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History of the Atlantic Cable & Undersea Communications
from the first submarine cable of 1850 to the worldwide fiber optic network

Thomas Bolton & Sons

Introduction: Thanks are due to Edward Bolton for his suggestion to write this article. Edward’s great grandfather, Alfred Bolton, ran Thomas Bolton and Sons Ltd. at Oakamoor during the period when they were one of the leading suppliers of copper wire to the cable industry.

Thanks also Peter Wilson for supplying much interesting material on the cable connection, including copies of his great-great grandfather Richard Wilson’s wire books recording the production of copper wire for the Atlantic cables, and photographs of the gauges used to measure the copper wire as it was produced.

Much of the detailed information on the company’s production of copper wire for submarine cables is taken from John Morton’s book Thomas Bolton & Sons Limited: 1783-1983. The Bolton company continues in business today as Bolton Copper Limited, although many of the Victorian factory buildings at its present Froghall headquarters have recently been demolished and the land cleared for redevelopment.

--Bill Burns

The firm of Thomas Bolton & Sons traces its origins to a metal plating workshop founded by the family in Birmingham in the 1780s. By 1838 Thomas Bolton had set up a steam-powered factory for copper and brass fabrication at Broad Street, Birmingham, the “Birmingham Metal Works”. The Post Office Directory of 1845 lists the firm as a “manufacturer of rolled metals, wire, tubing etc”. When Thomas began to suffer from ill health in the late 1840s, his eldest son Alfred Bolton took on much of the responsibility for running the firm right at the beginning of a period of rapid expansion in the copper wire industry.

The 1840s saw the first impact of electricity on industry, one early application being the land-based electric telegraph. As these overhead telegraph lines used iron wire, there was no market initially for copper wire, which did not come into its own until the beginnings of the submarine telegraph in 1850, when the first attempt was made to lay a cross-Channel cable from England to France. Here electrical conductivity was far more important than mechanical strength, and so there was no alternative to copper.

In 1850, the Submarine Telegraph Company was formed with a capital of £2,000, shares of £500 being held by J.W. Brett, Charles Fox, Francis Edwards and Charlton J. Wollaston. Wollaston was appointed electrical engineer to the company and was instructed to order the copper wire. He met with Alfred Bolton at the Broad Street works and gave his specifications: the wire should be of 14 Birmingham Wire Gauge (0.083" diameter), and should be made in continuous lengths, each weighing 30 lb, equivalent to unbroken lengths of about 500 yards.

As an indication of the then primitive state of wire drawing, Alfred Bolton noted at the time that the present standard was for bundles of wire weighing 4 lb, of length about 80 yards, and the works foreman, on hearing Wollaston's specifications is reported to have said ‘Does the man think I am a fool?’', so impossible did he consider such a job to be. So Wollaston was given little choice in the matter, and the wire was delivered to the Gutta Percha Company in 100 yard lengths. These would be covered with gutta percha to ½" diameter, and each section joined by a ‘bell-hangers twist’, the splice being covered with soft solder.

25 nautical miles of cable were made, to run from Dover to Cap Gris-Nez. The cable was successfully laid on 28 August 1850, but quickly failed, due perhaps to a French fisherman having hooked and broken the wire. However, no specification had been made for the conductivity of the copper, as this was not thought critical at the time, and testing of the cable had been rudimentary. 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.

1851 cable

Although this first attempt was not a commercial success it proved the feasibility of such an undertaking, so in the following year a new attempt was made. with greater attention paid to the details of the cable specification and construction. The 1851 cable consisted of a core of four strands of copper wire, each of 16 gauge (0.065" diameter), covered with a double layer of gutta percha, and surrounded by a covering of tarred hemp. This in turn was enclosed in spun yarn, and ten galvanised iron wires were wound in a spiral around this. The armouring wires were supplied by Richard Johnson Brothers of Manchester, later Richard Johnson & Nephew.

It is possible that the copper wire for this cable was made not made by Boltons, as Alfred Bolton’s diary for 1851 makes no mention of it. The wire may have been made instead at Oakamoor, Staffordshire (then the premises of the Cheadle Copper and Brass Company), as there are several references to a Channel cable being made there. Regardless, Alfred Bolton was convinced that electricity was to play a great part in modern life, and began to consider how he could capitalize on this. As the importance of good conductivity was not yet appreciated, Alfred's first concern was the production of longer lengths of copper wire, which he saw would be essential to supply the submarine cable business.

By August 1851, Alfred was at work expanding the wire-making facilities at Broad Street and improving the machinery and the wire drawing-blocks, which resulted in Boltons having one of the most up-to-date wire-drawing shops in Birmingham. And then towards the end of 1851 Thomas Bolton was offered the purchase of the Cheadle and Oakamoor works of the Cheadle Copper and Brass Company. Oakamoor was located about 50 miles to the north of Birmingham, and the factory there had large and spacious wire-drawing workshops with room for expansion.

Thomas and Alfred visited Oakamoor in February 1852, accompanied on one occasion by Francis Edwards and Charles Wollaston, two of the directors of the Submarine Telegraph Company. It is clear from this and from the way that Oakamoor was run once the Boltons had taken over that their main aim in buying the works was the expansion of the manufacture of copper telegraph wire. The Boltons' offer to purchase the Oakamoor premises was accepted, and the agreement was signed on 1 March 1852.

Alfred Bolton was immediately put in charge at Oakamoor, and a month later he was ready to re-start production. The key man for wire-making was Richard Wilson, who had been the victim of religious persecution and in consequence had left Oakamoor and moved to North Wales. The Boltons however persuaded him to return and continue as head of the wire-making department. On 2 August the first five tons of copper telegraph rods were noted in the accounts. On 15 September, Alfred was busy sending off wire, and on 24 September a consignment of wire was sent to the Gutta Percha Company to be covered with insulation. In the first five months of operations at Oakamoor 55 tons of telegraph wire were made and dispatched.

1853 also saw the first foreign order for copper wire, placed by the Danish Government for a cable across the Denmark Strait, and the Dover-Ostend cable required 480 miles of 16 gauge copper wire. This was the standard gauge used in submarine cables up to 1856, established by the success of the 1851 cross-Channel cable, which had used this gauge of wire.

Thomas Bolton died on 5 December 1853, and the business, together with the property belonging to it, was left to his sons Alfred and Francis. Alfred took full charge of Oakamoor, while Francis ran the Birmingham factory at Broad Street. Oakamoor soon came to be the main part of the business, and Alfred and his sons the prime movers, as Boltons began to specialize in the electrical applications of copper; their copper production for the next thirty years being primarily wire for the telegraph industry.

In 1854 another seven submarine cables were laid. One of the two foreign orders was the largest yet received by Boltons: 660 miles of number 16 gauge for the French Government’s line to Corsica. The accounts show that 158 tons of telegraph rods were in stock at one stage.

1855 was a quieter year for cable installations, and Alfred Bolton took the opportunity to upgrade the wire mill with new drawing equipment and to make extensive repairs to the water wheels and the steam engine. A copper-refining furnace was set up, Alfred (perhaps on the advice of William Thomson) having already recognized the importance of improving the purity of the copper used for telegraph wire. The year saw only one order, from the British and Ottoman Governments for cables to assist with the war effort in the Crimea. Some 450 miles of 16 gauge cable with a single conductor were made with no armouring to ensure quick delivery.

The First Atlantic Cable

The slowdown of 1855 and early 1856 gave the company time to prepare for its part in what would be a large project, Cyrus Field's Atlantic cable. Field and his associates planned to lay the cable in the summer of 1857 from Ireland to Newfoundland, a distance of about 2,000 miles.

In 1856 Glass, Elliot and Co made cables to link Prince Edward Island to New Brunswick, a distance of about twelve miles, and Newfoundland to Cape Breton, Nova Scotia, a distance of 85 miles. These cables saw the first use of a multi-strand conductor, having seven 22 gauge copper wires instead of the single solid wire used in prior cables. The stranded conductor had two advantages: it made the cable easier to coil and lay, and it provided some protection against losing communication by the breaking of a single wire. William Thomson and his associates had filed a patent for this type of conductor in 1854, but the patent was never sealed.

The cable selected for the main run was of this same type, using a seven-strand conductor of 22.5 gauge copper wire weighing 93 lb per mile, or 107 lb per nautical mile. 119.5 tons of copper were required, and using the thinner gauge of wire allowed the wire drawers to make greater lengths than was possible with the earlier 16 gauge standard. The armouring consisted of eighteen strands of 22 gauge iron wire, with seven wires to each strand.

Charles Bright and William Thomson knew the importance of using the purest copper for maximum conductivity, as this would affect the signalling speed of the cable, but tests showed that the copper used in the first Atlantic cable had only about 50% the conductivity of pure copper. Unfortunately, the tight deadlines on the project meant that whatever copper was available had to be used.


Because of the large amount required, the manufacture of the cable was split between Glass, Elliot at Greenwich and Newall’s at Birkenhead. On 7 January 1857, Alfred Bolton went to London to make the arrangements with John Statham, works manager of the Gutta Percha Co, for the Atlantic cable wire to be insulated, and at the same time saw the representatives of copper smelters William Foster and Co, about the copper. He had to produce about 20,000 miles of 22-23 gauge wire in five months, a total weight of 108 tons of copper, and in the longest possible lengths. Alteration to the rod blocks and to the large engine were made in January. In the event, the task proved too much. About 60 tons of wire were made by Boltons and the rest was made by their neighbours in Birmingham, J. Wilkes & Co.

The shortage of iron wire proved an even greater problem as over 380,000 miles were needed. By the 12 June the Engineer was commenting that ‘the daily consumption of fine wire (for the Atlantic cable) has been greater than all the wire-drawers in England could furnish.’ The cable was tested for conductivity in lengths of 1 to 1.5 miles. The testing was done under water, but at no fixed temperature. Finally, on 6 August 1857, the cable-laying got under way. The British ship Agamemnon and the United States Niagara sailed from Valentia Bay on the south west coast of Ireland. 334 miles were laid in three days, but the cable broke as the depth increased to over 2,000 fathoms. This put an end to the expedition for the time being.

Further deep-water trials were made at 1,800 fathoms in the Bay of Biscay. 900 extra miles of cable containing about 37 tons of copper were ordered to replace what had been lost. This time William Thomson forced the Atlantic Telegraph Company to insist on ‘high conductivity’ copper in the contract.

In 1858, a second attempt was made to lay the cable, using the same two ships, carrying the rest of the original line and the extra cable which had been ordered. This time the ships were to start in mid-Atlantic and then steam in opposite directions. The attempt was successful, and on 17 August the first message was transmitted across the Atlantic. There was naturally great excitement at the achievement, but after several weeks, a fault developed, and the signals became more and more unintelligible. After 700 messages had been transmitted, the line failed completely.

Despite the loss of the cable, important lessons had begun to be learned, particularly in relation to conductivity. After 1858, the copper smelters were brought to the Gutta Percha Co’s works to see conductivity tests being carried out on their copper. It was seen that some ores produced more impurities than others, and this began the improvement in the copper brought about through the ‘best selected’ method of smelting. From that time a branch of copper making grew up called in the trade ‘conductivity copper’. By 1861, a cable of 81 per cent conductivity as compared to pure copper had been produced and by the time of the second Atlantic Cable in 1865, 96 per cent had been reached in commercial copper wire. Alfred Bolton worked with the smelters to ensure that only the best copper was used in his wire. In February 1858, he himself worked in the Oakamoor refinery for a few days, studying the matter at first hand. Another aspect of manufacture over which he could excercise some control was the electrical testing, and in his next major submarine contract this was given a high priority.

Further improvements were made to the wire mill. Alfred began to install a new horizontal steam engine in November 1858, bringing the number of steam engines on the site to three. In March the following year a full-time engineer, James Bourne, was taken on, to be in charge of them.

Finally, on 29 March in this significant year in the firm’s history Thomas Bolton II was born, Alfred’s third child, and eldest son. He was to follow his father as the leading personality in the company, sharing with him strong interest in scientific matters.

1859 was to be the busiest year yet for the submarine telegraph makers. 310.8 tons of copper wire were made for 2,906 miles of cable. In the first few months of the year, Alfred Bolton was re-equipping the rolling mill at Oakamoor to be ready for the firm's next major cable contract, the Falmouth-Gibraltar telegraph. The very next day, 7 April 1859, he went to London to see the Gutta Percha Company, the copper company Sims and Co from South Wales, and the cable-makers Silver and Co and on 28 May made his arrangements with the Gutta Percha Company for the Gibraltar telegraph wire. This was made in June under controlled conditions, attempting to overcome in advance all the problems met by the Atlantic Cable by careful attention to design, manufacture and testing. The conductor was thicker than the Atlantic standard of seven 22 gauge wires which had become established for longer cables after 1856. It was to weigh 400 lb a mile, over four times as much as the Atlantic cable. Six samples were tested by Dr A. Matthiesen who found them to give 90.7, 89.5, 79, 78.2, 67.4 and 74.4 per cent conductivity. The wire was still being made out ofdifferent sorts ofcopper, but the average ofabout 81 per cent for the whole cable was a considerable improvement. However, this higher conductivity was bought by quadrupling the weight and therefore the cost of the conductor. Unlike other cables, this one was tested at a constant temperature. The essential connection between temperature and conductivity was to be shown scientifically by the same Dr Matthiesen in the following year. In the event the cable was too late for the ‘laying season’ in 1859. Eventually it was used in 1861 for the line between Malta and Alexandria.

In 1860, a Board of Trade enquiry began into the reasons for the failure of the Atlantic Telegraph Company’s cable. The public interest in the question was considerable, and every leading expert of the day gave evidence. The published report contains over 500 pages. The immediate causes were not hard to find: the haste in manufacture, damage done to the cable in storage and handling in the ramshackle sheds and yards which were used by the cable companies at that time, were quickly identified as contributory causes. But the report went further into the basic principles involved in the long-distance submarine telegraph and its manufacture.

Charles Bright argued that low conductivity was the main problem to be solved. The Atlantic cable had only 40 per cent and upwards, and the core had been too small. The solution lay either in thicker cores or higher conductivity in the copper. He also criticised the weak joints in the wire.

Dr A. Matthiesen presented the results of his investigations into the causes of the different electrical conducting powers of commercial copper. William Thomson had already shown the connection between impurities and loss of conductivity in copper wires. Matthiesen’s experiments showed exactly what these impurities were and the extent to which they affected the conductivity of the copper. He found that the most injurious was the oxide formed by the oxygen which copper readily absorbed from the air when it was molten. This could reduce the conducting power by as much as 28 per cent. He recommended that the smelters inject hydrogen into the copper while it was still in a state of fusion to remove the oxides. Matthiesen also found no alloy of copper would conduct better than the pure metal and in all cases he thought that the aim should be the production of the purest possible copper. His experiments on samples of commercial copper gave 72.22 per cent conductivity for bright copper wire, 81.35 per cent for ‘best selected’ copper, 88.86 per cent for the Australian Burra Burra copper, and 92.57 per cent for the recently discovered Lake Superior copper. His report also pointed out the relation between temperature and conductivity and the uselessness of testing wire for conductivity unless the temperature was constant. His experiments also revealed for the first time that hard drawn copper was 2 to 2.5 per cent less conductive than unannealed copper. This was an important point for Alfred Bolton to bear in mind, as it meant that the mechanical treatment of the wire in his works could reduce the electrical quality of the final product unless care was taken in drawing and annealing.

The report also concluded that twisted strand cable was undesirable, as compared with a solid copper conductor of the same gauge. It was thought that the lengthened path of the current would increase the electrical resistance, and that as the sectional area of a strand was less than that of a solid wire, there was also a loss of conductivity.

Matthiesen’s proposal that the smelters should shoot a jet of hydrogen into their molten copper did not bear any fruit in practice. There was no commercially available supply of the gas which would make it practical. So the solution to the problem of conductivity had to be sought elsewhere. However, one lasting effect of his inquiries was the establishment of the ‘Matthiesen standard’ which expressed the conductivity of a sample of copper as a percentage of that of pure copper, rated at 100 per cent under certain specified conditions. This remained the universally used standard until the improvement of refining and smelting techniques began to overtake it. Before the end of the century, Alfred Bolton was making copper which exceeded the 100 per cent standard!

The conclusions of the report gave Alfred food for thought, and he set himself to find a solution to the problems of making an efficient submarine cable conductor. He sought a solution which would combine the mechanical advantages of a stranded wire, with the electrical advantages of a solid conductor. His first solution was a segmented copper wire. This was to consist of four copper wires each forming a segment of a circle, drawn into a copper tube. In 1862 he was busy experimenting with this, with copper supplied by Sims and Co. By 2 December, he had advanced to the point of getting an order from Chatterton, for it to be used on the proposed Persian Gulf line, part of the telegraphic link with India. He went to Birmingham to discuss with his fellow wire-maker Wilkes about sharing a patent, taking samples of the segmented copper bars with him. From there Alfred went to Llanelli, where Sims and Co had their works. For several days he experimented, with the help of Nevill, to find the best way of rolling the segmented copper bars. It became clear that they were too difficult to manufacture, and a new approach had to be tried.

Alfred Bolton's patent conductor as used on the Persian Gulf cable. See this page for further technical details.

The result of the modifications appeared in patent number 22 of 1863, titled “Manufacture of Wire,” which was filed on 2 January of that year by Alfred Bolton. His idea now was to have a solid rod of copper as the central conductor, and surround this with one or more tubes of copper or copper alloy. The wire was to be made by rolling and drawing the tubes and the rod down to the required dimensions. In some cases, one or more of the tubes might be segmented into one or more parts, but in all cases the outer cylinder must be entire. Wires made in this way, he observed ‘are particularly applicable for electric telegraph purposes’. In January and February the annealing furnace in the large wire-mill was rebuilt to handle this new product. On 19 February Alfred was again in London consulting with Chatterton and Latimer Clark about the segmental wire. Clark was the author of the final report which was mentioned above, summarising the conclusions of the enquiry into the Atlantic telegraph cable. By 12 March Oakamoor was making the patent wire for the Persian Gulf line. The company finally selected a conductor weighing 225 lb a nautical mile. The rods were being supplied by Sims and Co, who Alfred saw in London on 24 March. Alfred wanted to make the rods himself at Oakamoor and the next day, he went to look at ‘a train of grooved rolls for rolling copper rods’. In April, Nevill of Sims and Co sent his manager James Drew to Oakamoor to discuss the manufacture of rods for patent wire. Alfred went again to London on 12 June to arrange the final specifications of the ‘patent telegraph wire’, which were passed on 24 June.

In the end the patent wire did not prove successful, commercially. The order was not repeated, and later lines reverted to the stranded wire of the original Atlantic cable. Despite its undoubted electrical merits—the cable averaged 89.14 per cent by the Matthiesen standard—it probably proved too expensive to make. It did however push Alfred Bolton further along the road to rod-rolling of copper wire with grooved rolls.

The Second Atlantic Cable

Almost immediately after finishing the Persian wire in September 1863, Alfred was taking an order in London for 150 tons of wire for a new Atlantic cable. Plenty of time was to be allowed for the manufacture and testing, to prevent a repetition of the previous failure. An 85 per cent conductivity standard was specified, and the wire was required in 38 lb lengths, that is about a quarter of a mile of the 18 gauge wire ordered. This was to be stranded into a conductor with seven wires weighing 300 lb a mile.

The testing apparatus previously used at Oakamoor was examined by another of Nevill’s men from Sims and Co and a new apparatus was sent from the Gutta Percha Company in October. But all was not going smoothly. On 24 November, Alfred was in London seeing the Gutta Percha Company about the Atlantic Telegraph contract which they wanted to alter or annul. He does not say what the problem was, but it may have been to do with the length of wire which was expected. 38 lb lengths of 18 gauge copper was considerably more than the 6 or 7 lb normally made. Boltons were obliged to make changes in their machinery to cope with this, and the cost of this may have been a source of contention. However, the ‘Atlantic matter’, as Alfred referred to it in his diary, was finally settled at a meeting with Chatterton in Birmingham on 10 February, 1864.

The total order of some 300 tons of copper wire was again shared with J. Wilkes, with Boltons contracting to make 200 tons of it. The first batch of Atlantic wire was drawn on 3 June 1864, and quantities were drawn regularly every fortnight until 20 June 1865 when the order was finished. In fact 173.25 tons were actually made and delivered to the Gutta Percha Company. In the Oakamoor wire production book, the Atlantic wire gauge is referred to as ‘49c’, instead of 18, the Birmingham wire gauge figure. This is an illustration of the confusion of gauges which existed at the time, which was not cleared up until the legally enforcable Imperial Gauge was set up in 1884.

Brunel’s Great Eastern had been hired to lay the cable. She set out from Valentia Bay on 23 July, with a guarantee of £20,000 a year from the Government plus 8 per cent on capital if the project was a success. Over half the cable had been laid when it parted on 11 August, and all the grappling rope was used up in the attempt to recover the lost end. As with the first attempt the cable had to be abandoned, leaving 1,186 miles of the line on the sea bed.

Almost immediately, new cable was ordered. Alfred Bolton broke his holiday in Llandudno to meet Chatterton in Birmingham and take an order for 125 tons of wire. Production began at Oakamoor on 21 September 1865. The wire drawing was finished on 17 May 1866, Boltons having made 113.4 tons of copper conductor.

Instead of simply finishing the existing cable the following year, it was decided to take the opportunity to lay a second cable at the same time. By amalgamating companies, a total capital of £600,000 was raised. Alfred Bolton himself was approached at Oakamoor by Chatterton to take £8,000 worth of shares in the new Anglo-American Telegraph Company. On 30 June, the Great Eastern sailed again, this time with one complete new cable, largely unchanged in design from the 1865 one, except for the use of galvanised wire for the armouring, and a length of another sufficient to complete the 1865 cable. On 27 July, Alfred Bolton noted in his diary:

1866 Atlantic cable—completed laying 8.45 pm. They have not yet tried to recover the 1865 cable.

This was not done until 2 September, and the old and new ends were spliced at 5.50am, a fact also noted in Alfred’s diary. Within a few days both cables were working. A dramatic demonstration of the power of the telegraph to conquer time and space was made by Latimer Clark. He had the ends of the two cables joined at Newfoundland and then sent a strong signal across the Atlantic and back in little more than a second.

The success of the cables was greeted with great public enthusiasm. Many banquets were given in celebration of those who had made the Atlantic telegraph possible. Alfred himself decided to commemorate the occasion personally by ordering a grand piano.

Many more deep-sea cables were laid after the successful outcome of the transatlantic telegraph. The next major concern for Britain was a direct link with India. Parts of this had been attempted before 1866, but with no overall success. Now there was a rush of cable laying to the East up till 1880. Oakamoor was immediately involved, turning out 10 tons of wire for the Abyssinian telegraph in October 1867.

The British were not the only submarine cable layers now. In 1868 the French Government ordered its own transatlantic cable. They turned to Boltons for their copper wire, and Alfred went to Llanelli in August to talk to Nevill about the copper for it. The first wire was drawn on 4 September, and the total order of 216 tons of ‘56c’ wire was finished in April 1869.

The 1870s were busy ones for Thomas Bolton and Sons as the orders for submarine cable wire multiplied. There are no details of these orders, unfortunately. Larger and more powerful plant was installed. In 1870, six new wire blocks were completed. New breaking-down rolls, wire-strip rolls, and large rod rolls were put in. More grooved rolls were being considered in 1873. By 1881, there were new large rolls for rolling wire- bars into coil, and new grooved rolls for rolling rods from the coil ran for the first time in February. By this time the wire-making process in general at Oakamoor looked like this:

wire bars —> [rolling]  —>  coil —> [slitting] —> square rods —> [rod rolling] —> round rod —> [drawing] —> finished wire

After 1880 the tempo of submarine cable laying dropped, and it became necessary for Boltons to look at the land telegraph for a market for copper wire.

Last revised: 23 June, 2022

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