There's a phrase I didn't think I'd be reading today
When was the last time you appreciated a sundial? I'll give you a mo... Nothing? We could be seeing even less of the ancient time-telling method as those with the knowledge to build sundials pass on. Seventy-six-year-old Dr Frank King, a fellow in computer science at Churchill College, University of Cambridge, has told the …
"I am a sundial and I make a botch of what is done much better by a watch."
But he also wrote
"Here in a secret place forgotten, I mark the tremendous progress of the sky. So may your inward soul, forgotten, mark the dawn, the noon, the coming of the dark."
To be fair, analogue watches don't work in the dark either.
They came up with a solution to that 120 years ago.
When (through error via trial) Radium was discovered to be radioactive and somewhat harmful when the people painting were licking the stuff off the paint brushes, a variety of less lethal substances were used to replace it commonly known as glow in the dark paint, and more recently electroluminescent paint.
Radium was discovered to be radioactive and somewhat harmful when the people painting were licking the stuff
Also to a generation of small children who wore them in bed - especially those who liked to sleep with their shiny watches close to the lower groin area..
(testes/ovaries and radiation don't mix kids - Just Say No)
Reminds me of a Bloom County where Oliver builds a working nuke for a grade school science project. The fissile material was scraped off 9700 glow in the dark watches.
Anyone wants to see it, go to comics.com and look for Bloom County by Berkeley Breathed for December 28, 2010.
"To be fair, analogue watches don't work in the dark either."
Yes they do, they glow in the dark. Have done for a very long time.
Also there have been analogue watches that have a backlight around for long enough that you can buy one for your kid:
Here is another analogue watch that sets the time by itself from a radio broadcast powered by an atomic clock, this also lights up in the dark:
As that one too expensive? Here is one using Indeglo, a backlight trademark that came out in the 90's:
So yes, analogue watches work in the dark and have done so for a number of decades.
Most good analogue watches use Luminova these days - it absorbs solar radiation and uses a phosphor to make the hands visible for several hours. Tritium used to be the norm*, and this had the advantage of working even after a month in a cave. However, it was banned* because of fears of exposing watch repairers to a radioactive dust.
* Any watch with ' T Swiss Made T' is one that used tritium, but the half life is such that the luminosity is reduced after about ten years. Plus, the tritium's energy eventually degraded the phosphor into dust - not good for the delicate gear cogs.
** A loophole used by some watches is that 'tactical equipment' can use tritium, but it needs to be contained within little glass vials
since all MECHANICAL clocks and watches use an escapement, they are essentially digital, counting ticks. Analog clocks would be water clocks or high precision candles. Or a sundial. I do not think any of them are suitable for wearing on the wrist or carrying in the pocket.
have a look at the Seiko spring drive movements in their Grand Seikos. The movement is run overspeed and braked electronically...
I say, "have a look" as it's the closest most of us will get for obvious (£) reasons...
The patent-pending tfb night-o-matic sundial also works in the dark: you merely need to cut away the chunk of the planet which is occluding the Sun. Our luxury leather-plated 'evil genius' edition comes with free giant lasers with which to do the cutting. Sharks and mountain lair extra.
Yeah, but a pinhole sun image is very small for a ten foot long ray, perhaps thumb size. I tried this once, and was disappointed in the small image, so I arranged to bounce the sun ray back and forth inside the room using mirrors, yet the sun image was still only about three inches wide, with very low brightness. But sunspots were clearly visible. It's kind of a trip to view sunspots with no lenses involved.
I remember being taught by Frank King to how to log on to the mainframe and compile my first Fortran program. I'm not sure if I ever met him in person, or whether I just remember a series of short video clips of him showing how it was done.
Dr. King is also a well-known figure in the world of bellringing --- the only sport for people who like permutations and group theory.
He is the University Bellringer, Steeplekeeper of the University Church, Keeper of the university Clock. I'd be happy with any one of those titles but to have all three is awesome.
Unless he acquired them in a Ponder Stibbons sort of way... "this obscure post needs filling, who can we assign it to?"
>I have one in my garden, which doesn't belong to the National Trust.
We've got a couple in the garden. A little one on a pedestal that gives a digital display and a big one on a wall that's a standard vertical dial with a gnomon. The wall one is quite large and keeps pretty good time according to the nearby radio corrected clock.
The problem with sundials is that they don't work that well indoors in an office environment or in cars. You also can't easily interface them with computers -- its possible but a bit pointless since the computer is likely to be able to keep better time than the sundial.
Euclidean geometry is a mathematical system attributed to Alexandrian Greek mathematician Euclid, which he described in his textbook on geometry: the Elements. Euclid's method consists in assuming a small set of intuitively appealing axioms, and deducing many other propositions (theorems) from these.
Oh, we have a sundial in the garden attached to a heavy lump of concrete that gives the local yoofs an instant hernia when they try and nick it after a drunken night out :-)
Have to admit, I thought Euclid was the ancient greek bloke that worked out the diameter of the earth with nothing more than a stick and a hole in the ground. (Turned out to be Eratosthenes - thanks wikipedia)
Anyway, I am always impressed by ancient boffins working out stuff like that.
Ancient boffins were no less intelligent than modern ones, there were just fewer of them and they didn't have the resources of modern society to draw on.
Even so, the Antikythera Mechanism would require some very skilled craftsmen or modern machinery to replicate. If the Romans hadn't thought that military strength and slave labour was better than Greek intelligence, the industrial revolution could have come an awful lot earlier and Jesus might have entered Jerusalem on a steam tractor.
If the Romans hadn't thought that military strength and slave labour was better than Greek intelligence
Given that the Romans were technically a lot more advanced (and the Greeks also had both military might and slavery) this is a bit disingenuous..
(The ancient Greek philosophers were very much of the 'thought experiment' mould - very uninterested in practical mechanics. Add the fact that most of them were from the 'gentleman' class and, as such, had a huge aversion to manual labour, it's unlikely that their materials science and technology would have increased terribly fast.)
 With obvious exceptions like Hero..
There's a theory that a lot of the engineering knowledge the Greeks theorised about was actually swiped from the Egyptians (or other Middle-Eastern cultures like the Assyirans), who'd actually worked out these things in practice. Archimedes' Screw being a classic example.
Getting more or less incomplete reports of certain mechanisms from such places and trying to make sense of them would account for the mixture of practicality and weirdness that the Greek philosophers seemed to embody.
I was once asked if I had any interesting/humorous suggestions for the title of a chapter on Euclid in a math primer a friend was writing.
I suggested "Here's looking at Euclid."
He went with that after shouting at me that he'd been working on a pun title for over two days and come up mostly dry.
I suggested "Here's looking at Euclid."
I'm not accusing either party of plagiarism - such things get conceived independently - but I remember this same joke/pun being used on a Radio 2 comedy show about 15 years ago, "The Ape That Got Lucky". It was part of a list of books supposedly written by the guest academic on the program...
"Here's Looking at Euclid", Geometry In The Films Of Humphrey Bogart
"Pop Goes The Weasel - A Treasury of Vivisection Anecdotes"
...being the only two I can remember.
Would the death of sundials really be that terrible? Not only are they imprecise to read (oo, erm, is it 11:31 or 11:32? YES, IT'S IMPORTANT)
Well, actually if you make them too accurate, they'll point out how inaccurate our current time is. Famously, it was the introduction of railway timetables that forced standardisation of the meridian at Greenwich on us; Bristol is about eight minutes behind if memory serves. However, depending on where you are in the world, the classical design may be of little utility if you don't have a lot of direct sunlght, like much of the west side of the UK. But then again, being accurate to the minute is perhaps less interesting than watching time change in the course of the year so that when the sun starts to rise over point X, is a good time to start planting.
I'm a big fan of having analogue and/or non-networked timepieces even though I have a plethora of digital devices using different techniques (NTP, mobile networks, radios) to synchronise and find it funny that they often have several seconds of drift. And then there is digital broadcasting…
Unless you live in a time zone subject to periodic shifts due to Daylight Saving or whatever. Trying to reset a dial clock hung high up on a wall where the adjustment knob is normally concealed by the wall is no fun.
Incidentally, I actually decided to make my own GPS-disciplined NTP server (so while I still use networking, it's on the LAN so doesn't depend on the Internet to work) using a Raspberry Pi 3 and an Uputronics GPS HAT. It's been a fascinating exercise, and I'm right now working to add on one of those little OLED displays to display time and status.
Famously, it was the introduction of railway timetables that forced standardisation of the meridian at Greenwich on us;
Really? I'd always thought it was because we needed a way to stop ships crashing into places because they didn't know where the hell they were, and that we'd had the meridian long before we learned how to weld a boiler.
Learn summat every day.
I'm sure the cross wasn't angled at 45° - I hope - it needs to be an angle equal to the latitude.
About large sundials, Cassini (the astronomer) build a meridian in the cathedral of Bologna which is 67 metres long. A hole in the ceiling 27m above projects the sun disc on it at midday - this kind of sundial isn't used to tell the hour, but to measure the length of the solar year, and will tell the day of the year (including equinoxes and solstices).
I may in the past have spent some time watching the hours pass on the giant sundial outside the office of a former employer
55.934076, -3.314049 (Lochside Place, Edinburgh)
Then again, this is Scotland, so I can't have spent THAT many hours watching the Sun (and my office didn't overlook this part of the grounds)
Perhaps ironically for this item, spherical geometry is a non-Euclidean geometry. However the science of sundials is in fact a branch of projective geometry, which is different again, being classed as neither Euclidean nor non-Euclidean (mathematicians - don'ch'a love 'em?). We have Euclid to thank for his geometry, the likes of Gauss, Bolyai and Lobackevski for the existence of the non-Euclidean, and a whole shedload of brains culminating in von Staudt and Klein for the projective formulation. That a fellow philosopher from my old College should not make this clear must surely be down to the work of trolls.
I can read an analogue clock.
I can build a sundial. I can even align it properly by several different means to make it more than accurate enough for everyday use.
And yet, every clock in my house (with the exception of one that's there to look pretty) is digital. And any time I reference the time, I use a digital display. The only "analogue" timekeepers in my house that are ever used are the time dials on the microwave and the egg timer. Even then, that's because the digital egg timer I bought was too quiet so it's useless, all I had otherwise was a spring/clockwork one, and the microwave was cheap.
In work, everything is synchronised to GMT to within a second or so. I mean, everything. Wall clocks, phones, computers, access control. Why that would be any other way in a modern workplace, I can't imagine, because you just plug the NTP settings in and off you go.
I hate watches now (phones are my time source now), but I have spent half my life with a Casio digital watch on my arm because one glance tells you day, date and time without any interpretation required. And if you bought the right model, it was MSF too.
I literally have one clock to change when the summer time idiocy takes effect - that's to that analogue clock. Sure, I can get MSF versions of it but it's not worth it as I never refer to it.
Basically, to me a clock has to be a) synched, b) numbers you can read quickly, c) unambigious (AM/PM), d) have alarms you can set on it.
Now if we could just sort this "60 minutes to the hour, 24 hours to the day, 28-31 days in a month, 365.25 days to the year" imperial-like shite, then I'll be a happy man. Pick a time base, stick with it. Hell, we have no need to tie it to local noon or even the orbit of the planet any more. Just pick a timebase and stick to it, and then you *calculate* things like sunrise and sunset just like we have to do now, but with some sensible numbers.
I was traveling the back roads of Cheshire last week and stopped to get a few pics of a pub named The Cock, ( tee hee to my American friends) , and it has a sundial mounted vertically on the wall about 15 feet up, had never even contemplated a vertical sundial before, but yes, it works!
It is my understanding that part of the education of a gentleman was the ability to tell the time to within fifteen minutes by looking at the sun. Then the pocket watch and later the wrist watch came along and the need disappeared.
Icon because how else would you know it was time to head to the pub?
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