# Why did the first Transatlantic telegraph messages take so long to transmit? **URL:** \ **Category:** Factual Questions\ **Created:** [May 21, 2009, 5:03pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200 "2009-05-21T17:03:17Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [May 22, 2009, 3:24am UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/21 "2009-05-22T03:24:04Z")
> [@ninja\_batmike\_lincoln](#): > > True, but a successful signal (dot or dash, I suppose) still crosses the Atlantic at the speed of light, right? No. This is not as simple as you think. The line has resistance, capacitance and inductance. Early lines were of very poor quality. Even with high quality modern transmission lines, resistive losses are minimised but the line has capacitance and inductance. [Transmission line - Wikipedia](http://en.wikipedia.org/wiki/Transmission_line) ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [May 22, 2009, 3:27am UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/22 "2009-05-22T03:27:33Z")
> [@Icerigger](#): > > The story of the first Transatlantic telegraph cable is a fantastic story. That such a project was attempted and succeeded in 1958 is amazing. The cable was so large and heavy two ships were needed to carry it. It broke repeatedly so they had to grapple the ocean floor and fish it out multiple times. Sadly the name **Cyrus Field** is almost unknown today. 1958? > [@](#): > > [Transatlantic telegraph cable - Wikipedia](http://en.wikipedia.org/wiki/Transatlantic_telegraph_cable) > > Five attempts to lay it were made over a nine-year period—in 1857, two in 1858, in 1865, and in 1866—before lasting connections were finally achieved by the SS Great Eastern captained by Sir James Anderson with the 1866 cable and the repaired 1865 cable. Additional cables were laid between Foilhommerum and Heart’s Content in 1873, 1874, 1880 and 1894. By the end of the 19th century, British-, French-, German- and American-owned cables linked Europe and North America in a sophisticated web of telegraphic communications. > > Cyrus West Field was the force behind the first transatlantic telegraph cable, attempted unsuccessfully in 1857 and completed on August 5, 1858. Although not considered particularly successful or long-lasting, it was the first transatlantic cable project to yield practical results. The first official telegram to pass between two continents was a letter of congratulation from Queen Victoria of the United Kingdom to the President of the United States James Buchanan on August 16. The cable was destroyed the following month when Wildman Whitehouse applied excessive voltage to it while trying to achieve faster telegraph operation. The shortness of the period of use undermined public and investor confidence in the project, and delayed efforts to restore a connection. A next attempt was undertaken in 1865 with much-improved material and, following some setbacks, a connection was completed and put into service on July 28, 1866. This time the connection was more durable, and increased public confidence resulted when the 1865 cable was repaired and put into service shortly afterwards. > > Whereas previously communication could only happen over ship, the transatlantic telegraph cable sped up communication to within minutes, allowing communication to happen within the same day. In the 1870s, duplex and quadruplex transmission and receiving systems were set up that could relay multiple messages over the cable. In cross-Atlantic currency trading, the pound sterling came to be referred as “cable” and to this day a cable in financial jargon is one million pounds [1]. The great utility of the cable built on itself, and multiple cables were established soon afterward. ---
**Author:** ![whitetho](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whitetho/32/1059_2.png) [@whitetho](https://boards.straightdope.com/u/whitetho)\ **Post date:** [May 22, 2009, 4:11pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/23 "2009-05-22T16:11:26Z")
[books.google.com](http://books.google.com) has a copy of George B. Prescott’s 1860 classic [History, Theory and Practice of the Electric Telegraph](http://books.google.com/books?id=NK83AAAAMAAJ&printsec=frontcover&dq=history+theory+and+practice+of+the+electric+telegraph). Chapter 14, “The Atlantic Cable”, starting on page 179, discusses the 1858 cable, and the struggles they had getting any messages across during its short life. This book was published before the successful 1866 cable was laid, so much of this chapter is spent refuting claims that the whole thing was a hoax. ---
**Author:** ![Arby](https://avatars.discourse-cdn.com/v4/letter/a/8797f3/32.png) [@Arby](https://boards.straightdope.com/u/Arby)\ **Post date:** [November 29, 2012, 4:18am UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/24 "2012-11-29T04:18:30Z")
> [@hammos1](#): > > The signal quality down the first cable was atrocious. The reason the first message took 17 hours to transmit was that even using the most sensitive receiving equipment, it was difficult to discern the morse being sent, and hence they spent a lot of the time going back and forth correcting errors. I just watched a video about this so I signed up to post what it says about this. hammos1’s reply is the best answer. If anybody is interested in watching a three hour video on the history of electricity they explain it in more detail: https://www.youtube.com/embed/13bGsSLkkuc?feature=oembed&wmode=opaque But to paraphrase the video, the message they wanted to send was only 98 words long, but the message was garbled so they had to repeat the message several times, so what was actually sent was much more than 98 words one way. They didn’t fully understand how electricity worked in communication lines when they built the first cable…that was the problem, and the reason why the messages were garbled. Some engineers later figured out the math and used that to build the replacement cable with better specifications. > [@](#): > > As **ninja batmike lincoln** says, the first cable only lasted a few weeks before breaking down completely. According to that video, I’m not sure if it “broke down” or was accidentally destroyed. One engineer thought the way to solve the signal problem was to increase the voltage (which at the time might have seemed logical but we now know it was the wrong thing to do). It sounds like what may have happened is he “fried” the cable with too much voltage. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [November 29, 2012, 4:31am UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/25 "2012-11-29T04:31:41Z")
> [@Arby](#): > > I just watched a video about this so I signed up to post what it says about this. hammos1’s reply is the best answer. If anybody is interested in watching a three hour video on the history of electricity they explain it in more detail: > > [http://youtu.be/13bGsSLkkuc](http://youtu.be/13bGsSLkkuc) > > But to paraphrase the video, the message they wanted to send was only 98 words long, but the message was garbled so they had to repeat the message several times, so what was actually sent was much more than 98 words one way. They didn’t fully understand how electricity worked in communication lines when they built the first cable…that was the problem, and the reason why the messages were garbled. Some engineers later figured out the math and used that to build the replacement cable with better specifications. > > According to that video, I’m not sure if it “broke down” or was accidentally destroyed. One engineer thought the way to solve the signal problem was to increase the voltage (which at the time might have seemed logical but we now know it was the wrong thing to do). It sounds like what may have happened is he “fried” the cable with too much voltage. Ahh, okay. At first I figured you posted this via transatlantic telegraph back in '09. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [November 29, 2012, 6:12am UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/26 "2012-11-29T06:12:02Z")
> [@Keeve](#): > > [http://en.wikipedia.org/wiki/Speed\_of\_electricity](http://en.wikipedia.org/wiki/Speed_of_electricity): “Propagation speed is affected by insulation, such that in an unshielded copper conductor it is about 96% of the speed of light, while in a typical coaxial cable it is about 66% of the speed of light.”… > [@Q.E.D](#): > > …In insulated conductors, the signal actually propagates at the speed of light through the insulating medium, which for typcial plastic insulations is about .5-.8 c. There’s a formula to calculate the exact volocity factor based on the insulation’s dielectric constant which I don’t recall off the top of my head. > > … > [@Half\_Man\_Half\_Wit](#): > > It doesn’t, really – the reason for the comparatively long time it took lies more in the low chance to get anything across at all, than in the speed of the signal in the conducting medium. As **Q.E.D.** already said, the speed of light in a medium is dependent on the medium’s dielectric constant, which describes its permittivity ε, i.e. the way electric fields propagate within it, and also its permeability μ, which is the corresponding quantity with respect to magnetic fields. Basically, c = [sup]1[/sup]/sub[sup]½[/sup][/sub], and real-world speeds may be about half of the vacuum light speed and up, as has already been quoted. I don’t understand. I picture an electric wire with insulator like, in cross-section, a point–the wire, some space, then a circle surrounding the point–the insulator. If only the wire is doing the heavy lifting, why does the insulator matter? ---
**Author:** ![wbeaty](https://avatars.discourse-cdn.com/v4/letter/w/439d5e/32.png) [@wbeaty](https://boards.straightdope.com/u/wbeaty)\ **Post date:** [November 29, 2012, 7:56am UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/27 "2012-11-29T07:56:41Z")
> [@Leo\_Bloom](#): > > If only the wire is doing the heavy lifting, why does the insulator matter? The wire isn’t a (perfect) conductor, instead it’s a long resistor. And the cable acts like a long string of capacitors in parallel, each separated by the resistor. If you connect a battery across the cable-pair at one end, the voltage at the other end rises slooooooolwy. In other words, any sharp-edged dots and dashes will become totally distorted: their higher frequencies are filtered out, and different lower frequencies travel at different speeds along the cable. The same effects made long-distance telephone communication impossible. Oliver Heaviside solved the problem theoretically in 1887, see [Loading coil - Wikipedia](http://en.wikipedia.org/wiki/Loading_coil) ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [November 29, 2012, 1:49pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/28 "2012-11-29T13:49:01Z")
> [@Arby](#): > > According to that video, I’m not sure if it “broke down” or was accidentally destroyed. One engineer thought the way to solve the signal problem was to increase the voltage (which at the time might have seemed logical but we now know it was the wrong thing to do). It sounds like what may have happened is he “fried” the cable with too much voltage. A long-but-very-interesting article [here](http://www.wired.com/wired/archive/4.12/ffglass_pr.html) about the history of undersea cable communication. According to the article, the voltage was eventually turned up so high that it arced through the insulation, creating a conductive path between the wire core and the surrounding sea water. The wire core itself wasn’t compromised, but that arc through the insulation created a short-circuit to ground, so that now no matter how much voltage they applied at one end, no current (and hence no signal) could be made to reach the receiver on the far end of the cable. ---
**Author:** ![Hermitian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hermitian/32/470_2.png) [@Hermitian](https://boards.straightdope.com/u/Hermitian)\ **Post date:** [November 29, 2012, 2:30pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/29 "2012-11-29T14:30:25Z")
> [@Machine\_Elf](#): > > A long-but-very-interesting article [here](http://www.wired.com/wired/archive/4.12/ffglass_pr.html) about the history of undersea cable communication. According to the article, the voltage was eventually turned up so high that it arced through the insulation, creating a conductive path between the wire core and the surrounding sea water. The wire core itself wasn’t compromised, but that arc through the insulation created a short-circuit to ground, so that now no matter how much voltage they applied at one end, no current (and hence no signal) could be made to reach the receiver on the far end of the cable. You beat me to linking that article. And I’ve only had 3.5 years! ---
**Author:** ![Learjeff](https://avatars.discourse-cdn.com/v4/letter/l/94ad74/32.png) [@Learjeff](https://boards.straightdope.com/u/Learjeff)\ **Post date:** [November 29, 2012, 6:33pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/30 "2012-11-29T18:33:53Z")
> [@Leo\_Bloom](#): > > I don’t understand. I picture an electric wire with insulator like, in cross-section, a point–the wire, some space, then a circle surrounding the point–the insulator. > > If only the wire is doing the heavy lifting, why does the insulator matter? An important point assumed but not pointed out above is that it’s not just one wire that matters, but the pair of wires. Between the two wires there is a capacitance. I don’t know the details, but my guess is that the two main factors are the resistance of the wire and the capacitance of the space between the two wires. I further suspect that the capacitance is related to the type of insulation between them as well as the distance between them. I don’t know whether the insulation around the pair matters; if it does I’d like to hear more about that. BTW on a recent thread here someone who knows more than I do about this stuff also claimed that .6c is typical for long distance optical transmission. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [November 29, 2012, 7:06pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/31 "2012-11-29T19:06:07Z")
> [@Leo\_Bloom](#): > > I don’t understand. I picture an electric wire with insulator like, in cross-section, a point–the wire, some space, then a circle surrounding the point–the insulator. > > If only the wire is doing the heavy lifting, why does the insulator matter? Because the wire-insulator combination creates a capacitor (a capacitor is created when two conductors are separated by an insulator - in this case, the other conductor is the shield, or just the surrounding seawater). And, as pointed out above, very long cables can have very high resistance and capacitance, which tends to mess up the signal integrity. There’s a lot of information about that [here](http://en.wikipedia.org/wiki/Transmission_line). ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [November 29, 2012, 7:19pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/32 "2012-11-29T19:19:53Z")
Not two wires - it’s between one wire and the surrounding seawater/grounding. As current flows, it induces magnetic fields which induce current in turn - thus as mentioned above, applying an instantaneous rise in voltage at one end does not create an instantaneous rise at the other end. A square wave (instant on, instant off) is actually a sum of various harmonics of sine waves. As a resultof capacitance and inductance, the effect is as if each frequency of sine wave travels at a different speed. the signal is “smeared”. As mentioned in the Wired article, the intial bull-headed engineer solution was to turn up the voltage. That did not change the fundamental physics. ---
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [November 29, 2012, 9:56pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/33 "2012-11-29T21:56:10Z")
But does an electrical signal actually travel along a conductor at the speed of light? I remember reading that, while individual electrons move at the speed of light, they moved in all sorts of directions, but the sum of their movement was along the conductor. The actual speed of the signal along the conductor was thus determined more by factors like voltage, resistance and the conductors characteristics than the local speed of light. Not even fiberoptic cables carry signals at the speed of light (the actual light beam bounces from side to side along the cable, travelling a distance far greater than the actual length of the cable). ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [November 29, 2012, 10:03pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/34 "2012-11-29T22:03:32Z")
> [@dstarfire](#): > > But does an electrical signal actually travel along a conductor at the speed of light? > > I remember reading that, while individual electrons move at the speed of light, they moved in all sorts of directions, but the sum of their movement was along the conductor. The actual speed of the signal along the conductor was thus determined more by factors like voltage, resistance and the conductors characteristics than the local speed of light. > > Not even fiberoptic cables carry signals at the speed of light (the actual light beam bounces from side to side along the cable, travelling a distance far greater than the actual length of the cable). No, as stated above, signals in coaxial cables move at much less than the speed of light, usually 70-90% of c. Also, the individual electrons move very, very slowly. It’s the Electrical Field that travels quickly. ---
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [November 29, 2012, 10:26pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/35 "2012-11-29T22:26:34Z")
> [@beowulff](#): > > Also, the individual electrons move very, very slowly. It’s the Electrical Field that travels quickly. That means the electrons move as a result of the electrical field, rather than generating it by their movement, correct? or are there some weird physics going on that allow the field to move faster than the objects affecting it? They’re both equally mind-bending. ---
**Author:** ![lisiate](https://avatars.discourse-cdn.com/v4/letter/l/f05b48/32.png) [@lisiate](https://boards.straightdope.com/u/lisiate)\ **Post date:** [November 29, 2012, 10:31pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/36 "2012-11-29T22:31:45Z")
> [@Keeve](#): > > 19 mps is about 3 minutes for a one-way trip. If they verified each character, that’s 6 minutes. Add in a good number of retries, let’s say and average 10 minutes per character? That’s 6 characters per hour. > > The OP says that the message was 98 WORDS. At 5 letters per word, without blanks, that’s 490 characters. Over 17 hours, that’s 29 characters per hour. > > Yeah, the math sounds right to me. Or even impressively fast. You’ve slightly underestimated the length of Victorian words. Here’s the full text of the first cable (from[here](http://www.itelegram.com/telegram/Atlantic_Cable_150.asp)): [QUOTE=Queen Victoria] “The Queen desires to congratulate the President upon the successful completion of this great international work, in which the Queen has taken the deepest interest. The Queen is convinced that the President will join with her in fervently hoping that the electric cable, which now connects Great Britain with the United States, will prove an additional link between the two places whose friendship is founded upon their common interests and reciprocal esteem. The Queen has much pleasure in thus directly communicating with the President, and in renewing to him her best wishes for the prosperity of the United States.” [/QUOTE] I count (well Word did it for me) 521 characters without spaces, 619 with. Giving a transmission rate of 36 characters per hour (including spaces). ---
**Author:** ![wheresmymind](https://avatars.discourse-cdn.com/v4/letter/w/91b2a8/32.png) [@wheresmymind](https://boards.straightdope.com/u/wheresmymind)\ **Post date:** [November 29, 2012, 10:51pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/37 "2012-11-29T22:51:57Z")
Wow. It must have been quite amazing at the time to be able to communicate with someone across the ocean in a single day. But I didn’t realize just how slow the first cable was (although I’m not really surprised now that I think about it). The ping time may have been much faster, but the bandwidth would have been orders of magnitude lower than just transporting a bunch of letters by ship! ---
**Author:** ![lisiate](https://avatars.discourse-cdn.com/v4/letter/l/f05b48/32.png) [@lisiate](https://boards.straightdope.com/u/lisiate)\ **Post date:** [November 29, 2012, 10:58pm UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/38 "2012-11-29T22:58:45Z")
The then holder of the [Blue Riband](http://en.wikipedia.org/wiki/Blue_Riband) the [_Persia_](http://en.wikipedia.org/wiki/RMS_Persia) made the crossing in 9 days, 16 hours and 6 minutes (232 hours). She had a gross registered tonnage of 3,300 tonnes, so could carry maybe 1,000 tonnes of cargo? In 232 hours the cable could have transmitted 8,352 characters - one decent sized Victorian epistle or so. So for bulk data transfer the ship smoked the cable. Still have things really changed that much. How much data can you fit onto a 747 laden with USB drives? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [November 30, 2012, 12:04am UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/39 "2012-11-30T00:04:14Z")
> [@lisiate](#): > > The then holder of the [Blue Riband](http://en.wikipedia.org/wiki/Blue_Riband) the [_Persia_](http://en.wikipedia.org/wiki/RMS_Persia) made the crossing in 9 days, 16 hours and 6 minutes (232 hours). She had a gross registered tonnage of 3,300 tonnes, so could carry maybe 1,000 tonnes of cargo? > > In 232 hours the cable could have transmitted 8,352 characters - one decent sized Victorian epistle or so. So for bulk data transfer the ship smoked the cable. > > Still have things really changed that much. How much data can you fit onto a 747 laden with USB drives? Just for fun: [747-ERF](http://en.wikipedia.org/wiki/747-400#Specifications) can carry 248,000 pounds of cargo. Looks like hard drives are up to 4 terabytes each now, and a 3.5" SATA drive weighs in at about 1.6 pounds. So that’s 155,000 hard drives, for 620,000 petabytes of data. Flight time from Dulles to Heathrow is 7hrs 15min. So bandwidth is… 23.8 terabytes per second. In the 9+ days it would have taken the Persia to make the crossing, the 747 could have made 15 round trips, moving 1860 tons of cargo in each direction. Double the time (so the Persia can make a round trip and move 1000 tons of cargo in each direction), and the 747 wins by a factor of 3+. ---
**Author:** ![lisiate](https://avatars.discourse-cdn.com/v4/letter/l/f05b48/32.png) [@lisiate](https://boards.straightdope.com/u/lisiate)\ **Post date:** [November 30, 2012, 2:12am UTC](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200/40 "2012-11-30T02:12:01Z")
Awesome, 23.8 terabytes per second is a lot faster than any current transatlantic links we have now isn’t it? [Previous page](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200.md?page=1) [Next page](https://boards.straightdope.com/t/why-did-the-first-transatlantic-telegraph-messages-take-so-long-to-transmit/497200.md?page=3)