (carton dating), he recieved the Nobel Prize for Chemistry in 1960, according to the Nobel Institute [nobel.se].

        So ironically you've gone on to prove the very opposite of your insults and suppositions, the Atomic Clock was actually invented in Britain and you quote a Chemist that actually invented something quite different (though still valid).

        Get your facts right unless you want to make an idiot of yourself.

    • H5? (Score:2)

      by gargle ( 97883 )
      I haven't been able to find a picture of H5 anywhere. Is it still in one piece?

      • Re:H5? (Score:1, Interesting)

        by Anonymous Coward
        There is a beautiful picture of H5 in "The Story of Longitude". If I owned a scanner, I'd post it. It is much like H4, but far less ornate.
    • (refer to photo)

      how accurate could it BE, when he can't
      even spell the Roman numeral IV right???
  • I seem to recall some TV show...within the last 2 years, at least, about this clock and the efforts that led to it. Was it based on the book? I think it was on PBS.

    Anyone remember this?
    • Your probably thinking of NOVA.

      www.pbs.org [pbs.org]

    • Re:Longitude (Score:3, Informative)

      by rhysweatherley ( 193588 )
      It was on the ABC in Australia last year, starring Michael Gambon and Jeremy Irons. A BBC series originally I believe.

      It was one of the best science-related history shows I've ever seen, tracing the story of H1 through H4 in a way anyone could appreciate.

      The show also told the story of the WWI soldier, emotionally damaged by his war experiences, who painstakingly restored the clocks in the early part of the 20th century.

      It's amazing how much we owe to Harrison. It's a pity that he had to fight so hard for his compensation, because the upper-class science types of the time refused to believe that a cabinet maker could come up with the solution.

      • Re:Longitude (Score:4, Informative)

        by Graymalkin ( 13732 ) on Friday March 15, 2002 @01:46AM (#3166957)
        It wasn't about a cabinet maker coming up with the solution it was the Board of Longitude being top heavy with astronomers who were looking to solve the same problem by another means. The astronomical society was pitching hard for their method because it gave them some clout when asking for grant money to stare at things in a telescope. At the time academia familiar with the longitude problem were classified as Mechanics or Lunars depending on the particular method they supported to solve the problem.
      • It was a Channel 4 series, I think. Not that it matters that much.

        I feel that Harrison's arrogance may have been a factor. That and society tends to lose patience with new inventions after a very short time. It seemed everyone was rather enthusiastic about the H-1.
        Accurate information is hard to come by since we only have Dava Sobel's book to work from.
        • and, of course, the sources that Sobel drew upon.

          eg:
          "The Marine Chronometer, It's history & Development"
          http://www.rog.nmm.ac.uk/museum/harr ison/gould.htm l
      • hey !! my father in law was in this film. he was one of the burly popeye-type hauling the HUGE clock into position on one of the ships. does not make _me_ famous, of course, but does not make me less so :)
      • Well, it's nothing new. Just think about the treatment of the poor sad soul who suggested that the reason for the large number of deaths during childbirth was the septic condition of the doctors' hands, and suggested a good sterilizing washing. I regret not having his name at the tip of my mind, but he was truely an agnostic's saint. He died in a madhouse as I recall.
    • This was an A&E 2 part miniseries. I watched part 1 it about 2-3 weeks ago, but missed the second part. It was pretty interesting and I'd like to see the rest.

      http://www.aande.com/tv/shows/longitude/
    • The DVD *was* available, and may be again as the video is being (re-?)released and available from Amazon [amazon.co.uk] (DVD [amazon.co.uk]/VHS [amazon.co.uk]) and also Blackstar [blackstar.co.uk].
    • The NOVA film you're thinking about is -- "Lost at Sea - The Search For Longitude."

      Harrison had sailed from Portsmouth, England to Bridgetown, Barbados(West Indies).

      I have a link to the NOVA episode on my personal website.
      http://www.geocities.com/baddboychris/ca rib/bb_bas ics.htm

      Unfortunantly it appears as though it may word-wrap the URL so makesure you remove any spaces in the URL.
    • The NOVA film you're thinking about is -- "Lost at Sea - The Search For Longitude." It talks about how Harrison had sailed from Portsmouth, England to Bridgetown, Barbados(West Indies). I have the link to that NOVA episode on my personal website. http://www.geocities.com/baddboychris/carib/bb_bas ics.htm Unfortunantly it appears as though Slashdot may word-wrap the URL so make sure you remove any spaces in the URL.
  • Sorry, couldn't resist that one.

    Feel free to mod as you see fit.

    • I guess that none of you noticed that I AM JOHN HARRISON, making a joke in the parent post about the story being about JOHN HARRISON. Or maybe you did see it and didn't think it was funny. Either way you are idiots. I bet you are so proud of yourselves, keeping /. joke free.

      • Re:Idiot Moderators! (Score:1, Funny)

        by Anonymous Coward
        I've always been partial to George Harrison. Odd that it was Ringo who played drums and kept the beat on time.

  • Nice. (Score:2, Interesting)

    by Renraku ( 518261 )
    Pretty interesting concept for its time. Pretty easy to think of if you could see the big picture. But back then, they couldn't. Gotta hand it to Harrison. Good idea.

  • Pratchett and Time (Score:3, Informative)

    by Bonker ( 243350 ) on Thursday March 14, 2002 @11:35PM (#3166647)
    I saw the special about Harrison and his clock just a few days after I read 'The Theif of Time', arguably one of Pratchett's better books of the aging Discworld series. Not surprisingly, the non-plot themes are somewhat similar... the quest for the perfect material with which to build clock springs.

    Reading about this makes me want to read it again.

  • The remarkable, unique Harrison clocks (Score:5, Interesting)

    by Bolen ( 4896 ) on Thursday March 14, 2002 @11:41PM (#3166661)
    The interesting thing about the Harrison clocks, is not only were they the GPS of their day, they were also the atomic clocks of their day.

    The Harrison clocks, created in the 1700's, are still more accurate than your average digital watch today.
    • The Harrison clocks, created in the 1700's, are still more accurate than your average digital watch today.

      However your adverage digital watch today, would be a lot cheaper...

      For that time it would be understandable that a clock would be a useful tool to help you understand where you are. It would have also been invaluable in giving an indication of the time of day.

      I say "help" because it alone would not be able to provide the necessary capabilities without the person/people using it referring to other mechanisms and/or observations. It is only when you put all of this together that you have the means to calculate where you are.

      This is the same with the GPS receiver. It is useless without the GPS satellite network, even though the device itself contains a fair degree of "number crunching" capabilities.

      It would also be cheaper for the GPS receiver unit now than it would have been for the Harrison clocks, when they were constructed.

      .. they were also the atomic clocks of their day.

      That they certainly were. And with this we can compare to the atomic clocks of today, as far as cost is concerned.

      • No argument about the cost, although the prize money was well worth the effort for John Harrison personally. I still find it amazing that a mechanical clockwork can be so accurate.

        Harrison's work was a triumph of craftsmanship, but no Captain could be expected to afford one, unless he came from a very wealthy family indeed. The British government wasn't going to pay for the cost of, an "atomic clock" if you will, in every ship either. In the end, it was producers of cheaper (and inferior) imitations that wound up in the pockets of Captains.
    • The interesting thing about the Harrison clocks, is not only were they the GPS of their day, they were also the atomic clocks of their day.
      Not only is GPS the GPS of today, GPS is also the atomic clock of today [howstuffworks.com]. And a great source of accurate time if you want to run NTP on an isolated network.

  • clock vs watch (Score:5, Insightful)

    by Alien54 ( 180860 ) on Thursday March 14, 2002 @11:42PM (#3166665) Journal
    Every one says clock, but what it is really, is a watch.

    That is what screwed everyone up at the time, because the majority of folks were into heavy metal and wood and so on. Pendulums are messy on ships.

    The spinning mechanisms of mechanical watches are much more stable, and this, with the miniaturization, proved to be the key.

    The professionals could not deal with a simple "watch" that was the first chronometer.

    • "...the majority of folks were into heavy metal..."

      But heavy metal wasn't invented until the early '70, pioneered by groups such as Black Sabbath [cdnow.com], gaining more acceptance in the mid-to-late-70s with bands like Judas Priest [cdnow.com], AC/DC [cdnow.com] and KISS [cdnow.com], eventually being brought to the mainstream by Metallica [cdnow.com] and Megadeth [cdnow.com], and finally sold out, combined with the failed Punk movement, and/or integrating elements of Rap and Alternative music into the bands we know & hate today: Linkin Park [cdnow.com], Limp Bizkit [cdnow.com], Korn [cdnow.com] and Godsmack [cdnow.com].
    • In spite of its appearance, the H4 is a bit too big to really be carried around as a watch.

      Chronometer is a better term, since the Harrison clocks (the term used at the time) were specifically built for use at sea, include bi-metal parts to counter the effects of temperature changes, and were designed to run steadily even as the tension in the mainspring changed during the day, or while being wound.
      • In spite of its appearance, the H4 is a bit too big to really be carried around as a watch.

        True enough, but then at the time the only comparison _were_ watches, even though it is a bit larger. The technology was of the same class, which is why the judges had so much problem with it. They had no way comprehending the technology of a "watch" on steroids

        • Hmmm. Sounds rather like the way pointy-haired bosses today are more impressed with the Lebert A/C units out on the computer room floor than the Sun and HP servers nearby.
  • Longitude the movie was pretty cool, and has been airing on A&E a lot recently late at night...

    And you get to see a prop version of the H1 running -- some cool mechanical engineering; even though the first 3 didn't really work on the open sea.

    Longitude [imdb.com]

    • Movies vs. History (Score:2, Informative)

      by Bolen ( 4896 )
      I confess I haven't seen the movie. I hope the movie didn't say the first 3 clocks didn't work at sea.

      The H1 worked quite well during its sea trial. Harrison could have won the Longitude prize based on the trial of the H1 if he hadn't been such a perfectionist, and declared he could do even better, thus putting off an immediate financial gain. By the time the H2 was ready, there was a change in leadership at the Royal Observatory, now hostile to Harrison's efforts.

      (I'm writing this from memory, so I don't remember the details. I believe at least 3 of the clocks were tested at sea, some under conditions intended to make them look bad, such as not being wound consistently.)

      • According to the movie, the first H1 was effective at sea, but not up to the inventor's desires.

        I'm not sure if this was added for drama or not, but the plot went like this: SPOILER? his calculations differed from the captain's calculations at a critical point in the voyage.

        Disagreeing with the captain at sea was not a good idea at the time -- it would have been considered mutiny.

        They were following the captain's calculations, but they had the inventor's concerns in mind. Because of these concerns, they were able to determine they were in fact off course before it was "too late" and were able to change to a safe course.

        The captain chose not to put this incident into the ship's log, so the inventor had no evidence of this until a first mate came forward.

        The inventor then got the funding to continue development with the H2, where more significant accuracy issues were discovered...

        • Sounds like a bit of dramatic license.

          In fact, it was quite safe for John Harrison to disagree with the captain, since he was there to mind the clock, and the primary purpose of the voyage was to field test the H1.

          The captain maintained his own set of records using the traditional "dead reckoning", while Harrison maintained his independent records using his clock. The purpose was to have a basis of comparison, to see which method was more accurate. When Harrison's calculations proved to be superior, the captain became his most enthusiastic supporter.

          If a CREWMAN disagreed with an officer's findings, OTOH, he was subject to being hanged on the spot for mutiny. This in fact happened to a crewman a few years earlier. As it turned out, the hanged crewman was right, the officers were wrong, and the fleet ran aground, killing many men. The captain who order the hanging made it to shore, but was killed and plundered by a thief as he lay on the beach. This event was one of the reasons for offering a prize for a method to determine longitude.

  • Connections (Score:3, Interesting)

    by fishbowl ( 7759 ) on Thursday March 14, 2002 @11:58PM (#3166703)
    James Burke mentions this in the Connections tv series. A lot of people tried and failed to make a clock accurate at sea.

    I wish I could get that series on DVD.

    • A lot of people tried and failed to make a clock accurate at sea.

      I wish I could get that series on DVD.

      I wish I could make a DVD accurate at sea. I mean, get it to respect the DVD zoning regulations, like switching to the American zone when I get to America. That would really be compliant with the Law.

      Hmm, guess that means the thing would have to be able to play multiple region DVDs... Mine doesn't. So mine is not compliant? oopsie, got to go buy that Region-X stuff before the cops come and get me!

  • Greenwich (Score:5, Interesting)

    by BinxBolling ( 121740 ) on Thursday March 14, 2002 @11:59PM (#3166704)

    I was in London last November, and visited the Royal Observatory in Greenwich. I was familiar with the Harrison clocks and story, but I hadn't known they were kept there. So it was a pleasant surprise to find them there. If you're a geek and you happen to be in London, it's well worth your time to go take a look.

    The first three clocks are these large (roughtly 1.5 ft in each dimension) contraptions with lots of visible moving parts, wooden gears, etc. Then you get to H4, and it's this elegant little package. The leap between the first three clocks and the fourth is enormous.

    There's a fair amount of other neat stuff at Greenwich, too. They have a number of displays about the development of "time infrastructure". I remember reading one bit that talked about how, in 1852 (I believe), Greenwich began transmitting the time to the rest of England via telegraph. I couldn't help but be reminded of how clock signals are distributed around a CPU and other synchronous logic devices, and think that maybe humanity is somewhat more borg-like than we usually acknowledge.

    • There's a fair amount of other neat stuff at Greenwich, too.

      I got taken there several times as a kid. The 'neatest' thing to me was always standing on the meridian line (0 Longitude) and saying 'This foot is East and that foot is West..' at the time it seemed like the most amazing thing to do..
    • Definitely do Grenwhich all of it and I hope you took the boat down the Thames and then on another day go to the Water works Museum in Syaon Park (or is it Kew) and then go too the Irom Bridge Museum and take a ride on the Romney Hythe and Dimchurch small gague railway...British Engineering is quirky and Amazing. But my question is when is someone going to do something proper for Alan Turing. I wrote my first programs on a Pegasus at ICT Ferranti (Turings Co) in 1963. The White Hart Inn is just around the corner (common you Arthur Clark folks) Its about time someone wrote about the dawn of computing time in London Didja know that most of the non Governmental computers in London in 1960 or so were on one Street Newman Street??? and IBM and ICT shared a transformer (Which blew at least once) The only private entity who had his own computer was Fred Hoyle Maybe this needs a new heading like "DAWN OF COMPUTER TIME" in London...How do you do a new Heading????

  • good example of a disruptive technology (Score:5, Informative)

    by jgg ( 566642 ) on Friday March 15, 2002 @12:12AM (#3166738)
    Harrison's sea clocks are a great example of a disruptive technology. His clocks were competing against stellar navigation, and the judging for the award he earned after decades of stonewalling, was done by the royal astronomers. Also - I'm finally posting (my first post!) because for some reason it drove me crazy to read on the main page that it was a clock (singular) that provided a longitudinal position. It takes 2. One set to GMT, the other set to local time, determined by solar noon. The difference provided the longitude. (1 hour = 15 degrees) And it was the ability of H's clocks to keep gmt accurately - (to Jamaica and back!) that made it effective. JGG

  • The Island of the Day Before (Score:3, Insightful)

    by cindy ( 19345 ) on Friday March 15, 2002 @12:16AM (#3166757)
    There's a surrealistic novel by Umberto Eco about attempts to solve the longitude problem through alchemy and strange "scientific" experiments 120 years before Harrison. It deals with the blury line between science and supersition at that time (not that it's all that clear now), and with the importance of knowing longitude for military advantage and empire building. A very strange story told through the eyes of a clueless young nobelman trapped into an insane voyage of discovery.

  • Knowing where you are at (Score:5, Insightful)

    by perdida ( 251676 ) <thethreatproject@yahoo. c o m> on Friday March 15, 2002 @12:43AM (#3166819) Homepage Journal
    do bot discount the utility of knowing where you are at. the modern stock market came up because bizzes were able to trade and do shit like predict the weather and their upcoming returns.

    Investment in the future used to be a non-rational thing. Due to the cultural and religious shit that was impressed upon your kids, you could count on their supporting you in their old age.

    When the advanced navigational techniques of the 16th and 17th centuries were developed, people could predict their futures. They would say, :when my ship comes in."

    When my ship comes in sounds antique and slow, because a ship could take 2-3 years between leaving, laden with cargo, and returning, bursting with trade.

    But, compared to the generation-long gambles on farms and marriages (the prominent speculations of their time), a ship coming in was as rapid a return on investment as a new technology can be today.

    It's great to know where we are - exactly where we are, in physical time in space. I am in awe of it, myself. Place yourself in the proper context of history, and you will know the context of your own experience.

  • Relativity and Navigation with GPS (Score:5, Interesting)

    by schmaltz ( 70977 ) on Friday March 15, 2002 @12:46AM (#3166825)
    Even today H4's legacy remains very much alive. "What H4 was doing is still current today because in GPS, for example, accurate time standards are required for navigation," said Jonathan Betts. "You'd be surprised how clocks rule our modern lives."
    Time's important for GPS, and what's interesting is that relativity predicts time rate differences for pairs of clocks [metaresearch.org] (and thus GPS) due to velocity and gravity differences:

    Clocks in heavier gravitational fields tick at a slower rate.

    Clocks in faster relative motion tick slower.

    So:

    A clock at the equator ticks slower than a clock at the north pole, because the relative velocity of objects at the equator is higher than those at the poles (the axis of spin) due to earth's rotation, but,

    The equator clock will tick faster because it's located farther from the earth's center of mass (due to earth's spin, it bulges a bit in the middle) resulting in slightly lower gravity- and the effects don't always cancel each other out.

    So then,

    Relativity predicts that atomic clocks onboard GPS satellites will tick faster by about 50 microseconds per day (compared to ground-based clocks), due to the weaker gravitational field in orbit, but,

    They also will tick slower by about 7.2 microseconds per day, due to the satellites' orbital velocity.

    GPS's designers compensate for this by changing base time rate for the clocks onboard satellite.

    Fun facts:

    The cesium atomic clocks onboard GPS satellites are accurate to about one nanosecond, and light travels about one foot in one nanosecond. Hence, the best accuracy of GPS is about one foot.

    GPS satellites have been used to experimentally verify that light moves at constant speed at all times/locations visited by earth.

    And there are other confirmed predictions as well. One other I've heard is that GPS's radio signals experience frequency shift due to earth's gravitational field (photons want top accelerate but can't surpass C, so the acceleration energy increases their frequency) and this had to be compensated for as well.

    Time be time.

    • Cesium beam clocks are accurate to 10^-17 seconds. There is a figure that the programmers and hardware junkies of slashdot can appreciate.
    • GPS can be accurate to around 10cm when using differential GPS (http://gipsy.jpl.nasa.gov/igdg/ [nasa.gov].

    • Clocks below you tick more slowly, and clocks above you tick more quickly. This would be true even in a uniform gravitational field. Of course, the gravitational field around the Earth isn't uniform, so clocks below you tick more and more slowly the more down they are. So, there's a linear change and a nonlinear change. Fortunately, the linear part can be compensated with a constant factor, so it doesn't require much math. Also, the nonlinear part isn't so great as long as you are on the surface, and you can't get the signals in deep mine shafts anyway.

    • Each GPS satellite has two cesium and two rubidium atomic clocks on board. Belt, meet Suspenders. Suspenders, meet Belt.

      burris
  • It took over 45 years to develop a watch that kept time accurately at see. And loosing over a second a day of accuracy was considered accurate!

    It is amazing to think about the rate at which technology is improving. The changes we see in our life time are clear evidence of an acceleration in the rate at which technology is advancing. It was only since about the time of Jules Verne that technology has begun to change rapidly enough that humans recognize its effect on society. It was this recognition that was necessary to give birth to speculation about the effect of technology on the future, otherwise know as science fiction.

  • The H clocks are cool and on display (Score:5, Funny)

    by thogard ( 43403 ) on Friday March 15, 2002 @01:21AM (#3166896) Homepage
    They are at the greenwich museum. The early clocks were made mostly of brass so they are big shiny metal things. With enough Lego's you could make your own working copy.

    The Museum is in Greenwich England. Its at 51 degrees, 28 minutes 38 seconds north of the Equator but I don't remember what its longitiude is but its close to London.
    • I think the longatude would be zero
    • The Museum is in Greenwich England...I don't remember what its longitiude is
      I'm assuming that you mean the National Maritime Museum [nmm.ac.uk]. Given it's location (Greenwich), I'd say it's longitude is pretty close to zero [nmm.ac.uk]; it looks like the far eastern point of the building might be exactly zero, in fact. The zero line runs through Greenwich (that's how zero longitude is defined).
    • I don't remember what its longitiude is

      Words fail me.

      The British established how to determine the longitude at sea, and their observatory was at Greenwich, so naturally the longitude is zero. There's a marked "zero" line going through the courtyard. This is actually a little different from the actual zeroes used by various different mapping systems (GPS will probably tell you you're not quite at zero if you stand in the courtyard of the observatory, for this reason). But the zeroes are all based on the Greenwich meridian.

      There used to be quite a few competing meridians. Philadelphia was one, Paris another, and quite a few other places. Greenwich was chosen as the international standard in 1883, but the French held out with Paris until 1911.

      • Surely it is your sense of humour that is failing you.
      • There's a marked "zero" line going through the courtyard. This is actually a little different from the actual zeroes used by various different mapping systems (GPS will probably tell you you're not quite at zero if you stand in the courtyard of the observatory, for this reason). But the zeroes are all based on the Greenwich meridian.

        The brass line across the courtyard marks the old zero meridian. The "real" one changed when the officials at the Royal Observatory moved the transit instrument that made the observations which actually defined the Prime Meridian.

        Derek Howse wrote a very good story of Greenwich Time and Longitude [amazon.com], which has recently been updated.
    • The Museum is in Greenwich England. Its at 51 degrees, 28 minutes 38 seconds north of the Equator but I don't remember what its longitiude is but its close to London.

      He's making a joke. Laugh.

    • its zero degrees exactly. The prime meridian goes straight through the building.
  • They don't build 'em like that anymore.

  • Still the rage (sort of) (Score:4, Interesting)

    by guamman ( 527778 ) on Friday March 15, 2002 @01:32AM (#3166929)
    Mechanical clocks and watches are still hand manufactured by a company in sweeden after 200 years. They are accurate up to 1/10 of a second per week and the spring mechanisms have gotten so advanced that they go for a month without rewinding them. This may not sound so impressive in a large clock, but consider that this is all done in a watch! The only downside is due to the lack of trained watchmakers and the fact that these are all handmade, each watch can run you several thousand dollars! But think of all the money you'd save on batteries.
    • Mechanical watches are made by dozens of companies today, including Swiss Rolex [rolex.com], Omega [omega.ch], IWC [www.iwc.ch] and dozens of others, even Swatch. Even Seiko [timezone.com] makes mechanicals (although mostly for the Asian market). The Chinese make a bunch of cheap movements and the Russian company Poljot [acoola.com] makes an interesting line of affordable watches. Accuracy ranges from +/- 1 second per day on high-end Swiss watches to +/- 20 seconds per day on the Russians. In general anything under +/- 6 seconds per day is considered good. However, there can be a great deal of variation from watch to watch. Rolex, Omega and other mass market companies do little or no hand work in their mass market lines. When you get to a company link JLC [www.jlc.ch], and others, every watch gets some hand fit and finish. However, none of them can be wound only once per month. Most have about a 40 hour power reserve. A few have an 8 day reserve (notably an IWC [www.iwc.ch], and an Eberhard [eberhard-co-watches.ch]. Of course just about every company offers an automatic watch that is wound by the movement of the wrist through out the day. Those watches should "never" need winding if worn every day or two. Everything you ever wanted to know about mechanical watches can be found at Timezone [timezone.com]. Be forewarned, most of these guys think of watches under about $5,000 as "mid priced".
  • ...but the author kind of flagged near the middle and half-heartedly over-dramatized some sections near the middle, to make it more lay-person-friendly, I think.

    Pretty interesting, nonetheless.

  • For me the most interesting part of the story is that after making the fist three clocks, Harrison took a completely different approach to the problem, and ended up with a much more elegant design.

    I've always preferred an analog watch to a digital one. For me you get a much better sense of the passage of time than with a digital. Not to mention they have a charm that you don't often find in a digital.

  • In creating his clocks, John Harrison invented the bi-metallic strip [google.com], fundamental to most thermostats.

  • Not quite accurate (Score:2, Interesting)

    by WINSTANLEY ( 229048 )
    IIRC from reading Longitude, some of Harrison's earlier models (perhaps as early as H1 or H2) actually performed more than adequately during sea trials. As for certifying the results of the sea trials of Harrison's clocks (and giving Harrison a rather hefty prize), the Board of Longitude never actually did this due to alot of political Chicanery (there were astronomers on the board who favored a Rube Goldberg method of measuring the moons of Jupiter (Saturn?))

    A bit of trivia, I was watching My Fair Lady recently and if you remember the foreign accented professional rival of Higgins at the Diplomatic Ball is revealed to be the affected son of a provincial watchmaker who becomes rich. I assumed this was an allusion to the Harrison episode (he eventually did get a huge prize awarded by the King).
  • Jonathan Betts, curator of horology at the observatory, said the simultaneous running of all four chronometers would not be repeated in the foreseeable future.

    "It is a huge privilege; it is one I won't take for granted," he told BBC News Online. "I think it is incredibly exciting. It is a true honour."

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