The transatlantic telegraph cable was the first cable used for telegraph communications laid across the floor of the Atlantic Ocean. It crossed from the Telegraph Field, Foilhommerum Bay, Valentia Island, in western Ireland to Heart's Content in eastern Newfoundland. The transatlantic cable bridged North America and Europe, and expedited communication between the two. Whereas it would normally take at least ten days to deliver a message by ship, it now took a matter of minutes by telegraph.
Five attempts to lay it were made over a nine-year period‚ÄĒin 1857, two in 1858, in 1865, and in 1866‚ÄĒbefore lasting connections were finally achieved by the ship 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 between Europe and the Americas could only happen by ship, the transatlantic cable sped up communication to within minutes, allowing an inquiry and a response 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 to US dollar exchange rate came to be referred as "cable" and this term is still in common usage today.. The great utility of the cable built on itself, and multiple cables were established soon afterward.
After William Cooke and Charles Wheatstone introduced their working telegraph in 1839, the idea of a submarine line across the Atlantic Ocean began to be thought of as a possible triumph of the future. Samuel F. B. Morse proclaimed his faith in it as early as the year 1840 and the following decade saw a period of experimentation and growth of knowledge in underwater telegraph cables culminating in the 1850 link between England and France. That same year, Bishop John T. Mullock, head of the Roman Catholic Church in Newfoundland, proposed a line of telegraph through the forest from St. John's to Cape Ray, and cables across the mouth of the St. Lawrence River from Cape Ray to Nova Scotia across the Cabot Strait.
At about the same time, a similar plan occurred to Frederick Newton Gisborne, a telegraph engineer in Nova Scotia. In the spring of 1851, Gisborne procured a grant from the legislature of Newfoundland, and having formed a company, began the construction of the landline. However, in 1853 his company collapsed. He was arrested for debt and lost everything. The following year, he was introduced to Cyrus West Field. Field invited Gisborne to his house to discuss the project. From his visitor, Field extended the idea that the telegraph to Newfoundland might be extended across the Atlantic Ocean.
Field was ignorant of submarine cables and the deep sea. He consulted Morse as well as Lieutenant Matthew Maury, an authority on oceanography. Field adopted Gisborne's scheme as a preliminary step to the bigger undertaking, and promoted the New York, Newfoundland and London Telegraph Company to establish a telegraph line between America and Europe.
The first step was to finish the line between St. John's and Nova Scotia, and in 1855 an attempt was made to lay a cable across the Cabot Strait in the Gulf of Saint Lawrence. It was laid out from a barque in tow of a steamer. When half was laid a gale rose and, to keep the barque from sinking, the line was cut away. Next summer a steamboat was fitted out for the purpose and the link from Cape Ray, Newfoundland to Aspy Bay, Nova Scotia was successfully laid.
Field then directed the efforts to the transoceanic section with Charles Tilston Bright as chief engineer. A special survey was made along the proposed route of the cable and revealed that the proposed route was possible. Funds were raised from both American and British sources by selling shares in the Atlantic Telegraph Company. Field himself supplied a quarter of the needed capital.
The cable consisted of seven copper wires, each weighing 26 kg/km (107 pounds per nautical mile), covered with three coats of gutta-percha, weighing 64 kg/km (261 pounds/nautical mile) and wound with tarred hemp, over which a sheath of eighteen strands, each of seven iron wires, was laid in a close spiral. It weighed nearly 550 kg/km (1.1 tons per nautical mile), was relatively flexible and able to withstand a pull of several tens of kilonewtons (several tons). It was made jointly by two English firms‚ÄĒGlass, Elliot & Co., of Greenwich, and R. S. Newall & Co., of Liverpool.
The British Government gave Field a subsidy of ¬£1,400 a year and loaned the ships to lay the cable. Field solicited aid from the United States Congress; the vote was very close with a number of anglophobe senators opposing any grant. The Bill was passed by a single vote. In the House of Representatives it encountered a similar hostility, but was ultimately signed by President Franklin Pierce.
The first attempt, in 1857, was a failure. The cable-laying vessels were the converted warships HMS Agamemnon and USS Niagara. The cable was started at the white strand near Ballycarbery Castle County Kerry, the southwest coast of Ireland, on August 5, 1857. The cable broke on the first day, but was grappled and repaired; it broke again over the 'telegraph plateau,' nearly 3,200 m (2 statute miles) deep, and the operation was abandoned for the year.
The following summer the Agamemnon and Niagara, after experiments in the Bay of Biscay, tried again. The vessels were to meet in the middle of the Atlantic, where the two halves of the cable were to be spliced together, and while the Agamemnon paid out eastwards to Valentia Island the Niagara was to pay out westward to Newfoundland. On June 26, the middle splice was made and the cable was dropped. Again the cable broke, the first time after less than 5.5 km (three nautical miles), again after some 100 km (54 nautical miles) and for a third time when about 370 km (200 nautical miles) of cable had run out of each vessel.
The expedition returned to Queenstown and set out again on July 17 with little enthusiasm amongst the crews. The middle splice was finished on July 29, 1858. The cable ran easily this time. The Niagara arrived in Trinity Bay, Newfoundland on August 4 and the next morning the shore end was landed. The Agamemnon made an equally successful run. On August 5, the Agamemnon arrived at Valentia Island, and the shore end was landed at Knightstown and then laid to the nearby cable house.
On August 16, the first message sent across the cable was, "Glory to God in the highest; on earth, peace and good will toward men." Then Queen Victoria sent a telegram of congratulation to President James Buchanan through the line, and expressed a hope that it would prove "an additional link between the nations whose friendship is founded on their common interest and reciprocal esteem." The President responded that, "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."
These messages were the signal for an outburst of enthusiasm. Next morning a grand salute of 100 guns resounded in New York City, the streets were decorated with flags, the bells of the churches rung, and at night the city was illuminated . The Atlantic cable was a theme for innumerable sermons and a prodigious quantity of doggerel.
In September, after several days of progressive deterioration of the insulation, the cable failed. The reaction at this news was tremendous. Some writers even hinted that the line was a mere hoax, and others pronounced it a stock exchange speculation.
Field was undaunted by the failure. He was eager to renew the work, but the public had lost confidence in the scheme, and his efforts to revive the company were futile. It was not until 1864 that with the assistance of Thomas Brassey and John Pender he succeeded in raising the necessary capital. The Glass, Elliot, and Gutta-Percha Companies were united to form the Telegraph Construction and Maintenance Company (Telcon, later part of BICC), which undertook to manufacture and lay the new cable. C.F. Varley replaced Whitehouse as chief electrician.
Much experience had been gained in the meantime. Long cables had been submerged in the Mediterranean and the Red Sea. With this experience an improved cable was designed. The core consisted of seven twisted strands of very pure copper weighing 300 lb per nautical mile (73 kg/km), coated with Chatterton's compound, then covered with four layers of gutta-percha, alternating with four thin layers of the compound cementing the whole, and bringing the weight of the insulator to 400 lb/nmi (98 kg/km). This core was covered with hemp saturated in a preservative solution, and on the hemp were spirally wound eighteen single wires of soft steel, each covered with fine strands of manila yarn steeped in the preservative. The weight of the new cable was 35.75 long hundredweight (4000 lb) per nautical mile (980 kg/km), or nearly twice the weight of the old.
The new cable was laid by the ship Great Eastern captained by Sir James Anderson. Her immense hull was fitted with three iron tanks for the reception of 2,300 nautical miles (4260 km) of cable, and her decks furnished with the paying-out gear. At noon on July 15, 1865, the Great Eastern left the Nore for Foilhommerum Bay, Valentia Island, where the shore end was laid by the Caroline. This attempt failed on July 31 when, after 1,062 miles (1968 km) had been paid out, the cable snapped near the stern of the ship, and the end was lost.
The Great Eastern steamed back to England, where Field issued another prospectus, and formed the Anglo-American Telegraph Company, to lay a new cable and complete the broken one. On July 13, 1866, the Great Eastern started paying out once more. Several times in unrolling the cable they observed that nails had been recently forced into it, evidently with the motive of destroying it. Captain Anderson had it posted up that if the offender were caught on board, he would be thrown into the sea without further trial. From then on the criminal act was not repeated. Despite problems with the weather on the evening of Friday, July 27, the expedition reached the port of Heart's Content in a thick fog. The next morning at 9 a.m. a message from England cited these words from the leader in 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." "Treaty of peace signed between Prussia and Austria." The shore end was landed during the day by the Medway. Congratulations poured in, and friendly telegrams were again exchanged between Queen Victoria and the United States.
On August 9 the Great Eastern put to sea again in order to grapple the lost cable of 1865, and complete it to Newfoundland. They were determined to find it. There were some who thought it hopeless to try, declaring that to locate a cable two-and-a-half miles down would be like looking for a small needle in a large haystack. For days, the Great Eastern moved slowly here and there, "fishing" for the lost cable with a grapnel at the end of a stout rope. Suddenly, the cable was "caught" and brought to the surface, but while the men cheered it slipped from the grapnel's hold and vanished again. It was not until a fortnight later that it was once more fished up; then it took 26 hours to get it safely on board the Great Eastern. The cable was carried to the electrician's room where it was determined that the cable was connected. All on the ship cheered or wept as rockets were sent up into the sky to light the sea. The recovered cable was then spliced to a fresh cable in her hold, and paid out to Heart's Content, Newfoundland, where she arrived on Saturday, September 7. There were now two working telegraph lines.
Initially messages were sent by an operator sending Morse code, a series of dots and dashes. The reception was very bad on the 1858 cable, and it took 2 minutes to transmit just one character (a single letter or a single number), which translates to about 0.1 words per minute. This is despite the use of a highly sensitive mirror galvanometer, a new invention of the time.
The first message on the 1858 cable took over 17 hours to transmit. For the 1866 cable, the methods of cable manufacture, as well as sending messages, had been vastly improved. The 1866 cable could transmit eight words a minute ‚ÄĒover 50 times faster than the 1858 cable. Heaviside and Mihajlo Idvorski Pupin in later decades understood that the problem was an imbalance between capacitive and inductive reactance, to be solved by iron tape or by load coils. It was not until the 20th century that message transmission speeds over transatlantic cables would reach even 120 words per minute. Despite this, London had become the world centre in telecommunications. Eventually, no fewer than 11 cables radiated from Porthcurno Cable Station near Land's End and formed with their Commonwealth links a "live" girdle around the world.
The original cables were not fitted with relays, which would have amplified the signal along the way. This was because there was no practical way to power the relays. As technology advanced, intermediate relays became possible.