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.
One of the major uses for the telegraph was the first funds transfers that could happen quicker than moving paper (or bullion) from one location to another. London banks would telegraph correspondent banks in India, Australia, etc.
This essentially doubled the capital intensity of international trade since the goods had to move in one direction but the money could be sent instantaneously in the other.
That book led me to Gutta Percha, the plastic-like coating on the wires used in these cables which was quite the innovation and made this all possible. Vulcanized rubber was the other option but performed poorly in cables and was harder to work with.
The above is a fascinating and depressing history of the Gutta Percha factory that made all these cables, after joining with the cable company that supplied the actual wires. There's an 1853 travelogue piece embedded here of an author visiting the factory, where he notes in the worst parts of the factory where boiling and heat are applied, it was staffed with boys who barely made more than a dollar a week. By boys I thought it was slang for young men then I realized 1850s England was heavily using child labor.
Those cables are the product of child labor, like much of the Victorian age's industrial and textile output. Children often made up significant portions of factory workforces, sometimes 25-50% in certain textile sectors, with many under 14. I wish the stories of child labor were better told and more prominent. This abuse and exploitation of children gets quite whitewashed during this age and its nice to see it acknowledged, albeit briefly.
At least in the UK the fact that the Victorians and others used a lot of child labour is well and widely known.
Blake wrote the poem The Chimney Sweeper about boys sold into the trade long before the 1850s and Elizabeth Barrett Browning published The Cry of the Children in Blackwood's magazine in 1843. Charles Kingsley used his The Water Babies to question child labour and England's treatment of the poor in general in 1862-3.
No one with any pretensions to knowledge of those times can claim not to know about child labour.
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.
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.
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.
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.
They also got a tiny fraction of the rubber from cutting a whole tree down due to not finding a method to get all the rubber, and so cut almost all of the trees down
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.
It was strategically important in WW1 because the British could communicate with the colonies with very chance little chance of messages being intercepted. The Germans, in contrast, didn't have access to their own transatlantic channels and had to use plain-text messages on cables that the UK/US controlled (US operators disallowed coded comms).
The Cable that Changed the World (2024) is pretty nice on the topic. Shows us how, again, most of the things we consider "new" or at even revolutionary most showcase how historical ignorance.
If you enjoy this, you might like to read about the Zimmermann Telegram - British SIGINT that took advantage of this network, bringing the USA in to World War I.
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.
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.
... 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
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.
Ok, how does that work though? I understand the concept of lower attenuation since air/vacuum has less molecules to get in the way. Less repeaters, should have less system latency.
What I don't understand is how light is moving through what is a hollow bendable medium. Is the tube that it's in reflective and there's just less time it's passing through it? I guess that's the main one in commercial use to shave some time off, reading about it here: https://en.wikipedia.org/wiki/Photonic-crystal_fiber
[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...
This essentially doubled the capital intensity of international trade since the goods had to move in one direction but the money could be sent instantaneously in the other.
https://atlantic-cable.com/Article/GuttaPercha/
The above is a fascinating and depressing history of the Gutta Percha factory that made all these cables, after joining with the cable company that supplied the actual wires. There's an 1853 travelogue piece embedded here of an author visiting the factory, where he notes in the worst parts of the factory where boiling and heat are applied, it was staffed with boys who barely made more than a dollar a week. By boys I thought it was slang for young men then I realized 1850s England was heavily using child labor.
Those cables are the product of child labor, like much of the Victorian age's industrial and textile output. Children often made up significant portions of factory workforces, sometimes 25-50% in certain textile sectors, with many under 14. I wish the stories of child labor were better told and more prominent. This abuse and exploitation of children gets quite whitewashed during this age and its nice to see it acknowledged, albeit briefly.
Blake wrote the poem The Chimney Sweeper about boys sold into the trade long before the 1850s and Elizabeth Barrett Browning published The Cry of the Children in Blackwood's magazine in 1843. Charles Kingsley used his The Water Babies to question child labour and England's treatment of the poor in general in 1862-3.
No one with any pretensions to knowledge of those times can claim not to know about child labour.
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://en.wikipedia.org/wiki/Zimmermann_telegram
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.
https://youtu.be/zmyBSrQodnI?si=OpFZhiQeNn3ax58p
https://www.sciencemuseum.org.uk/objects-and-stories/robeson...
Eg. when the London-Mumbai telegraph was new it took around 45 minutes in one direction.
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.
Ok, how does that work though? I understand the concept of lower attenuation since air/vacuum has less molecules to get in the way. Less repeaters, should have less system latency.
What I don't understand is how light is moving through what is a hollow bendable medium. Is the tube that it's in reflective and there's just less time it's passing through it? I guess that's the main one in commercial use to shave some time off, reading about it here: https://en.wikipedia.org/wiki/Photonic-crystal_fiber
Also the way fibre works is commonly misunderstood. The light isn't bouncing.