I always have to recommend Mother Earth, Mother Board by Neal Stephenson[1] if the thought of undersea cables sounds at all interesting. I'll also second andyjohnson0's recommendation of The Victorian Internet[2] - it blew my mind how much of modern digital culture existed on telegraphs prior to voice.
An interesting book on the subject of telegraph networks is The Victorian Internet by Tom Standage [1]. As well as the technical and commercial drivers, it also describes how the telegraph forced people to confront concepts like simultaneity, information being distinct from its physical medium, privacy, early approaches to encryption, etc. A fascinating book.
The GBP/USD currency pair is still known just as "the cable".
Aside from all its other uses: the telegraph gave a way to synchronize clocks. And accurate time is accurate measurement of distance.
> [...] The latest determination in 1892 is due to the cooperation of the McGill College Observatory at Montreal, Canada, with the Greenwich Observatory. [...] The final value for the longitude of the Harvard Observatory at Cambridge, as adjusted in June, 1897, is 4h 44m 31s.046 ±0s.048.
I've recommended that book on this board before. If you read it, I'd be curious about how you think it hits now, because part of its interest - I'd say insightfulness, at the time, but it now might risk anachronistic "charm" - was noting similar emergent behaviors between telegraph operators and early internet adopters. The technical content won't have dated, but the social parts may have.
When visiting Ayers Rock in Australia I stayed in Alice Springs. While I was there I learnt that Alice Springs exists because it was a repeater station for a telegraph line that stretched from Southern Australia all the way to London. There would be people listening to morse code, and tapping it out again to the next repeater station. Blew my mind that there was a wire that went all the way to London from Australia!
In the late-1700s/early-1800s the Admiralty Telegraph was used to relay messages between London and Portsmouth (70 odd miles apart) using a semaphore type system with repeater stations every 10 miles or so.
In Tasmania, you can still see at least one semaphore station on Mt Nelson, which is above several suburbs on the south of the city of Hobart. I believe there was a semaphore route from the capital to Port Arthur (convict prison) and possibly other routes over the state too.
Yes, the Uk (southern England in particular) is dotted with "Semaphore Hill"s or "Telegraph Hills"s. There's one very close to where I'm sitting now, a few miles NE of Portsmouth.
To think it was done even 1000s of years prior to that with just smoke and fire! Granted, the ability to communicate through the rain would be a necessity for the British.
My wife and I were visiting County Kerry in SW Ireland last summer. We were on Valentia Island and quite by chance walked past the telegraph building where the first transatlantic cable came ashore. Only marked by a (very interesting) plaque describing its significance.
... an era bookmarked at the end by the first live music broadcast transatlantic performance of Old Man River from a studio in NYC to a theater in London and that wasn't until 1957 and is a story all on its own
Seeing the telegraph cross Canada like that reminded me of the network of hotels across Canada that were used by the wealthy on their way to the Orient from Europe during a bygone era.
I love stories like this! Neil Stephenson has a great wired magazine article about information technology of that time, and telegraphs. The article is kind of a precursor to the ideas in his excellent book cryptonomicon. You should stop what you are doing and read that wired article. And then cryptonomicon if you haven't already done it. Best book to read over the rest of our holidays.
The book and the article are fascinating explorations of the impact of technology and cryptography on the world. The people who did the work to invent and build these worldwide systems were just like us (hackers, inventors, technologists), and we are just like them in a way. We all stand on the shoulders of giants.
Also I can't believe that article is 30 years old, boy I'm old.
Over long distances, fibre optic would have lower latency so it'd be shorter if taking the same path today. But these signals would likely have been morse code and sent one-way at a time, so latency wouldn't have been noticed unless the repeaters were people rebroadcasting the signal (no idea how that was done).
I should have definitely qualified that statement. Technically, electrical signals over copper are "slowed down" less than light through fibre optic cables. However there's attenuation, electromagnetic interference, and other signal loss for electrical signals that (for long haul cables) will mean you will need repeaters that add significant amounts of latency. On top of that, the higher you try and up the frequencies, the worse these problems get.
For some medium-haul stuff, it wouldn't surprise me if you saw copper still being used for lower latency (eg between datacenter sites for flash-trading), but otherwise it's just not economical.
[1] https://www.wired.com/1996/12/ffglass/
[2] https://news.ycombinator.com/item?id=46433901
[1] https://en.wikipedia.org/wiki/The_Victorian_Internet
Aside from all its other uses: the telegraph gave a way to synchronize clocks. And accurate time is accurate measurement of distance.
> [...] The latest determination in 1892 is due to the cooperation of the McGill College Observatory at Montreal, Canada, with the Greenwich Observatory. [...] The final value for the longitude of the Harvard Observatory at Cambridge, as adjusted in June, 1897, is 4h 44m 31s.046 ±0s.048.
-- https://adsabs.harvard.edu/full/1897AJ.....18...25S
71.12936 W; give or take about 2 metres: https://www.bing.com/maps/?v=2&cp=42.38148%7E-71.12936&style...
Before the telegraph they used to do things wirelessly: https://www.brunningandprice.co.uk/_downloads/telegraph/tele...
(Not quite London to Australia though...)
In the late-1700s/early-1800s the Admiralty Telegraph was used to relay messages between London and Portsmouth (70 odd miles apart) using a semaphore type system with repeater stations every 10 miles or so.
https://www.utas.edu.au/library/companion_to_tasmanian_histo...
Sadly the semaphore pole itself is gone. The building is still there and was used until 1969.
Unlike normal rubber, it is a type of thermoplastic and it's a popular organic plastic before the petroleum based modern plastic become pervasive [2].
[1] The legacy of undersea cables:
https://blog.sciencemuseumgroup.org.uk/the-legacy-of-underse...
[2] Gutta-percha:
https://en.wikipedia.org/wiki/Gutta-percha
And one of the old cable huts still exists: https://en.wikipedia.org/wiki/Pacific_Cable_Station
(There's also the https://en.wikipedia.org/wiki/Minack_Theatre built into the cliff face nearby.)
(I've been to the theatre a number of times but never convinced my in-laws to visit the Telegraph Museum.)
https://www.sciencemuseum.org.uk/objects-and-stories/robeson...
Article in paywall at https://www.wired.com/1996/12/ffglass/
The book and the article are fascinating explorations of the impact of technology and cryptography on the world. The people who did the work to invent and build these worldwide systems were just like us (hackers, inventors, technologists), and we are just like them in a way. We all stand on the shoulders of giants.
Also I can't believe that article is 30 years old, boy I'm old.
Source that claim, it's well understood the speed of light is around 66% due to refractive index in glass.
It gets weird with telegraph cables and capacitance, wikipedia at least touches on it here: https://en.wikipedia.org/wiki/Speed_of_electricity
For some medium-haul stuff, it wouldn't surprise me if you saw copper still being used for lower latency (eg between datacenter sites for flash-trading), but otherwise it's just not economical.