The Transatlantic Telegraph Cable
Four Failed Attempts and the 1866 Cable That Worked
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Chapter by chapter, it details how Whitehouse's high-voltage error destroyed the first cable, how Lord Kelvin's mirror galvanometer helped locate breaks, and how the ship Great Eastern finally laid a working cable in 1866. The book explains how communication speeds improved dramatically, from hours to mere minutes, changing news reporting and financial markets forever.
This account of transatlantic telegraph technology will appeal to anyone interested in engineering breakthroughs that changed global communication, from Victorian-era inventors to modern telecommunications professionals.
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In the 1840s and 1850s, people like Edward Thornton and Alonzo Jackman suggested building a telegraph cable across the Atlantic Ocean. These early proposals came before the successful attempts that would follow, laying the groundwork for what would eventually become a groundbreaking communication link between continents.
In 1840, Samuel F. B. Morse declared his confidence in the possibility of a submarine telegraph line spanning the Atlantic Ocean. By 1850, a cable had already been completed linking England and France. That same year, Bishop John T. Mullock, who was in charge of the Catholic Church in Newfoundland, put forward a plan to extend communication by laying a telegraph route from St. John's all the way to Cape Ray. He also suggested connecting this path with cables crossing the Gulf of St. Lawrence toward Nova Scotia, passing through the Cabot Strait.
While others were considering the idea, Frederic Newton Gisborne, a telegraph engineer in Nova Scotia, had a similar plan. In the spring of 1851, he secured a grant from the Newfoundland legislature. After forming a company, he began constructing a landline.
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In 1854, Cyrus West Field, a businessman and financier, met with Gisborne to discuss a project. After their conversation, Field began to consider the possibility of extending the cable that connected Newfoundland to the mainland all the way across the Atlantic Ocean.
Field, who knew little about submarine cables or deep-sea conditions, turned to Morse and Lieutenant Matthew Maury, a leading expert on oceanography. Maury studied soundings from many ship logs and mapped a route across the Atlantic that seemed promising. He named this stretch the Telegraph Plateau. His charts showed a direct path to the United States was too rough and much longer. Field then embraced Gisborne’s plan as a first step toward connecting America and Europe, promoting the New York, Newfoundland and London Telegraph Company to build the line.
The first major step in building the transatlantic cable was finishing the connection between St. John’s and Nova Scotia, a task given to Matthew Gisborne and Field’s brother. In 1855, an attempt was made to lay the line through the Cabot Strait, using a barque pulled by a steamer. But when half the cable had been laid, a storm struck, forcing workers to cut the line to save the ship. The following year, 1856, a steamboat was prepared for the job. This time, the stretch from Cape Ray, Newfoundland, to Aspy Bay, Nova Scotia, was successfully completed. The cost of this section surpassed one million dollars, and the transatlantic portion would prove even more expensive.
In 1855, Field crossed the Atlantic for the first of fifty-six times to meet John Watkins Brett, the top authority on submarine cables. Brett’s company had laid the first ocean cable in 1850 across the English Channel. Later, his English and Irish Magnetic Telegraph Company installed a cable to Ireland in 1853, which was the deepest one built so far. Field went to Britain because all the manufacturers of submarine cable were there, and he had not been able to gather enough funding for the project in New York.
Field moved fast, ordering 2,500 nautical miles of cable even before the company was formed. The Atlantic Telegraph Company came together in October 1856, with Brett as president and Field as vice president. Charles Tilston Bright became chief engineer, and Wildman Whitehouse, a doctor who taught himself electrical engineering, was named chief electrician. Field put up a quarter of the needed capital, and once the rest was sold mostly to investors in Brett’s earlier company, an unpaid board formed. William Thomson, later Lord Kelvin, joined as a scientist and advisor. Morse, a shareholder from the Nova Scotia project, also served on the board as electrical advisor.
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The first transatlantic cable was a complex structure, its core made of seven copper strands encased in four layers of gutta-percha, then wrapped in tarred hemp and protected by ten steel wires covered in impregnated hemp. Thomson studied how electricity traveled through this submerged wire, comparing it to a coaxial cable with an inner conductor and an outer one formed by the insulation and seawater. In 1854, he introduced concepts of electrical capacity and resistance per unit length, creating an equation that described voltage at any point in time and space along the line. His findings led to what became known as his law of squares and revealed the cable’s dispersive nature. Ten years later, in 1876, Heaviside added inductance per unit length to Thomson’s model, offering the key insight needed to solve the phase-distortion problem.
The cable was built with wires that weighed 26 kilograms per kilometer, or about 107 pounds per nautical mile, and each was covered in gutta-percha, a material suggested by Jonathan Nash Hearder. That insulation added another 64 kilograms per kilometer—roughly 261 pounds per nautical mile. Together, the cable weighed nearly 550 kilograms per kilometer, which is about 1.1 tons per nautical mile. Despite its weight, it was flexible enough to handle tension of several tens of kilonewtons, or several tons.
The Gutta Percha Company provided the cable, which was then armoured by wire-rope makers—standard practice of the time. Only four months were allowed for completion, so the work was split between two English firms: one from Greenwich and one from Birkenhead. Near the end of production, it became clear that the two batches had been twisted in opposite directions. That made direct wire-to-wire splicing impossible because the iron wire would unwind under tension during laying. They solved the problem by using an improvised wooden bracket to hold the wires together. The mistake created negative publicity for the project.
The British government backed Field with a yearly subsidy of £1,400, which is about £130,000 today, and provided ships for laying the cable and support. He also reached out to the U.S. government for help, submitting a bill in Congress that authorized a similar subsidy. The bill passed the Senate by just one vote, held back by protectionist senators. It cleared the House of Representatives despite strong opposition and was signed into law by President Franklin Pierce.
In 1857, the first transatlantic cable was laid using the converted warships HMS Agamemnon and USS Niagara, which had been borrowed from their governments. The cable began at the white strand near Ballycarbery Castle in County Kerry, Ireland, on August 5. It broke on the very first day but was repaired and continued. The line snapped again over the Telegraph Plateau, a section of ocean floor nearly 3,200 meters deep, leading to the abandonment of the operation for that year. Three hundred miles of cable were lost, yet the remaining 1,800 miles were sufficient to complete the task. During this time, Morse and Field had a conflict, and Morse was eventually removed from the board, ending his involvement in the project.
On 10 June, Agamemnon and Niagara set sail again, trying once more to lay the transatlantic cable. Ten days out, they met a severe storm that nearly ended the mission. The ships, loaded with cable and struggling to stay upright, suffered injuries to ten sailors and flooded the electrical cabin. They reached the middle of the Atlantic on June 25 and joined their cables together. Agamemnon headed east toward Valentia Island, while Niagara moved west toward Newfoundland. But the cable snapped three times — first after less than three nautical miles, then again after about fifty-four nautical miles, and finally when each ship had laid out around two hundred nautical miles. A new braking mechanism had been tested successfully in the Bay of Biscay earlier that May, but it wasn’t enough to prevent the repeated failures.
The expedition made its way back to Queenstown in County Cork, Ireland. Some of the directors wanted to give up and sell the cable, but Field convinced them to keep trying. The ships set out again on July 17, and by July 29, the middle splice was complete. This time the cable laid smoothly. Niagara reached Trinity Bay in Newfoundland on August 4, and the next morning the shore end was brought ashore. The Agamemnon arrived at Valentia Island on August 5, where the shore end was landed at Knightstown and connected to a nearby cable house.
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Messages were sent from Newfoundland beginning on 10 August 1858. The first of these reached Valentia on 12 August and was read there, then forwarded to Newfoundland by 13 August. Further transmissions followed over the next few days, with more testing and setup work done until 16 August, when the first official message was sent through the cable.
The Directors of the Atlantic Telegraph Company in Great Britain sent a message to their counterparts in America. The message declared that Europe and America were now united by telegraph. The announcement concluded with a religious phrase: “Glory to God in the highest; on earth peace, good will towards men.” This moment marked a historic breakthrough in global communication, connecting two continents through an undersea cable that had long been dreamed of but never successfully built.
A congratulatory telegram from Queen Victoria reached President James Buchanan at his summer home in the Bedford Springs Hotel in Pennsylvania, where she expressed hope that the cable would serve "an additional link between the nations whose friendship is founded on their common interest and reciprocal esteem." In response, the President said: "It is a triumph more glorious, because far more useful to mankind, than was ever won by conqueror on the field of battle. May the Atlantic telegraph, under the blessing of Heaven, prove to be a bond of perpetual peace and friendship between the kindred nations, and an instrument destined by Divine Providence to diffuse religion, civilization, liberty, and law throughout the world."
The messages sent across the Atlantic were difficult to read, and Queen Victoria’s message of 98 words took 16 hours to transmit. Still, the effort sparked excitement. The next morning, New York City welcomed the achievement with a 100-gun salute. Streets were decorated with flags, church bells rang out, and the city lit up at night. On 1 September, there was a parade, followed by a torchlight procession and fireworks that accidentally set off a fire in the Town Hall. Bright was honored with a knighthood for his role—the first time such recognition was given to anyone in the telegraph industry.
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The 1858 transatlantic cable project was already troubled by conflict between two key figures: Thomson and Whitehouse. Whitehouse, a medical doctor turned electrical enthusiast, had no formal physics training but relied on hands-on experience. The clash began before the project started, when Whitehouse challenged Thomson's law of squares presented at a British Association meeting in 1855. Thomson claimed transmission speed would be very slow due to retardation, but to test this, Bright let Whitehouse use the Magnetic Telegraph Company's underground lines for an experiment similar to the transatlantic route. Morse supported Whitehouse's results, while Thomson argued the measurements were flawed and that underwater cables weren't like underground ones. Thomson believed a larger cable was needed to reduce retardation. In mid-1857, he examined copper core samples and found resistance varied by up to two times, but since manufacturing had already begun, Whitehouse pushed for a thinner cable, and Field chose the cheaper option.
Another point of contention was the cable-laying plan. Thomson preferred starting in the middle of the Atlantic, with ships heading in opposite directions to cut time in half. Whitehouse wanted both ships to leave from Ireland together for progress reporting. Whitehouse overruled Thomson's 1857 idea, but Bright convinced directors to try the mid-ocean start again on 1858 voyage. As chief electrician, Whitehouse was supposed aboard the cable-laying ship but kept making excuses for 1857 trip, Bay of Biscay trials, and 1858 attempts. In 1857, Thomson went in his place, and in 1858, Field assigned men to different ships to avoid conflict—but since Whitehouse avoided the voyage, Thomson ended up going alone.
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After his work on the 1857 voyage, Thomson understood that detecting telegraph signals needed improvement. While waiting for the next trip, he created a new device called the mirror galvanometer, which was far more sensitive than anything before it. He asked for £2,000 to build several units but was only given £500 for one prototype and permission to test it on the upcoming journey. The instrument worked well at identifying the sharp edges of telegraph pulses—positive and negative signals that stood for Morse code dots and dashes. Thomson believed it could function with low voltages even across the full length of an Atlantic cable. He tested it successfully on 2,700 miles of underwater cable stored in Plymouth.
The mirror galvanometer created another dispute. Whitehouse favored using a large high-voltage induction coil to power the cable, generating thousands of volts so standard electromechanical printing telegraphs could function as they did on landlines. Thomson’s device, read only by eye, could not print. Nine years later, he developed the syphon recorder for the 1866 transatlantic effort. When the plan shifted to begin laying the cable mid-Atlantic and Whitehouse withdrew from another voyage, Thomson was aboard the Agamemnon heading to Ireland with full control over his equipment. Though his role was listed as advisor to engineer C. W. de Sauty, he soon made all the electrical decisions. Whitehouse remained in Valentia until the ship reached Ireland and completed the cable landing.
Around this time, the board began to question Whitehouse’s attitude. He had regularly disagreed with Thomson and also criticized Field. His repeated failures to fulfill his role as chief electrician aboard the ship left a poor impression. With Morse gone, Whitehouse lost his only supporter on the board, but no action was taken yet.
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When Agamemnon reached Valentia on 5 August, Thomson handed over to Whitehouse and the project was declared a success to the press. Thomson had received clear signals throughout the voyage using the mirror galvanometer, but Whitehouse immediately connected his own equipment. The cable's poor handling and design, along with Whitehouse's repeated attempts to push up to 2,000 volts through it, damaged the insulation. Whitehouse tried to hide the poor performance and was vague in his communications. The expected inaugural message from Queen Victoria had been widely publicised, and when it did not arrive, the press speculated that there were problems. Whitehouse said five or six weeks would be needed for "adjustments." The Queen's message had been received in Newfoundland, but Whitehouse couldn't read the confirmation copy sent back. Finally, on 17 August, he announced receipt. What he did not say was that the message had come through on the mirror galvanometer when he gave up using his own equipment. Whitehouse had the message reentered locally so he could send it on the printed tape and pretend it had been received that way.
In September 1858, after days of worsening insulation problems, the cable stopped working entirely. The reaction was huge—some said it was a fake, others called it a scam. Whitehouse was sent back for a board investigation, and Thomson took over in Valentia to figure out what had gone wrong, since Whitehouse had obscured the truth. Whitehouse was found at fault and removed from his position. The cable might have failed eventually anyway, but Whitehouse had sped that up. It was especially weak in the first hundred miles from Ireland, where the old 1857 cable had been joined to the new one—known to be poorly made. Tests showed the conductor was off-center in places and likely to break the insulation under stress. When tested underwater, a sample with even a tiny hole lit up like a lantern, and a bigger hole burned through the insulation completely.
The cable may never have been used for regular public service or functioned properly, but it still carried a number of real messages beyond simple tests. On 17 August, news of the collision between the Cunard Line ships Europa and Arabia was transmitted. The British Government later made use of the cable to cancel an order sending two regiments from Canada to England, saving £50,000. In August 1866, London stock markets began receiving quotes from New York via the Atlantic cable. Altogether, 732 messages were sent before the cable finally failed.
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Field didn’t give up after the first failure. He wanted to try again, but people had lost faith in the project, and his attempts to get support were useless. It wasn’t until 1864 that he finally gathered enough money, with help from Thomas Brassey and John Pender. The Glass, Elliot, and Gutta-Percha Companies came together to form the Telegraph Construction and Maintenance Company, known as Telcon, which would build and lay the new cable. C. F. Varley took over as chief electrician, replacing Whitehouse.
While earlier attempts were under way, cables had already been laid across the Mediterranean and the Red Sea, offering valuable experience. Engineers applied that knowledge to design a new cable. The core was made of seven twisted copper strands, each weighing 300 pounds per nautical mile, coated with Chatterton's compound, then wrapped in gutta-percha, with four layers of the material and four binding layers of the same compound. This brought the insulator weight to 400 pounds per nautical mile. The core was then covered with hemp saturated in a preservative solution, followed by eighteen single strands of high-tensile steel wire from Webster & Horsfall Ltd of Hay Mills Birmingham, each wrapped in fine manila yarn treated with preservatives. The finished cable weighed 35.75 long hundredweight per nautical mile—nearly twice as much as earlier versions. At the Hay Mills site, 250 workers produced 26,000 nautical miles of this new cable—1,600 tons—in eleven months.
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The second transatlantic cable was laid by the SS Great Eastern, under the command of Captain Sir James Anderson. The ship’s large hull had been modified with three iron tanks to hold 2,300 nautical miles of cable, and her decks were equipped with the necessary machinery for laying it. On 15 July 1865, at noon, the Great Eastern set sail from the Nore toward Foilhommerum Bay on Valentia Island, where the shore end was connected by the vessel Caroline. The mission ended in failure on 2 August, after 1,062 nautical miles had been laid—when the cable broke near the ship’s stern, and the end was lost.
Great Eastern returned to England, where Field released a new prospectus and created the Anglo-American Telegraph Company to lay a fresh cable and finish the broken one. On 13 July 1866, the ship began laying cable again. Though weather troubles delayed them on the evening of 27 July, the expedition reached Heart's Content, Newfoundland, in thick fog. Daniel Gooch, chief engineer of the Telegraph Construction and Maintenance Company, sent a message to Lord Stanley, Secretary of State for Foreign Affairs, saying, "Perfect communication established between England and America; God grant it will be a lasting source of benefit to our country." The next morning, at 9 a.m., a message from England quoted The Times: "It is a great work, a glory to our age and nation, and the men who have achieved it deserve to be honoured among the benefactors of their race." The shore end was landed that day by Medway at Heart's Content Cable Station. Congratulations poured in, and friendly telegrams were exchanged between Queen Victoria and the United States.
In August 1866, ships set sail again, including the Great Eastern, on a mission to recover the cable lost in 1865. Their aim was to locate the end of that cable, splice it with new wire, and finish the connection to Newfoundland. They were determined in their search, relying mostly on positions recorded by Captain Moriarty, R. N., who had placed the lost cable at longitude 38° 50' W.
Locating a cable two and a half miles down was like searching for a needle in a haystack. Robert Halpin, first officer of Great Eastern, guided HMS Terrible and the grappling ship Albany to where it lay. Albany used a five-pronged hook on a strong rope to fish for the cable, and on August 10, it finally "caught" the cable and brought it to the surface. But during the night, the cable slipped from its buoy, and the process started over. It happened several times as rough seas made things worse. A sailor was struck across the deck when the grappling rope snapped. Great Eastern and another ship, Medway, arrived on August 12 to help. Nearly two weeks later, in early September, the cable was finally retrieved and brought aboard, taking twenty-six hours. It was taken to the electrician's room, where it was confirmed connected. The damaged cable was spliced to a new one in the ship's hold and laid out to Heart's Content, Newfoundland, arriving on September 7. There were now two working lines.
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When a cable broke, fixing it meant following a careful process. The repair team first guessed where the break was by checking the cable’s resistance. Then they sailed to that spot. A grapple hooked the damaged section and pulled it aboard for testing. Buoys marked the good parts of the cable on either side of the break. Finally, workers made a splice to join the two ends back together.
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Messages were sent by an operator using Morse code, but the reception on the 1858 cable was very poor. Even with a highly sensitive mirror galvanometer, it took two minutes to send just one character—about 0.1 words per minute. The inaugural message from Queen Victoria took 67 minutes to reach Newfoundland, but it took 16 hours for the confirmation to travel back to Whitehouse in Valentia.
The 1866 cable marked a major leap in transatlantic communication, with both its construction and message transmission significantly improved. It carried eight words per minute—far faster than the 1858 version. Later, Oliver Heaviside and Mihajlo Idvorski Pupin identified that signal distortion occurred due to an imbalance between capacitive and inductive reactance, a problem described by the telegrapher's equations. This issue was eventually addressed using iron tape or load coils. It wasn’t until the 20th century that transatlantic cables reached speeds of 120 words per minute. London emerged as the global hub for telecommunications. From Porthcurno Cable Station near Land’s End, a network of cables spread out to form what became known as the All Red Line.
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After the first transatlantic cable was finished, additional lines were installed connecting Foilhommerum and Heart’s Content in the years 1873, 1874, 1880, and 1894. By the close of the nineteenth century, a dense network of telegraphic links had been established between Europe and North America. This system was supported by cables owned by companies based in Britain, France, Germany, and the United States.
The first transatlantic cable didn’t have repeaters, which might have fixed the signal delay problem and improved speed. Repeaters boost the signal along the line, something done with relays on land, but there was no practical way to power them underwater. The first submarine cable to use repeaters was TAT-1, put in place in 1956. It was a telephone cable, so it used a different kind of repeater technology than earlier telegraph cables.
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A study in the American Economic Review from 2018 looked at how the transatlantic telegraph changed trade and found that it really did make a difference. It showed that the telegraph connection led to a boost in Atlantic trade and helped lower prices. The researchers estimated that the efficiency gains from setting up the telegraph amounted to about 8 percent of export value.
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