History of the Atlantic Cable & Undersea Communications
of the Submarine Cable Industry in Britain
Submarine cable manufacture and laying began in Britain as one of the first electrical industries, shortly after the development of landline telegraphy. With no established theory or practice, the industry developed very much ad hoc, and this paper examines how materials and processes from other industries were adapted and improved as the cable business matured. The impact of the cable industry on electrical and signalling theory is also discussed.
The submarine cable industry in Britain progressed from infancy to maturity in just 15 years, between 1851 and 1866. 1851 marked the first successful international telegraph cable, from Dover to Calais. 1866 saw the first successful transatlantic cable, from Ireland to Newfoundland. In this 15 year period, telegraphic communication evolved from isolated national landline systems to a submarine cable network connecting much of the world. Britain was the cable industry’s hub and principal supplier, a position it would retain for over a hundred years.
A submarine communications cable has three primary components; the conductor, the insulation, and the armouring. Modern cables have a fiber-optic signal conductor, plastic insulation, and either plastic or stranded wire armouring, depending on the application. The physics, chemistry, and mechanical properties of each component are precisely defined, and the theoretical and practical performance of the cable can be well predicted.
At the beginning of the submarine cable era the requirements of a cable were essentially the same as today, but signalling theory had not been developed and no practice of cable manufacturing had been established. Electrical engineering did not exist as a profession; practitioners were known as “electricians” and based much of their work on experimentation. Materials were developed on a largely practical basis, and the needs of the cable industry were met in most cases by adapting existing products and techniques to new uses.
As cables were laid during the 1850s, the following requirements for a successful cable became apparent—sooner or, unfortunately in some cases, later:
A copper conductor of high purity and consistency, with good mechanical properties.
An insulating medium which could be readily sourced and easily worked, and which maintained its integrity in the pressure and temperature of the ocean depths.
A flexible outer armouring which would protect the conductor during the stresses of laying, prevent abrasion on the sea-bed and at the cable landing point, and be resistant to corrosion over the expected life of the cable.
And finally, a theory of operation, the need for which became critical as longer cables were developed.
We will now examine how the needs of the cable industry drove the evolution of each of these elements.
In the 1820s and 30s Faraday, Henry and other scientists made coils and electromagnets using what they described as “copper bell wire”. This wire was made not for electric bells, which did not yet exist, but for the mechanical system of bells used to call the servants in the houses of the well-to-do. The copper bell wire was number 14 Birmingham Wire Gauge (B.W.G.), and was insulated with silk or cotton using the methods of the milliners, who covered iron wire with silk for “bonnet wire”. In 1835 W. Ettrick designed a machine for covering wire, which was reported in 1837 as being able to produce 400 feet per hour of insulated wire.
Meanwhile, Charles Wheatstone had been experimenting with the transmission of electrical pulses over long lengths of copper wire, initially using half a mile of wire suspended in the vaults under Kings College, London. In 1836 he demonstrated transmission over 4 miles of wire, and showed the possible use as a telegraph by the deflection of a galvanometer at the end of the circuit. Several patents on signalling through metallic circuits followed, and by 1840 Cooke and Wheatstone’s telegraph systems were in use in a number of areas. Their early telegraph lines used copper wires held in grooved wooden blocks, but landline telegraphs eventually used the much cheaper iron wire, whose tensile strength made it more suitable for overhead lines.
During the 1840s, Wheatstone and others began to consider the possibility of submarine cables. By 1846 Wheatstone had devised a lead covered cable, the copper conductor being insulated with marine glue and cotton, but apparently did not pursue the project any further.
In 1849 the Brett brothers formed the English Channel Submarine Telegraph Company, and ordered 25 miles of copper wire from Thomas Bolton & Sons in Birmingham. Bolton’s was a traditional wire-drawing firm, established in 1783, and the copper wire they produced for the Bretts was the standard number 14 B.W.G. bell wire. At that time there was no standard for electrical wire, and the bell wire was drawn in the same way as wire from any other metal. The use of different sources of copper resulted in widely varying conductivity from batch to batch, and the wire was supplied in short lengths of only 100 yards, which had to be jointed and soldered to make the required length for the cable. Willoughby Smith described the wire as varying in any one length through “hard, brittle, soft and rotten”. The conductivity of the cable was measured at only 30%, compared with 100% for pure copper. In defense of Bolton’s, the Bretts had made no particular specification of electrical or mechanical properties for the wire.
The Bretts’ cable, which was laid in 1850 without armouring, soon failed. Undeterred, they engaged Thomas Crampton, who also put up half the £15,000 cost, to lay a second cross-channel cable in 1851. This cable’s conductivity was still only 40%, but this was adequate over the short length used, and the success of this cable began the commercial submarine cable era. Other cables soon followed, and the quality of the copper wire began to improve. This was partly due to the refinement of the manufacturing processes at the wire drawers: as longer continuous lengths of wire were produced, it was found that drawing these longer sections required a better mechanical quality in the copper, and copper which could be well-drawn also had a higher conductivity. When the wire for the 1857 Atlantic Cable was supplied, the length of the individual sections had increased to one mile.
William Thomson had been interested in submarine telegraphy from its inception, and performed extensive research into the production of copper wire for cables. He suggested using a stranded conductor, which would be more flexible than a single wire, and would protect against complete signal loss should one or more of the conductors fracture. Such a stranded conductor was first used in the 1857 Atlantic Cable, which was made with seven number 22 B.W.G. wires, requiring almost 120 tons of copper formed into twenty thousand miles of wire. However, conductivity was still a problem. Thomson’s tests on wire samples from four different manufactures showed considerable variation in conductivity from sample to sample, some samples having twice the resistance of others.
After the failure of the 1857 cable expeditions, Thomson continued his work on copper wire in his laboratory at Glasgow University. While he had not yet determined the reason for the cause of the variability, he specified for the additional cable made for the 1858 expedition the use of “high conductivity” copper wire. In March 1858 Thomson received the results of a precise chemical analysis of five specimens of copper wire, and determined that the variations in conductivity were caused not by the mechanical treatment of the copper, but by impurities in the different ores from which the copper was smelted. By 1864 other researchers had made a comprehensive analysis of the ores used by British smelters, finding the conductivity of copper from the worst ore to be about 14%, and the best to be over 92%.
Full advantage was taken of this research to improve the quality of submarine cable wire, and by the time Bolton’s made the copper wire for the 1865 and 1866 cables a much higher standard of consistency was achieved, and the wire proved more than adequate for its purpose.
The first electrical insulation was silk or cotton thread wrapped around the conductor. This was adequate for wires, coils and instruments to be used on land, but not suitable for the underwater environment. Early submarine cable experimenters used india-rubber, cotton saturated with pitch and resin, and tarred rope covered with pitched yarn, all with limited success. By 1846 the Siemens brothers in Germany were using gutta percha to insulate underground cables, and in 1848 they used a submarine cable in Kiel harbour to fire submarine mines.
In 1849 Charles Walker, telegraph superintendent of the South-Eastern Railway Company, laid two miles of gutta percha insulated cable in Folkestone harbour, and transmitted signals through it and 83 miles of land line to London. After the success of this experiment, Walker proposed a cable from Folkestone to Boulogne, but nothing came of this. In 1851, following their failure in 1850 with the unarmoured cable using gutta percha insulation, the Bretts laid the successful Dover to Calais cable, the first to use an armoured outer layer, with two layers of gutta percha insulation.
Gutta percha proved to be an ideal insulator for submarine cables, remaining the prime material for over 80 years. Introduced to Britain in 1843, gutta percha is the gum of a tree native to the Malay Peninsula and Malaysia. At that time there was no application for the material as insulation; this would come later. Unlike india rubber, which must be vulcanised to be useful as an insulator, gutta percha is thermoplastic, softening at elevated temperatures and returning to its solid form as it cools. This made it easy to mould gutta percha into many decorative and functional objects, either by pressing the heated material into cold moulds, or by extrusion. As a further benefit for cable use, it was found that gutta percha’s insulating properties improved under the pressure and temperature conditions of the ocean bed.
The Gutta Percha Company was established in 1845, and made chessmen, mirror surrounds, tea trays, commemorative plaques, animal figures, inkstands, and even a full-size sideboard, among many other decorative items. Industrial products included machinery belts, acid-tank linings, and tubes. The extrusion machinery used to make the tubes, modelled it is said on Italian pasta machines, was soon adapted for use in wire covering. This technique was used first to insulate landline cables, and later for submarine cables.
Previous attempts to use gutta percha as cable insulation involved compressing two sheets of gutta percha around the wire, but this left two seams in the insulation. The Gutta Percha Company’s tubes were seamless, and proved their value in insulating the 1850 and 1851 cross-channel cables, although the covering process had not yet been perfected. The conductors of the 1851 cable had an irregular coating of gutta percha, which had to be shaved away in places, and suffered from air holes and voids. Nonetheless, the cable was a success, and much additional business followed. Producing cable core became the company’s main operation, consuming a significant proportion of the output of gutta percha, imports of which exceeded a thousand tons a year by 1861.
The Gutta Percha Company had few competitors during the 1850s, and supplied the bulk of the cable core in the early years of the industry, including that for the 1857 and 1858 Atlantic cables. By the time of the 1865 Atlantic cable, the company had supplied over 14,000 miles of core for 64 cables, and production of reliable and consistent cable core was routine. One of their major customers was cable manufacturer Glass, Elliot & Company, formed in 1854, which had made many cables, including the 1857 and 1858 Atlantic cables. To meet the financial and engineering demands of the 1865 cable, the Gutta Percha Company amalgamated with Glass, Elliot to form the Telegraph Construction and Maintenance Company. Known as Telcon, this was the first company to be involved in every phase of cable making, from insulating the core to laying the completed cable.
Gutta percha proved to be such a well-suited material for insulating submarine cables that it was used almost exclusively until finally superseded by polythene in the early 1930s.
As was shown by the early failure of the 1850 channel cable, armouring was essential to the longevity of submarine cables. Armouring serves two purposes; it gives the cable integrity and structural strength to resist the stresses of laying, and it protects the installed cable from marine predators, chafing on rocks, and ships’ anchors. The first armoured cable, the 1851 channel cable, used four strands of number 16 copper wire insulated with a double layer of gutta percha. These were assembled into a square cross-section with the gaps filled with tarred hemp, and a spiral wrap of ten galvanised iron wires completed the cable. The overall diameter of the cable was 1¼ inches, and the weight was between 7 and 8 tons per mile. Other cables which followed used variations of this construction, but all had spiral wrapped armouring.
As in other areas, the machinery, materials, and techniques used to make the cable core into an armoured cable ready for laying came from another industry entirely—wire rope manufacture, which began in the 1830s in both Britain and Europe. The impetus for producing a replacement for the traditional hemp and other fiber ropes came from the mining industry. Most of Europe’s energy was supplied by burning coal, and, unlike in the United States where coal was found near the surface, Europe’s coal came from deep mines. This required moving men and coal through vertical shafts often several thousand feet deep, and safe operation of heavy loads at these depths was not possible with hemp ropes.
The first wire ropes were made with iron wire, using the same manufacturing methods as for hemp rope. By 1834 wire ropes developed by the German engineer Wilhelm Albert were being used in the mines in Germany’s Upper Harz district, and it was estimated that the additional manufacturing cost was more than covered by the much longer life of the wire rope over traditional hemp ropes. The new technology spread rapidly to Britain, and by the late 1830s there were a number of companies making wire rope.
In 1837 Lewis Gordon, formerly an assistant to Brunel during the construction of the Thames Tunnel, made a career change to practical mining and entered the Freiburg School of Mines in Germany, and then the École Polytechnique in Paris. In 1838 he visited the mines at Clausthal in the Harz mountains, and met Wilhelm Albert. Impressed by what he saw, he wrote to his friend R.S. Newall in Britain, urging him to “Invent a machine for making (wire ropes)”. Newall was to become a key figure in submarine cable manufacturing, but this still lay 12 years in the future.
Robert Sterling Newall was born in Dundee, Scotland, in 1812 and in 1838 he was proprietor of an engineering works in that city. On receipt of Gordon’s letter, Newall set to designing a wire rope machine, and by the end of July he had sent Gordon a drawing of a machine which would produce a wire rope of four strands and four wires to a strand. On Gordon’s return from Germany in 1839, he formed a partnership with Newall and Charles Liddell. In August 1840 Newall took out a patent for “certain improvements in wire rope and the machinery for making such rope”, and immediately following this the three partners established themselves as R.S. Newall and Company in Dundee, and commenced making wire ropes for “Mining, Railway, Ships’ Rigging, and other purposes”. An important feature of Newall’s wire rope was a central core of hemp or other flexible material, which allowed the individual wires and strands to be held equidistant from their respective centers, ensuring equal stress on each wire.
After the Dover to Calais cable failed in August 1850, a pamphlet written by Robert McCalmont in September of that year refers to Newall and states: “He proposes that the gutta percha lines containing an insulated wire should be surrounded with strong wire rope; that a rope of gutta percha cords, with their insulated wire wicks, should, in fact, constitute the core of a strong wire cable, to be laid at the bottom of the sea”.
There is some dispute whether Newall in fact originated this idea of a cable within a wire rope. Newall himself made a not very definite remark claiming credit in a letter to the Times in 1852, but did not make the claim firmly until he published a pamphlet on the subject in 1882. Newall states that in September 1850 he submitted a specimen of his cable to the engineer of the Anglo-French Telegraph Company, on the understanding that Newall and Company were to get the contract for manufacturing it. The Anglo-French Company, however, in July 1851 let the contract to Edward Weatherley, who had made modifications to the wire rope machinery to evade Newall’s patent. Newall obtained an injunction, and forced the Anglo-French Company to come to him to manufacture the cable, as they were under time constraints by the terms of their cable-laying concession. Newall and Company completed the contract by hiring Weatherly’s factory and using Newall employees to produce the cable, which was successfully laid in September 1851.
Their initial success in submarine cable manufacturing led R.S. Newall and Company to expand this part of their operation to deal with cable laying as well as manufacture. In 1852 the company made and laid the Holyhead to Howth and Port Patrick to Donaghadee cables, and in 1853 the Dover to Ostend and Firth-of-Forth cables. In November 1854 during the Crimean war the company filled an urgent order to supply and lay a cable from Varna to Sebastopol, the “Black Sea Cable”. The cable core was supplied to Newall by the Gutta Percha Company, and Newall delivered and laid the cable in record time. Curious as to how Newall achieved this almost immediate delivery, competitors had to wait until the cable had been laid to discover that only the shore ends were protected inside a cable sheath; the remainder of the wire being laid with only the gutta percha insulation to protect it. Despite this, the cable gave good service for nearly a year.
Newall soon had competitors in the lucrative cable business, one of which rapidly overtook him. Glass, Elliot, which achieved prominence in the cable industry after the successful laying of the Atlantic cables, was founded by George Elliot. Elliot was born in 1815 in Gateshead, the son of a coal miner, became a mining engineer, and in 1840 a colliery owner. In this capacity he dealt with the wire rope manufacturer Kuper and Company of Camberwell, London, becoming their sole agent and manager after their bankruptcy in 1849. He moved the works to Morden Wharf, East Greenwich, and by 1854 he was proprietor of the company, paying off the creditors and the original members of the firm. In that same year Elliot joined in partnership with Richard Glass, and the firm was renamed Glass, Elliot and Company, and began producing submarine cables. As already described, the company’s merger with the Gutta Percha Company in 1864 made it a dominant force in the cable industry for the next hundred years.
A third significant cable company which arose from the wire rope business was that of W.T. Henley. Henley started as an instrument maker, supplying Charles Wheatstone’s needs and providing landline telegraph instruments to the Electric Telegraph Company. As his business developed he moved from Whitechapel to Clerkenwell and then to Enderby’s Wharf at Greenwich, where he took over the premises of Enderby’s Hemp Rope Works and began manufacturing cables. Henley shared the factory with Glass, Elliot, and Company, but disputes soon arose between the two competitors, and Henley set up a new factory on the opposite side of the Thames at North Woolwich. Henley initially purchased his core from the Gutta Percha Company. As well as making cables for his own customers, Henley later produced sub-contracted orders for Telcon.
The early cables were laid without regard to theory of operation. If a signal injected at one end could be read at the other end, the cable was considered a success. As longer cables were made, the limitations of this approach became evident, culminating in the transmission problems and early failure of the 1858 Atlantic cable.
The theory of signal propagation in undersea cables was developed initially by Michael Faraday, who showed that a cable under water acted as a large capacitor, retarding the transmission of the signal impulses. William Thomson then showed that the retardation was proportional to the square of the cable’s length, and that although the effect could be mitigated by using the highest conductivity copper and good insulation, satisfactory signalling speeds would require new transmission techniques. These theories were largely ignored by the Atlantic Telegraph Company’s chief electrician, Wildman Whitehouse, who attempted to overcome the 1858 cable’s inherent limitations by using very high voltages, eventually causing a complete failure of the insulation. Whitehouse’s engineering shortcomings notwithstanding, it is likely that the insulation of some sections of the cable had been compromised even before it was laid, as the 1858 expedition re-used large parts of the 1857 cable, which had been left lying in the sun for a considerable time.
Problems with the 1857 cable also pointed out the need for a code of practice, or at least for written specifications. The manufacture of the cable was divided between Newall’s in Birkenhead and Glass, Elliot in London. Newall’s armoured the cable with a right-hand lay, Glass, Elliot with a left-hand lay. Splicing the opposing lays in mid-ocean required an elaborate fixture.
The failure of the 1858 cable, with the loss of the considerable investment of over a million pounds, and other expensive failures in the same period, led to the formation of the Joint Committee Appointed by the Lords of the Privy Council for Trade and the Atlantic Telegraph Company to Inquire into the Construction of Submarine Telegraph Cables. Half its members were nominated by the Board of Trade, half by the Atlantic Telegraph Company. The committee met for ten months, from December 1859 to September 1860, and heard evidence from what must have been almost every scientist, engineer, and manufacturer who had ever been involved in the cable industry. The eighty thousand word report of the committee, published in 1861, is a comprehensive survey of cable theory and practice, presenting much quantitative work on the subject. The opinion of the committee was generally optimistic, their conclusion being that the 1858 cable “failure was due to causes which might have been guarded against had adequate preliminary investigation been made.”
The report must be rated as one of the earliest rigorous scientific studies, perhaps the first, of a major industry. It offered insights not just into the failure of the cable, but also into the state of the art of electricity and telegraphy in general, and its conclusions laid the foundation for the ensuing success of long-distance submarine cables.
Much of the analysis provided in the evidence to the committee was performed by scientists and engineers such as Charles Bright, Samuel Canning, Latimer Clark, Fleeming Jenkin, C.W. Siemens, Willoughby Smith, William Thomson, and Cromwell Varley. These men and others also developed the instruments and techniques which contributed to the practical operation of long lines, acting as consultants and suppliers to the cable industry.
With the theoretical basis of signal transmission established, new instruments available, the purity of the copper and gutta percha improved, and cable construction and laying methods refined, the promoters of the 1865 Atlantic cable expedition went into it with a confident approach. Despite the breakage of the cable, and the subsequent failure to recover it because of limitations in the grappling equipment, the 1865 expedition was not viewed as a loss. In a letter written on board the Great Eastern after the unsuccessful recovery attempts, Daniel Gooch said: “There is no doubt the cable will be raised, joined and completed” and “The Captain & all of us are quite satisfied a cable can be laid with this ship in any weather.” He was proved correct by the 1866 cable expedition, which laid the cable from Ireland to Newfoundland without incident, then recovered and completed the 1865 cable.
Just 15 years after the cross-channel cable of 1851, the era of worldwide communications had begun, and for the many industries supplying and supporting the cable industry the making and laying of long cables became routine.
Blake-Coleman, B.C. Copper Wire and Electrical Conductors—The Shaping of a Technology. Reading: Harwood Academic Publishers, 1992.
Bright, Charles. Submarine Telegraphs, Their History, Construction and Working. London: Corsby Lockwood, 1898.
Forestier-Walker, E.R. A History of the Wire Rope Industry of Great Britain. N.P.: Federation of Wire Rope Manufacturers of Great Britain, 1952.
Haigh, K.R. Cableships and Submarine Cables. London: Standard Telephones & Cables Limited, 1978.
Lawford, G.L. & Nicholson, L.R. The Telcon Story. London: The Telegraph Construction & Maintenance Co. Ltd., 1950.
Morton, John. Thomas Bolton & Sons Limited, 1783-1983. Ashbourne: Moorland Publishing, 1983.
Newall, R. S. Facts and Observations Relating to the Invention of the Submarine Cable. London, 1882.
Last revised: 21 December, 2019