Without the Great Eastern, the only possible solution was to use two ships. But even the largest vessels in existence could not carry 1,250 miles of cable if it weighed more than a ton a mile. It was essential that the cable was as strong as possible, to guard against accident – but while it could not be too strong, it may be too bulky, too heavy or too light. It must also be flexible enough to coil in the factory and in storage, and to be easily handled through the sheaves of the paying-out machinery. The copper core had to be of sufficient quality and purity to transmit long-distance signals, and the insulation needed to withstand the weight and forces of the Atlantic deeps. The specification finally agreed was for a pure copper wire, twisted from seven strands and about a sixteenth of an inch in diameter. It was designed to stretch by twenty per cent without breaking, and even if strands were broken at different points could continue to conduct electricity. When coated with three layers of gutta percha, the diameter became about three-eighths of an inch, rather larger than previous submarine cables.
By the time the Atlantic crossing was planned, submarine cable manufacture had become much better organised and regulated, in the hope of avoiding some of the calamities of the early projects. Once coated with gutta percha, two-mile lengths of the core were immersed in water and carefully tested for faults. These tests were made with a galvanometer, a sensitive instrument which could detect whether a current passed through the wire. After being joined into sections of about 100 miles, the cores were sent to another factory for armouring. A layer of hemp and tar protected the gutta percha from damage by the outer coating, the armour itself.
The armour’s main function was to protect the cable from ‘mechanical violence’, although it also gave scope to make the line heavier or lighter, as appropriate for particular circumstances. It shielded against damage during paying out, and guarded the cable from accidental harm by anchors or fishing lines or rocks once it was laid. On each submarine telegraph there were two, more heavily armoured, shore-end cables which were spliced to the main cable some miles out at sea where the risks of accidental damage became much lower. For the Atlantic cable, there were to be ten miles of shore-end cable at the Trinity Bay end, and fifteen miles off the coast of Ireland. These parts of the cable weighed seven tons a mile, more than seven times as much as the main section. The engineers expected that the iron coating of the main cable would eventually be consumed by rust, but once the cable was on the ocean floor this did not matter, as the gutta percha-coated core was designed to withstand the pressure of water and to survive independently.
Charles Tilson Bright. (Cable & Wireless Archives, Porthcurno)
Charles Bright and Wildman Whitehouse, who had made Field’s acquaintance in London in 1855, were appointed to the Atlantic company: Bright as engineer and Whitehouse as electrician. Bright, only twenty-five years old in 1857, had started his telegraph career ten years earlier under Cooke. He rose to become engineer of the Magnetic Telegraph Co. by the age of twenty, and was involved in laying the first successful cable between Scotland and Ireland the following year. He made a large personal investment in the Atlantic scheme at the outset. Wildman Whitehouse, a Brighton surgeon long fascinated by electricity, was associated with John Brett during the laying of the Channel cable. By 1854 he had virtually abandoned medicine to devote his time to electrical experimentation.
Even before they joined the Atlantic company, Bright and Whitehouse had been preoccupied with the twin problems of whether it was indeed possible to transmit an electrical current across 2,000 miles of ocean, and if so, whether signals could be sent and received at a commercially viable rate. They spent much of the middle years of the 1850s working on these questions.
Experimenters would seize on any chance for trials. In 1855, when two long cables had been completed in the Greenwich factory, a line of 1,146 miles could be constructed by linking them together. The results were exciting. Until then, there had been genuine doubts that an electrical signal could be transmitted at all along a cable of such length. Within moments there came an answer: a trace appeared at the far end of the line. It could no longer be denied that the signal would travel 1,000 miles at least. But the signs were not entirely good. The current, transmitted along the cable as a series of beats, was received as one long continuous line.
In the autumn of 1856, Bright, Whitehouse and Morse set out to prove without doubt that it was possible to send a signal down 2,000 miles of telegraph line, and do it at a speed which would make the Atlantic cable economically viable. Morse had emphasised all along that the Atlantic scheme must be practicable, that is, that it could be achieved technically, but he believed it should also be practical; in other words, sensible and to the advantage of those proposing it. The American travelled to London to meet Bright and Whitehouse, whom he described as ‘that clear-sighted investigator of electrical phenomena’, at the offices of the English & Irish Magnetic Telegraph Co. Bright had arranged a night-time experiment in which ten gutta percha-insulated underground lines, each of more than 200 miles, would be linked. This trial would mimic the transatlantic cable as closely as possible, not only in length, but also because subterranean lines closely resembled submarine cables in their electrical properties.
These underground cables were already in commercial use, so that Morse and his ‘active and agreeable collaborators’ had to conduct their trial at dead of night, when the office was closed. Bleary-eyed after a full night of testing, during which the electricians were able to transmit up to 270 signals a minute in conditions which were far from ideal, Morse concluded that the distance was in both respects – of practicability and practicality – viable. Having slept on it, he wrote to Field, estimating that eight to ten words a minute, or twenty messages an hour, could be sent between Ireland and Newfoundland. This amounted to 480 cables a day, and that on a single wire. Morse thought that this rate could be doubled by further improvements in signalling, in particular a more refined code, but, he concluded, ‘the doubts are resolved, the difficulties overcome, success is within our reach and the great feat of the century must shortly be accomplished.’
Doubts persisted, though, about managing this rate of transmission on the line itself. This was a real threat to the cable’s profitability. The slower the speed at which messages could be sent, the more astronomical would be the cost of each telegram, and the lower the return to shareholders. After Morse’s triumphant note to Field, Bright and Whitehouse continued their experiments. The best explanation for delayed signals that they could advance was that the conducting wire did not discharge itself between beats. ‘The current moved so sluggishly and unwillingly in this protracted and induction-encumbered channel, that one transmission was not able to clear itself off, before the next was pressing upon its heels, and in confusion with it.’
A solution to the retardation dilemma began to emerge, not from the practical experiments of Whitehouse, but from an altogether more theoretical realm. Key to these developments was William Thomson, later Lord Kelvin, who built on Faraday’s work. Thomson was professor of Natural Philosophy at the University of Glasgow, and an associate of R.S. Newall and his partners, Lewis Gordon and Charles Liddell. Thomson convinced Gordon that ‘scientific deductions from established principles’ were a reliable and economical method of advancing submarine telegraphy – much more so, in fact, than expensive practical trials from which even the best engineers could draw mistaken inferences. Working purely from theory, Thomson produced graphs showing that a pulse that started out more or less rectangular in form would emerge from an insulated cable rounded and elongated.
Thomson’s theoretical work proved that the speed of signals depended on three things – the length of the cable, and the properties of the copper conductor and of the insulator. Of these three variables, cable length was the most significant. Retardation of the signals was, he concluded, in proportion to the square of the cable’s length – Thomson’s ‘Law of the Squares’. It was possible to increase the speed significantly by making t
he copper core larger, but this brought with it other difficulties. It made the cable bulkier and heavier, so that bigger ships, heavier paying-out machinery and larger cable-making machinery were needed. All these had an impact on costs, and brought further questions about the economic viability of transoceanic telegraphy. Otherwise, physically, there was little else to do to improve the cable. Reducing impurities in the copper core would increase conductivity, but the gains were small. As for the insulator, nothing had been found which could come close to the performance of gutta percha.
While Thomson and others in his circle were convinced by the ‘Law of the Squares’, Wildman Whitehouse would not accept it. He went so far as to produce experimental results in support of his view, at a meeting in 1856 of the prestigious British Association for the Advancement of Science. Thomson could not verify his law by experiment because, while input signals could be timed precisely, it was much more difficult to measure exactly the exit signals. Later it emerged that Whitehouse’s measurements were flawed. It was not until 1859 that Fleeming Jenkin, who worked closely with Thomson, produced a clear proof of the ‘Law of the Squares’. By that time, Thomson and Jenkin, both experienced cable engineers as well as able theoreticians, had realised the enormous value of merging their abstract and practical knowledge, science with technology. They saw ways of designing instruments which would vastly improve signalling speeds. Thomson showed, through theory, that by accurately timing a mixture of positive and negative pulses, a sharp, readable message would result. Jenkin verified this, confirming that several words a minute could be sent through cables thousands of miles in length.
But all this came too late for the 1857 cable.
1 Route of the 1858 cable. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
2 Ships of the squadron, 1858. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
3 The paying-out machinery, 1858. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
4 Departure of the cable squadron from Valentia, 1858. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
5 The Niagara and Agamemnon splicing the cable mid-ocean, 1858. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
6 Arrival of the Niagara at St John’s, Newfoundland, 1858. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
7 The Niagara discharging the shore cable in Trinity Bay, 1858. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
8 Hauling the cable ashore in Valentia, 1858. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
9 The cable’s route into Valentia Bay, 1858. (© Cable & Wireless Communications 2012, by kind permission of Porthcurno Telegraph Museum)
3
The Stride of
a Full-Grown Giant
Morse and Whitehouse satisfied themselves, and in doing so satisfied their fellow projectors, that the Atlantic cable was entirely viable. After the Newfoundland debacle of 1855, 1856 proved to be a year of achievement and optimism, even to a point of over-confidence. Maury, for one, could see no difficulty at all, writing to Field in May: ‘It can be done without fail. It can be done by one steamer, and in case of accident while running, the cable may be recovered. When I say a single ship, of course I mean one large enough to carry the cable and coal. The cable need not be large.’ Cyrus Field’s view was that submarine telegraphy, while ‘in its infancy … is in the act of making the stride of a full-grown giant’.
The Atlantic Telegraph Co. was launched by Field in Lon-don in the autumn of 1856. The New York, Newfoundland and London business continued, but in a supporting role only. The idea was that a British company would attract a wider pool of investors, and deal more effectively with governments and cable-makers. The focus of the enterprise thus shifted decisively to London. The new company received an enthusiastic endorsement from The Times, whose leader writer had the utmost faith both in the directors and in the engineers involved:
It is not our custom to come forward as the advocates of joint-stock companies, but surely this project constitutes an exception. The interests of this nation and of the civilised world are so closely bound up with its success that we feel justified in recommending it to the notice of our readers.
It seemed to The Times that the scheme could not fail: ‘The enterprise must be badly carried out indeed if the revenue … is not sufficient to pay a handsome interest upon the outlay.’ As six submarine lines already connected Britain to continental Europe, there seemed no question but that ‘what has been so often and so successfully accomplished can surely be as easily accomplished again, when the only additional obstacle is that of greater length, but under more favourable circumstances’. All would fall before the certainties of the scientific age, the unceasing march of technological progress, and the might of Victorian Britain:
Habit has so familiarised us with the marvellous triumphs of physical science that we have ceased to feel or express astonishment at results, which, not so many years ago, would have been dismissed from the consideration of rational men as the visions of a fantastic imagination.
There was no doubt, no doubt at all, according to The Times, that progress would roll on unceasing. ‘Many persons now living … will live to see the year AD 1900. It will be a changed world then!’
This huge confidence was a double-edged sword. On the one hand, it was a vital element in raising money and political support to lay the cable. On the other, the cable’s enthusiasts were carried away by their own rhetoric. Self-belief closed down the supporters’ critical faculties. At a time when a measured overview of the scheme was called for, the company directors were happy to encourage rising levels of excitement, which made attracting investors so much easier. The scheme, it seemed, could not fail, and would pay large dividends to boot. But of course, the higher the expectations, the greater the disillusion if anything went wrong.
As Morse was completing his London experiments, Field and other directors actively looked for more support. In November, Field was in Liverpool, addressing a crowd of merchants in the underwriters’ rooms. The telegraph, he told the assembly, extended in total 42,000 miles beyond St John’s, across British North America and the United States. All that was needed to connect it to the European network was ‘a single line, 1,900 statute miles in length’, which could be laid in less than a week at a cost of £350,000. A sample of cable was passed around. ‘Now that’s the thing to tell the price of cotton!’ exclaimed an admiring broker. Field hardly needed to spell out to this gathering, many of them engaged in trade with America, the value of almost instantaneous information on commodity prices and other commercial news. At the moment, he reminded them, they could not send a letter to New Orleans and receive a reply in less than forty days. With the cable, because of the four or five-hour time difference, their telegram would be in America before they had sent it.
The Atlantic Telegraph Co. was incorporated in October 1856, with 300 shares of £1,000 each. Field took twenty-five shares, as did John Watkins Brett. The capital was increased by £50,000 a few days later. At its launch, the company had £79,000, with a further £75,000 subscribed from America. Before the shares were ever offered publicly, a total of £180,000 had been committed by the promoters and their friends. The £350,000 had been secured by December 1856. This capital was raised without any need to advertise, despite the high individual cost of shares, with many shareholders ‘gentlemen of the first standing in this country and the United States’. Brett and Field were to be due an enhanced share of profits, for fifty years following, but this would not come into effect until shareholders received an annual dividend of ten per cent. In exchange for the higher returns, the Newfoundland concessions and other rights and patents held by Brett and Field wo
uld be signed over to the company. Further landing rights in Newfoundland and neighbouring territories were also acquired by the new company.
Though it had been easy to raise the money, Field was still keen to attract support from the British and American governments. In October 1856, accompanied by Morse, he gained an interview with the British Foreign Secretary, the Earl of Clarendon. Clarendon was surprised at the scale of the project, and asked what would become of it if the attempt failed. Field is supposed to have replied, ‘Charge it to profit and loss, and go to work to lay another.’ The minister gave a strong hint that the government would do all it could to help, passing Field over to James Wilson, Secretary to the Treasury and a man of great influence. Wilson entertained Field at his home near Bath. Afterwards he wrote to Field confirming the government’s proposals. They would provide ships for new soundings, or to recheck previous soundings, and possibly assist with the job of cable-laying. When the line was working, they would pay £14,000 a year, or four per cent, on the New York & Newfoundland Co.’s capital of £350,000, until profits reached six per cent, and then £10,000 a year for twenty-five years. In exchange, they expected free transmission of official messages, which would take priority over all others. Finally, the British government retained the right to control increases in telegram charges.
The Cable Page 5
