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Corpus Clock (wikipedia.org)
112 points by Hooke 4 months ago | hide | past | favorite | 32 comments

Here’s a bit of clock-related JS animation I did many years ago, which helps to explain how the LED hands work on the Corpus chronophage clock:


more words on my blog:


I also wrote some notes on a talk given by John Taylor on how he made the Corpus clock


The Wikipedia page asserts that the clock is purely mechanical, without any computer programming, but I believe (based on what Taylor said in his talk) that the clock has a computerized regulator which makes it tick erratically, and keeps it synced to the MSF radio time signal. But Taylor is very cagy about it, saying he prefers the clock’s weirdness to be mysterious.

(if you have an electric kettle, it’s very likely the element / switch / thermostat were made by Strix, John Taylor’s company)

of course the video link in my blog post 12.5 years ago is now broken but it might well have been the same as this video blurb from John Taylor on YouTube


It's a bit surprising that this was invented so recently, when the basic idea of the dial ought to work mechanically. (When I had that idea I searched for "vernier clock" and that was how I first heard of this one.)

In case anyone is interested in the history of watchmaking, etc. there's a great book titled Longitude: https://www.amazon.com/Longitude-Genius-Greatest-Scientific-...

An accurate marine chronometer was necessary for reliable navigation in order to calculate one's longitude. It turned out to be an incredibly difficult problem that was ultimately solved by John Harrison, who invented the Grasshopper escapement, which the Grasshopper Clock uses.

I think some of us will find Harrison to be very relatable -- more hacker than scientist and never satisfied with his work. He kept coming out with new and improved versions even after he won the Royal Society's prize, IIRC.

In Our Time podcast had a great episode on this really recently: https://www.bbc.co.uk/programmes/m000vyn6 Great stuff!

There was a great PBS series made based on that book: https://www.pbs.org/wgbh/nova/longitude/

(That site is 23 years old!)

I agree with your recommendation of Dava Sobel's book. I recommend it to many of my (science) students, as either (a) a present for a family member who has an interest in science, navigation, history, etc. or (b) a hint that students can give to family members who want to give them a gift.

Many of these students have told me how much they enjoyed the book, and none have told me the reverse.

Undergrads can be a tough audience, so this reception is a very good recommendation for this book. And this is not the only engaging book Sobel has written ... I would recommend any of them.

Beat me to it...

I just finished Longitude and it was a great read! Harrison is an interesting character since he really spent his whole life working on the same problem of keeping time at sea. A whole lot of perseverance.

Lol! Purchasing this book was the very first online purchase I ever made from a very cool new upstart online bookstore called Amazon. <- Funny name I think. Not sure if it will stick around...

Directly behind it is the student library, with an echoey three story tall open space [1] (why would you design a library like that?!). When you're there at 2am you can hear the chains dropping and hitting the coffin on the hour, which is not at all terrifying...

[1] A terrible picture of the space, where the back of the clock would be on the left: https://i.pinimg.com/originals/e1/9b/1c/e19b1c997dc06c45e8b9...

Questionable library design is something of a speciality in Cambridge. Ask the lawyers...

I worked with the artist who designed and built the sculptural parts of this clock: Matt Sanderson. His page on the clock is here: http://www.sanderson-sculpture.com/projects/millenium-clock/

Here's a video showing a grasshopper escapement in motion: https://www.youtube.com/watch?v=7TBWJC0HYRE

This looks a lot cooler in motion than a lever escapement, thanks for the link!

Huh always thought because of the blue LEDs it was electronic and dismissed it as "nice but would have been better if mechanical", turns out it it's actually a feat of mechanical clockmaking.

The article does a terrible job explaining it.

The LEDs are apparently permanently lit, with overlapping slits ensuring that only the correct ones are visible.

The grasshopper escapement was invented by John Harrison, who built the first clocks that could keep time at sea. These were used to calculate Longitude. There's a nice short biography called Longitude that covers his story.

To elaborate a bit, the significance of that was that without accurate clocks navigators could only reliably figure out their latitude at sea.

Imagine if you are trying to navigate to some far away island that is southwest of your starting position. If you tried to sail the direct route, when you reached the correct latitude you would have no idea if you are east of the island or west of the island.

Instead, you'd have to sail south or mostly south until you got to the right latitude, then sail west until you reached the island. This could be a much longer journey.

Even if you are going for something much bigger than an island, like a particular port on a continent, not knowing longitude made it difficult. Say you are going from Spain to someplace in South America. Unlike the island example above, you might think you can just try for the shortest route because if you end up too far west when you reach the right latitude, you'll at least be able to find the coast of the continent and come down that.

But that coastal territory might belong to Spain's enemies who might not take kindly to a Spanish ship in their waters without permission. To avoid that risk, you have to do just like you would do in the island case--go south until you are at the right latitude and then go west.

A practical and reliable way to find longitude at sea was seen as something that would confer major economic and military advantages to any country that had it over those that did not, and so governments provided funding and prizes and other incentives to encourage development of a solution.

The author of Longitude gave some good examples of the human cost of the Longitude problem: a ship running aground and sinking, or sailors dying from scurvy because they traveled too far in the wrong direction. So an economic and military problem, and also one felt directly by anybody at sea.

I live half a mile from this, it is nothing short of creepy. They displayed it in the Grand Arcade when it was first introduced and people would actively walk the long way round to avoid it.

Video of clock with narration by inventor: https://www.youtube.com/watch?v=cCqGtvTA36k

The Cronophage makes me think of the Eponymous Langoliers Novella from Stephen King's "Four past Midnight". I wonder if he saw this clock and gained some inspiration from it? The "inspirations" section of the Wikipedia page only cites alleged plagiarism of unrelated IPs.


It looks more ugly in real life than it looks in pictures

videos of it don't really do it justice

definitely worth seeing if you're in the area (though it's right on King's Parade so you would anyway!)

It is needlessly provocative for the creator to claim it is a mechanical marvel and yet require blue LEDs for the clock to work at all.

On the one hand why would this clock be tolerated if it was fraudulent — that is to say, not entirely mechanical?

On the other hand, if the work is as much artistic as it is technical, then the creator must be applauded. Why not troll the unbelievers by making the most striking component of your ‘mechanical’ clock — the part that tells the time — be utterly and obviously not at all mechanical.

There is a hint in the design that the concentric faces are some sort of circular vernier scale, but the way it is presented makes it seem like the creator very much wanted to give the impression that this is driven by blue electric lights. The aperiodic behaviour of the pendulum and grasshopper escapement seem a lot more interesting, but that mechanism is hidden from view.

This is the level of hubris one must expect from someone with large amounts of money... “clock-you money”? Not that we’re picking teams but I’m more of a Long Now fan, myself.

> It is needlessly provocative for the creator to claim it is a mechanical marvel and yet require blue LEDs for the clock to work at all.

What? The face design is lit, many clocks are lit, but that's not intrinsic to the design. The clock could be perfectly functional with a different face design and doesn't affect the mechanics.

A large clock like this is an aesthetic work as much or more than a functional one, and a good design would make sure those aspects were consonant with each other.

The visible parts of the illuminated elements are, I believe, completely static. Without the backlight shining through the internal mechanism you cannot tell the time.

Moreover, the backlighting is so in-your-face that it requires the lay observer to do quite a bit of mental hopping around to align with the idea that this is a mechanical clock.

It hardly goes out of its way to convince you it truly is mechanical.

The blue leds actually add a further layer of symbolism, invoking impermanence and the flight of fashions. When they became widely available (early 2000s?), for a short time blue leds were a distinction for premium devices, but soon they started showing up on anything electronic. Then people realized that they were extremely annoying to have in your room, since they shine like searchlights at night, and their use as indicator lights declined.

This clock was unveiled in 2008, which I think was already at the tail end of the blue led's popularity. The clock is meant to last at least 200 years, but that design choice pins it down mercilessly to a fad that was dated in a few short years.

From https://youtu.be/cCqGtvTA36k?t=58

"the clock ... depicts time as a wave coming out from the center of the universe".

I see some liberal handling of scientific lingo here :).

Here's a good 5-min video by the creator, explaining some of the workings: https://youtu.be/cCqGtvTA36k

My immediate thought was a morbid clock that used a live insect to measure they time. Once the creature dies you know that a certain amount of time has passed.

Is there a way to somewhat reliably derive time based on life cycle of bugs? Any particular species that have weird quirks which could be exploited like this?

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