The British Empire's Resilient Subsea Telegraph Network
Key topics
Delving into the history of the British Empire's subsea telegraph network, commenters are uncovering fascinating tales of global communication infrastructure that once spanned the globe. Personal anecdotes abound, with travelers sharing stories of stumbling upon remnants of the network, such as telegraph buildings and museums, in unexpected locations like Valentia Island and Alice Springs. As commenters explore the All-Red Line, a remarkable feat of imperial engineering, they're struck by the realization that even ancient civilizations had their own forms of long-distance communication, like smoke signals. The discussion is a captivating blend of history, travel, and technology, revealing the lasting legacy of the British Empire's ambitious telecommunications projects.
Snapshot generated from the HN discussion
Discussion Activity
Very active discussionFirst comment
1h
Peak period
23
0-6h
Avg / period
9
Based on 63 loaded comments
Key moments
- 01Story posted
Dec 30, 2025 at 8:10 AM EST
9 days ago
Step 01 - 02First comment
Dec 30, 2025 at 9:25 AM EST
1h after posting
Step 02 - 03Peak activity
23 comments in 0-6h
Hottest window of the conversation
Step 03 - 04Latest activity
Jan 1, 2026 at 10:37 PM EST
6d ago
Step 04
Generating AI Summary...
Analyzing up to 500 comments to identify key contributors and discussion patterns
Want the full context?
Jump to the original sources
Read the primary article or dive into the live Hacker News thread when you're ready.
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.)
Its last iteration in the late 1950s was CANTAT, COMPAC, and the TransCanada Relay. CANTAT-1 linked Newfoundland and Scotland. COMPAC linked BC in Canada, via Hawaii and Fiji, with Australia/NZ. It opened in 1962 with 80 phone channels. One of the last reflections of the old way of thinking about empire.
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.
The Netherlands was too far away from the courts in Spain for them to govern effectively. Travel time was measured in weeks. So, remote regions like that necessarily had a large degree of autonomy. That became the basis for power to centralize around Amsterdam as it was favorably located for for trading. There were a lot of grievances with religious issues (Catholicism vs. Protestantism), taxation, etc. But the Spanish failure to project power from a distance had everything to do with the centralized nature of their empire and long communication channels.
In the so called golden century (17th century), the Netherlands got filthy rich on global trade and expansion. Information and knowledge flowed to and from Amsterdam from all over the world.
The Dutch naval forces dominated the North Sea for quite some time and it's only later that the British emerged as the better/bigger empire. Navies and ships were the fastest way to move information around at the time. Until the British finally upgraded to cables and telegrams which enabled them to have colonies on all continents. They really nailed command and control across their empire for a while.
The Romans had their roads to move armies and information. Shipping and navigation technology leveled that up from the 1400s or so. These days, low latency communication is a commodity of course.
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.
[1] The legacy of undersea cables:
https://blog.sciencemuseumgroup.org.uk/the-legacy-of-underse...
[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.
Paved the way for the downfall of physical money, and over a century of warfare in the absence of any sort of monetary discipline.
Thankfully we now have the necessary tool to fill that vaccuum.
When the pound replaced the Spanish silver dollar as the default global currency, it did so with a nascent international banking system where banknotes issued by a certain bank in a certain location could be exchanged by other banks in other locations.
Payments were thus often settled in metal rather than being transacted with it.
This is a fascinating thread of world history by the way. I knew the Spanish had a huge role in global trade but I just never learned much of the details.
Most of those Spanish dollars were minted in Mexico. After Mexico became independent they continued to issue silver dollars in the Spanish pattern. That it was the global currency is no overstatement. The Mexican dollar was the de facto currency in late 19th century China, a pattern long-established by then from the Spanish silk trade.
I was surprised to realise bank notes used to be tied to a bank, not a state.
There were major wars for millenia before the invention of the telegraph. They even names like "The Hundred Years War".
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. 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.
The ultimate goal of humanity should be UBI and all humans living a content, peaceful life in which they can pursue the things that interest them.
But because of evolutionary behaviours that result in things like capitalism, we'll never reach that goal. I'll say it now: humans are currently biologically incapable of sustaining a true utopia.
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.
Eg. when the London-Mumbai telegraph was new it took around 45 minutes in one direction.
[1] https://www.wired.com/1996/12/ffglass/
[2] https://news.ycombinator.com/item?id=46433901
Aha! OK, after a quick search on Wikipedia I can see that that did in fact happen:
https://en.wikipedia.org/wiki/Electrical_telegraphy_in_the_U...
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
edition.cnn.com/2024/12/30/europe/baltic-sea-cable-anchor-drag-russia-intl-latam
https://www.sciencemuseum.org.uk/objects-and-stories/robeson...