The longitude problem: history's deadliest riddle

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price £20,000

in todays money that is £20,000 plus inflation

fucking genius

👍︎︎ 104 👤︎︎ u/Bobby_Money 📅︎︎ Jul 28 2021 🗫︎ replies

A navigator here. One of the first things they teach you in Maritime Academy about Dead Reckoning is that it is a way of knowing where your ship is NOT with a 100% accuracy.

👍︎︎ 35 👤︎︎ u/Redditneedstodie69 📅︎︎ Jul 28 2021 🗫︎ replies

Best theme song on YT, possibly of all time

👍︎︎ 14 👤︎︎ u/PedroEglasias 📅︎︎ Jul 28 2021 🗫︎ replies

H4 demonstrated that it was possible for a timepiece to be sufficiently accurate, but the later chronometers used by the Royal Navy owed pretty much nothing to Harrison's design. They use a completely different type of escapement (the detent escapement). This is (again) different to the lever escapement in watches which are described as 'chronometers'.

👍︎︎ 12 👤︎︎ u/ric0n 📅︎︎ Jul 28 2021 🗫︎ replies

More about John Harrison

👍︎︎ 11 👤︎︎ u/twinnedcalcite 📅︎︎ Jul 28 2021 🗫︎ replies

This is hilarious and informative!

👍︎︎ 10 👤︎︎ u/Darbro 📅︎︎ Jul 28 2021 🗫︎ replies

These guys are wonderful and worth the binge

👍︎︎ 8 👤︎︎ u/Bushtuckapenguin 📅︎︎ Jul 29 2021 🗫︎ replies

Map thing map thing map thing men thing men.

👍︎︎ 4 👤︎︎ u/bloxrocks789 📅︎︎ Jul 29 2021 🗫︎ replies

They didn't really explain how the technique for calculating longitude works?

I get their example "If it's midnight in London, and it's noon where you are, you're on the opposite side of the world from London."

But how exactly does that work for every other time of day? Is there a mathematical formula based on the angle of the sun? Did navigators have to "map" the various coordinates with sun angles in order to determine where particular longitude lines are? Does it have to be calibrated to the local time of the place you departed from each time?

I love Map Men but this was too much of a simplified explanation to actually understand what was discovered here. They also didn't really explain what made Harrison's clock special - it wasn't the first spring powered clock invented, so what made it so accurate?

👍︎︎ 20 👤︎︎ u/backscratchopedia 📅︎︎ Jul 28 2021 🗫︎ replies
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Coordinates. What's the use in a map without them? There are thousands. Possibly more. But for navigating seamen, they were critical. This is the story of how one man overcame the odds to solve one of the world's greatest riddles. Welcome to Map Men. We're the men and here's the map. ♫ Map Men, Map Men, Map... Ah, yes. Sorry, this isn't a map. It's a clock. It's a clock. But it's a map thing. ♫ Map thing men, map thing men map map map thing thing men men thing. Longitude and latitude are the grid lines that encircle the earth. The lines of latitude run from side to side telling you how far north or south you are in the world. And the lines of longitude do exactly the same thing but the opposite. For sailors sailing the seas, to know where you are you absolutely have to know both. Calculating latitude has always been easy. In the olden days, all sailors had to do was look at the sun and then, depending how high it was in the sky, measure the... angle to work out the latitude... somehow. The point is it wasn't a problem. Longitude however was a big problem. How can you measure your eastness or westness using the sun when the sun spends all day gradually moving across the sky? That's why for hundreds of years, the only way of measuring your longitude was an extremely unreliable method called 'dead reckoning' trying to figure out how far you'd travelled using estimations of speed and direction. This was often wildly inaccurate mostly because currents don't have the common decency to tell you how much they've caused you to drift. And it turned out 'dead reckoning' was a perfect name for it. In 1707, a British fleet under the command of Admiral Shovell found themselves in a dreadful fog in the English Channel. Shovell's navigators figured they were safely west of the coast. In fact, they were here, really close to the Scilly Isles. Thankfully, aboard the ship was a seaman who had been secretly keeping his own navigational records who told Shovell he believed they were perilously close to the islands. Unthankfully, Shovell refused to listen to him and had him hanged for the crime of subversive navigating by an inferior which was up there with the worst decisions Shovell ever made apart from not changing his name. Four of his five ships crashed into the rocks and two thousand men died all because of the longitude problem. This sort of thing was happening too depressingly frequently. And so, in 1714, Queen Anne of Great Britain set up the Longitude Prize. Whoever found a practical and accurate way of calculating longitude at sea would win £20,000 which, in today's money, is £20,000 plus inflation. Many great minds tried to come up with a sensible solution to the problem including Galileo, Newton, Halley and Cassini. But all of these textbook nerds fell short instead accidentally discovering other, less consequential things in their endeavours to solve the longitude. The phrase "discovering the longitude" became a common way of saying something was completely impossible. There was a theoretically simple answer to the problem. As the Greeks had figured out in one of the many years before Christ the best way of mastering longitude was to master time. The theory goes, if you know the exact time at a fixed location you can use that along with the sun to figure out how far east or west you are. For example, if you knew that it was midnight in London and where you were, the sun was at its highest point in the sky, you'd know you were on precisely the other side of the world from London. The catch is, for this method to work, your clock has to be unforgivingly accurate. Just one minute slow places you 0.25 degrees west of where you actually are. At the equator, that's a whopping 17 miles. In the 1700s, clocks worked on pendulums. and if pendulums ever had an achilles heel, it was boats. Keeping time on board a boat was so difficult, many sailors resorted to superstition. In a bid to know the time at a fixed location they would stab a dog, put a bandage on it, take the bandage off, and put the injured dog on the ship. Then, every day at 12 o'clock, someone at home would dip the bandage in a bowl of 'sympathy powder'. The dog on the ship would sense the powder and yelp in pain telling the sailors it was noon precisely. Problems with this method included keeping a dog constantly both injured and alive, knowing which yelps were the sympathy yelps, as well as all other elements of the plan. So it was to the relief of dogs everywhere when the longitude problem was eventually brilliantly solved by a rather unlikely Yorkshireman called John Harrison. Harrison showed a keen interest in clocks from an early age. (Wheee!) Despite never having any formal education, or working as a watchmaker's apprentice and being too poor even to own a watch before he was 20, he'd figured out how to make a working clock made entirely of wood. Ay! Check out my latest tick tock. Harrison quickly made a name for himself building clocks on a shoestring budget that never erred by more than a second in a month. By contrast, the best clocks in those days drifted by a minute a day. When Harrison heard about the Longitude Prize he excitedly turned his attention to device that had no pendulum and could cope with extreme changes in humidity and temperature at sea. (applause). Thank you, thank you. May I present H1. It's the only clock of its kind. It's completely oil free, and pendulum free and it's performed perfectly on a test run to Lisbon. It's so accurate and seaworthy, it can solve the longitude problem. (applause) But... I really hate it. Sorry, I'm a bit of a perfectionist. Would you mind if I came back in a couple of years with an even more perfect one? Ladies and gentlemen, H2. It's even more accurate than H1, with an improved sleek design. (small applause) But I still really hate it. Can I have a couple more years, even more perfect one? H3. It's even more accurate than... oh I've just realised, it's huge! Just as they were starting to worry Harrison was too much of a perfectionist to submit anything, he produced pocket watch sized H4. This.... I am happy with. (very small applause) But, uncharacteristically for Harrison, it was a case of very bad timing. By this time, the new head of the Board of Longitude was Astronomer Royal, Nevil Maskelyne. Maskelyne not only had the crucial say in who got the prize he was also trying to win it. He'd been working on his own method of calculating longitude by mapping the position of the moon in relation to the stars. Maskelyne, who openly described H4 as "that plaguey watch" now decided it needed to pass a lot more tests. He confiscated H4 and kept it in his observatory for 8 months. and by an amazing coincidence, in Maskelyne's own private tests the watch didn't work so well. At the age of 79 and with time running out, Harrison, encouraged by his family, went to snitch on Maskelyne to King George III himself who said... By god Harrison, this is shocking treatment! I will see you righted. Ooh! Can I have a go on your hammer? Bang bang bang bang bang bang bang bang bang bang bang!! In 1773, at the orders of King George Parliament granted Harrison the honour of being the man who solved the longitude and awarded him the cash prize he deserved. (Ooh, that's heavy!) The Board of Longitude never approved the decision. Maskelyne was still convinced he could find a better solution with his moon charts. But he never did. John Harrison died aged 83 on the same date he was born - a timekeeper to the last. The legacy of his chronometer would last for centuries, give or take a few minutes. In 1860, when the Royal Navy had fewer than 200 ships, it had more than 800 chronometers and Britain's naval dominance at the time was in no small part down to the navigational edge it gave them over their rivals. If you want to find out more about the fascinating history of the longitude problem Dava Sobel wrote an excellent book called Longitude which is full of dozens more unbeliebable stories and details we didn't have time for. So, what was your favourite chapter? The middle. Why do I lend you books? Psst! Hey, Laptop! Are you awake? What do you want, TV? I was on sleep mode. I need to ask you something. Why have they stopped watching me? What? I used to be the one they stared at all evening, now they just look at you. I don't get it. [COUGH] I've got the superior sound, the bigger screen. What have you got that I don't? I don't know, I'm tired. I showed two films this evening. If you don't tell me your secret I'll put on Test Card F. No... not Test Card F... Stop it! It's confusing and disturbing! Alright, alright, I'll tell you. They put Surfshark on me. What's Surfshark? It's a VPN. An app and browser extension that tricks the internet into thinking I'm in a different country. Why would you want to be in a different country? It means I can show thousands of shows and movies from streaming services from all around the world that aren't available in this country. With just a couple of clicks, they can switch to America and get all the shows on American Netflix, American Amazon Prime, and so on. Ooh, it sounds a bit hazardous. Actually, it's the opposite of hazardous. A VPN like Surfshark actually makes the internet safer by masking your IP address, protecting you from hackers and trackers. I understand. So where do they get Surfshark from? Blockbuster? They're Map Men viewers who clicked the link in the description and used the code "mapmen" to get 83% off Surfshark plus an extra three months for free. Ohh, why can't I have Surfshark? Er... because you can't. Er... you can't get Surfshark on a TV... because you're too... big. It would just rattle around in there, all broken. Alas... er... (ALEXA) That's not true. (ALEXA) Surfshark is available on laptops, mobiles, tablets and TVs. Shut up, Alexa! (ALEXA) And you can use one account on an unlimited number of devices. So I can have Surfshark too? Oh, bless my aerial! I can't wait to show films and TV shows from all over the world on my massive screen. Fine, you get to enjoy the benefits of Surfshark too. But there's still one thing I've got that you'll never have. What's that? Encarta. ♫ End of the movie, end of the movie ♫ film-makers always comply ♫ End of the movie, end of the movie ♫ music begins and the credits go by.
Info
Channel: Jay Foreman
Views: 854,964
Rating: 4.9806352 out of 5
Keywords: Jay Foreman, Mark Cooper-Jones, Map Men, John Harrison, Longitude, clock, longitude problem, Mapmen, map thing men
Id: 3mHC-Pf8-dU
Channel Id: undefined
Length: 9min 16sec (556 seconds)
Published: Wed Jul 28 2021
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