The History of Subsea Cables

So today we're going to start to talk about them, because, as it turns out, there's a lot to cover with undersea cables to kind of understand not just how they work, but the challenges that people faced in order to make them a reality in the first place. This is also a timely topic because recently a company called x Links made headlines for the Morocco UK power plant project. That project's goal is to create a bowler and wind farm in Morocco and use a very very long sub sea

power chord, essentially to send electricity to the UK. Now, while a lot of headlines called this the longest subseed cable, that's misleading because there are actually many different types of cables, and technically the ce ME WE three cable that's s E A dash M E dash W E three, the number three cable is actually about ten times longer than what the Morocco UK cable will be. But we're gonna get to all that probably in the next episode, definitely

not this one. But as and Tricks pointed out in a tweet to me, undersea cables trace their history back to the mid nineteenth century. So in order to understand all of this, we really have to take a moment and talk about the telegraph and the development of the first undersea cables. So there were a few things that had to happen for undersea cables to even become a necessity. You know. One of those was the development of the electric telegraph, because without that, there's no need to worry

about subsea cables. Right, If you don't have long distance electric based communication, then cables aren't really a thing you gotta worry about, at least as far as connecting, say an island to a continent. Now, the word telegraph is Greek and it means essentially distant writing. But this word actually predates electric telegraphs. For example, there were semaphore systems,

ones that used visual cues with flags. Those were used throughout France, and we're really developed during the Napoleonic wars, and that was referred to as telegraph. Before any kind of electric version came along in the late seventeen hundreds, you had various smarty pants around the world experimenting with electricity, you know, like Ben Franklin, and this was just something that was just beginning to be understood at the time.

Alissandre of Volta had created a sort of proto battery that we later called a voltaic pile or and then later on we had the voltaic cells. These inventions could produce a good electric current, but at a very low voltage. Now we need a reminder here because we're gonna be talking about electricity a lot. Voltage in electricity is sort of similar to water pressure in a plumbing system. You can think of it as how much oomph a current has, and current you can think of as the amount of

electricity present in a system of flowing electricity or flowing electrons. So, if we want a really quick analogy, if you had a low voltage, high current source of electricity, that's kind of like a lazy river, right. The river can be really wide and it might be really deep, so you've got a lot of water there, but that water isn't moving very quickly. It's just lazily going down. A high voltage, low current electric device produces a very tight, high pressured stream.

So think of like a a concentrated stream of water coming out of a pressure hose. You don't it's not nearly the same amount of water as the lazy river. It's much less current in other words, but the pressure or voltage is way higher. Well before Volta's discovery, scientists and engineers were mostly reliant on devices that would build up electrostatic charges. So electro static charges have a high voltage but a low current, and they have limited applicability

in things where you need sustained electric current. So Volta's invention would allow for new applications of electricity. Now in the early eighteen hundreds you had some other smarty pants like Hans Christian Orstead of Denmark. And by the way, as always, my apologies for all the mispronunciation, and I'm going to do of all the different names that is on me and I apologize. However, he discovered that electricity

and magnetism have a connection. He observed that a magnetic needle would deflect from magnetic north if it came close to a wire that was carrying an electric current or transmitting an electric current, and so we first began to realize that electro magnetism is a thing, that there is this relationship between electricity and magnetism. This would lead to yet more smarty pants people thinking of ways that we could use electricity through wires to communicate across vast distances.

One way, a way that Sir William Father gil Cook and Sir Charles Wheatston suggested was to have a multi wire system that would use up to five needles. They experiment with different ones, but the one that they would use heavily would have five needle pointers, and that would

be at the receiving end of this system. So you could send different electrical signals down these different wires and thus direct these needles these pointers to point to different letters on a placard that would have the alphabet there. Uh The system would remain in use in the UK up through the early twentieth century, so the UK was reliant on this system, whereas the rest of the world

would move on to other ones. The neat thing about the system is that it arranged the alphabet in a diamond pattern, so it only used twenty letters of the alphabet. It left out the letters C, J, Q, U, X, and z, so sometimes you had to do, you know, approximations of certain words. And the letter A was at the top point of the diamond, and then you know, you had B and D at the next level, and then so on and so forth, and then at the bottom you had the letter Y. And the five needles

were split right in the middle of this diamond. They were in the widest part of the diamond, pointing up and down normally, which meant that they weren't pointing at any specific letter. So by sending signals down specific wires, you could make needles point to a specific letter. You would have both of you know, two needles that were on a diagonal line with a specific letter, and by looking at the common letter that both needles were pointing at,

you could spell out words. An interesting approach, not necessarily the fastest, but it worked. Later on, Wheatstone would create a different system that had a circular dial uh than a needle on the inside, and you had the alphabet laid out along the inside circumference of the circle, so sort of like an analog clock, except instead of numbers for the time, you had the alphabet, and you also

could have numbers as well. Then you had keys that matched the letters and numbers that were along the outside of the style. So pressing down on a key would indicate, Okay, I want to send this letter UM, and this is the sending station, And then you would have a receiving station on the other end that would have a similar dial with a needle and the letters and numbers in it, and pressing down a specific key would end up sending a signal that would have the needle on the other

side point to the relevant letter or number. This way was really neat and the way it worked is super cool. But I'm gonna have to save that for another episode because I'm supposed to focus on subsei cables, and I wrote about a page and a half of stuff before I realized I am getting way off track, so I'll spare you for now, but that will come up maybe

in a future episode. Now, in America, it was Samuel Morse, who interestingly was an art professor who came up with the famous method for transmitting messages electrically using a special code, one that today, of course, we refer to as the Samuel Code. Don't wait no, I'm sorry. No. Morse code.

Morse code. Morse code uses dots and dashes to rep letters and numbers, and by tapping the dots and dashes on a telegraph key, you could send pulses of electrical signal down a wire, and a receiver at the other end could then emboss dots and dashes on a strip of paper, so you could actually read out the dots and dashes and translate it that way, or later on you had engineers who are trained to listen for dots and dashes, and you had a device that was essentially

tapping like a little anvil, tapping out the messages, and you would just listen. Later, a guy named Alfred Vale would partner with Morse to refine this system and make it a little more practical, essentially looking at the most frequently used letters and using the the simplest dots and dash patterns to represent those letters, as well as to

redesign the telegraph key itself. By eighteen thirty seven, Veil and Morse were demonstrating this technology, and by eighteen forty three they secured funding to set up an experiment telegraph line that stretched the thirty five miles around sixty kilometers between Baltimore, Maryland and Washington, d c Here in America. The project used poles that were erected alongside a railroad line and wires connected to the poles via glass insulators,

and it worked. One thing that really amazed me as I was doing research into this, just as a quick digression, is how quickly things moved. Because this was eight three, and we're gonna be talking about a transatlantic subsea cable by the end of this episode. That came a little more than a decade after that. And to think of it being ten years, a little more than ten years between stringing sixty kilometers of cable between two cities in America to laying a subsea cable across the Atlantic Ocean

blows my mind. Well, anyway, the demonstration was a success, and it didn't take long for railroad companies to start building out tell alegraph systems, and early on they were almost exclusively used to help keep track of traffic on the rail system, to better plan out routes, and to

avoid long delays or accidents. By the end of the eighteen forties, journalists were starting to make use of the telegraph system to wire stories across vast distances, and businesses began to get interested in this as well, the ability to be able to conduct business between cities without having to take you know, a train ride or otherwise have you know, like like people on horseback travel from one city to another. Because keep in mind this is this

is before the automobile has really become a thing. So yeah, there were limited ways of getting information from one point to another. However, until eighteen fifty, these distances were all

over land. The reach of telegraph systems ended at the coastlines, which meant that while regions could develop a sophisticated internal communications system you know, inside their border or maybe between borders of neighboring nations that shared you know, a land border, once you hit the ocean, you had to rely on other methods, much slower methods. So a mail ship isn't a ship that carries mail, not a not a gendered ship, but a mail ship between London and New York could

take nearly a month to travel across the ocean. A fast one might be able to make the journey in three weeks. By the mid nineteenth century, steamships were largely taking the place of sailing vessels. They could make the journey in up around ten days, so still more than a week to get from one point to another. That's pretty slow for news to travel. It was difficult to act with alacrity if you were relying upon information from

across the pond. So there was a strong use case to make for creating an undersea cable infrastructure that could connect distant parts of the world, you know, parts that were separated by oceans, and even in Europe, like England in particular, saw the need to do this because while the distance was not nearly as great to travel from say Dover to France, the delay in getting information from other parts of Europe was still pretty considerable, so there

was definitely a need for that as well. This did, however, present some engineering challenges because you had to find a way to make this both practical and affordable. Now this is going to be obvious, but I need to establish it. It is way easier to repair and maintain infrastructure that's above the water than it is to do below the water. And that's because we live above the water and we can't live below the water, at least not with the same amount of freedom. And since the Mr folks seemed

completely uninterested in helping us maintain communication channels. We have to take that into consideration. To that end, we have to treat cables subseed cables different from terrestrial cables. We have to take into consideration what being submersed in ocean water is going to do to a cable over time. We have to understand that those effects can be detrimental.

We have to be able to estimate how long a particular cable is likely to remain viable, assuming no catastrophic instances occur, like assuming that a ship's anchor doesn't tear through the cable, for example. So we have to make sure that we have the budget to not just install a cable in the first place, but to potentially replace that cable when we near the end of its estimated lifespan. It has to make financial sense, or else it's a

loss in the long run. Right. So you can argue, yes, it's invaluable to have two distant places connected together, but if you're constantly having to replace the communication channel, then that invaluable might start to take on of value where you just say, yeah, it's invaluable, but I don't want to pay for it. So coming up with a way to make subsea cables work extends beyond just the technology. I mean, obviously the tech is a critical component or

else nothing happens. But you can't ignore the financial element, right or the physical challenges, because if you do that, you're setting yourself out to fail. So we're gonna take a quick break. But when we come back, we're gonna talk about a couple of other things before we get to the first subseed cable, like some basic things about electrical transmission. But before we do that, let's take this

quick break. All right, So in the eighteen twenties and eighteen thirties you had all these various smarty pants is is all learning about electro magnetism. And we now know that if you pass an electric current through a conductive material, that generates a magnetic field. And similarly, should you have a conductive material like a wire, encounter a magnetic field, that field will induce an electric current to flow through

the conductive wire. And you've probably played with this in school, making a simple electro magnet with like an iron nail, some copper wire, and a battery. You know, you connect the wire to either terminal of the battery, you've coiled the wire around the nail to act as a core, and it becomes magnetic. You can pick up paper clips and stuff. I remember I did that in school. I imagined that people still do well. There's a whole lot more to electro magnets, but we're just going to focus

on a couple of little things first. And the first important bit is, because of this relationship between electricity and magnetism, we need to make sure that wires and cables that we use to transmit electricity have really good insulation around them. And that's because us Without insulation, that is, without some sort of barrier that resists the flow of electricity and the interaction of magnetic fields, you have the potential for interference.

So let's say you've got two copper cables and there's no shielding on them, you don't have any insulation on them, and you've got them close to each other. And then let's say you send electricity through one of those two cables,

not the second one, just cable number one. Well, as the electricity flows through cable number one, that creates a magnetic field which overlaps to the second cable, and that induces a current to flow Now, if we're using direct current something like a battery, uh, the second cable will only have electric current running at the very beginning when

that magnetic field first hits it, but then it will stop. However, if the source is alternating current then which means that the current is changing direction many times per second, then what you have is a fluctuating magnet at it field. Because the magnetic fields direction also changes many times per second, that will continue to induce electricity to flow in the second cable. This would be in interference. It creates phantom signals when no signal is intended, or it interferes as

one signal overpowers or changes another. I remember back in the day, I had these cheap desktop speakers that I had connected to my computer, and I would put my cell phone down on the desk, and every time my cell phone got a notification, it would make this weird electric chirping noise in the speakers because that was radio frequency interference that was inducing a current to flow through the speakers. So these are things that can happen, and

you don't want them to write. You want to shield your components so that only the signals you want to send are going through so you have to protect a against that. Now, in the nineteenth century, there were people who discovered a plant that had a kind of sap essentially that was found to be a really effective insulator, so it resisted the flow electricity and protects or insulates against interference. That material is called Gutta percha. It's a

biologically derived latex. And like I said, the plant has the name Gutta percha, but that's also the name everyone used for the derived latex from it. Now, this was fortunate at the time, but I should also add that the telecommunications industry would spell doom for the Gutta purchase trees because the rampant harvesting of the trees created an

unsustainable situation. And before too long people realize, oh, we need an alternative to this, because pretty soon there's not going to be any of this plant left on the planet will have harvested at all. Anyway, Gutta percha has many of the same properties as synthetic rubber, including the ability to insulate conductive materials. Next, we need to think about what happens with electricity as it travels over greater

distances of wire um. This is going to get more complicated later in this episode, because, as it turns out, there are certain things that we have to take into consideration with any length of cable, and then there are other things that come into play when you're talking about cable that happens to be under the water. But under most circumstances, even a great electrical conductor has some level

of resistance. Now I say under most circumstances, because as it turns out, if you're able to super cool a conductor, like a good conductor, and you're able to get it down to an incredibly low temperature, like just a few units of kelvin above absolute zero, then you can have a superconductor which has no resistance. But under most normal conditions, you know, conductors have resistance to electricity. You can think of electrical resistance as kind of being like friction. It's

working against or resisting the flow of electricity. So resistance depends upon a few different factors, such as the material itself, like some conductors are better than others, like coppers a really good conductor, and it also depends upon the thickness of that material. A thin copper wire has a greater electrical resistance than a thick copper cable for example. Well, resistance means that as you transmit electricity across this conductor,

you'll see the electrical energy diminish over distance. And we know that energy can be neither created nor destroyed, right, so we're not destroying that energy. However, that energy is converting from one type to another. In this case, the resistance causes the conductive material to heat up and we lose some of that electrical energy in the form of waste heat. So if you want to push electricity further down a trans mission line, you really have to use

a lot of voltage. And remember voltage is the pressure in this system. So with alternating current, we can actually use devices called transformers, which, while they are not robots, they are arguably more than meets the eye. If you were to look at an electrical transformer, like open up a cover, and by the way, never do that, but if you did do that, you would see that consists of two coils of conductive wire wrapped around a core, usually a ferro magnetic iron core in a simple transformer,

not necessarily a solid core, but a core. So passing electricity through one coil of this wire induces electricity to flow through the other. We already talked about inductance, right, and the number of turns in each coil determines a change in voltage. So let's say we've got coil number one, which will call the primary coil. This is the coil where we're going to send electricity through the wire. Let say that primary coil has five turns and coil number two,

which is our secondary coil, has ten turns. Well, then the ratio of turns is one to two, one for primary, two for secondary, and the voltage of the second coil will be double that of the first coil. This is a step up transformer. We're stepping up the voltage. We're increasing it by a factor of two. Now, if the primary coil has ten turns and the secondary coil has five turns, that's a two to one ratio. That means the voltage of the second coil will be half that

of our first coil. This is a step down transformers. So using this we can then push voltage up on terrestrial power lines that are using alternating current. Again, this only works with alternating current, not direct current. Then you can increase the voltage for long distance transmission. You can overcome the problem of loss due to resistance. Essentially, you've just you turned the pressure on so much that it's it's powering through that. Now you have to have the

right kind of cables to make that happen. You have to have the transformers along the way, and you have to step down the voltage before you feed that current into say a business or a house. But it's entirely possible to send electricity long distances overground using transformers. Anyway, it's one thing to have a transformer above the waves. If you've ever been around when a transformer blows out, you know that this is a spectacular and often terrifying event.

There's a very loud boom, and it's like a thunderclap or a shotgun going off, and then there's a shower of sparks, and then all the power goes out and it happens like in that order instantaneously. It seems now that is inconvenient here upon the surface world, but below the waves that would be much worse. So we have to keep that in mind when we're talking about subsea cables. Some of the solutions that we have to us here on the surface would not be available to us underwater.

Now Samuel Morse himself tested the viability of an underwater telegraph cable. He used a wire coated in tar and India rubber to insulate the wire from the water because he didn't want to lose electricity through the water. Essentially, he submerged the wire in the New York Harbor and he sent a telegraph signal through it, and the experiment was a success. This signal came out the other side. It worked. So as early as eighteen forty two, engineers

understood that an undersea cable was possible. The question was could be made practical. The first underwater cable using Gutta Percha as an insulator, was laid between Deut's and Cologne across the River Rhine in eighteen forty seven, and then in eighteen forty nine and Electrician with the Southeastern Railway succeeded in laying two miles of cable off the coast of England around the Kent region. But the first commercial

subseed cable would follow the year after that. It was eighteen fifty and two brothers, Jacob Brett and John Watkins Brett created the English Channel Submarine Telegraph Company. Now the brothers had proposed laying a cable under the sea through the English Channel and connecting the port towns of Dover, England and Calais, France. Both England and France agreed to this proposal, so the brothers got the funding they needed to to try and make it happen, and they had

a deadline that they had to meet. So the brothers purchased cable from a company called the Gutta Purchase Company. The cable had Gutta Purchase insulation on it, but it had no armoring to protect it from other hazards. So it's a copper cable with a rubber like insulating layer on the outside and that's it. Uh. It was just a single copper wire too, it was not We're not multiple cables or wires in this. So in many ways this would be an experiment and ultimately it would be

only partially successful. Uh. In that really it was a failure, but it taught them a lot of lessons. So the cable the brothers used was too light to sink on its own. It would not sink down to the sea floor. So every one hundred yards or so, workers on board the ship that would unspool the coil of cable, had to attach lead weights to the cable. The weights ranged between ten to thirty pounds, and the company used a steam paddle ship called the Goliath to carry the cable

across the channel. They attached one end of the cable to the dover shore side of the connection that went up to a telegraph station, and then they began the journey to France, and the ship would have to stop every one yards or so in order to sink another weight down with the cable to keep it in place on the ocean floor, and had to stop each time. So it's not like, you know, they were just leading this out and staying in motion the whole time. They

stopped every hundred yards. It took the whole day for the ship to lay the cable across to reach France, and there the team attached the cable on the French side they attempted to establish an electrical connection. I'm not entirely sure the outcome of that attempt, Like the accounts I read don't seem to really indicate whether or not they were successful in getting an electrical signal all the

way across. At any rate, if they did, it was a week one and by the next morning, the connection had been severed and the line was just totally dead. Not long after that, stories began to circulate that some French fisherman had accidentally dredged up the cable in some netting and then subsequently severed the cable. However, that story was never verified. It didn't stop people from spreading variations of that story, including variations that made the fisherman look

increasingly dimwitted over time. But the stories that were published immediately following the failure actually suggested that it was the action of the waves off the rocky coast of France that was making the cable rub against rocks and then and then break that way. What was certain is that the cable did break, whether it was a human caused error or because of the action of the waves, and that's probably because there was no armoring on the cable.

So there you go. The brothers sent a letter to the Times in England explaining that while their first attempt failed, they had learned a great deal in the process, and they explained that the thing that they had attempted had never been done before, and as such they were going in ignorant of what would and wouldn't work. But through this experience they had learned some valuable lessons and were more convinced than ever that a cable connecting England to

the European continent would work. Whether they wrote that letter in an effort to, you know, make sure they still had funding for future attempts, or this was a genuine expression of their enthusiasm, I don't know. Maybe it was a mixture of both, or maybe it was something else entirely. But the important thing is they were right. When we come back, I'll explain and tell the rest of their story,

all right. So the Brett brothers still had some time left before their agreements with France and England would expire, specifically with the French government, and if that happened, they were going to have to go through the whole process of securing permission all over again. That was not a guarantee, especially you know, after having failed their first try. So they were determined to make another go at it before time was up, and this time they would add more

protections for the cable. That cable would contain not one, but four copper wires, each insulated by Gutta percha. In fact, h wire had a double layer of Gutta purchase installation, so that you had a wire that was the core, and then you had a rubber case essentially on the outside of that, and then a second rubber case on the outside of that. The engineers then bound those four wires together with yarn soaked in tar and tallow, so

together the yarn tar tallow mixture. There's some other stuff in there as well, and the four wires encased in Gutta percha served as the core of the cable itself, and that soaked yarn provided some more stability and strength. The bound cables now formed a kind of rope, and the next step was to weave ten strands of galvanized iron wires around the rope to provide armor protection. Galvanization is a process through which you apply a protective coating

of zinc into onto something like iron or steel. Typically, the way it works is you make whatever thing you're making out of iron or steel, and then you immerse that in molten zinc, which then adheres to the exterior of the metal. That helps prevent rusting, which has an important consideration if you've got a cable that's going to be submerged in salt water. Throughout its lifespan. You know,

saltwater will cause stuff to rust pretty darn quickly. So the iron wires were protected with this zinc coating and the they were they measured about five six of an inch in diameter, and like I said, there were ten of them that would be woven together to create the armored sheath for this cable. Now, according to a piece in the Illustrated London News, the brothers employed an engineer named George Fenwick, who invented and built a machine in just ten days to weave these iron wires around the

cable of you know, copper wire and yarn. And it had to be fast, and it had to be delicate. It could not damage the copper itself. If the copper broke inside the rope, then you could have a broken connection. I would love to describe this machine to you, but I've only seen a few descriptions without visual aids. I think I would really do a poor job of explaining it. But let's talk about what the machine had to do.

It had to draw this rope, this this cable of yarn and copper wires through a machine and had to weave around that rope the iron wires in a pattern that was tight enough to provide armor protection for the copper inside, and it had to do it without breaking the copper. The machine was able to draw off eleven inches of cable in a single revolution of its steam engine, and it had a revolutions per minute speed of eighteen, so it would revolve eighteen times and eleven inches of

cable would go through each revolution. That means that if I'm doing my math correctly, it could weave the iron armoring for sixteen and a half feet of cable every minute, which is pretty impressive now, granted they're making miles and

miles of cable. In fact, overall the primary cable was twenty four miles long, and it took about three weeks to make the whole thing, And the plan was to use those twenty four miles of cable to span the twenty one miles of distance between Dover and Clay, the thought being that the three extra miles would be plenty to deal for the fact that you're sinking it under

the water. As it turns out, the cable wasn't quite long enough to reach, so in the end they actually had to splice an additional mile of cable onto the French side of this in order to make a connection work. But fortunately that would work out. Now, the twenty four miles of cable, the primary cable weighed around a hundred eighty tons and when it was coiled up, it made a coil that measured fifteen feet in diameter on the inside of the coil thirty feet in diameter on the

outside of the coil. Once constructed, cruise loaded the cable onto a steamship called the Blazer. Now the ship was pretty much gutted before the cruise loaded the cable onto it. They pretty much stripped it of everything and essentially it became a barge that would be pulled by tug boats, a pair of them. Now this was in Wapping, an area in London on the Thames River, so the tug boats would tow the Blazer out the Thames, down to the sea and around the coast of England to Dover. Now,

the laying of the cable would not go smoothly. For one thing. While the iron weaving machine was a work of genius, and while it was able to work pretty quickly, it was not always flawless. Um there were some breaks in the iron wires along the length of the cable, so you had little bits where, you know, a strand of iron would be broken a little bit and it would start to stick out. This created surfaces upon which

something could snag you weren't careful. This would become important as the crew laid the cable between Dover and Calais, and the first problem popped up right away. So the coil still aboard the blazer, which again was being towed by some tug steamers, snagged as it was uncoiling and they were laying the cable into the sea. So the tug boats had started moving a little too quickly. They got up to a top speed that was like five knots, which isn't super fast, but it was too fast to

uncoil the cable safely. And one of those broken iron wires snagged on a surface as the the cable was being uncoiled and put into the ocean, and an eighteen yard length of that cable was stripped of that one strand of iron wire, not the whole iron casing, but

one of the ten strands of wires stripped away. Now the armor consisted of ten iron wire, so this was not you know, a true disaster, but it did send the message that they needed to go a little more slowly, which was tough because the weather was also really bad, so spending more time out in bad weather on the sea not a high priority. But the captains of the tug boats were told don't hit the steam quite so hard.

Then the weather started getting rough and the tiny ship was tossed, so to speak, And as the ships got closer to France, the seas were very heavy and a strong wind was blowing, and at one point the tow rope connecting the Blazer to the tug ships snapped and the Blazer was set adrift, and it took some time to reconnect the Blazer to the tug ships, during which the Blazer had drifted about a mile and a half

off course. The delay meant that it was near nightfall when they were finally approaching France, and the storms in the darkness meant conditions were just too dangerous to complete the connection, so the Blazer anchored for the night. The next day, the weather was not much better, and the tug ships pulled the Blazer to within a mile of the shore of France, but they couldn't really get any

closer because of the weather. So the crew decided to attach the end of the cable to a buoy, and this freed up the Blazer and the tug ships towed it back to England. Now the captain of another ship called the Fearless took over his ship, took up the end of the cable that was secured to the buoy, and then brought a little bit further, like another hundred

yards or so, and then moored the cable. And the next day representatives from the Gutta Perch Company UH they joined the Fearless and they brought along with them an additional mile length of cable. So then the crew spliced

the two cables together and formed a new one. And then they brought the fresh length of cable onto shore of France after much delay, and a French crew then laid the cable up to the French connection uh not the movie, but the actual connecting terminal point for the French side of the telegraph system, and the crew also

buried some of the cable to keep it protected. Upon testing the cable, the teams were pleased to find out that they had established a working signal line between Dover and Calais and they actually did a heck of a demonstration to prove that it was working. It's one of my favorite stories about testing the technology. Okay, so here's what they did. At Calais. There are fortifications, it's a port town on France, and that's across the English Channel

from England. England and France had had sometimes a contentious relationship in history. So there were ramparts along parts of

Calais and on them was a cannon. So engineers connected the cannon to this electrical signal line connected back to England, and a current with sufficient voltage would ignite the cannon sign system, which would then cause the cannon to fire and so many miles away across the English Channel, an engineer sent a pulse of electricity from Dover, England to go through the subsequent cable, and that provided the juice

necessary to make a cannon in France fire. Obviously, this was not the first time that the English made the French fire a cannon, but at least this time there were no hostilities involved. Now, the telegraph in this case used the pointing needle mechanism that I referred to earlier, rather than Samuel Morris's version that makes sense. Morse code when it was first introduced, only had codes for the

letters that we typically encounter here in America. So in America it's pretty unusual to run into characters that have an accent on them, like an accent ague, for example, or letters that have an oomb out or anything like that. Over in Europe it's more commons, so they needed to have a method that would allow for that. Now, despite all the bumps along the way, the cable seemed to

work exactly as was intended. The insulation around the copper wires remained secure even after some of that iron armor had been stripped off. The cable and the Submarine Telegraph Company that the name had simplified over the years received some criticism for putting the entire endeavor at risk because they did this operation during unfavorable weather. Essentially, some people were saying, you're really lucky that this works, because you're an idiot for having to lay down subseed cable when

the cs are so rough. However, in defense of the company, they didn't really have a choice in the matter because they were rapidly approaching the deadline that France had set, and if they did not get the cable laid in time, then the whole project was going to be a failure and all the money was going to go away. So really this all happened in the nick of time, and those risks were necessary once if they wanted to actually,

you know, make this work now. To send signals through cables of great length, companies need to supply, like I said, a good deal of voltage to overcome resistance. But there were other issues that placed fundamental limits on how far or how fast you could transmit electricity and thus information across simple copper wire. So we're going to talk a little bit about that before I wrap up, and then in the next episode we'll talk more about the Transatlantic

telegraph cables. So I've mentioned resistance and voltage and current, but things get significantly more complicated when we start talking about transmitting a signal across very long cables that are underwater or underground. Now, technically these things happen in shorter cables too, but if the distance is short enough, you might not even notice that there's a problem, or it may not be bad enough for it to be an issue.

But we definitely see them over great distances with cables that are submerged or buried Michael Faraday, whom I've talked about frequently on this podcast a true Genius U He had a hypothesis about undersea cables or buried cables, and this was based off the observation that another smarty pants named Sir Francis Ronalds had observed way back in three He saw that if you had two insulated wires of equal length and gauge, and you buried one of them,

and you tried to pass electrical signals through each of them, the above ground one would work just as you would expect, but the one that was buried would have trouble carrying the signal. The signals seemed to be moving more slowly, as if something were putting the brakes along the way. Faraday concluded that this was because of induction between the wire and the earth surrounding the wire, or, in the case of submerged sea cables, the water. So what does

that actually mean. Well, essentially, the cable and the water behave kind of like a laden jar or liden jar. If you pass an electric current through the cable, it induces an electric charge and opposite electric charge in the water, and opposite charges attract one another. This attraction is kind of like putting the brakes down on a signal. It doesn't stop it, but it slows it down. They called

it retardation of a signal. Faraday described the flow of electricity along and underwater cable as behaving like a wave, which honestly was really ingenious. He said that the result is you would first get a weak signal from the receiving end, and that signal would slowly grow in strength. Then the strength would start to fade away again, and this would happen in cycles again, very much like waves

crashing on the beach. Then we've got William Thompson, who would later be known as Lord Kelvin, and they're super important scientist. Not only would he propose the system of absolute temperature, and we would later describe this in units called kelvin zero, kelvin being absolute zero, he was also

instrumental in telegraphic engineering. Thompson built on Faraday's work, realizing that the diameter of the conductor was fundamentally important when determining the speed at which a signal will travel through a cable, and he also came up with an equation to describe how signals passed through cable, and it goes

like this. The speed of a signal passing through a wire decreases as the square of the cable length increases, So signaling speed has an adversely proportional relationship to cable length, assuming that you're sticking with the same cable gauge. Gauge in this case relates to a cable's capacity and resistance. The larger the diameter of the cable, the lower the

resistance will be. And we're going to stop here, but that issue that Lord Kelvin found would become um one of the big challenges to overcome when looking at laying very long subseed cable. So in our next episode we'll talk more about the quest to lay a cable along the Atlantic Ocean so that we could connect Europe to North America, and about the engineering issues that we needed to figure out, and then about how Lord Kelvin came up with even more important ideas about how to deal

with this so that it could become practical. But we'll cover all that in our next episode. If you have suggestions for future episodes, be like and tricks send me a message on Twitter. The handle we use is text stuff hsw and I'll talk to you again really soon. Text Stuff is an I heart Radio production. For more podcasts from my heart Radio, visit the i heart Radio app, Apple Podcasts, or wherever you listen to your favorite chips