These Clocks Helped Measure the World 

Keith is a legend. Amazing to hear him tell these stories with Adam. Thanks Keith, and Adam!

"Longitude" by Dava Sobel is a great book about the development of reliable time devices and the reason they were so desperately needed.

Harrison, the guy who invented the marine chronometers invented also the bimetallic pendulum as well ( actually he made the first usable one since the idea predated him). He fine-tuned his pendulums by having one in freezing cold (in the winter) and another one near a fireplace at full blast

11:33 The "chain drive" is called a fusée. It compensates for the diminishing torque of the mainspring as it winds down maintaining the rate regardless of changes in the drive force.

Adam, as much as I love your build videos; I must say that these type of museum show and tell videos are the icing on the cake! Love the the Royal Society series. Cheers.

I love Adams curiosity, fascination, enthusiasm and knowledge he brings to these videos. He has a tremendous respect for the objects and their history, and I believe that the Royal Institute recognizes those qualities and shows him the same respect. It's wonderful to see.

The Marine chronometer was invented by John Harrison in 1735. The chain is referred to as a "Fusee" (invented in 1525). Early spring/metal-alloy technology was still in its infancy and spring driven clocks from the era had the issue of running fast on a full wind and running slower as they unwind. To fix this they had these cone shape tracks for a chain to run on (with some clever math) to counteract that. (Think of it almost like a CVT transmission.) These chains were often hand built and assembled by orphans to earn their keep. These were very small parts and they needed people with good eyes and small hands. Lots of history there. (Keep in mind the industrial revolution didn't start until 1760'ish.)

For those not in the know, Brady Haran has many a youTube channel, including one called Objectivity which deals with objects or other works at The Royal Society

I was just watching another RU-vidr talking about how the method for determining your longitude was found, and how much the Royal Society was involved. It really was some interesting science and interpersonal drama LOL I wish this series of Adam at the Royal Society would never end! More and more just keep showing up! Adam talking to museum folk never gets old, please keep doing more of these! And more of Adam creating something for the museums too. Did he create something for the book binding museum? I was so amazed at the machine that creates ledgers. Keep up the awesome work!

The purpose of the changing radius on the chain drum is to offset the reducing torque produced by the mainspring as it unwinds.

I've wound hundreds of clocks in my lifetime so far, but I've never seen anyone so excited to wind a clock as Adam. I'd love to have him visit our clock workshop at some point.

A few years ago, I saw a collection of chronometers at Greenwich ... and to me, the most noticeable one was slightly battered as it was the actual one that Shackleton had taken on his rescue voyage from Elephant Island to South Georgia ! Absolutely amazing piece of history !!

As a navigator, this was even more fascinating to me than a lot of your amazing content. When I'm at sea, besides the nav system, I have an independent GPS tracking Apple Watch and two very accurate Timex IronMan watches that I consult. Nowadays, the other watches are really just to make sure GPS time (which all mariners use these days as their timestamp) is accurate to your position.

I love this kind of content! It combines science, engineering, technology, craftmenship, history, exploration, and the human spirit into a captivating story. Thank you, sir!

Fascinating. Folks interested in the development of accurate timekeeping could read Dava Sobel's "Longitude" - it focuses on Harrison's work.

The chain drive is wrapped around the spring barrel in a tapering helix. A wound up spring exerts a lot of force, so the chain starts in a track with a wide radius. As the spring unwinds, its pull reduces, so the helical track's radius diminishes to allow consistent tension on the chain.

I love old science stuff. This was so cool to see. I hope I'm able to get a one on one tour of the RS some day. Im a physics major so its not 100% impossible that they will want me there some day lol.

I spent many many hours as a child in the clock room at the Greenwich Maritime Museum in London after school, just watching John Harrison’s superb chronometers… And although they are works of art in their own right, it was the obvious tiny modifications, alterations, and tool marks that told the real story of their development…

When I hear Keith talk I always am looking for Brady. But I cannot get enough of Keith and the Royal Society stuff. - cheers

This series feels like a cover album of Objectivity's greatest hits (in a good way). Bet the treasure chest is next.

I’m honoured that you paid a visit to our shores, dear Adam. GOD bless you.

These Royal Society videos are just fascinating!

I've always loved these sort of mechanical clock mechanisms (the ship's clocks). I've been dying to be able to find a good replica of these sorts of things (so i can use them and handle them and examine them without fear of damaging something historic) along with a few other types of mechanical clocks. These things are just absolutely marvels of engineering and manufacturing!

Wonderful! I hope you have another segment showing and talking about John Harrison's work at creating the first clock able to solve the problem of Longitude. It's an amazing story! It blows my mind that those craftsmen were able to build such accurate timepieces with little more than simple hand tools.

Really interesting. Enjoying these visits

I just find every one of these Royal Society videos fascinating

Great to see all these important timekeepers. FYI the Regulator is a clock for use on land, it was developed by George Graham around 1725, his later clocks were made by Shelton. This one is fitted with a Harrison bimetallic pendulum. The two 'Chronometers' by Arnold here are two of his earliest known productions and are experimental. These were for use on the sea in order to determine longitude and they immediately followed Harrison's highly complex but successful timekeeper 'H4'. Arnold, not Harrison was in fact the inventor of the 'Chronometer' , a term invented by him in 1779. His was a completely different machine to Harrison's and importantly, could be produced in numbers. Arnold's patented inventions became the basis for both the precision watch and the later Marine Chronometer. Between C.1780 - C.1795 just about all the marine chronometers used on ships were produced by him.

This was awesome to watch.

One correction - when they arrived to make their measurements, they established true time by taking observations of the Moons of Jupiter. They made tables that accurately predicted when a moon would move behind or in front of Jupiter, and could establish time, and know the rates of the clocks and chronometers from there. They needed the chronometers at sea because you needed a high magnification to observe Jupiter that accurately, and you couldn't establish that on a moving ship. But if the chrometers stopped, say, because of an unreliable midshipman, and you were near to shore, you could take your telescope, land, and take the needed observations to re-establish the time. The big regulator clock is needed because the occultation of a Moon of Jupiter might happen days or weeks before your scientific observation, so you needed to maintain the time you established. You might also want to confirm and refine your established time by making multiple observations over multiple occultations.

I'm sure that Technology Connections Alec would be very excited about the bi-metal mechanism in this video. In fact, legend has it that if you utter the phrase "Bi-Metallic Strip" three times in a row while holding a rice cooker, he will instantly appear in front of you like Beetlejuice.

i can only imagine they film like 4 different videos each day he's there, so they have to greet each other at least 5x a day lol

The chain is called a fusee, it wraps around the “fusee cone” which is a tiered cone which was used to level out the torque from the mainspring as mainsprings of this period weren’t made as consistently as they are today, it essentially works the same way gears work on a bicycle. It succeeded the stackfreed which was another attempt at providing more consistent torque to the escapement, which was essential for the type of escapement this chronometer used.

I love time keeping even though time is not real. I see you have an Apple Watch. I have the Apple pocket watch(aka iPhone). You have other watches SKX and such. Please do a video showing your watches or other timing devices. Thank so much for the years of education and entertainment. Love MB’s and your channel.

Very, very cool Adam!!!!!

I saw some of those working clocks during my trip to Greenwich Observatory in 2014.

Thank you 😊

I wanted to learn something new this winter, and I learned how to repair clocks.... I have more than 20 ticking in my house now, and have done a few for others. It's really fascinating!

This guy has a fantastic voice and way of speaking , very friendly and welcoming :) Two grayfoxes marveling old timers :P pun intended

they look like brothers

"I mean, then, slicing time into precise increments is literally like, one of the oldest human endeavors." That was beautiful. You should study up on fusees. It's a fascinating method for equalizing power for a spring wound watch across the duration of the wind. In watches, the chains were made by children in many cases because adults had trouble with vision and fine motor skills.

Remember those pop quizzes in school that you felt totally unprepared for? That's how this curator feels about Adams questions. Lol. But he's doing great

Awesome video

It feels like you are on cooks ship with the filming in this video

Adam really ought to go see the Harrison clocks at Greenwich. Wonderful things.

It's true what they say that people usually end up looking like what others expect people in a particular career to look like.

The chain drive on the two small chronometers is called a fusee. The purpose of the fusee is to compensate for differences in power when the spring is fully wound and when it has run down. You probably noticed that one side of the chain is on a cone and the other side is a cylinder. The cylinder side has the mainspring, when fully wound the chain is fully on the cone.

Feels like an episode of "The Antique Roadshow"

I had the opportunity to work in a clock tower on a school in northern Illinois some years ago (installing first gen .11 2.4/5 Ghz transceivers). It was a pendulum clock that, as far as I know, is still functioning. I was threatened with torture and pain of death if I so much as looked at it sideways. There were two small stacks of coins covered in a century worth of dust that were the "Fine Tune" balance/adjustment. I follow a watchmaker's channel, Wristwatch Revival, and still find the precision fascinating.

The title alone made me instantly think of the Harrison 2

I would love to see a meeting between this fellow, Keith Moore, and Bill Nighy… Nighy played bowtie-wearing museum tour “Dr. Black” in the Musée d'Orsay - the Doctor Who episode “Vincent and the Doctor”. It would be epic!! 🌼

There's an excellent docu drama about Harrison, with Michael Gambon. It's free on RU-vid or was the last time i checked. Adam Hart did an excellent program as well. And more importantly, Only Fool's And Horses...

The legend of Keith continues!

I had a clock like that at my childhood home

I'd be willing to bet Adam has an awesome watch collection and owns at least one Accutron.

Timekeeping is still incredibly important in ship's Navigation. GPS positioning is all about time keeping. The satellites have incredibly accurate clocks onboard (corrected for relativity too), and broadcast the exact time and their exact orbital data. Your GPS receiver in turn receives all these different times, and in turn can work out the distance to each of the satellites, where exactly each satellite is at any given time, and thus figure out where the receiver is. On ship, other kinds of fixings are also all dependent on when the fix was taken, as the ship is always in motion. So even hundreds of years after Harrison, it still all comes down to time.

Time really flew by while I was watching this video.

Am I the only one that wants to sit with Keith and listen to him speak about.... ANYTHING? Anything that reminds him... "...Oh yes we have one of these things over here... and oh that reminds me of this thing... and this thing... and this person, and that event...." i want to be a part of his ' stream of conscientiousness'.

Hamilton Watch Co of Lancaster, Pennsylvania won the contract to produce ship’s chronometers for US Naval vessels in WWII.

Thought that was Bill Nighy for a sec there haha! 😆

Accurate timekeeping is taken for granted now, but it was hugely difficult and incredibly important for a great many scientific disciplines. Not to mention navigation. Hell, modern GPS is based almost entirely on super accurate timekeeping.

The Marine Chronometer looks like the mechanism of a 18th Century Pocket Watch.

1:44: Mixes up regulators (very precise pendulum clocks, like the John Shelton at the beginning of the video) and chronometers (very precise oversized balance wheel clocks, like the Arnolds later in the video) 3:48: Adam says one metal expands as the other contracts with temperature... but of course both metals expand with temperature! The trick is that one metal expands more than the other for the same temperature change, but the gridiron pendulum arranges the rods so that one metal expands downward and the other upward. Wikipedia has a good diagram: en.wikipedia.org/wiki/Gridiron_pendulum 6:20: That topic of how they managed to travel the sea with a clock like this packed up is magnificently illustrated in a video that Dr John Taylor has posted here to RU-vid of another Venus transit regulator, this one by Ellicott, in which video Dr. Taylor demonstrates how the case in that one was specifically designed for transporting it. In fact I wonder if the case in this Shelton regulator is original, Dr. Taylor's video of the Ellicott Venus transit regulator illustrates for example how that one's case had brackets built in to secure the pendulum bob during transport: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-DrIDtoDAzTs.html 9:27 and 13:32: A crucial bit of context that's missing here is that during Cook's voyage marine chronometers were still experimental devices. These two Arnold chronometers and a few others were sent literally as a practical test of the concept and the specific designs. Arnold's chronometers in fact as I recall worked poorly in that trip, but the star of the show worked out to be Larcum Kendall's copy of Harrison's H5-the Board of Longitude wasn't happy just yet to award Harrison the Longitude prize unless a second watchmaker like Kendall could actually construct one on their own. The primary time standard in the field for this voyage would have been astronomical observations with the observatory set up at the destination-use the sun to establish what the local time is, and the time of the transits of Jupiter's moons to establish the Greenwich time (they had printed almanacs saying at which dates and times they would happen). Using marine chronometers as the time standard and taking three on board so you could tell which was the bad one when one malfuctioned really only became standard procedure some 25-40 years later-at this point they were still in the process of inventing practical marine chronometers! In the meantime during these trips they were also testing out on-ship methods based on observing the moon with sextants (the lunar distances method). 11:37: The question/answer sequence makes it sound like the fusee chain is bimetallic and involved in the temperature compensation, but the bimetallic compensation is not in the fusee chain, it's a different part of the watch. 12:04: The reason the chain is wrapped around the barrel is because as the mainspring unwinds it pulls through that chain on another part called the "fusee" that acts as a sort of continuously variable transmission to change the leverage between the mainspring and the chronometer's gear train. The reason for this is that as the mainspring winds down its torque falls, so the fusee changes the gear ratio continuously to even out the force that is transmitted to the rest of the mechanism. It actually isn't exception that this chronometer had a fusee and chain, it used to be a standard feature in spring-driven clocks and watches; searching for "fusee clock" or "fusee watch" will turn up lots of examples (although often they used gut lines instead of chain). 12:50: There was indeed been a lot of handwork into making chronometers, but these Arnold chronometers specifically were part of the process whereby other watchmakers were working out simpler alternative designs to Harrison's pioneering but baroquely complex chronometers, and therefore leverage the established watch and clockmaking industry to manufacture them in bigger numbers. In fact, this ties up with what I mention in my 9:27 note above-this is why Arnold's chronometers were sent on Cook's voyage, to test alternatives to Harrison's design. As I mention above, Arnold's chronometers performed poorly on this trip, but by the 1780s he'd settled on a good design almost like what became standard in the 19th century. Again, these two Arnold pieces are not standard marine chronometers, they're part of the historical process that led from Harrison's pioneering chronometer of the late 1750s to the technologically mature chronometers of the 1780s and onward.

Keith is like Adam's British twin brother.

this would be a really nice object to get a 3d model of, or a x-ray scan. so that you could really look at the internal mechanism. I'm personally curious about the function of the chain

Welp! now chris clickspring knows how we all feel watching his videos :D brilliant.

I want one of Adam's flashlight.

I see Adam has “dressed up” to visit the RAS. 😄❣️

Doesn't "the regulator" specifically denote that each degree (seconds, minutes and hours) of the timing is being displayed on a separate dial and axis (tho in this case only the sweep dial is separate, and the axis is the "same" as the minutes, or rather is coaxial with the minutes one)?

A man with one watch always knows what time it is. A man with 2 watches is never sure..

On Cook’s voyage to Tahiti (and NZ and Australia) the navigator messed up and both clocks stopped after the entered the Pacific by Chile. Cook was furious and reset the clocks using his own internal mental clock and that navigator never made that mistake again.

Clock content FTW!

Apologies for straying way off topic, but does anyone know what flashlight it is that Adam pulls out at @11:19 to look at the ships timepieces?

Someone get Keith to start his own channel please!

Was the big clock mounted on a gimbal on the ship to keep it from rocking?

Why do the seconds not line up exactly.

Your best video to date, but as an engineer and a horologist I am biased, thank you.

A shame he didn't mention the maintaining power on the clock. The pin that was pushed down to be able to wind it not only opens up the winding hole, it also acts a driving force on the clock train, keeping it going. When a clock is wound, all tension is removed from the train and the clock stops for a few seconds (until it is wound). These clocks werr so accurate that this would actually make a difference. After maybe a minute or two the winding hole cover would come down again. This cover was to stop you from accidentaly winding the clock without engaging the maintaining power.

What material is used for the clock face? Looks like brushed and polished aluminium, which it clearly can't be given the age of the clock. Perhaps something ceramic?

They look like long lost brothers

I really wish there was someone making true replicas of some 18th C. marine chronometers. :(

Notice how Adam is keeping one or both hands behind him; classic "don't touch' behavior.

Finely some thing about clocks again, still waiting for videos about watches...

Are these things even COSC certified?

I'm sorry I have to say something. He's wearing those purple gloves so he can handle artifacts without seriously contaminating them from things like dirt, dead skin cells, and oil from his hands. THEN HE SHAKES HANDS while wearing the gloves, contaminating them with Adam's hand dirt, skin cells, and oil, then immediately handles the artifacts. (and it was SO much worse in the video where he just immediately started handling that telescope!) Are any other conservationists here in the comments also screaming at the screen right now?

This Keith guy looks like you would think a guy like him would look like.

That clock needs some attention. The second pointer is a bit off.

I thought Brady Haran looked weird at first.

It's only a clock if it chimes... otherwise it's a timepiece My father was a Watchmaker to trade, technically a scientific precision engineer one of two at Timex, Dundee, Scotland,1946 when they first started, and were called UK Time He was offered a job in New York by a senior partner... my mother wouldn't let him 😂

😂 I'm a fan of clocks and regulators...they are also an inside joke for time travelers.😂👍

Does the length of the pendulum really matter? I thought the period of a pendulum was the same regardless of the length.

You still in London

it's not really that surprising that people were able to make something like that by hand if you think that people have been making intricate jewelry for a lot longer which uses a lot of the same processes like working with sheet metals, shaping small details in symetrical patterns, etc.

At 12:41 Am I the only one thinking how Catastrophic that would be if he dropped the mechanism and it bounced off the table, over the Abyss, and to the floor below? 😱😁 Mike in San Diego. 🌞🎸🚀🖖

With a bit of training, you might have a stunt double!

Stop shaking his hand, Adam. He can't use those gloves now. 😛

Slightly painful to listen to two non clock experts getting it not wrong but also not completely right. For instance no ship's chronometer is ever wholly original, in use they will have been serviced every time the ship docked back at home port, often the ones in use being swapped out and serviced ones replacing them. A service might entail replacement of worn parts, replacement of that fusee chain and mainspring, and rebushing of pivots. Many saw service for a hundred years and became a Trigger's broom with parts replaced wholesale. For this reason Harrison's H4 at Greenwich is not run, to preserve the 'as made by Harrison' condition.

I have my volume all the way up and can't understand him

Sup

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