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

this story is about a moment when the world changed forever it involves disaster at sea and amazing feats of exploration it all started with one man just over there in North Lincolnshire but eventually it drew in the Royal Navy the greatest minds in the land and a king himself and at the center of it all was the clock in this film I'm going to discover how an amazing clock from Northland culture change the world and how it's still changing the world and like any modern driver I'm using one of these to find it and there's a direct link between sat-nav and the clock I'm about to visit I'm incredibly excited by this this clock was made by one of my all-time heroes John Harrison there are only two others like it in a world and there was well over a million pounds each you have reached your destination just here this is um aa precision pendulum clock number two by John and James Harrison that is wonderful this is our object precision pendulum clock number two made by the Harrison brothers John and James in 1727 the clocks signed by James who may have made the case but the brains was older brother John they made it in Barrow on humba Harrison made just three of these clocks they were incredibly accurate to within a second a month that's the accuracy that they achieved with the precision pendulum clocks one second a month one second a month was an unprecedented accuracy they would have been the most accurate clocks in the world he must have lain awake at night must be dreaming about how to improve things yeah I think he probably had a very one-track mind the most shocking thing about this book is that the working bit the movement is made mainly from wood not what you'd expect from the most accurate clock in the world this is a big day for precision pendulum number two we're going to make it tick John Harrison became obsessed with incredibly accurate clocks to keep time not on but at sea he lived close to the mighty river Humber where he must have been aware of the stories the sailors brought back this was the beginning of a great seafaring age the British were pushing out across the oceans the trouble was they had a real technical problem with navigation once they were out of sight of land they had no idea where they were and they didn't have the technology to find out sailors learned to navigate by measuring the height of the Sun above the horizon using a sextant not that easy despite the patient instruction of Lieutenant Johnny banister of the Royal Navy so you look at the Sun to start off with yeah and then slowly move your right hand down and move your left hand as well oh I see till the Sun touches the horizon and lost it notice that it's not easing it does not know now here at the boat rocking around but even when you've got it right measuring the height of the Sun doesn't tell you where you are only how far north of the Equator what use was it I mean you know your latitude but you've run away that's all you could work out to find out how far east or west they were sailors used dead reckoning first they had to measure their speed today I'm on the Humber lifeboat and when they aren't saving lives at sea Dave steam Gordon and his crew are pretty handy with a log line so Dave what you got a baked bean Tintin are you going fishing we're going fishing for speed hell okay every 47 feet and three inches we've got a mark on the line which is one knot right we're going to time it for 28 seconds okay and at the 28 seconds will know how many knots have actually gone out by the boat and that represents the speed of the vessel I'll believe it when I see it but Steve's going to throw it over yeah and get it all played out ready to eat first mark see where you go step okay and he'll stop that discuss the staff okay so it's nice stable in the water on my marks Dave you ready one two three go so she's going out freely now right and if you watch the max evil camp the Matt one - this might look a bit basic three but before John Harrison thousands of sailors lives depended on getting this dead right five don't just less than six what was the real answer 5.4 that is amazing really amazing it's so simple it works it really works all right it must be the quality of your baked beans it's got to be like sailors in Harrison's time Johnny is now get a plot our position from the log he knows our speed and from the compass our direction John is plotted our position by dead reckoning but it's not where we are out here River Humber we've got lots of winds and lots of tide actually affect us right and we should have been there we should have been there we measured our speed through the water all right but unfortunately the water itself was moving thanks to the tide errors like this build up on a long voyage they can add up to a ship or even a whole fleet being way off course navigation at sea had always been a problem but it came to public attention after a terrible disaster on the night of the 22nd of October 1707 a fleet of five ships of the line was coming back from Gibraltar under the command of the Admiral of the fleet this splendidly named sir clouds leash of all unfortunately they made a navigational error and they sailed absolutely smack into the silly islands four ships weren't done including the Admirals flagship the Association two thousand men drowned and the Admiral himself was thrown up on the beach half alive and murdered for the ring on his finger this was a truly national disaster and people realized that something had got to be done so in 1714 the government launched the longitude act with a prize of up to 20,000 pounds that's several million in today's money for anyone who could come up with a way to find a ship's position at sea John Harrison thought he could do it with a clock imagine you're a sailor in John Harrison's day sailing from England west towards America now you've been gone for a week or something else a tomorrow out in the middle of the Atlantic and you can tell what time it is where you are you watch until the Sun is that its highest point in the sky and that's noon 12 noon but you don't know where you are however suppose you've taken a clock with you and the clock is set to English time and it says 3:00 in the afternoon then it's quite clear that you're three hours behind England the earth takes 24 hours to turn all the way around and so clearly three hours behind puts you exactly there so you can pinpoint your position using a clock set to English time but there was a problem to be more accurate than the old ways this would need a clock 50 times more precise than any previous clock Matthew read is a clock expert who knows all about John Harrison's wooden clocks he's come along to get precision pendulum number two ticking again but he's got to be careful it's a striking late on it's over 280 years old and the weights that drive the clock could cause severe damage once it's going it's absolutely beautiful John Harrison seems to have made this clock in direct response to the longitude challenge the design is unique but very complicated what's he being over alpha well considering that the contemporary clock maybe by Judge Graham would have kept time to within a handful of seconds a week and Harrison was claiming a second a month then you could argue that in fact he wasn't being verbally right again going back to the longitude problem the Achilles heel of all clocks especially in the 18th century was a lubrication and Harrison knew that if you wanted a clock to run reliably inconsistently see if you can make something that had no added lubrication then you would have solved that problem John Harrison was clearly an unusual man I decided that the only way to get into his mind was to follow in his footsteps and to make my own wooden clock I have to confess I've become a bit obsessed with bodging making things from freshly cut wood using very basic tools this is my shave horse and here is my wonderful homemade kool-aid powered I've been sucking okay I admit I cheated slightly here but then I haven't got quite as much time as John Harrison had a clock has basically three components the first is a wheel which is going to spin round like this one the second is a power source and I'm going to hang on a piece of string this weight which will pull the wheel round as it falls and then we need a time regulator and I'm going to use a pendulum and that's going to swing on this nail the top is a bit of oak and then there's this long piece of ash and a weight on the end and because it's one meter long it will take one second to go from one side of the swing to the other so that's going to be my time regulator now I'm going to move that back at all the pallets these points here are just between the cogs of my escape wheel it should allow one cog to escape on each swing of the pendulum let's just try it and see fantastic this is how John Harrison's clocks worked now I also need to measure how much time has gone by so I'll just stop it for a sec and I'll add this extra wheel here so if I connect the two with a rubber band like this this big wheel with its hand on it should turn around in exactly a minute Harrison flocks were amazingly accurate something like one second a day mine well I need a little bit more practice I think but I have made a clock out of wood John Harrison was certainly a better craftsman than I am but his early clocks had run a similar design and after all if you were making a clock for a stately home it probably didn't matter whether it was all that accurate but something changed in John Harrison he decided that it did matter how accurate his clocks were and thought he knew how to make them much much better he got his chance probably about 1720 when he was commissioning to make a clock for the broccoli at Park estate in North Lincoln Sean the big house here was owned by the Earl of Yarbrough who wanted a cloth for his stable the building's still used as a staple and the clock is still there ah this is it that is a beautiful clock just look at the carving of the minutes on the dial now this is oak this is brass but almost the whole thing is made of wood an extraordinary thing is that it's been running practically continuously for almost 300 years now you're the chap who wins this yes I am that yeah how often we do it once a week can we take the case off and get a better look we can that be right how do we do that helping me get inside the clock is Richard John Smith the broccoli Spears state jointer I thought he looked a bit familiar then I realized that when I visited the top 20 years ago I'd met Richard's dad when he used to look after the clock it is 40 odd years then 40 years yeah and how long have you been doing it and I'm doing it very about five years now you got somewhere to go then yeah you say you wind it once a week could I have a goat whining at night you can write when he first built it this was a completely conventional clock hands like most lots of the time it didn't work very well he was always coming back to fix it things kept sticking kyoya them but in the bitter Lincolnshire climate the oil thickened and gummed everything up so he threw out the sticky parts and came up with entirely new designs the most obvious innovation is this beautiful thing that grasshopper escapement instead of the wood rubbing against the brass it releases it cleanly and where things did have to rub he used an amazing new material a dark wood from Africa called lignum vitae lignum vitae is very oily wood and it's dim drill to self-replicate you mean you don't need toilet nap there's no lubrication this needed never now in 300 years that has extruded but there was a surprising twist to the tale not only was the new clock maintenance-free it was incredibly accurate no longer losing a minute a day it now lost much less than a minute a week what an amazing clock oil no friction - no problems but 300 years the extraordinary claim made for John Harrison is that he built the most accurate clock in the world and then used it to help mariners find their position at sea which was one of the great problems of the age this would have been pretty extraordinary if he'd been a grand scientist living in London and armed with all the latest precision equipment but in fact he was a humble joiner who lived and worked here in the village of Barrow on tumba John was born in West Yorkshire but the family moved here when he was a young lad and it was here in Barrow that he and his younger brother James set up their business there aren't many relics of the Harrison's left in Barrow but one of them is this sundial and if you look at it it says 1732 something church it might be her the Trinity Church and they made it and presented it to the church and look at the time the shadow points - 1 X 9 o'clock it's absolutely spot-on perfect timekeeping there really isn't much more of John Harrison in Barrow local knowledge says that this pub car park wall was once John's workshop if that's right I'm standing in the very spot where he built not only the Leeds clock but the first of his great marine timekeepers later he moved into a combined house and workshop up the road sadly the house itself has now gone but there is a much older house opposite and John said he set his clocks by timing when particular stars disappeared behind his neighbour's chimney Matthew you've been having fun here don't you take the whole thing to bits I have yeah great fun yeah was it easy yes it was it follows a pattern of any 18th century long-case clock in the vast majority of parts right and putting it back together yeah just a question of time really it can only fit together in one order it's all even I couldn't even you could fit together if I give enough time yeah I'm not talking about no million-dollar question yes why did he build this clock well by the mid 1720s he was actively seeking the longitude prize the cash prize to buy an longitude at sea and in these clocks he tried to develop systems that could be used later in his marine timekeepers and they were temperature compensation and the ability to run without lubrication he'd solved the lubrication problem in the broccoli part clock but to make clocks that would work in all temperatures he turned the house in Barrow into a lab so you mean he actually put one in a hot room and one in a cold room he did yes yeah absolutely he would build up the fire in one room and have the other one maybe I don't know in the north-facing room or something and then swap them around right so what was he testing there I was temperature compensation okay Maureen time keeper anytime keeper in fact before Harrison would run slow in heat and fast in cold and he wanted to eliminate a problem in order to win the larger prize matthew hasn't taken the clock apart just for fun they want to find out how John Harrison made his amazing wooden gear wheels so they brought them to the Royal Armouries in Leeds where they can take a look inside the great wheel from the Leeds Club is actually made of many separate pieces of oak of different sorts and an x-ray may reveal what John Harrison was up to the x-ray shows a master at work mixing fast-growing and slow-growing oak and lining up the grain for maximum strength matthew has also brought along a new toy it looks like a ray gun and that's pretty much what it is firing x-rays at the surface decoration on the clock to find out what it's made of it's faded now but the case may have been decorated with gold and silver leaf at one time this sort of testing used to mean sending the piece away now you get a result in seconds we were obviously on a piece that was originally silver leaf and we're picking up areas of gold which would have been gold leaf it was probably decorated to make it more saleable once he'd used it John so precision pendulum number two to raise funds for further research the longitude prize was to be awarded by a board of longitude which included the astronomer royal here is where Harrison had to present his clock this is the Royal Observatory Greenwich built in 1675 and one of its main functions is the accurate measurement of time today the time galleries at Greenwich are a shrine to the amazing clocks John Harrison made to attack the longitude problem even though precision pendulum number two was the best talk in the world it was not going to win the prize no matter how good his clock was a swinging pendulum was never going to work on a ship at sea working away in Barrow and Humber this is what he came up with and you can see that the pendulum has gone completely it's been replaced by these arms that swing out and in and this motion was designed to cope with the awful rocking of a ship at sea the Board agreed to a see trial Harrison and the clock was sent on a return trip to Lisbon he got horribly seasick his clock was a bit erratic on the way out but easily beat the ship's navigators on the way home it was good but not conclusive he moved to London eventually here to Red Line square in Hoban where he spent the rest of his life pursuing the prize in London he made a second and then a third great Marine timekeeper it was a radical new design unfortunately he could not get it quite right and he went on fiddling and tinkering with it for 19 years but in the 1750s Harrison now a professional clock maker got interested in watches there were not great timekeepers losing a minute a day was considered good but being John Harrison he went back to basics and radically rethought the way watches were made finally aged 67 he presented the board of longitude with this his solution to the problem h4 84 was the result of Harrison's life work and a brilliant timekeeper but the board of longitude said that it did not meet the conditions for the prize they insisted that copies of edge 4 should be made and tested so that there would be timekeepers for the entire Navy in 1772 a copy of edge 4 was given to Captain James Cook who took it on his second and third great voyages Cook was won over calling the watch our never failing friend but the board wouldn't agree that the trial was over luckily the King George the 3rd was a great fan of these marine timekeepers and even had them tested in his own observatory he heard that Harrison and the board of longitude had fallen out and he personally intervened and said that enough was enough and Harrison should get the money well eventually they did pay him some when he was 80 years old and he died three years later at the end of the road turn right John Harrison solved the longitude problem over 200 years ago but his idea of using time to find where you are lives on I've been using my satellite navigation system to find my way around and there's a direct link between John Harrison and sat-nav it also uses incredibly precise clocks to pinpoint your position on earth you have reached your destination to show you how it works I need some nautical help so I recruited the boys at Hull Trinity House School which has been preparing lads to go to sea since the 18th century satellite navigation involves sending clocks into space those clocks are accurate to within one second in a million years I wonder if even John Harrison would have believed such a thing was possible I've set up my own sat-nav system I want to find out my position in this vast ocean I've set up three satellites man by students from Hull Trinity they're slightly low-tech each one has a loudspeaker and a mobile phone connected to the Speaking Clock now what I'm doing is watching my clock here which is synchronized with a speaking clock and when it comes up to a particular time at ten seconds I press my stopwatch and I listen for the speaking talk over there and when I hear the third pip I press it again and look for the difference between the two the sound from each station takes a while to reach me the further away the longer it takes now from station a over there the difference was point six four of a second and from station B over there the difference was 1.6 eighth of a second so it's obviously much farther away now oh really now this session see in real sat-nav the signal travels at the speed of light but I don't think I could work my stopwatch quite quickly enough for that one point three six or C so I've now got four delays from all three stations for a it's 0.64 of a second and that means I'm should have been somewhere on that Ark there station B was one point six eight and so I must have been somewhere in this arc here so probably I was where these points cross but as a check I can do station C and they were about here so I'll take the third arc and result is I must have been somewhere within that triangle there so that gives me a small area in which I know I am but that's how GPS works by taking the time from three different satellites they can pinpoint your position in your car and I can do it on a boat frozen in the middle of the lake John Harrison started his quest to build the most accurate clock in the world because it would help to save lives at sea today clocks are still saving lives at sea so Dave tell me how you know where we are where we're going well straightaway I know where we are because we've got the GPS oh this is GPS those GPS opposition down to what a millimeter well you can see it's to one thousandth of a mile and it's updating all the time so constantly update amazing GPS is then put it on the chart you can see the boat on the chart so this is an electronic show electronic chart Nick arrive anything on East knows that's that's was live before John Harrison navigation was so inaccurate that ships frequently hit rocks and many lives were lost today thanks to Harrison's ideas Dave and his crew have a permanent readout of exactly where they are I love this machine it may look just like a an old grandfather clock but I've had the privilege of getting under its skin seeing how it ticks and unraveling the stories both table position pendulum run - and of its makeup John longitude Harrison what's really amazing is that Harrison's big ideas are still making waves today precision pendulum number two made in Barrow and Humber in North Lincolnshire really did change the world if you have an object which shows what the people and places in the UK have given the world then you can add it to our digital museum to find out more go to BBC dr. dot UK / a history of the world

Channel: leedsmuseums

Views: 416,082

Rating: 4.822619 out of 5

Keywords: John, Longitude, Harrison, Clock

Id: T-g27KS0yiY

Length: 29min 1sec (1741 seconds)

Published: Wed Aug 22 2012

Reddit Comments

[u/sacundim]

This is a remarkably accurate and well-explained video on John Harrison's clocks and watches. I could only find these points to criticize:

1. Harrison's Precision Pendulum Clock #2, that they show on the video, is clearly missing its original gridiron pendulum, but the video doesn't mention it. The pendulum shown in the video has only one rod, which makes it an obvious modern replacement, presumably made with an alloy like Invar that didn't exist in Harrison's time.
2. The video makes it sound like Harrison came up with the idea of using clocks to tell longitude at sea, when the idea had been around for 200 years already.
3. The video takes for granted Harrison's claim that his pendulum clocks kept time to within 1 second in 90 days. This is in fact controversial; some modern commentators find it plausible, some do not.
4. As so many popular materials do, the video arguably takes Harrison's side a bit too much. Harrison proved that a watch could be made accurate enough to determine longitude at sea and pioneered a good chunk of the key technologies (bimetallic temperature compensation, lubrication-free escapements, maintaining power mechanism), but most of his designs proved to be dead ends. The same principles (and a few others) had to be incorporated into much simpler timepieces redesigned from scratch in order to produce practical, mass-manufactured and cost-effective marine chronometers.